Toroidal Propeller Testing on my Electric Surfboard
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- เผยแพร่เมื่อ 5 ธ.ค. 2023
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I have a weird propeller idea, it probably wouldn't be efficient but I've never seen it tried anywhere (probably for good reason) but I'd love to share it with you for the competition knowing I absolutely won't win......but maybe it can go in your weird idea pile, anyway I follow you on insta and am excited. I made it in onshape but I'm also terrible at that!
uuuugh, vaping! Why. This used to be a channel I'd recommend to my kids. Nope, not with this. Sorry. I've watched you since the start. Really crappy to see this.
Its more of an anti-vape than anything really...@@blaircox1589
One thing you never mention is the rpm. AFAIK toroidal props are only more efficient at specific rpm. I think it was 4500rpm in air. Sadly I don't remember the peak efficiency rpm for water.
@@rctestflightisn't it nicotineless
You should definitely use that V8 for another project soon. Nobody ever goes beyond just starting them up on their desk and letting them run. It was soooo cool to actually see it being used to power something.
Yea I totally agree! It would be awesome if he could make a hybrid system with it
naw EV is superior
@@throwawaypt2throwawaypt2-xp8nx Ain't nobody ask your opinion
@@URsooomad8613 facts don't care ab ur feelings ඞ
@@throwawaypt2throwawaypt2-xp8nx Not a fact, they're even more harmful to the environment. Try again.
Sharrow props probably dont have a negative angle of attack, the examples you're looking at probably rotate the opposite way you're considering. It's common on multi-outboard boats to have counter rotating lower units on the engine to correct for prop walk and other torques on the hull.
Also the blades themselves are different. His are all in line where as the Sharrow ones are offset from front of the blade to the back. I'm not sure how to explain that as i'm not sure what that part is officially called.
@@TheRogueBro Which part do you mean? I am not sure there is an official name for a specific part of a prop blade, even if its part of a larger "system" that reconnects to the hub, if thats what you meant.
The front and rear of each fin, on his they're parallel while on sharrows they bend away from each
Looks from here like the sharrows have more like a C-shaped fin, while the fins of the 3d-printed ones are more like a U-shape.
If that makes sense to anyone...
He keeps showing pictures of Sharrows and then making things that look nothing like them.
It's pretty annoying TBH.
I enjoy your RC related content, but I wanted to comment about the sponsor Fum. Fum and other similar products use essential oils for the "flavourings" and currently the long-term effects of inhaling them in this manner is not well understood with limited data. Fum's own "Science and safety" section contains two reports, both of which were commissioned by them and neither of which were peer-reviewed or published in any journals. As for whether they may be harmful with long term use is not for me to say, but I would encourage people to be sceptical of numerous claims made by them and companies selling similar products.
The whole commercial stuff in this vid, but also many other vids, looks ridiculous.
I'd hazard a guess that inhaling oil flavoured air, especially since it is not actively vaporized, is less bad than inhaling gasses released from burning stuff
You'd probably be wrong. Heavily processed oils versus some burnt plants.@@tktspeed1433
so what?
@@skipper1966why?
The search for greater propeller efficiency is admirable. Have you looked into the Hobie Mirage Drive systems based on fish/seal fins? I'd like to see you bring your rigorous testing to that type of propulsion some day.
These aren't necessarily designed for the highest continuous efficiency, but instead to make use of the most efficient muscles in the body, and in a way such that if you choose not to use it they are the least additional drag (as even a locked propeller is bad for efficiency, and a free-spinning one is worse). I wouldn't expect outstanding results that'll handily beat propellers due to this.
That said, I also agree it'd be interesting to see the result - efficiency tradeoffs can be worth it, and it would be good to know exactly what the tradeoff actually is.
Hi, i was considering the hobie system when I was looking into human-powered boat design. My conclusion was that the system is designed for mechanical simplicity, rather than pure efficiency, although the two often go hand in hand I don’t think that is true in this case. Basically the hobie system has a pair of fins (analogous to prop blades) that each oscillate back and forth along an arc. So functionally it’s a propeller that does a third of a revolution, reverses the pitch of the blades, and sweeps back the other way. There’s basically no way to make that as efficient as a propeller because you end up with a dead zone at each end of the stroke that gives you zero power. This is fine for human power as your legs have a dead zone with no power when you reach the bottom of the pedal stroke. But when you’re using a motor with (near-enough) constant power then that becomes a waste.
