On 08/15/2011 08:56 PM, zwakie wrote:
> I do however have one issue: when engaging the servo, the servo
> immediately gives me full left aileron. This exact same thing
> happened with the Navaid controlhead
You forgot to mention whether this occured during flight or at the ground.
At the ground this is easy to occur, the autopilot tries to level the
plane (to what it *thinks* is level) or correct the assumed "heading",
the airplane doesn't responsd, so the autopilot corrects a bit more,
still no response, so it commands an even more aggressive aileron
deflection, etc. This is what you want it to do when turbulence or
whatever requires more aileron deflection to correct the situation. But
on the ground it just looks as if the autopilot commands full aileron
just out of the blue, but this is only because the aircraft behaves very
unresponsive, to say the least. I have seen this behaviour on the ground
too, but in flight it works perfectly.
If this is the case, you should be able to offset the center position in
the autopilot menu (without a GPS connected of course!)
If this happens in flight (or on the ground it looks like it is really
stuck without GPS input and regardless of center settings) I would
suspect the servo is broken.
Without valid PWM input the servo should not engage at all.
I assume that you have carefully inspected the physical rigging and made
sure the servo and autopilot absolutely agree about what is left and
what is right. You might want to configure the autopilot to "reverse" to
check what happens. Full aileron deflection is what you get if the
autopilot tries to correct something but the servo corrects into the
wrong direction. If you missed this step, this fully explains the odd
behaviour of your setup.
> A) my Navaid servo is not properly functioning; Trio has offered to
> look at the servo after I ship itto them (excellent service from
> Jerry!) B) the PWM wire running from the controlhead to the servo has
> broke
If you take out the servo anyway, I would connect it to the autopilot
module on the bench and see what happens. You can even tilt the
autopilot and see how the servo responses. No need to send it to Jerry.
> My question to the list: would a broken PWN wire indeed result in a
> full aileron deflection?
I'm not sure about the navaid servo, but the trio-servo disengages
immediately if it detects something wrong. If the navaid simply gives
full aileron deflection when one wire breaks, I wouldn't even want to
fly with it. I must assume that it disengages too if the PWM signal is
entirely missing.
Frans
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