Fuselage covering question

[BTAZ]

Getting ready to cover the fuselage.

Per the Poly Fiber book, seams which are not sewn need to be over "structure" like a longeron. Their example given is of a Cub and suggested four basic fabric pieces(bottom, two sides, and the top) for the main fuselage and then two pieces for the vertical stabilizer with a sewn seem between these pieces and the top piece.

However, on Eric Newton's's Patrol build site, it appears only three pieces were used(bottom and two sides) with the side pieces meeting at the top stringer and along the vertical stabilizer.

That would seem to be easier but doesn't seem to meet the "approved" Stits method.

Opinions?

[Zac Weidner]

I believe (don't quote me on this) the Shortwings were originally covered in 3 pieces like you mentioned, and I know some have done it that way. When we covered the Tripacer, we did 4 pieces, starting on the bottom panel, and the vertical was separate two pieces with a short baseball stitch right in front of the base of the fin, because of that annotation in the Poly-Fiber manual which you mentioned.


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[Bdflies]

I finished covering my Patrol fuselage, just before heading to Oshkosh. I, too struggled with the decision you've facing. I measured and thought and re-thought my options. Everything kept telling me that the way to do it, was to cover in 3 pieces, splicing on the top stringer. Like you, I have a Stitz book that frowns on such. So, I consulted a friend, who's covered a bunch of planes (and does magnificent work). He took one look, at the aluminum spine stringer and agreed with me that the spine splice is the way to do it. He cautioned me to be careful not to tighten too much and bow the stringer. So, I applied the bottom first. Taughtened to 250. Covered the right side, wrapping the spine stringer. Taughtened the right side - only enough to remove all the wrinkles. Last, I covered the left side, overlapping the top 2" at the spine. Only after everything was taughtened equally, did I start tightening each side, gradually working up to 350. I used a 4" (bias) tape on the spine joint. Worked great!
hope this helps!

Bill

[whee]

It appears you used Stewart's Bill. I recall from the Stewart's videos that their system is the only one that doesn't require the glue joint to be over a structural member. I think they even say that placing a glue seam along a top stringer is an acceptable method. So if your using Stewart's I think your good. If your using a different system then I'd call them and ask.

[Bdflies]

No Stewart's. I used Superflite. I'm aware of the admonition due me, for admitting that I covered this way. I fully expected to catch some flack. If the stringers were wood, I wouldn't even consider such, but those aluminum stringers are pretty tough and the center spine stringer is straight as ever.
I'm not suggesting that anyone haphazardly oppose instructions for an approved system. The question was ventured and, because I have recent experience with the exact matter queried, I responded, giving some detail about how I did it and the results.
As always, your mileage may vary!

Bill

[jaredyates]

Our 4-place has three pieces, but the two top pieces that run down the stringer are sewn together. What keeps you from doing it this way?

[stinger]

I will now enter my two cents. I covered the bottom first, then I made what I call an "open envelop". I made a pattern leaving 4 inches at the top spine and approx. 4 inches along the bottom longeron for the left side, then duplicating it for the right side. My wife sewed the French seam along the back bone/spine leaving the vertical fabric open just prior to the vertical stabilizer. It was only here that I had to be creative to maintain a smooth transition and wrapping it in the conventional way. This left a nice transition from the fuselage to the vertical without an additional seam. After heat shrinking evenly it looked great, covering the top seam with a 3 inch pinked tape Poly- fiber system. There is no fabric hanging down in the cockpit area. Stinger

[BTAZ]

Thanks for all the inputs!

Interesting differentiation between Stewarts and Stits.with regards to this

Still not certain which way I will go.

The center top stringer is pretty well braced with a standoff on each cross tube as well as each diagnol.

Lack of a sewing machine leaves me with the three piece approach or the four with separate tail pieces.

It appears Eric used the three piece on his Patrol with Stits.

[whee]

Btaz, look up Stewart's fuselage covering video on YouTube. It is pretty good and may answer some of your questions. They demonstrated a 4 piece method with the vertical fin being part of the side pieces.

[N942VT]

Nothing wrong with the four piece method either, easier to deal with smaller pieces and your going to have tapes down the longerons anyway

[BTAZ]

No admonition due anyone.

"Experimental" means there are options not available in the certified world. Utilizing those options comes with the price of research and "risk management/assessment".

The final responsibility(and blame) rests with the builder, not the people who are kind enough to provide the insights.

[whee]

No admonition due anyone.

"Experimental" means there are options not available in the certified world. Utilizing those options comes with the price of research and "risk management/assessment".

The final responsibility(and blame) rests with the builder, not the people who are kind enough to provide the insights.

I completely agree!

[Rollie]

I also did a glue seam down the top stringer. The guy who restores old Champs at the local airport recommended it and said it would be fine and easier than stitching and would look better than having a tape from side to side just forward of the fin. He pointed out that if it were certified this wouldn't be allowed but that it would be the way he would go if he had a choice. So I covered mine with two pieces of fabric, one one each side meeting at the top stringer. Are you supposed to cover the bottom? I'll have to look into that.

[Bdflies]

What a great idea! No bottom!
Alas.. it's too late for me...

Bill

[Rollie]

One of the few deviations from the plans I made was to weld tabs to the longerons to fasten metal belly panels to. It was kind of a pain, but after helping with quite a few annuals on various planes and seeing how nice that option is on the Bellanca Scout, I thought it was worth it. I figured .020 aluminum with minimal paint wouldn't really weigh much different that heavy fabric, which is what I would have used on the belly, by the time you do all the required coats of UV blocking primer and paint. I figure the first time I need access to something way back in the tail or under the floorboards it will be worth the extra work. I'm hoping to keep this plane forever so I thought a couple little mods just for me were in order.

[sbmurphey]

@ Rollie, Any pictures? I was considering metal skin under the tail section behind the last stanchion as you described. Any W/B an issue?

[Rollie]

Here are some pics, The one from the bottom was the final fitting before paint. I haven't put it back on yet since I painted it so no finished pics. The others are with it on the rotisserie when I was making the belly panels. I just curved the metal around the stringers allowing the curved shape to give it some rigidity, except for the most forward one which I bent in the brake to match the stringers and the metal piece where you would attach the front of the bottom fabric to. I'm no engineer so to figure out the spacing for the tabs on the longerons, I looked at the spacing on a Scout and made these closer together. Not all that scientific, but I also used nut plates with #10 screws instead ot the 1/4 turn dzus fasteners that the Scout uses. As for W&B, I haven't gotten that far yet but I don't expect any problems, as the metal should weigh pretty close to primed and painted fabric. Prior to mounting I'll put a thin wx stripping on the sheet metal where it meets the longerons.

[sbmurphey]

Thanks for sharing Rollie, I really like the concept of accessing the tail area for inspection and service.