I 3D Printed The WORLD FIRST PROPELLER And Build an RC Boat With It

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In this video, I experimented whit historical ship propellers. Back in the day, the propellers were not like we know them today, they were screw propellers. How they performed on RC boats?
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[@christophermcdonald5578]

You should put the screw propellers in a tube and see if you get more thrust

[@RegisMichelLeclerc]

That's called a "duct", and that can be fairly more complicated that just a "tube", but you can expect all the force driven to the same direction without loss on the sides, especially when the movement of fluid generated by each "fan" of the screw is blocked by the following one, you probably want a camber at the "mouth" of your duct and a output smaller than the input.

[@DavidIvan-MC]

That’s a good idea

[@teslastellar]

Yes a duct will help a lot I think

[@SmoochyRoo]

Basically what a jet ski already uses

[@eduardofernandez5217]

A tube does nothin on such long screw

[@davel759]

I've been working on my own BLDC motor controller for a while now, and it's astonishing the ESC worked with two motors attached. The way they work is by listening for the back EMF from the phase that is not energized to know where the position of the motor is in order to advance to the next phase. If you have two motors, you also have two back EMF signals mixed together. It probably works because the motors are the same size, therefore they can get into lock-step with each other. It's really fascinating! If you would have asked me before seeing this video if you could drive two motors from the same ESC I would have said no way!

[@greggv8]

That's probably why it kept wanting to heel over. One or the other motor wasn't synching up and running slower.

[@JinKee]

Screws going the length of the vessle seem like the ultimate land/water propulsion system if you have an insane power to weight ratio

[@Sekir80]

You mean furze's screw tank? :D

[@blockstacker5614]

its been done

[@Platypus_Warrior]

Screw that.

[@simonschneider5913]

@@blockstacker5614 theres that russian vehicle, ZIL-2906.....crazy contraption - but quite effective! :)

[@crystaldragon141]

It does seem like an awesome idea but the biggest problem is friction.

[@RegisMichelLeclerc]

Your boat is undriveable because your steering is right in the wake of your 2 screws in very turbulent water, especially at high speed. If it capsizes when you go full throttle, it's not because of the speed, it's because of the acceleration and the torque. If you were accelerating more progressively, it would probably work better, although the water wall would always end up making the rear faster than the bow and make it capsize in a way or another anyways. One obvious solution for the steering is to have 2 rudders each side of your boat (even ouside of it) and drive them from your 9g servo with arms. When you drive your boat backwards, the rudder is before the turbulence of the screws so it has authority. You're then in the position of a trolley, with caster wheels at the front and push at the back, but it's not ideal because the camber of your rudder is reversed, the attack side of your hull if flat against the flow and thus is a huge brake... it's less bad, not better. However, it proves the point. Now, if you want to keep only 1 rudder at the back, you may think of putting your screws in a duct to to protect your rudder from the wake, and make your rudder a lot deeper. A common thing as well is to put a fin fixed to the hull before the rudder. Ducting your screw is simply going to put you in the situation of a "water jet", which is pretty powerful, probably too powerful for your styrofoam hull (too much torque). Also, one of the big advantages of a single-hull boat is to be able to lean on one side or the other to take advantage of the wind. To increase the amount of force you can take, you can use dedicated long fins (sometimes multiple ones) and/or a keel with a big weight. On a motor boat, unless you intend to surf, you want fins in front of your motors and probably a keel as deep as possible to enjoy the lever effect at the level of the floating line. It's usually unproductive to have mutiple keels because of geometry. Now, in RC world, you probably want to put floats on the sides to get roll+yaw stability. They don't have to be big, they just need to be as far as possible from the "main" hull, at some cost of maneuverability (spin). It doesn't mean screw propellers are wrong, well to the contrary, it just means you need to do things differently after observing what goes wrong depending on your actions. Put food colouring in your bath to make things easier to see, no need to have a degree in fluid dynamics to figure most things out. For the rest, you have thousands of years of solutions found by engineers at different eras in history... In terms of experimenting "unusual" methods, kinda related to the screw propeller, you may try to figure out what are those "caterpillar" propellers from "Hunt for Red October" (the book, the movie sucks). One of the reason you may want to go for screw propellers would be the noise/thrust ratio... and thus look for a solution that provides a little bit less thrust but with a lot less noise, or a solution that makes a lot more noise for a lot less power consumed for a similar level of thrust (I think of "propfans", here). Most problems already have solutions, just make your own blend, solve the interactions, don't rush to the goal: the enjoyable part is the path, not the destination.

