Hello Fellow Modelers. I'm experiencing a little trouble setting up an ARF Christen Eagle from Hangar 9 to fly right.
I'm already an experienced builder and a decent pilot and I started working on this model a while ago.
Despite my effort to follow the directions included with the kit I found a certain dissonance between my personal impression of the design of this plane with the numerous reviews selling this model as an excellent flyer, smooth, round capable of very soft landings.
The bird frankly behaves aerodynamically like a musk covered boulder. It has the tendency to change direction jerking left and right, and has no stability on the rolling or pitch axis. It is very difficult to land and has the tendency to pick down and loose lift especially during landing.
I thought it might be related to weight balance first and then I blamed on the motor's thrust angles.
Despite playing for a long time with these, the initial, stock setup seemed to be the best (the least problematic) setup.
Then I swapped my nitro setup for an equivalent electric, lowering the all up weight, perfect CG, the worst flight characteristics.
Then I noticed something strange. The lower wing seems to have a neutral to slightly positive thrust angle, which I found normal.
The upper wing though seems to have a neutral to slightly negative thrust angle and I don't think this sounds right.
I have the impression that I was simply unlucky and I got a defective plane with mismatching thrust rods and wings not sitting right.
I looked on several build plans for this model noticing the most different thrust angles. On the Pilot plan the upper wing is set at +1 degree, which sounds reasonable enough and the low wing has a neutral 0 degrees thrust. On another plan published on a magazine from some years ago though the wings are thrusted in the inverse way, with a neutral thrust angle on the top wing and a 0.5 degree at the bottom (weird?). The plans are consistent on the motor thrust angles (0 down, 1.5 side ), ok. So I decided to do some research to find out what the original thrust angles from the original Christen Industries plans are with no success. HAs anyone built a similar model or have any idea what the correct thrust angles should look like on this thing?
Thank you for understanding.