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Old 11-15-2011, 05:07 PM
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LuvBipes
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Default Giant Scale Great Planes Yak 55M repair

Hi folks, I recently repaired the landing gear mounting system and surrounding woodwork on a friend's giant-scale GP Yak 55M and thought you guys might like to see the blow-by-blow.

First the background, my friend had a very heavy set up for the plane due to the original engine selection (O.S. FR7-420 Sirius7)
http://www3.towerhobbies.com/cgi-bin...&I=LXZVB2&P=ML (it's OK, go ahead and drool, I do all the time).
This engine, though lovely, weighs in at 111 ozs, which is easily more than 4 lbs over similar power gas jobs. The all up weight ended up about 7lbs over recommended, because over 2lbs of weight were required in the tail to balance the whole thing.

So picture a blustery day, strong cross-wind landing situation, overweight airplane. On touch down one wheel digs into the soft ground and SNAP out comes the RHS landing gear, bring with it about half of the 9mm plywood mounting plate.

My friend wisely decided to replace the O.S. FR7-420 Sirius7 with a more suitable 50cc class gasser, but got a little lazy and decided to "repair" the landing gear mount by pouring an ounce or two of epoxy and clamping it all back together. Needless to say, 2 flights latter, while taxiing back to the pits, the RHS LG just collapsed...

I offerred to do a proper repair and that's how it ended up in my workshop.

The hardest part was actually cleaning out the results of the the previous "repair" - removing gobs of epoxy and splintered wood, was required before I could assess what I was dealing with.

This is the LG area AFTER clean up. notice half the LG mounting plate is missing.



Some of the side sheeting had been ripped out when the LG collapsed and I need to see what was going on under the LG mounting plate, so I removed a porting of the sheeting which was set aside for reinstallation later.