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All the Wildcat/Martlet questions you wanted to ask


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1 hour ago, captnwoxof said:

I believe that the flange itself was redesigned ,being larger, heavier, and using more bolts.

Would be interesting if there's briefing notes or other documentation somewhere referring to loose intercoolers due to the rigors of deck landings.

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Maybe I'm not following but this looks like it fits the definition of a 1st Group F4F-3 and the 'damned infernal' fairing is there.  (We'll leave the problem of the twelve inch fuselage roundel for another time....)

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13 hours ago, jimmaas said:

Maybe I'm not following but this looks like it fits the definition of a 1st Group F4F-3 and the 'damned infernal' fairing is there.  (We'll leave the problem of the twelve inch fuselage roundel for another time....)

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Without seeing the BuNo I can't be sure, but it has all the features of a F4F-3A

 

Carburettor air scoop on cowling top 

Single cooling flap

Reflector gunsight

Small tear shaped fairing between wing and cowling 

Braced windscreen

later pneumatic tail wheel

 

It could be a F4F-3 1st group machine which has received mods, but I doubt it.

 

Such a machine, when manufactured would not have featured a

 

Reflector gunsight (if from first production batch)

Small tear shaped fairing between wing and cowling 

Braced windscreen

later pneumatic tail wheel

 

Edited by detail is everything
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9 hours ago, dogsbody said:

My feelings about this topic: 

 

439.gif

 

 

 

 

 

Chris

Well the similar topic for the Hurricane is on page 84 and others are even longer, so there's plenty of flogging left in this one 😀

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On 10/14/2022 at 5:32 AM, detail is everything said:
On 10/13/2022 at 5:13 PM, jimmaas said:

Maybe I'm not following but this looks like it fits the definition of a 1st Group F4F-3 and the 'damned infernal' fairing is there.  (We'll leave the problem of the twelve inch fuselage roundel for another time....)

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Expand  

Without seeing the BuNo I can't be sure, but it has all the features of a F4F-3A

The photo is in NARA, #NH97493. The uncropped original negative is USN Neg 418415, and is annotated "FAPUA 421-2-42, F4F-4". FAPUA was the Fleet Air Photographic Unit Atlantic. I don't know whether this identifies the source of the photo or the unit that the subject aircraft was serving with, but either way it seems likely that the picture was taken on the East coast in February 1942. It has the 4-gun fixed wing, and is clearly not an F4F-4.  I don't see intercooler air scoops in the cowl, indication of an F4F-3A, but I cannot definitively say that they are not there. The BuNo. is partly readable. The first digit is a 3 and the fourth is a 7. The second must be an 8 or a 9, and the third appears to be a 6, 8, or 9.  I've looked at the possible combinations.

 

3867          F4F-3  from the 19 aircraft of the second order. Service unknown (VF-41?)

3887          F4F-3A  from the first 30, requisitioned Land-lease Greek/British and served with FAA. (Martlet III).

3897          F4F-3A  from the first 30, requisitioned Land-lease Greek/British and served with FAA. (Martlet III).

3967          F4F-3A  from the remaining 65,  possibly serving with VF-5 (left behind on East coast when Yorktown redeployed to Pacific in December with VF-42 aboard).

3987          F4F-3  from the the 88 aircraft of the third order. Wrong cowl configuration (internal carb intake and 8 cowl flaps).This BuNo. served with VF-2 and was lost with Lexington.

3997          F4F-3  from the the 88 aircraft of the third order. Wrong cowl configuration (internal carb intake and 8 cowl flaps). Service unknown.

 

It is either 3867 or 3967. My guess is F4F-3A 3967, but its just a hunch.

Edited by captnwoxof
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A reply from the USN Museum, verbatim,

 

You asked, "Do the aircraft history cards for BuNos 3856 to 3874 give the engine as R-1830-76 or R-1830-86?" I checked all Bureau Numbers between 3856 and 3874, and they all list Engine Model R-1830-76.  Additionally, BuNos 3861 & 3862 have "2 stage" handwritten next to the typed engine model number. BuNos 3863 and 3864 have "(2)" handwritten next to the engine number.

