Cutting band arcs (decals)

Can anyone provide a technique or mathematical formula for determining
the parallel convex and concave arcs of a fuselage band where there is a
taper from one side to the other? It seems like there must be a formula
based on the angle described by the axis and the tangent edge of the
truncated cone matching the band, but I can't figure it out. I know I
could just paint these bands, but there are circumstances where a decal
would be much more convenient.
Mark Schynert
Reply to
Mark Schynert
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The easiest way to do this is to wrap masking tape around the fuselage, sketch in the band(s), remove it and use as a guide for cutting painted decal sheet.
Reply to
Al Superczynski
That's pretty much it. Additionally, I can suggest Bare Metal foil and a permanent marker. Doing the rings around the nose of an Me-163 is also a big pain. I wound up using the foil and some rings of taped paper to mark the pattern. Removed that, measured and cleaned it up with a compass. hth
The Keeper (of too much crap!)
Reply to
Keeper
Thanks guys! A lot simpler than calculations.
Mark Schynert
Reply to
Mark Schynert
You pretty much lost me after "Can"... ( ;-) )
Reply to
Edwin Ross Quantrall
Edwin Ross Quantrall wrote in news: snipped-for-privacy@iquest.net:
Yeah, me too, and I thought I was good at math. Ha! I was thinking that there might be a piece of software that could accomplish it and output to a printer for making a template. Anyone heard of such a thing?
Reply to
TForward
It would have to have values for all the many variables. Just think of all the planes that carried bands then add all the various renditions by various manufacturers. I'm gettin' a headache...
Bill Banaszak, MFE
Reply to
Mad-Modeller
That can be overcome by using more than one piece of tape and/or multiple layers. It doesn't matter how thick the pattern is.
Reply to
Al Superczynski
I'm inclined to think a broad swath of ordinary aluminum foil ought to do as well (Not Bare Metal, as it is thinner and a lot more expensive--I think a thicker guage might be more manageable here.
Mark Schynert
Reply to
Mark Schynert
"Al Superczynski" wrote
Well, I don't know if I agree with that. More layers means more chance that the layers will move relative to each other during removal, cutting, or whatnot. Even a thick single layer is inherently less accurate. If your point in going this route was to improve accuracy, that matters.
KL
Reply to
Kurt Laughlin
Two thin layers laid perpendicularly to each other will work better than a single layer. This assumes a reasonably stretch free tape with strong adhesive. The bias of the two layers will help prevent slippage. Personally I'd probably either just eyeball it with a layer of tape and a scalpel or apply the tape and put the item between poppets aligned with the centerline and use a Sharpie to mark straight lines as I rotate it, then cut the tape.
Reply to
Ron

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