F4F-4 Wildcat length

[warhawk]

Hello,

 

I came across THIS article, by a modeller who always draws scale plans himself, based on his research.

He states that the total length of FM-2 Wildcat can be proven, but the the total length of F4F-4 had to be estimated...

 

Could anyone with access to original F4F-4 factory documentation please check these measurements for me, preferably in metric units (please see attached image):

a ) front to back of cowling length

b ) back of cowling to windscreen length

c ) windscreen to front of "hump" length

d ) front of "hump" to rudder hinge line length

 

 

Thanks in advance!

 

 

 

 

Edited July 14, 2018 by warhawk

[Work In Progress]

Given that official factory documentation very often varies significantly from what the factories actually built, it would be even better to get some competent measurements taken direct from the surviving F4F-4 airframes, all of which are in the USA. Sadly here we only have examples of the FM-2, plus the Martlet I at Yeovilton

Edited April 13, 2017 by Work In Progress

[Graham Boak]

If you work from the PR handouts, rather than the actual drawings from which the tools were made, then you can find variations from the build standard.  Otherwise you should be ok.  I gather that a modern problem with research into US types is that the original US companies have now merged, so that what once were very helpful company libraries/librarians no longer exist.

 

The examples in the UK should at least provide the correct dimensions for c and d on the sketch.

[tempestfan]

Most if not all of the references quoted in that marvellous article have drawn on the assistance of the Grumman Historical Archives/Lois Lovisolo. That probably means different drawings quoting different dimensions were provided. One aspect I hope I do not ride to death is that the drawings by our Japanese friend are the ONLY  ones I know of that correctly show the shallow teardrop fairings in front of the outboard case chutes, which leads me to deduct the official Grumman drawings don't. IIRC Richard Dann (author of the second in action and Walk Around ) confirmed this way back when on the HS forum. This in turn suggests that all commercial drawings have been based on generic GA's and not engineering drawings. Possibly the latter simply don't exist anymore. Even if they do, I have no idea what happened to the contents of the GHA upon its closure, and if anyone could locate them. After all, they're just some stinkin' old sheets of paper no one needs. ..

[ClaudioN]

This:

http://www.britmodeller.com/forums/index.php?/topic/234929183-martlet-mki/

might help work out values for distances 'c' and 'd', but not for 'a' and 'b'.

Scroll down the page and you'll find a quoted (in inches) fuselage profile with all stations from 2 onwards, that is, from the engine firewall to the rudder post.

 

Personally, I do trust scale drawings by Jumpei Temma.

Edited April 13, 2017 by ClaudioN

[warhawk]

31 minutes ago, ClaudioN said:

Personally, I do trust scale drawings by Jumpei Temma.

 

Given the amount of his research, I do too.

But that means that both 1/72nd Hasegawa and new-tool Airfix F4F-4 are considerably shorter than they should be...

[Graham Boak]

How do the dimensions he calculates differ from those given in the GA drawings M Driscoll shows in this thread, and what is the justification for any difference?

 

The statement I find slightly surprising is that the firewall for the Cyclone and for the Twin Wasp variants are said to be the same,  I can see how this would be ideal for production, but I thought that the aircraft was designed for the Cyclone, which is the shorter of the two engines.  Placing the Twin Wasp ahead of the same firewall would considerably increase the length of the aircraft.  What we actually  see is a reduction in the length of the fuselage between the engine cowling and the wing.  This suggests that the Cyclone variant must have been designed with longer engine mountings than it actually required, and considered by itself this is odd.  It could be, of course, that the aircraft was designed to be able to take both.

 

However, Jumpei Temma shows Hasegawa's fuselage against his plans, and there's no sign of the kit being any longer.  

