All the Wildcat/Martlet questions you wanted to ask

[detail is everything]

The various wildcat/Martlet variants and their features have been the subject of much discussion and the latest topic

has strayed from its original question to a wider discussion concerning engine variants, production details and other matters. 

 

Other relevant posts include 

 

 

 

There are many others

 

Any way I thought as requested, we start this topic for any wildcat/Martlet queries

[825]

This piece in Hyperscale is a really helpful resource. http://www.clubhyper.com/reference/wildcatfaaba_1.htm
 

I think it’s referenced in a few of these threads. 

[detail is everything]

8 hours ago, 825 said:

This piece in Hyperscale is a really helpful resource. http://www.clubhyper.com/reference/wildcatfaaba_1.htm
 

I think it’s referenced in a few of these threads. 

In deed.  However there is an apparent error in it and other published references as discussed in the Grumman F4F-3 colours thread above.

 

It is quite a complex picture with regard to the various F4F variants and the engines they used. What I thought was established truth, has subsequently been thrown into doubt or even disproved.  Sometimes it is how you personally interpret the information provided.

 

Don't assume a particular published reference is the definitive guide.  Quite often contradictions and errors are thrown up when multiple references are compared, and new emerging reference material can sometimes reveal new details - some of the ex Greek Martlet IIIs in E Africa not having the usual cowling top carburettor air scoop being a recent example.

 

[Bruce Archer]

You mention an error in the article I wrote. Would you be kind enough to tell me what it is so I can evaluate it?

 

The first Martlet Mk.IIs came directly from USN production. They were built to F4F-3 standards with the intercooler scoops and the carb intake at the 12 o'clock position. These 10 aircraft were redesignated MK.III.

 

I not only used the references listed, but LOTS of images and serials. Plus when I started to write the article ( 9 years in the making!) the Grumman historical office was open, and the girls who ran it were immensely helpful

 

Bruce

Edited September 22, 2022 by Bruce Archer

[Geoffrey Sinclair]

1 hour ago, Bruce Archer said:

You mention an error in the article I wrote. Would you be kind enough to tell me what it is so I can evaluate it?

Differences.  RAF Contract Cards.

Mark I Did not use serials AL231 to 235. Article lists AX824 to 829 as both Martlet I and III.  The 81 Martlet I serials were AL236-AL262 (At RNAS Donibristle November and December 1940) , AX824-AX829 (at Scottish Aviation August 1940), BJ507-BJ527 (At Scottish Aviation September 1940 on) and BJ554-BJ570 while BT447-BT456 were allocated to the 10 lost at sea.  AL231 to 235 cancelled, replaced by AX824 to 829, so 5 cancelled, 6 replacements.

 

Mark II, minor point, the article lists the loss of AM954 in the mark II section, but the AM954 to 963 block "covered in the Mark III section."  AM954 initially retained in US, lost at sea US/UK, S.65363, Movements 6, 23 Feb 42.

 

RAF Contract Cards, mark II Lost at sea differences.
Shipped direct from NY to Bombay 15 Mar 42, Shipping folder Enc 247/1 AJ100 to 102, 105, 106, 108 no mention of lost at sea.
Lost at Sea, S.65363 Movements 6, 23 Feb 42, (en route to UK?) AJ107, AJ109 to 111
(RAF Serial Registers have blank entries for the AJ serials except AJ107, 109 to 111 marked lost at sea)

AJ124 to 126, China Bay, allotment 1348/42, April 1942, no mention of lost at sea

AJ138 to 145, China Bay, allotment UK 6400, 16 April 1942, no mention of lost at sea.

 

(RAF records AM955 to 963 on strength May/June 1941, AM964 to 999 December 1941 to March 1942, AJ100 to 153 March to June 1942., acceptances in USN were 10 in March 1941, 1 in June, then 49 August to December 1941, 1 in February, 33 in March and 6 in April 1942)

 

Mark III, RAF Serial registers, AX724 to AX747, AX753 to AX754, AX761 and HK840 to HK842, total 30.  Serials allocated in Middle East.  Import report 27 mark III arrived Middle East in July and 3 in October 1941. (AX748 to 752 Anson, 755 DC-2, 756 to 759 Lodestar, 760 DH.86)

 

USN record of acceptances, Mark VI serials JV637 to JV924 and JW785 to 836, total 340, article is missing JV903 to 924, adds JZ860 to 889.