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20 hours ago, captnwoxof said:

The photo is in NARA, #NH97493. The uncropped original negative is USN Neg 418415, and is annotated "FAPUA 421-2-42, F4F-4". FAPUA was the Fleet Air Photographic Unit Atlantic. I don't know whether this identifies the source of the photo or the unit that the subject aircraft was serving with, but either way it seems likely that the picture was taken on the East coast in February 1942. It has the 4-gun fixed wing, and is clearly not an F4F-4.  I don't see intercooler air scoops in the cowl, indication of an F4F-3A, but I cannot definitively say that they are not there. The BuNo. is partly readable. The first digit is a 3 and the fourth is a 7.

If the first 19 aircraft of the second order (Bu. Nos. 3856-3874) had no tear-shaped fairing in front of the wing, this rules them out for this photo. The blue-grey upper surface colour appears to be a later addition, I'd think that the aircraft was originally in light "neutrality" grey overall, which would explain the position of the fuselage star roundel. The small fuselage fairing remained in light grey, whereas on factory-finished aircraft the blue-grey extends much lower. Considering all the features, I agree with @detail is everything and @captnwoxof that an F4F-3A is most likely. Then, the second digit in the Bu. No. "has to be" a '9'. I do see a '7' as the final digit, too.

Combining informantion from Lundstrom's "The First Team" and a crash list, here's what I found:

3907        with VF-6 on Enterprise in November 1941, lost at sea December 31, 1941

3917        with VF-6 on Enterprise in November 1941

3927

3937        with VF-6 on Enterprise in November 1941, crashed February 1, 1942 during night launch

3947        with ACTG/A (Advanced Carrier Training Group, Atlantic), lost 25 November 1941, Isle of Wight, VA

3957        with VF-2 on Saratoga in February 1942

3967        with VF-2 on Saratoga in February 1942

On the photo the third digit is a rather indistinct blob, '2' might perhaps also be possible.

 

VF-5 is definitely a possibility, IMHO. For the fuselage code, I am in doubt between F-5 and F-9.

Edited by ClaudioN
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On 10/13/2022 at 3:03 PM, detail is everything said:

After further discussion here, I concluded that the 2nd F4F-3 group of 19, were powered by the -76 engine and not as Detail and Scale Vol 7 stated the -86 engine. Also that they were produced before the F4F-3As. As discussed above the lack of intercooler clearance fairings on these machines, seem to reinforce that theory.

 

You now appear to be saying that they were powered by the -86 and they were manufactured after the F4F-3As.

Sorry for creating the confusion. I emphasized then that it was my guesswork, and I still keep guessing...

This post by @Dana Bell may help clarify.

 

This photo shows an F4F-3 of VF-8 without the small bulge on the fuselage forward of the wing and no carburettor intake on the cowling ring. Might be one of the 19?

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SDASM Archives, Public domain, via Wikimedia Commons

 

Although Wikimedia Commons refers to the SDASM Archives (Ray Wagner Collection), the photo is credited to the US Navy on Profile no. 53, where it appeared many years ago. I was unable to find it on the https://www.history.navy.mil/ web site, although I expect it should be within their collections. If it's there, there could be a high-resolution .tiff file and we might have a guess at the tiny Bu. No. on the fin.

 

Question for experts: what is that straight 'pole' sticking out of the fuselage, mid-way between the antenna mast and the fin?

 

Edited by ClaudioN
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3 hours ago, ClaudioN said:

I'd think that the aircraft was originally in light "neutrality" grey overall, which would explain the position of the fuselage star roundel.

Just to simplify matters, all F4F-3's were originally delivered in Non Specular Light Gray.  The NS Blue Gray was applied at unit or depot level.  

 

Both the position and size of the twelve inch roundel are non-standard.  This non-standard roundel appears on F4F-3's with, and without, the small fuselage bulge between the leading edge and cowling (which maybe we should call 'Bob' for ease of reference).

