efish

My Feedback: (5)

Hi, I'm thinking of upgrading my current transmitter because of the programming limitations.

A fellow flyer has an A9 and suggested I consider trying one out.

There are 2 issues I need some clarification on:-

#1 One of my planes has 4 aileron servos (2 aileron servos per wing) I can get this to work on my current transmitter with some convoluted mixing, but I lose the trim in one wing plus the onboard programming for e.g. rudder to aileron mix. Can the A9 support such a setup?

#2 Servo sync/servo grouping. I'm not sure if the A9 has an equivalent feature, but the idea is to be able to do away with either a servo programmer or a matchbox on surfaces which use more than 1 servo (e.g. dual servo elevators) Again, I can work around this with my current transmitter, but I can notice when the travel of the servos are not fully synchronised throughout the movement (and not just at centre/end points).

Thank you.

A.T.

1. Yes.
Aurora A9 - Dual Rates, Cambermix uses and assignments Posts 227 & 249.
Aurora A9 - Flapperon - (2Aile & 2Flap with Flapperon for Scale Beaver).
Aurora A9 - Flap (Landing) Mix see also sailplane below
Aurora A9 - Four Aileron Bipe - Set Up independent Aileron Servos.

2. Yes, if question understood correctly,with P-Mix/separate channel, example:
- Aurora A9 - Trim Twin EP Motors
However, if multiple servos on various surfaces such as rudder, then suggest use of Digital servos with programmer may be easier if number of channels is a problem.
Digital Servo Instruction Videos - Programming with HFP-10

Aurora A9, Spectra Pro & Optima - FAQ & Undocumented Features - Mixes, Setups, Tips. {Individual Links often updated}

Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links

efish

My Feedback: (5)

Thanks so much Alan for the quick, detailed and informative response.

On the first issue, my current transmitter can do quad flaps and 4 independent aileron servo (as on a bipe) without too much of a problem. Evenprogrammed in a crow mix on a quad flap 3D plane once and that was very fun. I was very surprised that it just couldn't do the 2 servo per aileron setup as well. Not sure how the A9 would work with 2 servos pulling on 1 surface your p-mix example is one way. But I guess I'll have to try it out and see what happens.

On the second issue, do I understand you to say that the P-mix setup in effect works as well as the servo sync/servo group functions? Or alternatively that the servo sync/servo group functions do not add anythign to the traditional p-mixes? I've setup many such p-mixes on my current transmitter (without the servo sync/servo group function) before, and while they do get the job done, its not quite completely synchronised for some reason (and yes, the mechanical setups are identical).

I only use digital servos for these applciations.

Thank you again.

MikeMayberry

My Feedback: (1)

Plucked from another forum.

Mike.

The trick is to get the linkage as close as possible mechanically before making changes in the radio.

Set up the two channels for one wing as both aile or ail2 and set up both with equal EPA and subtrim. Hook up one servo to the aileron and get that channel all adjusted. Then adjust the other servo's linkage to be as close to perfect as possible. It may be necessary to use a little subtrim adjustment on the second servo to get the arm exactly parallel to the first one. Measure the control horns to be sure they are exactly the same length.

Now you should be able to hook up the second servo (at neutral) without any binding. Wiggle the linkage to be sure it's loose when at neutral, and no humming from the servos. Move the stick a little in each direction and check for binding, adjust epa as necessary. It should not take much adjustment, again get it as close as you can mechanically then do the final adjustments in the radio and it will work fine.

TF
__________________
Tom Fawcett
Wild Hare R/C
http://www.wildharerc.com

efish

My Feedback: (5)

Thanks Tom. I actually read those instructions on that other forum some time ago. They're great and yes, I've been doing just that in accordance with basic setup principles (linkages mechanically correct, minimise subtrim and EPA variance).

No problems with centering or end points. There's absolutely no humming with either servo. My first issue was that my current transmitter doesn't support trimming or the onboard mixes on both ailerons when running this 4 servo configuration. I'm guessing the A9 does.

The second issue is a little more subtle and not unique to the ailerons. I notice with my dual servo elevator setups, the 2 elevator halves are sometimes just a hair out of sync in certain parts of the travel. The center and end-points are perfect. Mechanically, they're setup identicall and sub trim is minimal or zero. Just wondering if the new (?) servo sync/servo group feature will solve this.

Thanks.

MikeMayberry

My Feedback: (1)

There is no specific servo sync/group feature. The servos are just assigned to the channels. Keeping then in consecutive channels is not a bad idea though.

Again... I grabed Toms post on this subject off another forum... Here was a follow up post:



Make sure the angles and lengths are the same (servo arms equal, control horns equal). Many ARFs have fixed horns so that's not a question, others are adjustable length which is easy to measure.

Use identical servos and servo arms and make the angle at neutral the same and you are well on the way. As a practical matter on every plane that I have ever owned this is really close enough and you can use a Y cable without a problem. I've even used different servos on the same surface, as long as their speeds are close to the same and travel is the same it will work fine.

Here's the thing. In most cases the aileron control horns are 12-24 inches apart, and there is enough flex in the aileron that a tiny mismatch will not even be noticed when flying.

Think about it like this. What would you worry about if you only had one servo on the wing and it was way off towards one end? You'd think that aileron is going to twist when deflected.

Well then the other servo will be loaded anyway. so what's the difference if there's a tiny mismatch at full travel, the servo loading will be the same as if it was set up perfectly.

And here's the other thing. Ailerons are rarely used at full deflection, and if they are fully deflected how long can you hold it that way? A few seconds maybe?

Get it close mechanically and you don't even need to match them electronically, just make sure that at center there is no binding. Because that's where the aileron stays 99% of the time.

TF

efish

My Feedback: (5)

Hi Mike, that's useful info too...

Perhaps I am looking a little too closely at these things and just need to lighten up and fly more!

Thanks again.

TigerI

Anyone have any suggestions on how to set up my switches & mixing for my Super Cub & Apprentice. New to RC airplanes & am a little lost as to just what I need to fly them.