How were Fokker Eindecker cowls finished?

[Lufbery]

Hi all,

I've looked at a lot of photos of Fokker E-IIIs lately because I just got the Eduard 1/72 model. The planes' cowls in the photos I've seen look mottled, but it also looks like they are unpainted metal.

So, what caused the mottling on Eindecker cowls?

Thanks,

[tengew]

those were the random swirls from the polishing grinders that were used
it is called juilling

[Lufbery]

Thanks! That's what I was looking for. Here's a little more on the process:

The jeweling process uses an abrasive brush and compound that roughs the metal surface in a circular pattern. If you were to measure the part before and after jeweling, you will discover the finished part is very slightly larger than before it was jeweled. This is because the swirls increased the surface area of the polished metal by raising very tiny serrations. The change is so small that it would have to be measured in microns (much smaller than a thousandth of an inch and not enough to make the part too big), but it does actually get bigger!

Here's a lot more information at this web site.

And here's another web site with some more information.

Naturally, the next question is how I'm going to replicate it at 1/72 scale. I have some ideas, however. Naturally, painting the pattern using a small brush and a darker metallic shade could work pretty well, after some practice. I wonder, though, whether or not it would be possible to actually sand the patterns into the plastic.

Regards,

[SCMc]

Lufbery,

Here is a previous thread on the engine turned cowls of eindeckers.

You can probably find more by searching Fokker E.III in the models section.

I am not sure that sanding the plastic would work. The effect is very subtle, and would be lost when you paint the cowl.

Steve

[Lufbery]

Steve,

Thanks for the link and the additional information. I see now that the engine turning or jeweling is relatively random rather than the more regular patterns seen in the links I provided above.

I agree that painting seems to be my best bet.

Regards,

[JohnFitz]

This is what you want to duplicate.

[JohnFitz]

Oops, sorry for the photo duplication.

[The PIPE]

Dear Fellow Eindecker Fans:

The PIPE Here again...and it's my post at...

Fokker Engine-Turned Cowls

...that shows off the "dragged" engine turning that Tony Fokker SO profusely used, on not only the Eindecker, but going forward into the early biplane fighters (D.I though D.IV, I believe) that Martin Kreutzer had designed for Herr Fokker.

Some of you MIGHT be curious WHY that "soffit", along the upper forward area of the fuselage sides, just behind the cowl's rear edge, was necessary on the later Eindeckers...it sure looks like, to me, that when the move from the Gnôme Lambda clone Oberursel rotary engine, or "umlaufmotor" im Deutsch (the 80 hp, seven cylinder U.0 powerplant) to the 100 hp Gnôme Monosoupape clone (the nine-cylinder Oberursel U.I) was made for the E.II and E.III models, the larger diameter of the U.I mandated a larger diameter "horseshoe" cowl, and larger radius firewall, be designed to fit it.

The forward transverse and vertical dimensions of the Eindecker fuselage, at its forward end (immediately behind the firewall), seems to have remained the same from the M.5K/MG onwards through all of the E.III versions built...and to accomodate the larger diameter firewall/cowl combo the Oberursel U.I required, especially for the UPPER longerons' forward end, "something" had to be done to try to restore the "streamlining" of the Eindecker's nose shape.

The answer was to add a pair of support frames (one per side), extending forwards from the upper longeron's point where it passed forward, through the forward edge of the cockpit opening, outwards slightly in an arclike shape, and then running directly forward to the firewall perimeter, to support the integral extensions from the upper nose's sheet metal panel sides.

The upper nose's metal paneling was then extended to be wider than before, and shaped to overlap this support frame on its side edges, both above it and below it, resulting in the "soffit" shape to those areas of the upper longerons JUST behind the cowl's rear edge.

I've included a small image of JUST this support frame, from the port side of the fuselage...hopefully, you'll clearly see the need for it from my explanation in this post, and its shape in determining just WHY the "soffit" exists for the Oberursel U.I powered versions (the E.II and E.III) of the Eindecker.

(By the way, the E.IV, with its Gnôme DOUBLE Lambda clone twin-row, fourteen cylinder "Oberursel U.III" rotary, had returned to using a powerplant almost identical in diameter to the earlier U.0...its cowl no longer demanded the "soffits" extending off the sides of the upper nose paneling behind the cowl, so they were left off of the E.IV's nose.)

Hope this post helped a bit further in understanding just WHY that "soffit" exists along the upper longerons of MOST Eindeckers, just behind the cowl's rear edge!

Yours Sincerely,

The PIPE!

[Lufbery]

Thanks for the additional information.

Regards,