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Old Sep 19, 2011, 11:52 AM
Gone Huckin'
turnerm's Avatar
Charlotte, NC
Joined Jan 2011
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Quote:
Originally Posted by aerofundan View Post
The mix has to be on ALL the time, because the coupling affects the plane at all time.... If you guys put the mix as recommended by the manual, you will see the plane will fly as close to perfect as possible, and it will improve it in all maneuvers! There is no reason to not use the mix... You will see that the difference in knife edge is like night and day!, with no mix, you will have to do a lot of corrections, with the mix on, you will have to do almost no corrections at all! Try it, and i'm 100% sure you will love it.... no reason to set the mix on a switch, it has to be left on all the time!
Well there you go!

I guess I can see using a mix if the manufacturer states that the mix is to be used in order to get the plane to fly as intended and that it affects flight in all scenarios.

But what I don't get is when I hear about people using mixes for very specific things but not for EVERYTHING. To me, this is basically telling the radio to do something that you're too lazy to do!
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Old Sep 19, 2011, 12:01 PM
It's All About Having Fun!
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Joined Jul 2008
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Awesome Dan is right to say leave the mixes on, at least that what we do at the field. Of course, use the mixes in the manual as a guide and adjust according to your AMR. No worries at all as the AMR is a unique bipe that imho flies like a mono. Just enjoy your AMR, it's an awesome bipe
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Old Sep 19, 2011, 12:26 PM
Grumpy old git.. Who me?
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Joined Mar 2006
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Quote:
Originally Posted by aerofundan View Post
put the mix as recommended by the manual, you will see the plane will fly as close to perfect as possible, and it will improve it in all maneuvers!
I've got to disagree on that point. the manual says to mix 7% DOWN elevator with rudder. Unless my AMR is unique that would just make things worse. Mine need up elevator mix, and a lot more than 7%, I'm currently using about 18%. Maybe the % works different on different radios, so I'll overlook that one, but up is up and down is down and what's in the manual is wrong.

Steve
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Old Sep 19, 2011, 12:49 PM
Precision Aerobatics Team
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South Africa, GP, Randburg
Joined Dec 2006
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Quote:
Originally Posted by JetPlaneFlyer View Post
I've got to disagree on that point. the manual says to mix 7% DOWN elevator with rudder. Unless my AMR is unique that would just make things worse. Mine need up elevator mix, and a lot more than 7%, I'm currently using about 18%. Maybe the % works different on different radios, so I'll overlook that one, but up is up and down is down and what's in the manual is wrong.

Steve
Yep, that's an error in the manual that has been discussed in this thread a few times before. The direction of the mix is up ... to oppose the trim on the elevator if the CG is correct.
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Old Sep 19, 2011, 01:22 PM
They Call him Dead!
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United States, SC, Pawleys Island
Joined Jul 2003
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Quote:
Originally Posted by demonGti View Post
Yep, that's an error in the manual that has been discussed in this thread a few times before. The direction of the mix is up ... to oppose the trim on the elevator if the CG is correct.
I know this has been discussed, but would you mind listing ALL the correct mixes for this plane? I no longer have the manual, and as you all know I can not get one
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Old Sep 19, 2011, 03:03 PM
Precision Aerobatics Team
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South Africa, GP, Randburg
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Originally Posted by dead View Post
I know this has been discussed, but would you mind listing ALL the correct mixes for this plane? I no longer have the manual, and as you all know I can not get one
I believe the manual calls for 9% rudder to opposite aileron mix
(rudder right, left aileron up. rudder left, right aileron up)

