Ok, had 4 flights on the Reactor yesterday and 2 today. In all of them I had only one goal- to make the thing hover. Started with a 13x4 which I could hear was over-revving and gave me the soft compression problem again when hot though it didnt cut. Then used a 13x6 which was much better but still couldnt hover. Today, I tried a 12x6. Also Last week I already tried out a 12x8. In the hover, even at 100% throttle and full rudder and elevator throws, the plane could hover for a second or so before falling nose down. It fell nose down everytime, did not slide backward or left or right. Today I even got a buddy to make sure I was at full throws and full throtthe when that happened and he confirmed it. And it happened with every prop

I have already checked the CG and its ok if not a bit tail heavy. I flew today with a much lighter 1300mah LiFe battery under the tank to make it tail heavy.

That settles it. The 55ax with whatever prop doesnt have the power to 3D the Reactor, atleast not with my reinforcements. It just lacks the last 10% of power. So while I resolved the engine issue with a 12x8, the engine just doesnt have enough grunt, even with 10% nitro. It is great for pattern flying but not for 3D

I am contemplaing which engine to put in

1) FS91SII- I have this engine in good condition on another airplane. Rather than keeping it unused, I would like to use it on the Reactor. Total weight is 24.2oz (686g) with muffler and that is comparable to a 65ax and is lighter by 2.26oz or 64g than the 75ax. This would be the economic way to go

2) 75AX- had issues on another airplane but those may be due to tank height problems. Has a lot of power by is heavier

3)65AX- has only marginally more power than the 55ax. Is a bit heavier too. I dont have this engine though

Please Suggest

Ameyam