[ClaudioN]

1 hour ago, Graham Boak said:

The statement I find slightly surprising is that the firewall for the Cyclone and for the Twin Wasp variants are said to be the same,  I can see how this would be ideal for production, but I thought that the aircraft was designed for the Cyclone, which is the shorter of the two engines.  Placing the Twin Wasp ahead of the same firewall would considerably increase the length of the aircraft.  What we actually  see is a reduction in the length of the fuselage between the engine cowling and the wing.  This suggests that the Cyclone variant must have been designed with longer engine mountings than it actually required, and considered by itself this is odd.  It could be, of course, that the aircraft was designed to be able to take both.

 

However, Jumpei Temma shows Hasegawa's fuselage against his plans, and there's no sign of the kit being any longer.  

 

The XF4F-3 was designed for the R-1830 and I think you are right thinking that the Cyclone engine mountings were "longer than needed" (probably, long enough to preserve balance).

I have no experience of the Hasegawa F4F. The Airfix one, IMHO, is just 1-2 mm short, if you wish to care about. My feeling is that the difference is concentrated between the wing leading edge and the cowling, so it may be noticed by a keen eye, but it can also be easily modified, if needed.

[Gwart]

There's this http://ulsteraviationsociety.org/wildcat-f4f

 

 

Edited April 13, 2017 by Gwart
added a pic.

[Bruce Archer]

Hi All!

    When I wrote my article (http://www.clubhyper.com/reference/wildcatfaaba_1.htm

I  found the Martlet/Wildcat was the same length, regardless of engine. The Cyclone cowls are shorter, but the length between the wing leading edge and the rear of the cowl is longer, and conversely aircraft with the longer P&W cowl have a shorter length between the wing leading edge and the rear of the cowl. The reason was the Cyclone needed to be mounted further out due to CG issues.

 

Bruce

[Procopius]

13 minutes ago, Bruce Archer said:

Hi All!

    When I wrote my article (http://www.clubhyper.com/reference/wildcatfaaba_1.htm

I  found the Martlet/Wildcat was the same length, regardless of engine. The Cyclone cowls are shorter, but the length between the wing leading edge and the rear of the cowl is longer, and conversely aircraft with the longer P&W cowl have a shorter length between the wing leading edge and the rear of the cowl. The reason was the Cyclone needed to be mounted further out due to CG issues.

 

Bruce

 

That's a terrific article, by the way. Really helped me make sense of the variants.

[Work In Progress]

An excellent summary indeed by Bruce, definitely one for the archive

[Graham Boak]

Claudio: in the early stages designers don't mount the engine further forward than necessary: if the balance is a problem they move the wing.  This is obviously much more difficult once the design is set into metal.  (Witness the problem with the Stirling's take-off distance, where it proved easier to design that Heath Robinson of an undercarriage rather than increase the incidence of the wing.)  So either the design was originally laid out for the P&W, or for the option of both.  There is perhaps another route.  It was designed initially as a biplane, so maybe it was easier to keep most of the fuselage design when changing it to a monoplane, but I'm not convinced that the load paths would be strong enough.

 

PS  It occurs to me that perhaps this is a feature of radial-engined fighters, at least in the 30s.  There just was empty space behind the engine, so fitting a longer engine wasn't the same problem as it was to a more tightly packaged inline.There was also less in the way of auxiliaries behind the engine that there was to be in a later generation.  Fitting the engine as close as possible perhaps gave an airframe that was too short-coupled for comfortable handling.  (e.g. I-16 and later Polikarpov fighters).  Aargh, too many unknown variables.

Edited April 14, 2017 by Graham Boak

[warhawk]

Thank You for great explanations of length from an engineering standpoint.

 

13 hours ago, Graham Boak said:

However, Jumpei Temma shows Hasegawa's fuselage against his plans, and there's no sign of the kit being any longer.  

 

He did not. Those were Tamiya 1/48, and Airfix 1/72 fuselages. No image for Hase fuselage.

He also states: 

The total length is the same as FAOTW. So the length is shorter than my estimation by about 3mm (0.1")

 

Another review I have found compares Hasegawa and AIrfix:

The two models match up almost exactly to each other in terms of dimensions, and these match published dimensions.

