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Pitch Coupling Mixing - Leave it on ?

Old 10-21-2003, 11:07 AM
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SBeachman
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Default Pitch Coupling Mixing - Leave it on ?

I guess I have a basic question for most IMAC flyers.

When you add a mix to your plane to 'zero' out pitch coupling in knife edge......

Are you guys leaving that mix on ALL the time ??

So, in other words.........is it on during a Hammerhead ??

Is it on during Spins ?

My thinking is it should be, if that's what the plane needs to 'not pitch' when you apply rudder.

Any tips ??
Old 10-21-2003, 12:39 PM
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Flyfalcons
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Default RE: Pitch Coupling Mixing - Leave it on ?

I leave my mixes on all the time. I usually run a rudder - elevator mix, a rudder - aileron mix, and a throttle - elevator point mix. I've found that if you hit the rudder in knife edge and the plane pitches to the belly, it also usually pitches to the belly when you hit the rudder in level flight.
Old 10-21-2003, 03:27 PM
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Default RE: Pitch Coupling Mixing - Leave it on ?

I like to turn off any mixes that will make landings interesting -- like down pitch with throttle that keep down lines straight...
Old 10-21-2003, 09:17 PM
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Default RE: Pitch Coupling Mixing - Leave it on ?

You're exactly right. If the plane needs a mix to fly straight, then leave it on all the time, all maneuvers. If throttle mix is a problem on the landings, then the CG needs to come aft to fix the landings and the uplines. Have fun!

CJ
Old 10-21-2003, 10:09 PM
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SBeachman
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Default RE: Pitch Coupling Mixing - Leave it on ?

I really appreciate all the feedback.
It amazes me how fast, and helpful the R/C Universe community can be.

THANKS ALL !
Old 10-21-2003, 11:05 PM
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Rcpilot
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Default RE: Pitch Coupling Mixing - Leave it on ?

I don't use any mixing.......NO, I'm not a great pilot.

The guys around here that fly with mixes, usually look better than I do. But, an old friend once told me, "Fly the plane, not the TX." I guess it stuck with me.

Nothing wrong with mixing, I just haven't ever used them.
Old 10-22-2003, 02:33 AM
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Default RE: Pitch Coupling Mixing - Leave it on ?

Have an AW37% Extra that snapped on landing with deadstick in crosswind due to rudder/ele mix on(and it wasn't much) Don't need the nose pitching up or down as you give rudder to compensate for crosswind landings.

I always turn the mixing off for landing and takeoff.

Ed
Old 10-22-2003, 09:51 AM
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Blow n Go
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Default RE: Pitch Coupling Mixing - Leave it on ?

AW extras are very well balanced aerodynamically and shouldn't need much - or any - mixing at all. If your mixing was enough to cause a snap, there must have been other issues at work, like a CG problem.

The sole purpose of adding mixing to an airplane is to balance an aerodynamic imbalance that was "built" into the plane by its design. Examples are a stab at the wrong height or wing dihedral. The most extreme examples are bipes, that often need 25% or more rudder to aileron mix. Another reason for mixing is laziness. Rather than going to the trouble of changing engine thrust, which is a pain, I could use a mix to adjust the rudder or elevator as I advance the throttle. It is still an aerodynamic flaw I am correcting, though.

A perfectly designed and set-up aerobatic plane needs no mixing. The AW Extra is as close to perfect as I have seen. AW has done the homework for you and moved the wing and tail from their scale positions to balance the plane. Other extras may or may not be as well balanced.

If a plane needs mixing, then mixing will not get you into trouble.......if you do it correctly and only use enough to get the job done. If a plane doesn't need mixing - and many newer designs don't - then you are better off for it. If the plane does need mixing, though, it needs it all the time.

CJ
Old 10-22-2003, 11:34 PM
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Default RE: Pitch Coupling Mixing - Leave it on ?

I have figured that I need various pitch correction in different maneuvers and don't need as much as others. The main difference is having a flight mode pitch corection without opposite aileron for stall turns and rolling circles . Until I figured that out, my stall turns, rollers and 1+ slow rolls didn't look that good! Only my normal flight mode has a hint of oppposite aileron correction in with the up ele mix. I rarely fly just a long knife edge, therefor I adjusted my mixes just for the maneuvers I was actually flying plus what I thought might be coming up in unknowns..

Dave

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