"Established Titles" 1. No land ownership 2. No legal name change 3. No proof trees planted in Scotland 4. Pricing indicates product is real D) 5. Upon checkout, buyer is automatically subscribed to a monthly fee 6. On website, they talk about no land taxes in Scotland, inferring you own the land 7. Company owns two other brands linked to scams 8. Company lists an office in Scotland but no office exists, they are in Hong Kong 9. Company personally attacks critics 10. Ads use words "legally", "officially" and "formal", none are true 11. Website verbiage changed after being accused What else does anyone need in order to realize this company is predatory and highly unethical?
The Line through the Clouds is called a Distrail - or dissipation trail, the opposite of a Contrail - or Condensation trail. Both have the same cause - heat and condensation nuclei from the engine exhaust creates localized areas where the water vapor is condensed into tiny ice crystals or water droplets. In the Distrail- the effect creates larger droplets from already condensed mist (the cloud) which are large enough to fall away, leaving an open lane in the cloud.
No, it happens when the plane is sucking up water to mix with its stores of dry chemicals, so it can continue in its mission to leave chemtrails. You know, to poison us or drug us into submission or whatever it is the nutters say they're doing.
My 5 cents about sharp foils: recently I dove into hydrofoils thing too, designing impeller blades for waterjets. And when I was about to use some basic airfoil I suddenly found the airfoils for water are actually different (surprise) from airfoils for the air. The main reason is the cavitation. And the other reason - much higher water resistance: many hydrofoils do use sharp leading edge. Anyway - within working range of allowed angles of attack (usually something from -13 to +13 deg.) the sharp leading edge works ok.
Was about to say that, due to the viscosity of water, a sharp leading edge is better. Look at boat/yacht shapes the sharp edge is at the front, contrary to airplanes where the sharp edge is at the back.
@@pawelrelidzynski680the sharp bow angle on boat hulls is meant to reduce the bow wave created at the interface between the air and water. Torpedos and submarines use rounded fronts because they are fully submerged
@BlueIron64 i get your point, but that is not entirely true. You can see some bigger ship types being rounded in front and thats due to the speeds they travel. In water there is less resistance with a pointy shape in front, and i have seen it in a controlled environment. Same with air, less resistance when the frontsurgace is rounded and pointy in the back
"Established Titles" 1. No land ownership 2. No legal name change 3. No proof trees planted in Scotland 4. Pricing indicates product is real D) 5. Upon checkout, buyer is automatically subscribed to a monthly fee 6. On website, they talk about no land taxes in Scotland, inferring you own the land 7. Company owns two other brands linked to scams 8. Company lists an office in Scotland but no office exists, they are in Hong Kong 9. Company personally attacks critics 10. Ads use words "legally", "officially" and "formal", none are true 11. Website verbiage changed after being accused What else does anyone need in order to realize this company is predatory and highly unethical?
It’s because people don’t actually look into their sponsors. I’m surprised it took so long for someone to look into it and find what’s wrong with it. Although we will give this guy a little slack since the expose was about a month after this video was made.
@@fluppet2350 slack or no slack, it indicates he didnt look into his sponsors. I came across this company years ago and thought it seemed cool, but after a 20 minute google search it was clear they werent legitimate. Whatever "expose" happened recently wasnt necessary to see through their ruse
a little suggestion for the drone that went in the water: spraypaint the waterbottle a bright color so its very easy to spot when upsidedown in the water like that or fill it w/ expanding foam, so incase it is damaged it does not sink whilst also being more visible
Good suggestion. As color I would recommand a bright orange or red. If something samller would be wanted maybe the mechanism of an automatic life vest could be copied.
Also, a small LED light inside the bottle would be a good idea. It doesn’t add much weight but will provide you several hours of super accurate positioning.
The transition from hydrofoil lift to flight on the Regent aircraft seems to depend on a pitch-up "launch" to get more lift by increasing the angle of attack. While this might work, passengers might find such a maneuver more than a little unsettling.
@@XenoWiz more motors actually generate more power than a single big motor due to tip speed limits. If your tips start hitting the sound barrier they won't generate as much thrust and will generate a ton of drag. As such you can run a smaller motor at much higher speeds and have more of the blade in the "optimal thrust region" For electric motors having a bunch of smaller motors has major benefits, the first being that you don't need to put huge amounts of current through a single wire (fire hazard). The second is for motor cooling, third is cost (a bunch of small motors is cheaper than a single big motor). The Blown Wing isn't a new technology, it's been used for decades on drones and has a long history with STOL. It actually does work since the effect of the wing is independent of the ground this allows for a functionally higher airspeed over the wing than your actual groundspeed, it's like taking off into a headwind. Momentum is conserved since the lift and thrust are (mostly) perpendicular to each other. The reason why airplanes traditionally favoured having one or two big engines is because that was also their main powerplant. ICEs are big and heavy, their power to weight ratio is actually very low compared to electric motors (batteries and fuel not included). Gas turbines have a thrust to weight ratio comparable to electric motors. So why aren't electric motors used in aviation as much? Well batteries are heavy, much heavier that fuel, and that tends to be the deciding factor. And jets generate just so much power so easily that it's kind of dumb not to use them despite their complexity.
Yeah, you dweebs are just noticing a particular movement of a test vehicle and trying to extrapolate it into an inescapable aspect of the final product’s operation. Nice try dorks. The reason why the flying boat has hydrofoils is exactly to *prevent* what you geniuses think it will cause; jarring vibration/shock. A normal flying boat rides on the surface of the water, planing before it rotates. That means that the roughness felt by the passengers is directly related to the roughness of the water’s surface. If a seaplane has hydrofoils, it can quickly lift off *above* surface irregularities, causing a smooth ride as it builds enough speed to rotate. The only time you’d feel the rough surface/waves is at initial acceleration stages when the speed is low and affect on the airframe minimal. Basically a little rough right at the beginning, then transitioning to an incredibly smooth hydroplane affect, followed by a rotation that I’m sure can be modified in it’s severity. They probably just made it look like it was “jumping” out of the water for a cool promo video. Y’all really need to look at the big picture, how the entire machine operates, and not just autistically and pedantically notice one single aspect and think your assumptions are that of a smart person….
I've gotta say it's really nice to have someone to watch who just researches and tests things for the fun of it, it really keeps me motivated to just work on things that I think are interesting
In regard to what you mentioned on the jet. Why wouldn't skis be the ideal solution to most of these problems? At low speed the waves aren't an issue on the hull. At higher in water speeds the skis will plane, lifting the body/wings away from the waves. And then at highest speeds, when your airborne, then the skis could be retracted like landing gear against the body for a smooth hull. This seems to give you the best configuration for all three speeds for takeoff/landing transitions.
Skis would induce a lot of turbulence and drag but yeah if they were retractable it seems like a good idea. I just wonder if they would really help ekranoplans with the choppy water problem because they wouldn't be very useful at cruising speeds?
You're so knowledgeable about flying and boating that it makes the episodes fascinating to watch. I like when in some episodes you get super excited. It feels infectious! 👍🏻
Hi! I was so happy to see my mug in the "instigators' list" 😊 Thank you so much for making all the research and the tests. As you suggest in the discussion, hydrofoils would need to be short and possibly retractable (although they provide a tiny amount of lift in the air too, with some added instability). The goal is to leave the water as soon as possible to make the transition to and from airborne as fast as possible, especially in choppy waters -- the goal is to fly over the sea, which is *never* flat, even in a cove. From what you show and the Regent experment (I wasn't aware of this one), you'd use T-foils as they seem to provide more lift and less drag at low speed, and more than just one at the front spread around the CoG (i.e 1 ahead and 2 on the sides behind, or 2 and 2, adding to the same surface). Currently, I'm more on the Lippisch design (inverted delta) with 12º anhedral to which I add canards, the idea being to add 1 hydrofoil under the fuselage and 1 under each of the floats located at the ends of the wings, so to transition as quickly as possible to airborne. So far, the canards are attached to a nacelle at the front (like big ears on the head of a flying duck) because I wanted to have wings swept 30º forward (making an skirt open 120º in front), but I probably drop that to no-sweep and have the canards attached to a straight edge so to modify the entire wing geometry by moving the canards'edges up and down. Thank you again for all the work and the actual experimental results you provide. Keep up the fantastic job!