and 7% rudder to elevator mix
(on left and right rudder elevator moves up)
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Old Sep 19, 2011, 03:26 PM
The SteamRoller
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Joined Oct 2009
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Another good reason to put out a digital copy of the manual, easy correction of errors!
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Old Sep 19, 2011, 04:45 PM
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Middletown, CT
Joined Sep 2009
119 Posts
Speaking of elevator, I had to put in a ton of trim to get my AMR to fly level with the CG right at 59.5mm. Is this normal? It flies great, it just looks odd with the elevator down that much.
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Old Sep 19, 2011, 05:08 PM
Precision Aerobatics Team
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South Africa, GP, Randburg
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Originally Posted by richh73 View Post
Speaking of elevator, I had to put in a ton of trim to get my AMR to fly level with the CG right at 59.5mm. Is this normal? It flies great, it just looks odd with the elevator down that much.
Yes that's normal for the AMR. The elevator counter balance sits about 4mm higher than the horizontal stab at the leading edge. That's what the KE mix neutralizes so the model doesn't tuck to the belly in KE
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Old Sep 19, 2011, 09:49 PM
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Joined Apr 2007
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Quote:
Originally Posted by aerofundan View Post
The mix has to be on ALL the time, because the coupling affects the plane at all time.... If you guys put the mix as recommended by the manual, you will see the plane will fly as close to perfect as possible, and it will improve it in all maneuvers! There is no reason to not use the mix... You will see that the difference in knife edge is like night and day!, with no mix, you will have to do a lot of corrections, with the mix on, you will have to do almost no corrections at all! Try it, and i'm 100% sure you will love it.... no reason to set the mix on a switch, it has to be left on all the time!
Thats got to be the best explanation yet. Basically, what your trying to achieve with the mix is to get a pure yaw (rudder) movement without any pitch or roll. As Dan points out, this applies to all flight conditions.

The old JR 10X had a specific mix for rudder to aileron/elevator for this purpose, and the manual explains that you want to tune it to get flat rudder turns in normal flight (as close as possible) and KE will be nearly perfect as well. Its aimed at getting the as close as possible to the perfect setup of each control surface not coupling with the other.

Of course the caveat is that it is also a matter of personal preference. For some, they may enjoy the plane more without any mixes. Go with what works best for your own style of flying and have fun!!

dead, the KE mix is the only one listed in the manual as being required. Any other mixes you add in are up to you to suit your own taste
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Old Sep 19, 2011, 10:45 PM
If it's to be, it's up to me.
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Sydney, Australia
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I'd like to add that no mix, no matter what can remove all coupling in all attitudes. Aerofundan is right, that it can make it as close to perfect as possible, but no more. You absolutely still have to "fly" the plane in a KE for this reason, but I find I get much more consistent results with the mix on, and active all the time. No need to switch it off anytime, as yaw coupling is always just yaw coupling.

On my radio, I am able to make point curves for the mix and have found that much more mix is required towards the limit of rudder travel. Point mixes help resolve this, but it is never perfect, because the "correct" amount of mix to hold a true line varies with more than just rudder position. Airspeed, yaw AOA, and throttle are always changing, so you almost always are making continuous adjustments to account for those things too.

I think the PA suggested numbers are only just a guideline, and in my case were way off because I am not using the same radio as Shaun. They should be a good starting point for most though. I also found I needed quite a different setting for left KE as for right KE to get it flying how I want.

sub
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Old Sep 20, 2011, 12:57 AM
Grumpy old git.. Who me?
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Joined Mar 2006
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Quote:
Originally Posted by demonGti View Post
I believe the manual calls for 9% rudder to opposite aileron mix
(rudder right, left aileron up. rudder left, right aileron up)

and 7% rudder to elevator mix
(on left and right rudder elevator moves up)
Yep that's what the manual says (but corrected for elevator up mix)

Now the next question to AMR flyers; Do the % mix values advised in the manual actually work for anyone?

I ended up with % values wildly different from those in the manual. I've got:
2% opposite aileron
20% up elevator.

On my AMR these setting allow knife edge to be flown without any elevator or aileron correction, over a reasonable speed range. With only 7% elevator mix constant back pressure would be required on the elevator to prevent tuck to belly.

My CG is set so that inverted required no down, it's actually slightly forward (by maybe 2mm)of the advised 59.5mm 'sweet spot'. Mine climbs when inverted if I put the CG that far back, and needs even more up elevator for KE. My control throws are as per manual.

