xmtner

I recently mounted Great Planes glass floats on a Great Planes J-3 40 size ARF. The center of gravity is way off- needs 11.5 ounces. I then mounted the wire gear opposite of what is shown in the instructions ( high end in front, low end in rear) and the plane balances fine. I seem to recall seeing a post from someone saying the pictures in the instructions were wrong.

Anyone else have this problem? If I leave the floats as mounted, will my angle of incidence be to great? Thanks.

seaplane

A good way to check your angle of attack is to mount a yard stick or similar device under your flat bottom wing above a float. Check the distance from the stick to the float at each end. The front should be a little larger than the back. With the yard stick, a 1" difference will give you a 1.6 degree angle, 2" equals 3.2 degrees, and 3" equals 4.7 degrees. I wouldn't go larger than a 3 degree angle to start with....Seaplane

seaplane

A little more info on the yard stick meathod. For every degree of incidence use 5/8" . Two degrees = 10/8" or 1 1/4", three degrees = 15/8" or 1 7/8", etc..... hope this helps. Seaplane

jrf

My Feedback: (551)

Where is the step in relation to the CG of the airplane? If your balance weight changed that much, turning the struts around must have moved the floats forward or back as well as changing the incidence. The step should be directly below or within 1/2" of the Airplanes recommended CG.

Jim

4*60

My Feedback: (41)

Where were you planning to put the weight?? My understanding and limited experience is that when going to floats from wheels, weight is needed at the front to balance. What I recently did is drilled some holes at the front top of the floats and added shot and epoxy to the holes. Then filled and refinished the area. You normally add the weight to the floats so that when you go back to wheels your CG is correct and vice versa.
With the front of the floats further out than the prop, you can also add a little less weight than if you added it to the fuse.

"That's just my opinion. I could be wrong., of course!" - Dennis Miller.