[detail is everything]

22 hours ago, Bruce Archer said:

You mention an error in the article I wrote. Would you be kind enough to tell me what it is so I can evaluate it?

 

@Bruce Archer Thanks for responding.

 

It is the question of which engine variant was used by the the 10 fixed wing G36Bs.  You say 'These ex-Mk. IIs were powered by a Pratt and Whitney R-1830-76 Twin Wasp with a two-speed two-stage supercharger. 

 

However, it has been claimed that the first ten Martlet IIs (later IIIs) had the same engine as the next 90 aircraft,  the Pratt & Whitney Twin Wasp S3C4-G (equivalent to the P&W R-1830-90), that was "supplied" (acquired and paid for) by the British. Comparison of side-view photos of the XF4F-6 (Bu. No. 7030) and the Martlet II/III (AM958) show they are virtually the same thing. 

 

Reportedly, the two-stage supercharged variants (R-1830-76 and R-1830-86) were not cleared for export, thus France and Britain had to seek alternative powerplants. France opted for the Wright Cyclone G205A for the G-36A.  Britain selected the Pratt & Whitney S3C4-G for the G-36B. This engine was developed into the equivalent R-1830-90 of the F4F-3A.

 

This would make the two Martlet III groups even more similar with both having effectively the same engine and single stage supercharger.

 

I was just interested to know why you thought they were powered by the -76 engine, as you seem confident they did.

 

You might also be interested in the photos showing some of the 805 NAS F4F-3A equivalent Martlet IIIs in E Africa without the cowling top carburettor air scoops, suggesting re-engining with the S3C4-G engine of the Martlet II with their by then production standard internal carb air scoop or at least adoption of the internal carb air scoop when in for deep maintenance.

 

Edited September 23, 2022 by detail is everything
correction of last para

[captnwoxof]

 

On 9/22/2022 at 7:56 AM, Bruce Archer said:

The first Martlet Mk.IIs came directly from USN production. They were built to F4F-3 standards with the intercooler scoops and the carb intake at the 12 o'clock position. These 10 aircraft were redesignated MK.III.

Bruce, with all due respect, I too would like to see your evidence for this assertion. I have combed the PRO files for data on the Martlet, and believe that I have a fairly clear picture of how the 100 G-36B airframes of contract A-1548 (24.7.40) were built and delivered. They were not part of USN production, and they did not have any USN designation.

The differences in the first ten were not just confined to the fixed wings, their cowl and fuselages were built to a different production standard then the 90 that followied. This was a reflection of the time sequence of their production: Their fuselages were finished in December 1940, but production of the contractually specified folding wings was delayed,so they were placed in storage. Constructiion of the remainder of the order was suspended until production of the folding wings finally commenced in August, over nine months late. By then Grumman had adopted several changes to all production. The internal carb air intake had been adopted, as had the small forward fuselage teardrop fairings (although when construction resumed, some early AM series airframes appear to have gotten the last of the old panels that lacked them). So the bulk of the order had these features as well as the folding wing.

Meanwhile, In January 1941 the British became concerned about the effect of leaving the ten fuselages and their engines in storage. A proposal was made that they be fitted with F4F-3 production standard wings, and after some haggling over who would pay for the fixed wings, Grumman agreed. This was done and they were delivered in March.. AM958 was the first to arrive in the UK, on 21.5.41.  PRO file SUPP 9-2 contains pictures and data of US types that were arriving in the UK.

