Are they interchangeable?

[siang]

What is the difference between plane and heli glow engine? Are they interchangeable?

[RCModelReviews]

Heli engines have a larger head that acts as a better heat-sink than an airplane engine and they usually have different carbs that are designed for more constant RPMs over a wide range of loading.

You can interchange them but it's really a whole lot better to use a heli-engine for a heli and a plane engine for a plane.

The heli-engine probably won't throttle or transition as well as the plane engine when hooked up to a prop and the plane engine may tend to run too hot when in a heli.

[siang]

, thanks Bruce, now I understand