This is the video I've been waiting for for ages! Your closing remarks are the most valuable to me: 1) Hydrofoils could help get GEVs and seaplanes out of the water, and perhaps aid in landing. 2) They'd have to be retracted to make efficient use of GE. 3) This bonus is not present at RC scales (likely due to smaller mass to surface ratios and lower Reynold's number). This had indeed been my hunch, but I'm so grateful to you for actually doing these tests and giving your expert's opinion. My motivation for the idea has always been the tell-tale fact that the Ekranoplan allegedly used 8 turbines to take off but only 2 for sustained flight. Perhaps one could also improve efficiency at sub-takeoff speeds by propelling the craft against the water rather than the air - e.g. by a mounting a boat prop to the back of the hydrofoil, or by creating a water jet with water sucked in through a hollow foil.
Just to save you some money in the future: the steel you buy usually isn't hardened, so high carbon steel isn't harder than regular steel (mild or construction steel) unless you actually temper and aneal it. Not that it matters a lot in those quantities, but tool steel is about twice as expensive as mild steel :) Additionally, brazing might be a better (easier) way to to attach pieces like that without sacrificing much strength. Anyway, awesome and educational video as always!
PSA: Be cautious about what craftsmen/tradesmen tell you about heat treatment. Many of them are notorious for getting it wrong because they tend to learn by word of mouth and trial&error rather than reading about material science. And we all know how the game of telephone tends to go. Heat treatment is a science. A branch of material science, to be exact. And it's complex enough to require highly educated and dedicated specialists when doing R&D for big expensive projects. Anyway, annealing undoes tempering, and tempering improves strength, not hardness. Quenching fast makes it hard, though also much more brittle. Tempering reduces brittleness whilst retaining higher hardness than other processes, which ultimately increases its' overall strength. Coincidentally, that metric is called 'ultimate strength', which is different a completely different metric from 'hardness'. Look up the tests for measuring those two. Annealing is the process which kind of 'resets' steel, typically used to maximize machinability (make it softer/more easily workable) and remove internal stresses due to forging and machining processes. It's also typically quenched more gently so you aren't left with an overly-brittle product.
Outstanding! Thanks for teaching me about ventilation. Never heard of it before though I've seen it before while not recognizing it as anything. Amazing footage between the drone and the ground effect "napkin"!
Just a gut feeling - when there is no physical connection between an air cushion vehicle and the water, there must be less drag than if you dangle some shape, any shape down into the water. Your interesting experiments proved just that. The air cushion principle is so elegant in its simplicity. One hypothesis I'd love to see you try is fencing - i.e., Run a raked vertical fin down into the wateron the rear inner faces of your sponsons. Seems to me that you could extend the cushion of high pressure air further back, negating form drag from any horizontal surface touching the water. My theory is that fins would yield two benefits - first, lower form drag, and second, better lateral stablility. I'd love to see you throw some fins on your mature research aircraft!
you should look into supercavitating hydrofoils. I reckon you'd love em! Im currently developing one for a high-speed foiling windsurfer down here in the choppy waters of the Swan River
16:20 looking at it, I'd say that it's almost certainly possible to land it without stalling at 52kts-- taking off would be more difficult, but the ground effect should help it reach the speeds it needs (for example, in soft field takeoffs, we lift off much sooner by applying full back elevator pressure-- however, once in the air, we immediately let off pressure, and stay in the ground effect until rotate speed). I'm pretty sure that plane's wingspan is long enough that it can be in ground effect without the hydrofoils being in water, so I imagine that's how they'll do it.
if you have a multiple stage hydrofoil: the bottom one, smaller, pulling down, and a bigger that would skim the surface, perhaps with a mechanical 'feeler' that would auto-adjust the height?
Great video! I'm curious, have you tried a "fan wing" design before? It would be cool to see if you could combine the ground effects stuff with the supposed "ultra-high efficiency" and short take off distance that the design proposes. They're not capable of high speeds nor high maneuverability, but I'd like to see how efficient they can get.
The reason why the flying boat (Regent) has hydrofoils is to prevent jarring vibration/shock; A normal flying boat rides on the surface of the water, planing before it rotates. That means that the roughness felt by the passengers/airframe is directly related to the roughness of the water’s surface. If a seaplane has hydrofoils, it can quickly lift off above surface irregularities, causing a smooth ride as it builds enough speed to rotate. The only time you’d feel the rough surface/waves is at initial acceleration stages when the speed is low and affect on the airframe minimal. Basically a little rough right at the beginning, then transitioning to an incredibly smooth hydroplane affect, followed by rotation. It actually makes a lot of sense. Same thing with landing; land on the hydrofoils, then by the time the plane decelerates enough they don’t generate enough lift to lift the airframe above the water, the plane is going slow enough that the rough water won’t be too abusive to the airframe.
There are hydrofoils that use supercavitation. This is just forced cavitation at higher speeds and can increase both top speed and efficiency. I think the largest benefit to adding both ground effect and hydrofoils into one vehicle would be it’s very high weight capacity; high weight would also help with the foil staying close or in the water… last thing, foils can also be used to pull the craft towards the water preventing the bouncing created with ground effect.
Daniel, I am always amazed at how much science and education you pack in your videos, but ngl my favorite part is always the music videos at the end. So lucky to have your own personal musician! :D
Hello, I am an embedded systems and aeronautics engineering student and I think you can keep the hydrofoil in the water by increasing its surface by making it longer but also larger. u could also place the rotors behind the aircraft (like the sr71 for example) and move the hydrofoil more towoards the nose/front of the aircraft. so the thrust is coming from behind and its helps stabilisation, or even better ur can do the opposit keep the rotors in front and bring the hydrofoil more the back you should try it actually it could be interessting keep in mind that performing these two ideas might introduce the need to add a variable angle hydrofoil for way better stabilisation !
Mr Daniel, I'm glad to see you again in my top video suggestions, its been a while. :) Hey, also, thanks for your previous videos on the auto gliders and solar planes etc... I'm almost done building up my ASW 28 for the auto soaring via ArduPilot, same as you did. Keeping on doing your thing, its top tier!
You don't want a super low wing if there's any chance of chop. I live on the SF Bay and I want something to scamper from SF to the houseboat and back again. It's only about 5 nautical miles and sometimes the bay is calm, sometimes it isn't. Lots of hydrofoil options but ground effect seems to be a better overall choice - higher speeds, lower drag, likely better efficiency. I'm checking this out as it seems to solve the transport problem. Ground effect plus hovercraft means I can land on the beach or in the harbor. I'm also a Tesla Sr engineer and would want to EV convert it as a single Tesla motor is about 220kw, way more than needed for this application.
I think there might be a way past this with the full-size. Why does it cavitate? It cavitates because you're changing the direction of the water with the foil in order to achieve lift. If you were able to adjust the angle of attack dynamically, you could adjust it to zero, which would minimize cavitation and drag and eliminate lift at high speeds, or adjust it to steep, which would allow for high lift at low speeds.
Wonder if having a different wing profile would be better for hydrofoils, maybe even capturing the ventilation/cavitation air bubble and using it for lift. I know there are some boats with flooding compartments (flooded when not moving, for stability. Empty out as the boat starts to move for higher speeds.) Applying this concept to a hydro wing make me think of basically one with a front slat, but the slat is attached at the bottom. Or just a channel slightly behind the top of the wing profile. My thinking is that at speed this would create a pocket that would either just help with lift, air is lighter than water an all that, or serve as a vent to bring the gasses along the foil and out of the water, away from the wing itself.
Please dump sponsors like Established Titles (others that come to mind are Kamikoto or RAID Shadow Legends). They're effectively scamming people out of their money. Sure, it's only a novelty gift, but charging 50+ dollars for absolutely nothing (maybe a single planted tree) is still a scam. Kamikoto is actually part of the same parent company, although they sell actual products under false pretenses (shitty mass products that they claim are handmade quality products).
Actually, the stagnation point does not remain static with changes in angle of attack. As the angle of attack increases the stagnation point moves backward from the leading edge, on the lower surface of the wing. At high AOA a small portion of airflow on the lower surface is inverted, spilling forward and up from the high pressure under the wing to the low pressure above it, and you can easily test this with smoke tests in a wind tunnel or with short tufts attached to the leading edge of the wing.
Someone may have mentioned this but there are hydroplanes that use cavation to produce lift. They have sharp leading edge with square traling. The fastest sail boat uses one.
