RE: False firewall
G'day. Yes that would be true if I were using a single cylinder engine and I have used those in the past and they work well.
But ...
I want to put a Saito Radial engine and they don't use a separate engine mount - they bolt directly to the firewall and the pattern for the R90R3 3 cyinder radial is not the same as the pattern for the 90TS (twin) and different again from the Great Planes adjustable mount.
To further complicate things, I want to make a removable nose for the plane that will fit a radial cowl and still be able to mount a single cylinder engine with the normal Kadet "cheeks".
As I have said before, my model is going to be a work in progress and be used for experimentation and so I need a bit more flexibility than I can get with the excellent Great Planes mounts.
This all started because my ARF Kadet has over its life had a Saito 65, then the Saito 90TS twin then an ASP 91 and most recently a Thunder Tiger 54 four stroke. I tried to put the Saito 90R3 radial in it but there were so many holes I was unable to drill holes where I needed them and at that point I decided on the removable false firewall for the next model which is currently under construction (slowly). So far I have half a wing built.
Mike in Oz