RE: Everything Radial Engines
Nils, I have had the Kankge Monocoupe and a Saito 325 R5 as a project two years ago, I think, Didge is right, as on nearly all ARF kits You will have to strengthen the fire wall for the fife cylinder. as I remember, the servos for elevator and rudder are mounted underneath the stabilizer, so if You fit the receiver and battery at the same place, may be You will only need little additional weight to balance correct.
What I remember too is, that the distance between the bubbles for the valve covers on the cowling is a bit too wide, so You must either cut the cowling between the bubbles or cut the bubbles and fix them at the right place to fit the Saito. On my project I made the modification with moving the bubbles to the correct position.
I did not finish the Monocoupe and sold it again, because I purchased the Aero for my Saito engine. I know several ARF GeeBee Sportsters here in Germany flying with OS or Magnum radials, and the combination works really good, inspite of the extra weight, so I think You must not be affraid. The only thing I was thinking over was eventually strengthening the landing gear.
Holm und Rippenbruch,
gnome