I'll be the first to admit that I'm a novice when it comes to knife edge flight but I can tell if a plane is flying straight or not. One thing I do notice is that the amount of elevator mix depends heavily on your knife edge style; both how fast you do fly (faster needs less mix) and also on if you hold the wings truly vertical or just slightly off vertical in either direction (flying 'semi-inverted' needs less mix, semi-upright needs more).
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Old Sep 20, 2011, 01:39 AM
It's All About Having Fun!
The Hitman's Avatar
Joined Jul 2008
336 Posts
Quote:
Originally Posted by JetPlaneFlyer View Post
Yep that's what the manual says (but corrected for elevator up mix)

Now the next question to AMR flyers; Do the % mix values advised in the manual actually work for anyone?

I ended up with % values wildly different from those in the manual. I've got:
2% opposite aileron
20% up elevator.

On my AMR these setting allow knife edge to be flown without any elevator or aileron correction, over a reasonable speed range. With only 7% elevator mix constant back pressure would be required on the elevator to prevent tuck to belly.

My CG is set so that inverted required no down, it's actually slightly forward (by maybe 2mm)of the advised 59.5mm 'sweet spot'. Mine climbs when inverted if I put the CG that far back, and needs even more up elevator for KE. My control throws are as per manual.

I'll be the first to admit that I'm a novice when it comes to knife edge flight but I can tell if a plane is flying straight or not. One thing I do notice is that the amount of elevator mix depends heavily on your knife edge style; both how fast you do fly (faster needs less mix) and also on if you hold the wings truly vertical or just slightly off vertical in either direction (flying 'semi-inverted' needs less mix, semi-upright needs more).
Hi JPF, the values of my mixes differs from the manual but I did use the rates from the manual as a starting point. No doubt it took a few flights of taking off and landing to readjust the mix until I was satisfied with them. I do fly with different CG too so that sometimes mixes things up slightly more
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Old Sep 20, 2011, 01:58 AM
Precision Aerobatics Team
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South Africa, GP, Randburg
Joined Dec 2006
2,018 Posts
Quote:
Originally Posted by JetPlaneFlyer View Post
Yep that's what the manual says (but corrected for elevator up mix)

Now the next question to AMR flyers; Do the % mix values advised in the manual actually work for anyone?

I ended up with % values wildly different from those in the manual. I've got:
2% opposite aileron
20% up elevator.

On my AMR these setting allow knife edge to be flown without any elevator or aileron correction, over a reasonable speed range. With only 7% elevator mix constant back pressure would be required on the elevator to prevent tuck to belly.

My CG is set so that inverted required no down, it's actually slightly forward (by maybe 2mm)of the advised 59.5mm 'sweet spot'. Mine climbs when inverted if I put the CG that far back, and needs even more up elevator for KE. My control throws are as per manual.

I'll be the first to admit that I'm a novice when it comes to knife edge flight but I can tell if a plane is flying straight or not. One thing I do notice is that the amount of elevator mix depends heavily on your knife edge style; both how fast you do fly (faster needs less mix) and also on if you hold the wings truly vertical or just slightly off vertical in either direction (flying 'semi-inverted' needs less mix, semi-upright needs more).
Here's the thing... the percentages quoted in the manual are peculiar to an exact CG and Shaun's TX. Varied CG will required a slightly different elevator trim and in turn a different mix %. So like MalaysianFlyer said, use the manual as a starting point and tweak from there to suit your aircraft and CG location. It so happens that mine was set up exactly like the manual says (ok apart form the the down/up issue) and my percentages ended up being 5% R->A and 8% R->E.
Another thing to consider is the speed at which you fly KE. One would think the slower you fly, the greater the effect of the mix is because of the amount of rudder required. I think the speed therefor has a big role to play in the figures you end up with.
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Old Sep 20, 2011, 05:44 AM
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Middletown, CT
Joined Sep 2009
119 Posts
That's the other thing different with the AMR than my other planes. When I'm flying inverted, I actually need to pull back on the elevator a little for level flight. Every other plane I have is either hands off inverted or push the stick forward a little.

I didnt say up or down elevator because I'm talking inverted and trying to wrap my meager mind around up and down elevator during inverted flight can only lead to madness :P

I definately can't do any fancy low inverted passes with the AMR until I break the habit of instinctively pushing forward on the stick a little while inverted.
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