Spitfire Mk III

[Greenshirt]

An another thread the idea of using the Italeri Mk IX as the basis for the Spitfire III came up. Instead of highjacking that thread, I decided to start a new one.

First, I admit I have limited references. The web did not add anything to what I have. Here's what information I have from my two references.

Spitfire Mk III (N3297) was only a single airframe. It was a redesign of the Spitfire during BoB time frame and superseded by the Spitfire V as the "next" design into production.

Reference 1: MDF 3, Spitfire part 1 (Merlin Powered)

Key details:

• Clipped wingspan
  
• Merlin XX, increased length from 29' 11" to 30' 4”
  
• 3-blade DH prop
  
• Armored glass inside windshield
  
• Retractable tail wheel
  
• change to undercarriage? not specific
  
• Fully enclosed undercarriage with additional outer doors
  
• Deeper radiator
  
• “Mk V” oil cooler
  

Notes:

1. Drawing on page 67 shows forward slant to firewall forward of fuel tank. Q: Does this mean a smaller fuel tank with an added (larger) oil tank moved from beneath the engine?
   
2. Recommends start with Mk Ia kit.
   

Reference 2: Spitfire In Action, No 39

Same as MDF, but describes landing gear with 2 inches forward rake

Markings:

• Dark Earth / Dark Green / Yellow
  
• B Scheme
  
• Yellow “P” in circle on fuselage sides aft of roundel?
  
• Night serial and spinner
  

I'm thinking a cross-kitting of the Italeri Mk IX fuselage (because it's too short for a IX, but too long for the V) would be the right start. Mated to a new tool Airfix Mk IIa wing or trim, sand and rescribe the Italeri wing? A retractable tail wheel from a Hasegawa Mk VII/VIII kit and a radiator from where? Would a modified Mk I radiator work, or should something deeper from another kit be better? Reference 1 recommends the Frog XIVe radiator. I don't have that kit, but is the retractable tail wheel an option?

Tim

[gingerbob]

Spitfire Mk III (N3297) was only a single airframe. It was a redesign of the Spitfire during BoB time frame...

Already wrong. There was a second (W3237, I think). And N3297 was initiated in late '38, was on again off again, and first flew in March '40, well before BofB. The 2" forward rake was on the second, NOT the first.

There's a thread from a few months (?) back about the Mk.III- worth digging up. I don't have time to add more at the mo'.

bob

Edited May 4, 2011 by gingerbob

[bentwaters81tfw]

Go here.

http://www.britmodeller.com/forums/index.php?showtopic=58779

[Greenshirt]

My apologies if I've restarted something and am rehashing an older thread. I tried a search and came up with over a 1000 threads so obviously my ability to search is not yet refined. Thanks for the quick link.

Tim

[Giorgio N]

There's a chapter on this mark in Spitfire the History, that includes pictures of the two prototypes.

Regarding how to better reproduce the features seen in the picture, I can add:

Propeller: the first prototype was fitted with different propellers through its life. A DH ws initially used and a Rotol followed

Wingtips: these were initially of the shorter wing span, then standard ones were used.

Radiator: definitely deeper than the Mk.I. I believe it can be made starting from a Mk.I radiator, but it's down to how hapy you are with this kind of jobs.

Wing: wing the italeri wing will need closing the hole left by one radiator. Can be done of course. Using an airfix wing might give some problem at the wing fuselage junction but is probably better.

Tailwheel: I wouldn't bother looking for a hasegawa part if you don't already have it, it's possible to carve away the area in the italeri fuselage and lengthen the tailwheel leg. A couple of scratchbuilt doors will finish the job. Altetrnatively, use the part from the Frog kit if you're chasing one for the radiator (eastern repops of the frog kit can be found very cheap).

Cowling: the italeri spit will require some work to achieve the bulged shape over the exhausts. I believe that starting from an Airfix Mk.I and lengthening the fuselage might be a better option...

Exhausts: these seem to me to be different from any other spitfire exhaust I've seen...

Wheels: 5 spoke wheels.

This just from looking at pics, I'm sure someone better knowledgeable than me will provide more information.

[Greenshirt]

There's a chapter on this mark in Spitfire the History, that includes pictures of the two prototypes.

