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Martlet Mk.I


jabbajindrich

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Greetings everybody,

I prepare myself for new project, Martlet Mk.I from Trumpeteer F4F-3 in 1:32 scale, but I am very suprised about lack of fotodocumentation and detail drawings of this type, especially when one survivors is in FAA museum (unfortunately or fortunately several years under restauration process).

Engine cowling and nose part should be scratchbuild so that´s my reason for accuracy. Wing modification is easier part of job.

Any help is very appreciated, walkaround is a gift from heaven,-).

Thanks in advance.

Jindrich Nepevny,

Prague, Czech republic

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Greetings everybody,

I prepare myself for new project, Martlet Mk.I from Trumpeteer F4F-3 in 1:32 scale, but I am very suprised about lack of fotodocumentation and detail drawings of this type, especially when one survivors is in FAA museum (unfortunately or fortunately several years under restauration process).

Engine cowling and nose part should be scratchbuild so that´s my reason for accuracy. Wing modification is easier part of job.

Any help is very appreciated, walkaround is a gift from heaven,-).

Thanks in advance.

Jindrich Nepevny,

Prague, Czech republic

Hi!

Visit this page as it will help you. http://www.clubhyper.com/reference/wildcatfaaba_1.htm

There are several differences between the Cyclone powered Martlets and the P&W powered ones. The cowl is shorter, and rounder, and shaped very differant than the P&W cowl and the fuselage is longer between the wing and cowl.

Bruce

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Many thanks for support from all of you,

I manage to collect a lot of info about Martlet Mk.I (how differ from F4F-3 etc.), but still missing details like undercarrige space, nose frpom cocpit onward, modified engine cowling, engine compartment etc.

Few pictures from MAM magazine (back issue from 2008 or 2007) are really excellent, indeed; however too small to provide sufficient details for schratchbuilding in 1:32 scale.

Is there any chance to acquire more details fotos from FAA surviving plane ?

By the way, when Martlet Mk.I restoration work will be finished ?

bstrgds

J.Nepevny

Czech republic

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Wow, thanks Claudio, that was great! I also enjoyed imagining my own soundtrack- "Oh bugger, where the hell are my car keys?" and later, "They're down there- see if you can reach them." I don't think I ever saw a Wildcat appearing to move so fast, either!

bob

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I hope so,

I will expect a lot of "under skin" details as well as more other Martlet Mk.I pictures.

Only two questions last - when the restoration will be complete and haw long we will have to wait for the BOOK ?

I still hesitate to continue with my Martlet Mk.I project, because the selected scale is to big and lot of "question" still unsolved.

Any detailed pictures are still very appreciated. It is pitty that MAM magazine have not web archive with more pictures or with the same picture with more resollution.

Many thanks in advance.

best regards

Jindrich Nepevny

Prague,

Czech republic

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Here is another oft-referenced link, copied from a recent post here--an excellent article by Bruce Archer showing all Martlet variants:

http://www.clubhyper.com/reference/wildcatfaaba_1.htm

The Martlet Mk. I is a very interesting animal. It was actually the very first variant of the F4F "family" to enter military service, preceding the US Navy's F4F-3 by many months. The installation of the Cyclone engine and wing guns are unique to the variant, and it has a very clean appearance overall.

One frequently-missed difference with the Martlet I, is that the windscreen is farther to the rear--and thus the sliding portion of the canopy is shorter--than any subsequent variant. If you will study the very first photo in the Archer article, and compare it to the side-view of the Martlet Mk IV later on, you can immediately see this.

Look particularly at:

The relationship between the windscreen and the instrument panel coaming within the cockpit.

The distance from the base of the windscreen to the firewall (the panel line where the backup post gunsight is located).

The proportions of the two panels on the side of the sliding portion.

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As a Wildcat/Martlet nut from my early days of modelling, I hope no-one will object if I ask what I hope is a simple question. What is the difference between the ex French contract G-36As & a Martlet MkI, Its not obvious from Bruce's treatise on Hyperscale afaiks, but I'm Kinda guessing not a lot?

Steve.

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They are one and the same; the G-36A order could not be delivered to France and was sent to the FAA instead, where it was designated Martlet I.

Others here will be far more versed in the details than me, but the machines were fitted either in the US or UK with British equipment (guns, radios, throttle, instruments, etc.), as well as camouflage and markings of course.

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One frequently-missed difference with the Martlet I, is that the windscreen is farther to the rear--and thus the sliding portion of the canopy is shorter--than any subsequent variant.

Sorry, but I'm not yet convinced. Certainly there seems to be a difference in the location of gunsight/instrument panel coaming, but I don't know that the shape of the windscreen/canopy has changed. Note that in the Mk.IV photo the wingtip is slightly obscuring the bottom edge, especially altering the apparent shape of the windscreen.