I always thought about building one of those, except my concept was sort of a airplane with legs where the lifting body (passengers and pilot) is in front and the waterski/foil part (power source) remained attached to a surface on a sled.
About the Regent Seaglider - their prototype also has wingtip pontoons whose holders (not sure of the technical term) prevent the air from escaping sideways and thus increase efficiency. For added bonus, I suppose they act like winglets and help in airplane mode as well. Not sure why they don't have them in the final design. Plus, as mentioned - high wingspan helps keep efficiency even if the wing absolute height is... well higher. Which, in turn, helps operate in rougher weather. Reverse delta ground effect vehicles can also get away with higher wings (at least their leading edge). Also not sure why we don't get more of these.
Based on my experience in sailing hull design, I wondered if making a V hydrofoil would help with the transition from air to water. A more gradual "entry". I also was listening to an AC foiler Catamaran discussion, where they noted that any vertical surface entering the water, induced air down to the foiling surfaces, and created cavitation. That diagram showed foils entering the water with Dihedral angles, :1:57 - "Surface Piercing" instead of straight down. "Fully Submerged" Those two category's at :1:57 are deceptive. ALL foils are Surface Piercing, unless you are a Submarine.
Just a thought on turning a ground effect vehicle. Since your essentially flying flat, your tail section should steer like a car linkage. And, the front wing on the inside of the corner should create a small amount of non lift creating drag. Kind of like breaking one wheel on a car to make a tighter turn, but just slightly. Anyway, that was a fantastic lesson.
Fascinating video. Essentially the lack of water pressure differential in the couple of inches the foil pierces the water for a model robs the model of the lift increase provided by the feet a full-sized foil pierces the water. The main advantage of the hydrofoil is the ability to maintain a higher speed in moderate sea conditions without pounding the passengers into jelly, as would happen for a planing hull. For a model, ground effect just seems better, as long as you get enough altitude to avoid the waves. Which is why experimenting with multiple foils is probably just a waste of time.
Excellent video as always! With regards to the use of hydrofoils, Regent are selling their addition as a different phase they can operate in. Ie they can operate in an area close to shore on the foils at relatively high speeds without the wake. When they then get out in the open they can proceed to flying. Rather than solely a way to get the craft out of the water more efficiently. The thing to be concerned about with foils is the possibility of ''hooking' them in the water at high speed as happened with the X114. The Seaglider retracts them to avoid this. But there is still the concern about the conflicting aerodynamic/hydrodynamic forces/moments between foil and wing lift. They are very hard to marry up.
Great take on an interesting area of developemnet , The Americans spent a lot of time on foils on seaplanes ,in the 1940s ,not a lot came of it ,I now see why maybe . An Aussie guy has gone water ski waywith his boats, 'sea ski', may be the best solution for a lighter 'water form' for amphibian and sea planes . Of course modern materials can make lighter stronger hulls too .
Hey I'm in a video, cool! Thanks for the mention. Excellent exploration of the concept! It's cool to see the historical applications of the tech, so thanks for including those. Ventilation is the WORST when winging, I think that's the appeal of high dihedral front foils, although you rarely see it in rear stabilizers. I'm sure you've done plenty of research while making this thing, but if you want to get into hydrofoiling, there's plenty of money in the industry now, particularly wingfoiling, since it's the new hot thing, so lots of watersports companies have been investing in research to create the best hydrofoils. It's neat to see the differences in performance, high/low aspect, lots/no dihedral, thick/thin wings. I was toying with the idea of creating a biplane style hydrofoil, where the lower wing is smaller, creating less lift, but less drag to provide a gradual transition to flight, but you've proven pretty well the combination with ground effect aircraft isn't super compatible. Well done, keep playing!
Have you considered trying a water rudder with one or two vertical fins to provide horizontal force? You never seemed to be able to turn too sharply while in ground effect, that could give you some much sharper maneuverability.
Excellent stuff! I reckon skis with suspension are a better match to GE. No finicky stability issues, no ventilation or cavitation, no weed or flotsam issues. I'm pretty sure now GE is a bit of a dead end. By the time you make all the compromises for water and waves, the gains for flying are lost. Low flying is not safe, even over water. Go fast enough and you may as well just climb to a safe altitude.
Kavin, what if you can make the hydrofoil appear and disappear? Kind of coming out of the side-floats. Reason: just make the floats lift a bit out of the water, just to reduce drag of the hull. Once it is a bit higher, flip the hydrofoil back in and ... lets hope the decreased drag (floats higher and hydrofoil gone) will let the speed build up for take off. No need to flip them out for landings.
Best example of book/internet knowledge and actual knowledge. Lots of people think they know stuff because they read about it, but real life have its own rules. People love to comment trying to correct someone or give suggestion when they never saw or try that in real life by them self.
You can reduce ventilation with a delta shaped foil protruding in front of the struts, less weed and a larger planning height range. i mean just the tip outside is enough for planning by ventilation ( just when you want). Short strut, small delta at an high AoA near the leading edge
I was kind of hopeful that the hydrofoil would help mitigate the turbulent water issue that GEV's have, but it sounds like it's a bigger engineering issue.
You probably could just use some high-quality brazing material to make that hydrofoil and keep the added material to a minimum, helping it stay aqua dynamic.
Also, make them WAAAY thinner. Like paper thin. It’s lifting up a piece of foam, not an anvil. I don’t think you need the airfoil shape either, just a knife edge both on the trailing and leading edge 🤷🏼♂️ Because it’s lifting such a small amount of weight, simple displacement should be enough to lift it up, airfoil generated lift is unnecessary and probably a source of drag.
I love, love, love the hydrofoil. Tweaking the placement is great. Since water is 800x denser than air, would it make sense to make the foil 800x smaller than the wing for a comparable lifting force?
What about the Sea Dart's water skis? They don't appear to use a foil design to gain lift out of the water. How efficient would skis be for amphibious aircraft?
@rctestflight : Maybe the submerged part could be used as an automatic pitch control if its design was different: I imagine a boom protruding 30 cm at the front, on the central axis, an a curved ski (like a comma) attached to the end. It could be a thin (5mm wide?) carbon strip, like the one we use to reinforce wings etc, which elasticity will provide the curved shape under the stress, and a dampening of the waves. Maybe you will have to overlay several strips like a leaf spring to have a more rigid front. Then tune the angle of the entry in water so it maintains the plane pitch close to the stall angle...
Always appreciate when you include information about aerodynamics; I didn't know about the foil shape stagnation point and you always do a great job simplifying it! Thanks for another great video sir!
Good work on finding the camera. I lost a GoPro 10 at 35' depth. Found it a day after I lost it with a fresh tank, There is not a good GoPro mount available to anchor one for static underwater video. I have been filling goosenecks with lead pearl weights. Works OK.
8:00 This is so fascinating. It's like how a truck has better fuel efficiency with the tailgate up even though you'd think that would produce drag, but it actually doesn't as it's designed to create a pocket of turbulent air that the other air just flows around. Driving with the tailgate down removes a tiny bit of theoretical drag from the tailgate, but adds more drag around it because it gets rid of that pocket.
Cool vid as always! I'd love to see another long-distance autonomous project, either boat, plane, or maybe revisit the rover? Those were really interesting, but I understand they take a lot of time to make
That Regent aircraft is definitely a seaplane they just designed it to be good in ground effect as an airplane is concerned, half the wing length above the surface is enough to “help” going only over water and not able to fly higher is probably for safety reasons. Seems hard to use practically but a very cool project nonetheless. Your videos are awesome I watch till the end keep ‘em comin!
In my youthful days like 50yrs ago I fashioned a model hydrofoil boat using steel tape measure fragments. It worked best in an identical front and rear dihedral configuration and surface planed very stably.. the hydrofoil thing applied optimally probably enhances the transition to ground effect more rapidly.. other than that mabe. You're clearly a dab hand with a tig.. 👍
@rctestflight SR-71 strakes are not for aero. They're for reducing radar cross-section for approaching missiles. At supersonic speeds flow separation is an even bigger concern. The faster you go the rounder you need to be. Look at the Space Shuttle, which enters atmosphere at approx Mach 21. Blunt. Otherwise it would be impossible to control. And it would melt because of the increased friction from the turbulence of a shallower boundary layer. That much you got right. To vary the lift with the depth, add more hydrofoils. As the upper ones leave the water, lift is lost. Add sweep so it has better odds of shedding weeds. Yeah that will be less lift, but it should also help it shed air, which is more consistent lift.
