Stopping torque roll

[ezhitz]

My son tested his Osborn Miss Supertest running 7XL on 4S spinning
an X442 the torque roll was so bad the boat would just slap the left sponson and
flip as soon as you give any throttle.My question is should he try going with less pitch or smaller dia. or both? Tried a proboat 1.6x2.5 composite that lasted about
4 feet until it sheared off both blades.Thanks

[Jesse J]

yep, try smaller/less pitch. Also you can load up the port side to try to counter act it. I know its frustrating, but you will find a solution, it just may take a little work.

[Rumdog]

What size is that hull?

[ezhitz]

thanks guys
the hull is 31" with a 12" beam.The batteries are under the front deck and the sponsons are
sealed so what I was thinking was to drill the back of the left sponson and put in a tube that
could be sealed off that weight could be added a little at a time.First he can try a 1440 or maybe grimracer 40 x 53.

[Jesse J]

I would also check to make super sure your turn fin is dead straight. I have had them do funky things to performance. That's an awful big hull to be feeling torque roll... I am suspecting something other than prop at this point.

[ezhitz]

thanks Jesse did try with out the turn fin was about the same.
heres a quick clip

http://http://www.youtube.com/watch?v=HXrcSr-UrCo

[Rumdog]

How deep is the strut? I'm betting it's way too deep.

[Flyguy55]

First thing to cause torque roll is a dull prop. You need a razor sharp prop.
Composites just are not ever sharp enough. Think about cutting meat with a table knife compared to a very sharp finely made cutlery. Water has resistance.

I think 7XL is too hot a motor for 4S . An 8XL or 9XL would be a better choice. KV is 2340 RPM Per Volt . Your pulling way too many amps for a sport setup with a
X442 . It may be a good thing your having proplems , otherwise you'd be burning something up.
I think the sheared blades are telling you this .

You might try something in 35 - 38 mm dia . The the smallest first .It will be better , if it will get on plane .

Better bet would be a 9XL .

Even better would be a P limited set up.

I race a 10th scale Bardal , 36" long on a BJ motor KV around 1800 , CC 80 ESC , and 4S- 5000s.
The boat blows over if I dont pedal it . It was plenty of power .

[ezhitz]

Thanks Flyguy55 i have 9XL for my balsa cat I will try in his boat
this saturday.The strut is set to the same depth as the sponsons.
I guess the worst fears would be if the hull is twisted.

[Flyguy55]

Start easy on the throttle , and be sure the prop sharp. It should be fun . I'd still start with a x440 to start .

[ezhitz]

thanks i will tell him to get x440 and x438 won't hurt to try either.

[ezhitz]

Had the boat out today running a 4s pack on the left side plus some weight
attached to the left sponson still a hand full.Running a 1440 prop.http://www.youtube.com/watch?v=onGtlSwZXDg

[andym]

When guys are saying a sharp prop I find a lot of people do the edges ok but where the blad leaves the hub has to be just as sharp, if it is blunt there you will have trouble.

[JimClark]

How bout too much power for that size boat

[ezhitz]

Thanks Jim I keep telling my son that but what does the old man know lol.
I wanted to try a 9xl I had but it went up in smoke today it was in my cat that i had the
esc burnt up so when we put in this boat to try it sounded like the motor shaft spun and started to smoke.I think this boat kit was originally designed to run a 700 cordite motor ?