I have a bipe which requires alot of mixing to get rid of pitch an roll in Knife edge..........Should you put this on a switch solely OR
could you just fly the plane with the mix on all the time.Would you gain a pure yaw response from the plane all the time ??????????
Like that up elevator you'd get steering the plane on take off.

I depends on how much elevator and in which direction you need. If it pulls toward the landing gear that is sorta normal. Try a flat turn just using rudder. If it also tends to drop the nose then you can program in some up elevator with the rudder. After programming in some up elevator in my DP 330L to get it to knife edge in a straight line I tried a flat turn. It doesn't tend to drop the nose any more. We tried the same thing on a Sig Sukoi and it didn't work as well. You'll have to try it. FWIW. I needed 2% more on one side of the rudder than the other.

Programming is not a problem.Its whether to leave it on all the time or connect to a switch when you fly knife.......seems like it would just cause a nice yaw instead of the mess it normally creates without mix,,,,,,Is there a down side to leaving it on

bill,

i fly most of my planes with KE mix always on. Not a problem at all even in stall turns...very small correction is need so i dont bother to keep the mix on a switch.

(I dont need too much mix on the planes I currently have)

You will find that leaving the mix on will make elevators and harriers more difficult especially if you need to mix aileron. Bipes tend to roll as well as pitch with rudder input and you do not want aileron input when you are steering with the rudder at high alpha. This is however just my personal opinion based on my experience. :^)

I have a switch for landing mode or flying. During landing mode, I have my KE and fast idle (plus a few others) turned off. You may be able to use something like this. I think that the KE mix should be on for all flying.

Wouldn't this prevent the roll coupling even at a low airpeed and induce a true yaw.with rudder input...This is a problem with bipes in a flat turn....which i consider knife edge in a horizontal plane....

Of course the side load of wind against the fuse is not as pronounced .........

Seems like if you had the plane flying in true axis control inputs ...everything would fly better........

I fly IMAC type stuff..btw

I've been thinking about this alot myself recently, as I have a UCanDo3D that has some severe rudder coupling. I personally feel that the mix can be left on for any forward flight and normal (flying on the wing) aerobatic maneuvers, but I agree with OUTCAST that it can cause problems in high alpha maneuvers like a harrier, and also in a hover when all you want is a blast of prop wash to give you rudder pitch but with the mix on it also gives you a little unwanted elevator that you would have to correct.
This is my feeling for an airplane that has severe coupling issues, like the original question stated. If it were something more along the lines of say an Edge that doesn't couple very bad, I would leave it on all the time no matter the situation.

During a harrier or elevator forward velocity is very slow if at all, and the ailerons are only used to keep the airframe level. Since the amount of roll couple is proportionate to the amount of side loading, at no velocity there is no side load, however large amounts of rudder are needed to maintain directional control. You really don't want the aileron input when upright at minimum airspeed. And if elevator mix is used it will make it more difficult to hover as every yaw input will induce a pitch change, at least thats what my two remaining brain cells think. :^)

CHEATERS!!! I never use any mixes for that stuff!! or gyros ; )

3dbatixkid, every single pilot, with no exceptions ,at last years TOC used mixes. It would be hard to classify them as cheaters.

Sorry, but I agree with 3dbatixkid. Use the brain in your head instead of the one in your transmitter. It will make you a better flier IMHO. If your plane pitches toward the landing gear during a KE, hold a little up elevator. Is that so difficult? Do you use special mixing for a cross-wind landing, or do you manually feed in some slip? You guys will spend hours programming the exact amount of mixing into your transmitters, and then learn to fly at just the right speed so the mix works, but you won't bother to just manually feed in the correction! No, that takes thinking and coordination. Too much trouble.

lets not get ridiculous and start another war here, anyone who has ever flown competition in the modern age will tell you knife edge mix correction is not cheating. It's a competitive advantage to fully utilize the programming features of your computer radio to correct for a given airframes aerobatic shortcomings. During the Freestyle portion of an IMAC contest, should we not mix spoileron to stop wing rock in harriers and elevators? If you think using a mix somehow shows that you don't have the skill or coordination to fly a maneuver properly, by all means show up at the TOC or F3A world championships and share your views with any flyer there and see what their reaction is. To build on what Minnflyer said, your knife edge mix may have been set up on a day where air density and wind direction may have been different due to weather and temperature changes, so you show up at the contest to totally different conditions, the guys at the top of the leader board are using their brains and slightly correcting to keep their headings spot on. The mix will at the very least get the airplane in the ballpark. Cause you know what, the guy in the pit next to you is doing the same thing, and who wants to show up with one strike already against them? "Precision Aerobatics" takes more then a mix to do properly.
Bottom line, if you don't think using a mix is flying, don't use them, the other guy with arrow straight point rolls and KE loops will be glad to let you hold his 1st place trophy! HAHA!

