cg on mono

[ChoppyOne]

I built an old prather aggressor II (41" x 10.5") first build I set the CG up at 28% (11.5") from back. The boat moves good in the water except in cornering ! its like it rocks back and forth from front to rear sometimes rear lifting out of the water very unstable in corners. any suggestions ? Help? im running a 40x92 1730kv Leo with a prather 245 prop I tryed a 647x3 oct it calmed down some yet still unstable .

Thanks in advance

Dave

[lenny]

Did you try tucking the rudder a little ?
And can you post some pictures up of the boat hardware and the setup in the hull ?

[ChoppyOne]

securedownload.jpgshe devil.jpgHeres some shots Lenny........I read on OSE about rudders causing this is it too deep? to high? like i said first build
Thanks in advance
Dave

[lenny]

By tucking the rudder,
I mean for the bottom edge of the rudder to angle towards the transom just a little bit.
It sounds like it is plowing to me in the turns and running wet.
The stinger looks low to me,
I would raise it so it is level with the bottom of the hull.
Use a straight edge a cross it.
Also tabs at level to, With a straight from the bottom of hull to back tips of tabs.
Show us some pictures of the in side setup with the cells in place please.

[785boats]

Choppy.
I would say that there is not enough rudder in the water.
The rule of thumb I like to use is, at least the diameter of the prop hanging below the bottom blade of the prop. It also looks as if the top water intake is level with the bottom of the prop hub. There's a good chance it will be picking up more air than water and not cooling things very well.

The turn fin is possibly a bit high too. The tip is well above the waterline when running level so there is room to drop it a bit or put a larger fin on the existing bracket. There isn't enough in the water when the boat turns. That also adds to the bad handling characteristics in the turns.

Just my thoughts.
Paul.

[lenny]

Good points you have there too.

[ChoppyOne]

ill try that had to adjust positive angle too keep the front down and also think im twisting to large of a prop (prather 245) as my batteries are swelling. ill shot some of the inside and post here in a min.
thanks
Dave

[ChoppyOne]

Thanks I will try that, I did notice both water outlets were spraying water but i can drop the rudder and try.

Thanks again
Dave

[1truckerdan]

ChoppyOne here is a link to a site that I learned alot from

http://www.modelpowerboat.com/content.php?118-rc-boat-hull-attitude

[ChoppyOne]

ChoppyOne here is a link to a site that I learned alot from

http://www.modelpowerboat.com/conten...-hull-attitude

Thanks im on the way over..........Dave

[1truckerdan]

@ ChoppyOne,
I hope that link helped you figure it out.
Daniel

[ChoppyOne]

real good info Thanks , I do have one ? the further back you set a rudder it does what ?