Dg400 rigging tips

Originally Posted by Steve Cameron

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

Hi Steve. With regards to rigging on a cradle with the jack leaking down, it's probably a good idea to leave the wheel up until the wings are on. It also means you can start lower if need be. I do this with my Nimbus 3D, club Duo and various other gliders that have polyhedral. Helps to keep the tip lower as well.

I've heard of fuselages toppling over with a leaking down jack resulting in a broken canopy

I've flown a DG 400 some years ago and loved it

:-) Colin

I have owned a 400 and 808C and would say neither was a
"simple quick" rig.
As others have said, the initial alignment is critical.
DG sell an eccentric aid (nylon/hard plastic) to prevent the first
wing being moved out of position when the second wing is
fitted; this is well worth having; near essential if you are trying
to rig single handed. Any competent machine shop/amateur
could make one to avoid paying DG prices.
You can also buy an eccentric alignment tool (Zulu Glasstek?)
which will pull the two wing together the last few millimetres to
allow the pins to be entered. Again anyone with a lathe could
make one in a few hours from steel round stock.
Without both these aids the 808C was a pain to rig.
The good thing about the 400 is that you have a Rotax engine!

2G had a good comment about marking the spar (to aid with dihedral alignment). After you have successfully assembled the wing and the pins are in place, take a black "Sharpie" pen and scribe a line against the back fuselage to indicate proper rear spar dihedral alignment (right wing), then scribe a line along the intersection of the front and rear spars (on the face of the rear spar) to show proper dihedral alignment of the front spar (left wing) relative to the rear spar. After practice, you will get 98% alignment by just visual cues, then the pap smear technique will get you that last 2%.

My DG-300 sometimes gave me problems early on. What I learned is that the spoiler automatic hook-up can be not properly engaged in the first (right) wing. If that's the case, the spoiler's automatic hookup fitting on the fuselage is not properly aligned to receive the left wing. It will block the wing from coming all the way in.

My procedure is: after getting the right wing seated, I move the spoiler handle while pushing in on the fuselage's left hand spoiler fitting. This allows me to feel when it engages the right hand wing. I can actually open and close the right wing's spoiler when it's engaged all the way.

Larry
FP

You may also want to ask this of the DG Yahoo group. https://groups.yahoo.com/neo/groups/dg_gliders/info.

PS - While I didn't have any issues with rigging my old DG-101, nor did a friend with his old DG-300, that same friend now has issues with getting the main spar pins in on a nearly new DG-303. Sometimes they slip right in, other times it is a hell of a trial. Why? Temperature? Humidity? Phase of the moon? He wishes he knew.

- John Ω

Again, thanks to all for your suggestions. I got the wings & pins in yesterday, and I found particularly effective these two tips: 1-Get one pin partially in and than capture the other, and 2- Raise(or lower) the fuselage to make small, final adjustments in making it all come together.

I worked on a DG-300 that was always a haste to rig. Finally, I removed all lubrication from all 4 lift pins and then painted them black with a magic- marker. Forced the wings onto the lift pins, then slid them out..............magic-marker was removed from the aft side of the aft lift pins and from the forward side of the forward lift pins! Then I jumped on the indicated interference areas with emery cloth cut into 1" strips..............scrubbed them like shining shoes. Took over an hour, but that damned thing finally rigged like it should.
Cheers,
JJ