You may be right, but I need more convincing.

bob

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Gingerbob, thanks for your comments. Here's some more stuff to (hopefully) bolster my point re: the diffferent windscreen position and shorfer sliding canopy on the G36 A / Martlet I, when compared to subsequent variants.

I'm not suggesting that the actual structure of either the fuselage, or the windscreen, changed in any substantive way; merely that the latter was moved forward at some point.

First some background info--a fuselage station diagram (from FM-2 erection/maintenance manual). Station 2 is the firewall while stations 3, 4, and 5 respectively frame the front, middle, and rear of the cockpit.

fm2_fus_struct.jpg

Now, two shots of Martlet I's. Note that the rear frame of the windscreen is very noticeably closer to frame 4, than frame 3:

martlet_i_fuselage.jpg

martlet_i_canopy.jpg

Two shots of later variants. The rear of the windscreen is very noticeably closer to frame 3, than frame 4. Also note the internal reinforcement at the lower rear corner of the sliding canopy, which is seen on all subsequent variants:

f4f3_ohare.jpg

f4f3_wake.jpg

Frame 2 creates a subtle yet noticeable "kink" in the fuselage profile. Another good point of reference is the distance between it and the base of the windscreen (lines "B" in these shots).

Martlet I:

martlet_i_profile.jpg

Martlet V:

martlet_v_flight.jpg

Chronologically speaking, study of photos shows the rear windscreen position is consistent with prototypes built prior to Martlet I production. The forward position seems to have begun with F4F-3's that followed the Martlet I on the line.

Edited by MDriskill
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Gingerbob, thanks for your comments. Here's some more stuff to (hopefully) bolster my point re: the diffferent windscreen position and shorfer sliding canopy on the G36 A / Martlet I, when compared to subsequent variants.

I'm not suggesting that the actual structure of either the fuselage, or the windscreen, changed in any substantive way; merely that the latter was moved forward at some point.

First some background info--a fuselage station diagram (from FM-2 erection/maintenance manual). Station 2 is the firewall while stations 3, 4, and 5 respectively frame the front, middle, and rear of the cockpit.

fm2_fus_struct.jpg

Now, two shots of Martlet I's. Note that the rear frame of the windscreen is very noticeably closer to frame 4, than frame 3:

martlet_i_fuselage.jpg

martlet_i_canopy.jpg

Two shots of later variants. The rear of the windscreen is very noticeably closer to frame 3, than fframe 4:

f4f3_ohare.jpg

f4f3_wake.jpg

Frame 2 creates a distinctive "kink" in the fuselage profile. Another good point of reference is the distance between it and the base of the windscreen (lines "B" in these shots).

Martlet I:

martlet_i_profile.jpg

Martlet V:

martlet_v_flight.jpg

Chronologically speaking, study of photos shows the rear windscreen position is consistent with prototypes built prior to Martlet I production. The forward position seems to have begun with F4F-3's that followed the Martlet I on the line.

Hi!

Have you taken into account the differing fuselage length between the wing root and cowl between Cyclone powered variants and the Twin Wasp powered variants?

The fuselage was longer on the Martlet I and Wildcat IV and VI. This could cause the appearance of the cockpit moving forward when comparing the Martlet I/IV to the F4F-3/4 and Martlet/Wildcat II/III/IV.

Bruce

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Hello Bruce--as far as I can tell, the changes in fuselage construction to handle different engines all happened forward of the firewall (station 2). The bays aft of station 2 remained the same throughout F4F production.

The area we are discussing is all abaft the firewall, and thus unaffected by the engine installation.

If you compare carefully the Martlet I and Martlet IV (via the following pics shamelessly purloined from your famous article!), which had similar engine bay geometry, the same differences can be noted. The proportions of the sliding portion of the canopy (i.e. ratio of its height to its length) also is different. The Martlet IV pic is not at an optimum angle for these purposes as the panel lines under the cockpit are hidden, but the fixed gunsight post sits right on station 2.

martlet_i_profile.jpg

martlet_iv_profile.jpg

Any of you gents live near the FAA Museum and own a tape measure?

:winkgrin:

Edited by MDriskill
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Any of you gents live near the FAA Museum and own a tape measure?

I don't live near the FAA Museum but did visit with a tape measure in Aug 2010. Museum staff kindly humoured my request to take some of the engine dimensions (a live topic on Britmodeller at the time) from the partially dismantled Martlet I. I was there on sufferance so it was all done in great haste.

Cowling chord ie from front edge to rear edge: 28”

Diameter of cowling front aperture: 40”

Forward fuselage (measured from forward edge of wing flange to where rear edge of cowling would have been had it been installed (ie the rear edge of underlying frame/bulkhead): 1st measurement: 450mm 2nd measurement: 17.5”. (Yes, there's a 5.5mm discrepancy between those 2 measurements: should have made it best of three, sorry.)

No idea how these figures relate to what they "should" be. Hope they help someone, even if not relevant to the interesting current discussion on windscreen/canopy positions.

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Hello,

thank you very much for pointing out these very interesting details.

