Originally Posted by solentlife

Any elevator ? Most models except neutral aerobatic jobs of course like a touch of down elevator to track straight in KE ...

Nigel

Yes correct Nigel that's exactly what i was trying to do. On my spectrum DX6i I used a rudder to elevator mix which had a rate of D - 9% U + 5%. So when using the switch it mixed in the elevator.

Millzye

Originally Posted by solentlife

I'm getting old and lazy ... so I'm going to fit a 3 axis in my Badius .. and let that do most of the work !!

Having spent over 40yrs doing it by 'sticks' ... think it's time to let electronics ease my load !! No need to prove to Aerobatic Judges anymore ... now I fly for fun.

Nigel

Nigel, my comment wasn't about if you should do it or not
I was just saying that if you make a proportional rudder deflection based on the aileron movement, and some models need zero aileron deflection to stay in knife edge, your rudder deflection might also be close to zero. in that case it won't work very well. also if for some reason you have to correct the model with some opposite aileron to stay in k. edge, the rudder will even force the nose down.
for that you might need a curve that for example keeps the rudder always positive no matter the side the ailerons go. but then we have 2 problems again. aileron near zero, which you might solve by applying an offset to the rudder, and you will have to have a switch position for left and right knife edge.
of course I didn't test any of this, but it sounds logical to me

Originally Posted by Millzye

Yes correct Nigel that's exactly what i was trying to do. On my spectrum DX6i I used a rudder to elevator mix which had a rate of D - 9% U + 5%. So when using the switch it mixed in the elevator.

Millzye

We're curious as to what your final working setup will be. mixes, etc. Do let us know.

Originally Posted by jhsa

Nigel, my comment wasn't about if you should do it or not

I know ... I was just saying that I'm getting lazy in old age !!

Relax - wasn't getting at you at all or anyone else !



Nigel

For something like knife edge corrections in er9x you simply add a mix line to each channel that needs correction.

So for example elevator would be something like

ch3 100% ELE
+ 5% RUD noTrim curve (|X|)

Then adjust the weight to get the direction and amount of compensation you need.
The |X| part makes the correction the same for both directions of the rudder stick.
You want to use no trim because you don't want changes in rudder trim to move the elevator.

Alternatively you could go through a V-shaped curve if you want to fine tune the response.

Similar lines can be added to your aileron mix(es).

There are ways of assigning the amount of corrections to one of the pots to allow you to tweak the settings in flight, but exactly how depends on which version of the firmware you are running.

If you find you need different amounts of compensation for each direction and don;t want to mess with custom curves then use two lines with the > and < curves

ch3 100% ELE
+5% RUD noTrim Curve (x>0)
-6% RUD noTrim Curve(x<0)

Although a curve is probably the better way to address this.

Pat MacKenzie

I have fun playing with my orx 3 axis stabilizer too. Especially in my SE-5a and Spitfire. Still very curious as to what his settings may be.

Looks like Pat's got it covered. Have fun.

Get the stabilizer, turn it on it's side, swap the ele and rud channels in the mixer (not in the rx) with the same switch you use to turn the stabilizer on, and you will have a controlable stabilized knife edge when you flick that switch.. only when in knife edge mode the 2 channels will be swapped. Not in normal mode.. just fly your plane in knife edge the same way as you fly it normally..
Would this work?

Originally Posted by jhsa

Get the stabilizer, turn it on it's side, swap the ele and rud channels in the mixer (not in the rx) with the same switch you use to turn the stabilizer on, and you will have a controlable stabilized knife edge when you flick that switch.. only when in knife edge mode the 2 channels will be swapped. Not in normal mode.. just fly your plane in knife edge the same way as you fly it normally..
Would this work?

Why ?

Mount the 3-axis as normal ... set-up as normal. Why swap anything ?

If in K-E and it needs down elevator to track straight - the Stab will give elevator command as it detects the model deviating. Similar with any other deviation - it will correct by using the relevant command.

Whether DOWN is on it's side or inverted or what- DOWN = DOWN .... same with the others.

If that isn't true - then you would not be able to use a 3-axis stab in anything except straight, upright level flight.

In fact - you can if set right - do away with mixes to compensate and let the 3-axis do it for you ...