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5 hours ago, jimmaas said:

Both the position and size of the twelve inch roundel are non-standard.

Thank you, I did not realize it until now.

On photos I have, I can see the small roundel only on aircraft of VF-41, VF-71 and VF-5. Maybe it could somehow be related to carriers in the Atlantic Fleet?

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 A new twist in the "blister" saga.

The first rule of research is never make assumptions. I had assumed that the addition of a blister to the forward fuselage panel was a reflection of some alteration immediately beneath it, and that the panel itself was otherwise identical. It is not! The panel itself is dimensionally different, Aircraft without the blister all have a different style of firewall, and the panel is "shorter" at the forward edege where it fastens to it. Once I found what to look for, it's unmistakable. The firewall on the early aircraft (without blister) has a rounded profile. The rear of it is aft of the rear edge of the cowl.

 

y4mvEPs7jRIiQx36bLDMNt23ifKy-poXb-7EBjpG

 

On aircraft with the blister, the firewall is shorter in cord and less rounded. There is no joint line visible, since the aft edge is in line with the aft edge of the cowl.

 

y4mQoBPXMuhxPXaA9bulbCsZhs8dvzQbXGcgILwN

 

I have gone through my references. In every example, I find that the blistered panel is fitted to aircraft with the later style firewall, and never to aircraft with the earlier style. This holds true for all P&W powered varients, regardless of what engine was installed. This suggests that (for some reason) it was found necessary to alter the design of the firewall, requiring that the panels aft of it be revised, and that this caused some sort of interference between the intercoolers and the panels. The change was in the panels, rather than the intercoolers. 

I have no idea what necessitated the alteration to the firewall.. Any input or information from others would be very welcome.

 

(You may have to uplink the photos as files. I apologize, I still don't have a good method of embedding. If you can't access them, look at the photos in the Bell, Dann, or Doyle books.) 

Edited by captnwoxof
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Good spot! A change in firewall arrangement necessitating the introduction of the blistered panel, as an incremental change would explain why the F4F-3A had the blistered panels, despite not having an intercooler and being built several months before the introduction of the -86 engined F4F-3. Basically the new firewall arrangement and associated blister was introduced by the F4F-3A.

 

However, this picture causes me a problem.  If we are saying the relevant nose panels were of different dimensions, depending on which firewall arrangement was used, this picture would appear to show some unblistered panels on machines with the later firewall arrangement (I can't see a difference between the machines, can you?)

 

EF0-DDAEC-5-E30-41-C4-89-F2-CE655-DA4-B0

 

If you ignore the differing dimensions issue, the fact that some very early AM#### serial Martlet IIs didn't have the blistered panel, despite being completed with folding wings after the F4F-3As, can be explained away by the fact that the very earliest fuselages were probably built from components which originate from December 1940, before the F4F-3As were built between March and May 1941.  This is because construction of the Martlet II was was stopped after the first 10 machines were built and completed as fixed wing Martlet III(A)s. 

 

Already delivered components would have been stored, ready for when production of the remaining 90 machines would have resumed between August and December 1941, once the folding wings were ready to be fitted.  Lots of assumptions but I'm guessing the stored components were for the earlier firewall arrangement and then, as the Martlet II build continued, the delivered components would have incorporated the by now new firewall arrangement. However the photo above doesn't show a mix of early or revised firewall arrangements, so my hypothesis is flawed unless someone can explain away the above photo. 

 

One last thought. Was the blister on -90 engined machines, slightly smaller than on  -86 engined machines? A comparable photo of an F4F-3A machine (with original panels) would quickly sort that query out.  You would have to be certain that the F4F-3A machine had its original blistered panels as they may have been replaced ,whilst in service or when being restored, by -86 engine blistered panels which I think would fit given they shared the same revised firewall arrangement. 

Edited by detail is everything
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The different-length side panels is a brilliant observation! Thanks much for that - VERY interesting (and apologies for this nitpicking, but the "firewall" is the aft face of the accessory/landing gear bay - not the engine mounting bulkhead).

 

Pure speculation on my part, but the longer side panels and intercooler blister seem to be separate issues. As noted per the above photo, the early Martlet II's look to have had the former without the latter (though this didn't last long - as noted earlier, perhaps just to eliminate stockpiling different versions of this simple component).

 

Looking at photos of engines, etc., while the longer panel did create room to place the blister, it also improves access to the accessory bay (the earlier bulkhead lapped over the intercoolers a bit); and looks to have been a simpler, lighter assembly.

 

DE910-AB4-CC35-4871-AED8-173925-B9-C7-E1

 

23-A1271-C-6-E0-C-4-D4-D-AE49-C508-FA16-

 

 

Edited by MDriskill
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This thread is a goldmine for an amateurish Wildcatista like me!

A first thought that crossed my mind was CoG - if some weight up front is deleted, it would make sense to move an ostensibly relatively heavy part like the mounting bulkhead forward a bit to compensate. But if that bulkhead applies to all P&W versions from some point on - -3, -3A, -4, FM-1 and Martlet II - then probably not. Possibly "only" a move to introduce a lighter structure to gain some kgs in comparison with the A6M, while improving access to the accessory bay?

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Great find!

Your result suggests that, whereas rivet counting may perhaps be considered excessive nit-picking, counting panel fasteners definitely pays!

Inspired by your post, I spent several hours over the weekend doing almost just that, and comparing photographs.

 

Here's what I may have found.

 

1) NUMBER OF FASTENERS ON THE UPPER PANEL THAT COVERS THE ENGINE ACCESSORY BAY

                                                                                   early F4F-3        late F4F-3A and late F4F-3        G-36A

bottom edge, in front of the wing leading edge:         two                                   three                           three

upper edge, below the m/g panel                                 six                                    seven                          seven

 

Of course, accessory bay panels are shorter on early F4F-3s because of the different shape of the engine frame ("firewall"). What is interesting, is that on a F4F-3A and a G-36A they are the same length (yes, they are: distances between fasteners do not change).

This revived my feeling that the XF4F-6 was no more than a G-36A fuselage with a R-1830-90 grafted on and a F4F-3 cowling applied.

 

2) IS THERE ANY RELEVANT DIFFERENCE BETWEEN ENGINE VARIANTS?

Pratt & Whitney "index of Twin Wasp & R-1830 designated engines" gives three different engine lengths:

  • R-1830-76 length: 71.31 inches
  • R-1830-90 length: 63.41 inches
  • R-1830-86 length: 67.44 inches

Unsurprisingly the single-stage R-1830-90 is "shorter" by nearly 8 inches than the two-stage R-1830-76. This might be irrelevant, but it suggests that some engine parts/accessiories might be located furter forward, making the -90 compatible with the G-36A engine frame.

 

3) ARE THE R-1830-76 AND R-1830-86 INTERCHANGEABLE?

That is: can we fit a -76 into a "late style" forward fuselage? Big question and little evidence to check for, BUT:

  • the 19 F4F-3s Bu. Nos. 3856 to 3874 are confirmed as having the R-1830-76
  • they also had the revised carburettor intake within the cowling ring

What it takes to attempt an answer is to find evidence of "early style" panels on a machine with "late type" cowling. Well, here it is (photo of 8-F-1 already posted above, repeated here for convenience):

spacer.png

SDASM Archives, Public domain, via Wikimedia Commons

 

The vertical panel line right behind the cowling, associated with the "-76 style" engine frame is clearly discernible.

The answer I would give is then: -86 is not interchangeable with -76. The proper engine frame is needed to fit the -76 version.

 

My take on F4F-3 variations

Here I try to suggest a sequence of steps that in my view can have some engineering sense, reducing changes and production variations to a minimum.

