Flight Mixes, do they really help?

[Mr.Willow]

Hey, guys, just a quick question here.
I'll be putting together my first giant scaler and been thinking about all the mixes and stuff. So I'm wondering: If I program some mixes to correct bad tendencies of a plane, will these help me when the plane is, lets say inverted? Or just make things worse?
I mean one could set up a whole bunch of mixes, but they would need to be switched on and off all the time depending on aircraft's position, right?
Ok, I could program downline mix on low throttle and switch it off on landing, but what about all the knife edge, rudder to aileron and other mixes I may (hopefully not ) need?

Thanks

Chris

[Tired Old Man]

There has yet to be made a kit plane that is absolutely neutral. Every one will exhibit some type of unwanted roll, pitch, or yaw coupling in one attitude or power level from another. Just a simple change in propellers can impact flight attitudes and couplings.

One always has a choice in using or not using a mix. If they believe they are good enough to always anticipate and manually correct for coupling actions when they try to fly precision maneuvers without mixing and fly precisely. It's not possible but there are those that fool themselves into believing it can be done. They are usually the same ones with a computerized 10+ channel radio with all the whistles and bells, but with none of them other than servo reversing and end points utilized.

The effectiveness of a mix is completely dependant on how the owner sets up the plane. If they take the time to work engine thrust angles, using zero as a base starting point, nail the c/g, and have correct wing incidences, then any mixing will be minimal depending on the original plane design.

The choice to use mixes switched or always on is up to the owner. Many have found that some mixes, such as rudder/elevator for knife edge stuff, work just as effectively in other flight attitudes.

[Mr.Willow]

Thanks for the detailed explanation. I'm not saying mixing is bad or anything, just wondering whether mixing out one bad tendency does not result in another one at different attitude, but I guess it all boils down to the set up and how much of a mix is needed..

Chris

[Tired Old Man]

Some mixes can cause differences when used in the opposite direction, but those are usually incurred in a vertical attitude. Even those are not much of an issue when set up correctly, such as mix on with throttle, mix triggering to no mix with zero or reduced throttle.

Most of mixing is in understanding what needs to be done, and in what amounts. It takes time, many,many trim flights, and often a little help. The most useful help you will have will be with someone to take notes as you fly all the trim flights. Mental notes all to often get lost during the landing approach

[Shahid B]

	Quote:
	One always has a choice in using or not using a mix. If they believe they are good enough to always anticipate and manually correct for coupling actions when they try to fly precision maneuvers without mixing and fly precisely. It's not possible but there are those that fool themselves into believing it can be done. They are usually the same ones with a computerized 10+ channel radio with all the whistles and bells, but with none of them other than servo reversing and end points utilized.

Bit of a generalisation that, I fly freestyle routines without mixing as it allows me to get on with it without having to flick a switch everytime I KE, and my model is Katana so has alot of coupling, which means If I left the mix on all the time it would adversely affect everything else.

I can understand if you'd want it for pattern, oh by the I only have a DX7

[Tired Old Man]

How well do you think you could do flying medium to upper levels of IMAC without mixing? I don't know about you but I'm a 3d flyer and I would not even bother getting out of bed to compete against half way decent IMAC competitors without having a plane as dialed in as it could possibly be.

With 3d you have the opportunity to use any natural coupling to work for you. That benefit just isn't there in precision flight. As for a KE mix, I used to have it switched but I found that as the mix got as close to making the plane neutral as it could the plane flew better all the time with it left on...

[Doppelganger]

Some of the IMAC pilots I know switch off their mixes when landing. I only dabble in 3D and the only mix I use is spoilerons doing a harrier (stops wing rock.)

Steve

[Shahid B]

I agree mixing helps when flying higher levels of precision competition, and I didn't disagree on this point in my earlier post either!

What I didn't agree with is that it's always needed (as I pointed out) and would actually be deterimental to some flying styles, especially where large throws are concerned. I also didn't agree with the general "people with computerised radios" comment, as I don't typically use mixes but I only use a DX7. Not a 10 channel with bells and whistles.

