E.T.s SKYWALKER 1900...Coupled Aileron and Rudder.

[English Turbines]

Skywalker 1900...Coupled Aileron and Rudder.

Today, because it was pretty calm, I decided to take the SW 1900 out again to see if I could improve the way it flies. The last time out seemed like hard work because apart from getting it trimmed etc it left me thinking I had got something set up really badly.
  Armed with two 10 amp 4S Lipos today meant I could spend some time flying round while I decided what I was doing wrong. After a 25 minute flight and about 30kms later with only half the Lipo used, I landed it, still not happy with how it was flying because this big pussy cat of a plane was proving to be just plain hard work.
   Definitely not underpowered, it can take off easily on just half throttle or less and glide around motor off too. So I decided to keep flying it in manual while I decided what to do about it.
   My next move was to set up a Mixer (On a switch) using Ailerons as Master and slaving the rudder.  So, takeoff uncoupled, (To allow Rudder only)  and then switch in the mixer once off the deck (Flying in Manual of course)
  What a difference, now I could fly around using just Aileron and elevator and the SW was making nice coordinated turns, even small corrections were far more positive. By the end of the 2nd Lipo, I was cruising round the field just 5 or 6 metres up in complete confidence.
  I still need to play with the Storms trims and giro level, but Im not sure now its ever going to truly fly this plane properly as it has no Rudder gyro.

PA Mode.

   Putting it in PA Mode keeps the wings level, but it also suffers from directional instability to some degree when in PA Mode, so the heading lock feature just doesn't seem to work as well as it should do. What PA Mode does seem to do is work in pitch as well as roll, which surprised me. So, for example, if you put the plane in a 5 degree shallow dive and then hit PA Mode, the plane keeps diving at a 5 degree angle unless you override it of course. Do it in level cruise flight and it maintains altitude, which is fine, great in fact.
   A brief RTH test saw the plane do a 180 turn ok and start heading home, but it was also heading downwards, so I had to switch it off until I figure out why as Im pretty sure I set it as maintain altitude during RTH.

Comment / help about PA Mode welcome, as Im still trying to figure out exactly how it should work. Without the benefit of a Rudder giro, Im not convinced the Storm will ever fly the SW properly though. Anyone got the same setup?

                   :vulture:               
   
 
 

[FPVSteve]

I have the same issue with my Skywalker Revolution and the only thing that has helped was making sure that I had mechanical aileron differential set up so that it actually made the turns.

I also had to up the pitch gain to prevent it from descending while turning, and limit the maximum bank angle for the same reason.

However in higher winds the plane still struggles to RTH at times because the rudder acts like a weather vane and since it has sooo much authority, it tries to turn the plane in the opposite direction to the ailerons resulting in a sort of crabbing effect - attempting to turn, but carrying on straight.

I love the Skywalker in calm weather but I rarely fly it in the wind as it's a handful - the MT on the other hand just does the job and essentially ignores the wind.

[English Turbines]

I have the same issue with my Skywalker Revolution and the only thing that has helped was making sure that I had mechanical aileron differential set up so that it actually made the turns.

I also had to up the pitch gain to prevent it from descending while turning, and limit the maximum bank angle for the same reason.

However in higher winds the plane still struggles to RTH at times because the rudder acts like a weather vane and since it has sooo much authority, it tries to turn the plane in the opposite direction to the ailerons resulting in a sort of crabbing effect - attempting to turn, but carrying on straight.

I love the Skywalker in calm weather but I rarely fly it in the wind as it's a handful - the MT on the other hand just does the job and essentially ignores the wind.

Hi Steve,
               Ah, yes Aileron differential, forgot about that one...That's more up Aileron throw than down isnt it..? Achieved by setting the servo arms at a bit of an angle when centred I think?
   Yes, about the elevator gain, you may be right, it doesn't seem to compensate very much compared to the Ailerons for example, although they have way more movement on purpose because I anticipated them being rather unresponsive. I will try cranking up the elevator gain too, good idea. TBH, I haven't really played with the gains or bank angles etc yet.
  Good progress today, was making the Ail / Rudder mixer while flying in Manual which has made it so much easier to fly, which is good because PA Mode is really intended as a course keeper when heading out as I understand it.
  I agree though, I think the SW is a light wind machine really, although mine has plenty of power to spare to make headway, so I will reserve judgment until I try it out.
  Do you have the Storm in your Mini Talon then Steve?

                :vulture:
   
 
 
   

[FPVSteve]

Yea, just offset the centres of the servos and you're good to go - make sure you get it the right way around though or you'll turn even less :D

One good thing about the Skywalker in PA mode is you can use the rudder and do completely flat turns as the FC tries to stay level :)

I have a Tornado in both my Skywalker and my Mini Talon, just a Storm with a few extra features really.

[English Turbines]

Yea, just offset the centres of the servos and you're good to go - make sure you get it the right way around though or you'll turn even less :D

One good thing about the Skywalker in PA mode is you can use the rudder and do completely flat turns as the FC tries to stay level :)

I have a Tornado in both my Skywalker and my Mini Talon, just a Storm with a few extra features really.

My SW1900 wont do that flat turn trick, it just wont...Am I right in thinking the Tornado does Vee Tail mixing then on your M.Talon..or have you got both elevator servos on a Y lead.?

         :vulture:

[FPVSteve]

Yea it does the mixing :)

[FPVSteve]

My SW1900 wont do that flat turn trick, it just wont...Am I right in thinking the Tornado does Vee Tail mixing then on your M.Talon..or have you got both elevator servos on a Y lead.?

         :vulture:

You'll probably find you need to up the gains to get it to work (on ailerons)

[English Turbines]

  Yes, thats the difference Steve, the Tornado is a 3 Axis Autopilot, including Rudder....So when it does RTH, no doubt its using Rudder and Aileron in those turns, which is very useful.
  The only way I could get the Storm to do this is Y Lead the Rudder into the Aileron output....I wonder if anyone else has tried that trick..?

     :vulture:

[FPVSteve]

You'd think - but it doesn't have any stability for the yaw axis with the rudder - the only time it does is when the rudder is in "pitch" mode for a v-tail. Otherwise it has no effect in PA mode or anything like that. Believe me I've had these pains myself trying to get the bugger to turn in RTH.

[English Turbines]

You'd think - but it doesn't have any stability for the yaw axis with the rudder - the only time it does is when the rudder is in "pitch" mode for a v-tail. Otherwise it has no effect in PA mode or anything like that. Believe me I've had these pains myself trying to get the bugger to turn in RTH.

Hi Steve,
                  So, its not a 3 axis Autopilot then is it..?...They just added the Rudder so they could add a Vee Tail mixer..?...what a swizz, cheap trick.

     :vulture:

[FPVSteve]

I guess - although it does have Waypoints, Airspeed sensor, Loiter Mode and a lot more customisation in the menus.

[English Turbines]

I guess - although it does have Waypoints, Airspeed sensor, Loiter Mode and a lot more customisation in the menus.

Hi Steve,

  Agreed, yes....and they probably all work really well on a Vee Tail (mixed) plane like the Mini Talon.

  On the Skywalker though as you have discovered, its pants because the Skywalker has all the directional control of a Rudderless Herr Junker when he's tanked up....lol.

                Sorry, but you get what I mean...:)

                       :vulture: