Flying yachts

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19 July 2016 at 09:52 #66628
Bob Abell 2
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@bobabell2
Take a look at these yachts, chaps……….They are actually……..airborne!

Could a model do this?

The next secret venture for Ashley?………Or am I raining on his parade?

It seems that the lift comes from the hull shape

Bob
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19 July 2016 at 09:52 #9489
Bob Abell 2
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@bobabell2
Something new
19 July 2016 at 10:46 #66629
Dodgy Geezer 1
Participant
@dodgygeezer1
They are hydrofoils. The lift comes from wings mounted on the keel, rudders or other dagger plates.

Model hydrofoils were certainly being built in the 1960s – there may be stability issues with yachts, but I suspect that modern technology could address these…

Edited By Dodgy Geezer on 19/07/2016 10:47:35
19 July 2016 at 10:50 #66630
Kev.W
Participant
@kev-w
Amazing design. **LINK**
19 July 2016 at 11:02 #66631
Bob Abell 2
Participant
@bobabell2
Thanks chaps

All very interesting

What will the Boffin's think of next?

Bob
19 July 2016 at 13:33 #66637
Dodgy Geezer 1
Participant
@dodgygeezer1
Here's a model one: **LINK**

You can see that stability is still a bit of a problem… but they're getting there…

Edited By Dodgy Geezer on 19/07/2016 13:35:20
19 July 2016 at 15:02 #66639
Paul T
Participant
@pault84577
Hello Captain

A couple of years ago I played around with a similar fin mounted hydrofoil design for a twin hull speedboat. I had intended to fire up your interest in building the super fast monster but I became sidetracked into designing the hulls to tilt during high speed turns.

You might recall our discussing the 'Banshee' project at Haydock. We carried on the conversation over the interweb and looked at various existing spaceage designs.

Unfortunately the project never got to the prototype stage and is still languishing on the drawing board.

Paul
19 July 2016 at 15:15 #66642
Bob Abell 2
Participant
@bobabell2
Thank you, DG

The model did very well, although a bit chaotic at times

It seems a great idea but not very practical and yet some one thought it a good idea, having built the full size versions?

Paul

I remember talking about it

Wonder what became of the Invisible Man, as he was involved too

Bob
19 July 2016 at 17:33 #66645
Dodgy Geezer 1
Participant
@dodgygeezer1
It's easy enough to do for power boats, and there are some old hydrofoil plans around from the 1960s of this type.

But yachts are a bit more tricky, with rapidly varying sideways forces. A wide-based multi-hull seems to be a basic requirement. But I would not be surprised to find that helicopter gyros allied to fast servos altering the submerged wings could get a thin hull out of the water while remaining stable. Bit like fly-by-wire…
19 July 2016 at 18:13 #66646
Bob Abell 2
Participant
@bobabell2
Thank you, DG

I was thinking along the lines of those Skegway thingies, for balance control

But they would need calm waters?………Or could a PC take care of such inconveniences?

Bob
19 July 2016 at 19:45 #66647
Gareth Jones
Participant
@garethjones79649
I think an Arduino could probably cope if it had the right sensors and actuators…… steps back after lighting blue touchpaper.

Gareth
20 July 2016 at 08:51 #66651
Dodgy Geezer 1
Participant
@dodgygeezer1
Posted by Bob Abell on 19/07/2016 18:13:38:

Thank you, DG

I was thinking along the lines of those Skegway thingies, for balance control

But they would need calm waters?………Or could a PC take care of such inconveniences?

Bob

Things are stable when the force pushing something out of balance is less than the natural restoring force of the system. If the natural restoring force is large compared to the disturbing force, the system is stable, but sluggish to respond. if the forces are more equal, the system is agile, and if the disturbing force is greater than the restoring force the system is unstable.

An unstable system requires constant control inputs to keep it in a desired state, and this was impractical for most systems until rapid computer control became possible and cheap. Nowadays we often have Electronic Stability Control in our cars – so that if the car moves into a situation where the normal restoring forces are diminished – water or ice on the road, for instance, the car can still be controlled.

Stability design means having an appreciation of the size and rapidity of control feedbacks in a system, and is usually heavily mathematical. In the modelling world, we often short-circuit the maths by designing things that 'look and feel' right, based on extensive experience. However, as you can see from the youtube clips, we are only just starting to gather the experience necessary to build stable foil yachts, and so anyone working in this field would be well advised to have at least a basic knowledge of stability theory. It may be that clever design can avoid the need for computer assisted feedback altogether, but I note that (the few) youtube yacht foils I have seen have all had servo connections to the foils… **LINK**

Incidentally, I don't think a colour-coordinated dress is an essential part of the design…

Edited By Dodgy Geezer on 20/07/2016 08:52:20
20 July 2016 at 16:42 #66656
ashley needham
Participant
@ashleyneedham69188
Nah, It would never work as a model….. (that's my expert view of course)
Like Pauls idea of a tilting hull or hulls, now there's something to play with

DG surely you colour coordinate when you are boating???? essential at Bushy Park.

Ashley
20 July 2016 at 17:34 #66657
Dodgy Geezer 1
Participant
@dodgygeezer1
DG surely you colour coordinate when you are boating???? essential at Bushy Park.

Alas, I don't look that good – and neither do my models….
20 July 2016 at 19:14 #66659
Paul T
Participant
@pault84577
Ash

The underwater shape and the mechanics of the tilting hulls gave me a few headaches, most theoretical profiles worked fine at low speed but they all fell apart when the speed went above 17m/s……finally cracked it though with a very odd underwater profile.

Like you said its something to play with

Paul
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