@@bit1564 In the comparisons I've seen, the Hobie system is far more efficient than a propeller. Basically you have two guys in kayaks doing a tug-of-war - one with the Mirage drive and one with a prop. Plenty of videos on YT about it. Also, the hobie drive is actually quite conplex compared to the well-trodden path of prop and shaft
@@iskierka8399 In the comparisons I've seen, the Hobie system is far more efficient than a propeller. Basically you have two guys in kayaks doing a tug-of-war - one with the Mirage drive and one with a prop. Plenty of videos on YT about it
He could also look into increasing hull efficiency. Maybe a bubbler like the earliest hovercraft designs could help reduce surface drag?
For your longer distance runs,You might want to try a rimdrive thruster. A rimdrive is basically its own motor with no shaft, the propeller is inverted without a center core (think of a donut with pointy teeth) in use they are practically weedless. I have seen video of commercial versions spiting out pieces of net that would disable a conventional prop. Weeds have to be the main concern on long distance autonomous missions, especially durring mid summer.
How would @rctestflight 3d print it though? I think he is pushing what can be made at home as well.
Two thoughts that occured to me were what effect would adding weight at the blade tips to create a larger inertia have?
The other is if he had considdered home chrome plating to increase the smoothness and add a minor level of impact protection?
@@RowanHawkins There was a company 3d printing them 5 years ago for small ROVs, I don't remember the company name
I have been proposing this too. Hubless rimdrives are so cool!
@@RowanHawkins Why couldnt he print them with his resin printer?
I would imagine the efficiency gain from toroidal props comes into play when you are at the limits of tip speed and the normal prop starts cavitating, so you gain a little bit of speed from a smaller prop. You usually want a prop that the engine is capable to rev up to max rpm (set by the manufacturer at which it usually starts cavitating and where the power peak is) for maximum power and so the engine has enough power to get it planing if its a smaller engine, this is not a problem with electric motors because you get instant torque
I love this design contest. Can't wait to see more videos of the deathmatch of props
Have you considered measuring output shaft torque and RPM in order to determine prop efficiency? In other words, remove the motor efficiency from the picture. This would make the comparison of the different propeller designs more general across applications.
sadly torque measuring sensors are quite expensive, in the order of 500USD or so
Bro never gives up in a good way
It's impressive that you can figure all this stuff out! You are so smart! I can't wait to see what you come up with next!
10:44 @MajorHardware 's "Fan Showdown" series version 2.0 and I'm absolutely stoked for it and the ensuing collab video.
your no-fat style of video editing is the best 👌👌👌
I went to school at University of Washington and watching your videos makes me remember everything great about the Pacific Northwest. I love seeing you take in all the great sights at Lake Union, Greenlake, or wherever you happen to find yourself. Great video, and I look forward to seeing more!
Which lake was in this video?
@@PimpinNProgress Looks like Lake Union
Old guy superfan here! After years of life experience, I assure you, you always get better results using a positive angle with the tip.
I just love your Boating and Propeller testing Videos. Thank you!
Oscar is a ledge, I learned so much when I was working with
an ODrive!
It would be cool if you did something like the fan showdown but for props, you would need some sort of indoor testing area with a way to measure thrust and power draw
Love the scientific approach and that you're willing to dive into topics which are often the point of the entire career of a dedicated specialist. You don't have to be as knowledgeable as a specialist to get a lot out of the experiments, and you could still trip over something nobody knows yet.
cute nail polish @11:31
that is a great video of scientific thought process,
definitely better then anything I had during grammar school or university
looking forward to your next video 🤩
I love the underwater slo motion shots of the propeller and thank you so much to making the propeller competition!
Your dedication is stellar.
nice iteration of the fan showdown. this will be sick
cant wait to see the next installment of these experiments, really like this prop design mini-series
Nice video, glad you've revisited the torroid
I'm hooked on all your boat related content, this is good stuff. Especially since it throws in my other favorite subject of 3d printing.
The negative tip bit was great.