 

https://dsm04pap002files.storage.live.com/y4mNiluK2dutfPlO59yLxxVq4RkxKHrva94r5OiZ-s2HStWIZ--3rflo-e8aLCwh7sDcdc1glC-U9mwqc9OGjzEl70NuVVM8UXSyc1mPVlFEldzGCfPVRTp4RA54PqNnW0LN7ziLiChNhCigHdGub4vbAw6ovOUq3YYg9KE3Lqi7cp9tI5iZWMfYlqUuQGa9aKX?width=1024&height=576&cropmode=none

 

https://dsm04pap002files.storage.live.com/y4maddetdrvkBbCCYxGWyCnRO4sG2gwA3tvmQPCvv0_6wZeAMnDHDiSZQohjyUlqvKJN92bfrqNrTf-i5693qDVFgUtHGgrkGlo9xZm5oXzwxWa8eX1va4-wteNdYEGn605sARVIfAhvIO_jmqRej3pWTvP2PivpDA6ftLjDI3oltCYnQ1YN5e6WXhStmvP0uSp?width=1920&height=1080&cropmode=none

 

https://dsm04pap002files.storage.live.com/y4m2OV7EBd-Q_u-S4s_x_YCNcXkS9Ac1kJdZTCRM0Vkno-H25QIXHwj_PgpsmafqrOqT7rHWAHh7UCzhU8YVlagtQ3WRK9P08cWuPKQcdUo_yiNnBEjlTB0takJF7PtsMW-Z6A2hnbHLfDDT-jE3KP6jKNUOoI0K5VDXQ9UVxv-J0aQwArDS5scMXf5ttT5mD0g?width=1080&height=1206&cropmode=none

 

The first photo is one you know, you used it as a reference in your article. The second one is part of the same series. I haven't seen it anywhere else. It clearly shows that you are correct about the external carb intake, but it also clearly shows the absence of intercooler intakes in the cowl cheeks that would have been present if the engine were a two-stage Pratt. The engine is not a -76. It is a R-1830-S3C4-G  This was the engine supplied by the British under separate contract and installed in all G-36Bs. (commercial equivalant of the military R-1830-90). The data page states this, further confirming the matter.

 While I am confident of my research, I am not infallible. If you have evidence of any of the G-36Bs being fitted with another engine, please let me see it, as I will be open to debate and reconsideration. (AM954 remained at Grumman for many months. I dont know what it was used for. Does anyone?)

Edited September 23, 2022 by captnwoxof

[ClaudioN]

5 hours ago, captnwoxof said:

AM954 remained at Grumman for many months.

Thank you very much for the pictures.

I thought a front view of AM958 had to exist, as it was a standard practice to take pictures for the records from different angles around the aircraft. The IWM web site has instances of such picture series for some aircraft but, unfortunately, only the side view is on-line accessible for AM958.

I believe AM954 was the aircraft seen bearing the US registration NX-26874 in a number of photos. Anybody can confirm this? It would seem consistent with a long stay in the US and maybe could help find out the reasons why.

 

This photo, reportedly from the Grumman archive, was originally posted on BM by @mdesaxe

Note that the aircraft at the top right has folding wings and two pitots on the port wing: the straight, standard F4F-3 one, and the overwing pitot that was fitted to early folding-wing Martlet IIs, presumably adapted from the TBF design.

I presume this arrangement was for comparative trials. It is better seen on another photo I found in the SDASM Archive. Here is the link to Flickr:

https://www.flickr.com/photos/sdasmarchives/4556607946/

I strongly suspect that aircraft is AM954, retained by Grummans possibly to support development of the "British" folding wing.

 

I may be wrong, but I believe initially two different kinds of folding wing were considered:

• XF4F-4: hydraulically folding wing with 4 machine guns (first flown on 14 April 1941, tested in May 1941 and found to be overweight when fully fitted with armour, self-sealing tanks, etc.)
• G-36B: manually folded wing with 6 machine guns (first flown on 8 July 1941)

The fully equipped folding-wing G-36B weighted about 300 lbs less than the fully equipped XF4F-4 and at this point Grumman requested Bu. Aer. approval to use the "British" six-gun folding wing for the production F4F-4 and Bu. Aer. somewhat reluctantly agreed (John B. Lundstrom, "The First Team", Naval Institute Press, pp. 139-140).

