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Do most use mixing to make knife edge easier?

Philip3

Junior Member
#1
I've had a AS3X Beast for a while now and knife edge well with it. Also, I practice on Phoenix sim all the time and have no problems holding a knife edge. The problem is on scratchbuild planes I have. I have built the FT3D, RCPowers Extra300, and a large profile version of the beast. They all fly great, but when I try to knife edge they roll over and I fight to hold it.

Is there something missing in my setup? balance? mixing? Any help would be appreciated.
 

Philip3

Junior Member
#2
I found a great thread in RCGroups by Bonedocs which answered my question and then some. He even had a 12 minute video demonstrating how it is done. :) I love the internets :p
CG and Rudder>Aileron / Rudder>Elevator mixing are key to working this out.
AS3X does this for you somewhat, but I'm going to play around with mixing it too to see if it is even easier to knife edge.
 

Ak Flyer

Fly the wings off
Mentor
#3
You need a very well trimmed plane to hold a good knife edge. When you are flying straight and level, it should maintain that on it's own. I notice a trend when flying indoors for people to trim the elevator up to assist in very slow flight. The problem with this is that when you go inverted or knife edge, the trimmed effect is now working against you. Ideally you should have all control surfaces perfectly straight so whatever attitude your plane is in, it won't have weird tendencies.
 

Vent

Junior Member
#4
When I flew many years ago I was starting to learn some pattern flying from a pattern champion here. It was fairly common to actually trim the plane so that in a vertical dive or climb with no stick input the plane would stay true and strait - this means that in normal forward flight you would have to hold a little up elevator to stay level and around the same of down elevator to stay level whilst inverted.

By doing the above in a dive/climb/knife edge your plane wont have a tendency to want to pull out of it. I wonder if many serious 3D pilots trim the same way? To me it sure makes sense.
 

Ak Flyer

Fly the wings off
Mentor
#5
That's a good idea, hadn't thought of that. I don't really know what mixing you would have to do to get a knife edge specific mix. Would that be something you turned on when you were only in knife edge? What if you turned it on at the wrong time or the wrong side and it caused a crash lol. I've heard of such a thing, just haven't ever used it. I trim my plane as neutral as I can and practice by doing laps around the gym we fly in trying to stay right over the basket ball court baselines. Cirlcles are easy, I find that following the box pattern is much more challenging.