I could watch a montage of the props spinning underwater in slo-mo all day. Its soothing watching the cavitation etc.
wooh its the fan showdown but propellers, i dig it!
Babe wake up new rctestflight toroidal propeller video just dropped
Love your scientific research videos like the data breakdown is my favorite 😂
Gotta love the Jetsons sound it makes!
Props.. this is a very informative an interesting video! Respect for your effort!
Interesting video and cool builds!
Oh boy, some competition to the fan showdown! Just in a very different environment.
Now you just need to find something else to use that mini v8 for
Love it! I keep smiling every time he starts because it sounds JUST like the Jetsons car XD
With your toroidal design the fins are behind each other, while in the pictures of Sharrow they don't seem to overlap like that. Maybe that improves efficiency
You are doing the science the rest of us wish we had time to do!
The prop competition is just like Major Hardware's fan showdown
Hey, notice the huge air trail from your toroidal propeller downstream of the bulbous center? And how it’s so much larger than the ones from the traditional propellers? That’s drag. And the shape has everything to do with it. Give it the same cone shape as the traditional propellers and you’ll see a fairly big change in efficiency.
I like this guy, he really smart
Lol the sup when it wheelied. Classic rctestflight
Doing a fan.. I mean propeller show-down? Neat!
Broski, your engineering skills are ace, but your shilling skills are scary good. Your ads are the best.
Propeller Showdown Season 1. Lets go!
I'm liking the rctestprop series.
First there Major Hardware's Fan Showdown! Cant wait dor RC Testflights Prop Showdown!
Thank you!
What a great way to wake up new rc test flight
I might of missed this tidbit, but what about measuring speed through water rather than over land? Current and tides variable can be eliminated. and you only have the wind variable to contend with.
His plot of (land?)) speed vs. efficiency is very well behaved. This suggests to me that the differences between land, air and water speeds for this particular experiment have negligible effects.
And while I agree with you in theory, there’s a long list of unknowns in this experiment that he could have eliminated if he had the time, money and computing power to measure. Good engineering is the art of making the most out of your limited resources.
@@owengrossman1414 At the midpoint of the craft, a flow meter, similar to what sailboats use to determine speed through water could be used. This would be a very simple approach. Sailing is a hobby of mine and the through of using movement through water seems a more plausible way to measure. I love this videos and this one I feel is quite provocative in this nature. Thanks for your responses. I feel these comments on this type of video can help us learn a lot more about this subject.
could you create a water 'wind' tunnel that is a big racetrack of water and then measure flow from each prop? Would perhaps allow for far faster testing of a larger sample of submissions.
Great video man!
I do think your results are still valid, but I noticed that the propeller boss is a different shape for the toroidal. Ideally, it would be best to control for that variable as well.
I literally have the exact same setup for charging bigger batteries, even with the y splitter as adapter between the power monitor and the battery. Glad to see that my jank is also his jank :D
YES! LOVE that we're going to get a "Fan Showdown" for props! shoutout @MajorHardware!
Love the R&D on this thanks power boat
Looking forward to the prop competition episode.
Very cool man. Superspeed.
Daniel, I enjoyed this video on propeller testing. Years ago, I was involved in designing a solar/electric boat for a collegiate competition called Solar Splash. The propeller design was critical, and we came to learn about the Wageningen Institute in the Netherlands. They were the leaders back then in propeller analysis. But in addition to pitch and diameter, there were other important parameters such as EAR (expanded area ratio), the airfoil shape, and more. I'm sure these also factor into the toroidal design. The best way to measure the efficiency would be to get a true measurement of the torque the motor is providing, which is not an easy thing to measure although you could build a cradle dynamometer if you really want to get serious. But if you can measure, torque, RPM, voltage and current, you could probably come to some meaningful conclusions. Keep up all the great videos.
I think it would be better to have a constant speed of the boat, then measure the power used over a set distance of travel. I think this would be the easiest and most accurate comparison because you eliminate the variable of drag from the boat moving at a different speed which can have a SIGNIFICANT impact on efficiency of the hull itself, making it difficult to know what contribution the prop really has.
Your videos just get better and better! Love to see your projects and it's fun to see where you test stuff since I live near Seattle.
