REFLECTOR: Fuselage Leveling

["Benjamin David Cowan" <bdcowan@telepath.com>]

    While my brother was in town this week we decided to level and bondo my fusalage onto sawhorses. Two days ago we laid up 6 plies of triax to form cradles to go between the sawhorses and fuselage. They seem to spread the weight of the thing out across a larger area. Initially the fuselage seemed pretty close to level.. A popsicle stick here and there and it was pretty close. We found that as we shimmed one leg of the sawhorses it'd raise the whole fuselage though.. bringing the other side away from the cradle. So, we bondoed the cradle to the fuselage in a couple places and placed lead shot inside to help hold the fuselage to the cradles and the sawhorses. The cradles had already been bondoed to the sawhorses.

 

Question/Problem:

---Is the fuselage twisted in cases.. Or is it basically straight enough that no twisting is necessary to get side to side leveling without needing to twist it somewhat?

 

The reason I ask this is simple. As we shimmed the sawhorses to move the fuselage side to side aprox 1/4 to 1/2 of a degree we managed to get level readings, really perfect at all the major bulkhead locations,  firewall, canard, inst. panel etc... while at the same time twisting the fuselage. The left cowl back is clearly higher by 1/2" or more than the right cowl back edge. This is clearly due to the fact that shimming a back sawhorse leg on one side raises that side without raising it in the front also,, causing a clear twist in the whole thing.. I thought we had it nailed according to all of the levels.. Then I looked straight back from the nose over my level sitting in firewall position and the left cowl back was sitting much higher.. Anything from the firewall forward will read level.. But as you trail backward of the firewall the twist is apparent.

 

???any observations or suggestions would be greatly appreciated.. My brother says its close enough.. I'm not so sure... My real question is, should a twist even occur in proper leveling? and if so,, should it do that much to the back of the cowl... Putting a level to the back of the cowl, half of the bubble is outside the line..! If on the average, these fuselages are that warped that's one thing.. but my gut tells me that we screwed up..  But the rest is level for and aft and from side to side everything is level from firewall to canard bulkhead..

 

I'm still waiting on hardner and a new pump.. (the old hardner is better replaced.. this was an old kit..) so I have plenty of time with the Christmas season slowing down UPS to do this part right..

 

David Cowan

SW Elite RG