Edited September 23, 2022 by ClaudioN

[Bruce Archer]

5 hours ago, captnwoxof said:

 

Bruce, with all due respect, I too would like to see your evidence for this assertion. I have combed the PRO files for data on the Martlet, and believe that I have a fairly clear picture of how the 100 G-36B airframes of contract A-1548 (24.7.40) were built and delivered. They were not part of USN production, and they did not have any USN designation.

The differences in the first ten were not just confined to the fixed wings, their cowl and fuselages were built to a different production standard then the 90 that followied. This was a reflection of the time sequence of their production: Their fuselages were finished in December 1940, but production of the contractually specified folding wings was delayed,so they were placed in storage. Constructiion of the remainder of the order was suspended until production of the folding wings finally commenced in August, over nine months late. By then Grumman had adopted several changes to all production. The internal carb air intake had been adopted, as had the small forward fuselage teardrop fairings (although when construction resumed, some early AM series airframes appear to have gotten the last of the old panels that lacked them). So the bulk of the order had these features as well as the folding wing.

Meanwhile, In January 1941 the British became concerned about the effect of leaving the ten fuselages and their engines in storage. A proposal was made that they be fitted with F4F-3 production standard wings, and after some haggling over who would pay for the fixed wings, Grumman agreed. This was done and they were delivered in March.. AM958 was the first to arrive in the UK, on 21.5.41.  PRO file SUPP 9-2 contains pictures and data of US types that were arriving in the UK.

 

https://dsm04pap002files.storage.live.com/y4mNiluK2dutfPlO59yLxxVq4RkxKHrva94r5OiZ-s2HStWIZ--3rflo-e8aLCwh7sDcdc1glC-U9mwqc9OGjzEl70NuVVM8UXSyc1mPVlFEldzGCfPVRTp4RA54PqNnW0LN7ziLiChNhCigHdGub4vbAw6ovOUq3YYg9KE3Lqi7cp9tI5iZWMfYlqUuQGa9aKX?width=1024&height=576&cropmode=none

 

https://dsm04pap002files.storage.live.com/y4maddetdrvkBbCCYxGWyCnRO4sG2gwA3tvmQPCvv0_6wZeAMnDHDiSZQohjyUlqvKJN92bfrqNrTf-i5693qDVFgUtHGgrkGlo9xZm5oXzwxWa8eX1va4-wteNdYEGn605sARVIfAhvIO_jmqRej3pWTvP2PivpDA6ftLjDI3oltCYnQ1YN5e6WXhStmvP0uSp?width=1920&height=1080&cropmode=none

 

https://dsm04pap002files.storage.live.com/y4m2OV7EBd-Q_u-S4s_x_YCNcXkS9Ac1kJdZTCRM0Vkno-H25QIXHwj_PgpsmafqrOqT7rHWAHh7UCzhU8YVlagtQ3WRK9P08cWuPKQcdUo_yiNnBEjlTB0takJF7PtsMW-Z6A2hnbHLfDDT-jE3KP6jKNUOoI0K5VDXQ9UVxv-J0aQwArDS5scMXf5ttT5mD0g?width=1080&height=1206&cropmode=none

 

The first photo is one you know, you used it as a reference in your article. The second one is part of the same series. I haven't seen it anywhere else. It clearly shows that you are correct about the external carb intake, but it also clearly shows the absence of intercooler intakes., characteristic of all the two-stage Pratts. The engine is not a -76. It is a R-1830-S3C4-G  This was the engine supplied by the British under separate contract and installed in all G-36Bs. (commercial equivalant of the military R-1830-90). The data page states this, further confirming the matter.

 While I am confident of my research, I am not infallible. If you have evidence of any of the G-36Bs being fitted with another engine, please let me see it, as I will be open to debate and reconsideration. (AM954 remained at Grumman for many months. I dont know what it was used for. Does anyone?)

Unfortunately, I cannot open the images you posted.

 

My main source for the first 10 Mk.II (Later Mk.III) Martlets is from Grumman's Historical office. According to the women who ran the office, the original order was for F4F-3 equivalent Martlets. When the BPF and FAA learned about the folding wings the order was changed. The BuAer thought the manual folding wings would be more than adequate for carrier use, and that hydraulically powered would take too long to perfect, and cause too much of a weight penalty degrading performance too much. The BuAer preferred 4 gun wings with more rounds per gun.