I would try to do it the other way around. Like a foiling boat that also uses groundeffect. With a propeller in the water and not in the air. just using Ground effekt for extra lift.
Another thing with cavitation bubbles is that they're extremely bad for whatever's causing them. if you look at propellers who cause these bubbles, the metal itself is being coroded away, which causes more spots for bubbles to form, which makes it a feedback loop.
So, hydrofoils get less efficient as they get closer to the surface, but airplane wings get more efficient the closer they are to the surface, and race cars produce more downforce the closer they are to the road… Fluid dynamics is weird
The reason that your "knife" T-foil oscillates in and out of the water is that it is too far forward. If it were behind the center of mass, increased lift by the foil would pitch the craft downward, reducing lift by the wings. This produces a mechanical negative feedback that stabilizes the height of the craft above the water. If the foil is placed ahead of the CoM as you have it, increased lift by the foil pitches the craft upward. This increases both lift and drag and causes the foil to leave the water. This also produces a "coarse" negative feedback as lift is reduced when the hydrofoil is out of the water. So the craft oscillates between the foil being in and out of the water.
@@rctestflight You'd need to mount the motor with an upward thrust vector, to counteract the negative pitching moment that the foil would create and bring the overall moment closer to zero. If you do that then the foil will exhibit mechanical negative feedback. It would be a funny looking craft, sure -- the motor "dragging" the foil along. But it would work and be monostable!
The fastest sail hydrofoil, the vestas sailrocket, specifically uses a sharp foil that cavitates due to how cavitation significantly reduces drag. It's an extremely unique design that only works in one part of the world, and the foil actually holds the boat down instead of lifting it while the sail propels and lifts the vessel. I'm of the opinion that the cavitation issue is basically the naval equivalent of the sound barrier, and the struggle to overcome its issues is not dissimilar to how difficult it was to design a plane that could break the sound barrier that could still fly regularly up to that point. I reckon that within our lifetimes someone will figure it out, and there will be a special classification of ultra fast foiling vessels. Probably military if we're all being honest.
Established Titles is on a marketing spending spree like you wouldn't believe. For the last two weeks or so I can't watch a YT video without them popping up.
You know its technically illegal to sell titles in the UK. I see this time and time again of companies using US TH-camrs to advertise this. There has been many instances of people "flaunting" or attempting to advertise their Lord or Lady title they have bought and being arrested. YOU GAIN NO UK HONOURS FROM THIS. The company that sell these small plots of land just has "permission" (which is dodgy as it is, as they could literally just make it up that you are buying a piece of land) from a land owner who has ACTUALLY been properly given the Lord or Lady title. In ANCIENT English law, if any land owned by any such title holder was sold to anyone else, than that person would also adopt the title themselves. However, this is not real today as no in those olden times, sold a singular sqft piece of land. It was a waste of time and land was precious. Lord or Lady titles may only be used when anointed by a member of the royal family, Duke(Duchess) or Baron(Baroness) in today's law. The ONLY way to gain any title properly in Scotland is to buy a Scottish Feudal Barony. They can start at $100k, with recent ones auctioning off for over $2m... Claiming a title such as Lord or Lady can be tried and prosecuted in court. This is known as "Cash for Honours" which you can look up if you wish.
Well at least you gave it a try. I can see why a foil could be useful for real scale ground effect planes. Like you said to save weight, and also to land safer at lower speeds before they enter a busy shipping lane or harbor, and still being able to reach the destination or a harbor at a reasonable speed. So basically it would be a substitute for a landing gear with wheels just to save weight on the hull and to protect the hull from the force of the water at a higher traveling speed once the plane stops using the ground effect. I think that it makes sense for real scale and real life conditions. But it would not make any sense at all to keep the foil in the water at all times, even when the plane is traveling at the speed when it uses the ground effect. That would be the same as if you fly an airplane low across the water while dragging an anker.
I feel like the point of ground effects is to carry a high amount of weight for a lower amount of thrust. Can you pile a bunch of "cargo" on the vehicle?
We played with something like this back in aircraft mechanic (A&P) school. Weight always seemed to stabilize or at least make the foils more usable. Of coarse, weight+plane=bad
I think there's one more way to pair these two forces together and that's the way the Vestas Sailrocket 2 achieved it. The two forces have to be in opposition. In the case of the Sailrocket, the hydrofoil actually pulls to keep the boat near the water rather than lift it. I think Sailing Tip's video on the topic explains it very well, I recommed checking it out.
The main difficulty in creating a hybrid vehicle, both a hydrofoil and a plane, is that a hydrofoil looses elevation when "lifting off" - cutting through water at near zero depth. The vehicle must not rely on its submerged flaps in order to gain take off elevation; on the contrary, it must rely on the elevation it wings. There must be a way to minimize drag of the flaps while taking off - perhapse folding them to a vertical position so at least they don't cause instability. Of course, there should be two flapse in this case, to balance the forces.
I imagine this adds a level of complexity that would go against some of the design principles, but could you have the submerged hydrofoil set up to retract? Something like an air speed sensor to determine when the ground effect would produce more lift efficiently compared to the hydrofoil so it can pull up and get flush against the wings. That or something like a speed limiter based on one of those metal rod force sensors that bend minutely to detect force. You could have throttle limited to the force on the foil. Having a foil per motor with immediate feedback from a sensor like that could produce a nice bit of stability.
I would suggest a different approach for the hydrofoil. Look at them as two wheels each side of the aircraft, with a builtin suspension. Make them as a V shape thin flexible blade, the more they sink the more lift you'll get. Add some independent damping system for each one. Make adjustable convergence to stabilize yaw. Keep good videos!
Back in the 70s the Air Force Research Lab put a hovercraft guts on the bottom of an airplane (a C-7 Caribou IIRC, called the Air Cushion Landing System or ACLS). Not sure what their results were, but it sounds like something you would try.
A true engineer with big field test experience. And not scared to fail, jump up again and integrate the learnings. A truely PDCA Dreamer 😂 I love your approach.
Come for the science and action stay for the awesome tunes at the end
Reminded me of the Jeffrey Bezos song by Bo Burnham.
th-cam.com/video/pI6iF6uQHcw/w-d-xo.html
🤣same🤣
@@runklestiltskin_2407 that's the song they based the one at the end of the video on lmao
Always
Hydrofoil, ***k yeah!
Truly impressed by Daniel's ability to find every lost or crashed plane, wing, drone or camera.
Established titles is a scam and the Ekranoplan did it first
criminal investigators should take note
He's like a airplane blood hound
"Established Titles"
1. No land ownership
2. No legal name change
3. No proof trees planted in Scotland 4. Pricing indicates product is real
D)
5. Upon checkout, buyer is automatically
subscribed to a monthly fee
6. On website, they talk about no land taxes
in Scotland, inferring you own the land
7. Company owns two other brands linked to scams
8. Company lists an office in Scotland but no
office exists, they are in Hong Kong 9. Company personally attacks critics
10. Ads use words "legally", "officially" and "formal", none are true
11. Website verbiage changed after being accused
What else does anyone need in order to realize this company is predatory and highly unethical?
Truly unimpressed Daniel is promoting a scam.
I always enjoy your little side quests, like finding a submerged camera :)
The Line through the Clouds is called a Distrail - or dissipation trail, the opposite of a Contrail - or Condensation trail. Both have the same cause - heat and condensation nuclei from the engine exhaust creates localized areas where the water vapor is condensed into tiny ice crystals or water droplets. In the Distrail- the effect creates larger droplets from already condensed mist (the cloud) which are large enough to fall away, leaving an open lane in the cloud.
No, it happens when the plane is sucking up water to mix with its stores of dry chemicals, so it can continue in its mission to leave chemtrails. You know, to poison us or drug us into submission or whatever it is the nutters say they're doing.
They just didn't have their Chemtrails pumps going !
Good to know....
The distrail was caused by an earlier plane in a different path, not the one at 21:34
no it's not, it's from the chemicals they dispose of in jet engine fuel, read about chemtrails
the level of details and depth in those projects is always stunning.
"Depth"? I dunno man it looked pretty shallow to me... 6:40
@@Daruma_Studio from a little beam shaped object, that must be like the Matianne Trench tho...
