OK, I finally made up my mind and bought a evo .46ex BB engine today. I thought I had an OS.46AX bought and it backfired so sprung for a new evo. Anyway it weighs more and its is going to throw off the center of gravity. Should I add weight to the tail or move the battery to adjust the COG? Any help would be appreciated. If it comes to heli's I can handle it but new to planes. Also what prop manual says a 10.5x6 up to a 11x8. I am running this in a hobbico superstar 40 trainer. Thanks in advance. Mike

Move the battery.
On a trainer slightly nose heavy will not hurt a bit.
I would run a 10X8 or 11X7 Master Airscrew prop. They can handle quite alot of abuse and perform well on a trainer.

Thanks, if I were to run the 10x6's I have serveral of will that hurt anything? I also have a couple of 11X5's? Mike

Those props should be fine.

Always avoid adding dead weight to a plane, so if you can get the right CG by moving the battery, then do that. If you still cannot get it with the battery moved as far back as you can get it, then you can either buy a larger capacity battery that weighs more, or you can add some dead weight. If you get the bigger battery, then you are still adding weight, but it is not just dead weight, you now have a battery that will last longer.

Thanks I appreciate the help. I got the weights of off both engines and the new engine weighs 7.46 ozs more than the old engine. I am sure I am going to have more power than I need but I can always use it in the next plane. Have a great day all. Mike

I am not sure what battery I have now but I can fly all day and not have any issues with the battery. I will try moving the battery back and I have an once of stick on weights in 1/4 once increments if needed. I am hoping the battery being moved will do it, there is quite a bit of movement according to the manual. Thanks all and have a great day if tomorrow is as nice as today I will be flying tomorrow evening after work. I cant wait to see the difference this engine makes. I increased my horsepower by .64 HP so it should get up and go right away. I will have to take it easy when flying but at least I know I can get off the ground now.

Never, never, never add weight if you don't have to! Weight is the enemy.
Move the battery. There have been cases where I have even cut out a compartment in the rear portion of the fuselage for the battery, just to avoid adding weight.

The 10x6 might be a tad small for the .46 evo..... just watch over-revving on WOT and you should be ok. Running it rich will help. That prop will be perfectly fine for cruising. A better choice for the trainer/evo.46 would be a 11x5 or 11x6 for a little more pulling power, but I'd wait till you need a prop rather than run right out and get one. It won't be THAT much different. The higher the pitch the faster the plane tends to be..... generally. Other factors apply though.

Once you get comfortable with the plane, use the tried and true 12.25x3.75 APC.... and enjoy!


Read up on RCU for evolution tuning. I think you'll find the Evo is a fine engine, but you might find you have to do soemthing with the needles later on. No big deal, just something to plan for.
My buddy's Evo .46 throws his plane around like a rag doll..... It has amazing power compared to the others we've tried. YMMV

I have a couple of 11x5's now I can put on there it just said that I should run the first few tanks with a 10.5x6-7 so I was not sure if there was that much difference between the 103.5x6 and the 10x6 only a half inch but I can run the 11x5 or I have an 11x6 as well. Thanks Mike