[@GoldenCroc]

The "red october" propulsion system closely fits the description of a linear propulsion motor. There are some videos on youtube of people trying their homebrew versions out. Its not very efficient, but the "no moving parts" aspect of it is nice.

[@gottagift]

@@GoldenCroc leads me to wonder how to mimic the squids propulsion.

[@user-tf1oo9rj6u]

Tips: *(from a former naval architect)* 1. *Put the propellers on the opposite sides:* Currently, they throw thrust outward when trying to go forward. a lot of that pressure is wasted. Swapping the screw directions will push the water toward the center, making a more consistent centered thrust. Also, if you think about the screws applying torque to tip the boat, currently the low side wants to flip the boat! Once your high side screw got too high in the water, the lower screw quickly flipped the boat. Swapping the screws will make the low side try to correct/stabilize the boat instead. 2. With screws like that, you can *counter drive the thrust directions to intentionally crab-walk sideways.* (conceptually, imagine the screws are wheels. Since they normally spin opposite directions, if you spin them the same direction, they cancel forward/rev thrust, but "roll" sideways.) (if your controls will allow you to do that) 3. *use a balanced rudder:* whether you use a wing/foil shape or a simple flat sheet as a rudder, a balanced rudder will perform much better and significantly reduce the torque on your motor. What is meant by "a balanced rudder" is this: look down from the top. You have a centerline/pivot. *Imagine it's a teeter-totter:* All the area of the rudder behind that pivot = force pushing torque against your steering (fighting your motor) but also is trying to self center/stabilize All the area ahead of the pivot point is _trying to turn the rudder_ and makes it more bitey/turn inclined. ... In your design, you actually have extra lever arm increasing the negative effects of an unbalanced rudder. *You **_don't_** want a 50/50 balanced rudder for 2 reasons:* 1 it's not self centering/stabilizing (boat would want to slew and dart too much vs drive straight). 2 it's actually _overbalanced,_ because the front actually loads more (runs in higher pressure). *A good rule of thumb for a (from a side view) D-shaped rudder is 1/3 of the area in front of the pivot 2/3 behind.* You don't have to be exact, but if you do this, it will work better and you can actually put a larger rudder size for the same turning motor and it will flex your lever arms less. (ps the curved side of the D-shape goes in front, the square side aft) (note: concentrating the thrust in the middle by swapping screws will also help your steering, because the rudder will be in the pressurized thrust, especially so if you use a balanced rudder design)

[@stevehartley7504]

Duct the screw. The Archimedes screw works better when enclosed. You can the use it like an impeller and also duct the outflow to provide steering or put larger rudder fixed just at the outflow. You could also put hydrofoil at front to reduce drag too! This will also ease the ability to turn and provide stability in the water

[@mattbridges385]

Your boat is missing some sort of Keel to keep it moving straight. As for steering your propellers are creating so much turbulence behind the boat, the rudder wont work, the reason it works in reverse is because the rudder is actually doing something. I believe many ships like this had a rudder behind each screw like a sub to control the direction of the water flow coming off the props. These small changes could help solve your troubles

[@mehdiw8924]

The reason it work better in reverse is because when the scrolls "pulls" water, it is pulled in a laminar flow. That's why they pull air in a wind tunnel, this way they get a laminar flow in the tunnel. In his case, it maybe better to control the steering by adjusting the speed of each scroll accordingly.

[@larrybremer4930]

The problem is the hull shape, period. With the power available you need a planing hull rather than a displacement hull. A displacement hull has a speed completely determined by a formula based on the length at water line. Once you push a displacement hull past its design speed it will pitch under (pitch pull) and/or roll violently enough to capsize. A planing hulls shape instead works to lift the boat out of the water leaving a depression behind it (that is actually as long as the hull would need to be to move at that speed with a displacement hull). The lousy hull shape and that instability at speed is completely overwhelming the rudders ability to control direction. The other issue is with one shared controller you are probably not getting symmetrical thrust from the two screws. Using a gearbox to ensure uniform RPM would likely help with directional stability once the hull form issue is fixed.