 

Soooo.... Either both are correct or both are wrong, I guess...

 

 

[Gwart]

Neither are 100%.

[Greenshirt]

2 hours ago, Graham Boak said:

the option of both

This.  I've read numerous histories of USN carrier aircraft designs of the '30s wherein the USN wanted options, so specified the basic design must accommodate two different engines so the testers could determine the best engine-airframe combination...and to leverage the better engine designs as they matured in parallel to the airframe development. 

 

When the government can can afford this, it makes great sense given the rapid development of aircraft of the time. 

[MDriskill]

On April 13, 2017 at 10:56 PM, Bruce Archer said:

Hi All!

    When I wrote my article (http://www.clubhyper.com/reference/wildcatfaaba_1.htm

I  found the Martlet/Wildcat was the same length, regardless of engine. The Cyclone cowls are shorter, but the length between the wing leading edge and the rear of the cowl is longer, and conversely aircraft with the longer P&W cowl have a shorter length between the wing leading edge and the rear of the cowl. The reason was the Cyclone needed to be mounted further out due to CG issues.

 

Bruce

 

To phrase this excellent summary another way: the single-row Cyclone was shorter than the twin-row Twin Wasp, and also significantly lighter (most versions of the latter used in the F4F had a 2-stage supercharger and bulky intercoolers, in addition to a longer crankcase and more cylinders).

 

So the Cyclone had to be mounted further forward, and its cylinder bank ended up in about the same spot as the Twin Wasp's front cylinders. Looking at it that way, the airframe inevitably had to be about the same length with either powerplant.

 

Both engines had relatively long mounting frames, since not only the engine accessory section but the entire landing gear mechanism fit between the engine and the firewall. The basic fuselage structure from the firewall aft to the tail post actually stayed the same throughout F4F production.

 

To answer one of the OP's original questions, the excellent recent book on the Wildcat by Dana Bell contains many of the dimensioned fuselage drawings from the type's erection and maintenance manuals. Finally let me add that I certainly agree the Jumpei Temma's drawings are the best out there at the moment; his research methodology and thoroughness are amazing.

Edited April 15, 2017 by MDriskill

[Seahawk]

On 14/04/2017 at 11:02 AM, warhawk said:

Another review I have found compares Hasegawa and AIrfix:

The two models match up almost exactly to each other in terms of dimensions, and these match published dimensions.

Soooo.... Either both are correct or both are wrong, I guess...

 

I have the greatest of respect for Chris Bucholtz, I like that style of review and he raises several interesting points in the review in question.  However the first part of the highlighted sentence is simply not true if the words mean what I understand them to mean in normal English usage.  There was a very long thread when the new Airfix F4F-4 came out highlighting problems with both AX and HA kits.  The upshot is that the Airfix kit is about 1-1.5mm too portly and the Hasegawa kit too slender by about the same margin.  So both are wrong.  If Chris's assertion were true it would be possible to make the Hasegawa canopy (and aftermarket replacements) readily fit the Airfix kit, thereby correcting one of the most egregious errors of the AX kit.  Sadly it isn't: the Airfix fuselage spine is too wide and too low.

 

BTW I have looked for that original thread on the Airfix F4F-4 and its competitors and can't find it (though I can find allusions to it).  If anyone can find it, please post a link to it so we don't keep reinventing the wheel every time the accuracy or otherwise of the AX F4F is discussed.

[gingerbob]

 

23 minutes ago, Seahawk said:

BTW I have looked for that original thread on the Airfix F4F-4 and its competitors and can't find it

 

Possibly this one?  Much talk, dimensions tossed about, but it seems that the useful photos (if they were) are no longer showing.

 

Here's another take on the comparison.

[Seahawk]

10 minutes ago, gingerbob said:

 

 

Possibly this one?  Much talk, dimensions tossed about, but it seems that the useful photos (if they were) are no longer showing.