 

From the 11th airframe on (AM964) the MK.II was fitted with a Pratt & Whitney R-1830-90 Twin Wasp ( easy to identify as the magnetos were moved to the rear of the engine). The pitot on top of the wing for all AMXXX serialed Martlets was the first attempt at a folding wing pitot and was not completely successful. The newer and better pitot was used on AJXXX serialed Martlet IIs. The FAA  AMXXX serialed Martlets IIs were the only F4F/Martlet to receive the above wing Pitot.

 

The lost at sea serials were put together from several sources, and if your serial disagrees with mine, let me know the sources you used.

 

Bruce

 

 

 

 

 

 

Edited September 23, 2022 by Bruce Archer

[Ed Russell]

6 hours ago, captnwoxof said:

PRO file SUPP 9-2 contains pictures and data of US types that were arriving in the UK.

Somehow you have ballsed up the links so they download rather than open in a new tab or window.

[Geoffrey Sinclair]

1 hour ago, Bruce Archer said:

From the 11th airframe on (AM964) the MK.II was fitted with a Pratt & Whitney R-1830-90 Twin Wasp

As has been noted the S3C4-G is essentially equivalent R-1830-90.  The USN record of acceptances notes all Martlett II as built were powered by an R-1830-S3C4G.  US National Archives, Record Group 72 Entry 153 Box 1 Naval Aircraft Record of Acceptances 1935-1946, Bureau of Aeronautics, Navy Department, Washington D.C., NAVAER 15838

 

1 hour ago, Bruce Archer said:

The lost at sea serials were put together from several sources, and if your serial disagrees with mine, let me know the sources you used.

The sources were given in the message.  The RAF Contract Cards and Serial Registers.  The former tracks orders, listing serial numbers and details like when delivered etc.  The latter is tracking the arrival of new aircraft and initial deployment.  As the Fleet Air Arm had officially become independent in 1939 the RAF steadily stopped tracking RN aircraft, but do have entries for some of the Martlet orders.  These are what have been quoted. Note for example agreement of shipping details for AM954 and AJ107, AJ109 to 111.

Serial Registers, covering K1000 to RZ49, RAF Museum microfilm, 5 files MF-1 to 5.  Similarly the contract cards for roughly the same period, 4 microfilms, MFC-78-1 to 4.

 

The reported change over or pitot types, where the 46 AM serials had one type and the 54 AJ serials another, is interesting, as this does not match any break in acceptances or construction numbers, implying it was done at RN request.

[detail is everything]

As alluded to elsewhere on BM, some early Martlet IIs with "A.M." serials had British-spec catapult spools, and an extended lower fairing which may have had something to do with the fuel system between the landing gear, as seen in the shot below.  AJ series aircraft did not have this extension.  Can anyone shed further light as to why this particular sub-set of airframes had this extended lower fairing and why it was then dropped?

 

Edited September 23, 2022 by detail is everything

[MDriskill]

This thread will be a great resource! Thanks so much for getting it going.

 

Here's another link worth having "up front" I think: Jumpei Temma's superb drawings (probably also included in some of the other attached threads). IMHO the best Wildcat drawings yet published.

 

http://soyuyo.main.jp/fm2/fm2e-1.html

 

Near the bottom are very useful comparative profiles of the three Cyclone Martlet variants.

 

Edited September 23, 2022 by MDriskill

[Geoffrey Sinclair]

A note for Jumpei's web site.  The F4F-4 and FM-1 length when resting on the undercarriage was exactly 29 feet, spinner tip to rudder tip.  When in level flight the length was 28 feet 9 and 3/8 inches.  According to the Bureau of Aeronautics.

[captnwoxof]

6 hours ago, Bruce Archer said:

Unfortunately, I cannot open the images you posted.

 

I am sorry to hear that. I am new to posting here. I followed the site's instructions, using Windows OneDrive. If the links are opening as downloads, can you retreive and view them?

