anyone built the new Spirit of St. Louis

There is a nice article here:

ISTR an article a LONG time ago about someone building an NYP model, don't remember scale or media or anything, but their solution to the swirls was a pencil eraser in a drill after the cowl was painted.

Funny.....that has always been my first suggestion (actually, a sharpened eraser in a rotary draftsman's electrical eraser)....but I figured the idea was too "gonzo" to mention.

:o)

...and I'd sheet the area with foil.

That's close. I used a portion of a mechanical pencil eraser (Pentel I think) that I CA'd onto the end of a piece of sprue about 1/8" dia. I chucked the piece of sprue into a Dremel tool and turned the eraser down to the sprue diameter by passing it over a coarse sanding stick. The resulting tool is an eraser about 1/8" diameter. If you are careful you can spot-face a decent pattern on a foil covered NYP cowling. I kept the working surface of the eraser flat. No abrasive is required. The pattern that results in the foil is delicate so care must be taken when brushing off the resulting Al oxide (?) residue.

MB

Not too "gonzo" at all. Many years ago (more than I care to admit to) I saw that Revell 1/28 scale Sopwith Camel at an IPMS regional and the gent who built it had done the cowling and side panels as machine turned aluminum. That was the method he used, a draftsmen's electrical eraser with a pointed insert. Looked terrific.

Bill Shuey

This depends a LOT on scale. If one is doing the big Guillow kit, a pencil eraser may make sense. But that is too large for a 1/72 or 1/48 model. It would be a bear to come up with something appropriate in that scale

Not really. The basic eraser is 1/4" in diameter, but you can use an exacto to sharpen it to a point and get very small swirls. As an aside, I earned my living as a draftsmen and designer for many years and made the acquaintance of the electric eraser professionally. When I first saw one being used my reaction was "How lazy can you get"? But once you tried on it was a revelation what control it gave you. I went out and bought one for use at home. Then they invented computer drafting--- :-)

Bill Shuey

Not really. The basic eraser is 1/4" in diameter, but you can use an exacto to sharpen it to a point and get very small swirls. As an aside, I earned my living as a draftsmen and designer for many years and made the acquaintance of the electric eraser professionally. When I first saw one being used my reaction was "How lazy can you get"? But once you tried on it was a revelation what control it gave you. I went out and bought one for use at home. Then they invented computer drafting--- :-)

Bill Shuey

"William H. Shuey" wrote in news: snipped-for-privacy@starpower.net:

Any body know why they "whirled" the original sheet metal on the NYP? Did/does it have any mechanical reasons, or just looked good?

Cheers,

Dennis

This used to be a sign of craftsmanship. Originally it was "hand turned". Then they started doing it with machines, and the description was "engine turned".

Originally it was done with a chisel, rotated on a flat machined surface. I can only guess at this, but it would have removed milling machine marks and replaced them with a more attractive pattern.

It was a way for an apprentice to show that he had progressed to a journeyman (not an official test, but to show off and say, hey, I am one of you guys now).

It used to be (actually, probably still is for a really talented master machinist) that one could hand scrape a surface flatter than one could machine it. Hand scraping was a key skill. The hand turning helped demonstrate you had acquired such skills.

So hand turning became a decorative art that was far more easily duplicated with the machine process when that became possible.

ISTR reading that its purpose was to smooth & hide hammer marks. During a time before presses & dies, concave or convex surfaces were shaped with ball-pien hammers & such.

"frank" wrote in news:1140449754.264413.240090 @g44g2000cwa.googlegroups.com:

I asked because I have made a copy of an engine cowling for our museum. It was for a WWI fokker and had it had the swirled finish. I used My English wheel to smoothen the thing and used a steel wire brush in an electric drill to get the swirls on. I was rather proud of my self with the finish, but now I know it was originally done with a chisel, I see my method was just cosmetically correct.

Dennis

I was thinking that in the movie "The Spirit of St. Louis", they used a wire brush in a drill press to do the swirls. But, it WAS just a movie.

me-me wrote:

This does not apply to machined surfaces where the physical purpose it lubricant retention, it later became decorative.

That makes more sense than any other "theory" I have heard. I had read (somewhere...) that such a surface was an aid, in the "anti-icing arena" (gee...that sounds like a place where Politically-Correct hockey games would be played), but if so....somebody please explain the physics...

I don't think it had anything to do with lubrication retention on the Spirit either. :)