My 5 cents about sharp foils: recently I dove into hydrofoils thing too, designing impeller blades for waterjets. And when I was about to use some basic airfoil I suddenly found the airfoils for water are actually different (surprise) from airfoils for the air. The main reason is the cavitation. And the other reason - much higher water resistance: many hydrofoils do use sharp leading edge. Anyway - within working range of allowed angles of attack (usually something from -13 to +13 deg.) the sharp leading edge works ok.
Was about to say that, due to the viscosity of water, a sharp leading edge is better. Look at boat/yacht shapes the sharp edge is at the front, contrary to airplanes where the sharp edge is at the back.
@@pawelrelidzynski680the sharp bow angle on boat hulls is meant to reduce the bow wave created at the interface between the air and water. Torpedos and submarines use rounded fronts because they are fully submerged
@BlueIron64 i get your point, but that is not entirely true. You can see some bigger ship types being rounded in front and thats due to the speeds they travel. In water there is less resistance with a pointy shape in front, and i have seen it in a controlled environment. Same with air, less resistance when the frontsurgace is rounded and pointy in the back
"Established Titles"
1. No land ownership
2. No legal name change
3. No proof trees planted in Scotland 4. Pricing indicates product is real
D)
5. Upon checkout, buyer is automatically
subscribed to a monthly fee
6. On website, they talk about no land taxes
in Scotland, inferring you own the land
7. Company owns two other brands linked to scams
8. Company lists an office in Scotland but no
office exists, they are in Hong Kong 9. Company personally attacks critics
10. Ads use words "legally", "officially" and "formal", none are true
11. Website verbiage changed after being accused
What else does anyone need in order to realize this company is predatory and highly unethical?
daaaaaaaaaaaaaaaayum thats wild, thanks for the info
It’s because people don’t actually look into their sponsors. I’m surprised it took so long for someone to look into it and find what’s wrong with it. Although we will give this guy a little slack since the expose was about a month after this video was made.
Wow thats realy bad xD but the realy bad thing is that this youtuber promotes them LOL 😮
@@fluppet2350 slack or no slack, it indicates he didnt look into his sponsors. I came across this company years ago and thought it seemed cool, but after a 20 minute google search it was clear they werent legitimate. Whatever "expose" happened recently wasnt necessary to see through their ruse
"so that's why we can't have sharp hydrofoils"
I think what you meant to say was:"so that's why we need to make this thing supersonic" 👍🏻
a little suggestion for the drone that went in the water: spraypaint the waterbottle a bright color so its very easy to spot when upsidedown in the water like that
or fill it w/ expanding foam, so incase it is damaged it does not sink whilst also being more visible
Good suggestion. As color I would recommand a bright orange or red.
If something samller would be wanted maybe the mechanism of an automatic life vest could be copied.
Also, a small LED light inside the bottle would be a good idea. It doesn’t add much weight but will provide you several hours of super accurate positioning.
@@arlenn729 yeah. That would be kinda sick
The transition from hydrofoil lift to flight on the Regent aircraft seems to depend on a pitch-up "launch" to get more lift by increasing the angle of attack. While this might work, passengers might find such a maneuver more than a little unsettling.
its useless
I noticed that. It looks pretty jarring unless they have some special seat suspension that can enter the cargo area.
@@XenoWiz more motors does increase the safety in case of a failure
@@XenoWiz more motors actually generate more power than a single big motor due to tip speed limits. If your tips start hitting the sound barrier they won't generate as much thrust and will generate a ton of drag. As such you can run a smaller motor at much higher speeds and have more of the blade in the "optimal thrust region" For electric motors having a bunch of smaller motors has major benefits, the first being that you don't need to put huge amounts of current through a single wire (fire hazard). The second is for motor cooling, third is cost (a bunch of small motors is cheaper than a single big motor). The Blown Wing isn't a new technology, it's been used for decades on drones and has a long history with STOL. It actually does work since the effect of the wing is independent of the ground this allows for a functionally higher airspeed over the wing than your actual groundspeed, it's like taking off into a headwind. Momentum is conserved since the lift and thrust are (mostly) perpendicular to each other.
The reason why airplanes traditionally favoured having one or two big engines is because that was also their main powerplant. ICEs are big and heavy, their power to weight ratio is actually very low compared to electric motors (batteries and fuel not included). Gas turbines have a thrust to weight ratio comparable to electric motors. So why aren't electric motors used in aviation as much? Well batteries are heavy, much heavier that fuel, and that tends to be the deciding factor. And jets generate just so much power so easily that it's kind of dumb not to use them despite their complexity.
Yeah, you dweebs are just noticing a particular movement of a test vehicle and trying to extrapolate it into an inescapable aspect of the final product’s operation. Nice try dorks.
The reason why the flying boat has hydrofoils is exactly to *prevent* what you geniuses think it will cause; jarring vibration/shock.
A normal flying boat rides on the surface of the water, planing before it rotates. That means that the roughness felt by the passengers is directly related to the roughness of the water’s surface. If a seaplane has hydrofoils, it can quickly lift off *above* surface irregularities, causing a smooth ride as it builds enough speed to rotate. The only time you’d feel the rough surface/waves is at initial acceleration stages when the speed is low and affect on the airframe minimal. Basically a little rough right at the beginning, then transitioning to an incredibly smooth hydroplane affect, followed by a rotation that I’m sure can be modified in it’s severity. They probably just made it look like it was “jumping” out of the water for a cool promo video.
Y’all really need to look at the big picture, how the entire machine operates, and not just autistically and pedantically notice one single aspect and think your assumptions are that of a smart person….
I've gotta say it's really nice to have someone to watch who just researches and tests things for the fun of it, it really keeps me motivated to just work on things that I think are interesting
In regard to what you mentioned on the jet. Why wouldn't skis be the ideal solution to most of these problems? At low speed the waves aren't an issue on the hull. At higher in water speeds the skis will plane, lifting the body/wings away from the waves. And then at highest speeds, when your airborne, then the skis could be retracted like landing gear against the body for a smooth hull. This seems to give you the best configuration for all three speeds for takeoff/landing transitions.
Skis would induce a lot of turbulence and drag but yeah if they were retractable it seems like a good idea. I just wonder if they would really help ekranoplans with the choppy water problem because they wouldn't be very useful at cruising speeds?
Video: this video is sponsored by established titles
Me: *run*
You're so knowledgeable about flying and boating that it makes the episodes fascinating to watch. I like when in some episodes you get super excited. It feels infectious! 👍🏻
I've learned so much from these videos but... I'm not going to lie, watching you recover shit you've lost is one of my greatest joys.
Hi! I was so happy to see my mug in the "instigators' list" 😊
Thank you so much for making all the research and the tests. As you suggest in the discussion, hydrofoils would need to be short and possibly retractable (although they provide a tiny amount of lift in the air too, with some added instability). The goal is to leave the water as soon as possible to make the transition to and from airborne as fast as possible, especially in choppy waters -- the goal is to fly over the sea, which is *never* flat, even in a cove.
From what you show and the Regent experment (I wasn't aware of this one), you'd use T-foils as they seem to provide more lift and less drag at low speed, and more than just one at the front spread around the CoG (i.e 1 ahead and 2 on the sides behind, or 2 and 2, adding to the same surface).
Currently, I'm more on the Lippisch design (inverted delta) with 12º anhedral to which I add canards, the idea being to add 1 hydrofoil under the fuselage and 1 under each of the floats located at the ends of the wings, so to transition as quickly as possible to airborne. So far, the canards are attached to a nacelle at the front (like big ears on the head of a flying duck) because I wanted to have wings swept 30º forward (making an skirt open 120º in front), but I probably drop that to no-sweep and have the canards attached to a straight edge so to modify the entire wing geometry by moving the canards'edges up and down.
Thank you again for all the work and the actual experimental results you provide. Keep up the fantastic job!
This is the video I've been waiting for for ages! Your closing remarks are the most valuable to me:
1) Hydrofoils could help get GEVs and seaplanes out of the water, and perhaps aid in landing.
2) They'd have to be retracted to make efficient use of GE.
3) This bonus is not present at RC scales (likely due to smaller mass to surface ratios and lower Reynold's number).
This had indeed been my hunch, but I'm so grateful to you for actually doing these tests and giving your expert's opinion. My motivation for the idea has always been the tell-tale fact that the Ekranoplan allegedly used 8 turbines to take off but only 2 for sustained flight. Perhaps one could also improve efficiency at sub-takeoff speeds by propelling the craft against the water rather than the air - e.g. by a mounting a boat prop to the back of the hydrofoil, or by creating a water jet with water sucked in through a hollow foil.
