Super cavitating very high speed stealth surface vessel

[Len Morris 2Participant @lenmorris2]

Hi Paul,

Been following this on the sidelines. Brilliant project and quite gutsy!

Worried about your Ghost at rest drawing. COG's and metacentres. I think she'll roll for England with the sponsons totally submerged. Welcome to the world of neutral buoyancy!

Agreed the main weight needs to be in the sponsons. Have you considered hydraulics / pneumatics to flap the wings?

Don't see the load on the hull being an issue. Why not engineer the mechanism as a stand alone item with the internal stresses contained and then build the hull around it?

Len

[Bob Abell 2Participant @bobabell2]

Welcome to the Land of Make Believe, Len!

You will be in your element on this thread, coming from the Land of the Head Bangers!

I think, Paul has shown the sponsons submerged as a trap for the unwary Clever Clogs amongst us!

I assume the model is travelling at speed and is staying airborne due to the wing effect or his trusty Magic Wand

Suggesting Hydraulics or Pneumatics qualifies you for Forum membership

I think we've got a solution for the Orrnithopteral feature……His idea or mine

Stick around while Paul comes with a solution for the motor drives!

You ain't seen nothing yet!….So the saying goes

Paul may be slightly miffed over my flippant observations, but he can take it!

Bob ………Watching from the side lines , with bated breath

[Mark Jarvis 2Participant @markjarvis2]

HI Paul

I like Lens idea regarding extending the sponsons. what about aircraft retracts, either the compressed air type or the servo opperated type. probobly need upgrading but would be a good starting point.

Mark

[Bob Abell 2Participant @bobabell2]

Thank you Mark

The sponsons need to be powerful

They have to lift the superstructure off the water

Paul is in the middle of his design and is not seeking any further suggestions at the moment

I'm doing the early trials by converting the Brutus model and I have a free hand

But it needs to be a proper job

Bob

[Paul TParticipant @pault84577]

Hello Len

Thank you for your comments and interest in this project, I also thank you for highlighting how complex the calculations are and I expect that you are fully aware and appreciate how much the calculations are affected by variables.

At the moment the calcs indicate minimal roll when the boat is at rest but of course this depends upon the variables of prevalent water and weather conditions.

I have thought about using micro pneumatics / hydraulics instead of geared electric but I wont be able to decide upon a system until the prototype testing is complete.

The load on the cabin comes from resisting / anchoring the force being applied by the wing mechanism, it is true to say that an engineering solution might be designed whereby the load is supported by an internal frame.

Hello Mark

Aircraft retracts might be a solution, thank you for the idea, I will have a google and dig up some specifications so that I can see what the load ratings are.   

Hello Capt Bob

Flippant?

Paul

 

Edited By Paul T on 14/01/2015 15:23:22

[Paul TParticipant @pault84577]

And now to throw a spanner into the works…..

Does Ghost qualify as a CHARC design?

 

Edited By Paul T on 14/01/2015 15:44:35

[Bob Abell 2Participant @bobabell2]

Hello Paul

Don't understand the first three pictures?

How do you get the sponsons to travel at various depths.

Bob

[Paul TParticipant @pault84577]

Hello Chief Engineer

I presume that water ballast is used

But does Ghost qualify as a CHARC…………….I don't think so

What do you think?

Paul

[Bob Abell 2Participant @bobabell2]

Water ballast?…..That's a new one?

How can the sponsons stay neither up nor down?…….Witch craft?

If we can get the wing movement, then we might qualify, but we can't do the hovering trick….Can we?

Got a bad feeling about this

Bob

[Paul TParticipant @pault84577]

Dear Chief Engineer

Don't worry about it ………..the design office understands all about it.

Off to sharpen my crayons

Paul

[Bob Abell 2Participant @bobabell2]

Just spotted the blades on the sponsons on the inside?

Are they elevators?

Bob

[Paul TParticipant @pault84577]

Hi Bob

Here is another spanner in the works

**LINK**

[Bob Abell 2Participant @bobabell2]

Paul

That`s a surprise and not very exciting either!

Are we discouraged?…..Don`t think so

The flapping wings makes our boat different!

Pity we couldn't see the props and rudders etc…….Wonder what was meant by…"Home made jets"?

We need to find more YouTube stuff, before we go to far?

Bob

[Mark Jarvis 2Participant @markjarvis2]

HI Paul

What about water jets, quite common in RTR boats these days, combined with the fins this thing could vary the water clearance similar to a submarine using dive vanes.

Mark

[Paul TParticipant @pault84577]

Hi Mark

Unfortunately the original boat has forward facing propellers so we are stuck with using them. There will be a simple solution to the propeller question I just haven't found it yet.

