The finned dart sabot rounds have been some of the most difficult things for me to get to work and I'm dealing with half the scale you are. You can't put a wad behind the fins because that will just crush the fins. The sabots double as the gas seal. Most of the darts we have tested (CanaDart, Anferov bullet, Dynaslug, and Sauvestre) have lugs on the shaft that match up with lugs on the sabots. Almost all the pressure acts on the sabots and pulls the dart down the barrel as the dart is locked onto the sabots. A common failure was when we tried to push the rounds too hard - it stripped the lugs right off and the sabots went flying at a high speed and the dart followed along at a very low velocity. The video we just did with the CanaDarts used very brittle 3d printed parts. I had to use a small 25 grain charge of Pyrodex and a spoonful of coffee as an inert buffer to fill the space. They worked OK but we were only getting about 500 to 600 fps.
Oh snap! Wow! Thanks for tuning in! I just recently found your channel and subscribed and your sabot dart made me realize that the rods were supposed to be threaded(and why 🤣😂) like two days before this video came out. I’ve so appreciated the knowledge that you share on how to cushion rounds and the ways you load them and the gas seal ideas. I hope you truly know how much I appreciate your channel and I didn’t expect this to even make it anywhere near a comment from you! I will for sure take your tips into account and get a working V2 version in the future. I greatly appreciate the tips and you tuning in in the first place! Keep making those amazing videos.
@@TheCannoneer One of my viewers left a comment saying you were having trouble with your sabot darts so I had to check it out. The viewer-created projectiles have been fun to do and I've been surprised at the creative ideas people have sent. People have been telling me that we need to scale things up to something like you are doing so it is great that you are taking that opportunity. The 12ga. stuff keeps me busy.
@@taofledermaus I was checking out the back catalog and there's some seriously weird things folks come up with. I have a hard enough time making a big round lead ball half the time!
Your problem is simple, the sabot is supposed to lock on to the penetrator and is used to accelerate the penetrator down the barrel with the sabot releasing and flying free once the penetrator exits the barrel. Your base was is crushing the stabilizing fins upon ignition.
Your biggest problem right now is your APFSDS projectile is getting left behind by the sabots because there's nothing really holding them together. Real APFSDS rounds are held mechanically to the sabot by a series of machined grooves in the sabot and projectile locking them together. The sabot has the majority of the surface area and is where the majority of the "push" from the gunpowder goes and it pulls the APFSDS projectile down the barrel along with it. What might work best in your case is to make the metal rod go down to the base of the fins and have an additional base to push the projectile from behind. That way the majority of the force is the new base pushing on the rod from behind instead of trying to pull the rod from the front. You would have to redesign your sabot a little to make sure it could also hold up to getting pushed from behind, but that should be mostly making the rear section thicker. You could also try printing your fins thicker and from Carbon Fiber TPU, which is significantly tougher against sudden shock and impacts while still being pretty stiff. It's pretty abrasive on brass nozzles so you would need to get at least a hardened steel nozzle.
I don’t know if I can print carbon fiber on my printers! I’ll have to look for sure! I was wondering what the all thread was about inside them but that makes complete sense. Keeps everything together.
@@TheCannoneer All you really need is a hardened steel nozzle for your printer(Short term) and hardened steel/replacement extruder gears(Long term) if yours are brass. If yours is a threaded removable nozzle it's almost certainly a standard size nozzle that's widely available anywhere that sells 3d printers and accessories. If its something more proprietary, like from Bambulabs, they usually sell hardened nozzles or may come standard on their high end models.
@@tu-jx6wh there are also tungsten carbide nozzles as well, they don't wear at all, they will basically last a lifetime unless you're extruding filament loaded with diamond powder, which I don't think exists...
The easiest answer for the rod is to make it from a threaded steel rod and have the three print sapo interact with that you could also easily machine a metal tip that you could then screw on to that rod
@@TheCannoneer Using a section of all-thread as your projectile might be a quick and dirty way for your sabot to retain the penetrator rod as it goes down the bore. Keep the sabot pulling by threading its inner section to match the rod.
1. Don't make pressure push on the fins with the pad 2. add grooves on the rod so the sabots have tight grip 3. Add aerodynamic surfaces on the front of sabots that will better push them apart after leaving barrel - I really like your creativity 🙂
Much appreciated! I didn’t know these rounds were pushed by the sabot and not the fins when I made these but yall have wonderfully explained that so I was unknowingly putting pressure on the wrong parts. We will be a redesign and get these working! Thanks for the tips!
Here is an image of what Martin is talking about. I believe these sabots are normally split lengthwise into three pieces. pbs.twimg.com/media/DmcwFhqVsAAGF3C.jpg
The sabot needs to pull the dart from the front. Not be pushed from the back. In all APDFS rounds from 7.62x51 DU to 120mm. The sabot pulls from the front. It's also cupped at the front to catch the air and separate from the dart as quickly as possible after it leaves the barrel. I'm sure people have mentioned the grooves normally found on darts so the sabot doesn't slip. An interesting fact. Surplus 7.62x51mm DU has made it onto the civilian market. It's really rare but cool.
4. Keeping it subsonic also helps. Typical black powder shot is transonic -the worst possible speed for this purpose. I've tested this kind of things with air rifles. Just a half gram piece of florists wire with rice paper vanes and a wood plug seal. From a low power target rifle , ca. mach .4 speed, they work fine, consistently stick point first on 4" board at 10 paces. From full power mach 1.2 vermin rifle they come out sideways.
Taufladermaus did a video like last week shooting some flechette rounds. It seemed like the sabot fully encased the flechette and had a cup shape at the tip above the tip of the projectile so once it's out of the barrel it catches air and splits instantly. I feel like that would work well here.
I shall have to check his channel out some more. I didn’t even know he existed until recently when y’all started suggesting it and he’s got some many cool designs! Thanks for the tip!
@@TheCannoneer I was going to suggest that channel but figured you knew. The 12ga designs would translate well to your barrel I bet. The other comment re a concave cup leading the sabot parts sounds right on. Clean separation
1) I'd try a different 3d printed material- I've used PETG sabot rounds in my muzzleloader, they don't seem to break up at all (less brittle) 2) I'd try a softer wad- maybe felt layered or t-shirts layered 3) That penetrator needs to be nose-heavy and tail-light. The first 1/4-1/3 of the penetrator should be lead or steel, the body should be composite, and the fins 3D printed Love this channel dude, keep up the great work! I hope these suggestions make it to you!
Several people have made one suggestion of cupping the front flange as an air catch when it leaves the barrel the air will catch the fina pulling them away from the penetrator. But the biggest thing for stability is not using a pusher behind the penetrator. The sabot needs to pull the core out of the barrel. This is because without a perfectly balanced core any slight instability is amplified by the pusher. One of the easiest ways to get the sabot to lock in to the core is cut a small groove around the shaft of the penetrator. The with the sabot add a small lip on the inner diameter to fit into the groove.
On APFSDS, dart shaft's positive ribbed while Sabots' interior's negative ribbed so the sabot grips the dart shaft and doesn't blow out. Current construction is a soft "rubber gas check" then delicate plastic fins, then metal dart. On firing, the rubber and plastic fins probably give some or shatter. Maybe rag packing over powder then a short wood cylinder behind the dart as a rigid pressure bearing point. The solid shaft should carry all the way back to the bearing point - wood dowel -( the fins should end at the back of the dart). The sabots look sound, they only need center the dart, elastics alone should do. ..just a idea... besides, wood is cheap ! ..cheaper...
@TheCannoneer Definitely check out how shotguns use a wad with a bit of spring-like material instead of a solid puck to push the round. It should help with the fins breaking on firing! Loved the video btw
Don't put wadding of any kind behind the fins, that's only going to load them and destroy them. Serrate the penetrator and have the sabot grip the serrations to pull it through. If spacing and a smaller charge doesn't help then you'll have to go with an all metal dart. Normally the fins are in the propellant explosion, they are NEVER pushed.
Someone pointed out the TPU base is probably was just piercing a hole through and blowing everything apart in the barrel which makes total sense. I’ll have to revisit the metal fins idea and a few harder base plate materials….
Thank you guys so much for all your wonderful ideas on how to improve this round! We will get this working in the future with all of your improvements. Thanks for your support!
For a muzzle loaded apfsds you need a flat bottom piece that goes behind the flechete and support the sabot extrude a rod enveloping the flechete 30% of it is the base or the piston this is a single piece the remaining 70% is the sabot and you cut it in 2,3or 4 parts from the top and the head need a cup or c shape to catch the air to peal apart And attach a pvc tube to the reloading rod so it doesn’t touch the flechete only the sabot Edit and use paper strips to hold it instead of ruber or tape
And I don’t know if it’s will be useful but I shot a “apds” on my air rifle using a mold to envelop half of a nail in compressed wet toilet paper it works well both as a single solid piece or as a solid base and 2 peals apart mid ,it’s shrink a little wen dried but you can umidify (don’t wet it again)before shooting
Two options for making the penetrator better. Either make the overall length of the penetrator shorter or the fins longer. That would help it as far as staying on the flight path
I see good comments here. Mainly I would just make the discarding part of it a chunky cylinder that fills the bore and encapsulates the fins in addition to the penetrator to support everything as well as possible. 3D printing lends itself to chunky designs and your fins are too flimsy to be carrying all that acceleration by themselves. You might even see about adding a steel cross pin into the penetrator a little further up that can also key into the discarding sabot to take some of the stress off the fins. This would allow the sabot to pull directly on the penetrator taking some of the force away from the back. I imagine that even if the fins are surviving, the penetrator is getting driven back through the fins and through your TPU pushers like the penetrator that it is lol
There's another guy on youtube called flasutie id hit him up and ask him for ideas since it's one of his specialties and he might be able to help i hope you get it to work and i can't wait for the next video.
taofledermaus is another good resource if you haven’t discovered him yet. He basically does the same thing just with 12 ga shotgun loads. There are several videos of “apfsds” rounds going through iterations to find what works. I imagine it would be a good resource since I think people have gotten them to work, though on a smaller scale with about the same acceleration. Idk how that scales to a small cannon though.