Regarding how to better reproduce the features seen in the picture, I can add:

Propeller: the first prototype was fitted with different propellers through its life. A DH ws initially used and a Rotol followed

Wingtips: these were initially of the shorter wing span, then standard ones were used.

Radiator: definitely deeper than the Mk.I. I believe it can be made starting from a Mk.I radiator, but it's down to how hapy you are with this kind of jobs.

Wing: wing the italeri wing will need closing the hole left by one radiator. Can be done of course. Using an airfix wing might give some problem at the wing fuselage junction but is probably better.

Tailwheel: I wouldn't bother looking for a hasegawa part if you don't already have it, it's possible to carve away the area in the italeri fuselage and lengthen the tailwheel leg. A couple of scratchbuilt doors will finish the job. Altetrnatively, use the part from the Frog kit if you're chasing one for the radiator (eastern repops of the frog kit can be found very cheap).

Cowling: the italeri spit will require some work to achieve the bulged shape over the exhausts. I believe that starting from an Airfix Mk.I and lengthening the fuselage might be a better option...

Exhausts: these seem to me to be different from any other spitfire exhaust I've seen...

Wheels: 5 spoke wheels.

This just from looking at pics, I'm sure someone better knowledgeable than me will provide more information.

Thanks, Giorgio.

From reading the other thread, I had no idea the canopy/windshield was unique. There's a picture reproduced there that leads me to believe the cowling was more bulged than even the Airfix Mk I would portray; but much less than a Griffon cowling. Maybe using a Griffon cowling and trim it down would give the right look?

I have little information, due to lack of references, on what changed and when. What would the configuration be, say, during the Fall of 1940?

Wingtips: interesting that the MDF leads the reader to believe the short span was basically the same short span of later marks. I've not read anything about the wing being redesigned, so would this mean just a shorter wing, crop the ailerons and square the tips? Or, is it a different shape? The photo almost gives that impression.

Tailwheel: I had to do that on Griffon kit (Fujimi I believe) so doing it again is easy.

Exhausts: Why not the same as the Merlin XX on the Hurricane? They appear similar to an early Hurricane exhaust.

Radiator: how much deeper or would something about the size of a late Griffon mark work? (Not a Mk XII radiator.)

Regards,

Tim

[John Aero]

Thanks, Giorgio.

From reading the other thread, I had no idea the canopy/windshield was unique. There's a picture reproduced there that leads me to believe the cowling was more bulged than even the Airfix Mk I would portray; but much less than a Griffon cowling. Maybe using a Griffon cowling and trim it down would give the right look?

I have little information, due to lack of references, on what changed and when. What would the configuration be, say, during the Fall of 1940?

Wingtips: interesting that the MDF leads the reader to believe the short span was basically the same short span of later marks. I've not read anything about the wing being redesigned, so would this mean just a shorter wing, crop the ailerons and square the tips? Or, is it a different shape? The photo almost gives that impression.

Tailwheel: I had to do that on Griffon kit (Fujimi I believe) so doing it again is easy.

Exhausts: Why not the same as the Merlin XX on the Hurricane? They appear similar to an early Hurricane exhaust.

Radiator: how much deeper or would something about the size of a late Griffon mark work? (Not a Mk XII radiator.)

Regards,

Tim

The wing shape would not have changed except for the reduction in span to 30' (3' 5" each side) not 30'6" as given in the MDF, and shorter than a later "clipped" spit wing. The cowling isn't IMO more bulged but is very similar to an early Mk.9. It may have a slightly fuller curve at the begining of the cylinder banks, if anything. A Griffon cowl with it's lower thrustline is totally different. It's odd appearance is due to the black painted panels around the exhausts. The main radiator is very similar in appearance to that on the Mk.18. Think Mk.9 with a three blade Rotol prop and single deep radiator. As far as the canopy goes it flew with a pretty standard canopy and some canopy mods were tested in a wind tunnel some of which are reminicent of the pre-war high speed Spitfire.

I don't think that there's any great mystery with this aeroplane.

