FM-2 Wildcats!

[Dan K]

Questions for the experts;
1) Have there ever been two or more flyable Wildcats owned by a civilian owner?

Could've sworn I've seen pics online of a pair of old civilian FM-2 sprayers...maybe orange or copper colored with black trim...oversized drop tanks? Ring a bell with anybody?

[Jack Cook]

John Dimmer's FM-2 N20HA.
Jack Lenhardt removed all the spray gear when he bought the a/c.

Last edited by Jack Cook on Fri Jun 03, 2011 7:16 pm, edited 1 time in total.

[Dan K]

Thanks for that, Jack.

Wait'll my wife hears I'm not completely senile (yet).

[Aircraft Mech Paul]

Hi Guys,

I know that this may, on the surface at least, seem a very stupid question, but I haven't kept up with this thread much. But at one time I thought I read that one of these aircraft was from Planes of Fame (?) am I wrong ? And if so, please PM me I have some info on it for you concerning a leading rebuild job done on the right wing some years ago.

Paul

[mustanglover]

Hi Guys,

I know that this may, on the surface at least, seem a very stupid question, but I haven't kept up with this thread much. But at one time I thought I read that one of these aircraft was from Planes of Fame (?) am I wrong ? And if so, please PM me I have some info on it for you concerning a leading rebuild job done on the right wing some years ago.

Paul

The POF right hand wing was a fake wing and has been disassembled and is currently being rebuilt into an airworthy wing. See posts about the wing several pages back.

[Rajay]

Another installment of photos for you all. Lately we've been shooting on the skin on the right stub wing and I've been working on some instrument/interior wiring. This week our covered control surfaces came in and they look great. Thanks Robbie!

Beautiful workmanship, but I have a question about that wiring.

It "looks" like old standard fabric-insulated wire but surely it can't be. Is it some kind of simulated old Mil-spec for appearance of authenticity or is it an actual currently FAA-approved type of wire? Instead of diagonal stripes like it seems to have, I thought that modern aircraft (i.e. to "current" standards - no pun intended) electrical wire carried a single "lubber" line with both generic AWG and specific aircraft model electrical system circuit identifications on it.

Last edited by Rajay on Sun Jun 05, 2011 1:29 pm, edited 1 time in total.

[Cvairwerks]

Rayjay: It depends on what is specified by the print. We buy our wire by the mile and it's almost always plain white jacketed. We laser the id as required for the individual wire/harness. We do have a couple of other jacket colors for some special cases.

[Dan Jones]

This thread really needs to be "stickied".

[fighter_ace06]

I would love to here some history on the fake right wing, and possibly a little more on the airplane. I know it was delivered after the war, then stricken 3 months later. In between that and ending up in chino I have no information. How did it lose the wings?
The wire is normal mill spec and it has been fabric covered then varnished with a single green tracer.

[fighter_ace06]

Just another update for all who are interested. Sorry we have slowed down on the updates a little but we appreciate everyone who is following our progress.

Martin Mars + South Texas = Limited Landing Possibilities?!!





Trying out one of the belly skins.












Newly fabricated wing spar.

[Obergrafeter]

You really got me wondering Conrad??????????? Any more info on the Mars???? Where, which direction was he headed. Maybe I ought to run up to Medina Lake and take a look.....maybe Boerne Lake. That's weird to be in this part of the country. It's so dry any of our Lakes around here would probably dry up with one scoop from that monster.

[LadyO2Pilot]

You really got me wondering Conrad??????????? Any more info on the Mars???? Where, which direction was he headed. Maybe I ought to run up to Medina Lake and take a look.....maybe Boerne Lake. That's weird to be in this part of the country. It's so dry any of our Lakes around here would probably dry up with one scoop from that monster.

Wayne...you read my mind and posted questions first!!! Yes, Conrad, let us know.......and BTW as I told you at Temple, y'all are doing beautiful work and updates are great.

[Pogo]

Yep, looks like the Mars stole the show. Where? What? Why? When? Etc., etc.?

Martin Mars + South Texas = Limited Landing Possibilities?!!

GREAT photo caption too!




(Just kidding, the Wildcat's freakin' beautiful, and THANKS for the update!!)

[Rajay]

Just another update for all who are interested. Sorry we have slowed down on the updates a little but we appreciate everyone who is following our progress.

I have a question or two but first I wanted to go back and completely re-read this thread from the start to see if it had already been discussed. If it was, I didn't see it...

On page 5 you described the stripping process and there was some discussion of the Anodized sheet metal and the unusual sizes - .064 thick sheet metal used on the firewall (for example) then compared to .063 thick aluminum sheet which is common now. We ran into that alot with our Goose; .072 vs. .071, .064 vs. .063, etc. The biggest issue was Grumman's original use of so much .028 - which hasn't been available in a very long time. Fortunately, they may have seen that writing on the wall and the drawings for the fuselage structure and skins includes a note that .032 was authorized as a substitute for .028. It's kinda like the whole 2x4 board issue - which for a long time has been only 1.5 x 3.5 inches.