@@rofllcats I just recently found his channel since yall mentioned it! His loading techniques with the cork seems super handy and I will be sure watching more of his videos for some tips!
If you look at the tank's APFSDS, it's the back "bulge/ring" of the sabot that seals the case and is pushed by expanding gases (the front one keeps penetrator straight). The fins are actually inside the propellant when loaded. I think in your case those TPU disks simply push through stripping fins, because the penetrator is not supported well enough. Maybe redesigning the sabot in a way that it is pushed directly (so the sealing bulge/ring is behind the fins), and adding on the inside something that would grip the penetrator along its length would help. Anyway - great video.
That makes total sense and when I found one of those discs it did have a hole in it. I bet you’re totally right as to what’s happening inside there. I didn’t realize how those rounds really worked until y’all explained it and that makes total sense. We’re pushing from the wrong part and the stress is on the wrong piece. Much appreciated for the tips!
@@TheCannoneer yeah apfsds is really cool in its simple science. my countoured fin base cap idea was more of a solution geared towards your current design layout. but if you actually redesign entirely and aim for the proper shell mechanics i think youll see much more success and much easier than trying to improve your current one.
For old school artillery, you need old school ammunition. Forget the 3D printed fins, just make a nice penetrator spike and fit it with a suitable discarding sabot. Bore a hole through the end of the spike and tie some hemp line with a monkey fist ball knot made a few thousandths shy of diameter of the barrel. Leave about 4 - 6 inches of line between the spike and the knot. Soak the line in water over night, this will keep it from combusting when fired. Ensure the monkey fist knot is still about the same size as the sabot outside diameter, dry it out a little if its swelled with water, coil the line to butt the knot up to the sabot then load the lot with a wad to keep the monkey fist off the powder. The ball should trail on the line when fired, inducing drag and stabilizing your penetrator. With some fine tuning on the size and weight of the rope ball, you should be successful.
I would also recommend finding the center of gravity of the dart too. You can do this by measuring the length of the dart and then suspending the dart by a single string at the measured center of the dart. Make sure you start with more length at first so you can cut it into the right length as needed. Do this properly and you’ll eliminate all tumbling after the dart leaves the muzzle.
OH YEAH jsyk, real APFSDS rounds have ledges / steps on the penetrator that interface with some on the sabot, so the sabot actually drives the central projectile. here, the sabot may just slide off the penetrator during firing as there is no mechanical interface
As much as we love 3D printed projectiles, they have limits as far as surviving violent acceleration as you would see in a black powder cannon. It's not impossible, but requires additional design improvements to prevent the projectile from being obliterated to avoid the plastic from being destroyed during firing.
Oh snap! Thanks for tuning in! You guys have great videos too! I’m hoping to get a working version with some of the tips everyone here has been suggesting. I truly appreciate you guys checking us out! If you guys are up from some exploding cannonballs…. Hahaha.
You might try TIG welding some steel fins onto your penetrators. You might need a jig to hold the fins in place wile you weld though, to keep the heat from warping them out of alignment.
The sabot of the round itself is suppossed to be exposed to the pressure gasses, not a baseplate behind the round. the fins were clearly not strong enough to hold all the force. The problem with your round is that the sabot will get launched out without the dart if you had no baseplate. To fix that you need grooves on the dart and the sabot so they get locked together while still in the barrel.
That makes complete sense when you look at the cross section. I’ve got to make it work the other way around… as it’s being pushed from behind on the fins now. I didn’t put that together until now. Thanks!
He actually commented on our channel last night too! Dudes been a wonderful wealth of knowledge on his channel to load things. I just started watching his channel a bit ago but it’s so informative.
@@TheCannoneer yeah im personally subscribed, love his content myself speaking of subscribing, the idea of shooting things out of cannons definitely piqued my interest, ive subscribed to you too :)
I dont think the 3D printed fins are going to hold up to the forces involved. An alternative design would be a yo-yo style to generate the spin. Sounding rockets use a yoyo to despin, but a modified design could also spin up the projectile. There are two ways. The first design is simpler, you attach a wire to the Sabot petals and spool the wire around the projectile. As the petals are flung outwards, they unwrap from the projectile, spinning it up. The second way would be harder but more similar to rocket designs, you would need to have some small weights on the end of wires with a slight rotation already present, if the wires are winched inwards to bring the weights closer to the projectile, the moment of inertia will decrease and the projectile will exponentially increase in rotational speed to keep the angular momentum constant. Having the wires pass through holes in the projectile and anchored back to the cannon or the sabot could winch the wires inwards if done right, the other ends of the wires just having some weights attached to them. The best way to think of this second idea is a figure skater pulling their arms in to spin very fast, the same principle will apply to the sabot if you can pull mass inwards to the center of rotation somehow.
You could also just try to make something more aerodynamically stable. The idea of the fins, besides spin stabilization, is to put the center of drag behind the center of mass. Alternatively, if you were to cast lead onto the nose of the projectile, it would be nose heavy and much more stable. Lead is over 50% more dense than steel, and very easy to cast. Real APFSDS rounds use tungsten or depleted uranium for the penetrator because of the increased density.
Theres alot of good information in the comments to recap the main changes that you need to make if you want this to work 1. you cannot pit wadding behind the fins bc the fins cannot be made strong enough to be load bearing and will be crushed by the wadding 2. In a normal sabot round the petals interlock with grooves on the projectile and the petals are responsible for pulling the projectile down the barrel and obturating the barrel (thus taking the load of the fragile fine) Also a note on terminology, what you refer to as the "petals" the parts the hold the projectile are called the "sabot", and the part you refer to as the "sabot" is the projectile
@@TheCannoneer i dont know if you have ever seen paul harrell and his "meat target" but id love to see you shoot a "human like" object with grapeshot so we could get an understanding of how deadly these loads were
Im 51 and the kid in me comes out watching someone firing different projectiles at targets . Whether they fire well or break up the explosion and smoke are enough for a smile 😃 😊 im a simple person 😅
First video of yours I saw I was like: " wow, here's another dude with some weird-ass hobby on youtube". Now every video of yours I am like: "WOW HERE IS THE DUDE WITH THE CANNON!". Subscribed.
I did 10 years in the army, and worked with munitions multiple times. What you need is a base that is the bore diameter, with a 3-4 part cast that fits around the projectile that us the bore diameter on the outside, and patches the projectile profile on the inside.
That baseplate disc is transferring the entire pressure load of the black powder charge to the fin assembly, and the damage is multiplied by the difference in weight between the fins and the metal penetrator. What I would do to redesign this is modify the baseplate and fin assy to where the baseplate disc can support the pressure load and transfer it directly to the penetrator rod, which seems to be the most difficult object to get up to speed quickly. The disc can be done away with entirely, however, if you cut a ribbed pattern into the penetrator rod and a matching one into the inside of the sabot so it can "grip" the sub-caliber round itself and so that the pressure load is dispersed into the sabot, which drags the penetrator and fins along with as it travels out of the barrel. You might also want to toy with the size of the powder charge. Too much powder means too high of a pressure spike, which means the sabot or baseplate disc would be more likely to shatter under the strain of such a sudden acceleration. I hope this advice is good enough to make a difference, preferably for the better.
Cylinder of balsa split lengthwise. Short small fins that taper flush after 25 % or so of the length of the penetrator. A couple of right triangle gripping grooves forward of the fins. And a minimal amount of Elmer's glue to hold everything together for a couple of yards past the muzzle. A potato cannon bestowed this knowledge upon me many moons ago and it yielded great results after some fine tuning!
Idea: Simply move the fins forward on the penetrator so that the very rear of the penetrator itself is what has the pressure from the pad instead of the fins. This will be the simplest way to resolve the issue with minimal modifications.
I have some experience with similar projectiles from air powered guns. I suggest....1. put in a seal plate that will do 100% of the pushing of the projectile so little or no gas goes past. Allow your steel shaft to set on this plate to better transfer force. The pusher might need a steel washer face as the plastic will just shatter from the force. 2. put tiny pins and sockets in your petals mating surfaces so they can index against each other and remove any rubber bands when you load the assembly. 3. put a twist on the fins to spin stabilize. You might need to make your glue area longer because this will add a torque load to your glue joint. You might also reduces your power charge and slow everything down a bit until you get the thing working as desired.
Beautiful. I just screen shot your comment and that’s gonna be what I’m headed for for one version! I’m going to try a few different designs people have suggested but yours is wonderfully explained and make total sense if I were to make a redesign myself. Thanks so much!
