Platinum Pacer Wings

[mmoyle]

Cool...thanks guys...


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[wyandot jim]

According to AC 43.13, 2 1/2 is the minimum. I prefer 1 1/2 because it seems to prevent issues from arising.

The charts that the covering manuals use for rib stich spacing are from the old CAM 18 and now the AC 43.13 The spacing is defined by the SPEED of the aircraft NOT THE HP.
I used 3" and 1 1/2" on our Pacer it just makes life easier when laying out the chalk lines.
The closer the better in the tank bays works.
I also did the tank bay stitching with the tanks OUT.

[Steve Pierce]

This board was made off factory Super Cub spacing, 1.5" in the tank bay and 3" outboard.
PXL_20210202_210038654.MP.jpg

[Gilbert Pierce]

I used Steve’s board. 1.5 & 3.0 inches.

[mmoyle]

Thanks Steve,
I laid out the bottom then transferred to the top of the wing with a square... that template would make short work of the layout!


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[59pacer]

Your rules there would probably let you go straight to AC43, Chapter 2. The maximum stitch spacing for the wing/ailerons/flaps is determined by Vne, and whether it's in the slipstream or not. For the tail group you can double the spacing. You can reduce the spacing if you wish.
Both the Ceconite and Polyfiber procedure manuals reference AC43.
I'm currently stitching the wings of our son's WWI Albatros fighter. It wasn't a fast aircraft, of course, but the Germans used about 1" spacing, so I have to do the same so it looks a bit authentic. There seems to be millions of knots. They tightly wrapped the ribs with cotton, then sewed the fabric to that with a needle and thread. That's a bit anal, so I'm doing the standard 'hidden' modified seine knot.The lower wing surface being concave complicates the issue. The trailing edge is piano wire. All a learning experience, but then, what else would I do with my time?

[dgapilot]

Thanks Steve,
I laid out the bottom then transferred to the top of the wing with a square... that template would make short work of the layout!


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I always layout on the bottom using a piece of 1/2” wide elastic relaxed, mark corresponding locations at the front and back for alignment. Then pick up the same points on the top and stretch the elastic, then transfer the stitch locations from the elastic to the wing. Works good.


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[dgapilot]

For the past three days I’ve been trying to do what I want...to nasty for aircraft to fly...so... ignore the runway. Spent yesterday repair freeze damage to the schools plumbing... now the maintenance person understand how important keeping the heat on is...

So...question. I’ve been searching for rib stitch spacing dimension. Superflight says 2-1/2” in prop wash areas...I’ve read 2” spacing for 180 hp... then spent time looking through every drawing on the shortwing CD. Two of the drawings indicate 1-1/2”...which is what I’ve laid out.. so...just guessing. Due to the engine downward angle this causes stronger prop pulses hitting the bottom of the wing...if the engine were at zero thrust line...the air wouldn’t pulse or hit the bottom of the wing...it would accelerate and de accelerate as it slipped past the wing... so what changed...why in 1950’s did the drawings call out 1-1/2” and now 2-1/2” is called for in the fabric system manual?


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TriPacer drawing12487 note 4 calls for 1 1/2 spacing on ribs #2 & #3, then 43” spacing for all others.


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[mmoyle]

I went with 1-1/2” and 2-1/2”. The blind stitches between the spar and false spar in the tank bay area were so much fun. Used a very small Crochet hook, 1-1/2” R needed...used backwards. The eye of the need goes through the pre-punched hole first. 50/50 chance of catching the correct lacing thread..

[MrBill]

My biggest gripe about the job is when you finally reach a speed that satisfies your need to be proficient...your done and you'll have to except all that time you wasted at the beginning.