3dbatixkid, then why do you use that fancy Futaba radio?

eness76,

Point well made.

I use the 9Z because it has the best resolution, and all of the OTHER functions that I need. It is the smoothest radio I have ever owned. I don't use any mixes though. I can't believe that the TOC guys use mixes!!!! THE CHEATERS!!

3dbatixkid,
Well technically they're not cheating since the rules allow it.
But I agree with your point of view. Wouldn't it be a hoot to see which top flyers can control their plane with flying skills and not programming skills. That's a contest that would be worth seeing.

If one wants to use programming to play with his "toy", who cares? But it seems to go against the spirit of competition imnsvho .

"lets not get ridiculous and start another war here" --- eness76
(but you seem ready to carry it on?!)

What OTHER functions? You move those little sticks....

nah, I'm not carrying on any kind of war, but I've watched this topic discussed from a distance several times before, so I thought I'd weigh in with my experiences. I've been in or around pattern since I was 8 years old. My family has been into pattern for years before that, long before the advent of computer mixes. We were blessed enough to have one of the worlds top flyers in our club in the late seventies and early eighties so we got to see what talent was all about. This was back long before the days of the aerobatic "box", so the point rolls could be long, and my dad loves to tell the stories about Dave Brown (our current AMA pres) stretching point rolls from one side of the field to the other straight as an arrow. So if you'd love to see today's best use their "flying skills" and not their "programming skills", I doubt it would look much different. The analogy here is much like Paul Bunyon, why use an axe when you can use a chainsaw?
It's really that simple. If you want to learn how to do it without cpu radios, more power too you, it will improve you coordination, I'm not bad mouthing that by any means. That's how I learned, and I can still do a pretty darn good 4 or 8 pointer without any mixes, but it's not illegal, thus it's not cheating, so why not take advantage of the technology. Otherwise I would have never stepped above my old JR Century7 that I used in competition for years.

Well. Lets say I stirred the pot..........Let me also say that I'm not dealing with a pattern plane...Im dealing with a Christian Eagle Biplane.......If you fly an Edge 540, Ex 300, Cap or whatever.... You do not experience the type of coupling I'm speaking of...I'm not talking about holding..what I call a Dab..........Where talking about almost fully cross controlling the airplane......I.m talking about mixing out the huge deflections its takes ...so I can deal with just a dab.........If you've ever flown any Pitts you know what Im talking about.........Not an Ultimate .....Not a Weeks.......
As far as the 3_d concerns....I have none.......
If you're flying a Extra 300 trimmed well....You know that if you add rudder from straight and level you will Yaw /Slide and begin a flat turn......If you add rudder to a PItts...You will get a negative Snap /Spin......Lets try to get back on track........IMO if they wanted the TOC or Masters to be on an even keel.......They'd give everyone the same plane and the same radio..like IROC..What you are able to do with a radio ..is what sells radios....whether you use the features of not..........

I see how it isn't technically cheating......I just think that it isn't needed. I would rater do it with my thumbs, and get my brain to be the CPU that does the mixing.

I think that once you fly the plane a LOT and get used to it....It will become second nature. At least that how it is for me.....

Great topic!! personally i never used mixes untill i flew a plane that a toc guy had set up for a guy using mixes, unbelievable. I had never flown a plane that flew to true, hands off in every attitude!! I feel that the setup is a skill that the top guys use to their advantage, the less work you have to do with the coupling the more you can concentrate on the next menouver and less imputs for the same thing are and advantage. In theory it is cheating but its one of those things that has been introduced and would be near imposible to control. I know some people who have point mixes for rudder to throttle and unbelievable mixes to fix a variety of problems such as bent fuses and strange flight characteristics............ If you cant beat is join it 3dbatixkid I guarentee your flying will improve.

Don't leave the switch on all the time. I did this on one of my planes. On take off I had left rudder, right aileron, and full up elevator. I almost lost the plane on take off because it wanted to snap roll.

well said. My original reply also delt with a plane with severe coupling like your Pitts. Sorry to take things off track there, but if I were you, I'd leave the mix on and have at it!

I dont think so much a snap mix were talking about, most of those are set onto a sprung switch but more a flight mix... Would be exciting though!!