JUGFLIER

I have a Carden 35% edge I just finished. Problem: Under full or near full throttle, the airplane pulls to the belly and wants to dive downward. When you pull of the throttle, it flies true and straight.. My first conclusion is that the engine has down incidence. So I put a washer under the bottom mount, and flew it and it helped. I added another washer, now the engine clearly has upthrust. With the second washer, the problem is actually a little worse. I'm beginning to believe the engine neds to be lowered on the firewall. Any suggestions from any experienced builders?

I did get an incedence meter and wings and elevators are perfect.

mrbigg

My Feedback: (21)

Strange. Mine is set at 0 degrees with a little bit of down and flies perfect. Sure you don't have any throttle to elevator mix?

zx32tt

My Feedback: (9)

Unless you are using large washers, sometimes call "fender washers", they may be compressing the firewall and offering only a temporary fix. Use your incedence meter on the engine's prop hub to check how much you are actually changing the incedence of the thrust line. Be sure your cg is correct 1st before trimming for upthrust. If you mounted the centerline of the engine according to the plans, you should be good.
zx32tt

Lnewqban

More change respect to the CG is achieved with thrust angle than with relocation on the firewall.

Your incidence meter can be used for verifying the real thrust angle:

http://www.robart.com/sites/default/...w_To_Meter.pdf

nitro wing

My Feedback: (1)

Also recheck the firewall to make sure it is not moving under heavy loads.
I have had a similar problem with trim, and it was a loosening linkage in the elevators..which gave odd trim changes under various loads.

As mentioned test all deflections to make sure you did not end up with a weird unwanted mix on the radio. This can happen easily.

speedracerntrixie

My Feedback: (29)

I would look at CG and elevator trim first. Reason being is that is you are tail heavy you will be trimming in some down and it becomes more effective at higher speeds. As faas incedence goes, set it up with zero down or up thrust, zero stab and 3/32" positive measured at the trailing edge.