FlyingGiants - View Single Post - Precision Aerobatics Extra 260 problems??

Jag01 · 08-11-2009, 10:51 PM

Funny I just stumble across this thread as I have been fighting a battle with this very same plane for sometime with the same issues.

Mine would wing rock in upright harrier and yet be rock solid in inverted harrier. Mine too was carrying a good 2.5mm (on the elevator) of down trim to maintain level flight and a vertical power off down line. I would pull to the wheel in knife edge (again little wonder with that much down elevator mixed in). The plane could be trimmed and cg adjusted to fly straight however it always felt to me that the airframe was fighting against all of the mixes and trim issues and that it was draggy as a result.

I checked incidences and this revealed a lot to me. The tail plane was not warped yet when checking incidence in relation to the main wing, one wing was +1 3/4 the other was +3/4. Ideally incidences should have been checked in relation to the canopy rails, however given the tail plane is glued in it becomes too difficult to adjust the incidence of the tail plane.

I elected to adjust the main wing I made some modification to the fuse to allow me to reposition the wing to change the incidences.

I would love to be able to say that my adjustments solved my problems, however unfortunately I never really managed to find out for real as on the test flight after adjustment the plane went "off air" and ended up a total write off.

I will say this though that immediately upon take off I pointed the nose vertical and with zero elevator trim if climbed dead straight for the first time in its life!, I then pointed the nose down in a vertical power off dive and it tracked straight down with zero elevator input or trim, again it had never been able to do this previously. Unfortunately this was the moment it decided to go "off air" and I could not pull out of the dive. So that abruptly ended my flight testing.

I do not believe the short coupling of this plane should cause the wing rock, I do believe there is an incidence issue with this aircraft that needs to be addressed. I have spoken at length with the designer who insist that their quality control during manufacture would illiminate this possibility.

cheers,

Jeff

08-11-2009, 10:51 PM	#6
Jag01 Bad-ass Super Contributer! Join Date: May 2007 Location: Perth Posts: 395	Re: Precision Aerobatics Extra 260 problems?? Funny I just stumble across this thread as I have been fighting a battle with this very same plane for sometime with the same issues. Mine would wing rock in upright harrier and yet be rock solid in inverted harrier. Mine too was carrying a good 2.5mm (on the elevator) of down trim to maintain level flight and a vertical power off down line. I would pull to the wheel in knife edge (again little wonder with that much down elevator mixed in). The plane could be trimmed and cg adjusted to fly straight however it always felt to me that the airframe was fighting against all of the mixes and trim issues and that it was draggy as a result. I checked incidences and this revealed a lot to me. The tail plane was not warped yet when checking incidence in relation to the main wing, one wing was +1 3/4 the other was +3/4. Ideally incidences should have been checked in relation to the canopy rails, however given the tail plane is glued in it becomes too difficult to adjust the incidence of the tail plane. I elected to adjust the main wing I made some modification to the fuse to allow me to reposition the wing to change the incidences. I would love to be able to say that my adjustments solved my problems, however unfortunately I never really managed to find out for real as on the test flight after adjustment the plane went "off air" and ended up a total write off. I will say this though that immediately upon take off I pointed the nose vertical and with zero elevator trim if climbed dead straight for the first time in its life!, I then pointed the nose down in a vertical power off dive and it tracked straight down with zero elevator input or trim, again it had never been able to do this previously. Unfortunately this was the moment it decided to go "off air" and I could not pull out of the dive. So that abruptly ended my flight testing. I do not believe the short coupling of this plane should cause the wing rock, I do believe there is an incidence issue with this aircraft that needs to be addressed. I have spoken at length with the designer who insist that their quality control during manufacture would illiminate this possibility. cheers, Jeff Last edited by Jag01; 08-13-2009 at 03:19 AM.