  1. F4F-3 with the R-1830-76 evidences teething troubles related to engine cooling
  2. G-36A first flies in May 1940, with less trouble but significantly less performance, as found with the XF4F-5
  3. G-36B first flies in October 1940, also with less trouble but generally good performance, leading to an evaluation order for the XF4F-6
  4. F4F-3s from the first order are delivered, but problems arise with the carburettor intake mounted on the cowling upper lip
  5. production of a further 19 F4F-3 with the R-1830-76 is temporarily stopped, pending a redesign of the carburettor air intake
  6. Pratt & Whitney are further developing their two-stage supercharged Twin Wasp into the -86 version. Grummans realize that the -86 can fit where the -90 fits: all it takes is a small bulge on the lower panel fitted over the engine accessory bay
  7. production shifts to aircraft with the single-stage R-1830-90: British fixed-wing G-36Bs (flat panel) and 95 F4F-3As (small bulge on panel). Seemingly, these aircraft do not have the same carburettor intake problems as those with the two-stage engine, as the original external intake is retained
  8. the new cowling design becomes available and is fitted to the 19 F4F-3s whose production is resumed. They retain the single cooling flap on the cowling, like the G-36Bs and F4F-3As
  9. the R-1830-86 is introduced and, with it, the new cooling flap arrangement having four smaller flaps per side. The redesigned cowling with internal carburettor intake is retained
  10. after all F4F-3s are delivered, production shifts to folding-wing G-36Bs (single cooling flap per side, "late F4F-3" cowling shape) and the F4F-4 (four cooling flaps per side, new "F4F-4 style" cowling with redesigned and strengthened external intake

Sounds convining enough to me, over to BM friends' opinions.

 

Claudio

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Again I'm running off photos and semi-educated guesswork in lieu of factory documentation here, but I think the overall engine lengths must include the accessories extending aft through the mounting bulkhead. The heavy bits (cylinders and crankcase) are located the same relative to the rest of the airframe for the -76, -86, and -90 (and are not over 5 feet long).

 

The list sounds great to me! But its "No. 11" could be that last batch of weird F4F-3 trainers discussed above...really "dash 4's" in all respects save the wings.

Edited by MDriskill
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14 hours ago, detail is everything said:

If you ignore the differing dimensions issue, the fact that some very early AM#### serial Martlet IIs didn't have the blistered panel, despite being completed with folding wings after the F4F-3As, can be explained away by the fact that the very earliest fuselages were probably built from components which originate from December 1940, before the F4F-3As were built between March and May 1941.  This is because construction of the Martlet II was was stopped after the first 10 machines were built and completed as fixed wing Martlet III(A)s. 

 

Since my last post, I have been going back through references, trying to determine the rhyme and reason for the altered design of the engine mounting bulkhead (that I dorked and called a firewall, i really do know better). So far the search has revealed as many questions as answers. You zeroed in on a discrepency I havent been able to resolve yet. While the combination of bulkhead/panel construction shows a consistent pattern for US Navy F4F production. the G-36Bs fell outside of this and reveal anomolies, Some examples in the early AM serial range did not have the blister. What bulkhead was fitted? I spent the weekend looking for answers, re-examining photos and comparing the time line of F4F-3/3A and G-36B production.. I am reluctant to make guesses where I haven't found certainties, the waters are muddy,but here is what I have so far. 

 

The earliest example of the revised engine mounting/side panel construction that I have found is the XF4F-6. Both the USN and the British displayed Interest in a single-stage R-1830 powered version I don't know which came first,. The British specified this engine for the 100 G-36B s in July 1940, at about the same time (date unspecified) that the USN  ordered a single additional airframe fitted with the military version of the same engine. Designated the XF4F-6, it was completed before G-36B production began so it would appear to have been the prototype for the single stage engine installation. It first flew in October 1940, and was delivered in November. Photos are few, the best resolution I have found is in Doyle's Legends of Warfare, pg 47. It had the "late" style bulkhead and "extended " side panels. However, the panels do not have the blisters. There were no intercoolers  so they weren't necessary. The entire setup suggests to me that the firewall and panels were altered as a reflection of the change of engine, perhaps in order to take the opportunity to simplify structural components that no longer were required to accomodate the intercoolers. This is strictly hypothetical, the change may have been for an entirely  different reason.

7 hours ago, ClaudioN said:

2) IS THERE ANY RELEVANT DIFFERENCE BETWEEN ENGINE VARIoANTS?