Pls note - I do not know if it is successful ... it may need more fine level of control than it can deliver ... I will find out later when I get home. What I do know is people report rock steady - straight tail-dragger take-offs with them !! That's a bonus to start with !

Nigel

Nigel, you actually just gave me an idea.. I have a modified multiplex pico cub that is a little devil on takeoff. I have one of those heli gyros and I might install it to stabilize the rudder
It is really difficult at the beginning of the TO run. I do love doing touch and go with it, but if I let the speed drop too much after landing, it can just turn in any direction

Originally Posted by jhsa

Nigel, you actually just gave me an idea.. I have a modified multiplex pico cub that is a little devil on takeoff. I have one of those heli gyros and I might install it to stabilize the rudder
It is really difficult at the beginning of the TO run. I do love doing touch and go with it, but if I let the speed drop too much after landing, it can just turn in any direction

If you want to have nightmares on the ground ... get a Nieuport 28 or similar. The prop is only just in front of the wheels and the darned things go all over the shop. I had a Pilot N 28 ... came 8th in Southern UK Scale Comp with it years ago ...
That was one of the worst tracking machines I ever had - great in the air .. but on the ground !!

If only todays Gyro's had been around then ... I could have cured that baby ...

Watch this if you dare !! (Yes that's me 35 odd yrs ago ... with the beard and N28)

Waltham Chase Aeromodellers pt1 + Lee on Solent.wmv (5 min 15 sec)

There's only one area that needs thought ...

When you go into KE .. we have to lift the nose significantly higher than the tail .. so we effectively CRAB the model along holding nose up with rudder ... the gyro doesn't know that and will initially take a level attitude and if we do not lift the nose ... gyro will happily keep nose / fuselage straight but trajectory will be curved into the ground. In my mind that means the gyro will only cover the KE once we have set it initially manually .. the gyro will follow our corrections till we have it set ...

No need to switch on / off gyro .. it's just that initial few secs when we pull her over into KE and get her tracking .. we cannot let the gyro take over till model is steady on the KE.

I hope people can understand what I'm trying to say ... difficult to put in words !!

So maybe the mix is not such a bad idea to use in conjunction with the 3-axis ...

Nigel

Nice video. The plane was really difficult to control on TO. Worse than my pico cub.

Originally Posted by solentlife

When you go into KE .. we have to lift the nose significantly higher than the tail .. so we effectively CRAB the model along holding nose up with rudder ... the gyro doesn't know that and will initially take a level attitude and if we do not lift the nose ... gyro will happily keep nose / fuselage straight but trajectory will be curved into the ground. In my mind that means the gyro will only cover the KE once we have set it initially manually .. the gyro will follow our corrections till we have it set ...

I'm a bit ignorant wrt 3-axis stabs, but could you not just put the plane into KE and retain control of just the rudder/throttle, letting the stab take care of ele/ail? let go of the right stick (mode2) altogether initially, then once required attitude is obtained, control throttle only. sounds simple enough to me. could be wrong, I'm just thinking logically.

Originally Posted by ukbren

I'm a bit ignorant wrt 3-axis stabs, but could you not just put the plane into KE and retain control of just the rudder/throttle, letting the stab take care of ele/ail? let go of the right stick (mode2) altogether initially, then once required attitude is obtained, control throttle only. sounds simple enough to me. could be wrong, I'm just thinking logically.

Correct and is agreeing with what I said ...

Rudder keeping the nose up ... gyro then doing this for you ...

The other controls - Ele / Ail are not basically going out of true .. so they will act fine from initial point.

The question is : Will the Or 3-axis stab be good enough to actually do it ? The amount of rudder needed for most models to maintain KE is considerable ... it's only aerobatic jobs that usually can KE loop or use less rudder for sustained KE.

But anyway - I apologise to 9xr people here ... I've wandered of topic .. sorry.

Nigel

That is programming. Not off topic in my opinion..

Originally Posted by solentlife

But anyway - I apologise to 9xr people here ... I've wandered of topic .. sorry.

Nigel

I think it's pretty interesting, as it seems it will affect your radio mix as well?

Future judges will ask you to present your stabilizer code and Tx mixes as part of the competition!