[@65bug519]

Lots of fun playing with boat designs, there was a successful version of screw drive where the screws were mounted up into the hull with only half below the hull surface and independent motor control for steering.

[@AnonyMole]

So, you've discovered why we don't use multi-rotation screws. 1. You're moving the same water with every additional rotation rather than move a water unit just once. Sure lifting water on land with an Archimedes screw makes sense, but on a boat, you only want to move the unit of water once. 2. The forward 360° rotation will induce turbulence for the following screw rotations ending up in each additional screw cavitating -- spinning without inducing thrust. So, say, you would take the 10 360° screw rotations, cut each one out making them singular (a normal propeller), and mount them side by side. You can imagine that each now moves its own independent unit of water, no leading cavitation exists and you'd get 10x the thrust.

[@kevinmalec4977]

I think one of your motors is losing sync and causing the thing to turn and capsize. you can hear the motor start "screaming" when this happens - the faster one is what the esc is locked to (more voltage from the faster motor), and the slower one is vibrating randomly

[@theunholyghoster4293]

Very cool concept and I'm glad someone tried it. Here is why I think your performance was not as good as you may have hoped. When the screws turn, they grab water and push it backwards, but because the flow is not constrained it ejects the water out sideways. Some of the flow hits the hull, pushing the back up slightly along with the escaping flow downwards cause the nose of the craft to push downwards. (Left and right escaping flow cancel eachother out. Two suggestions, constrain the screws in a tube or box to prevent escaping flow, and make a progressive pitch screw thread, (aka small thread gap at inlet and a large thread gap at outlet). Doing this you'll convert your screw drive into a jet drive and the progressive thread pitch allows the water to reach higher output speed as it gets sped up more gradually.

[@ThatPawikBoy]

This invention will surely push the whole civilization. Possibly we can even generate electricity the new ways. You deserve a Nobel prize.

[@ThatPawikBoy]

I don't want to insult him or anything. I found his channel through 3D printing sites and I really enjoy him and the content he creates.

[@argaard]

Reason because of your rudder is not working when moving forward is that it needs laminar flow to work properly, and your propellers are making the flow turbulent when spinning fast. Indeed, your boat is steering better when slow and when moving in reverse. You might try to move the propellers more towards the bow.

[@kopaxson5202]

With all your experience printing pumps, can't wait for you to do something like this with a pump for jet propulsion like a jet-ski. I hear they usually use impeller pumps but not entirely sure. Prolly depends on the jet-ski. Slapping a super heavy (like steel or brass or something) thick fin, aka a "keel", under the boat would make it a million times more stable I'd think.

[@CommodoreFluffy]

in the future you can increase stability of small boats with a keel(hydrodynamic or weight), outriggers, or a catamaran design. to increase rudder authority you need a larger control surface. alternatively with a dual thrust system you should consider using thrust steering at least at low speed where the rudder will have least effect

[@MCsCreations]

Fantastic work, dude! Nicely done! 😃 Stay safe there with your family! 🖖😊

[@ziggybombers1563]

I do love your videos bud please make more. Your wacky inventions are bloody great 👍.

[@GhostRyderFPV]

I've been using hobby $ESC's and brushless motors for a long, long time. I've never once seen anyone wire two motors in parallel to one ESC before. That's uncanny..

[@xlucioflavio]

You should add a "regulator" system to adjust the inclination of the screw propellers if you get more thrust. The problem is that the propeller running parallel to your boat will maintain a larger area of contact with the water, making it more frictional and therefore slower and even sinking (Coanda effect). To avoid this, it is necessary to slightly adjust the pitch so that the bow of the boat rises as the acceleration increases. For each type of vessel, an angle is required, so a way of adjusting your propeller is required.