Pratt & Whitney "index of Twin Wasp & R-1830 designated engines" gives three different engine lengths:

  • R-1830-76 length: 71.31 inches
  • R-1830-90 length: 63.41 inches
  • R-1830-86 length: 67.44 inches

 

Claudio has speculated that dimensional differences might have been the cause for the redesign. I believe that the dimensional differences quoted were due to differences in the  accessory sections of the engines, and that the crankcase was mounted to the bearers in the same position for all  models. However, that doen't rule out changing the bulkhead in order to give more space for the accessories, and this may have been the case.

 

The first 10 G-36B fuselages (AM954-963) were constructed in December 1940. Construction of their folding wings was delayed, so the fuselages were placed in storage. They were eventually fitted with fixed wings and delivered in March, but a lot of production changes occurred in the interim. Again, photos are rare, but they appear to exactly mirror the XF4F-6, with the "late" firewall and extended panels without blisters

 

Further construction of G-36B fuselages was suspended for six months until the folding wing was ready for production. 

 

From this point, more questions than answers arise.

The USN decided to install the single-stage engine in 95 F4F-3 airframes, redesignating them F4F-3A.  Construction began in February 1941. All of them (BuNo 3875-3969) were built with the revised bulkhead /side panel arrangement of the XF4F-6, except the side panel has the blister. Why? It isn't necessary. it has been suggested that it was for commonality with F4F-3 production, and this seems likely, but it raises another question:  When did the two-stage engined airplanes adopt the new style of bulkhead and forward panels,, and why? Doing so required the introduction of the blisters, they were neccessary to clear the intercooler flange..Commanality of construction? Was there something that made the revised bulkhead preferable (or required) for all R-1830 powered versions? 

 

The last F4F-3 of the first order (BuNo 2538) left the factory on February 21, 1941. It was -76 powered, and had the early "rounded" bulkhead/plain panel arrangement.

The first 19 F4F-3s of the second order (BuNo 3856-74) are a mysterious lot. Their BuNos preceded those of the -3As, and it has been suggested that they were built concurrently, but delivery was delayed due to lack of (or trouble with) their  -76 engines. Their cowling configuration was altered, but what the bulkhead/side panel arrangement was used in their construction? Original or revised?

After the last -3A was delivered, -3 construction resumed in June with BuNo 3970. From this point, all subsequent P&W powered F4F/FM-1 production had the -86 engine. All had the revised bulkhead, with the blistered side panels.

 

What about the 90 remaining G-36Bs? Construction recommenced in June. All 90 had the revised bulkhead. Some of the first airframes (AM964 and AM 966 are known examples) had side panels without blisters. It has been speculated that these were panels fabricated back in December before a decision was made to standardize on producing all panels with blisters, and they were used because they were available. This explanation is reasonable and logical (and so it should be regarded with great suspicion 🤨!

 

Thanks to all who are chiming in. Sometimes if you flog a dead horse enough, it makes a comeback, wakes up and does something useful..🙂

 

 

 

Edited by captnwoxof
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Food for thought...

I agree the overall length includes the accessories, I was not clear about it. Indeed, what is interesting for our discussion is that the two-stage -86 is also shorter than the two-stage -76, by nearly 4 inches. I assume this to be a result of some relocation of accessories (the front-positioned magnetos that are always mentioned as a hallmark of the -86 come to mind, but I really do not know!). Whether this has something to do with the revised bulkhead I really do not know.

 

Just a few questions added:

  • side panel with/without blister: I would think there was a commonality with the G-36A and some "flat" panels for the G-36B could keep coming from that production line?
  • agreed Bu. Nos. 3856-3874 are a mysterious lot. My idea is that 8-F-1 (and several F4F-3s of VF-8 photographed on USS Hornet in February 1942) come from that lot. What do you people think?
  • what does "construction starts" actually mean? I may be mistaken, but I seem to recall construction numbers (and, I would think, Bu. Nos. as well) are associated with an aircraft fuselage. Several photos show that fuselages were stored in Grumman hangars waiting for their wings. Perhaps this might explain the discrepancies between construction and delivery dates?