Anyway, there was further mention of Grumman's use of Anodize for corrosion protection later on page 8. At some point, there was also a comment to the effect that "most of the fuselage was Anodized" but you didn't specifically comment on whether or not the wing structure and parts were Anodized as well.

Now, in this particular photo it shows that you're going back and reskinning the wing(s) with .032 AMS-QQA-250/5, i.e. Alclad instead of Anodized Bare aluminum sheet (which would be spec. no. AMS-QQA-250/4)

We ran into the same kind of thing working on our old Grumman G-21 Goose, which is the same vintage, but because the Goose is intended to still operate in the water, even potentially salt water, we figured that it was very important to go back with the Anodized Bare aluminum sheet, even though the Type 1 chromic acid Anodize that Grumman used way back then is generally no longer available because of its environmental considerations. (Type 2 sulfuric acid Anodize is supposed to be able to meet the same Mil-spec for corrosion protection, but we'll just have to see about that....)

Since you're in Texas and the Wildcat is not a seaplane, that obviously is not as much of a concern for you. I do know for a fact that Alodined Alclad does not last very long in salt water at all. We have a second Goose, built in Feb. 39 and originally owned by Texaco, that at one point while operating in the New Orleans area sank in salt water. All of the original Anodized parts and skins are in relatively fantastic shape, but some of the non-Anodized and Alclad parts have since turned literally to dust.

More significant that just the corrosion issue though, Alclad sheet is something like 5% weaker than Bare sheet because of the non-structural properties of the 1100 grade pure aluminum coating which make up 5% of its overall thickness (.063 and thinner, half that for thicker sizes.)

Here's my questions (in case you were starting to wonder) - are you sure that Alclad is per spec for the wings (or anything else in the Wildcat for that matter - Alclad wasn't spec'd by Grumman for a Goose at all, not in fact until McKinnon came along in the 1960's and used it in some of his mods) and if not, did you take the differences in tensile strengths into account? (All of the Grumman drawings for the Goose include the tensile strength specifications, so I am assuming that so do those for the Wildcat.)

Finally, one additional question; what did you work out about the trim cables on p. 8? We will have the same problem with the Goose and we have been assuming that we'll have to find a new supplier or someone else to fabricate new ones. If you've already come up with a solution, I'd bet it would work for us too - if you don't mind sharing that info.

[fighter_ace06]

First, the Martin Mars was in Del Rio about a month ago on Lake Amistad. I don’t think it is there anymore. No one was allowed to go into the cove to see it but we got lucky enough to get strafed by it while driving. I then drove my car off the highway and proceeded to take pictures but like any good opportunity my memory card was full and I was able to delete a few pictures and catch it again on final.

Second, the entire Wildcat is anodized. As far as I know any aluminum that ever rolled out of Grumman’s "or any company contracted by Grumman" plants was anodized. They took every effort to help protect these airplanes from the elements. Everything was CAD plated or anodized, zinc chromated, painted, painted again, often tar between sealed joints, and even zinc tape or Cellophane tape in between dis similar metals.

The problem we run into when restoring war birds is tooling. Grumman could afford to invest thousands of dollars into tooling and processes because they would be using each over thousands of airplanes. What I’m trying to say is Anodizing is an art that can only be mastered with lots of time and the right equipment and of course money. The Grumman factory had facilities with tanks that could hold a whole fuselage if need be, and enough power to zap it once it was in. When we first started the restoration I searched for a company that could anodize full sheets of aluminum but found no cost effective solutions. We have Alodine tanks now that I was going to add on to but after buying my own anodizing kit and spending two weeks in a small room inhaling fumes, I finally gave up. If anyone knows of a company who can do this or someone who sells aircraft aluminum pre anodized please let me know.

As for the material and thickness, I go by the drawings and AC 43.13. We try to match the thickness as close as possible or the next size up. The trailing edge skin pictured was originally .028 like you say and I replaced it with acceptable .032 alclad. The material differences are minute and because I am not anodizing I chose to use alclad. I have attached pictures which give a good idea as to when we substitute and when we replace with exactly what is called out. You do know we are talking about "Grumman Iron Works" airplanes, the most overbuilt airplane out there.

As for the trim cables I found a guy locally that does rotational flex shafts. I gave him the cables and he is building all new ones. I haven’t gotten them back yet so I don’t know how they turned out. The easiest thing to do would be to mill out the ends yourself and send them out to be swaged. I have included a picture of what our ends look like. Ours even had a quick disconnect at the stub wing for wing removal.