I agree you need a steel base to help transfer the pressure to the rod, I Bellerive right now the sabot is being blown off before leaving barrel because of pressure
There are a lot of ways to make this work on your cannon, depending on what kind of materials and techniques you have at your disposal. for starters, as a lot of other people have pointed out, the TPU plug in this configuration is never going to work, not only because youre pushing the fins, which are certainly going to shatter no matter what plastic you use (even aluminium might be destroyed), but also because the TPU is undoubtedly going to be perforated by the rod unless you make it unreasonably thick. An easy fix to this would be to make the rod go all the way to the rear of the projectile and using a metal plate in front of the plug, then the design of the sabot would have to change to also touch that plate such that the fins dont get shoved into them upon firing. another observation would be to remove everything holding the sabot together, perhaps some white glue can be used to simply hold everything in place, with the idea that it will immediately break apart by the shock of firing, since you definitely dont want the sabot to remain attached to the projectile. A slightly more complicated solution can be found by trying to more closely mimic the way a real apfsds round works. by grinding/machining grooves along the penetrator and designing matching grooves on the printed sabot (ive seen threaded rods suggested, altho its an easy source of something with grooves out of the box, im not entirely sure if the features are large enough for the plastic to hold onto). depending on how weak the plastic turns out to be, those features might just strip off so youd have to use some kind of metallic insert on the sabot (im honestly not sure how youd go about doing that, maybe some steel sheets could be cut in the same cross section as the sabot and then glued on both sides of each petal (petal being the name of each segment of the sabot), and the printed part would obv have to be altered to make sure everything still fits in the barrel snugly and without gaps, perhaps the steel plate could be smaller than and inset into the print to avoid steel on steel contact in the barrel and make sure there are no air leaks (it would be rather difficult to make the flat sheet seal properly)). The final overkill solution would be to make everything out of metal, with the steel penetrator and cast aluminium fins and sabot. with the previous solution there would be nothing protecting the plastic fins from the heat of the explosion so that might fail even if it doesnt get contacted by anything solid, either by melting or shattering, so if a better suited plastic isnt available metal might be the only way. to that end, id recommend lost wax casting, as that allows for the most detailed parts and shouldnt be terribly complicated, altho simple sand casting can certainly work with a lot of post processing. the fins can either be directly cast onto the steel rod (not 100% sure if it would work) or attached later, either screwed or press fit/glued on (obv only go with screwing if pressing fails). youre likely to need help with either process so id maybe try to find a local place that does casting.i certainly hope i doesnt come to this because working with metal casting is quite time consuming and dangerous. Some final considerations as far as the general design goes: >as i said at the beginning avoid holding the sabot petals with anything that could resist the firing process, like tape and rubber bands. altho they might tear apart its also possible they dont at all, too late or in an inconsistent manner, which could mean it messes with the flight path of the dart; >the design of the petals can be changed significantly. this version that tries to mimic the appearance of the real one would probably only work in metal, with the plastic versions having to be significantly thicker to provide enough structural stability and strength. the real darts are designed in the way you see for several reasons: they need to be light (you dont want to waste the energy accelerating something that isnt the projectile), the contact patch in the barrel has to be minimal to reduce friction (the only contact is the seal at the back, which prevents the gases from escaping, and the piece at the front, which serves double duty as something to stabilize the projectile inside the barrel and to scoop the air after it leaves the barrel to ensure the petals release consistently and cleanly), it needs to leave space for the propellant charge (look up images of a complete tank round and youll see how the projectile sits very far into the casing), it needs to separate early and easily from the rod (this is accomplished by the aforementioned scoop). all of this means that if you dont need the utmost efficiency, several of those design considerations can be ignored and you end up with basically a segmented cylinder with a hole for the rod the pass through (and ofc the internal features to hold the rod plus whatever modification would be needed to accomplish this). some extra features that might help would be a taper in the rear (similar to the real one, altho less extreme), which would help squeeze the sabot into the rod by the pressure of the explosion (force vectors and all that), and the scoop at the front to help with the sabot release. Finally, im just an idiot with a keyboard on the internet, so, altho i wrote as if everything was factual, do take this wall of text with a grain of salt (this was by no means an exhaustive list of everything that could be done nor guaranteed to be correct).
It seems like the main issue is the power of the Canon is pushing the fins of the Sabo through the shaft basically destroying the fins before it's even leaving the barrel to fix this it would be better for the shaft of the Sabo to go all the way through the fins
As a physicist, I'd make the parts that are supposed to come off into a cylinder just under the bore size. The cylinder would be long enough to keep the projectile perfectly aligned in the bore. I would put a thin, shallow spiral flute around the outside of the cylinder to impart spin (keeping the projectile accurate). I think i would try an inverted cone on the front of the cylinder that would theoretically be forced shut by the overwhelming presure of the blast (behind) until it leaves the barrel. I'd probably make it out of tpu. Summary: 1. Cylinder to push the projectile. 2. 2 halve 3. Inverted cone in the front to force the halves apart upon leaving the barrel 4. Rifling on the outside of the cylinder to impart spin (forget the fins; if you get this thing spinning right, you won't need em) 5. BIG ONE - Make sure the center of the cylinder is on the center of mas of the entire projectile! You know you've done this correctly when you can balance the entire projectile at the midpoint of the cylinder! This is crucial because it means it will have no force bias inside the barrel.
Penetrators don't spin because the rotational energy fights the forward momentum when it strikes a target, reducing the overall penetration depth. At least that's what I've come to understand over the years. And absolutely a sabot that fully supports the penetrator and centers it. It also has to grip the penetrator firmly enough to ensure full energy transfer, while falling away cleanly upon exiting the muzzle.
@@willabernethy4832 Fins stabilized anything shouldn't spin more than a few rotations a second to cut effects from tolerances on the fin unit. They're forward CG in relation to CP by design, and spinning a forward CG projectile can (usually does at some point) result in a coupling between aero stabilization forces and gyroscopic forces that end up positively reinforcing each other. You end up with a projectile that's spinning around sideways like a cheerleader's baton. Gyroscopic stabilization needs a rearward CG, which doesn't work with fins (wants to correct itself backwards).
@mfree80286 The jobs on the battlefield don't spin. Sabot rounds made to fire from old rifled barrels have ball bearings to engage the rifling and negate the spin. Today's smooth bore cannons on almost all modern tanks were developed specifically to fire sabot rounds more effectively. Admittedly, long, thin, precise fins only a couple of millimeters in height are difficult to produce. Maybe long, thin grooves along the axis would suffice. Something like a 15.1 length to diameter ratio is very important also when it comes to stability and accuracy Either way, it's a lot of fun to figure out how to make physics work for you!
I'll go with what the others have mentioned, the finas will never support being the part receiving the force, the penetrator needs a way to lock it to the sabot while in the bore, abd the fins need to be a tougher material.
The sabot must be metal. Let me explain. If you look at the m1 abrams, the whole entire system doesn’t have any buffers between the shell and the casing. The sabot must also be metal if the projectile is metal, that way the cannon pressure wont make the projectile sheer off any metal holding the projectile in place. I recommend CNC aluminum, it should be strong enough, plus you can print it into whatever you want. Edit: if not already, it should be properly held together on the inside. That way the projectile cant move forward or backward in the sabot, so then the sabot can cleanly release after the cannon fires and it has left the barrel.
Just a thought. If the casing were to not only cover the middle but wrap along the bottom of the fins for more grip that could encourage more of a solid shot. Once the back is out of the cannon there would be the air that could separate the shells and also potentially saving the fins. My biggest suggestion is to have metal fins. You either need to weld medal fins to the bottom of your rods. You can cast them in sand. But you really need to try to keep a total of 4 pieces. The 3 pieces for the shell, and the single stabilized rod.
For starters your dart really should be better connected to the sabot. Remember your dart is absorbing next to no momentum itself, it has so little surface area exposed to the charge, it’s the sabot that’s built to soak up that pressure and spit down the barrel. The dart really only moves because of what’s imparted onto it by the sabot. This is why most tank rounds of the sort will have lugs on the inside of the sabot and outside of the dart, so the former pulls the latter with it. Couldn’t see well if there’s anything of the sort with your ammo.
Food for thought... The APFSDS has grooves which lock it into the sabot. Maybe if you turned a few grooves into the rod, or use a peice of allthread, it may adhere better to the sabot. Also, you need a pushing charge, not a forcing charge. Perhaps loading your cannon to the training load specs might change the pressure dynamic. 😉 And yes, pin the fins. They want for a mechanical connection to the rod.
I’ve realized that I’m trying to reengineer the design to be pushed from the base and not from the sides and y’all have wonderfully explained that to me which I much appreciate. I’ll pin the fins! If I’d have quite known how they are supposed to work I’d probably have done some rethinking!
Move the centre of mass towards front of the round. You can do it by providing draft angle to penetrating dart. Also increase the cup depth of seperator with through holes at each.
This is exactly the kind of science I expected! Edit: Definitely suggest welded metal fins on the next test shots, in addition to the measures mentioned in other comments re: using the sabot as the pusher.
I’m gonna have to get those fins worked up for sure! Got a few different styles suggested so we shall hopefully get one working! So I totally didn’t know the petals pulled the rod and not the rod pushing the petals when I made these!
Remember that on acceleration, every part of the projectile weighs several thousand times what it does at rest. You cannot drive these from the PLA components. What you'll have to do is multifold and this is just an example of ways to make it happen. 1 - The rod will need to extend all the way back to the buffer disk, and you'll need to ensure the disk can't fold around it. A large washer may do. 2 - You cannot rest the sabot on the fins, it will crush them immediately. Drill the rod for a pin to use as a rest, or grind a groove that the sabot can interface with using half a washer embedded in the sleeve to spread the load. You could also add a pin and a small washer that stays on the rod to serve as a backer if you want to keep the current geometry. 3 - The sabots are not acting as a gas check or driving band in this setup, they do not need to be solid. Lighten them as much as possible by skeletonizing them. This also aids in aerodynamic separation. The only reason modern projectiles have this shape is the penetrator extends back into the powder charge and the sabot *is* the driving band.
Oh. and.... the *easiest* way around all this is to make a cone tip that's wider than the rod, and undercut to serve as a notch. Then you can make a full encapsulation sabot from lighter materials, and the projectile will "hang" from the tip under firing forces, and then aid in pushing the sabots away as it leaves the barrel and drag takes over. As the part of the sabot ahead of the tip slides back it disengages the notch AND gets pushed sideways by the shape of the tip. You may need to add a couple angled pins or something to the sabot leaves to engage the notch and spread the forces around so it doesn't rip free, depending on what material you use.
Try using a stabilizing cone instead of fins. Tank training ammunition is cone-stabilized rather than fin-stabilized. Without machining the penetrator to lock onto the sabot petals, that might be the most durability you can get out of this design. Also, ensure that your rear TPU disk ("wad"?) is applying pressure directly to the metal rod, and not the cone or fin stack. Mounting the cone or fins a bit forward of the base of the penetrator will help ensure that the bulk of the force is absorbed by the metal rod and not the printed part, which should leave aerodynamic forces after the round leaves the blast envelope as the only thing the printed part needs to withstand.