John

[Doug Rogers]

I think there was a subtle difference in the wing leading edge where it meets the fuselage too, wasn't there, think it was lower down than standard? Not sure if it would be apparent in 1/72 scale

[Giorgio N]

I agree with John on the bulge, no need to use a griffon spit cowling. The main problem is that the Italeri IX cowling has no bulge at all. When I used one to build a Seafire I had to add plasticard to the cowling sides over the exhaust and this would have not been required using a standard Mk.V cowling. The pictures on StH seem to show a bulge similar to a Mk.V, with the main differences being at the front. Nothing major if starting from a Mk.I or V, some plasticard to add if using the Italeri parts.

You may be right about the exhausts being similar to the hurricane's, however I know little about the latter details. If you use Hurri exhausts from another kit, you'll meet another problem of the italeri kit: the exhaust area is too short, as if Italeri squeezed 6 exhaust tubes in the length needed for 5. Better lengthen the slot accordingly, this will make room for the exhausts you'll decide to use. The original italeri Mk.IX exhausts would not be ok anyway as they represent the 6 stack type.

Other small detail to keep in mind: use the Mk.I horizontal tailplanes, not the Mk.IX ones.

Doug, the different leading edge was tested on later marks, not on the Mk.III

[gingerbob]

The wing shape would not have changed except for the reduction in span to 30' (3' 5" each side) not 30'6" as given in the MDF...

I don't think that there's any great mystery with this aeroplane.

John

The mystery is in how incorrect nearly all descriptions of it (them) are! Sorry John, but you're wrong on the span- I have various sources quoting near enough 30'6" (though there too, and I'm talking about Supermarine sources, the math doesn't *quite* agree, but collectively it is pretty clear). Essentially you cut off the wing at the outboard aileron hinge (outer edge, obviously) and then stick a blunt wingtip on. (Ahh, but is that length-of-wing-panel span, or "sitting in the hangar wingtip-to-wingtip span"?)

The original windscreen was the unique one, quickly replaced with the type that later went into production on the Mk.V and beyond. At about the same time the Rotol, again as seen on later Mk.Vs, was fitted. It was also fully flush-riveted, as were the first 20 or so Mk.Is (!- not certain of the figure).

The cowl is 4" longer than a Mk.I/V cowl, whereas the Merlin 61 cowl is 9" longer than Mk.I/V, in case anyone is still confused.

The radiator may be shaped roughly like a Griffon one, but is different- it has a boundary-layer splitter, first experimented with on the Speed Spit. Interestingly, when the clipped wing was replaced with a full-span wing, the clipped wing was "repaired" to become an extended-tip wing on the first pressure prototype (essentially the Mk.VI prototype). The custom radiator remained, as did a shorter aileron (as went into production on the Mk.VII/VIII).

I'm not aware of the wing root being different. First prototype was always 'a' type armament (whether or not guns fitted), the second was the first Universal wing, and as I said before introduced the 2" forward rake of the gear. This was NOT on the first prototype.

bob

p.s. Thanks to someone for digging up the link to the other thread!

[Giorgio N]

Essentially you cut off the wing at the outboard aileron hinge (outer edge, obviously) and then stick a blunt wingtip on. (Ahh, but is that length-of-wing-panel span, or "sitting in the hangar wingtip-to-wingtip span"?)

Bob, is the supermarine drawing of the wing present on the History correct ? Looks like it fits your description

Edited May 5, 2011 by Giorgio N

[John Aero]

The mystery is in how incorrect nearly all descriptions of it (them) are! Sorry John, but you're wrong on the span- I have various sources quoting near enough 30'6" (though there too, and I'm talking about Supermarine sources, the math doesn't *quite* agree, but collectively it is pretty clear). Essentially you cut off the wing at the outboard aileron hinge (outer edge, obviously) and then stick a blunt wingtip on. (Ahh, but is that length-of-wing-panel span, or "sitting in the hangar wingtip-to-wingtip span"?)

The original windscreen was the unique one, quickly replaced with the type that later went into production on the Mk.V and beyond. At about the same time the Rotol, again as seen on later Mk.Vs, was fitted. It was also fully flush-riveted, as were the first 20 or so Mk.Is (!- not certain of the figure).