Claudio

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15 hours ago, ClaudioN said:

Of course, accessory bay panels are shorter on early F4F-3s because of the different shape of the engine frame ("firewall"). What is interesting, is that on a F4F-3A and a G-36A they are the same length (yes, they are: distances between fasteners do not change).

 

4 hours ago, ClaudioN said:

side panel with/without blister: I would think there was a commonality with the G-36A and some "flat" panels for the G-36B could keep coming from that production line?

Hi Claudio

Thanks for the feedback, you've given me several new insights to pursue. But as to the commonality of G-36A side panels, I have to disagree. They are not the same length. You are correct about the number of fasteners, but the distance between them did change. The engine mounting bulkhead was further forward because the lighter single row Wright engine had to be mounted further forward for CG considerations.

Please look at the following comparison between the FAA Museum Martlet I and a P&W installation with the panels removed. On the Martlet, you can see the "extension" of the framework that runs from the leading edge to the engine mount bulkhead.

y4mcHtOFG77nLGaL02_Lmufj84Jjgv_sIWMWblXd

 

y4mh10NfhsHEI5sZz8IYxkoPElqK5KtZ5A1wLjOG

 

Hope this helps.

 

The three Wright powered varients (Martlet I, Martlet IV, Martlet VI) were each unique. However, while the Martlet I and IV had different subvariants of the engine and their cowls were different, AFAIK the engine position was identical on these two marks. So they would appear to have used identical fuselage side panels, but I haven't looked into it enough to say that for certain.

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Excellent observations! Also, take a look back at Mr. Temma's Martlet I - IV -VI profiles earlier in the thread for various Cyclone cowls.

 

Not only was the Cyclone mounted further forward than the Twin Wasp, but it was about 6 inches bigger in diameter. Both were centered on the same longitudinal fuselage datum, so all fuselage panels forward of the firewall are necessarily subtly different.

 

Mr. Temma's cross section drawings show this well, though the Wildcat's chubby teardrop of a fuselage absorbed both engines so well that the difference in exterior appearance is subtle.

 

http://soyuyo.main.jp/fm2/f4f4_cross

 

http://soyuyo.main.jp/fm2/fm2_cross.gif

Edited by MDriskill
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8 hours ago, captnwoxof said:

Hi Claudio

Thanks for the feedback, you've given me several new insights to pursue. But as to the commonality of G-36A side panels, I have to disagree. They are not the same length. You are correct about the number of fasteners, but the distance between them did change. The engine mounting bulkhead was further forward because the lighter single row Wright engine had to be mounted further forward for CG considerations.

Please look at the following comparison between the FAA Museum Martlet I and a P&W installation with the panels removed. On the Martlet, you can see the "extension" of the framework that runs from the leading edge to the engine mount bulkhead.

y4mcHtOFG77nLGaL02_Lmufj84Jjgv_sIWMWblXd

 

y4mh10NfhsHEI5sZz8IYxkoPElqK5KtZ5A1wLjOG

 

Hope this helps.

 

The three Wright powered varients (Martlet I, Martlet IV, Martlet VI) were each unique. However, while the Martlet I and IV had different subvariants of the engine and their cowls were different, AFAIK the engine position was identical on these two marks. So they would appear to have used identical fuselage side panels, but I haven't looked into it enough to say that for certain.

Photos not showing, either here or Firefox, which is a pity as I've been really enjoying this thread as a Wildcat enthusiast from waaaaay back. So much stuff I've not seen before in it.

Steve.

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Just a note re modelling the Eduard F4F-3 - The propeller boss as given ends in a flat front, which is incorrect; it should be hemispherical.  Easy fix depending on your stash:  the Airfix 1/48 P-40B/C kit has a propeller which had a perfectly shaped boss for the purpose, and which in no way would be seen on a finished model if the spinner is fitted.  Just slice the Eduard boss off, slice the Airfix boss from the prop and glue to the Eduard part.   

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