Hi, Just an idea that I have seen: Use a length of all-thread rod as the penetrator. You can then use a thread to locate the sabots and lock them to the rod. The gas seal is then on the sabot.
You need to create break groves and only have the thinnest pieces of material holding them together. The tape & bands are flexible and do not break apart. You need to guide the break apart and weaken the material along those break up sections so the force of the wind is stronger and more than enough to break the material. You’d better off using a more brittle material like dried cardboard or very brittle plaster. You’re not using even close the power of a shot real sabots experience when fired so you need to compensate by using material that’s more brittle to get the proper break away affect you’re after
OMG you actually did it, amazing! sad that they didn't work. maybe having metal fins welded to the penatrator would work? Also nice voice over and always great camera work. If you get the APFSDS rounds to work ill send you a nice bottle of Dutch liqueur!
I try to make sure I keep my promises! I’ve still got the flechettes lined up but I can’t shoot them at our normal ranges. Only one will let us and it’s an hour from my house so I don’t get there often but they will be one of these days. I’ll raise you a glass on the working video one of these days hopefully!
The sabot is supposed to be the thing that absorb the energy. Make groves and sabot with groves to propel the dart. Also, use a 2 piece sabot with a air drag that would split it apart when it is on the air.
There's a reason APFSDS rounds witbout the sabot have ridges running down their length. It allows a large surface area for the discarding portion to grab onto. Great video btw, never thought I'd see APFSDS fired from black cannon gun 😂 I subbed
a few things I see that can be improved: first APFSDS Penetrators and the Sabot have some sort of grooves that basically are supposed to do what you did at the end with the rubber band as well as giving the sabot enough friction the keep them on the penetrator before firing , second: you souldn't strip the sabot parts together to allow them to seperate easily after leaving the muzzle, and third: dont use that base plate at the back. you basically replace the actual sabot with that thing, which causes a lot of issues. Probably it also would help to try a material with a slightly better durability like ABS instead of the PLA.
Ditch the fins, use a solid cone 30-40 degree angle. Need to turn grooves into the shaft and have matching grooves in the petals. Lastly the front and rear petal supports need to be further apart to improve the stability
If you are going to use a plug behind the dart, you might as well build an APDS instead of an APFSDS, APDS uses a cup sabot which carries the sub projectile out of the barrel where it falls off. It's a way simpler solution to work with that doesn't require you to do fancy metal rib cutting you just it out towards the target, I think it will work at your ranges where it doesn't need to be spin stabalized.
Early APFSDS rounds used aluminum sabots for Al's lightness and rigidity. Might be worth a shot. Backyard aluminum casting's pretty easy (don't breathe the fumes or spatter metal on moist concrete!) and you can use 3D printed sabots to make sand molds.
If you keep your original sabot design but lengthen it to encase your fins with the penetrater lengthened to be slightly past the back of the fins to rest on the sabot it will protect the fins. Also adding a slight concave to the front of the sabot may help with separation. Using a heat resistant paint on the cracks will hold the sabot together but is fragile enough to break for separation.
Thanks! I’ve had a few people suggest sealing the surface too and I think that will make a difference for sure but I hadn’t thought about slightly sealing the inside together. Cool idea!
Yoh, I always think of using an APSFDS on a medieval cannon , see if the round will increase the cannons effectiveness. You did us a good service for this video 😎👍🇺🇸
I’ll share a couple of things about apfsds that I know if it helps any. Don’t add any spin to fin stabilized projectiles, it causes instability, I don’t know what your cannon is but if it’s rifled you’ll need to find a way to stop the spinning. You should find a way to attach the fins permanently from stronger material, preferably just machined with the dart itself from steel, aluminum would be too weak to survive the impact if you wanted to possibly reuse the dart. Don’t use a base plate you’ll only crush the fins, the sabot is your gas seal. Rib the shaft of the dart and make sure the sabot locks to them with matching dips, that will mechanically lock them together until they both exit the barrel so no need for tape or bands. Take a look at fully assembled apfsds rounds without the propellant case to get a better idea of what your sabot should look like such as where the engagement rings that touch the barrel are along the darts length for better stability. That’s all I can think of at the moment but I hope this helps cause I want to see this work!
Try encapsulating the whole round in a piece of pvc or some other tube with a foam insert. Cut it so it'll discard. You're problem lies in the sudden acceleration of mass. Use your disk at the base of your foam filled tube that contains your projectile.
The problem is the sabot petals and fins are being shattered by the force of the blast, the obturation you are using is getting blasted around the fins and petals Make the fins stronger, make the dart body do to the base, support the base with stronger obturator pads something that the dart metal won't penetrate. The petals are normally mechanically connected to the dart body you could do this with a few pins sticking out about 5mm each side about 5 or 6 at one inch intervals midway down the dart body.
Hey, it´s a great project but here is the thing, the pressure in the barrel goes through and around the Tpu wad, although it has a good seal, which causes the sabots to fly off the penetrator, which then can not be stabilized and just spins through the air. Also somewhere in the process, it shears off the fins. I would say try making the fins thicker and maybe try printing some ring that you can secure on the penetrator, that will ensure that the sabot does not fly off.
So turns out I was under the impression the base pushed the fins up and not the sabot pulls the rod and fins with it. That’s why the threads are there which makes total sense…
The PLA fins are never going to stand up to pushing that rod out the barrel; extend the rod all the way to the pusher plate, make the pusher [wad] out of a more rigid material [nylon perhaps] than TPU and then attach the fins to the rod. If you use threaded rod, you can screw a nut on near the front that will provide a rigid drive interface for the discarding sabot, and all thread is common and cheap.
While I'm not sure how the sabot works, I am positive that the needle and the fins should be one element. If the needle doesn't have fins, it won't be able to fly a straight and stabilised path, so for this part I would just weld metal fins to the needle.
![เปิดใจ “ต้นหอม ศกุนตลา” หลังโดนพาดพิงธุรกิจที่เคยทำ และผลกระทบทำถูกปลดฟ้าผ่า! | แฉ 24 ต.ค.67 [2/3]](http://i.ytimg.com/vi/vCi5OIqlxaE/mqdefault.jpg)
The finned dart sabot rounds have been some of the most difficult things for me to get to work and I'm dealing with half the scale you are.
You can't put a wad behind the fins because that will just crush the fins. The sabots double as the gas seal. Most of the darts we have tested (CanaDart, Anferov bullet, Dynaslug, and Sauvestre) have lugs on the shaft that match up with lugs on the sabots. Almost all the pressure acts on the sabots and pulls the dart down the barrel as the dart is locked onto the sabots. A common failure was when we tried to push the rounds too hard - it stripped the lugs right off and the sabots went flying at a high speed and the dart followed along at a very low velocity. The video we just did with the CanaDarts used very brittle 3d printed parts. I had to use a small 25 grain charge of Pyrodex and a spoonful of coffee as an inert buffer to fill the space. They worked OK but we were only getting about 500 to 600 fps.
It's great to see you here, i love both channels !
Colab!
Oh snap! Wow! Thanks for tuning in! I just recently found your channel and subscribed and your sabot dart made me realize that the rods were supposed to be threaded(and why 🤣😂) like two days before this video came out. I’ve so appreciated the knowledge that you share on how to cushion rounds and the ways you load them and the gas seal ideas. I hope you truly know how much I appreciate your channel and I didn’t expect this to even make it anywhere near a comment from you! I will for sure take your tips into account and get a working V2 version in the future. I greatly appreciate the tips and you tuning in in the first place! Keep making those amazing videos.
@@TheCannoneer One of my viewers left a comment saying you were having trouble with your sabot darts so I had to check it out. The viewer-created projectiles have been fun to do and I've been surprised at the creative ideas people have sent. People have been telling me that we need to scale things up to something like you are doing so it is great that you are taking that opportunity. The 12ga. stuff keeps me busy.
@@taofledermaus I was checking out the back catalog and there's some seriously weird things folks come up with. I have a hard enough time making a big round lead ball half the time!
Your problem is simple, the sabot is supposed to lock on to the penetrator and is used to accelerate the penetrator down the barrel with the sabot releasing and flying free once the penetrator exits the barrel. Your base was is crushing the stabilizing fins upon ignition.
I will admit I didn’t know why the rods were threaded but that makes total sense…
This is the correct answer.
@@TheCannoneerThey are ribbed*
for her pleasure
I was hoping someone said this.
Grooved not threaded but yes. This.
Your biggest problem right now is your APFSDS projectile is getting left behind by the sabots because there's nothing really holding them together. Real APFSDS rounds are held mechanically to the sabot by a series of machined grooves in the sabot and projectile locking them together. The sabot has the majority of the surface area and is where the majority of the "push" from the gunpowder goes and it pulls the APFSDS projectile down the barrel along with it. What might work best in your case is to make the metal rod go down to the base of the fins and have an additional base to push the projectile from behind. That way the majority of the force is the new base pushing on the rod from behind instead of trying to pull the rod from the front. You would have to redesign your sabot a little to make sure it could also hold up to getting pushed from behind, but that should be mostly making the rear section thicker.
You could also try printing your fins thicker and from Carbon Fiber TPU, which is significantly tougher against sudden shock and impacts while still being pretty stiff. It's pretty abrasive on brass nozzles so you would need to get at least a hardened steel nozzle.
I don’t know if I can print carbon fiber on my printers! I’ll have to look for sure! I was wondering what the all thread was about inside them but that makes complete sense. Keeps everything together.
@@TheCannoneer All you really need is a hardened steel nozzle for your printer(Short term) and hardened steel/replacement extruder gears(Long term) if yours are brass. If yours is a threaded removable nozzle it's almost certainly a standard size nozzle that's widely available anywhere that sells 3d printers and accessories. If its something more proprietary, like from Bambulabs, they usually sell hardened nozzles or may come standard on their high end models.
@@tu-jx6wh there are also tungsten carbide nozzles as well, they don't wear at all, they will basically last a lifetime unless you're extruding filament loaded with diamond powder, which I don't think exists...
