The article of the rotated front wing clevis and associated photos are quite disturbing especially considering that the ends of the sheared rivets (if sheared by rotataion how can two of the six shear and not shear the other four?) are still in place. This makes an inspection useless because all appears correct so it's like crossing your fingers and hopeing for the best. Is there any other instances like this?
Russell
Pilots Log
by flyalaz » Mon Oct 24, 2005 3:32 pm
Hi Russell,
The upper four remaining rivets are only common to the wing attachment plates and associated spacers. When the three rivets on each side of the centre bolt sheared, in allowed the entire clevis assembly (wing attachment plates) to rotate on the control support tube attachment bracket, which is attached to the fuselage tube end cap with the bottom six rivets as well as the six sheared rivets and centre bolt.
Maybe someone out there knows if there were any other incidents of this type. I only know of this one, and it was enough to make me do the mod. It was already apart, and two bolts for peace of mind was a cheap price to pay. My other Lazair does not have this mod done to it, and I still have full confidence in the design. I will never make that type of mod (third engine) to my plane, and am content to fly it in the envelope it came in!
Cheers,
Karl
The upper four remaining rivets are only common to the wing attachment plates and associated spacers. When the three rivets on each side of the centre bolt sheared, in allowed the entire clevis assembly (wing attachment plates) to rotate on the control support tube attachment bracket, which is attached to the fuselage tube end cap with the bottom six rivets as well as the six sheared rivets and centre bolt.
Maybe someone out there knows if there were any other incidents of this type. I only know of this one, and it was enough to make me do the mod. It was already apart, and two bolts for peace of mind was a cheap price to pay. My other Lazair does not have this mod done to it, and I still have full confidence in the design. I will never make that type of mod (third engine) to my plane, and am content to fly it in the envelope it came in!
Cheers,
Karl
-
flyalaz - LazairNUT
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by russell » Mon Oct 24, 2005 4:12 pm
Karl,
I too fly with great respect for the integrity of the Lazair. I know that it was designed to be strong but I am aware that if flown outside of it's design envelope one is taking a risk of failure. I have never stressed my plane while flying. As everyone is aware the most stress can be applied while simply handling or assemblying. From the article it appears that this failure occured because of an error in assembly prior to flight. I do a thorough walkaround before each flight but this structural damage in the article is not apparent in any way. I like your modification with the extra bolts, however, Dale's words keep ringing in my ears. He has always stressed never to drill a hole in anything, anywhere unless you understand the structural engineering of the plane. So, because of my ignorance in this I could never bring myself to make any modifications.
Should you hear of any problems anyone else has had with this piece please post them.
Thanks,
Russell
I too fly with great respect for the integrity of the Lazair. I know that it was designed to be strong but I am aware that if flown outside of it's design envelope one is taking a risk of failure. I have never stressed my plane while flying. As everyone is aware the most stress can be applied while simply handling or assemblying. From the article it appears that this failure occured because of an error in assembly prior to flight. I do a thorough walkaround before each flight but this structural damage in the article is not apparent in any way. I like your modification with the extra bolts, however, Dale's words keep ringing in my ears. He has always stressed never to drill a hole in anything, anywhere unless you understand the structural engineering of the plane. So, because of my ignorance in this I could never bring myself to make any modifications.
Should you hear of any problems anyone else has had with this piece please post them.
Thanks,
Russell
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- LazairNUT
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