The cowl is 4" longer than a Mk.I/V cowl, whereas the Merlin 61 cowl is 9" longer than Mk.I/V, in case anyone is still confused.

The radiator may be shaped roughly like a Griffon one, but is different- it has a boundary-layer splitter, first experimented with on the Speed Spit. Interestingly, when the clipped wing was replaced with a full-span wing, the clipped wing was "repaired" to become an extended-tip wing on the first pressure prototype (essentially the Mk.VI prototype). The custom radiator remained, as did a shorter aileron (as went into production on the Mk.VII/VIII).

I'm not aware of the wing root being different. First prototype was always 'a' type armament (whether or not guns fitted), the second was the first Universal wing, and as I said before introduced the 2" forward rake of the gear. This was NOT on the first prototype.

bob

p.s. Thanks to someone for digging up the link to the other thread!

The obvious place to make a change to the wing would be rib 19 which is the outer aileron hinge, and which now looking at the drawing on page 130 of the S&M book is what Supermarine did. A tip of approx some 6" depth was added. To do this the wing is reduced by almost exactly 48" to rib 19. Add a tip of approx 6" to the truncated wing will give a new reduced wing (panel) difference of 3' 5" as quoted in some publications. My maths are, Standard wing 36' 10.5", reduced by 2x 3' 5" is 30'. Yes I agree that the construction of the rad is totally different (in reallity) but from a model point of view a Griffon rad is a good place to start. A wide sawcut down the nose of a Mk.9 (in the right place) would soon sort out the length difference. IMO Supermarines are a nightmare chonologically as bits and pieces of "inhouse research" turn up in later types as production items. I give for instance the MkVIII JF299 which at some point sported what is an obvious Mk 17 windscreen and canopy.

John

[gingerbob]

IMO Supermarines are a nightmare chonologically as bits and pieces of "inhouse research" turn up in later types as production items. I give for instance the MkVIII JF299 which at some point sported what is an obvious Mk 17 windscreen and canopy.

John

It seems I must go check the data and my math! Meanwhile we seem to agree on the concept, just not the number. Meanwhile, veering off track:

Bits and pieces, indeed, and sorting the chronology (and the oft misunderstood "why/how?"), as you know, is what attracts me to the Spitfire line. And the stunning good looks, and the romantic "There'll be bluebirds over..." and the comaraderie (sp?) of other addled people like me, and the wide open possibilities for model subjects and conversions, and...

As to JF299, that was the first TI (trial installation) of the "all-round-view" hood, proposed by Supermarine to address the poor rear view and, at the same time, to increase the sighting view by allowing pilot and gunsight to sit a bit higher. The curved windscreen was expected to reduce drag at high speeds, as well. Similar windscreens (still with high-back) were tested on DP845, DP851, PP139, NN660 (actually parts taken from PP139, which received the standard windscreen/hood) and also on a Mk.V. Perhaps others, too.

Alas, the RAF had some complaints about the curved windscreen and firmly rejected it, forcing Supermarine to design a "rear-view" hood to meet the standard "Mk.III" windscreen (see, it IS on topic!), which eliminated the opportunity to raise the gunsight, which led Joe Smith to design a new, humped fuselage for what would eventually be called the Spiteful.

Meanwhile, the FAA (Admiralty) wanted the curved windscreen. I don't know why- speculating: They liked the increased view over the nose for landing-on? They wanted the high-speed drag reduction? They wanted to assert their independence from the RAF? For that reason, the Seafires that were "fully evolved" (Sea 17, Sea 47, Seafang) had the curved-front windscreen and hood to match, while the "conversions" (Sea 45, 46) had the RAF type windscreen and hood. I don't know about the alleged low-back Sea 15s- I would assume that they were same as Sea 17, but I need to get more hard info.

bob

[John Aero]

It seems I must go check the data and my math! Meanwhile we seem to agree on the concept, just not the number. Meanwhile, veering off track:

Bits and pieces, indeed, and sorting the chronology (and the oft misunderstood "why/how?"), as you know, is what attracts me to the Spitfire line. And the stunning good looks, and the romantic "There'll be bluebirds over..." and the comaraderie (sp?) of other addled people like me, and the wide open possibilities for model subjects and conversions, and...