The easiest answer for the rod is to make it from a threaded steel rod and have the three print sapo interact with that you could also easily machine a metal tip that you could then screw on to that rod
@@TheCannoneer Using a section of all-thread as your projectile might be a quick and dirty way for your sabot to retain the penetrator rod as it goes down the bore. Keep the sabot pulling by threading its inner section to match the rod.
1. Don't make pressure push on the fins with the pad
2. add grooves on the rod so the sabots have tight grip
3. Add aerodynamic surfaces on the front of sabots that will better push them apart after leaving barrel
- I really like your creativity 🙂
Sounds good and checks out
Much appreciated! I didn’t know these rounds were pushed by the sabot and not the fins when I made these but yall have wonderfully explained that so I was unknowingly putting pressure on the wrong parts. We will be a redesign and get these working! Thanks for the tips!
Here is an image of what Martin is talking about. I believe these sabots are normally split lengthwise into three pieces.
pbs.twimg.com/media/DmcwFhqVsAAGF3C.jpg
The sabot needs to pull the dart from the front. Not be pushed from the back. In all APDFS rounds from 7.62x51 DU to 120mm. The sabot pulls from the front.
It's also cupped at the front to catch the air and separate from the dart as quickly as possible after it leaves the barrel.
I'm sure people have mentioned the grooves normally found on darts so the sabot doesn't slip.
An interesting fact. Surplus 7.62x51mm DU has made it onto the civilian market. It's really rare but cool.
4. Keeping it subsonic also helps. Typical black powder shot is transonic -the worst possible speed for this purpose.
I've tested this kind of things with air rifles. Just a half gram piece of florists wire with rice paper vanes and a wood plug seal.
From a low power target rifle , ca. mach .4 speed, they work fine, consistently stick point first on 4" board at 10 paces.
From full power mach 1.2 vermin rifle they come out sideways.
Taufladermaus did a video like last week shooting some flechette rounds. It seemed like the sabot fully encased the flechette and had a cup shape at the tip above the tip of the projectile so once it's out of the barrel it catches air and splits instantly. I feel like that would work well here.
I shall have to check his channel out some more. I didn’t even know he existed until recently when y’all started suggesting it and he’s got some many cool designs! Thanks for the tip!
@@TheCannoneer Some think his channel existed before TH-cam......
He did have the test tube torture tests (say that five times fast) before he went totally to the shotgun ballistics@@clangerbasher
@@davidjernigan8161 I was making a joke. Nothing more.
@@TheCannoneer I was going to suggest that channel but figured you knew. The 12ga designs would translate well to your barrel I bet.
The other comment re a concave cup leading the sabot parts sounds right on. Clean separation
Oh man, a collab between this channel and Kentucky Ballistics would be amazing
My name is Jonathan and welcome to the Kentucky ballistics range!
@@TheCannoneer you really need a collab with the channel morecannonfab
1) I'd try a different 3d printed material- I've used PETG sabot rounds in my muzzleloader, they don't seem to break up at all (less brittle)
2) I'd try a softer wad- maybe felt layered or t-shirts layered
3) That penetrator needs to be nose-heavy and tail-light. The first 1/4-1/3 of the penetrator should be lead or steel, the body should be composite, and the fins 3D printed
Love this channel dude, keep up the great work! I hope these suggestions make it to you!
They for sure did! I’ll be sure to give some of them a try in the revisit and we will get these working for sure! Much appreciated!
Several people have made one suggestion of cupping the front flange as an air catch when it leaves the barrel the air will catch the fina pulling them away from the penetrator. But the biggest thing for stability is not using a pusher behind the penetrator. The sabot needs to pull the core out of the barrel. This is because without a perfectly balanced core any slight instability is amplified by the pusher. One of the easiest ways to get the sabot to lock in to the core is cut a small groove around the shaft of the penetrator. The with the sabot add a small lip on the inner diameter to fit into the groove.
On APFSDS, dart shaft's positive ribbed while Sabots' interior's negative ribbed so the sabot grips the dart shaft and doesn't blow out. Current construction is a soft "rubber gas check" then delicate plastic fins, then metal dart. On firing, the rubber and plastic fins probably give some or shatter. Maybe rag packing over powder then a short wood cylinder behind the dart as a rigid pressure bearing point. The solid shaft should carry all the way back to the bearing point - wood dowel -( the fins should end at the back of the dart). The sabots look sound, they only need center the dart, elastics alone should do. ..just a idea... besides, wood is cheap ! ..cheaper...
Good ideas! I was thinking about wooden darts and different materials if we got them working at all! Much appreciated for the improvement ideas!
@TheCannoneer Definitely check out how shotguns use a wad with a bit of spring-like material instead of a solid puck to push the round. It should help with the fins breaking on firing! Loved the video btw
@@charliegarrison9688 Thanks so much on both accounts!
Don't put wadding of any kind behind the fins, that's only going to load them and destroy them. Serrate the penetrator and have the sabot grip the serrations to pull it through. If spacing and a smaller charge doesn't help then you'll have to go with an all metal dart. Normally the fins are in the propellant explosion, they are NEVER pushed.
I had the idea of how these worked completly backwards when I put these together! Now I know why the threads are there. All thread on V2 for sure!
You're definitely crushing the fins.
Either metal fins or having the rod go right through to the back would be the quick and dirty solution.
Someone pointed out the TPU base is probably was just piercing a hole through and blowing everything apart in the barrel which makes total sense. I’ll have to revisit the metal fins idea and a few harder base plate materials….
Never would have I imagined seeing an old canon, be fitted with an APFSDS round 😅
🤣😂🤣
I'm sure if you were able to look deep enough, some unit from the Confederacy probably at one time said " Hey, y'all watch this".
@@jaxonboys3366this made me laugh
"My name is Jonathan, this is my canon."
Your intro have no right to go this hard
🤣😂 thanks!
steel fins welded might help and mayby an aluminium bore sabot. Cool stuff.
I’ll have to figure out how to get those working made!
Thank you guys so much for all your wonderful ideas on how to improve this round! We will get this working in the future with all of your improvements. Thanks for your support!
This might sound like a war crime do you think you could fire glass shards? Would be interesting to see what it does to a melon.
Love seeing this pop up :)
For a muzzle loaded apfsds you need a flat bottom piece that goes behind the flechete and support the sabot extrude a rod enveloping the flechete 30% of it is the base or the piston this is a single piece the remaining 70% is the sabot and you cut it in 2,3or 4 parts from the top and the head need a cup or c shape to catch the air to peal apart
And attach a pvc tube to the reloading rod so it doesn’t touch the flechete only the sabot
Edit and use paper strips to hold it instead of ruber or tape
And I don’t know if it’s will be useful but I shot a “apds” on my air rifle using a mold to envelop half of a nail in compressed wet toilet paper it works well both as a single solid piece or as a solid base and 2 peals apart mid ,it’s shrink a little wen dried but you can umidify (don’t wet it again)before shooting
Two options for making the penetrator better. Either make the overall length of the penetrator shorter or the fins longer. That would help it as far as staying on the flight path
I see good comments here. Mainly I would just make the discarding part of it a chunky cylinder that fills the bore and encapsulates the fins in addition to the penetrator to support everything as well as possible. 3D printing lends itself to chunky designs and your fins are too flimsy to be carrying all that acceleration by themselves. You might even see about adding a steel cross pin into the penetrator a little further up that can also key into the discarding sabot to take some of the stress off the fins. This would allow the sabot to pull directly on the penetrator taking some of the force away from the back. I imagine that even if the fins are surviving, the penetrator is getting driven back through the fins and through your TPU pushers like the penetrator that it is lol
Name the Segment “You Cannon not be serious”
I like it!
@@TheCannoneer try making HEAT-FS rounds next!
We now have "Taufladermaus" style content but with a Friggin' Cannon!! Sweet!!
Hopefully we get some weird rounds from some viewers too!
@@TheCannoneer If you want a shape that just WORKS, consider the "diabolo" air rifle pellet shape. It self stabilizes without spin.
@taofledermaus I printed one but I didn’t shoot it! I need to get some in lead and give them a shot one of these days too! Much appreciated!
Grape shot+multiple cannons+ flatbed truck= land pirates!
Revolutionary war technicals!
I don't care if your sabots failed, I instantly subscribed because of how you asked for feedback on how to get better. Keep it up dude!!!
Thank you so much! Y’all have given me so many ideas on how to fix them!
This sounds like an AK-50 style project that will become the core of the channel and will be solved in like 10 years xD
There's another guy on youtube called flasutie id hit him up and ask him for ideas since it's one of his specialties and he might be able to help i hope you get it to work and i can't wait for the next video.
Love that guy
I’ll check him out and see what we can make happen! Thanks!
Another channel worth checking out for ballistics is Taofledermaus. They’ve done some darts
taofledermaus is another good resource if you haven’t discovered him yet. He basically does the same thing just with 12 ga shotgun loads. There are several videos of “apfsds” rounds going through iterations to find what works. I imagine it would be a good resource since I think people have gotten them to work, though on a smaller scale with about the same acceleration. Idk how that scales to a small cannon though.
@@rofllcats I just recently found his channel since yall mentioned it! His loading techniques with the cork seems super handy and I will be sure watching more of his videos for some tips!
If you look at the tank's APFSDS, it's the back "bulge/ring" of the sabot that seals the case and is pushed by expanding gases (the front one keeps penetrator straight). The fins are actually inside the propellant when loaded. I think in your case those TPU disks simply push through stripping fins, because the penetrator is not supported well enough. Maybe redesigning the sabot in a way that it is pushed directly (so the sealing bulge/ring is behind the fins), and adding on the inside something that would grip the penetrator along its length would help. Anyway - great video.
That makes total sense and when I found one of those discs it did have a hole in it. I bet you’re totally right as to what’s happening inside there. I didn’t realize how those rounds really worked until y’all explained it and that makes total sense. We’re pushing from the wrong part and the stress is on the wrong piece. Much appreciated for the tips!
