Rowboat

Out of all the RC Airboat hulls that I have seen I have not seen a working Canard style boat before. So I built one out of some old hulls that I had lying around. The basic idea works but I am having trouble with the turns. This is the first boat that fights me in the corners. She just wants to run straight. But she has a lot of potential for a fast boat. This vid shows me driving and videoing at the same time. So the driving is a bit slow. The boat is powered by a OS .55 engine with a 11x6 prop.
[youtube]http://www.youtube.com/watch?v=OdtJ9rYVIV4[/youtube]

stackeddeck

That's really awesome. Sorry I can't help.

crispyspa

Hmmmm....I see the dipping of the sponsons and I tried to pause the video to see the shape of the bottom of the sponsons but I couldn't see them that well. It looks as though (from the side) that the sponsons aren't flat. Do they taper from front to middle then flatten out at the stern or is it a full taper from front to rear? how wide are the sponsons?

Either way, there is enough displacement to get on plane, just not enough to hold the extra weight of the boat during a turn.



Does it do the same thing at higher speeds?

Rowboat

They taper from front to just before the stern then it steps up and tapers out to the stern. When turning At high speeds the sponsons seem to dig in and that causes the boat to loose speed making the turns very slow.

This is a pic that shows the sponsons.

pinky_d_brain

Move the sponsons out farther this will lessen the force from the boat wanting to roll over on a tern by giving the hull more leverage to act against it, like getting a longer wrench

Brandon4164

My Feedback: (1)

hmmm you invented a dragracing airboat Petty Cool nice job!

Bradh2000

Great job Rowboat ! Maybe if the rear sponsons had more of an angle on the side, they would lift more in the turns.

Rowboat

This is one option that I have.
I am also thinking of duel rudders, one on each sponson. Or a front rudder so the stern can slide around. Still more testing to do.

Hesco Racing

What rudder servo you using? It looked like at low speed she wants to turn but as soon as you put to much load on the servo she battles. What battery you using. Sometimes going to 6volt battery can help. Your canard and a tunnel boat has the same tendency. In our 3.5cc F1 tunnel boat we use a 13kg steering servo and sometimes still have to come off the throttle to turn sharp corners.

Cobus

And as a side note are you nuts riding your boat while you can hear the thunder in the air. You are standing with one of the best lightning rods in the world in your hand. I woudl be s)*tt(*g myself.

Rowboat

I was using a 4kg servo I have a 11kg servo that I will try.
I also want to try a shorter rudder, say a 75mm insted of the 120mm rudder that I am using.

As for the storm it was half an hour away and going away from me. I was standing under a bigger conducter our metal shed. Well I am still here.

Hesco Racing

OK you are off the hook.

The length of the rudder will only give you straight line stability. How wide is the rudder?

Cobus

Rowboat

it,s 20mm wide

Hesco Racing

That sounds a bit narrow. If you consider a 3.5 outboard leg's fin tapers from 35 to 20mm over 40mm length and you have the prop thrust still pushin. When I make rudders for from nitro to gas the minimum is 25mm at the bottom tapering to 40mm at the top.

Just my 2 cents.

Have any pictures of a side profile view of the boat?

Cobus

Nigel H

Hi
Very interested to see your Canard airboat. I originally considered that design but I opted for forward sponsons because the I felt there would be less tendency fof the boat to flip up. Have a look at my Airkom boat running on a local canal (powered by a Tower Hobbies .46). It likes straight running only!)
N


(apologies but I cannot get the clip in ANYformat.... AVI, MOV or WMV... to up load) Here is a picture of it slowing down after a reasonably fast run

Rowboat

Not yet maybe later. Try to get a pic of the side and rear.

Nigel H. That looks like a fast running boat. My boat is still in the testing stage. I still have some probs with the turns.

Hesco Racing

Any progress on the boat?

Cobus

Rowboat

I have lengthened th sponsons by 50mm. And I want to attach a larger turn fin to the front sponson.
I will be going for a test run next Sunday. Hope to post some vid then.

Rowboat

Ok I have tweeked the sponsons. Lifted the rudder, the boat ran a lot better.
But I still have trouble turning. So I shaved the corners on the sponsons with a hand planner to try to stop the sponsons from digging in when turning. Well It worked and worked well. Now I can turn without the boat comming of the plane.
In the first part of the vid you can see the boat bogging down in the turns , the second part the boat stays on the plane.


[youtube]http://www.youtube.com/watch?v=lmOC2L-PAqc[/youtube]

crispyspa

video isn't showing up.

Rowboat

For some reason the link does'nt work . I will try tomorrow to fix it.

Rowboat

Try the link now.