Putty on joints to make skin flush

GregP · Feb 12, 2016

I've seen the process of reprofiling a wing on 3 or 4 Reno racers. They apply putty, and sand until smooth; then sand until it matches the profile template laid over the wing surface. The intent is to change the basic airfoil shape, not cover rivets. It works.

I can imagine that in wartime, they sprayed and then sanded until they just started to see the tops of the rivets, stopped, wiped with tack cloth, and painted. You'd never see the rivets after painting. If using flush rivets, it would take complete care of the occasional raised rivet head that is proud by maybe 0.001" due to poor countersinking.

Not sure if everyone is aware, but the Mooney Acclaim is the fastest piston single of the nominal 4-place variety. It is flush riveted for only about the front 1/3 of the wing and has universal rivets on the rest s you move to the trailing edge. That tells me something about the drag and where it is highest.

stona · Feb 12, 2016

Way back in post #6 I posted a link to an instructional film which shows how the British/Commonwealth air forces re-finished a high speed aircraft

GregP said:
I can imagine that in wartime, they sprayed and then sanded until they just started to see the tops of the rivets, stopped, wiped with tack cloth, and painted.

They went a little further than that, as they did in the original production. But it was a developing situation. In early 1940 a circular was sent to all the Resident Technical Officers (RTOs) at the various aircraft plants to inform them of the introduction of the new Type S smooth paints. It makes the point that,

"...the final roughness on many aircraft types is often as high as five thousandths of an inch, and sometimes up to ten thousandths."

By 1942 this was not enough and it was agreed that for the Spitfire both the undercoat and the final coat of paints should be rubbed down,

" in view of the general conditions under which the paint spraying processes are carried out at Supermarines."

For the wing it was realised that the area as far back as 20% of the chord was most important and it was agreed that,

"great care should therefore at the same time be taken to fill up the plating joints, indentations at rivet heads etc., in this region and in particular the butt joint which traverses the whole of the leading edge spanwise."

The introduction of these measures was estimated to require 50 man hours per air frame (one quarter skilled) and the impact on production would be 'negligible'.
Supermarine was to pass on the details to "Castle Bromwich, Westlands etc" but the MAP would issue direct instructions to the firms,

"...to ensure that this improvement in aircraft finish will in a reasonably short time be generally applied to Spitfires."

50 hours extra work per aircraft may have seemed negligible in the big scheme of Spitfire production but it is still a not inconsiderable investment for an estimated (by Supermarine) 5 mph improvement in top speed.

Cheers

Steve

MiTasol · Feb 15, 2016

GregP said:
Not sure if everyone is aware, but the Mooney Acclaim is the fastest piston single of the nominal 4-place variety. It is flush riveted for only about the front 1/3 of the wing and has universal rivets on the rest s you move to the trailing edge. That tells me something about the drag and where it is highest.

Another example of what GregP says about the first half of the wing being the critical area. Competition aerobatic aircraft depend on clean aerodynamics to ensure that their performance is as high as possible. The Russian Sukhoi piston aerobatic aircraft have a wing trailing edge some 10 to 12 mm thick.

MiTasol · Feb 15, 2016

MiTasol said:
[QUOTE="Aozora, post: 1063232, member: 51628"
Hi Aozora (or is that Gidday)
It would appear from the above page that you have, or have access to, a copy of the P-51 manual 01-60JE-2
I have just obtained a copy that has been used as a childs scribble pad (fortunately with pencil so I can physically and digitally erase most of the damage with a little luck and a lot of work) but it is missing two sheets, pages 1/2 and 173/174.
If your manual is the same edition (and your copy and mine are probably the same because page 407 is identical though mine is not watermarked) could you please copy these four pages and post them to the forum or PM them to me.
The attachment shows the manual I have. It is an earlier edition than the manual Avialogs have and those pages are much different in the Avialogs manual (which covers specific D and K models).
According to page A of my manual none of the missing pages were revised in Feb 45 so an original copy of the Dec 44 manual would have the same pages as I need.
Regards
Mi Tasol
.