 

Here's another take on the comparison.

 

Looked at that one.  Possibly (maybe it makes less sense without some of the photos) but I think not.  ISTR someone demonstrating convincingly that Airfix had unfortunately made the old mistake of trusting data from the manufacturer, basing their kit on drawings supplied by Grumman (or their heirs and successors) which showed an early prototype with different fuselage contours. 

 

The second take is the one warhawk cites and with which I was disagreeing (see offending sentence in section 3 Fidelity of Outline).

[Bruce Archer]

Hi Again!

    My statements are based on actual measurements of :

Martlet I at the FAA Museum

FM-1 at the Smithsonian Air and Space Museum

FM-2 at Stallion 51, Kissimmee International Airport, Kissimmee Florida

 

All were measured from the wing leading edge, to the rear of the cowl, then to the front of the cowl. All had the same measurement from the wing leading edge to the rudder post.

 

Bruce

[ClaudioN]

On 14/4/2017 at 2:10 PM, Greenshirt said:

I've read numerous histories of USN carrier aircraft designs of the '30s wherein the USN wanted options, so specified the basic design must accommodate two different engines so the testers could determine the best engine-airframe combination...and to leverage the better engine designs as they matured in parallel to the airframe development.

AFAIK, on the F4F the USN did want the 14-cylinder R-1830 with a two-speed, two-stage supercharger. Alternative engines were considered by Grummans for two reasons:

1. the French export order in 1939, for which the Wright Cyclone was offered
2. persisting development troubles with the two-stage supercharger, that led the USN to consider trials with two alternative, less complex engines:

• the Wright R-1820 Cyclone, for which two early airframes of the initial F4F-3 order were modified into XF4F-5s (earlier versions of the Cyclone already powered Brewster F2As, Grumman F3F-2s and F3F-3s)
• the single-stage Pratt and Whitney R-1830-90 Twin Wasp, for which a single prototype XF4F-6 was ordered, followed by stop-gap production of the F4F-3A

I believe design work for the Cyclone powerplant was related to the French order. Curiously, things had gone the other way round with the previous F3F, where the 14-cylinder, two-row P&W R-1535 Twin Wasp Junior of the F3F-1 was replaced by the single-row Wright R-1820 of the later F3F variants, with minimal difference in overall length.

[Greenshirt]

19 hours ago, ClaudioN said:

I believe design work for the Cyclone powerplant was related to the French order. Curiously, things had gone the other way round with the previous F3F, where the 14-cylinder, two-row P&W R-1535 Twin Wasp Junior of the F3F-1 was replaced by the single-row Wright R-1820 of the later F3F variants, with minimal difference in overall length.

So for the F4F it appears Grumman was forward looking to alternative power plants, given their experience with USN on previous designs, and interest from foreign governments. Which paid nice dividends later in the various marks, and in the final FM-2 variant. 

 

The dry weights of the basic power plants are only about 66 pounds different, with the Cyclone being lighter, so in terms of weight and balance I could see the prop assembly located in the same location on the design thrust line of the F4F with some sort of offset aft of CG as appropriate for specific configuration. 

[dragonlanceHR]

To the subject of drawings by Jun Temma, I had some correspondence with him regarding the Yak and LaGG technical manuals and original drawings, and he uses the original manufacturers data, esp. the ordinate tables, whenever possible.

 

As to his research, he is very observant and meticulous. He even re-discovered the different F8F windshields :-)

 

Vedran

[ClaudioN]

14 hours ago, Greenshirt said:

So for the F4F it appears Grumman was forward looking to alternative power plants

The practice appears to have been common till the late 'thirties. Think of the radial-engined Hawker Hart export variants, for instance.

To pursue a sale to the Romanian air force, Savoia-Marchetti in Italy went as far as turning their S.79 tri-motor into a twin with in-line Junkers Jumo engines.