6 hours ago, Bruce Archer said:

My main source for the first 10 Mk.II (Later Mk.III) Martlets is from Grumman's Historical office. According to the women who ran the office, the original order was for F4F-3 equivalent Martlets. When the BPF and FAA learned about the folding wings the order was changed.

My main sources come from the other side of the pond, the files at the PRO in Kew. These contain original correspondance between Grumman, the British Purchasing Comission, the Air Ministry, and the Admiralty. There is a lot there, far too much to present on a webpost.  After review, my main takeaway was that almost everything held to be true about the Martlet is shockingly inaccurate (or to be kinder, grossly distorted.)

The " original order" that resulted in the 100 G-36Bs was not for "F4F-3 equivalent Martlets". It was for a follow-on order to the 81 G-36As of the French order. Although the British examined the G-36 prototype in 1939, they concluded that it was unsutible due to lack of a folding wing, and declined to place an order. The French did, signing Contract No.113 for 81 airframes (Grumman G-36A) with an option to purchase a further 100 at a reduced price. The first airframes were complete, but undelivered when France was invaded. On June 16 1940, the French "sold" all outstanding arms contracts to the British for the sum of one USD (a dramatic and fascinating political story, but not for now,) The contracts had to be transferred to the BPC, but even before this was complete Grumman enquired on June 29 as to whether the British wanted to exercise the option for the 100 additional airplanes. Fast action was required, the option would expire August 1.  The British, as the French had, would have to supply engines. They didn' have enough Wright R-1820-205As, but they had sufficient Pratt & Whitney R-1830-S3C4Gs.  Grumman assured them that the F4F-3s P&W installation could be adapted to take this engine. The British insisted on folding wings. The Admiralty regarded them as essential.  Grumman assured them that the folding wing prototype under development would be in production by the time that construction of the second order began, and that they could be incorporated in the design. Based on these assurances, the British Air Commision recommended and the Air Ministry approved exercising the option to purchase the airplanes. Grumman designated this variant the G-36B. It did not have any direct USN F4F equivalent.

The French contract No.113  became BPC Contract F-292 on June 5 1940. The original terms and specifications remained unchanged, except to replace France with the UK as the second party. The original 81 aircraft were completed as G-36As and delivered to the British. Ten were lost in shipping, the remaining 71 served with the FAA, designated as the Martlet I.  

The "option" for 100 additional aircraft was formalized as BPC contract A-1548 on July 28. It specified 100 complete airframes plus 40 sets of addition folding wings. The Admiralty wanted the extra wings for two purposes. It was proposed to hold 20 of them as a reserve against damaged G-36Bs. It was proposed to use the other 20 to convert some of the G-36As to folding wing Martlets.

That was the plan. The folding wing was not a "change" it was part of the contract from the start. As outlined in my previous post, things didn't work out. The folding wing became a fiasco, and Grumman did not want to acknowlege it, not at the time (and probably not to this day). It is sad to read through the correspondance as assurances fail, delays mount, and optimism fades. Kind of like going back in a time machine and strolling the deck of the Titanic while it sinks.  

The different appearance of the first ten G-36Bs was a factor of the timing in their construction. They were started in December 1940 and finished in February 1941, concurrent with the last of the early F4F-3s and the F4F-3As. Thus they reflect design feature of those airplanes. Seeking to resolve P&W cooling/induction problems, Grumman made a number of changes. Production of G-36B fuselages resumed in the summer of 1941, and the later airplanes have features in common with the late F4F-3 and F4F-4s that were then in production.

Grumman's long affiliation with the US Navy may have created a tendancy to view things through a USN lens. Perhaps this is why the personal at the Historical Office expressed an "F4F-centric" view.

Oh- the extra 40 sets of wings? Great plan, but it did not happen. I have at least two documents noting that the order for them was canceled. Despite all the claims, I find no evidence that any Martlet I or II with fixed wings was converted to folding. 

