View Full Version : increasing prop size?

03-14-2011, 01:08 PM
Just curious if you guys prop up when you at weight to your boat? Reason I'm asking, I built a 1/12 scale 26" shovel nose hydro that runs great on 3 cells and a 440 prop. ESC and motor are cool to the touch when I bring it in. But when I put in the 4 cell pack it seems like there's not enough prop to get it on a good plane and get the back out of the water. I'm using the same point on the hull for my CG.

36-74 2075kv (8XL)
80 amp esc
3cell 4400ma- runs great
4cell 4000ma- won't plane

Any thoughts and help would be great.



Flying Scotsman
03-14-2011, 01:41 PM
You are almost overpropped already, but 3S is great power for that size hull and your motor choice is dubious, an L sized motor might be a better
choice...my 2 cents


03-14-2011, 01:56 PM
Your motor choice is good for 4S power although a bit heavy, and the x440 is not too much prop as long as your cells can handle the draw. It may be a case of applying too much throttle at first until a plane is reached. If the CG is actually in the same place and the strut has not moved, the I'd go with at least an x442 and see if that helps, otherwise try being more gentle on the throttle at the start.

My club runs an N-2 class with hydros the same size as yours, and we run a 7L motor with 2S. I add about six ounces to the boat to keep it on the water and the x440 prop is plenty for the hull.


03-14-2011, 02:10 PM
Thanks for the input, this is my first FE build. I got tired of messing with nitro and sold all of it. The 8XL is big for the hull and I think the weight of a 4S set up might be to. I think I'll look into a "L" sized motor in the 2500kv range so I can keep running my 3S packs.