As you may have read by some of my other post I have a TF Arrow that I have built and ready to put in the air. My big concern is that the OS .61 is going to be way under powered after hearing some others input. Can't really afford to buy another engine. I did purchase some additional props such as a 13X6, 12X6, and a 11X7 to try and get more power out of the 61. I do have a Magnum 70 four stroke which would require replacing the mount and maybe modifying the cowling. If in fact the .61 is way underpowered for this plane what is the best approach to flying this thing on its first flight? What prop should I start with? I just don't have the experience on this type of situation and as much as I don't want to put more work into the plane I don't want to crash it on the maiden flight either. What and how would you folks handle this situation. TF does call for a .61-.90 size 2 stroke or a 70-91 four stroke. So either way I would be on the bottom of the spectrum. The plane now weights in at 11.2 lbs. As always thanks for your input.

chopper