@@TheCannoneer yeah apfsds is really cool in its simple science. my countoured fin base cap idea was more of a solution geared towards your current design layout. but if you actually redesign entirely and aim for the proper shell mechanics i think youll see much more success and much easier than trying to improve your current one.
Watermelon.
Beautiful.
I love to watch them mistify….
For old school artillery, you need old school ammunition. Forget the 3D printed fins, just make a nice penetrator spike and fit it with a suitable discarding sabot. Bore a hole through the end of the spike and tie some hemp line with a monkey fist ball knot made a few thousandths shy of diameter of the barrel. Leave about 4 - 6 inches of line between the spike and the knot. Soak the line in water over night, this will keep it from combusting when fired. Ensure the monkey fist knot is still about the same size as the sabot outside diameter, dry it out a little if its swelled with water, coil the line to butt the knot up to the sabot then load the lot with a wad to keep the monkey fist off the powder. The ball should trail on the line when fired, inducing drag and stabilizing your penetrator. With some fine tuning on the size and weight of the rope ball, you should be successful.
I would also recommend finding the center of gravity of the dart too. You can do this by measuring the length of the dart and then suspending the dart by a single string at the measured center of the dart. Make sure you start with more length at first so you can cut it into the right length as needed. Do this properly and you’ll eliminate all tumbling after the dart leaves the muzzle.
early sabot projectiles used tapered sabots to act as a way of holding and pushing the projectile down the barrel
That first one would create a nasty bruise. Omg I love this!
Thanks! I’m excited to get a working version and see what damage we can cause.
OH YEAH
jsyk, real APFSDS rounds have ledges / steps on the penetrator that interface with some on the sabot, so the sabot actually drives the central projectile. here, the sabot may just slide off the penetrator during firing as there is no mechanical interface
I’ll have to take that into account and maybe use some all thread and the threads on the petals and see what happens!
@@TheCannoneer all thread is an ingenious solution. this solves your fin mounting porblem as well as the pedal to penetrator friction.
As much as we love 3D printed projectiles, they have limits as far as surviving violent acceleration as you would see in a black powder cannon. It's not impossible, but requires additional design improvements to prevent the projectile from being obliterated to avoid the plastic from being destroyed during firing.
Oh snap! Thanks for tuning in! You guys have great videos too! I’m hoping to get a working version with some of the tips everyone here has been suggesting. I truly appreciate you guys checking us out! If you guys are up from some exploding cannonballs…. Hahaha.
You might try TIG welding some steel fins onto your penetrators. You might need a jig to hold the fins in place wile you weld though, to keep the heat from warping them out of alignment.
Hah! You beat me to it! I've been itching to turn some custom tank sabot penetrator rounds for one of my cannons.
The sabot of the round itself is suppossed to be exposed to the pressure gasses, not a baseplate behind the round.
the fins were clearly not strong enough to hold all the force.
The problem with your round is that the sabot will get launched out without the dart if you had no baseplate. To fix that you need grooves on the dart and the sabot so they get locked together while still in the barrel.
That makes complete sense when you look at the cross section. I’ve got to make it work the other way around… as it’s being pushed from behind on the fins now. I didn’t put that together until now. Thanks!
Awesome video. 👏
Thank you so much for tuning in! I greatly appreciate it!
Make back side (feathers) from metal same and that's it!!! Simple!!!😊 Greetings from Serbia 🇷🇸!!!😊
Welded fins for sure on V2! Thanks for tuning in! I see your country a lot TH-cam thanks to Zastava arms and its beautiful from what I can see!
Failure is always a welcome option. Looking forward to the next set of tests.
I’d hoped y’all would still like to see the failure!
seen a lot of people saying this, but it's true. this dude really is the taofledermaus of cannons
He actually commented on our channel last night too! Dudes been a wonderful wealth of knowledge on his channel to load things. I just started watching his channel a bit ago but it’s so informative.
@@TheCannoneer yeah im personally subscribed, love his content myself
speaking of subscribing, the idea of shooting things out of cannons definitely piqued my interest, ive subscribed to you too :)
Coffee grounds are a good space filler for some of this stuff too
And they should be a soft shock absorber! Thanks!
I dont think the 3D printed fins are going to hold up to the forces involved.
An alternative design would be a yo-yo style to generate the spin. Sounding rockets use a yoyo to despin, but a modified design could also spin up the projectile. There are two ways. The first design is simpler, you attach a wire to the Sabot petals and spool the wire around the projectile. As the petals are flung outwards, they unwrap from the projectile, spinning it up. The second way would be harder but more similar to rocket designs, you would need to have some small weights on the end of wires with a slight rotation already present, if the wires are winched inwards to bring the weights closer to the projectile, the moment of inertia will decrease and the projectile will exponentially increase in rotational speed to keep the angular momentum constant. Having the wires pass through holes in the projectile and anchored back to the cannon or the sabot could winch the wires inwards if done right, the other ends of the wires just having some weights attached to them. The best way to think of this second idea is a figure skater pulling their arms in to spin very fast, the same principle will apply to the sabot if you can pull mass inwards to the center of rotation somehow.
You could also just try to make something more aerodynamically stable. The idea of the fins, besides spin stabilization, is to put the center of drag behind the center of mass. Alternatively, if you were to cast lead onto the nose of the projectile, it would be nose heavy and much more stable. Lead is over 50% more dense than steel, and very easy to cast. Real APFSDS rounds use tungsten or depleted uranium for the penetrator because of the increased density.
Bring the base of the steel to the base of the fins... Don't allow the fins to be pushed along the rod.
That seems like the first thing that will help for sure!
We asked for apfsds and the mad man actually delivered!
We will get some working ones here soon too hopefully!
Weld the fins on the rod.
I’ll have to see if I can get some steel ones!
Theres alot of good information in the comments to recap the main changes that you need to make if you want this to work
1. you cannot pit wadding behind the fins bc the fins cannot be made strong enough to be load bearing and will be crushed by the wadding
2. In a normal sabot round the petals interlock with grooves on the projectile and the petals are responsible for pulling the projectile down the barrel and obturating the barrel (thus taking the load of the fragile fine)
Also a note on terminology, what you refer to as the "petals" the parts the hold the projectile are called the "sabot", and the part you refer to as the "sabot" is the projectile
PLA is too brittle.
People's liberation army?😂
you popped up on my homepage out of nowhere...
I see cannon.. i see big poof.. i watch.. i like.. me happy
Hahahaha! Much appreciated! If you have any ideas about stuff you’d like to see let us know!
@@TheCannoneer i dont know if you have ever seen paul harrell and his "meat target" but id love to see you shoot a "human like" object with grapeshot so we could get an understanding of how deadly these loads were
Im 51 and the kid in me comes out watching someone firing different projectiles at targets . Whether they fire well or break up the explosion and smoke are enough for a smile 😃 😊 im a simple person 😅
Thanks so much! It’s a ton of fun even when they don’t work for me too!
First video of yours I saw I was like: " wow, here's another dude with some weird-ass hobby on youtube". Now every video of yours I am like: "WOW HERE IS THE DUDE WITH THE CANNON!". Subscribed.
Hahaha! Much appreciated!
I do like guns but i didnt know that i like antique cannons this much since i found your channel
I like both for sure but the bigger ones are a bit more fun I will say lol
I did 10 years in the army, and worked with munitions multiple times. What you need is a base that is the bore diameter, with a 3-4 part cast that fits around the projectile that us the bore diameter on the outside, and patches the projectile profile on the inside.
That baseplate disc is transferring the entire pressure load of the black powder charge to the fin assembly, and the damage is multiplied by the difference in weight between the fins and the metal penetrator. What I would do to redesign this is modify the baseplate and fin assy to where the baseplate disc can support the pressure load and transfer it directly to the penetrator rod, which seems to be the most difficult object to get up to speed quickly. The disc can be done away with entirely, however, if you cut a ribbed pattern into the penetrator rod and a matching one into the inside of the sabot so it can "grip" the sub-caliber round itself and so that the pressure load is dispersed into the sabot, which drags the penetrator and fins along with as it travels out of the barrel. You might also want to toy with the size of the powder charge. Too much powder means too high of a pressure spike, which means the sabot or baseplate disc would be more likely to shatter under the strain of such a sudden acceleration. I hope this advice is good enough to make a difference, preferably for the better.
I am all for this, and best of luck to this young man and look forward to seeing his videos in the future.
Thank you so much!
LOVE the smell of watermelon. You've created an outdoor air freshener. Looking forward to future vids. Thank's so much for posting.
Thank you! We’ve had a suggestion for a smell o cannon so I think that will be a fun video haha.
excited to see what you and the community get up to with this!!!
Me too! Y’all are half the fun and the ideas y’all come up with!
Our founders are smiling upon this video, shedding a tear of happiness.
🦅🇺🇸
You guys doing gods work.
Thanks! 😂🤣
Cylinder of balsa split lengthwise. Short small fins that taper flush after 25 % or so of the length of the penetrator. A couple of right triangle gripping grooves forward of the fins. And a minimal amount of Elmer's glue to hold everything together for a couple of yards past the muzzle.
A potato cannon bestowed this knowledge upon me many moons ago and it yielded great results after some fine tuning!
I just screen shot your comment and I’ll see if I can get some working! Thanks!
Hey, I just wanted to mention how awesome it is to see your channel blow up recently. Keep up the great work!
Thank you! I appreciate you being along for the ride!
Idea: Simply move the fins forward on the penetrator so that the very rear of the penetrator itself is what has the pressure from the pad instead of the fins.
This will be the simplest way to resolve the issue with minimal modifications.