As to JF299, that was the first TI (trial installation) of the "all-round-view" hood, proposed by Supermarine to address the poor rear view and, at the same time, to increase the sighting view by allowing pilot and gunsight to sit a bit higher. The curved windscreen was expected to reduce drag at high speeds, as well. Similar windscreens (still with high-back) were tested on DP845, DP851, PP139, NN660 (actually parts taken from PP139, which received the standard windscreen/hood) and also on a Mk.V. Perhaps others, too.

Alas, the RAF had some complaints about the curved windscreen and firmly rejected it, forcing Supermarine to design a "rear-view" hood to meet the standard "Mk.III" windscreen (see, it IS on topic!), which eliminated the opportunity to raise the gunsight, which led Joe Smith to design a new, humped fuselage for what would eventually be called the Spiteful.

Meanwhile, the FAA (Admiralty) wanted the curved windscreen. I don't know why- speculating: They liked the increased view over the nose for landing-on? They wanted the high-speed drag reduction? They wanted to assert their independence from the RAF? For that reason, the Seafires that were "fully evolved" (Sea 17, Sea 47, Seafang) had the curved-front windscreen and hood to match, while the "conversions" (Sea 45, 46) had the RAF type windscreen and hood. I don't know about the alleged low-back Sea 15s- I would assume that they were same as Sea 17, but I need to get more hard info.

bob

Bob

Thank you for the added info. However my point of this was the extra rake angle of the hood /windsreen contact frame, seen only on one Seafire..... the Mk.17. I believe the Navy's interest in the curved screen was that it shed water better.

John

[Greenshirt]

The mystery is in how incorrect nearly all descriptions of it (them) are! Sorry John, but you're wrong on the span- I have various sources quoting near enough 30'6" (though there too, and I'm talking about Supermarine sources, the math doesn't *quite* agree, but collectively it is pretty clear). Essentially you cut off the wing at the outboard aileron hinge (outer edge, obviously) and then stick a blunt wingtip on. (Ahh, but is that length-of-wing-panel span, or "sitting in the hangar wingtip-to-wingtip span"?)

The original windscreen was the unique one, quickly replaced with the type that later went into production on the Mk.V and beyond. At about the same time the Rotol, again as seen on later Mk.Vs, was fitted. It was also fully flush-riveted, as were the first 20 or so Mk.Is (!- not certain of the figure).

The cowl is 4" longer than a Mk.I/V cowl, whereas the Merlin 61 cowl is 9" longer than Mk.I/V, in case anyone is still confused.

The radiator may be shaped roughly like a Griffon one, but is different- it has a boundary-layer splitter, first experimented with on the Speed Spit. Interestingly, when the clipped wing was replaced with a full-span wing, the clipped wing was "repaired" to become an extended-tip wing on the first pressure prototype (essentially the Mk.VI prototype). The custom radiator remained, as did a shorter aileron (as went into production on the Mk.VII/VIII).

I'm not aware of the wing root being different. First prototype was always 'a' type armament (whether or not guns fitted), the second was the first Universal wing, and as I said before introduced the 2" forward rake of the gear. This was NOT on the first prototype.

bob

p.s. Thanks to someone for digging up the link to the other thread!

Thank you Bob & John; very enlightening.

Bob, your notes above indicate (or confuse me) regarding the ailerons. Were they also shortened when the wing was shortened? If shortened, would I use the Mk VII/VIII length?

I'm closing in on N3297 as the subject I'd like to tackle as it appears to be less different than the second Mk III. Given how poorly the Italeri Mk IX cowl is, and the amount of change I'd need to make, I may attack this with a Mk Ia by adding 4" to the cowl. I'll need to fiddle a bit with each kit...

Tim

[gingerbob]

Sorry about the confusing aileron reference. With the initial wing they were short because the wing (and aileron) was cut down to the outer hinge point. Even when the span was restored and the wing used on the pressure prototype, it still had a shorter than standard aileron, which was inherited by the Mk.VII/VIII. Clearly this was still a part of design development, though I've not been able to discover whether the shortened (Mk.VII/VIII) aileron actually made any difference. Perhaps it raised theoretical flutter speed or something, but it seems to me that if it was significant they could have switched the Vc/IX side over to it without much heartburn. Incidentally, I don't think the full-span wing was fitted to N3297 until early '41, and I believe that it, too, had a shortened aileron- though I'm going on memory, so not to be trusted without confirmation. [Edit: Oops, wrong! There's a good shot in the other thread that clearly shows a full-span aileron on N3297 when she's fitted with the 2-stage Merlin.]

