Even more Martlet material

[mdesaxe]

Here are a couple of images that may be useful. The first is the camouflage diagram for Martlet II and Martlet IV aircraft.

It's interesting to note that Grumman calls the undersurface colour "Duck Egg Blue" even though we know from other factory records that it was actually "Sky".

The second, dated March 21, 1941, is of the first F4F-3A (c/n 757) for Greece that subsequently became a Fleet Air Arm Martlet III (serial AX727, according to Bruce Archer's article)

The date is before the German attack on Greece but it is not at all clear what the national markings are. The aircraft is carrying a civil registration NX-26874 and it also has camouflage on the upper surfaces, but I have no idea what the colours may be.

Maurice

[Christopher]

Hi Maurice

Lloyd (Fleet Air Arm Camouflage and Markings) states that the ex-Greek Martlets were painted in USN Neutrality Grey and remained in that colour initially

Christopher

[ClaudioN]

The second, dated March 21, 1941, is of the first F4F-3A (c/n 757) for Greece that subsequently became a Fleet Air Arm Martlet III (serial AX727, according to Bruce Archer's article)

The date is before the German attack on Greece but it is not at all clear what the national markings are. The aircraft is carrying a civil registration NX-26874 and it also has camouflage on the upper surfaces, but I have no idea what the colours may be.

Maurice

Maurice,

two more pictures of NX-26874 in flight appeared in Air Enthusiast Nos. 73 and 77. Although the aircraft is generally considered to be a Greek machine, I am not convinced at all.

All pictures of ex-Greek machines in FAA use evidence two recognition features:

1) the Curtiss Electric propeller has no spinner;

2) there is a small teardrop shaped bulge on the lower fuselage in front of the wheel well.

These are typical of all F4F-3A's and agree with the fact that the Greek machines were diverted from an USN order.

Looking at the picture of NX-26874, it is clear that:

1) the Curtiss Electric propeller has a small spinner, a feature shared only with the British Martlet Mk. II's, to my knowledge;

2) the small bulge on the front fuselage is absent.

In fact, NX-26874 looks more similar in details to the prototype XF4F-6 and, remarkably, to Martlet A.M. 958. A picture of the former appears on Bert Kinzey's in Detail and Scale no. 65, while a picture of the latter is reproduced in several places. Both are perfect side views, from which it is very difficult to tell whether those aircraft had the carburettor intake at the top of the cowling but, to me at least, a small lip appears to be there, suggesting the intake was in fact present both on the XF4F-6 and on A.M. 958.

The position and size of the obliterated markings on NX-26874 and the close similarity with the camouflage of A.M. 958 also point me definitely towards the idea that this was not a machine destined for Greece, but a fixed-wing Martlet Mk. II from the first batch of 10, the last two of which (A.M. 962 and A.M. 963) were delivered on 19 March 1941. A civil registration would arguably have been necessary for the delivery flight (to Canada, I assume).

Claudio

[MDriskill]

The small bulge accommodated a corner flange on the supercharger intercooler. Intercoolers were not mounted on the Martlet II and F4F-3A/Martlet III, which used single-stage supercharged versions of the P&W R-1830.

 

But you are quite correct, the bulge nevertheless invariably appears on production single-stage aircraft! I would speculate this was just a rationalization issue--i.e the bulged panels were used because they were already available, and caused no functional issues.

 

My point being, the Greek aircraft had the bulge but did not NEED it, so it's entirely possible that prototype or pre-production a/c, such as seen in the photo, may not have had it.

Edited June 18, 2017 by MDriskill

[ClaudioN]

The small bulge accommodated a corner flange on the supercharger intercooler. Intercoolers were not mounted on the Martlet II and F4F-3A, which used single-stage supercharged versions of the P&W R-1830.

The bulge nevertheless often appears on single-stage aircraft though! Just speculation on my part--I suspect this was just an effort to rationalize production. I.e., perhaps the bulged panels were mounted on production single-stage machines simply because they were available and caused no functional issues.

My point being, the Greek aircraft did not NEED the bulge, so it's entirely possible that prototype or pre-production a/c, such as seen in the photo, may not have had it.

I entirely agree with your speculation: surprisingly, all pictures I've seen of ex-Greek F4F-3A's in FAA use, as well as all those of folding-wing Martlet II's, do have the bulge though they all did not need it. Thus, a foreign Twin Wasp engined F4F without bulges must be a very early production aircraft.

Did anybody come first? The 10 fixed-wing G-36B's, the 30 F4F-3A's diverted from the USN order, or were they just interspersed on the production line?