I have some experience with similar projectiles from air powered guns. I suggest....1. put in a seal plate that will do 100% of the pushing of the projectile so little or no gas goes past. Allow your steel shaft to set on this plate to better transfer force. The pusher might need a steel washer face as the plastic will just shatter from the force. 2. put tiny pins and sockets in your petals mating surfaces so they can index against each other and remove any rubber bands when you load the assembly. 3. put a twist on the fins to spin stabilize. You might need to make your glue area longer because this will add a torque load to your glue joint. You might also reduces your power charge and slow everything down a bit until you get the thing working as desired.
Beautiful. I just screen shot your comment and that’s gonna be what I’m headed for for one version! I’m going to try a few different designs people have suggested but yours is wonderfully explained and make total sense if I were to make a redesign myself. Thanks so much!
I agree you need a steel base to help transfer the pressure to the rod, I Bellerive right now the sabot is being blown off before leaving barrel because of pressure
There are a lot of ways to make this work on your cannon, depending on what kind of materials and techniques you have at your disposal. for starters, as a lot of other people have pointed out, the TPU plug in this configuration is never going to work, not only because youre pushing the fins, which are certainly going to shatter no matter what plastic you use (even aluminium might be destroyed), but also because the TPU is undoubtedly going to be perforated by the rod unless you make it unreasonably thick.
An easy fix to this would be to make the rod go all the way to the rear of the projectile and using a metal plate in front of the plug, then the design of the sabot would have to change to also touch that plate such that the fins dont get shoved into them upon firing. another observation would be to remove everything holding the sabot together, perhaps some white glue can be used to simply hold everything in place, with the idea that it will immediately break apart by the shock of firing, since you definitely dont want the sabot to remain attached to the projectile.
A slightly more complicated solution can be found by trying to more closely mimic the way a real apfsds round works. by grinding/machining grooves along the penetrator and designing matching grooves on the printed sabot (ive seen threaded rods suggested, altho its an easy source of something with grooves out of the box, im not entirely sure if the features are large enough for the plastic to hold onto). depending on how weak the plastic turns out to be, those features might just strip off so youd have to use some kind of metallic insert on the sabot (im honestly not sure how youd go about doing that, maybe some steel sheets could be cut in the same cross section as the sabot and then glued on both sides of each petal (petal being the name of each segment of the sabot), and the printed part would obv have to be altered to make sure everything still fits in the barrel snugly and without gaps, perhaps the steel plate could be smaller than and inset into the print to avoid steel on steel contact in the barrel and make sure there are no air leaks (it would be rather difficult to make the flat sheet seal properly)).
The final overkill solution would be to make everything out of metal, with the steel penetrator and cast aluminium fins and sabot. with the previous solution there would be nothing protecting the plastic fins from the heat of the explosion so that might fail even if it doesnt get contacted by anything solid, either by melting or shattering, so if a better suited plastic isnt available metal might be the only way. to that end, id recommend lost wax casting, as that allows for the most detailed parts and shouldnt be terribly complicated, altho simple sand casting can certainly work with a lot of post processing. the fins can either be directly cast onto the steel rod (not 100% sure if it would work) or attached later, either screwed or press fit/glued on (obv only go with screwing if pressing fails). youre likely to need help with either process so id maybe try to find a local place that does casting.i certainly hope i doesnt come to this because working with metal casting is quite time consuming and dangerous.
Some final considerations as far as the general design goes:
>as i said at the beginning avoid holding the sabot petals with anything that could resist the firing process, like tape and rubber bands. altho they might tear apart its also possible they dont at all, too late or in an inconsistent manner, which could mean it messes with the flight path of the dart;
>the design of the petals can be changed significantly. this version that tries to mimic the appearance of the real one would probably only work in metal, with the plastic versions having to be significantly thicker to provide enough structural stability and strength. the real darts are designed in the way you see for several reasons: they need to be light (you dont want to waste the energy accelerating something that isnt the projectile), the contact patch in the barrel has to be minimal to reduce friction (the only contact is the seal at the back, which prevents the gases from escaping, and the piece at the front, which serves double duty as something to stabilize the projectile inside the barrel and to scoop the air after it leaves the barrel to ensure the petals release consistently and cleanly), it needs to leave space for the propellant charge (look up images of a complete tank round and youll see how the projectile sits very far into the casing), it needs to separate early and easily from the rod (this is accomplished by the aforementioned scoop). all of this means that if you dont need the utmost efficiency, several of those design considerations can be ignored and you end up with basically a segmented cylinder with a hole for the rod the pass through (and ofc the internal features to hold the rod plus whatever modification would be needed to accomplish this). some extra features that might help would be a taper in the rear (similar to the real one, altho less extreme), which would help squeeze the sabot into the rod by the pressure of the explosion (force vectors and all that), and the scoop at the front to help with the sabot release.
Finally, im just an idiot with a keyboard on the internet, so, altho i wrote as if everything was factual, do take this wall of text with a grain of salt (this was by no means an exhaustive list of everything that could be done nor guaranteed to be correct).
Much much appreciated for your ideas. I screen shot your comment and I’ll give some a shot! Thanks!
It seems like the main issue is the power of the Canon is pushing the fins of the Sabo through the shaft basically destroying the fins before it's even leaving the barrel to fix this it would be better for the shaft of the Sabo to go all the way through the fins
As a physicist, I'd make the parts that are supposed to come off into a cylinder just under the bore size. The cylinder would be long enough to keep the projectile perfectly aligned in the bore. I would put a thin, shallow spiral flute around the outside of the cylinder to impart spin (keeping the projectile accurate). I think i would try an inverted cone on the front of the cylinder that would theoretically be forced shut by the overwhelming presure of the blast (behind) until it leaves the barrel. I'd probably make it out of tpu. Summary:
1. Cylinder to push the projectile.
2. 2 halve
3. Inverted cone in the front to force the halves apart upon leaving the barrel
4. Rifling on the outside of the cylinder to impart spin (forget the fins; if you get this thing spinning right, you won't need em)
5. BIG ONE - Make sure the center of the cylinder is on the center of mas of the entire projectile! You know you've done this correctly when you can balance the entire projectile at the midpoint of the cylinder! This is crucial because it means it will have no force bias inside the barrel.
Much much appreciated! I’ll have to see what I can get into the works for everything! I’m not the best CAD designer sadly!
Penetrators don't spin because the rotational energy fights the forward momentum when it strikes a target, reducing the overall penetration depth.
At least that's what I've come to understand over the years.
And absolutely a sabot that fully supports the penetrator and centers it. It also has to grip the penetrator firmly enough to ensure full energy transfer, while falling away cleanly upon exiting the muzzle.
@@willabernethy4832 Fins stabilized anything shouldn't spin more than a few rotations a second to cut effects from tolerances on the fin unit. They're forward CG in relation to CP by design, and spinning a forward CG projectile can (usually does at some point) result in a coupling between aero stabilization forces and gyroscopic forces that end up positively reinforcing each other. You end up with a projectile that's spinning around sideways like a cheerleader's baton. Gyroscopic stabilization needs a rearward CG, which doesn't work with fins (wants to correct itself backwards).
@mfree80286
The jobs on the battlefield don't spin. Sabot rounds made to fire from old rifled barrels have ball bearings to engage the rifling and negate the spin. Today's smooth bore cannons on almost all modern tanks were developed specifically to fire sabot rounds more effectively.
Admittedly, long, thin, precise fins only a couple of millimeters in height are difficult to produce. Maybe long, thin grooves along the axis would suffice.
Something like a 15.1 length to diameter ratio is very important also when it comes to stability and accuracy
Either way, it's a lot of fun to figure out how to make physics work for you!
Almost 5000 subscriptions! Keep it up man. You cannot have enough cannon content
Thank you so much! Hopefully we can keep making some good cannon content!
I'll go with what the others have mentioned, the finas will never support being the part receiving the force, the penetrator needs a way to lock it to the sabot while in the bore, abd the fins need to be a tougher material.
I’ll get them working one of these days!
The sabot must be metal. Let me explain. If you look at the m1 abrams, the whole entire system doesn’t have any buffers between the shell and the casing. The sabot must also be metal if the projectile is metal, that way the cannon pressure wont make the projectile sheer off any metal holding the projectile in place. I recommend CNC aluminum, it should be strong enough, plus you can print it into whatever you want.
Edit: if not already, it should be properly held together on the inside. That way the projectile cant move forward or backward in the sabot, so then the sabot can cleanly release after the cannon fires and it has left the barrel.
Just a thought. If the casing were to not only cover the middle but wrap along the bottom of the fins for more grip that could encourage more of a solid shot. Once the back is out of the cannon there would be the air that could separate the shells and also potentially saving the fins. My biggest suggestion is to have metal fins. You either need to weld medal fins to the bottom of your rods. You can cast them in sand. But you really need to try to keep a total of 4 pieces. The 3 pieces for the shell, and the single stabilized rod.
I had a viewer send me some he designed with a full body cover so I’m excited to test those out!
Just sayin. I love this experiment. Definitely keep at it till you get it so we are ready to fend off enemies with black powder
For sure! I’m excited about trying a working one!
For starters your dart really should be better connected to the sabot. Remember your dart is absorbing next to no momentum itself, it has so little surface area exposed to the charge, it’s the sabot that’s built to soak up that pressure and spit down the barrel. The dart really only moves because of what’s imparted onto it by the sabot. This is why most tank rounds of the sort will have lugs on the inside of the sabot and outside of the dart, so the former pulls the latter with it. Couldn’t see well if there’s anything of the sort with your ammo.
Pretty cool video dude, I would like a second part
For sure! I’ve been working on some updates for a v2!
There’s several amazing collabs which come to mind
I’ll have to get to looking around!
@@TheCannoneer Get on Kentucky Ballistics and see if Scott can shoulder fire that cannon!
@taofledermaus already heard the calling !
Food for thought...
The APFSDS has grooves which lock it into the sabot. Maybe if you turned a few grooves into the rod, or use a peice of allthread, it may adhere better to the sabot.
Also, you need a pushing charge, not a forcing charge. Perhaps loading your cannon to the training load specs might change the pressure dynamic. 😉
And yes, pin the fins. They want for a mechanical connection to the rod.