Another really cool idea you could investigate (though I think it would be considerable more difficult) is wave-devouring propulsion. It would be sick to see that pulled off with your little Boston Whaler
some interesting results
Great video ! Question: how do you stay safe on the paddle board around all the big boats / ships ? You must be almost invisible how low you are to the water !
You should look at making a 3 blade prop but with cupped tips on the blades. Stops/slows down water spilling off the blades for more thrust. Also the there is a prop type know as the" chopper" where the top inch to 1 1 1/2 of the blade is cut off square.
I am a retired drag boat racer and have fooled around with some off the wall designs with the help of a pretty popular prop builder (Kindsvater).. Our props are nothing like what you are doing but this level of geeky? should have at least 1M subscribers.. Have no idea why but I like watching your videos....
Next foil experiements! RCTestunderwaterflight!
*Summary*
- 0:00 Sponsored video about propeller efficiency testing on an electric boat
- 0:06 Previous toroidal propeller designs were inefficient compared to traditional propellers
- 0:31 A third toroidal propeller design tested on a V8 paddle board showed superior performance
- 0:45 Converted the V8 paddle board to electric to collect precise data for scientific comparison
- 1:02 Designed and attached an electric skateboard motor to the paddle board
- 1:43 Tested various propellers, including a large B series and toroidal propellers
- 2:01 Found the toroidal propeller was efficient with electric setup, unlike earlier tests
- 4:18 Conducted proper propeller efficiency tests by controlling for power (set to 200 watts)
- 7:34 Used software to ensure the motor did not exceed 200 watts regardless of the propeller
- 8:15 Discovered that a 6-inch high pitch B series propeller was the most efficient for the test setup
- 9:34 Conducted an endurance test and calculated efficiency in Wh/km
- 11:34 Found out the paddle board could travel significantly far on a full battery
- 13:04 Performed Full Throttle testing, achieving higher speeds without a rider
- 14:18 Explained that a bigger propeller was too big for the specific motor used for testing
- 15:10 Clarified why the ESC setup affected initial propeller efficiency tests
- 15:57 Concluded that controlling for battery wattage provided more useful efficiency results
- 16:40 Acknowledged assistance from Oscar of ODrive for technical motor insights
Instead of the fan showdown, it's gonna be the Prop Showdown!
@rctestflight testing community propellers sounds like awesome idea. I'd like to see some 'bionic propellers' thrown in the mix.
you should try and make and test bionic propellers.
I feel like the unmanned board could be useful as an emergency lifeguard, since it can tread water much faster than a person could.
Also, I think you need some new Teva's. They're lookin pretty bare.
One big difference I see between the "MIT" props and the Sharrow is that the Sharrow is raked significantly aft so that the effective diameter at the leading edge is quite small, achieving maximum diameter near the trailing edge. I wonder if this may have something to do with the efficiency?
There 'was' a firm called 'Innerspace' that did ROV props, among other things. The guy that ran it was instrumental for reducing noise on subs. The props were a side gig done in a corner of his shop. - old family anecdote.
Phase current is a proxy for torque.
It was still a valid test for efficiency of torque to speed
I really want to do that prop design competition!
I know it seems simple but have you tried just using a simplistic acoustic resonance pump with piezoelectric? Or something similar? A larger into a medium into several smaller will be able to operate much more efficiently at specific speeds for the given input power.
Could you take a look at tubercle propellers? There's a guy on here called Robert Murray-Smith who's making tubercle fans and turbines, which is interesting. They take inspiration from the lumps on whale fins.
If you do another RC boat waypoint journey, then could you do a demonstration of how bulbous bows improve efficiency? I've always found it unintuitive that adding one massive lump to the front of a boat improves efficiency so much compared to a knife-edge.
If you expect to go through with the propeller contest, a bit more rules would be required. Something like @MajorHardware did with his fan showdown.
On a different note, would it be more fair to have a different gear ration for larger props, so they get more torque, but less RPM, while getting the same amount of power?
I love the idea of a prop design competition. Major Hardware did a similar competition with PC fans. Might want to check it out. He had some very wierd submissions.