Paul

[Paul TParticipant @pault84577]

Bob

I have made a simple third size card prototype to test the various shapes and angles, it doesn't answer all of the questions but it does help to visualise how it all goes together.

Paul

Edited By Paul T on 15/01/2015 14:18:39

[Bob Abell 2Participant @bobabell2]

Paul

That`s a nice idea for starters

With reference to your cardboard tubes……How big would the props be?

Could you cobble some up?

If we can`t have contra rotation, we could have a pair of props that look like them?

Bob

[Paul TParticipant @pault84577]

Hello Captain Bob

I should make it clear to the assembled Kevin that the production of a small card model is a little more serious than 'a nice idea for starters' as it allows the designer to better understand the subject.

Its a shame that we cant place bets on this site as I would have won the jackpot with knowing that you would have said…. "How big would the props be" lol …..however I remain poor……but the following photos are just for you as I am sure that these models will answer some of your questions.

Dear Kevin

I know they wont answer all of your questions and I am sorry that I cant yet tell you how big it will be, or how the cavitation system will work, or how does it turn without rudders, or are we alone, is there a god, do fairies exist, do we need the moon, why is water wet, why do aliens travel millions of light years only to meet backwards americans in the backwoods.

et tu

 

 

Edited By Paul T on 15/01/2015 16:07:48

[Bob Abell 2Participant @bobabell2]

The models look splendid, but too slender to house any form power source?

Bob

[Paul TParticipant @pault84577]

Hi Bob

On the real vessel they contain gas turbines and we have seen that the boat goes like stink so they cant be too slender.

Don't worry Captain as its all under control

Paul (getting cold up here now)

[ashley needhamParticipant @ashleyneedham69188]

Didnt realise/wasnt paying too much attention to the floats they are v long. The beauty of a prototype, puts things in proportion.

Didnt bother studying initial pix, to see that props at the front. Makes supercavitation very difficult, would require special prop form ?? Prev youtube vids seen demonstrate supercavitation of a body travelling through the water. What we have here is a prop supercavitating..gosh.

Any ruddery things would be tricky if/when the wings move as the angles would change.

Ashley

V interesting.

[Paul TParticipant @pault84577]

Hi Ash

I knew you weren't paying attention………that's the problem when you sit at the back of the class and doodle saxamaphones.

Sponsons are very long in relation to the cabin but on the plus side there is plenty of room for motors and batteries.

The cavitating system is the only thing that I haven't sussed out yet but I will have it sorted by Monday.

At the moment I intend the steering to be tank style but I'm not sure that the reaction times will be fast enough so I still have some work to do.

Paul

[Dave_PParticipant @dave_p]

They would look just at home in space as in the water to me.

[Len Morris 2Participant @lenmorris2]

Hi Everybody,

Well this post is off like a supercavitating rocket, must be all the hot air!

Bob A – Your response made me fall of mi chair laughing! Well done you. Made mi day!

Making the wings flap – The Germans are now making some incredible engineered kits for model trucks and digging machines. Saw a Cat loader and a dump-truck the other day. Both were the size of say half a washing machine. They were exactly scale and worked in every detail. They were much too heavy to pick up yet the real scale hydraulic cylinders of the loader would easily lift the machine of the floor in a fully proportional manner. Not cheap. Six grand for a finished model but all the bits can be bought separately as your budget allows. Might be worth looking at the model hydraulic systems available.

Next on the same subject – the folding wings articulate just like mi finger. How about thin wire cable 'tendons' and two big 'muscle' cylinders, hydraulic or pneumatic.

More food for thought, if you do consider pneumatics an excellent source for a high pressure pump is a Loyds Pharmacy blood pressure tester. They are only about £14. They run on nominally 6 volts. Pull one apart and you have no end of goodies inside!

Paul T – Not really too sure what you're trying to calculate. Some Greek chap a long time ago pointed out that if they are fully submerged then their upthrust will not change with vertical displacement. Statically she'll list to port or starboard until the hull hits the water. I know that you know this so nough said. Your next set of coloured drawings are much better and I believe it could be game on. the hull is only out of the water when she's moving and you have the hydroplanes for control. That could well work particularly with all the mixer R/C systems available for model aircraft. Incidentally, I think the picture of Ghost static with her sponsons submerged and hull out of the water simply shows her sat on the beach with the tide coming in.

This job is actually really interesting. With all the talent, skill, expertise knowledge and lateral thinking on this forum something must come of it!

Len

[Trevor HollowayParticipant @trevorholloway99134]

Throwing a spanner in here :

If any hydroplanes are on the sponsons they would have to turn as the legs move to stay parallel with the water surface – reasonably easy in the full size crafe but vastly more difficult on a model. Possible with a parallelogram link or cable system though.

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