[@TheRealBanana]

With regards to set screws in plastic, I've found diameter is most important for holding power. If you are limited in diameter then you need length. If you don't have either you're in trouble. Hole size also matters, you want to have it as tight a fit as you can without it being to difficult to screw in. Sometimes a larger diameter lead-in can ease installing into very tight holes. Lately I've been using M5 set screws with an undersized 4.7mm hole with at least 4mm thread depth in the plastic. This has worked fine for securing D-shaft motors to gears and as set screws for holding PVC pipes in place. The material I'm using is PETG. Also you might try slowing down one screw to create drag on one side as a means of steering.

[@michaelstanich3429]

If you're looking for suggestions, a larger rudder and another esc so you control each screw independently. That may allow you to ditch the rudder, it seemed to have decent power in your tub before the wiring correction.

[@SpeedyGonzales-jn3kx]

When I first started watching the video, I assumed he was going with dual ESC'S for exactly that purpose.

[@NarcoSarco]

Nice video! The comments are only made of suggestions, so heres mine: Battery is way to far in the front and threatens to sink the tip, making it hard to controll, easy fix, move battery back :)

[@johndough8115]

Id like to see an attempt at making an Air-Bubble Anti-Drag system. You would alter the Bottom of the boat, with length-wise "channels".. about a cm of depth. Then you drill holes at a +45 degree angle... about every inch, in the center of these channels. (The boat itself, would have an inner and outter hull.. thus, preventing it from sinking) These drilled holes, would release Air Bubbles... which would add "Lift" under the boat.. as well as potentially act like "Bearings".. helping it glide through the water, much easier and faster. You would either have to force air from front collected scoops... or... use some sort of air compressor system. That said... it might also be worth trying with low-pressure water, instead of air... I just think that the airs buoyancy, might help greatly in helping with something like a huge, heavy, Cargo Ship. Helping to reduce the weight to a certain degree... and again, to potentially act like an anti-frictional bearing. To test this, you probably want to use a boat large enough to sit in, and piolet. As anything smaller, would be hard to tell if there was any notable effect, due to scaling issues. Even a modified Canoe, might be fine. I will say that a lot of small boats pop up for FREE, on craigslist. The most simplified version, could just be having the air going under the boat from frontal feed pipes... and the Channels would allow all trapped air, to run from the front of the boat, to the rear. You would just need to make a way to equally divide the air, and guide it to each of the channels.

[@johntoves9015]

What's your recommendation for a hobbyist getting into printing? I have 2 kids under 3 so less maintenance would be great.

[@StepSherpa]

The reason why the rudder worked better bakewards is that its no longer in a turbulent flow, pretty sure the water behind the boat ended up being quite low pressure. Think the reason why it might want to capsize in one direction was maybe related to something being misalgined, maybe inertia but it shouldnt be an issue due to the different directions of the motors

[@DD-DD-DD]

It looked like there was a power imbalance between the two impellers. But it changed sides at different points in the video...

[@Flt.Hawkeye]

The Arimedian screws are way more efficient at low rotational speed. When using this kind of Propeller for porpulsion you should use low Speed and big Props to get the best effect or you duct them.

[@GBCobber]

Those bearings at the prop ends are it's death. Gotta be losing more than half the thrust right there. Wouldn't a simple needle suffice as a bearing there?

[@fireheadpet2039]

This is such a great experiment! Didn't know this was the birth of water impellers. I believe aa Soviet inventor built a tractor on that principle. Really enjoy your videos!

[@metalink]

exactly what i was thinking. Then direct flow right or left for direction using a variable nozzle

[@finleymakee4850]

you should try putting the screws on two really long arms that make the boat wide so you can do tank steering

[@FrancoisMathieu]

I love your projects, they are very informative and fun to watch. Thanks :)

[@maverickstclare3756]

a fin keel will stop it rolling, also very simple to add on that hull

[@corbymodelboatclub]

Interesting use of an Archimedes screw. If you made them wider apart and the full length you could probably crawl out of the water on to land. Always good to see people trying out things and being a little inventive.

[@Knapweed]

The reason the boat keeps going on its side is because both propellers are producing torque in the same direction. They need to be going in opposite directions just like the props on a twin engine motor boat, with the top of both props rotating outwards.

[@SuprSi]

Scrolled a long way and didn't see many people saying.. You *really* need an ESC per motor, you can't run brushless motors in parallel, it's amazing they're working together at all! That's why they keep doing weird s**t like starting backwards or going out of sync.