Jet powered take off ekranoplan sounds extremely badass
@@wiegraf9009the giant ekranoplan did that and then fly the entire thing with only 2 turbojets
Just to save you some money in the future: the steel you buy usually isn't hardened, so high carbon steel isn't harder than regular steel (mild or construction steel) unless you actually temper and aneal it. Not that it matters a lot in those quantities, but tool steel is about twice as expensive as mild steel :)
Additionally, brazing might be a better (easier) way to to attach pieces like that without sacrificing much strength.
Anyway, awesome and educational video as always!
PSA: Be cautious about what craftsmen/tradesmen tell you about heat treatment. Many of them are notorious for getting it wrong because they tend to learn by word of mouth and trial&error rather than reading about material science. And we all know how the game of telephone tends to go.
Heat treatment is a science. A branch of material science, to be exact. And it's complex enough to require highly educated and dedicated specialists when doing R&D for big expensive projects.
Anyway, annealing undoes tempering, and tempering improves strength, not hardness. Quenching fast makes it hard, though also much more brittle. Tempering reduces brittleness whilst retaining higher hardness than other processes, which ultimately increases its' overall strength. Coincidentally, that metric is called 'ultimate strength', which is different a completely different metric from 'hardness'. Look up the tests for measuring those two.
Annealing is the process which kind of 'resets' steel, typically used to maximize machinability (make it softer/more easily workable) and remove internal stresses due to forging and machining processes. It's also typically quenched more gently so you aren't left with an overly-brittle product.
Really great video as always, Daniel!! Thanks for including us in your projects 👍🏼Glad I got to hear your friends’ sweet tunes also! 🤘🏼
Outstanding! Thanks for teaching me about ventilation. Never heard of it before though I've seen it before while not recognizing it as anything. Amazing footage between the drone and the ground effect "napkin"!
Just a gut feeling - when there is no physical connection between an air cushion vehicle and the water, there must be
less drag than if you dangle some shape, any shape down into the water. Your interesting experiments proved just that. The air cushion principle is so elegant in its simplicity. One hypothesis I'd love to see you try is fencing - i.e., Run a raked vertical fin down into the wateron the rear inner faces of your sponsons. Seems to me that you could extend the cushion of high pressure air further back, negating form drag from any horizontal surface touching the water.
My theory is that fins would yield two benefits - first, lower form drag, and second, better lateral stablility.
I'd love to see you throw some fins on your mature research aircraft!
you should look into supercavitating hydrofoils. I reckon you'd love em! Im currently developing one for a high-speed foiling windsurfer down here in the choppy waters of the Swan River
16:20 looking at it, I'd say that it's almost certainly possible to land it without stalling at 52kts-- taking off would be more difficult, but the ground effect should help it reach the speeds it needs (for example, in soft field takeoffs, we lift off much sooner by applying full back elevator pressure-- however, once in the air, we immediately let off pressure, and stay in the ground effect until rotate speed). I'm pretty sure that plane's wingspan is long enough that it can be in ground effect without the hydrofoils being in water, so I imagine that's how they'll do it.
11:55 "that's the cutest little tugboat i've ever seen"
3D benchy in real life
if you have a multiple stage hydrofoil: the bottom one, smaller, pulling down, and a bigger that would skim the surface, perhaps with a mechanical 'feeler' that would auto-adjust the height?
Great video! I'm curious, have you tried a "fan wing" design before? It would be cool to see if you could combine the ground effects stuff with the supposed "ultra-high efficiency" and short take off distance that the design proposes. They're not capable of high speeds nor high maneuverability, but I'd like to see how efficient they can get.
The reason why the flying boat (Regent) has hydrofoils is to prevent jarring vibration/shock;
A normal flying boat rides on the surface of the water, planing before it rotates. That means that the roughness felt by the passengers/airframe is directly related to the roughness of the water’s surface.
If a seaplane has hydrofoils, it can quickly lift off above surface irregularities, causing a smooth ride as it builds enough speed to rotate. The only time you’d feel the rough surface/waves is at initial acceleration stages when the speed is low and affect on the airframe minimal. Basically a little rough right at the beginning, then transitioning to an incredibly smooth hydroplane affect, followed by rotation.
It actually makes a lot of sense. Same thing with landing; land on the hydrofoils, then by the time the plane decelerates enough they don’t generate enough lift to lift the airframe above the water, the plane is going slow enough that the rough water won’t be too abusive to the airframe.
Good video, the ventilation demo was cool. Established Titles is a scam though and you should check sponsors better before accepting them
There are hydrofoils that use supercavitation. This is just forced cavitation at higher speeds and can increase both top speed and efficiency. I think the largest benefit to adding both ground effect and hydrofoils into one vehicle would be it’s very high weight capacity; high weight would also help with the foil staying close or in the water… last thing, foils can also be used to pull the craft towards the water preventing the bouncing created with ground effect.
Daniel, I am always amazed at how much science and education you pack in your videos, but ngl my favorite part is always the music videos at the end. So lucky to have your own personal musician! :D
Hello, I am an embedded systems and aeronautics engineering student and I think you can keep the hydrofoil in the water by increasing its surface by making it longer but also larger. u could also place the rotors behind the aircraft (like the sr71 for example) and move the hydrofoil more towoards the nose/front of the aircraft. so the thrust is coming from behind and its helps stabilisation, or even better ur can do the opposit keep the rotors in front and bring the hydrofoil more the back you should try it actually it could be interessting keep in mind that performing these two ideas might introduce the need to add a variable angle hydrofoil for way better stabilisation !
Mr Daniel, I'm glad to see you again in my top video suggestions, its been a while. :) Hey, also, thanks for your previous videos on the auto gliders and solar planes etc... I'm almost done building up my ASW 28 for the auto soaring via ArduPilot, same as you did. Keeping on doing your thing, its top tier!
That ventilation demo just before 10 minutes was really cool so thank you for doing that.
FYI established titles is a scam you’re better off just giving directly to something like one tree planted
You don't want a super low wing if there's any chance of chop. I live on the SF Bay and I want something to scamper from SF to the houseboat and back again. It's only about 5 nautical miles and sometimes the bay is calm, sometimes it isn't. Lots of hydrofoil options but ground effect seems to be a better overall choice - higher speeds, lower drag, likely better efficiency. I'm checking this out as it seems to solve the transport problem. Ground effect plus hovercraft means I can land on the beach or in the harbor. I'm also a Tesla Sr engineer and would want to EV convert it as a single Tesla motor is about 220kw, way more than needed for this application.
"What has he built _now?"_ -- The birds of Washington state
Just the fact that you was able to find that camera deserves a subscription
I love the evolution of these ground effect vehicles…
I think there might be a way past this with the full-size. Why does it cavitate? It cavitates because you're changing the direction of the water with the foil in order to achieve lift. If you were able to adjust the angle of attack dynamically, you could adjust it to zero, which would minimize cavitation and drag and eliminate lift at high speeds, or adjust it to steep, which would allow for high lift at low speeds.
Now we just need a helicopter that runs on ground effect
Wouldn't that just be a -leg- _hedge-trimmer_ or something? XD
Isn't that a hovercraft?
Wonder if having a different wing profile would be better for hydrofoils, maybe even capturing the ventilation/cavitation air bubble and using it for lift. I know there are some boats with flooding compartments (flooded when not moving, for stability. Empty out as the boat starts to move for higher speeds.) Applying this concept to a hydro wing make me think of basically one with a front slat, but the slat is attached at the bottom. Or just a channel slightly behind the top of the wing profile. My thinking is that at speed this would create a pocket that would either just help with lift, air is lighter than water an all that, or serve as a vent to bring the gasses along the foil and out of the water, away from the wing itself.
Please dump sponsors like Established Titles (others that come to mind are Kamikoto or RAID Shadow Legends). They're effectively scamming people out of their money. Sure, it's only a novelty gift, but charging 50+ dollars for absolutely nothing (maybe a single planted tree) is still a scam.
Kamikoto is actually part of the same parent company, although they sell actual products under false pretenses (shitty mass products that they claim are handmade quality products).
