Paul,

Thanks for your input, this will do,
A receiver will be 100 grams I think, especially a (Medco!) reeds relais is heavy I think.
and a 5 cell battery about 120 gram.
Your weight of the servo is more important to know, because there were 5 of them in the plane.
Total weight of the radio equipment is about 650 gram, nearly unbelievable with that 0.45 K & B.

Thanks Cees