John B Posted July 11, 2012 Author Report Share Posted July 11, 2012 (edited) Hello all. I am part owner of a Sperber RF5B. Because of our poor weather, business commitments and my laziness she hasn't flown for over eight months. Working through her Annual check to get her back on line we have found that the left spoiler is reluctant to deploy fully. The right side deploys cleanly, the left one only half to two thirds. It can be pulled out fully, but feels quite stiff. The only good look I can get at the spoiler torsion rod is at the underside access plate for the aileron rod connection near the pitot head attachment. It looks as if there may possibly be some excess grease or lanolin on the torsion rod, possibly helping to cause drag at the rib penetrations, however that is all. I shall clean that up of course.The parts diagram doesn't show any bushings holding the rod in place, though I presume there are some - it surely can't just be rotating in holes through the ribs. I suspect that a soaking last year and the very damp weather over the past few months may have aided corrosion on the spoiler plate hinges. I can't get any view of these, but could spray some thin oil in on general principles. I'm a little reluctant to do that blindly, since oil soaking wood is a bad idea. It is also possible that damp may have swollen the rib wood, squeezing the spoiler box penetration points.It seems to me that the only way to inspect and rectify in this area is by cutting away fabric on the underside of the wing, which I should be able to do carefully and repair readily. Does anybody have any comments or any experience in this which might help me please? It seems unlikely I am the first person to encounter this snag.Any comment or help will be most welcome. Thanks,John Bisset Edited July 12, 2012 by John B Quote Link to comment Share on other sites More sharing options...
John B Posted July 11, 2012 Report Share Posted July 11, 2012 (edited) Hello all. I am part owner of a Sperber RF5B. Because of our poor weather, business commitments and my laziness she hasn't flown for over eight months. Working through her Annual check to get her back on line we have found that the left spoiler is reluctant to deploy fully. The right side deploys cleanly, the left one only half to two thirds. It can be pulled out fully, but feels quite stiff. The only good look I can get at the spoiler torsion rod is at the underside access plate for the aileron rod connection near the pitot head attachment. It looks as if there may possibly be some excess grease or lanolin on the torsion rod, possibly helping to cause drag at the rib penetrations, however that is all. I shall clean that up of course.The parts diagram doesn't show any bushings holding the rod in place, though I presume there are some - it surely can't just be rotating in holes through the ribs. I suspect that a soaking last year and the very damp weather over the past few months may have aided corrosion on the spoiler plate hinges. I can't get any view of these, but could spray some thin oil in on general principles. I'm a little reluctant to do that blindly, since oil soaking wood is a bad idea. It is also possible that damp may have swollen the rib wood, squeezing the spoiler box penetration points.It seems to me that the only way to inspect and rectify in this area is by cutting away fabric on the underside of the wing, which I should be able to do carefully and repair readily. Does anybody have any comments or any experience in this which might help me please? It seems unlikely I am the first person to encounter this snag.Any comment or help will be most welcome. Thanks,John Bisset Edited July 12, 2012 by John B Quote Link to comment Share on other sites More sharing options...
rayjb60 Posted July 11, 2012 Report Share Posted July 11, 2012 John, I'll repost this on the CFI America forum and relay any feedback here Quote Link to comment Share on other sites More sharing options...
rayjb60 Posted July 11, 2012 Report Share Posted July 11, 2012 John, I'll repost this on the CFI America forum and relay any feedback here Quote Link to comment Share on other sites More sharing options...
John B Posted July 11, 2012 Author Report Share Posted July 11, 2012 (edited) Thank you Ray, that would be very kind. I see that site is not accepting any new applications just now, which prevented me from posting there. Regards,John Edited July 11, 2012 by John B Quote Link to comment Share on other sites More sharing options...
John B Posted July 11, 2012 Author Report Share Posted July 11, 2012 (edited) Thank you Ray, that would be very kind. I see that site is not accepting any new applications just now, which prevented me from posting there. Regards,John Edited July 11, 2012 by John B Quote Link to comment Share on other sites More sharing options...
rayjb60 Posted July 11, 2012 Report Share Posted July 11, 2012 John, could you contact Collin at this email as he also has an RF5B and is our US expert on Fourniers.He will also get you set up on the US web forum.collin@techtonicstuning.com Quote Link to comment Share on other sites More sharing options...
rayjb60 Posted July 11, 2012 Report Share Posted July 11, 2012 John, could you contact Collin at this email as he also has an RF5B and is our US expert on Fourniers.He will also get you set up on the US web forum.collin@techtonicstuning.com Quote Link to comment Share on other sites More sharing options...
