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[RipSlider]

Hello all.

My PCF is nearing that wonderful point where all the sub components go together and a proper looking boat magically appears. Then paintng and weathering and then done. I think I have about 50-70 hours of work left to do on it.

So I've been having half a ponder about what I'm going to do next.

One of the idea's I had was to do a hydrofoil - but having had a scan about there doesn't seem to be much available in the form of kits or plans.

Traplet have a plan, but it is not very scale. There is also a kit from the 80's available but Barry at Westbourne has warned me away from it, so I will stay clear - as he seems to know his stuff.

So I was wondering if anyone else has every produced kits or plans for a hydrofoil?

If anyone knows of one, I would be greatful for details.

Steve

[jules64]

Steve

Model Boats Jan 95, has a construction article and plans for a Free lance semi scale customs type launch. Designed by Graham Goodchild and called the Highryder. More of a functional than scale hydrofoil.

Classic fast ferries has lots of picks of hydrofoils etc, but no plans.

http://www.classicfastferries.com/

International Hydrofoil Society has wealh of info, but very few useable plans.

http://www.foils.org/
http://www.foils.org/modelrc.htm

Graham Taylor , I believe used to sell a plan for the Rapier, but his website apears to be down.
http://www.home-taylor.freeserve.co.uk/

You mention the 80s kit, can you advise which one this is and who may have one available?

Best wishes
Jules64

[Tester]

Steve

I have a copy of the Jan 95 plan and build article if your interested.

Richard

[d-jnana]

Hi Richard,
Gary here (d-jnana) sorry to butt in on your string/reply/thingy, but this plan looks just the thing for one of my GCSE engineering students. How much would you want for a copy of the plans and article?


GARY

[RipSlider]

Same for me!

Do Model Boats have a plans service/re-issue service like MMI do? If so I will go through them as it will save photocopying etc.

Steve

[Tester]

Steve

I'm happy to send you plans and article for a small donation to the forum.

Can you and Gary work out how to copy etc as I am away on business soon so will not be able to do any copies as the plan is a bit to big to scan

Richard

[RipSlider]

Hello all.

I'm kind of playing with the idea of a hydrofoil for my next project - they seem to be pretty interesting in that there is lots of scope to play with control systems, fiddling with gyros and mixers etc. ( and the "boat" bit seems relatively easy to build to be honest ).

The problem rattling around the empty space that is my skull is that I can't see a curring mechanism to build the actual "foil" shape of the hydrofoil itself.

Not having access to a milling machine or CNC device it does not seem to be the easiest task. One cunning plan that seems to suggest itself would be to mould it as a flat bar strip ( fairly comfortable with doing this - I think ) and then bend it up into shape afterwards.

Another would be to get a flat bar into the right shape, body filler it ( or something similar - maybe that foam metal/epoxy stuff that I've always wanted to play with ) and then sand to shape. This also seems do-able, but a pain in the funderment to do, and I'm not sure it'll actually survive very well.

However, neither of these seem especially cunning or clever.

Does anyone have an idea that could actually be called "sensible"?

steve

[Eddy Matthews]

Does anyone have an idea that could actually be called "sensible"?

steve

My suggestion would be to stop looking at it in such a complicated way - No offence intended!!

A simple FLAT foil will work, just look at a simple "chuck glider" to see that a flat wing WILL keep an aircraft in the air as long as the angle of attack is correct. Okay, we all know that an airofoil section will work better, but at model sizes the difference is marginal, and as a boat is running in water which is vastly more dense than air it should matter even less - Apart from drag....

Most of the semi-scale and none-scale hydrofoils that are around just use a simple flat foil made from aluminium sheet....

Regards
Eddy

[bigford]

hey rip

 http://www.foils.org/gallery/index.htm   

[RipSlider]

I did think about that, but the thing I like about the idea of building  hydrofoil is that they have a whole load of dynamic elements in them which is the interesting bit.

If I'm reading the grraphs and papers on foils.org correctly, I reckon that a flat foil needs an extra 5 kts to get it onto the plane, and it knocks the sea-keeping around fairly badly as well. The key difference is that a flat winged plane probably have a very low wing loading, where as a hydro foil is going to have a very heavy loading - which means that the b oat is going to have to be fair belting along before it planes properly.

