I have been striping the rx gear out of my spare p51 pst to put in my sig kadet. Here is the question all my servos execpt for 1 is a JR 537 the other one is a Jr 517, Would it be ok to use the 517 on the trottel and the 537s on the control surfaces? Is there any down side?

Perfectly OK, no downside that I can think of.

No problems at all.

Ken

why are you writting in here go fly lol just kiddin no problem must of us have mixed servos

HI!
You can use whatever servos you like...JR, Futaba, Hitec, Multiplex, Sanwa doesn't matter.
Regards!
Jan K
Sweden

Just make sure that if you use dual aileron servos--they are the same kind.

Don't use a JR 517 on the left wing and a Hitec 425 on the right wing.

As long as your only using 1 servo per control surface--use whatever ya got in the shop.