[@susie3702]

For the best result make a left-handed screw on one side and a right handed screw on the other side due to you having 2 screws of the same direction as soon as you rev up the motors the Torque produced tryes to rotate the boatwith different direction screws they will cancel out the oposite direction torque.

[@khaosforever5034]

"It might blowup, but im 20% sure it will not." I like those odds! Let the testing begin!!

[@CurtisTarwater]

Nice project. Definitely need a keel with some weight for pitch. Weight distribution (battery high and forward) is causing the front to submerge. Maybe consider a single step hydroplane design or tri-hull for stability. 🙂🙂

[@darknessnightfall]

great humor while doing great tests

[@rockyBalboa6699]

Very interesting and Educational video!

[@jonathanlunger2775]

I still want to see a gokart made with the large version of your electric engine. What do you think about trying a bell shaped housing to "squeeze" the water passing through it? Since water doesn't compress, it should speed up as it gets further back in your prop assembly.

[@MrHolozip]

It looks like the prop wash runs to either side of the rudder, so it struggles to redirect the water to turn. You could try a double rudder mechanism placing each rudder surface in the middle of the prop output perhaps?

[@3DhobbyUA]

incredible ) now i understand why it so difficult to create some product

[@JM-dp9xl]

Nice work. Try 2 rudders with a linkage bar and you'll have more fun

[@GeddyRC]

I love this channel. Seriously one of my favorites. I like seeing you go through the troubles and figuring out solutions. Nice job with this one!

[@ArmanRC]

great project my friend, keep going to the perfect result

[@ScarabChris]

You have a LOT of drag where the motors mount. You need to put some really long and sharp cones. Otherwise, the faster it goes the more drag and the more unstable. This is why the fastest boats have surface drives so when at maximum speed the only thing in the water is the bottom half of the propeller. The screw drive will work at lower speeds, but not at high speeds. In fact, you would do better running that thing in snow. LOL

[@stanleydsouza6723]

Fantastic, 👌 👏 Amazing 👌 👏..

[@medienmond]

Cool that we get to see failures in your projects, too. This might help some people not having to make them again by their own and save humanity some time for more important things...

[@TheWayneStevenson]

Slick! Do you have the STL of the screw props available for download?

[@markclark4154]

I suggest redesigning the support at the end of the screw to be more hydrodynamic. It is blocking off a lot of the thrust.

[@futurizonfr3368]

I'm surprised that putting the motors underwater doesn't seem to be a problem. Are they waterproof?

[@meeself]

Yes, he stated this in the video

[@materialdefender3599]

"The motors will spin for fun"😂

[@johnknoefler]

You need a tube over screws because opposing screws force water out and mostly down. That's why boat flips over. Better yet, you only need one turn on screw to reduce drag. A screw in a tube produces more power.

[@polopup]

try the hunt for red october version. put the screw propellers in their own tubes and see if it's easier to propel. maybe quieter.

[@davidjulian8536]

The trouble you had with the bad rudder control and capsizing is because you printed the rudder back to front. The foil shape was nice, but the thin edge shouild be at the back! Also if you made it less deep and a bit wider it would be less likely to tip the boat.

[@Anonymous-jm3mg]

As with dual propeller propeller boats, the props have to spin in opposite directions and the tiller controls the steering. This being a test, I'd switch to jet drive which is basically a screw encased within a tube. But that'd defeat one of the purposes of long torpedo screw drives. If they were buoyant, a vessel utilizing this system could be good for swamp expeditions because these screw drives would crawl over the muck like a tank.

[@Deebz270]

The steering issue is down to a single, narrow rudder (more appropriate to a sailing rig than a power boat...) sitting between two highly cavitated prop-streams. Thus very little water-pressure enacting upon the narrow rudder surfaces. A broader aspect ratio, twin-rudder assembly centred on the prop axis would have been more efficient; or differential 'screw' steering might be another way to go; though the torque of those motors might require some careful tiller/joystick handling. The hull form isn't really suited to the prop design/torque/screw pitch, especially compounded by aforementioned zero-helm rudder design. I would have enclosed the Archimedean screws in a tube - making essentially a hydro jet, with twin-nozzle servo-steering and placed the battery pack further aft, to bring the bow up, that way, it might just plane...