Actually, the stagnation point does not remain static with changes in angle of attack. As the angle of attack increases the stagnation point moves backward from the leading edge, on the lower surface of the wing. At high AOA a small portion of airflow on the lower surface is inverted, spilling forward and up from the high pressure under the wing to the low pressure above it, and you can easily test this with smoke tests in a wind tunnel or with short tufts attached to the leading edge of the wing.
I need to go to sleep, you can’t upload now
haha I already slept
Ha I just woke up
Literally 😭🤣
Feel that one
Its daytime dummy
Someone may have mentioned this but there are hydroplanes that use cavation to produce lift. They have sharp leading edge with square traling. The fastest sail boat uses one.
Found mysel
. . Myself wondering how cavitation fit into the equation with hydrofoils.
Established titles is a scam
Why
Why
Why
Why
@@obvossy4433you don’t actually get anything. You arent a lord or anything and you arent buying land or whatever
I learnt from one of your videos that I can replace the battery on a Dyson vacuum. This saved me from buying a new one. Thanks mate!
Established titles is a scam , please stop pushing this scam
I always thought about building one of those, except my concept was sort of a airplane with legs where the lifting body (passengers and pilot) is in front and the waterski/foil part (power source) remained attached to a surface on a sled.
About the Regent Seaglider - their prototype also has wingtip pontoons whose holders (not sure of the technical term) prevent the air from escaping sideways and thus increase efficiency. For added bonus, I suppose they act like winglets and help in airplane mode as well. Not sure why they don't have them in the final design. Plus, as mentioned - high wingspan helps keep efficiency even if the wing absolute height is... well higher. Which, in turn, helps operate in rougher weather.
Reverse delta ground effect vehicles can also get away with higher wings (at least their leading edge). Also not sure why we don't get more of these.
Based on my experience in sailing hull design, I wondered if making a V hydrofoil would help with the transition from air to water. A more gradual "entry".
I also was listening to an AC foiler Catamaran discussion, where they noted that any vertical surface entering the water, induced air down to the foiling surfaces, and created cavitation.
That diagram showed foils entering the water with Dihedral angles, :1:57 - "Surface Piercing" instead of straight down. "Fully Submerged"
Those two category's at :1:57 are deceptive. ALL foils are Surface Piercing, unless you are a Submarine.
That camera searching cut scene was epic
Drone down 18:41, 18:46
Camera drown 7:02
Hydrofoil frown 13:01
Daniel not messing around,
for he's no clown.
Why I love this channel: *says something super technical I barely understand* and then “woah that cool boat has a crane”
This is the first RC controlled sushi producer!
Just a thought on turning a ground effect vehicle. Since your essentially flying flat, your tail section should steer like a car linkage. And, the front wing on the inside of the corner should create a small amount of non lift creating drag. Kind of like breaking one wheel on a car to make a tighter turn, but just slightly. Anyway, that was a fantastic lesson.
Fascinating video. Essentially the lack of water pressure differential in the couple of inches the foil pierces the water for a model robs the model of the lift increase provided by the feet a full-sized foil pierces the water.
The main advantage of the hydrofoil is the ability to maintain a higher speed in moderate sea conditions without pounding the passengers into jelly, as would happen for a planing hull. For a model, ground effect just seems better, as long as you get enough altitude to avoid the waves. Which is why experimenting with multiple foils is probably just a waste of time.
Excellent video as always!
With regards to the use of hydrofoils, Regent are selling their addition as a different phase they can operate in. Ie they can operate in an area close to shore on the foils at relatively high speeds without the wake. When they then get out in the open they can proceed to flying. Rather than solely a way to get the craft out of the water more efficiently.
The thing to be concerned about with foils is the possibility of ''hooking' them in the water at high speed as happened with the X114. The Seaglider retracts them to avoid this. But there is still the concern about the conflicting aerodynamic/hydrodynamic forces/moments between foil and wing lift. They are very hard to marry up.
Great take on an interesting area of developemnet , The Americans spent a lot of time on foils on seaplanes ,in the 1940s ,not a lot came of it ,I now see why maybe . An Aussie guy has gone water ski waywith his boats, 'sea ski', may be the best solution for a lighter 'water form' for amphibian and sea planes . Of course modern materials can make lighter stronger hulls too .
Hey I'm in a video, cool! Thanks for the mention. Excellent exploration of the concept! It's cool to see the historical applications of the tech, so thanks for including those. Ventilation is the WORST when winging, I think that's the appeal of high dihedral front foils, although you rarely see it in rear stabilizers. I'm sure you've done plenty of research while making this thing, but if you want to get into hydrofoiling, there's plenty of money in the industry now, particularly wingfoiling, since it's the new hot thing, so lots of watersports companies have been investing in research to create the best hydrofoils. It's neat to see the differences in performance, high/low aspect, lots/no dihedral, thick/thin wings. I was toying with the idea of creating a biplane style hydrofoil, where the lower wing is smaller, creating less lift, but less drag to provide a gradual transition to flight, but you've proven pretty well the combination with ground effect aircraft isn't super compatible. Well done, keep playing!
Have you considered trying a water rudder with one or two vertical fins to provide horizontal force? You never seemed to be able to turn too sharply while in ground effect, that could give you some much sharper maneuverability.
Excellent stuff!
I reckon skis with suspension are a better match to GE. No finicky stability issues, no ventilation or cavitation, no weed or flotsam issues.
I'm pretty sure now GE is a bit of a dead end. By the time you make all the compromises for water and waves, the gains for flying are lost. Low flying is not safe, even over water. Go fast enough and you may as well just climb to a safe altitude.
Kavin, what if you can make the hydrofoil appear and disappear? Kind of coming out of the side-floats. Reason: just make the floats lift a bit out of the water, just to reduce drag of the hull. Once it is a bit higher, flip the hydrofoil back in and ... lets hope the decreased drag (floats higher and hydrofoil gone) will let the speed build up for take off. No need to flip them out for landings.
Best example of book/internet knowledge and actual knowledge. Lots of people think they know stuff because they read about it, but real life have its own rules. People love to comment trying to correct someone or give suggestion when they never saw or try that in real life by them self.
The Foil has to be on the back of the plane like a wingfoiling board
You can reduce ventilation with a delta shaped foil protruding in front of the struts, less weed and a larger planning height range. i mean just the tip outside is enough for planning by ventilation ( just when you want).
Short strut, small delta at an high AoA near the leading edge
I was kind of hopeful that the hydrofoil would help mitigate the turbulent water issue that GEV's have, but it sounds like it's a bigger engineering issue.
You probably could just use some high-quality brazing material to make that hydrofoil and keep the added material to a minimum, helping it stay
aqua dynamic.
Also, make them WAAAY thinner. Like paper thin. It’s lifting up a piece of foam, not an anvil. I don’t think you need the airfoil shape either, just a knife edge both on the trailing and leading edge 🤷🏼♂️ Because it’s lifting such a small amount of weight, simple displacement should be enough to lift it up, airfoil generated lift is unnecessary and probably a source of drag.
I love, love, love the hydrofoil. Tweaking the placement is great. Since water is 800x denser than air, would it make sense to make the foil 800x smaller than the wing for a comparable lifting force?
What about the Sea Dart's water skis? They don't appear to use a foil design to gain lift out of the water. How efficient would skis be for amphibious aircraft?
@rctestflight : Maybe the submerged part could be used as an automatic pitch control if its design was different: I imagine a boom protruding 30 cm at the front, on the central axis, an a curved ski (like a comma) attached to the end. It could be a thin (5mm wide?) carbon strip, like the one we use to reinforce wings etc, which elasticity will provide the curved shape under the stress, and a dampening of the waves. Maybe you will have to overlay several strips like a leaf spring to have a more rigid front. Then tune the angle of the entry in water so it maintains the plane pitch close to the stall angle...
Always appreciate when you include information about aerodynamics; I didn't know about the foil shape stagnation point and you always do a great job simplifying it! Thanks for another great video sir!
I love how the insta go is white, perfect for dropping it in the snow!
Good work on finding the camera. I lost a GoPro 10 at 35' depth. Found it a day after I lost it with a fresh tank, There is not a good GoPro mount available to anchor one for static underwater video. I have been filling goosenecks with lead pearl weights. Works OK.
8:00 This is so fascinating. It's like how a truck has better fuel efficiency with the tailgate up even though you'd think that would produce drag, but it actually doesn't as it's designed to create a pocket of turbulent air that the other air just flows around. Driving with the tailgate down removes a tiny bit of theoretical drag from the tailgate, but adds more drag around it because it gets rid of that pocket.