Another very clear couple of pictures (taken from the opposite side) can be found in Detail and Scale no. 65, pages 73 (Mk. I) and 74 (Mk. IV) and I think they do show that the windscreen changed position and the canopy had different length.

A quick look through D&S and other photos, now that I knew what to look for, suggests that:

  • the same windscreen seen on the G-36A's is also found on XF4F-5, Bu. No. 1847 and on XF4F-6, Bu. No. 7031. On these machines there is seemingly no profile kink on station 2, just as in the G-36A
  • F4F-3, Bu. No. 1844 seemingly went through some changes of windscreen shape
  • F4F-3, Bu. No. 1848 (first production standard machine, delivered December 1940) had the more usual windscreen

This makes me think the Martlet Mk. I windscreen may have been an earlier design. The export Grumman G-36A's were produced through the summer of 1940, mostly before production standard F4F-3's. In the meantime, production inspection trials were being carried out on the F4F-3 (from August to December 1940) and some changes may still have taken place before the start of full-scale F4F-3 production.

For instance, earlier F4F-3 windscreen shapes (on Bu. No. 1844) did not include the flat front panel. A side photograph of F4F-3 Bu. No. 1845 taken in September 1940 shows the windscreen in the forward (later) position, but still with the telescopic gunsight. This might perhaps point to some explanation.

It would be nice to know why the changes were made. I may think that the profile kink would allow to slightly lower the instrument panel coaming and somewhat improve pilot downward visibility. Moving the windscreen forward might suggest more space for the gunsight. But this is just guesswork.

Britmodeller is a wonderful site!

Claudio

Edited by ClaudioN
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Gingerbob, thanks for your comments. Here's some more stuff to (hopefully) bolster my point...

martlet_i_fuselage.jpg

Chronologically speaking, study of photos shows the rear windscreen position is consistent with prototypes built prior to Martlet I production. The forward position seems to have begun with F4F-3's that followed the Martlet I on the line.

Point bolstered, with the help of Dana Bell's book, and Detail & Scale, as well as the newer "in Action" book. Funny thing is I had started from the back end, the first time, and didn't pay sufficient attention to the front end. I don't yet see what you mean about the "kink" created by (or at) Frame 2, but no doubt I will with more study. Dana's book has a very close, clear photo of what he says is the XF4F-3, with telescopic sight, and the windscreen is in the "normal" location (but is a rounded-front style).

If you'll pardon another ignorant (as in, lacking in knowledge) question, how do you know that the photo above is a Martlet I? You can't say "because of the windscreen position", because that's circular logic! The engine no doubt is one indication, but is Martlet I the only possible solution?

Thanks for your patience, and for opening my eyes!

bob

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Hello Bob, first let me say that this superb photo was taken from this link that Daniel Cox posted in one of the replies above....a gold mine of other great details for Grumman fans:

http://www.warbirdinformationexchange.org/phpBB3/viewtopic.php?f=3&t=13327

The machine has a Wright Cyclone single-row engine with underside exhaust outlets, which immediately limits the possibilities to the G-36A (Martlet I) and F4F-4B (Martlet IV). The later FM-2 (Wildcat VI) also had the Cyclone of course but had many modified features not evident here--taller tail, side-mounted exhaust channel, etc.

This is a Grumman factory photo, apparently intended to "compare and contrast" the Wildcat to the hulking TBF Avenger wooden mockup behind it! This likely dates it to late 1940 or early 1941 (first Avenger prototype flew in spring 1941). At that time a G-36A would have been the only type of Cyclone-engined Wildcat sitting around the place; the F4F-4B came along about a year later.

Here are three minor physical differences between the Martlet I and IV:

1. The rotating cockpit ventilator just under the windscreen--this small gizmo is hard to see in this pic, but shows up much better in some of the photos posted above. I don't know exactly what replaced it, but it's no longer present on the F4F-4, F4F-4B, and subsequent variants.

2. Beginning with the F4F-4 and on all subsequent variants up to the FM-2, there is a small air scoop located just aft of station 7, right below the canopy track. This is visible in the Martlet IV profile photo above, but is not present on this machine.

3. There is tiny bar under the very rear of the fuselage, used for towing the machine on the ground and as a hold-back fitting for US Navy "tail-down" catapult launching. On early machines this was attached to the airframe with the surprisingly delicate-looking bracket seen here. The F4F-4 introduced a much stouter triangular bracket.

Lastly, what I mean by the "kink" is simply that the top line of the fuselage is not a single perfectly straight line, from the base of the windscreen to the cowl. Rather, it's a short straight line from the windscreen to the firewall; then a slight downward angle is evident, from there to the longer line that runs more or less unbroken from the firewall to the front ring of the cowl. It is slightly more prominent on the P&W-engined machines since the front of the cowl is slightly smaller in diameter. "Kink" may be too gaudy a term for such a subtle feature!

Edited by MDriskill
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