Just a speculation on my part, this time: Martlets in the Western Desert retained the USN light gray for quite some time, and were camouflaged much later. If the Greek machines had been camouflaged, why return them back to a USN peacetime finish?

No positive evidence to support my view, just a few hints.

Best regards

Claudio

[MDriskill]

ClaudioN said:

Did anybody come first? The 10 fixed-wing G-36B's, the 30 F4F-3A's diverted from the USN order, or were they just interspersed on the production line?

According to the motley collection of books I have on hand, the 65 F4F-3A machines were assigned US Navy BuAer serials 3905-3969. This puts them at the end of the first F4F-3 production batches, but before the later -3 variant with 8 cooling flaps (3970-4057), and the first F4F-4's (beginnning with 4058). The Martlet III entered FAA service around August 1940 I think?

 

The Martlet II, directly purchased by Britain and thus not assigned BuAer serials for Lend-Lease, seems to have been built in the same timeframe. One is tempted to think the folding-wing ones were constructed after the F4F-3A, but I can't prove that. The Martlet II reached the FAA in March 1941, some 8 months before the first folding-wing F4F-4's reached the US Navy.

Edited June 18, 2017 by MDriskill

[gingerbob]

I've got some information about the fixed vs folding question, but I'll have to report back later. For now I'll just say that the British ones entered service first because Roosevelt/the US agreed to let the British get the folding ones first. Speaking broadly, once the folding wing was in production they were all built that way- not continuing fixed-wing in parallel with the folding. [Note: this does not include the later batch of -3s (3As?) that were a special case.] Granted there would have been some transitional period.

bob

[gingerbob]

Sorry, got a little confused about the parallel Martlet threads! I've now posted some data on the other thread.

bob

[ClaudioN]

Sorry, got a little confused about the parallel Martlet threads! I've now posted some data on the other thread.

bob

Bob and MDriskill,

thank you very much for your replies.

I was suprised to learn, from the extracts of official documents posted by Bob (on the other thread), how early the story of British Martlets started. In fact, with the G-36A first flying in May 1940 and the G-36B in October, it seems rather clear that both the XF4F-5 (June) and the XF4F-6 (November) actually followed. The evaluation of, respectively, the R1820-40 and R1830-90 carried out on these aircraft seems mostly related to the development difficulties of the two-stage supercharger for the F4F-3 and the search for a viable alternative powerplant for the USN machines.

Returning to the topic of my first post, I would add from these information that, quite likely, it was the XF4F-6 that looked like the British fixed-wing G-36B, not the opposite. No positive evidence about NX-26874, just a very small hint.

A little more info that might be of interest:

1) a Camouflage Diagram for the Grumman G-36, based on the official Air Diagram 1173, Issue 1, had been accepted on 8 March 1940. I can't recall where I read this, but it seems to imply that British interest in the G-36B dated from early 1940;

2) the batch of 95 F4F-3A's is part of a total of 243 aircraft, including F4F-3's and first few F4F-4's, that were allocated consecutive Bu. Nos. (from 3856 to 4098) and Grumman c/n (from 738 to 980). That number would agree with a pre-war USN practice of orders to multiples of 27 (18 squadron aircraft plus 50% reserves - 243 = 27x9) and might have started as a single large order in about mid-1940;

3) a reader's letter in Air Enthusiast no. 75 attributes the identification of NX-26874 as a machine destined to Greece to a 1992 publication of IPMS Greece.

Happy modelling

Claudio

[BD1944]

I think this is AM954, the first of the Interim Mk. IIs, which was not delivered but retained by Grumman for development testing (read: troubleshooting?) I can't find my reference for this offhand but it's in my synopsis notes. For a decent version of THE photo of AM958, see http://www.worldwarphotos.info/gallery/usa/aircrafts-2-3/f4f-wildcat/grumman-martlet-mk-iii-am958/

which shows the top lip intake (just) and the lack of supercharger blister.

I think it's fair to say the Mk. II(int)s were effectively pre-production F4F-3As. (They seem to have been redesignated as Mk.IIIs in July 1941.) The Martlet II was ordered in its own right (not a windfall like the Mk. I) and the RN took Grumman's advice about the "best" engine: but they couldn't have the '1830-76, it wasn't cleared for export.  Presumably the performance of AM954 with the commercial '1830 was good enough for the USN to order the stop-gap F4F-3A with the military equivalent, the '1830-90 - and provision to retrofit the -76 when they became available.

I think we've identified a second Mk. II(int) photo. Not bad for nearly 75 years on!

Edited June 15, 2017 by BD1944
misprint