You should do some testing with propulsion mounted in the hydrofoils. Propellers are much more efficient in water.
Cool vid as always! I'd love to see another long-distance autonomous project, either boat, plane, or maybe revisit the rover? Those were really interesting, but I understand they take a lot of time to make
That Regent aircraft is definitely a seaplane they just designed it to be good in ground effect as an airplane is concerned, half the wing length above the surface is enough to “help” going only over water and not able to fly higher is probably for safety reasons. Seems hard to use practically but a very cool project nonetheless. Your videos are awesome I watch till the end keep ‘em comin!
In my youthful days like 50yrs ago I fashioned a model hydrofoil boat using steel tape measure fragments. It worked best in an identical front and rear dihedral configuration and surface planed very stably.. the hydrofoil thing applied optimally probably enhances the transition to ground effect more rapidly.. other than that mabe. You're clearly a dab hand with a tig.. 👍
@rctestflight SR-71 strakes are not for aero. They're for reducing radar cross-section for approaching missiles. At supersonic speeds flow separation is an even bigger concern. The faster you go the rounder you need to be. Look at the Space Shuttle, which enters atmosphere at approx Mach 21. Blunt. Otherwise it would be impossible to control. And it would melt because of the increased friction from the turbulence of a shallower boundary layer. That much you got right. To vary the lift with the depth, add more hydrofoils. As the upper ones leave the water, lift is lost. Add sweep so it has better odds of shedding weeds. Yeah that will be less lift, but it should also help it shed air, which is more consistent lift.
Wait but I never said the SR-71 strakes are for aero
Ok. Thanks for hashing this idea out. Next idea; can a ground effect flying surfboard be fun?
I would try to do it the other way around. Like a foiling boat that also uses groundeffect. With a propeller in the water and not in the air. just using Ground effekt for extra lift.
Another thing with cavitation bubbles is that they're extremely bad for whatever's causing them.
if you look at propellers who cause these bubbles, the metal itself is being coroded away, which causes more spots for bubbles to form, which makes it a feedback loop.
So, hydrofoils get less efficient as they get closer to the surface, but airplane wings get more efficient the closer they are to the surface, and race cars produce more downforce the closer they are to the road…
Fluid dynamics is weird
The reason that your "knife" T-foil oscillates in and out of the water is that it is too far forward. If it were behind the center of mass, increased lift by the foil would pitch the craft downward, reducing lift by the wings. This produces a mechanical negative feedback that stabilizes the height of the craft above the water. If the foil is placed ahead of the CoM as you have it, increased lift by the foil pitches the craft upward. This increases both lift and drag and causes the foil to leave the water. This also produces a "coarse" negative feedback as lift is reduced when the hydrofoil is out of the water. So the craft oscillates between the foil being in and out of the water.
Putting the foil behind the center of mass just makes it nose dive
@@rctestflight You'd need to mount the motor with an upward thrust vector, to counteract the negative pitching moment that the foil would create and bring the overall moment closer to zero. If you do that then the foil will exhibit mechanical negative feedback. It would be a funny looking craft, sure -- the motor "dragging" the foil along. But it would work and be monostable!
Very good lesson on the efficiency of hydrofoil
The fastest sail hydrofoil, the vestas sailrocket, specifically uses a sharp foil that cavitates due to how cavitation significantly reduces drag. It's an extremely unique design that only works in one part of the world, and the foil actually holds the boat down instead of lifting it while the sail propels and lifts the vessel. I'm of the opinion that the cavitation issue is basically the naval equivalent of the sound barrier, and the struggle to overcome its issues is not dissimilar to how difficult it was to design a plane that could break the sound barrier that could still fly regularly up to that point. I reckon that within our lifetimes someone will figure it out, and there will be a special classification of ultra fast foiling vessels. Probably military if we're all being honest.
I wonder if a swept or serrated hydrofoil would help with the ventilation issue
Loved the bo cover at the end too. Thanks!
Established Titles is on a marketing spending spree like you wouldn't believe. For the last two weeks or so I can't watch a YT video without them popping up.
You know its technically illegal to sell titles in the UK. I see this time and time again of companies using US TH-camrs to advertise this. There has been many instances of people "flaunting" or attempting to advertise their Lord or Lady title they have bought and being arrested. YOU GAIN NO UK HONOURS FROM THIS.
The company that sell these small plots of land just has "permission" (which is dodgy as it is, as they could literally just make it up that you are buying a piece of land) from a land owner who has ACTUALLY been properly given the Lord or Lady title. In ANCIENT English law, if any land owned by any such title holder was sold to anyone else, than that person would also adopt the title themselves. However, this is not real today as no in those olden times, sold a singular sqft piece of land. It was a waste of time and land was precious. Lord or Lady titles may only be used when anointed by a member of the royal family, Duke(Duchess) or Baron(Baroness) in today's law.
The ONLY way to gain any title properly in Scotland is to buy a Scottish Feudal Barony. They can start at $100k, with recent ones auctioning off for over $2m... Claiming a title such as Lord or Lady can be tried and prosecuted in court. This is known as "Cash for Honours" which you can look up if you wish.
@@Blackburn6969 I didn't know it was illegal, I'd figure out it's pretty much fake. Like buying a square meter of moon surface.
Well at least you gave it a try. I can see why a foil could be useful for real scale ground effect planes. Like you said to save weight, and also to land safer at lower speeds before they enter a busy shipping lane or harbor, and still being able to reach the destination or a harbor at a reasonable speed. So basically it would be a substitute for a landing gear with wheels just to save weight on the hull and to protect the hull from the force of the water at a higher traveling speed once the plane stops using the ground effect. I think that it makes sense for real scale and real life conditions. But it would not make any sense at all to keep the foil in the water at all times, even when the plane is traveling at the speed when it uses the ground effect. That would be the same as if you fly an airplane low across the water while dragging an anker.
I feel like the point of ground effects is to carry a high amount of weight for a lower amount of thrust. Can you pile a bunch of "cargo" on the vehicle?
If the fully Submerged hydofoil is shaped as a triangle (like a airplane Wing) the weeds can't get stuck on it. You could try this next time.
We played with something like this back in aircraft mechanic (A&P) school. Weight always seemed to stabilize or at least make the foils more usable. Of coarse, weight+plane=bad
I think there's one more way to pair these two forces together and that's the way the Vestas Sailrocket 2 achieved it. The two forces have to be in opposition. In the case of the Sailrocket, the hydrofoil actually pulls to keep the boat near the water rather than lift it. I think Sailing Tip's video on the topic explains it very well, I recommed checking it out.
The main difficulty in creating a hybrid vehicle, both a hydrofoil and a plane, is that a hydrofoil looses elevation when "lifting off" - cutting through water at near zero depth. The vehicle must not rely on its submerged flaps in order to gain take off elevation; on the contrary, it must rely on the elevation it wings. There must be a way to minimize drag of the flaps while taking off - perhapse folding them to a vertical position so at least they don't cause instability. Of course, there should be two flapse in this case, to balance the forces.
I imagine this adds a level of complexity that would go against some of the design principles, but could you have the submerged hydrofoil set up to retract? Something like an air speed sensor to determine when the ground effect would produce more lift efficiently compared to the hydrofoil so it can pull up and get flush against the wings.
That or something like a speed limiter based on one of those metal rod force sensors that bend minutely to detect force. You could have throttle limited to the force on the foil. Having a foil per motor with immediate feedback from a sensor like that could produce a nice bit of stability.
8:27, if sharp leading edges are bad at subsonic speeds, you'll only need to make a supersonic GEV with a hydrofoil.
I would suggest a different approach for the hydrofoil. Look at them as two wheels each side of the aircraft, with a builtin suspension. Make them as a V shape thin flexible blade, the more they sink the more lift you'll get. Add some independent damping system for each one. Make adjustable convergence to stabilize yaw. Keep good videos!
Back in the 70s the Air Force Research Lab put a hovercraft guts on the bottom of an airplane (a C-7 Caribou IIRC, called the Air Cushion Landing System or ACLS). Not sure what their results were, but it sounds like something you would try.
A true engineer with big field test experience. And not scared to fail, jump up again and integrate the learnings. A truely PDCA Dreamer 😂 I love your approach.