John, I confess you've got me outmanouevred (however you chaps spell that silly word!) with the Sea 17 windscreen. But if it is the same as that on the Mk.VIII TI, then the real question is, why did they have to alter it again on the Sea 47? Obviously I haven't found out as much about the Seafires yet.

bob

Edited May 7, 2011 by gingerbob

[Greenshirt]

Thanks, Bob. Definitely short ailerons on a short(er) span wing.

Regards,

Tim

[John Aero]

Sorry about the confusing aileron reference. With the initial wing they were short because the wing (and aileron) was cut down to the outer hinge point. Even when the span was restored and the wing used on the pressure prototype, it still had a shorter than standard aileron, which was inherited by the Mk.VII/VIII. Clearly this was still a part of design development, though I've not been able to discover whether the shortened (Mk.VII/VIII) aileron actually made any difference. Perhaps it raised theoretical flutter speed or something, but it seems to me that if it was significant they could have switched the Vc/IX side over to it without much heartburn. Incidentally, I don't think the full-span wing was fitted to N3297 until early '41, and I believe that it, too, had a shortened aileron- though I'm going on memory, so not to be trusted without confirmation.

John, I confess you've got me outmanouevred (however you chaps spell that silly word!) with the Sea 17 windscreen. But if it is the same as that on the Mk.VIII TI, then the real question is, why did they have to alter it again on the Sea 47? Obviously I haven't found out as much about the Seafires yet.

bob

Bob

I suspect the short answer is cost, As the RAF weren't keen on, or considered no real advantage for changing the Spitfire screens and frame, the 47 used a standard hood and screen support frame but held on to the curved outer screen. The Seafire 17 canopy/frame is unique as a production item and is a rare example of the bean counters being asleep.

John

Edited May 5, 2011 by John Aero

[Edgar]

I've stayed out of this, since my only other reference (distinct from that of everybody else,) is a booklet about a 40th anniversary series of lectures, and figures suppled by Joe Smith give the Mk.III dimensions as 30'6" and 36'10" with a wing area of 220 & 242 sq.ft., respectively (the wing areas for the clipped XII, XIV & XVIII are given as 231 sq.ft.) Anyway, I thought that these illustrations might be useful.

At first sight, the 47 seems to be the 46 with an add-on, but careful scrutiny shows this not to be the case.

As far as I can see, the RAF Museum only have two G.A. drawings, for the III, which could quite conceivably be those in StH.

Edgar

Edited May 6, 2011 by Edgar

[gingerbob]

As far as I can see, the RAF Museum only have two G.A. drawings, for the III, which could quite conceivably be those in StH.

Yes, as I recall, one of the drawings at the RAF Museum is the one shown in Spit the Hist. And the other I don't think was terribly useful. There are also some drawings (more general than engineering drawings, but good) in the Type Record, also at the Museum. Georgio, yes, the wing drawing (if it's the one I'm thinking of) in STH is accurate (I think it came from the Type Record), though when I tried to enlarge it to work with my 48th Tamiya kit it wasn't a SCALE drawing.

Thanks for corroborating my quoted figure, Edgar, though there may remain the question of the sums. I think I was able to make them come out right when I checked the various statements and evidence, though I had to throw out some that didn't agree with what appeared to be correct. When it comes to "archival" work I'll be at a disadvantage for a few weeks, as today I take up crowbar and begin to get violent with portions of my house!

Thanks also for the windscreen illustrations. Is it not true that the design changed during Seafire 47 production?

bob

[Edgar]

Thanks also for the windscreen illustrations. Is it not true that the design changed during Seafire 47 production?

