hydrofoil power system?

[Jesse J]

I know its not FE, but the requirements are much more FE than scale...

So I modified one of Dad's abandoned projects and got out the brass and blow torch (over a decade ago). It has been sitting waiting for a six channel radio and a viable power system that would have enough power to get it up on the foils, have a reasonable top end for cruising, and also have reverse. first thought was air power; Gas (original idea, in pics) - out, messy and no reverse; huge outrunner, ok I have two 4S batteries I could run in series, but over $300 and still no reverse...

I did see a YouTube of a smaller model (mine is almost 3' long) where the guy ran a flex drive down to the back wing, keeping it submerged during "flight"... got me thinking. So now I ask you guys about motor/esc/prop ideas. Flex/wire drive is probably the ticket, but I am wondering what would be best set up for high load starts and fast running for staying up on the foils.

The project is totally my invention untested and I have no idea how it might react to the water. Front foils are independently adjustable (hopefully making banking turns possible) and the back is adjustable as well. My hope is to be able to "fly" it once it is up, thus the 6 channel radio: 1) throttle, 2) rudder, 3) up/down of back foil, 4) up/down front foils, 5/6) "ailerons" of front fins (probably a flap mixer type thing).

I have had no luck googling for similar projects and I imagine the extremely creative folks on this forum (e.g. Diegoboy, Dr. Jet, etc.) might have good ideas for this type of project.

Here are some pics of the drydocked project

Thanks for input.

[RandyatBBY]

I have played with hydro foils a little I actualy raced one of the proto types in Fl.. Allthough mine was prop in water and not a air driven. Most air Boats are a little slow side. I would prefer a simpler approach to start with and after you have some sucess try more advanced setups. I would set the boat up with a 2 channel radio with 1) throttle and 2) rudder or flaps or both.

Kind of fun stuff, good luck

[Diegoboy]

Those wings are brass?
You will definitely need some speed to get them to "fly"
I assume you scratch built them correct?
Let's start with the front wing...
I would move the front wing a bit more forward, I would extend the wings beyond the side of the hull, This will give it the ability turn.
I would also make the angle of the front wing greater. so that the center runs a bit deeper, and give it a total of 3 angles (one in the middle, and one at each end)
Also, try to make'em a bit longer in the profile of the wings (front & rear)

Rear wing...
I would also extend the rear wing beyond the sides of the hull too.
Make the rear wing flat across the middle, but angle up at each end. Be sure that the flat part of the rear wing is as deep as the two outer angles of the front wing.

If you need drawings to illustrate what I'm talking about, let me know!

[Jesse J]

I meant to specify that I am intending wet prop, have abandoned the air - right, Randy too slow and not enough thrust. You might have a point about starting simpler than full blown complicated!

Wings are brass and definitely scratch built. I took 3/8' ish airfoil shaped tubes and soldered brass sheeting over them. As of now, the front are two wings and the back one. I could make four more wings, two to add to the front and two to the back to make the extensions you suggest - you have a good point, will also add to stability... Two angles on the front, like the dual dihedral wings of the slope gliders, right?

Making them longer in the profile.... that means undoing them and adding more sheeting... you are getting me less encouraged as we go.

back wing as deep as outer angles of front wing meaning the second dihedral change, yes?

Drawings would be cool, but let me first post some more better pics with dimensions to help answer as many questions before hand.

Thanks for the input, I suspected you might be interested in this Diegoboy, and lo and behold you even have one you are starting,

I also noticed you haven't decided on power, maybe one or two Feigao 14XL - but then what kind of prop???

[Viking]

Hydrofoil

Hi;
I have been planning a hydrofoil for a while. I did some research and found some very interesting stuff. Have a look at this--http://www.histarmar.com.ar/InfGral/Hidroalas/The%20Up-Right%20Hydrofoil%20Kits.htm
You might find this interesting too--http://web.mit.edu/2.972/www/reports/hydrofoil/hydrofoil.html.
The Germans did hydrofoils in the 1940s how hard could it be??????
You can use a single prop and tweek the rear foil to counter prop toque roll.
Of course counter rotating twin props would be really nice.
And just to tweek you a little check out this Japanese guy and his jet drive hyddrofoil
http://www.youtube.com/watch?v=wObflyTPLvM -- on Youtube
Good luck;
Viking

[Simon.O.]

I am amazed that a quick Google netted you nothing.
Don't despair as there are many brains here full of information that will help, mine may or may not be one of them.
I have done a LOT of reading on foils and various other hull forms in my quest to find a hull that will one day overtake and replace the conventional rigger. That is a LONG way off for me but Rembrand over on rrr is onto something at the moment.


There are a few foil runners here on RCG

http://www.rcgroups.com/boats-54/

Have a look around and see what is there.

I will get you some more links as soon as I get back to work in 2 days.

Always keen to help with the non conventional hull forms.

[Jesse J]

Thanks for the great links I have not spent extensive time googling, but I have found interesting stuff from modded models with fixed wings to full sized Bayliner (you gotta see that, pretty cool: http://www.youtube.com/watch?v=w54-O...eature=related ). But have not found many similar builds.

Here is some more precise documentation of my hydrofoil.

[Jesse J]

and then the stern.

I just remembered that for the wings I used that small airfoil shaped tubing (3/8" in diameter) and 2" sheeting. I bent the sheeting about in half back onto itself, opened it up just enough to insert the tubing and soldered it closed, adding a bit of some more airfoil. Totally brain-borne. Note, first thing when I get to the doing part is to glass the entire hull, so don't think all the cracks will even know they were there.

I started this just after graduating in geological engineering (obviously drawing on the engineering part) when I had a bunch of free time. I am now working on my doctorate and don't have much time to spare now, but for this project I think some well thought out planning is in store.

I think I can add Diegoboys extra wing tips fairly easily, as well as move the front wings forward, if necessary (why do you say move them forward?). I have noticed many real boats have them way up front, don't know why...

I could probably use two motors, but then twice the everything! Better to start with one beefyboy and work from there.

On that note, propeller... Probably not a surface penetrating guy. Maybe one of those three blade low pitch jobbies. Have toyed with jet, but then again water intake positioning and drag...

Any comments on propulsion?

[RandyatBBY]

Any comments on propulsion?

How big is the hull and the weight?

[Jesse J]

looks like 32" by 9.5" and weight... uh.... lets shoot for less that 6lbs. I am thinking 4S2P and whatever the motor - should be in that ballpark. Pretty flat hull, but drag from wings at first coupled with hull before launch will be challenge. should be pretty low drag after it is airborn.

[Jesse J]

Danny, it's this one... Same exact point, unless the movers have banged it up any.
I don't forsee me moving forward on this before the end of the year. I had toted with a twin setup... I also would like reverse, but may have to choose my battles.

[Diegoboy]

I remember this...
We may need to talk on the phone for this. PM on the way