Hiya Tom!
Unlimited vertical performance is not necessary, but possibly desirable in this case. A few times, I witnessed my friend's OS 91 surpass powered hog wallowing over the crowd of people on the verge of stalled mayhem...you now the scene...left wing dropping due to torque, he's standing on the right aileron stick and nothing is happening so he nails the right rudder and it flip/snaps over to the right, oops! We're heading for high alpha inverted flight here, then by some kind of a weird miracle he makes it out of that one and says: "Did you guys see that?!"


All I'm saying is it wouldn't hurt to have a little more oomph. Now, the next size up is a 1.20 which is a 20cc power plant and if this guy can fit one under the hood I say more power to him! Pun intended!