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Old 09-23-2012 | 07:56 PM
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MTK
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From: Whippany, NJ
Default RE: Pattern design question


ORIGINAL: Ryan Smith

I noted a huge difference in flight performance on my Partner (which I had flown for five years prior, so I knew a thing or two about how the airplane flew).

Anhedral stabs give the effect that Archie noted, but there are some negative side effects- chiefily positive and negative snaps are very inconsistent from one another and the airplanes that I've flown with them didn't particularly seem to lock in. Personally, I haven't seen enough benefit to outweigh the negatives of having anhedral stabs, and I have seen a huge advantage to the use of a canalizer.

Your mileage may vary.
I've used anhedral on a couple designs in the past and my latest also has the feature. I tend to agree with Ryan and Archie that not every model benefits from anhedral. My latest tends to not lock as well as I want. I have also found that CG latitude (how far one can move CG) is diminished considerably. Running CG a bit aft, is a big no-no. Cross wind flying with CG even at 33% MAC is two handfuls. I suspect that one should not use anything further aft than 28%MAC. I am currently running my CG at 30% MAC and it's barely passable. I abhor having to add nose weight............

On current 2m models I don't see much benefit and will not use the feature again in any future design that is 2 meter or larger

On the other hand, a dorsal fin at midships helps a great deal in the way Archie mentioned. Consider why a shark is an apex predator.....take his central dorsal away and he becomes bait