sr243 wrote:yea my CG is with propeller and rubber band included. I really don't want to build a wing and it is going to take too long since regionals are within a week and i don't have time for this event (not even mine). My last resort is to wind the rubber band up with half the length so it will last like 15 seconds but it will stay up in the air. I think some people had planes without curved wings that worked.
It sounds like either a) your wing doesn't have enough positive angle of incidence or b) your horizontal stabilizer has too much positive angle of incidence -- or both. The angles of incidence here is relative to the propeller thrust line, which depending on how you built your plane, may or may not be in line with your motorstick. As a starting point, you want the wing to have approximately 1 degree of positive incidence and the horizontal stabilizer to have 1 degree of negative incidence.
I also noticed in a previous post that you said your rubber motor was 70 cm long. I assume you mean that the total rubber used is 70 cm, so that the rubber motor, when tied in a loop, has a length of 35 cm. I also noticed that you mentioned shortening your propeller to 13 cm. Be sure that:
- your motor weighs less than 1.5 g
- your propeller is 20 cm