Trammeling- How to adjust drag wires to make spar straight

[Daveembry]

OK loosen that x until you get half of the bow out. Then take up tension in the X beside it. When you loosen it, the others will loosen slightly too. Only tighten the ones that got looser in the other bay. Loosen as required as you tighten the ones on the bay beside until you have it straighter and all tensions the same. See how that works. That X is pulling the spar on you. As you loosen and tighten watch how the spar moves. Keep the string line on it. The tightens of all wires effect every other wire. Hope that makes sense? I might be wrong, but it is easier than starting from scratch

OK. thanks. Will give it a shot. I did loosen that X before and of course, that just lowered the pull on those wires in that bay but I didn't think to take up that slack in the bordering bays. Makes sense. Now off to play some more! Thanks again.

[Daveembry]

OK. thanks. Will give it a shot. I did loosen that X before and of course, that just lowered the pull on those wires in that bay but I didn't think to take up that slack in the bordering bays. Makes sense. Now off to play some more! Thanks again.

OK. I had a call into Mitch and he called as he is driving to Oshkosh and gave me these tips:

1. Loosen all wires SO THAT THERE IS AT LEAST 1" OF FREE TRAVEL OF ALL THE WIRES IN THE WING (not just "loose"...but 1" at least of free travel) and leave them all that loose except for the 2 wires that you work with at a time in each bay!
2. Stringline the spars and MAKE THEM STRAIGHT ON THE STRINGLINE (just manually move them in and out until it lines up with the stringline. Just "physically" do this with your hands and not using drag wires) BEFORE YOU START AND KEEP IT THAT WAY AS YOU WORK FROM BAY TO BAY.
3. Square the #2 tube by physically moving the spars in and out (left or right) while the square ia on that spar and tube. Don't adjust yet with the wires. Get the front and rear spar square with the #2 tube by physically moving the spars in one direction or the other.
4. Tighten nuts on both big and small wire where they come out at rib #1 until you have EXACTLY 1" and leave these set here and not move them again. (Because later you will have to remove these wires to install the fuel tanks and you will simply reinstall them and tighten them so that the 1" is there and you will have it exactly back where it was without having to measure it later.
5. Begin tightening the 2 wires going into the first bay (fuel tank bay). DO NOT HAND TIGHTEN ANY OTHER WIRES IN THE WING YET SO YOU CAN MOVE THE SPARS AROUND AS YOU MOVE DOWN THE WING. Note that the big wire is a different thread than the small one, so tighten the small wire a 1/2 turn and then move the big wire only say 3/8 of a turn so they are actually tightening about the same amount. Keep checking the square of the #2 tube as you go and when you have 13-15 lbs at the center after 1/2" of travel, you are done. Check the square again.

NOTE: ONCE YOU HAVE FINISHED A BAY AND THE NUTS TIGHTENED DOWN AND YOU HAVE THE RIGHT AMOUNT OF PULL ON THE WIRE, THIS BAY IS SET AND WILL STAY THIS WAY AND IS UNAFFECTED BY THE BAYS AFTER THIS (AS YOU MOVE OUTBOARD ON THE WING.) SO ANY ADJUSTMENTS YOU DO AFTER THIS BAY ON OTHER BAYS, WILL NOT AFFECT THIS ONE. (So don't adjust anything in this bay again.)

6. Before you start tightening the next bay in line (going outboard), first physically align the spars with your stringline and then begin tighening the drag wires again until you have your correct tension. Again, by "physically", I mean take your hands and just push/pull the spar until it aligns with the string as you want it. It will easily move as long as you have LOTS of slack in all the rest of the drag wires.

You only need to measure 1 of the small wires in the last 2 bays (the 2 outboard bays that only have small wires) and only the small wire in the first 2 bays (that also have a big wire) because they will both be the same.

You do not have to check the square of the #2 compression tube after you do the first bay. Once it's squared the first time, it will stay square since no further bays will affect this bay once you have finished. Mitch said the importance of the #2 compression tube being square is that it will set the wing attach points so when you go to install the wing, it will all line up correctly. The importance of course for the rear spar to be perfectly straight, is so the flaps/ailerons to fit correctly.

When I did it this way, it all worked out perfectly and was very simple actually. My mistakes were:

1. Not having LOTS (1" or more) slack in all the drag wires. I had them "loose" but not THAT loose. Having them really loose lets you move the spars all around like you want them to get them in line
2. Going back and forth between bays making adjustments. Start inboard and move outboard and once one bay is done, don't touch it again.