[3D-Seth]

I use mixes for both IMAC and Freestyle flying, that stay on all the time. A lot of people don't realize that you can't just use a linear mix to mix out coupling in knife edge, it needs to be done on a curve, this way, anywhere from 5-50º of throw, you won't have coupling. Another thing, I set up a downline mix to only work on my last two "clicks" of throttle when I am doing a figure that will have a downline. With this, I only have this mix on in my normal flight mode, as well as my spin/landing flight mode when the throttle is at idle. Does not affect the way the airplane lands. If the time is taken to have certain mixes automatically "shut off" per flight mode, it makes it MUCH easier on the pilot. Any well trimmed airplane can fly VERY well.

Seth

[notorious_benny]

If your model needs a knife edge mix then it needs it all the time, no need to switch in and out of it.
The trick is not to set up, for example, a knife edge mix that is completely linear to the rudder, you might find that the mix is only neccessary up to 20% of rudder throw and beyond that no extra elevator or aileron is needed, so program that into your radio using a multipoint curve.

I will admit that I mainly fly IMAC and have found that I need only very minor mixing to weed out pitch and roll coupling, I have never needed a 'downline mix' (proper trimming fixes that one), and when I do get out and have a crack at 3D I find that the mixes I use have no negative effect on the model whatsoever.

I say leave the mix's in and get on with the flying!!!

[notorious_benny]

Ha ha, looks like Seth and I posted similar thoughts at the same time!

I should have elaborated that the knife edge mix works in all attitudes, if your yawing in level flight with rudder only the mix will help prevent the model diving or climbing erratically, this can also be extrapolated to having the model inverted and then anywhere in between, such as a one roll rolling circle.

[Mr.Willow]

If the plane needs KE mix, it needs it all the time- that's what I was not sure about, now it's clear.And the best solution would be to set up mixes so they don't need to be turned off...

Awesome stuff, I've learned a lot

Chris

[bodywerks]

Don't think of it as a knife edge mix - it is a roll coupling mix and a pitch coupling mix. If in knife edge the plane pitches toward the belly and wants to roll in the same direction as the rudder input, it will have this tendancy in any attitude, beit upright, invertedm on the vertical line, whatever. So the mixes need to stay on, even for 3D. The only time I have benefitted from putting my mixes on a switch is when I am flying a plane that was not intended for precision flight, like an ultrastick, where ther is so much roll coupling with rudder that it would roll with rudder alone. It's great to add 18% of opposite aileron mix and 14% down elevator mix to compensate for this so that I am not constantly fighting KE and flat turns. However, because the coupling is so bad I lose 18% of my aileron throw and 14% of my elevator throw whenever I have full rudder deflection. So in a positive snap,for instance, the plane rotates too slowly with the mixes on, whereas if I turn them off, the roll/pitch coupling actually helps with the snap - and believe me, an ultrastick needs that help!
The other thing to understand is that programmable mixes should be the LAST part of your setup. CG should be the first thing, then prop selection, then thrust angles, then aileron differential, and then finally mixes. Of course incidence is important, but people rarely expect to mess with that with an ARF.

[JoeAirPort]

No brainer that mixes are better. But I haven't been using them believe it or not (and fly the hell out of my aerobats). I just fly the airplane and give the stick inputs needed for whatever I'm doing. If I competed I'd certainly take the load off my thumbs so I could concentrate on the routine and my precision. But I don't so I just use my thumbs. If you buy well designed, good quality planes, know how to tweak incidence, and move CG's around, the coupling really isn't bad from my experience. After I got better at flying I sold anything that wouldn't fly on its side. There are plenty of fun flies out there that are horrible in knife edge flight. I should make it a point to do some mixes on my two aerobats. I usually get to the field and just want to fly. The three I'd add are for pitch and roll coupling. I'd also add some down on low throttle for landing. They are both pretty tail heavy (totally neutral).

[SleepyC]

Mixers rule.
Drinking rum straight up hurts my stomach.