I commend you for these prop experiments. I have a boat and it is over propped on purpose. It is cost prohibitive to increase power and torque to match it, and it is cost prohibitive to buy props to try to tune it. These props are Bronze, but if I could use lost wax and per blade resin printing to cast a replacement in aluminium alloy I could test without huge cost. Just substantial effort. One option might be to make the boat hybrid and couple a pair of Nissan leaf motors to the shaft directly after the transmission. Then we could get the RPM up in bursts assisted by those. Or putter around on only those silently. Or long distance with only diesel.
I noticed that there are big thick vortices at the propellor hub. Have you considered adding an aero-hydrodynamic 'nosecone'?
How about inner hollow propoller blades that you can stream air out. The bubbles comming out of blades would reduce water resistance. I saw them use in Navy
propeller design contest is this the new fan showdown contender
All credit to you and your efforts rc ! Keep it up and really like the freshness and immediacy of your approach. Given the potential of your influence, and for the sake of your safety in case you get tossed, would really like to see you wearing an LJ and set a really good example!!!!
Finally, a Prop Showdown
Tubercle propellers next!
Another option for testing would be to fix the speed and measure/log the current draw.
It might be interesting to do this at a few different velocities to see if the data is linear and if not, perhaps curves will intersect?
its always a great day with @rctestflight!
There was a study recently that explored a more jagged design of props, mimicking whale fins with barnacles. I’d be interested to see how those performed as they’re supposed to cut down on underwater noise.
Have you tested any nylon model aircraft propellers? I have found these to be the best of all on a Canadian canoe powered by a small electric motor running directly from a solar panel. There is one problem they have: they easily entangle weeds that are in the water.
You should try some Bionic Propeller designs!
People at the marina wondering what’s happening. “Ohhhh, that’s just Daniel. No worries!!” 😂🤣👍🏼
Id be interested in seeing what kind of things you could come up with using a Water Jet Thruster
I'd like to see a 2 kw waterjet jet on that paddleboard!
Jet impellers are really easy but the straighten-squeeze bits are a bit tricky. A dude called Xjet devised a four hole output that prints easily and works really well (less wall friction than vane designs). This design also allows the motor to be mounted at the back of the unit without a shaft and bearings being needed. The four output holes wrap around the motor.
Your ads are amazing.
love the vids post more keep the vids comeing i love this channal
You need a test cell! If you keep going down this rabbit hole into propellars, which is totally cool, you need better testing and data collection for how many props you are making.
I have a few suggestions. I might suggest getting one of those large metal pig troughs at your local farmgoods store to put in the backyard or garage for testing propellars. I might mount a motor/prop assembly at the bottom of a swing arm mounted to the top of the water trough, so that the arm hangs down into the water. You would then run the motor/prop in the water and have the arm pull on a force sensor, then convert that force to find the force exerted by the prop at the end of the arm. You should then divide that force by the power you are drawing to get a specific unit, like newton/watt, that you can use to compare everything, like even high speed and low speed efficiency for different sized props at different speeds. I can't think of a way to convert that to water speed somehow, but I would be very interested to see comparisons between low speed and high speed efficiencies, since I vaguely remember that ship's fuel consumption increased ^3 with speed. Was that equation only for vessels moving through the water, or does that cubic fuel efficiency equation count for propellars too?
On the test cell arm, you should pick a motor assembly you like very much that is well made and replacable, then don't change it, for repeatability. I wonder if you could couple the test motor to an identical motor and read the power produced on the other side, like a dynamometer, to measure losses in your motor to compare different speeds or different motors. You could also use the test cell to measure parasitic losses from linkages between motors and props. With a test cell, you could use a bench-mounted power supply for your test motor, like they have in school, for better consistency and to be easier for data collection on power draw.
I think it is time for a good test cell, maybe even one that could double as a hot tub - that reminds me, use the same water temp between tests, for conistency with viscosity. A good test setup will make it easier and faster to compare prop designs and dig deeper into the subject with better results. It would be a good for a cheap winter time project too. Then, I'd love follow-up videos to get comparisons between force per watt versus distance traveled out on the open water. This method would also make it easier to compare drag created by different boat hulls.
I love your show, man. I watch every episode when I see them. Your cadence, filming, and editting are on point, don't change anything like that. Just keep doing neat shit like you always do, and you're gonna be great.