----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
In a message dated 11/1/2006 11:14:51 PM Eastern Standard Time, [EMAIL PROTECTED] writes:
providing references to proper procedures to "keep our aircraft in airworthy condition" as you do - referring to the canopy rigging
Don,
Here are the things that I would be concerned with when inspecting the security of the Alon canopy for flying the plane with the canopy open:
1. The diameter of the nylon canopy rollers should be checked to make sure that they are significantly larger in diameter than the "slot" or opening in the side canopy tracks that they roll in. This will prevent the roller from popping out of the track. Also, when inspecting the rollers, check that they have not worn round on the flat ends. The ends should be square or nearly so in cross section. These rollers do wear over the years.
2. Check the security and condition of the screw that the roller is attached with. There should be a fiberlock nut on the inboard end of the screw. Make sure that the nut is there, that it is tight, and that the threads are sticking out of the nut by one or two threads. If this nut falls off, the screw can work its way out, turning the roller loose, and then the canopy will be free to separate from the fuselage on that side.
3. Check the condition of the aluminum canopy frame where the hole for the above screw is drilled. Make sure that there are no cracks in the aluminum or any other signs of impending failure of the aluminum itself. This aluminum can take a beating if people grab the canopy frame to hoist themselves up on the wing, because when the canopy is forced aft, the thing that stops it is the rollers stopping on the phenolic blocks. This tends to impart a twisting or bending moment on the aluminum frame around the screw. If a lot of force is applied, it can bend the aluminum around the roller screw.
4. Make sure that the phenolic blocks inside the side canopy tracks are there, and that they are in good shape, and that the screws and nuts that hold them in place are tight and in good shape. These blocks stop the canopy from traveling too far aft. As you know, the slots in the side canopy tracks are cut out large enough for the rollers to pass through them at the extreme aft end so that the canopy can be removed after these phenolic blocks are removed. If you have one of these blocks come loose, that side of the canopy may be able to move back to a position where the roller can come out of the track. The two screws that hold these blocks see a lot of stress because every time you latch the canopy from the inside, these screws are "pulled forward" and every time the canopy rollers hit the phenolic blocks, these screws are "pushed backward". Adding to this problem is that fact that the screws pass through the plastic arm rest material, so they probably are not maintaining much, if any, torque, so the screws are probably able to move back and forth slightly in the holes when the canopy is pushed back and when it is latched from the inside. If the screws are moving in the holes, they are wearing in the holes.
5. Inspect the aft canopy track and slide block to make sure that the nylon part of the slide block is in good shape and firmly attached. The slide block should be large enough so that it can't come out of the aft canopy track.
6. Inspect the condition of the tracks themselves for any wear that would open the canopy track slots up more than they should be.
If all of these items are in good shape, the canopy should not come off in flight. Like Ralph said, it was designed to be able to be open in flight. If everything is as it should be, it should be safe enough. Having said all that, I personally don't trust it and that is one of the reasons that I don't like flying with the canopy open. But that's just me, and I tend to be overly conservative about anything that might prevent me from flying again tomorrow.
Best Regards,
Wayne DelRossi
Alon N5618F
Hours logged since restoration: 187.3
Wayne DelRossi
Alon N5618F
Hours logged since restoration: 187.3
============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm
