Probably no biggie to you guys but I did my 1st Knife Edge loop yesterday. It was a little small, but now that I know I can do it I will start working on increasing the diameter of the loop. I also took the avice of a fellow flyer and cranked up my high elevator rates to 120 (Futaba 9C) and I was able to finally do some really nice elevators without tipstalling uncontrollably. The wings want to rock a little but managing the fact that I can keep it from tipping over while it falls is the fun part! This is such a blast!

And yup, this is the one that I have to replace the bad CA hinges on the rudder..[8D]

Ok, I'll bite on this one...congrats! It's a biggie to me because I've never done one yet . But you didn't say what plane you were flying.

Congrats on one more trick you can check off the list!!!! Although most people I know try to get them smaller as opposed to bigger, ultimatly ending up in a kife edge waterfall or even a pinwheel.

What airplane were you flying??

U CAN DO .60, OS .91FS. Fun plane! Actually the first time I pulled it off was an accident, I gave too much opposite rudder and next thing I knew I had done it! Only about 15' in diameter but it was a KNE none the less. So I tried it again a few more times and it seemed pretty easy to just give enough rudder to make the loop and just balance with the ailerons. The harderst part is the last 1/4 of the loop. Working throttle, rudder and ailerons all at once while overcoming the B-Hole pucker factor and the urge to bail out is a lot to manage at once. I tried bigger loops but they are much more difficult to manage in the last 1/4 have to really focus, I havent quite been able to cleanly get around without rolling over to inverted and wobbling around right at the end of it. I think the key is to have your plane trimmed so that all you need for a straight knife edge is rudder, if my plane didnt go in a straight line it wouldnt work for me. ALso Im trying this about 150' off the ground.. Ive only been RC flying since September but man I am hooked!! What a fun hobby..

To do nice KE loop, you will need to maintain speed for 1st quadrant while having enough thrust for 2nd quadrant. 4" pitch won't work too well. .91 FS (the 4-stroke) may not have enough power. My UCD w/ Saito 100 using APC 15x6 has just enough power for nice, large, round, and most importantly, even speed, KE loop.

Oh, for UCD, the less tail heavy, the less rudder coupling. Just the opposite of 3D need of CG.

My Excite 90 does a nice KE loop. Its real stable in K.E., and the coupling isn't too bad. I mean I mixed it out but usually I still get some coupling when using lots of throw, like in the last quadrant. Not with this ship, though.

Mine will do it, its just got too much of me in the sticks to make it pretty when the loop is large. I can make a large KNE loop, but like I said I seem to get adverse roll in thelast quadrant. BTW, I am flying with a 15x6 APC prop, 30%Nitro 18%oil fuel.

BTW can someone explain coupling? I havent the foggiest what you guys are talking about, havent heard anyone use it at the club!??

It's when your plane moves in an additional axis when you use a given control. For example, giving a lot of elevator in a loop and having the plane start to roll as well even though your ailerons are neutral. Or doing a knife edge, with rudder only, and the plane starts to move in a pitch direction, towards you or away from you, even though your elevator is neutral. Some guys will mix such tendancies out with their computer radios if there's a consistent effect. There might be a more scientific explanation but that's coupling in a nutshell.

For Knife edge flight or point/slow rolls, coupling is easy to deal with because you're not using much rudder throw. So a little computer mixing can really take care of a plane which pulls to the canopy or gear in knife edge. When you start doing KNE loops and lollipops, which use more throw, my experience has been that the coupling increases or even changes how it is manifested as you approach full throw. So the same mix you used for pattern maneuvers might not do it. My radio (9C) is supposed to have exponential mixing curves to aide in this, but I haven't tried them yet. For now, on my Goldberg Extreme, when I do a tight KNE loop, I just have to add a bit of alieron.

AeroDave... what is a lollipop?

John,
Its a tight knife edge loop from a hover, returning to a hover. More like a piroette (sp)

lets say I need some elevator mixed to my rudder to do a straight knife edge,
do you guys put this mix on switch?
If not, everytime you used your rudder for other moves it would have up or down elevator movement mixed in, which wouldn't be good, right?
dhauch

I don't. I just leave it on all the time.
My smallish brain thinks that's because coupling exists anytime the rudder is used. i feel its just not as noticable in something like a stall turn. I could be wring, though. I will say this: I use the rudder constantly, and haven't noticed any ill effects from the mixing.