Somethin Extra....
 

When I fly my somethin extra and go to knife edge it won't hold. Is my plane the only one that won't knife edge or is the plane just not able knife edge well? Oh and my high rate for rudder is as far as it will go and I have a O.S.46fx with a mag pipe so I sure that is plenty of power.

Somethin Extra....
 

I added 1" to my rudder as I had heard this was a problem w/ the S.E. I still could not maintain extended knife edge. I did not mess with the cg much, but I suspect that I could have moved the cg back a ways to help w/ KE and it still would have been fine for everyday flying. BTW, I put her to rest one day while hovering about 15' and my trusty Thunder Tiger .46 pro sputtered and died!!!!!! May she R.I.P.!!!!

regards,

Astrohog

Somethin Extra....
 

I moved the C.G. back a little at a time, and increased the rudder by glueing an inch and a half to the rear of the rudder. The plane knife edges well now.

Somethin Extra....
 

Knife edge flight has always been a weakness of the SE. Mine was an ARF with stock rudder, but even those that added an inch or so to the rudder complained about it's weak knife edge. I'd suggest *****g out the throw on the rudder, moving the CG back and making sure you have a fairly strong servo back there. It still won't be great, but better than stock.

Somethin Extra....
 

I am able to fly KE circuits, but only at full throttle. (an experience in itself, the SE doesn't like speed much)

Anyway, that is with an irvine .53 and a 1 inch counter balance on top of the rudder. CG is at recommended stock location.

Somethin Extra....
 

If you get your CG back enough with the original rudder it knifes well. You guys have to remember that you can go way back with the CG before this plane dolphins. The more toward the tail the CG is the more 3D this little wonder becomes, the flatter the spins, the sharper it snaps, etc. I spent many hours working with moving it back on mine but mine was the kit and not the ARF which makes for a lighter SE. I can tell you that the further you get it back the less input you need from the rudder, so use that for fuel for thought and see what you can do to make it the most fun possible.

Somethin Extra....
 

It also would have helped a great deal if they would have designed the tail section with more than 30 degrees of rudder throw

Somethin Extra....
 

Biggest problem with the SE and knife edge is its profile. Mine's got an inch added to the rudder, 3/4's added to the elevator and the elevator's modified to allow 45+ degrees throw on the rudder, AUW of 4lbs 10oz with an Irvine 53, last time I flew it the cg was at 4 3/4". It knife edges, and it will climb in knife edge (won't ke loop) but it takes full throttle and a load of rudder. It pulls pretty hard to the belly and when I input up elevator to correct that causes it to roll to the right which is correctable with ailerons. It'll do laps in ke, but that's about its limit. Gonna try changing the fuse profile (been wanting to do that since Christmas, boy this winter stinks) and see if I can improve the ke and get rid of the coupling.

Mike