[MOC] Cyclorotor Tow Boat (Voith-Schneider inspired) (NEW funny prototype)

[JoKo]

Hi!

For this boat I used the 5848 yacht hull. I closed the nothch at the rear with bricks and electrical tape.

The propulsion uses two vertical rotors with thrust vectoring, like the Voith-Schneider Propeller (VSP)(https://en.wikipedia.org/wiki/Voith_Schneider_Propeller), but the mechanism is totally different.

The rotors have two bades each. The blades rpm is half the rotor rpm. This makes the blades to "swim". The rotors are monted on small turntables allowing the steering axle to be coaxial with the rotor. This axle controls the12t gear at the center which steers the trust direction. In theory you could steer it 360° keeping the rotor rotation. For Control + I used the rotor turning backward for reverse and I can steer the axles ~220°. The orange wedge at the top of the rotors points the direction of thrust (forward).

The thrust is obviously asymetric to the rotor but the rotors are counter-rotating giving the boat a centered thrust.

This asymetry combined with the position of the rotors (~1/3 front) on the boat allowes  for exceptional maneuvrability , just like the VSP.

Steering 90° forward pivots the boat on its z axis and 90° backward pushes the boat laterally.

 

The naked boat:

 

Rotor:

I have experimented with other mechanism, closer to the VSP, with the blades keeping the same leading edge along the cycle. I had help for that from @1980SomethingSpaceGuy which came with a nice solution, but that's a story for another day!

 

Edited June 27, 2022 by JoKo

[Davidz90]

Very interesting mechanism! The maneuverability is absolutely amazing.

[Jundis]

The movement at the rather slow speed of the propellers is superb. I am really amazed at you idea!

I think @efferman build one of the Voith Schneider ones a long time ago...?

[Milan]

Rarely seen propulsion system!
And love the inclusion of Secret of the Monkey island

[JoKo]

1 hour ago, Jundis said:

The movement at the rather slow speed of the propellers is superb. I am really amazed at you idea!

I think @efferman build one of the Voith Schneider ones a long time ago...?

Thanks! yes slow speed is pleasant to watch!

I found @efferman's VSP. As close to the patent as possible! Beautifull but nothing functionnal. Except if I miss something, only paddlewheels.

[efferman]

Congratulations. Works pretty Well.

 

[Toastie]

This is really extremely nice!

Never heard of that mechanism - but then I have never heard of many other things here in the Technic forum.

How did you do the motor control? Using the PUp remote and then setting manually the speed of the motors? Or do you have some sort of "power" and "rudder" dial, which lets you do things semi-automatically?

Really nice. Congratulations on making it work such impressively! 

Best regards,
Thorsten

[JoKo]

5 minutes ago, Toastie said:

This is really extremely nice!

Never heard of that mechanism - but then I have never heard of many other things here in the Technic forum.

How did you do the motor control? Using the PUp remote and then setting manually the speed of the motors? Or do you have some sort of "power" and "rudder" dial, which lets you do things semi-automatically?

Really nice. Congratulations on making it work such impressively! 

Best regards,
Thorsten

Thanks a lot!

Voith-Schneider is a weel known system for boats since ~1930. However my system is a real MOC. Never seen this or heard of before.

My first try was with IR Power function with two non-progressive channel.

One motor for rotating the rotors and the other for steering the two rotors together via wormgear. steering was by trim and I needed to see the orange arrows on the rotors to know where I was.

Now with Control+ I use a ControlZ custom profile with throttle by slider or step by step and steering with a long slider with marks at 90°. It is indeed semi-auto.

[Johnny1360]

Very cool, I wonder how well this could work with a larger, or smaller hull. I very much like that mechanism you created to replicate the real thing.

[JoKo]

1 minute ago, Johnny1360 said:

Very cool, I wonder how well this could work with a larger, or smaller hull. I very much like that mechanism you created to replicate the real thing.

I would like to try with a 60266 boat hull. Or better two of them. It has a hole in the middle and could be the perfect fit.

It is also possible to fit it between a catamaran's hulls.

[Toastie]

58 minutes ago, JoKo said:

It is indeed semi-auto.

I am in total love with this.

The combination of a very nice and well-thought-out build - the mechanical hardware - in combination with rather powerful electronics (the electronic hardware) - in combination with your very nice software - for me - clearly demonstrates a) what is going on today out there and b) the future. It is the combination, that makes the difference (for me).

A true Technic project! 

My world. Thank you very much for sharing!!!

All the best,
Thorsten

[Johnny1360]

Couldn't agree more and the gears are already turning, some great ideas to work with.

[1980SomethingSpaceGuy]

Brilliant job! I especially like the bluetooth version, because it allows low speed for the rotor and in this mode, I find the ship's movement quite elegant!