The re-designation of the fixed wing Mk IIs as Mk IIIs makes perfect sense. They were in mechanical and technical aspects identical to the USN F4F-3A, (of which the FAA had just accquired 30 examples from USN stocks). But they were G-36Bs that got to that state through a convuluted evolution, and there were minor differences that identify them. They lacked the teardrop fairing forward of the wheel well that all F4F-3As had, and they had the pointed dome Curtiss propeller hub rather than the stepped style. 

9 hours ago, ClaudioN said:

believe AM954 was the aircraft seen bearing the US registration NX-26874 in a number of photos. Anybody can confirm this? It would seem consistent with a long stay in the US and maybe could help find out the reasons why.

 

Hi Claudio

Glad you could get the pictures.

I am in agreement that that airplane is probably AM954. It appears to have the camouflage pattern and markings used on the first ten. It may have a straight pitot but I can't say for certain. It definitly does not have the TBF mast style of the folding wing Martlets in the picture (AM964, in the upper right, had both at the time). I wish I had a higher resolution shot, But the intriguing point is that there appears to be an intercooler duct in the cowl. If so, that means a P&W two-stage engine was fitted at some point. If so it was a "one-off", but it could be a factor in what Bruce has stated. This is why I am probing Bruce, not to criticize, but to try to get all the information I can so as to determine what is valid. 

We all seek the simple truth. But what is simple is rarely true and what is true is rarely simple.🙃

9 hours ago, ClaudioN said:

may be wrong, but I believe initially two different kinds of folding wing were considered:

• XF4F-4: hydraulically folding wing with 4 machine guns (first flown on 14 April 1941, tested in May 1941 and found to be overweight when fully fitted with armour, self-sealing tanks, etc.)
• G-36B: manually folded wing with 6 machine guns (first flown on 8 July 1941)

Grumman tried to put the blame for the wing delays on the British for requesting six guns, claiming that the redesign caused the delay, but this was an alibi. The construction of the wing pivot was the problem. First, it required high strength forgings that could only be produced by specialty equipment. Grumman didn't have the necessary tooling and couldn't get the priority to acquire it. The heavy bomber program had a lock on tooling, and nothing was allowed to interfere with it. The Brits went to bat in Washington for them, pleading politics, but it was a no-go. When they finally had sufficient forgings, floor space was a problem, there weren't enough jigs to meet the required quotas, and there weren't enough workers to man extra shifts, The arsenal of democracy was still very much in the building stage.

While I agree that the XF4F-4 wing had just 4 guns, I dont believe that the hydraulic/manual change resulted in any redesign. I think it was just a matter of deleting the hydraulic lines and power components, but I am not entirely sure, and will welcome any hard data,

. 

Edited September 23, 2022 by captnwoxof
typos

[dogsbody]

This image just in, from @Geoffrey Sinclair:

 

 

 

 

 

Chris, for Geoffrey

 

 

 

 

[tempestfan]

10 hours ago, Ed Russell said:

Somehow you have ballsed up the links so they download rather than open in a new tab or window.

I am not a techie but think that if the original file linked to is a pdf or jpg, you will have to download.

[tempestfan]

6 hours ago, MDriskill said:

 

And this one of Jumpei Temma's superb drawings (probably also included in some of the other attached threads). IMHO the best Wildcat drawings yet published. Near the bottom are very useful comparative profiles of the three Cyclone Martlet variants.

 

http://soyuyo.main.jp/fm2/fm2e-1.html

 

YES, count me in - not that I matter... His drawings are the ONLY set (and I have looked at a couple) to feature the shallow but visible - if one takes a look or two - teardrop blister between the main spar panel line and the outboard case ejector slots on the 6-gun wing. I had a brief correspondence on this topic with Rich Dann on Hyperscale after his In Action #191 (IIRC) came out, and he stated it was not on Grumman's drawings (IIRC - it was some 16 years or so ago, and is not meant to be a take on him). But then drawings in the first Detail & Scale on the Hellcat were also based on "official" Grumman drawings I think ( @Dana Bell -correct me if I'm wrong!) and missed a full rib on the elevator. leading to a rather exaggerated tip curve. So - as great as the Grumman Historical Archives (and the incredibly-often referenced Lois Lovisolo) were - either their filing system had room for improvement, or they didn't file everything that should have been.

