ORIGINAL: speedracerntrixie
ORIGINAL: AA5BY
ORIGINAL: speedracerntrixie
Everything the OP has said so far indicates the airplane is nose heavy. The other trimming suggestions and articles are of little help until the CG is set correctly.
I'm not getting how everything the OP has said indicates a nose heavy condition. I've reread the OP's post and he says it is balanced at 2.85'' aft of LE. That point is confirmed to be the published CG by John Gilmore.
Sorry gus been away for a few days.
Indicators of being nose heavy. The first would be the requirement for excessive up trim. As stated by later posts, the OP states just a tad of positive wing incedence. This is the way I set up all my aerobatic models. I usually set up a model with a CG that requires no elevator trim. The 45 degree upline test is a good way to verify CG. If no elevator trim is required and it stays on an inverted 45 hands off or slightly pulls to level the CG is correct.
Pulling to the canopy in knife edge. Almost all the airplanes I have owned that are capable of knife edge will tuck towards the gear slightly when the CG is correct.
Fast landing, Nose heavy airplanes land fast.
The OP has stated that he verified the CG location as per instructions. This doesn't mean that it's 100% the correct CG. It usually mens the airplane will fly. Clearly the airplane is sending indicators that the CG is too far forward. I always get a chuckle when I read test flight results that ends with the model being in perfect trim when a few clicks of this and a few clicks of that are applied. My airplanes usually take about 50 flight to get into 95% trimmed. The last 5% is like chasing a Unicorn.
I think (from pics in manual) that the plane has an asymmetrical foil so KE issues are probably not typical to aerobatic planes. I do agree with you that there have been times that the published CG has proven to not be good.... but Hanger 9 is generally pretty good. I also agree with you that the symptoms fit a too forward CG... I wasn't arguing that they didn't... just that there wasn't enough information yet to conclude that... as at that time, there were no incidence numbers and there was a claim that the model was in proper balance on the manufacturer published number. I was also giving credit to the post by John Gilmore that outlined that the OP had used the smallest recommended engine and thus it should not have been grossly nose heavy, which gave some credence to the OP's claim that the plane was balanced properly.
Last... I'd never get involved in one upsmanship of experience. I respect the experiences of all others. Personally I've never seen a model that required more than one quarter inch of elevator trim that didn't have an incidence problem but I'd never argue that it couldn't happen.
To the OP
Two steps could be taken.
1. Go the Areodymanics forum and in the sticky thread, there are CG calculators. See if they verify the published point. I've used one of those and it nailed the CG for an original design and, though I can't guarantee the calculator will nail it every time... I know it did the one time I used it.
2. Start a thread in the ARF forum and list the model and catch the attention of other owners of the same plane and compare.