@JoKo 's shot on a cyclorotor is very pragmatic and efficient, but not strictly speaking a Voith-Schneider. That's why I came with a better approximation on my own:

 

The red 3L liftarms represent the thrust vector. Which are coupled and controlled with a continuous motor. The funny thing is the behaviour is not quite the same should you point forward with the vectors and rotate the rotors in one direction or with the vectors backwards and the rotors in the opposite direction. In all of our prototypes, the tendency was to behave more like a normal boat in forward mode and more like a drone (able to move laterally) in reverse mode, allowing the wide range of controlled movement as visible in the first video of this topic.

My version has less aggressive angles of attack for the blades, which in real life would mean less cavitation and more efficiency, but here, it is just weaker and slower.
With the above versions (that were later improved, these being prototypes), mine was marginally easier to steer, but the bluetooth version @JoKo showed in his video is by far the best of all of our cyclorotor prototypes.

Anyway, I love this kind of projects; creative part usage and mechanical design to build something that is fun to play. I think we did a decent job with only 2 on/off channels on these remotes 

Edited June 25, 2022 by 1980SomethingSpaceGuy

[aeh5040]

Great work!

I actually made a rudimentary boat using exactly this basic design of "pseudo-VS" drive about 15 years ago, but never got round to perfecting it. Mine was very bulky (these fins were not available), so I only had one propeller and could not do the counter rotation, plus power functions badly limited the range, etc etc.

You have turned the same basic idea into what it should be!

 

[JoKo]

26 minutes ago, aeh5040 said:

using exactly this basic design of "pseudo-VS"

Which one? My "swimming" rotor or the one by @1980SomethingSpaceGuy?

[aeh5040]

2 minutes ago, JoKo said:

Which one? My "swimming" rotor or the one by @1980SomethingSpaceGuy?

Yours. I think I had four blades. But the gearing system was essentially the same. It was also pre- small turntables!

I recently thought about doing a monster version using Osprey blades too...

Edited June 25, 2022 by aeh5040

[JoKo]

3 minutes ago, aeh5040 said:

Yours

Now you know I was à good idea!

I think at this scale and with that kind of motor (slow with high torque) it is better than real VSP.

I mean my boat was faster than it opponent. Testing is still in progress.

[mahjqa]

Excellent model! Really impressed by the manouverability!

[GerritvdG]

Really cool projects @1980-Something-Space-Guy and @JoKo!  Thanks for sharing it here.. 

[JoKo]

In order to continue research an developement I built a new prototype.

With this project I wanted to use the cyclorotor mechanism that @1980SomethingSpaceGuy used on his "VSP" boat.

I used it a different way to spice up things and use a non-Lego buoyancy device. I found a cheap buoy duck with a horseshoe shape and built a frame on it.

I placed a huge rotor inside the buoy with two big blue blades. I had to modify slightly @1980SomethingSpaceGuy's system because I had no clearance around the rotor.

The main rotor spins slowly and the direction of thrust is controled by a servo.

At the rear of the "ship" I placed a small, faster rotor which thrust is locked laterally. The secondary rotor's puropse is to cancel the torque produced by the main rotor. See it like a helicopter tail rotor, but with cyclorotors.

A custom ControlZ interface controls rotors speed independently and the direction of the main rotor thrust.

 

On the water it is slow and nothing easy to control. steering is achieved by rotor speed variation and the trust vectoring allowes some kind of lateral movement. It's very sensitive to wind, the head is pushed in the wind's direction.

I have to admit I'm not proud of the poor performance but I'm pleased with the comical aspect and the beautifull underwater ballet of the blades.

 

[Edwin Korstanje]

Love the way you got the idea after a Voith-Schneider prop system in a small two prop system and it works great in your video. I tried it on a biggers scale on a 8  blade, but was to big, but @efferman build a true working Voith-Schneider some 6 ore 7 years ago 

Maybe you can ask him how he have done it in full indepandent pitch all the blades

[efferman]

How my version works (Ten years ago)

The Prototype in water

and the fat tug

And type two with side by side propellors

 

Edited June 28, 2022 by efferman

[Edwin Korstanje]

@efferman sorry in my mind it was 7 years ago, but 10 years ago to make a Voith Schneider was stunning for these days. @JoKo did a great job and is almost close to a Voith Schneider and works great. I failed in 2013 for the model Staeldiep ferry and was to big to use it.

Build 2 models in 2014 later my biggest working Technic model the SL Gabon where almost everthing was work at trusters, working winches ancors lifting,towing pins and radar all remote PF controle also all official Lego lighting and a complete interieur. But you are the master in technic 

Edited June 28, 2022 by Edwin Korstanje

[efferman]

8 hours ago, Edwin Korstanje said:

@JoKo did a great job

Yes, he did.