 

Did I say those 100-10 Martlet II's keep fascinating me? 🙂 They are the Navy's Boston III...

[NAVY870]

Can I build a Royal Navy bird from the Tamiya kit OOB or wait for Eduard?

Ta

[Troy Smith]

40 minutes ago, NAVY870 said:

Can I build a Royal Navy bird from the Tamiya kit OOB

I don't think so,  if you can only in a limited set of marking options, from my reading of this. 

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

 

 

[NAVY870]

1 hour ago, Troy Smith said:

I don't think so,  if you can only in a limited set of marking options, from my reading of this. 

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

 

 

No biggy since I do a lot of Pacific stuff.

Thanks Troy

[detail is everything]

19 hours ago, captnwoxof said:

Seeking to resolve P&W cooling/induction problems, Grumman made a number of changes. Production of G-36B fuselages resumed in the summer of 1941, and the later airplanes have features in common with the late F4F-3 and  F4F-4s that were then in production.

But the revised 3 + 1 cooling flaps arrangement was not also adopted. Also interesting that the late G-36B also adopted the internal carb air intake of the late F4F-3 and not the cowling carb air intake re-introduced for the F4F-4 and subsequent Twin Wasp variants. 

 

Why didn't the late G-36B pick up on these modifications adopted by Grumman to resolve Twin Wasp cooling/induction problems?  Perhaps, not a problem for the single stage Twin Wasp variants?

[captnwoxof]

2 hours ago, detail is everything said:

But the revised 3 + 1 cooling flaps arrangement was not also adopted. Also interesting that the late G-36B also adopted the internal carb air intake of the late F4F-3 and not the cowling carb air intake re-introduced for the F4F-4 and subsequent Twin Wasp variants. 

 

Why didn't the late G-36B pick up on these modifications adopted by Grumman to resolve Twin Wasp cooling/induction problems?  Perhaps, not a problem for the single stage Twin Wasp variants?

The carburetor and cooling problems appear to have been separate issues. What little information I have found on the problems is sketchy at best, I'm still searching for information on both.

If I understand the carburetor matter correctly, the problem was that the ducting in the cowl wasn't robust enough, and could collapse.  Replacing the external inlet with an internal inlet reduced ram entry pressure to some degree. While not necessarily desirable from a supercharging standpoint, this would have help to alleviate the problem. Ultimately, the ducting was redesigned for sturdier construction. 

The internal duct was introduced on F4F-3 BuNo. 3856. The two cowl flaps remained as before.  The eight cowl flaps were not introduced until BuNo. 3970 when F4F-3 production resumed after the F4F-3A run (BuNo. 3875-3969).

The cooling problem may well have been unique to the two-stage engine. Did the intercooler ducts restrict airflow through the cowl somehow? 

Any engineering or test reports would be very welcome. 

Edited September 24, 2022 by captnwoxof
typo

[MDriskill]

Just for the sake of keeping this thread comprehensive...other interesting former discussions squirreled away in my bookmarks:

 

Delving into the Martlet Mk II maze:

 

Interesting differences in the first Wildcat production variant - the Martlet Mk I:

 

A deep dive into technical details of Martlet paint colors:

 

Edited September 26, 2022 by MDriskill

[MDriskill]

Old guys like me...well, have a thing for actual paper. Here are four hard-copy Wildcat references that are excellent, available, and reasonably priced. I salute their authors and recommend for every F4F fan's shelf:

 

+ Richard Dann's Squadron Walk Around has a fine selection of both wartime photos and detail shots of restored machines.

+ Mr. Dann's later Squadron In Action no. 191 has the best published summary that I have seen, of the various cowl and wing details of the F4F series, much of which came directly from Grumman's historical department.

+ David Doyle's Legends of Warfare book has a large selection of superbly-printed factory photos of the US variants (no Martlets though), arranged in chronological order, including prototypes. Much on internal details of early aircraft in particular.

+ Dana Bell's Aircraft Pictorial has superbly-researched insights into history, details, and especially finishes. Much of the material came directly from the US National Archives.

 

Edited September 25, 2022 by MDriskill