Anyone know what exactly causes this? I have heard the air in front of the prop starts vortexing, so you lose your pull. Heres my dilema, I have a Katana GS 40 profile with a Saito 56 swinging an apc 13x4/sullivan spinner nut. On calm days when I get in a hover the prop will get loud and wash out. I can power up to overcome this but it makes me nervous when low to the ground.

I really like the plane/engine combo but I also have an OS 70 as well.
My guess is the only fix is to go to a larger motor and prop. Any other suggestions? Thanks for an help.

Super...you might just experiment with some different props. Seems like the easiest solution anyway, as your plane seems to have enough power to hover and then punch out. More power isn't going to fix what's ailing you.

A finer pitch will resist the separation bubbles that it sounds like you're experiencing. The noise and loss of lift is consistent with the blade airfoil stalling over part or most of the blade. What prop are you running now?

13x4 apc, I havent tried a 12x4W. I think a 13x4W may be too much for my Saito 56.

Vortex ring formation has been the official blame of V-22 crashes I hear. Here is a link that describes the phenomenon.

http://www.dynamicflight.com/aerodyn...ettling_power/