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Old February 28th 18, 12:41 PM posted to rec.aviation.soaring
Steve Cameron
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Posts: 9
Default Dg400 rigging tips

On Tuesday, February 27, 2018 at 8:47:49 PM UTC-5, Dirk_PW wrote:
1) Pay attention to how high the main tire is above the ground (while on the cradle) before you start. I noticed that if the tire is less than or equal to 1.5 inches from the ground, wing install goes better. If the fuselage is higher than that (2+ inches), it goes badly. I'm not sure why. I think the extra pitch up attitude of the nose causes a tortional misalignment that requires more force to overcome. I would have thought that once the wings were flush with the fuselage seated in the lift pins then the tortional orientation couldn't be an issue. Anyway, by simply lowering the cradle to get the tire closer to the ground almost always fixed my problem - even though there was no apparent change in the wing gaps and hole alignments.

2) Use your "eyes" to align the spar holes first. If you can 'see' a misalignment, there is no amount of force you can apply to the pin to fix it.

3) If you see a misalignment of the spar holes in the vertical direction (so the assumption here is that the wings are tight against the fuselage and the fore/aft alignment is good), I have found that raising or lowering the CRADLE did a better job of aligning the holes than to raise or lower one of the wings. When you go out to the wing tip and "fix" wing height, you almost always cause the wing to pull out slightly or cause a misalignment fore/aft at the root (so you fixed one problem, but created one or two others).. (This will be less of an issue for you with the electric rigger). However, using the cradle doesn't cause that problem at all, it is the ultimate fine adjustment knob. I like to assemble my wings so that the fuselage is a smidge too high when the wings are in, such that I have to lower the cradle to fix the gap. Because both wing roots are being lowered, gravity is helping keep the wings nice an tight against the fuselage as the cradle lowers. Hope that made sense.


Dirk, thank for yours & others comments, I'll see how thing go this weekend.. I had also gotten into the habit of having the main extended, and very close to the ground, but not touching. Several times yesterday while fighting to get the wings in I noticed the main had lowered to the ground, so it seems I've got a hydraulic foot pump that doesn't quite hold pressure. Because of this it makes sense to me to begin rigging with the fuselage and cradle in its lowest position, so at least I'm starting from a consistent position. I have used self riggers in the past, and a good friend suggested it will take some time to learn the right positioning, etc.
Steve