Make that I now have two versions of P-51 E&M manual 01-60JE-2.
The second is also damaged and missing pages. It is dated Dec 44 revised 20 March 1945. This may be the same as the Avialogs manual but the title page on Avialogs has been butchered to remove the date. My second manual is missing just the front two pages, (Title and Page A) but page B identifies it as 20 March.
If your manual is this edition could you please scan and post those to the forum or PM them to me I can scan and post the rest of the manual after cleaning.
Regards
Mi

Crimea_River · Feb 16, 2016

The entire manual can be found in post 12 here

Mike Williams · Feb 16, 2016

I'll never forget how impressed I was with the finish on the Spitfire VII at the Smithsonian Air & Space museum.

MiTasol · Feb 16, 2016

Thanks Crimea River for that link but unfortunately that is the same manual that Avialogs has which makes it either the March 45 or a later revision (I have not worked out which yet as the title page is butchered and pages A & B are missing). The pages being out of order does not help sort this out so I guess I will have to get them in order so that I can determine which one it is and post the cleaned up copy.

Unfortunately that means I am still looking for the following missing pages

01-60JE-2 P-51 E&M (1944-12-20 Rev 45-03-20) 20 March 1945 Title page and page A

01-60JE-2 P-51 E&M (1944-12-20 Rev 1945-02-05), pages 1/2 and 173/174. Pages from the manual dated 20 Dec 1944 are identical but the Avialogs pages are different because the K models were added in the March 45 or later revision.
Interestingly my copy of this is a reprint as it has no pink pages

Regards
Mi
P.S. I loved Calgary in the late 60's but I guess it is totally different now.

.

Crimea_River · Feb 16, 2016

I guess I did not look closely and now realize that the copy I have is also screwed up. Sorry I couldn't help.

And yes, Calgary would be very different now from when you remember it. Over 1MM people now.

MiTasol · Feb 17, 2016

Crimea_River said:
I guess I did not look closely and now realize that the copy I have is also screwed up. Sorry I couldn't help.

No sweat. I would rather a wrong lead than no lead at all so thanks for the effort regardless. More than one wrong lead in the past has had great value.

Aozora · Mar 4, 2016

MiTasol said:
Hi Aozora (or is that Gidday)
It would appear from the above page that you have, or have access to, a copy of the P-51 manual 01-60JE-2
I have just obtained a copy that has been used as a childs scribble pad (fortunately with pencil so I can physically and digitally erase most of the damage with a little luck and a lot of work) but it is missing two sheets, pages 1/2 and 173/174.
If your manual is the same edition (and your copy and mine are probably the same because page 407 is identical tho mine is not watermarked) could you please copy these four pages and post them to the forum or PM them to me.
The attachment shows the manual I have. It is an earlier edition than the manual Avialogs have and those pages are much different in the Avialogs manual (which covers specific D and K models).
According to page A of my manual none of the missing pages were revised in Feb 45 so an original copy of the Dec 44 manual would have the same pages as I need.
Regards
Mi Tasol
.

Gidday Mi Tasol
My copy of 01-60JE-2 is from Avialogs as well, except that I have managed to unscramble the pages;
AFAIK, these pages 173 & 174 should be the ones you're looking for?

Pages 1 & 2: hopefully, these are what you're needing:

For interest, I also have an NAA E & M Manual, NAA-5865, dated March 1944 - this is for the P-51D-5s:

BiffF15 · Mar 4, 2016

Mike Williams said:
I'll never forget how impressed I was with the finish on the Spitfire VII at the Smithsonian Air & Space museum.

Love the Keith Ferris painting as well! I was amazed as a kid that someone could do something like that and it "look normal" when finished!

Cheers,
Biff

MiTasol · Mar 4, 2016

Aozora said:
Gidday Mi Tasol
My copy of 01-60JE-2 is from Avialogs as well, except that I have managed to unscramble the pages;
AFAIK, these pages 173 & 174 should be the ones you're looking for?
Pages 1 & 2: hopefully, these are what you're needing:
For interest, I also have an NAA E & M Manual, NAA-5865, dated March 1944 - this is for the P-51D-5s:

Thanks Aozora

Pages 1 and 2 do look like those I need - very many thanks

Page 173/173 are pink pages (revised) and I need the original white pages - someday hopefully they will be found.

I think it safe to say that I am not the only person who would love to see a copy of the NAA E & M Manual, (NAA-5865, dated March 1944) posted to the site.

Many thanks

Mi

Putty on joints to make skin flush

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