hello

i have a great planes extra300 40 size with an o.s 46 fx.
it doesn't have enough power.

i have seen the gms76 in a good price.
i don't have expirience with those engines.

do you think it's a good combination?

thank you
roy

The .76 will be too heavy. It will be nose heavy and you will have to add even more weight to get it to balance properly. This will made the plane snappy and you will have to land faster.

OS 46FX 16.45oz w/Muff.
GMS 76 21.9oz w/Muff.

The GP Extra 300 .40 was designed to be a scale/sport/aerobat. The kit was designed a few years ago when no one had heard of 3D and very few attempted to hover.

If you want more power you can get a OS 50SX (better) or a Saito .72 (best choice) as both are less than 17oz ready to fly.

If you built it stock, then you won't get much 3D out of it as the rudder and elevator are not powerful enough. The thin ailerons don't help either.

I have a Saito 72 in mine and it goes very well, but plan on putting a Saito 91 in it instead to give it unlimited vertical. I fly it for general/IMAC aerobatics as it does these very well and smoothly for a 40 size plane.

What weight is yours? Mine came out at 6lb (2.6kg) with the Saito 72. If yours it significantly lighter, then go with the Saito 72, otherwise consider the 91 like me.

If you wish to stay 2stroke, then you have the problem that all the 60 size engines weigh a lot more than the 40 size engines.

yes i see the problem of putting a 60 in a 40 size plane.

i would like to stay with a 2 stroke engine.

i think i will stay with the 46fx and that's it.

thank you for your help
roy