I’ve realized that I’m trying to reengineer the design to be pushed from the base and not from the sides and y’all have wonderfully explained that to me which I much appreciate. I’ll pin the fins! If I’d have quite known how they are supposed to work I’d probably have done some rethinking!
That's... something I didn't expect, but YT suggested your channel! You get my sub and like, cause I like cannons. Cheers!
We do too as you can tell! Thank you so much!
Move the centre of mass towards front of the round. You can do it by providing draft angle to penetrating dart. Also increase the cup depth of seperator with through holes at each.
This is exactly the kind of science I expected!
Edit: Definitely suggest welded metal fins on the next test shots, in addition to the measures mentioned in other comments re: using the sabot as the pusher.
I’m gonna have to get those fins worked up for sure! Got a few different styles suggested so we shall hopefully get one working! So I totally didn’t know the petals pulled the rod and not the rod pushing the petals when I made these!
Simple guess, 'hide' the fins in the discarding part and make it so that the wadding pushes on the exterior of the round, not the final projectile.
Remember that on acceleration, every part of the projectile weighs several thousand times what it does at rest.
You cannot drive these from the PLA components. What you'll have to do is multifold and this is just an example of ways to make it happen.
1 - The rod will need to extend all the way back to the buffer disk, and you'll need to ensure the disk can't fold around it. A large washer may do.
2 - You cannot rest the sabot on the fins, it will crush them immediately. Drill the rod for a pin to use as a rest, or grind a groove that the sabot can interface with using half a washer embedded in the sleeve to spread the load. You could also add a pin and a small washer that stays on the rod to serve as a backer if you want to keep the current geometry.
3 - The sabots are not acting as a gas check or driving band in this setup, they do not need to be solid. Lighten them as much as possible by skeletonizing them. This also aids in aerodynamic separation. The only reason modern projectiles have this shape is the penetrator extends back into the powder charge and the sabot *is* the driving band.
I just saved your comment. Much appreciated! We shall get these working!
Oh. and.... the *easiest* way around all this is to make a cone tip that's wider than the rod, and undercut to serve as a notch. Then you can make a full encapsulation sabot from lighter materials, and the projectile will "hang" from the tip under firing forces, and then aid in pushing the sabots away as it leaves the barrel and drag takes over. As the part of the sabot ahead of the tip slides back it disengages the notch AND gets pushed sideways by the shape of the tip. You may need to add a couple angled pins or something to the sabot leaves to engage the notch and spread the forces around so it doesn't rip free, depending on what material you use.
Cool channel, glad the algo put it infront of me.
Thanks so much!
Try using a stabilizing cone instead of fins. Tank training ammunition is cone-stabilized rather than fin-stabilized. Without machining the penetrator to lock onto the sabot petals, that might be the most durability you can get out of this design. Also, ensure that your rear TPU disk ("wad"?) is applying pressure directly to the metal rod, and not the cone or fin stack. Mounting the cone or fins a bit forward of the base of the penetrator will help ensure that the bulk of the force is absorbed by the metal rod and not the printed part, which should leave aerodynamic forces after the round leaves the blast envelope as the only thing the printed part needs to withstand.
Hi, Just an idea that I have seen: Use a length of all-thread rod as the penetrator. You can then use a thread to locate the sabots and lock them to the rod. The gas seal is then on the sabot.
I just cut the all thread for v2 yesterday!
Really nice video quality with 4k hdr!
Thank you so much!
You need to create break groves and only have the thinnest pieces of material holding them together.
The tape & bands are flexible and do not break apart. You need to guide the break apart and weaken the material along those break up sections so the force of the wind is stronger and more than enough to break the material. You’d better off using a more brittle material like dried cardboard or very brittle plaster. You’re not using even close the power of a shot real sabots experience when fired so you need to compensate by using material that’s more brittle to get the proper break away affect you’re after
OMG you actually did it, amazing! sad that they didn't work. maybe having metal fins welded to the penatrator would work? Also nice voice over and always great camera work. If you get the APFSDS rounds to work ill send you a nice bottle of Dutch liqueur!
I try to make sure I keep my promises! I’ve still got the flechettes lined up but I can’t shoot them at our normal ranges. Only one will let us and it’s an hour from my house so I don’t get there often but they will be one of these days. I’ll raise you a glass on the working video one of these days hopefully!
The sabot is supposed to be the thing that absorb the energy. Make groves and sabot with groves to propel the dart. Also, use a 2 piece sabot with a air drag that would split it apart when it is on the air.
There's a reason APFSDS rounds witbout the sabot have ridges running down their length. It allows a large surface area for the discarding portion to grab onto. Great video btw, never thought I'd see APFSDS fired from black cannon gun 😂 I subbed
I literally picked up some all thread for v2 yesterday. We will get a working one sooner than later! Thanks for the sub!
@@TheCannoneer looking forward to the next vid 👍👍👍
a few things I see that can be improved: first APFSDS Penetrators and the Sabot have some sort of grooves that basically are supposed to do what you did at the end with the rubber band as well as giving the sabot enough friction the keep them on the penetrator before firing , second: you souldn't strip the sabot parts together to allow them to seperate easily after leaving the muzzle, and third: dont use that base plate at the back. you basically replace the actual sabot with that thing, which causes a lot of issues.
Probably it also would help to try a material with a slightly better durability like ABS instead of the PLA.
Fascinating, keep up the good work
Thank you! I’m excited to get one of these up and working!
Ditch the fins, use a solid cone 30-40 degree angle. Need to turn grooves into the shaft and have matching grooves in the petals. Lastly the front and rear petal supports need to be further apart to improve the stability
If you are going to use a plug behind the dart, you might as well build an APDS instead of an APFSDS, APDS uses a cup sabot which carries the sub projectile out of the barrel where it falls off. It's a way simpler solution to work with that doesn't require you to do fancy metal rib cutting you just it out towards the target, I think it will work at your ranges where it doesn't need to be spin stabalized.
I’ll have to look into those and see what I can come up with! I’ve learned so much from y’all since starting this channel!
Early APFSDS rounds used aluminum sabots for Al's lightness and rigidity. Might be worth a shot. Backyard aluminum casting's pretty easy (don't breathe the fumes or spatter metal on moist concrete!) and you can use 3D printed sabots to make sand molds.
That’s what I had in mind was sand casting some. We have a smelter for cans so it should be “easy” enough to try!
If you keep your original sabot design but lengthen it to encase your fins with the penetrater lengthened to be slightly past the back of the fins to rest on the sabot it will protect the fins. Also adding a slight concave to the front of the sabot may help with separation. Using a heat resistant paint on the cracks will hold the sabot together but is fragile enough to break for separation.
Thanks! I’ve had a few people suggest sealing the surface too and I think that will make a difference for sure but I hadn’t thought about slightly sealing the inside together. Cool idea!
Yoh, I always think of using an APSFDS on a medieval cannon , see if the round will increase the cannons effectiveness. You did us a good service for this video 😎👍🇺🇸
Thanks! I’m excited to get a working version.
I’ll share a couple of things about apfsds that I know if it helps any.
Don’t add any spin to fin stabilized projectiles, it causes instability, I don’t know what your cannon is but if it’s rifled you’ll need to find a way to stop the spinning.
You should find a way to attach the fins permanently from stronger material, preferably just machined with the dart itself from steel, aluminum would be too weak to survive the impact if you wanted to possibly reuse the dart.
Don’t use a base plate you’ll only crush the fins, the sabot is your gas seal.
Rib the shaft of the dart and make sure the sabot locks to them with matching dips, that will mechanically lock them together until they both exit the barrel so no need for tape or bands.
Take a look at fully assembled apfsds rounds without the propellant case to get a better idea of what your sabot should look like such as where the engagement rings that touch the barrel are along the darts length for better stability.
That’s all I can think of at the moment but I hope this helps cause I want to see this work!
Much appreciated! Me too and we will get one working!
Try encapsulating the whole round in a piece of pvc or some other tube with a foam insert. Cut it so it'll discard. You're problem lies in the sudden acceleration of mass. Use your disk at the base of your foam filled tube that contains your projectile.
I like that idea! Mythbusters style.
You should get a Slow mo camera in the future to really see what is actually happening.
I’m putting aside some $$ for one!
The problem is the sabot petals and fins are being shattered by the force of the blast, the obturation you are using is getting blasted around the fins and petals
Make the fins stronger, make the dart body do to the base, support the base with stronger obturator pads something that the dart metal won't penetrate.
The petals are normally mechanically connected to the dart body you could do this with a few pins sticking out about 5mm each side about 5 or 6 at one inch intervals midway down the dart body.
I’ve got a bunch to redesign! I didn’t know anything about these but we will get them working!
Hey, it´s a great project but here is the thing, the pressure in the barrel goes through and around the Tpu wad, although it has a good seal, which causes the sabots to fly off the penetrator, which then can not be stabilized and just spins through the air. Also somewhere in the process, it shears off the fins. I would say try making the fins thicker and maybe try printing some ring that you can secure on the penetrator, that will ensure that the sabot does not fly off.
Buttress threads on the penetrator and on the inside of the sabots.
So turns out I was under the impression the base pushed the fins up and not the sabot pulls the rod and fins with it. That’s why the threads are there which makes total sense…
The PLA fins are never going to stand up to pushing that rod out the barrel; extend the rod all the way to the pusher plate, make the pusher [wad] out of a more rigid material [nylon perhaps] than TPU and then attach the fins to the rod. If you use threaded rod, you can screw a nut on near the front that will provide a rigid drive interface for the discarding sabot, and all thread is common and cheap.
While I'm not sure how the sabot works, I am positive that the needle and the fins should be one element. If the needle doesn't have fins, it won't be able to fly a straight and stabilised path, so for this part I would just weld metal fins to the needle.
Great job in editing in some VO on the editing style. More dynamic, for sure.
Living and learning! Thanks!