A helpful step-by-step guide to implementing this undocumented feature of the popular Skysport radio. by Dave Tatosian.
By Dave Tatosian |
How To Program Elevons on the Futaba Skysport 6VA
I have gotten the Futaba SkySport 6VA to support elevons without any add-on
doo-dahs. While you won't find *any* reference to this capability in any of
the documentation for this tx, it is indeed possible.
It should have been obvious but I missed the implications of the
existing mixers: you enable *both* the flaperon mixer *and* elevator->flap
mixing to through the back panel switches, and enable the flaps with the
toggle switch on the top/right of the front. This couples both aileron
and elevator sticks to the same pair of control surfaces. It works
One side effect (that might be a bit disconcerting at first) is you
lose the normal elevator trim to the left of the elevator stick. That
functionality moves to the flap control knob at the top/right of the tx. Might
take a moment to get used to I reckon, but it shouldn't be a major issue...
Anyway, here's the detailed blow-by-blow procedure to setup an elevon
function on the Futaba 6VA SkySport:
- right elevon servo connects to Channel 1
- left elevon servo connects to Channel 6
- on the front upper/right of the tx, set the ELV->FLAP toggle switch
to the On (ie: towards the user) position. Also, rotate the FLAP control
knob to the middle of its range.
- remove the battery compartment panel.
- set the ELV->FLAP switch (Switch 7) to the ON (up) position.
- set the FLAPERON switch (Switch 8) to the ON (up) position.
- it will be helpful to initially set the rate trimmers for both
ailerons and elevators to their full scale positions until after the
next few steps are completed (these are at the far left of the backpanel).
Also make sure that the front panel aileron trim is centered.
- The next couple of steps are dependent on whether the servo reverse
function is enabled for the elevon servos. In my case, with the elevon
control horns on top of the control surfaces, and the servo horns
mounted "in between" the two servos (ala Combat Gremlins), the reverse
switches for both channels 1 and 6 are in the ON (up) position, to
cause the elevon control surfaces to move in the right direction
relative to the aileron stick. In other words, before proceeding, make
sure aileron stick movement is translated into correct control surface
movement (viewed from behind the model!)
OK, onwards we go...
- The ELV->FLAP trimmer in concert with the FLP TRIM trimmer (both at
the right side of the back panel controls) are adjusted to get the
elevons to move in the correct direction when the elevator control
stick is moved. Note that both trimmers have a center "0" position, and
positive and negative ranges on either side of "0". The direction that
you set these trimmers (ie: which side of "0") will depend on whether you
have the servo reversers for channels 1 and 6 enabled or not.
- Per the User's Guide, the ELV->FLAP trimmer sets the direction and rate
of movement for the elevons relative to elevator stick movement. The
FLP TRM trimmer adjusts the flap trimming operation direction and
"variation width" when the flaperon mixing function is enabled.
(yeah, that's a direct quote, and quite a mouthful. Whatever.
Experimentation will shed enough light on what these two trimmers do ;^)
- In my case, with both reversers enabled, the ELV->FLAP trimmer is set
full scale negative, and the FLP TRM trimmer is set slightly negative -
around the "11 o'clock" position. This gets the elevons moving in the
right direction and amount when the elevator control stick is moved off
- Now you can go back and set the rate trimmers for the aileron and
elevator functions. eg: I set the high rates to slightly exceed the
3/8"-per-max-control-deflection recommended for the Combat Gremlin,
and the low rates to slightly below that same spec.
- Note that the front panel elevator trim function moves from the normal
lever to the FLAP control knob once you have elevons set up. And don't
forget that the ELV->FLAP toggle switch *must* be in the ON (towards
the front) position before you launch or you'll have absolutely
NO vertical controls! (ie: the *ultimate* Crash Switch! ;^)
There you go. Again, some experimentation with the use of the backpanel
trimmers will be required to understand their effects. But once you've
got this set up, controlling a "flying wing" is a piece o' cake! And you
won't need to fabricate the sliding-tray rigs or spend another ~$30 for
an add-on mixer.
On that note, once again, a big *Thank You* to the people at Quillen
Engineering (see their ad in the small advertisers section in RCM)
for clueing me into the fact that the 6VA *could* handle elevons (even
though they didn't know the details). They could have just as easily taken
my money for one of their neat PIC mixers, but instead they lent me a
major hand that saved me the time, money, and weight...
Also: if you have the review of the 6VA that was carried in the September
issue of Model Builder magazine (written by Joe Petro, if I have the
name correct), you should be able to find the details on this (and perhaps
worded better, too! ;^) I wasn't able to locate a copy so I had to go
Good luck/Have fun!