[@justinwalker923]

You need to be able to control each screw auger independently. Have one in reverse and one in forward to be able to steer.

[@goodisnipr]

The problem is that the water is being pushed away from the screws in all directions. Put the screws in the hull of the boat with an ingest and exhaust port for each so that the water only goes backwards and then the boat will really move forwards.

[@martinh2783]

I think you would get more stability if you swapped the screws so that if one screw gets out of the water the torqe from the other one will push it down again.

[@kellyd6195]

Neat project. Thanks f I may make some suggestions. First, make it into a trimaran, for stability. Also, your rudder seems kind of small and the turn too much. When you go all left/right, the rudder is acting more like a brake than a steering device. Plus, the rudder being small and in the center, it doesn’t give it much steering authority. Keep up the great work!! Just a thought, if you enclose the screw propellers, could you make it more like a jet ski?

[@onhazrat]

🎯 Key Takeaways for quick navigation: 00:24 🚢 The first steamship driven by a screw propeller was the SS Archimedes in 1837-39, marking a significant shift in ship propulsion. 01:05 🛠️ The boat for this experiment is made from cheap and lightweight EBS plastic, designed to float on water. 01:54 ⚙️ Brushless drone motors are used for propulsion, as they work well underwater and avoid issues with brushes. 02:37 🔩 Set screws and extrusions are used to securely attach the propellers to the motors to prevent slippage. 03:38 🧰 Electronics control the motors, and a 3S battery is used, with a custom hole cut in the boat hull for battery placement. 05:14 💡 PCBWay offers 3D printed screw propellers, CNC machining, and more for various projects. 07:15 🔄 Wiring issues required swapping motor wires to achieve the desired rotation directions. 09:55 🌊 The boat experienced unexpected instability and capsized during testing, prompting adjustments to improve control. 12:58 🚤 The video concludes that screw propellers like the ones used in this experiment are not recommended for practical boat use due to their cheap and unstable nature. Made with HARPA AI

[@mark8664]

You could use an oscillating multi tool to cut the hull of the boat.

[@user-ju9zo6ws2l]

Схема с архимедовым винтом хорошая, но не доработана. Чтобы сделать рабочей, нужно сделать катамаран и винты расположить каждый в своём корпусе. Чтобы был настоящий архимедов винт, нужно каждый установить в широкие трубки. Входное сечение сделать больше и вообще поиграть с диаметрами. Выходное сопло сделать регулируемым. Конечно в результате получится два водомёта, если сделать три корпуса и три двигателя с архимедовыми винтами, будет ещё устойчивее и круче.

[@xKatjaxPurrsx]

hehe...when you put that comically small rudder on the boat XD

[@adrinaik93]

I would have made the whole platform wider, that way it would be more stable and would mitigate the torque roll that is making it capsize, and made the bow taller (it is dipping the nose in the water), as well as adding some sort of keel as a pivot point to be able to turn. Apart from that, interesting to see those propellers in action!

[@SupaGEEKDesigns]

A duct would help a lot, although tough to design properly. The other thing is the speed of your screws is way too fast for your screw pitch. At that speed you should only have 1 pitch. Multiple pitches at that speed will only trap air instead of pull water. That's where the duct comes in....

[@AurynGaming]

The boat needs to be wider and maybe use pontoons or Catamaran style boat? Also surely you would either 1 screw plus rudder or if you use dual screws then you would stear with the screws going in the opposite direction, lot more stuff you could play with and test here - you have most of the stuff already so you might as well dig deeper!

[@blanchae]

I was thinking the same thing.

[@richardbolger5140]

A keel will give you better handling and if you make it from something like lead it will stabilize from rollover

[@EasyThere]

Have the screws both spin towards the center and move them out to the edges.

[@pancudowny]

You need to put some winglets or outriggers on that hull, so it don't flip while turning under full power.

[@Mirabove_DK]

Try to build the Propellers in a housing like a screwcrompressor, with a outgoing nossel for stering

[@twiztedmowers2]

Wonder if you spread the propellers farther apart it might help with tipping over.

