As far as the Great Planes Reactor is concerned, it depends upon which one you are asking about.

The tech notes says this one has Monokote covering: GPMA1021 REACTOR .46-.70/EP 3D ARF

The tech notes don't say what kind of covering on this one: GPMA1540 REACTOR 3D EP PERF SERIES ARF

This one is Monokote-covered: GPMA1580 EP REACTOR BIPE 3D ARF

I can only go by the tech notes.

Per my original post, the Great Planes Skybolt ARF has Monokote covering except for the bottom of the wing with the checkerboard pattern. That is not Monokote, but a different material.

If you call Great Planes Product Support, they can only provide the answer that's on the sales sheet or in the tech notes...it's the same info I have.

[edited for typos]