It will fly on a 70, however the plane will not have the power to do some of the 3D stuff. It will power similar to a low wing sport plane, not a 3D plane.

The plane was designed around the OS 91 four stroke. Many are flying the plane on Satio 100's and a few have stepped up and put YS 120's.

I flew mine off a OS 91 two stroke with a Jett muffler and it has plenty of power. If I were to do another UCD, I would power it with the new OS 91 FSH-C. The new black heli version with the Hyper Head and the Jett muffler.

If you have a 70, use it. It will fly the plane. Once you get comfortable with the plane, go to a bigger motor and really see what the plane will do.