[@carbide1968]

love the idea but way way to narrow design. also 2 smaller rudders one each screw might help? do you think spreading the screws out and rpm change on each screw , could help steering? also the bow is diving which won't allow steering.

[@ramonedrozojr.768]

why did your ESC catch on fire? overcurrent? shorted?

[@chaseleim4773]

Compressor pumps, makin a tube for them to sit inside and slowly taper it down in size

[@alexlikos2327]

If you make your rudder 2-3 in long, and keep the maximum swing distance of the rudder servo like 50-60 degrees left or right, you'll have a lot more control Also, if you put your screws half an inch, to 1 inch deeper, they will create less cavitation and give you more power

[@user-tf1oo9rj6u]

50-60deg is too much and well beyond the stall point of even a foil shaped rudder, where lift aka turning power significantly diminishes vs a lesser angle. I'd suggest 40-45deg max, with erring on the side of less is better.

[@NelsonCastillo]

Great video. I think it should be easier if the props are in front and not in the back, I say it because of experience with RC planes. Your test driving backwards suggests this as well. On the other hand, easy on the throttle! :-) You also might need to tilt a bit the props, not sure how the center of gravity affect boats and propellers.

[@gottagift]

I am thinking one reverse thread prop that rotates in opposite direction of normal thread prop. Two props with opposite properties.

[@user-tf1oo9rj6u]

Tilting is a very good suggestion, as he has a problem with the front not coming up. He would just need a little spacer near the front to accomplish that.

[@mustafaduhanadguzel1811]

You should arrange your motors to work in opposite turning direction. When you speed up, moment of inertia causes to ship flip over. When you arranged the motors, you should arrange your propellers like the motors. Otherwise your propellers would act one forward one backward. Besides, loved it.

[@JointerMark]

I wonder if the screws were mirror images of each other so while the motors could be turning the same way the screws would be turning opposite of each other...like a right-handed screw against a left-handed screw?

[@idvistream]

. maybe you need tube outside the propeler, than the propeler will works like pump, moving water from front to back, i think you will have more thrust

[@johnedwards3621]

Use twin ducts and differential motor control for each side with a heading reference. Add a NACA scoop to draw the intake, stream line the rear bracket and try to get rid of the rudder which is why the stern was pushing the bow down. Also a hydroplane step on the bottom, Air drones got their start a long time ago when some military officer who happened to watch R/C models. You have a great attitude -- lead, follow, of get the hell out of the way. Kind of Elon-like.

[@fluiditynz]

After many years with RC jetboat design there is so much here that shocks me😂The streamlining interruptions, the extremely high drag low pitch options, unprotected motor bearings and ESC, I am truly shocked. I suppose it's an excuse to have a streaming channel though! I'm 57 so I've had plenty time to learn from my mistakes. Seeing as you are pimping out PCBWAY, I suppose I should see if your SW or HW design compensates 😉

[@fluiditynz]

OK, after checking, you're the pump obsessed 3D printing guy. I'll try to be helpful and not bring up things like software and hardware. 1. Replace your metal motor bearings with ceramic ones or after and before every run, lube with CRC/WD40. 2. shorten your prop screws, no overlap threads required, they only create horrendous drag. 3. inject neutral cure(very important) silicone into your ESC heatshrink and LiPo batteries. 4. use bluetack or similiar around receiver wires and doublebag seal around the bluetack. Streamline everything. I understand you are going retro with the screw props but seriously, the drag! way too many revolutions! I did it as a child with a small brushed Mabuchi motor and a spiral of rifling swarf but avoid. its really draggy.

[@fluiditynz]

And another thing. Camera centre of gravity way too high. You also need to bring centre ofgravity between 1/3 and 2/5 from stern. Your steering fails because pivoting should be around the rear, not the front and you will never get good speed with weight too far to front.

[@gottagift]

nice project. Sorry to see the loss of efficiency on screw with higher turns per inch. I would have resorted to dual rudders and variable speed in each prop. For added fun, two plastic butter knives penetrating through starboard and port hulls at the aft.

[@bkhizar]

The boat must be large enough to counteract turning or toppling because the propeller take a large space of boat section making an large unstable end

[@surajmal9775]

are all bldc motors waterproof?

[@kaifailo1452]

Screw propellers are suitable only for propulsion of solid or cement with high density,not for water with much lower density.

[@andymuzzo8568]

You should put the screws on as an outrigger configuration.

[@NiksSofa]

I would be curious about a follow up: what happens if you enclose the screws in a pipe open to both ends?

[@adriancomanescu7880]

Use 2 concentric tubes to make stability and not lose power, think about Coandă effect

[@gilb6982]

You need a kind of wall between the two rotor it should be a bit longer than the rotor and go deeper into the water then the rotor This way you remove the turbulence from one rotor to the other and you can use the speed of each rotor independentely to steer and if the wall is deep enought it became a queel that balance the boat . At the very least it is what i think i would like to try with that kind of idea ! Thank !

[@pancudowny]

Try designing the screws so they're progressively deeper in pitch, like I've once seen in a blurb about making a more efficient water propulsion in Popular Mechanics.

[@lightmare3362]

Hello, haven't you considered why you can control the vehicle backwards and not forwards? Your rudder is built upside down. Build it again and this time the cross section should be rotated 180 degrees. The surface of the rudder must also be adjusted. Maybe a little bigger.

[@gerthalberg9735]

The boat rocking must be caused by torque - perhaps you should let the screws rotate opposite directions. I.e. one turning clockwise and one counterclockwise

[@paradiselost9946]

surprised it did work as well as it did. the main issue with a prop is that the water moves. they dont screw "through" the water, they fling it backwards... and outwards. always outwards. as the pitch increases, you get less backwards, and more outwards. a "normal" prop, they did a lot of work on blade widths versus thrust versus power input in the early years of powered shipping, found theres no point going over 30% or so disc area. a big issue with an extended screw is the water flinging outwards at the start of the screw displaces water... that has to come from somewhere. cool, it comes from directly in front of the screw. but move along the screw, and the water is still being displaced radially outwards... now wheres the displaced water coming from? the water prom the previous turn of the screw backflows, fills in the void... cavitation goes out the roof... meanwhile, you have to consider the stationary water around the whole thing. by flinging water outwards, you accelerate all that mass of water that has absolutely nothing to do with you or making thrust. its turbulence. its drag. then at the end of the screw theres a flat bracket at right angles to any flow one created., obscuring 1/3rd the flow and making it produce... more turbulence. its been a well established fact for a long time that the fluid behind a propellor contracts in proportion to its velocity, and the maximum efficiency is reached when the contraction is close to 2/3ds the disc area. whether its a boat or a plane, the fluid acts much the same way, a contracting stream. its just like betz limit, in reverse. its the same principle. an inefficient prop flings water outwards and wastes a lot of power. a highly efficient prop produces an extremely laminar "tube" of high speed, low pressure fluid, SMALLER than the prop disc. would be interesting to do this "inside out"... tubes running through the hull. the water CANT fling out, and the only place it can come from is the front. you also eliminate the tendency to "prop walk".

[@somelivingthing]

I love your projects! They always make me want to blow the dust off of my 3D printer. This one happens to fall within my area of expertise. Your rudder is rather small, and quite a lot of it is above the water line. Also, the hydrofoil profile is backwards. The sharp point (normally the trailing edge) is pointed forwards, this needs to be flipped 180 degrees. This design does not take advantage of the hydrodynamic properties of the rudder, and basically just relies on drag, very close to the centerline of a long hull, which does not generate enough torque to rotate the hull well. This is also half of the reason why it turns better going backwards. The other half is that you create an unstable system i.e. read about aircraft with canards.

[@dpgedward5947]

If you spaced the propeller further apart and controlled the power to each you would have better balance and would be able to steer without rudder

[@maybejoshh1907]

you dont have any pontoons to stabilize, the hull is very narrow for the amount of rotational force the screw props will create. If you add pontoons on the sides of the hull is wont tip over so easy. also counter rotating props when using two at the same time is important.

[@kylebooth2528]

You need a longer or deeper rudder. Right now it's just sitting in turbulence so it isn't going to do much.

[@snekmeseht]

Dude, you need to cowl the upstream side of the screws. The leading wall is like big water brakes.