Hope this helps and thanks for the help.

[c130jake]

Much better explanation than mine. Your post should be in the next manual change. I guess I should have said how loose.

Jake

Sent from my SM-G930V using Tapatalk

[Daveembry]

Much better explanation than mine. Your post should be in the next manual change. I guess I should have said how loose.

Jake

Sent from my SM-G930V using Tapatalk

Yes, sometimes the manual needs a little more details for the inexperienced (like me!). I had them "loose".....just not loose enough (all the drag wires) and I didn't know you could essentially "manhandle" the wing to get it in the right position before you even started tightening the drag wires. Done that way it didn't take me 30 minutes to do it. Nice to know for the 2nd wing.

[David H]

Dave,
Thanks for the thorough and complete write up. Very helpful. I am at that stage now.
Yes, this write up should go in the manual update.
Keep up the great write ups!
David

[aeroaddict]

Wow! Just finished the second wing and had it done within an hour. Certainly NOT like the first wing!

It went so smooth that I double/triple checked everything just to make sure I hadn't missed something. I think the key part here is: "Before you start tightening the next bay in line (going outboard), first physically align the spars with your stringline".


Cheers,
Dan

[Daveembry]

Wow! Just finished the second wing and had it done within an hour. Certainly NOT like the first wing!

It went so smooth that I double/triple checked everything just to make sure I hadn't missed something. I think the key part here is: "Before you start tightening the next bay in line (going outboard), first physically align the spars with your stringline".


Cheers,
Dan

Great! Glad it helped. After speaking with Mitch, it all worked easy! (Just wish it had been in the manual that way to start with.)

[David H]

Dave,
Thanks again for the write up. I just trammeled my first wing in ~ one hour. It is now perfect. Manual says to rivet on two nose ribs and then there is no guide string used on the front spar. Hmmm.
For me, it seamed that I tightened the big wires in bays one and two just a bit past finger tight and then tightened the small wires from there to get the 13 -15lb pull. When I tightened both big and little equally for the initial tightening, that threw things off, especially in bay two. That means loosen everything a lot and start over.
David

[Daveembry]

Dave,
Thanks again for the write up. I just trammeled my first wing in ~ one hour. It is now perfect. Manual says to rivet on two nose ribs and then there is no guide string used on the front spar. Hmmm.
For me, it seamed that I tightened the big wires in bays one and two just a bit past finger tight and then tightened the small wires from there to get the 13 -15lb pull. When I tightened both big and little equally for the initial tightening, that threw things off, especially in bay two. That means loosen everything a lot and start over.
David

David, that's great! Glad that helped.

One thing that Mitch did say is that the thread is coarse on the big drag wires and fine on the small wires, so you REALLY can't tighen each 1/2 turn each time (no mention of that in the manual either) so you REALLY just tighten the big wire less than 1/2 turn. What I did was to get it perfectly straight (rear spar stringline) and then I tightened the small wire the 1/2 turn and the big wire maybe 3/8 turn and then checked it again. Once I did that and saw if it was getting off a bit, I would back off the big wire until it was square again. It probably worked out to be about a little over 1/4 turn on the big wire.

I ask Mitch also why the manual said to put a stringline on the front spar and then says "the rear spar must be perfectly straight". I ran one on the front and back and of course, they stayed in or out equally anyway. As long as the compression tube are tight against the spars, it doesn't matter I don't guess which spar you stringline. Just measure first the distance between the spars at each compression tube and they should be dead nuts on before you start. Mine was within 1/32" the same!

Just finished my 2nd wing except for a few rivets that I was short that Mitch is sending. Amazing the difference in time between trying to figure out what I was doing on the first wing to running through the 2nd.

Left Wing - 83 hours
Right Wing - 53 hours

This was time just spent in the garage actually working on the wing which also included following along in the manual, looking at photos, etc. It didn't include all the hours of reading the manual and watching videos prior to getting the kit.

Looking forward to starting the fuselage.

[garick]

I am a new EX-3 builder and have watched the Dave E. video, the forums, and read the instructions. I have spent a couple of hours the past few weeknights and still can't figure out trammeling. I can square the #2 tube and then I move to the next bay. As I adjust the next set of drag wires tube #2 comes out of square. I tried going down the line in the case of a miracle and adjusting the drag wires bay by bay from inward to outboard but the #2 tube ends up out of square. Any ideas why this is happening?