John B Posted July 17, 2012 Author Report Share Posted July 17, 2012 Hello again all. (This note has also been posted on the CFI America forum.)An update and a couple more questions. When I removed the fabric below my port spoiler box, about 350ml of water flowed out. The area is being dried now. The spoiler torsion rod was well covered with grease, or perhaps lanolin. My aircraft engineer is concerned about possible corrosion of the rod, though I have not seen any so far. He is worried the rod could shear if it has corroded. I am cleaning it down to check and I hope demonstrate it is not significantly corroded. He also wondered whether it would be possible to remove the rod for checking, and to allow easy access to the wooden bushings to dry them out and if need be ream them. There is a hole at the mid-wing fold point which looks as if it may be for this purpose. We are unhappy about trying to release all the spoiler actuating arms. Aluminium clamped to steel may not remove readily after so many years – I have visions of shearing a clamping nut or bolt and having to find replacement spoiler blades. I would rather demonstrate to his satisfaction that the rod is in good condition and would further argue that the spoilers are so relatively ineffective that, even in the highly unlikely event of a rod failure, deployment of only one spoiler will have little effect on flight path. (Speaking as a glider pilot I do not believe I have ever used such an ineffective system as those spoilers – possibly the only feature of the RF5 which I feel is really poor.) I also feel there is unlikely to be enough load on the torsion rod to shear or buckle it, even if significantly corroded.What do others think? Has anyone removed the torsion rod through the mid wing access hole? Are replacement spoiler blades still available? If so, where from? Additionally, does anyone know of a lubricant suitable for wooden bushes? I am minded to leave them dry, though trying to squeeze some graphite powder in might be useful. I still hope continuing to dry things out will solve the problem. Also does anyone know what the material coating the torsion rod is? I thought it might be lanolin? Comments, thoughts, anyone? – all welcome! Thanks,John Bisset Quote Link to comment Share on other sites More sharing options...
John B Posted July 17, 2012 Author Report Share Posted July 17, 2012 Hello again all. (This note has also been posted on the CFI America forum.)An update and a couple more questions. When I removed the fabric below my port spoiler box, about 350ml of water flowed out. The area is being dried now. The spoiler torsion rod was well covered with grease, or perhaps lanolin. My aircraft engineer is concerned about possible corrosion of the rod, though I have not seen any so far. He is worried the rod could shear if it has corroded. I am cleaning it down to check and I hope demonstrate it is not significantly corroded. He also wondered whether it would be possible to remove the rod for checking, and to allow easy access to the wooden bushings to dry them out and if need be ream them. There is a hole at the mid-wing fold point which looks as if it may be for this purpose. We are unhappy about trying to release all the spoiler actuating arms. Aluminium clamped to steel may not remove readily after so many years – I have visions of shearing a clamping nut or bolt and having to find replacement spoiler blades. I would rather demonstrate to his satisfaction that the rod is in good condition and would further argue that the spoilers are so relatively ineffective that, even in the highly unlikely event of a rod failure, deployment of only one spoiler will have little effect on flight path. (Speaking as a glider pilot I do not believe I have ever used such an ineffective system as those spoilers – possibly the only feature of the RF5 which I feel is really poor.) I also feel there is unlikely to be enough load on the torsion rod to shear or buckle it, even if significantly corroded.What do others think? Has anyone removed the torsion rod through the mid wing access hole? Are replacement spoiler blades still available? If so, where from? Additionally, does anyone know of a lubricant suitable for wooden bushes? I am minded to leave them dry, though trying to squeeze some graphite powder in might be useful. I still hope continuing to dry things out will solve the problem. Also does anyone know what the material coating the torsion rod is? I thought it might be lanolin? Comments, thoughts, anyone? – all welcome! Thanks,John Bisset Quote Link to comment Share on other sites More sharing options...
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