Seafire Mod 881 "To introduce new windscreen & sliding hood" (my italics) was introduced, as leaflets only, not into production (though there's an enigmatic reference to "Reed," plus some unreadable dates,) in May, 1947; the illustrations come from various A.P.s. Incidentally, every A.P. shows the wingspan as being a direct point-to-point measurement, never down the dihedral, and back up again.

Sorry for pushing this way away from the Spitfire III.

Edgar

Edited May 6, 2011 by Edgar

[rpaddy]

Hello Guys,

I find another interesting picture about :

http://www.aeroflight.co.uk/wp-content/upl...3/spit3-vic.jpg

Roberto

[gingerbob]

Drawing on page 67 shows forward slant to firewall forward of fuel tank. Q: Does this mean a smaller fuel tank with an added (larger) oil tank moved from beneath the engine?

Tim

Hi Tim,

We haven't really talked about the angled firewall (have we?)- I shouldn't say this without checking first, but I think on the III it allowed a larger fuel tank while the oil tank stayed where it had been. This (firewall) appeared again on Mk.VII prototypes and perhaps a very few early production ones, but did NOT become standard on the VII/VIII. It showed up again on the XIV and subsequent Griffon types. If I remember right it was also on DP845, the single-stage Griffon prototype, but NOT on the Mk.XII/Sea 15/17.

Incidentally, on N3297 (remember that?!) she was initially painted with the white/black wing undersides (alu. chin and under-fuselage). The yellow undersides for prototypes came a few months later, and she was repainted accordingly.

Edgar, you're still on topic (or you pulled it out of a hat!)- and after all, I was one of the guilty parties who explored a side-street. I agree with what you say about wingspan, but on the manufacturing drawings for the wing they would have been measuring in the plane of the wing (no pun intended), as would we if checking locations. That's why I brought it up.

bob

p.s. An alert: I've just corrected an earlier statement- when fitted with a full-span wing N3297 had a normal aileron, not a shortened one. I think they used an "off the shelf" Mk.I wing, suitably modified, and then soon modified more with the 2-stage Merlin needs.

Edited May 7, 2011 by gingerbob

[Greenshirt]

Hi Tim,

We haven't really talked about the angled firewall (have we?)- I shouldn't say this without checking first, but I think on the III it allowed a larger fuel tank while the oil tank stayed where it had been. This (firewall) appeared again on Mk.VII prototypes and perhaps a very few early production ones, but did NOT become standard on the VII/VIII. It showed up again on the XIV and subsequent Griffon types. If I remember right it was also on DP845, the single-stage Griffon prototype, but NOT on the Mk.XII/Sea 15/17.

Incidentally, on N3297 (remember that?!) she was initially painted with the white/black wing undersides (alu. chin and under-fuselage). The yellow undersides for prototypes came a few months later, and she was repainted accordingly.

Edgar, you're still on topic (or you pulled it out of a hat!)- and after all, I was one of the guilty parties who explored a side-street. I agree with what you say about wingspan, but on the manufacturing drawings for the wing they would have been measuring in the plane of the wing (no pun intended), as would we if checking locations. That's why I brought it up.

bob

p.s. An alert: I've just corrected an earlier statement- when fitted with a full-span wing N3297 had a normal aileron, not a shortened one. I think they used an "off the shelf" Mk.I wing, suitably modified, and then soon modified more with the 2-stage Merlin needs.

Thanks for the corrections. I want the Mk III because of its uniqueness in the Mk I/II to V timeline. So I want the clipped wings which means short span ailerons. In the other thread the photos show clearly the b/w undersides to the wings, but no prototype markings ("P" in circle). When did this marking get applied (if at all). Related, was the repaint of the undersides to yellow coincident with replacement of the wing to full span?

Thanks,

Tim

[gingerbob]

I think the circle-P came at the same time (or close) as the yellow underside- summer '40. I thought someone would have piped up with the details by now! So still clipped wing. By the way there was a fair amount of experimenting with the ailerons (moving hinge point back and forth, more ribs, maybe metal covered eventually) but that's getting down to brass-tacks. If you home in on a specific set of characteristics you want I can probably help fill in the details, but don't expect instant results! ...and now back to removing plaster and lath.

bob

p.s. As you may have deduced, the Mk.IIIs (and other prototypes) are among my pet subjects.