RE: T-28 upgrade for PK-T28
I have found that the Turnigy SK 35-48 900 kv is a perfect motor for the Parkzone warbirds. The only modification required is opening up the hole in the Cowl. I have religiously used this motor on the F4U Corsair and the T-28. The original PZ motor mount lines up with 2 of the Turnigy motor holes on the and to date that has held the motor in place without any problems with loosening or vibration.
That same motor has now been used in the PZ ME-109, but does require some small and simple modifications. The motor mounts fine to the original metal motor mount, once again using two screws Since this plane has a cowl with a larger prop adapter, i took a hacksaw and cut off ~2mm off the end of the prop adapter - the side that that attaches directly to the prop shaft and bumps up against the prop. This allows everything to work great and you can use the original cowl.
The 35-48 is a very strong motor with big bearings and a 5mm shaft (SK version). The 900kv gives much "improved" performance over the stock motor without sacraficing battery life. If you want higher top end speed, get the 1100kv version of the motor.
Hope this helps,
JC