Pepsi Chipmunk Build

Pepsi had her maiden on Saturday 19th February. Jon put her through the paces as usual.. Needed a fair bit of trimming though. Quite a lot in my humble opinion.

Trim comparisons in clicks (JR radio 1 click = 4 steps) with Pennzoil Chipmunk below. With Pepsi now back home and looking at the ailerons they do look odd for level flight and the elevator a very obvious down.

Aileron: Pennzoil = 28 Right Pepsi = 48 Right
Elevator: Pennzoil = 24 Up Pepsi = 52 Down
Rudder: Pennzoil = 24 Right Pepsi = 24 Right

I can live with Pennzoil, but how to I go about or what to adjust to reducing the trims on Pepsi?

The more I look into setting a plane to reduce excessive trim the more it becomes a wider subject. :blink: Spent the afternoon reading about setting up planes. Brain overload! so, back to Pepsi.

Reading the TX trim settings for Pepsi. Elevator down trim. Plane wants to climb even at cruise throttle? Engine thrust line? Main wing incidence? With the latter I assume the centre line of the main wing should be parallel with stabiliser and or the centre datum line of the fuselage?

Ailerons, one is quite a way down the other slightly up. Not sure which way to go on this one?

I suppose the first step with regards to the elevator down issue (I assume this is because the plane wants climb) is change the engine thrust line, ie; more down thrust. The firewall supposedly has built thrust angles but my hand cut metal mounts may be very slightly not exactly equal in length which could be the problem, don't know.

Or for a sport plane am I being over-concerned and being too picky?

Repainting the Cowl. With some time to spare and the willingness to make an effort I stripped off the cowl's RC Colors so called Oracover matching blue using acetone. Then etch primed in grey. After a light 800 wet-n-dry then sprayed the cowl with 3 coats of Fiat Capri Blue. After 48 hrs I did two light coats of lacquer (petrol resistant) normally used for motorbike tanks. Allowed this too harden. now here comes the fun bit - applying the expensive transfers. It was even more fun than the last time, the lacquer is so resistant it did not want the transfer's adhesive to stick very well too! However, with some extended effort I got the transfers down and then sealed them with vinyl seal.

At least this blue is nearer the plane's covering! Compare with last image!