If I do have a crack at building a hydrofoil I probably won't mind how it looks - in fact it's probably going to look pretty damn ugly, but I would like to put all the technical bits in. And so I may as well have a crack at doing a proper foil if I can as well.

I totally accept it probably isn't strictly nessacery to build a proper foil shape, but then again, we have a hobby where we spend hours adding tiny details purely becuase we want to.

Steve

[Eddy Matthews]

I'm glad you didn't take offence Steve,

I can see where your coming from, so I understand your comments.  Although I've never built one, I'll be interested to follow your progress. I do have a PT50 hydrofoil form the old 70's-80's kit that was produced, and it does work well once the foils are positioned correctly, though careful setup is required! The kit uses simple flat foils, which I agree may not be ideal, but they DO work!

Regards
Eddy

[SteamboatPhil]

Steve
If you are going to build up a foil, don't use flat bar and build on that, as you will produce quite a heavy lump that will be hanging underneath the hull, and need a lot of power to lift it---if indeed it will lift. I would use about 16th ali, rivet on the struts, bond balsa layers to the ali, shape and then a light cover or glass resin. This should give you your shape and be light weight.
Hope it helps
Phil

[RipSlider]

I *knew* there must be a clever way of doing it!

Would you get get the flat foil into shape first, and then add the balsa - which seems tricky to be honest - or would you build it all up flat, and then bend it to shape - which would be preferable as it seems an easier way to produce a standard shaped foil, but would need the balsa to be steamed and a very careful choice of glue - if in fact it's do-able.

Or would you bend the bar into shape, and then produce a long section of foil in balsa, and then steam it and then glue on? This seems the most practical, but free-handing a long length of balsa into a consistent foil shape would seem to be a bit tricky.

Steve

[SteamboatPhil]

I would bend the ali foil first, then use thin balsa and laminate it, there for you would not need to steam the balsa.

[d-jnana]

Hi Richard (TESTER),
I,m happy to copy the plans for people (full size, we have a great copy shop at home in Swansea) for cost plus cost of post. That of course is if you are willing to part with them for a few days, and trust them to a) the postal service, and b) some one you've never met ie me. If you can the best thing (rather than clog up this string) is to P.M. me.

GARY

[RipSlider]

I've ordered a set along with the build article.

As soon as they come I'd be happy to dish them out to anyone interested.

Steve

[boatmadman]

I would like a copy please.

Ian

[RipSlider]

Is it easier if I lodge them with Martin or one of the Admins - then anyone on the site who wants a set can get them for a small donation to MBM?

Steve

[Tester]

Steve

I have sent the plans and build article to Gary as I assume from your post you have ordered via MB service. He may be able to copy plans and article for those who want it.

Richard

[Umi_Ryuzuki]

Lf you are using a propeller, there should be no problem getting the speed you require to use a flat foil.
If you are using a fixed "V" foil, then there should be few issues getting it tuned and set to fly.

That's where I should have started... ::)


There are alot of issues running the submerged foil type. The inverted "T" are inherently unstable, and
require that a gyro and aerilons be installed. There is also the issue of the front foil diving, Although
Yoichi Takahashi seems to have overcome that issue without any trouble. (on no less than three models)  ???

Also, most submerged foil types are jet pump. a standard jet pump needs oversized struts to  move the
volume of water up to the boat. Even then enough thrust is not guaranteed. I tried a Graupner Mini Jet, and
it had great thrust, but not enough to over come the drag of the submerged foils.
I'm still working on that.

However you can Cheat, and run a long fixed, or flex shaft down beneath your stern foil and get plenty of
thrust for submerged foils. Then just play with the tuning. 

Aimee

foils out of GRP and aluminum...

[Big Ada]

Has anyone fitted foils to a Springer yet ?

Len.  ::)

[Umi_Ryuzuki]

Has anyone fitted foils to a Springer yet ?

Len.  ::)

Yeah, Toesupwa already did that to "Scoot"

 

[kno3]

Huh, why would a tug need hydrofoils, is it THAT fast???