# Spitfire's drag - what was good, and what was not?



## tomo pauk (Oct 10, 2012)

Reading recently about the Fw-190As, one thing from the manual for the A-5/A-6 popped out as interesting: the A-5/A-6 were as fast, on about the same HP, on same altitude, as Spitfire MkV (Fw using the Max continous rating, 1180 PS) or Spitfire Mk.VIII/IX (Fw using the Emergency rating, 1440 PS). I wonder why the Spitfire was not faster, being powered by the V-12 (= inherently less drag)? Was it because of it's bigger wings, or the fixed tail wheel messed things in Mk. V/IX case (but still the Mk.VIII cannot come ahead, despite the retractable tail wheel), was it because the radiator(s) were draggy, or all parts played about the equal part? IIRC the Spitfire having thinner wing (someone with knowledge can chip in here, too), to offset the total wing drag? The Fw-190A-5 was also far heavier, especially vs. the Mk.V.
The chart can be found at Williams' site, the red dot represent's Mk.V's best value. The pink dot represents Mk.VIII/IX, 404 mph at 21000 ft (Merlin 66 aboard); the hi-alt versions of Merlin were able to propel the Spit at thinner air (less drag = more speed), but obviously they cannot be compared here. Maybe with the D-9.
The 'slower' lines of the Fw's speed are the one of interest (= with compressibility taken into account).


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## Juha (Oct 10, 2012)

Hello Tomo
Spitfire's important drag-generators when compared other contemporary fighters, draggy radiator(s) and less inclined windscreen with sharp corners.

juha

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## RCAFson (Oct 11, 2012)

The FTH of a Merlin 45 was about 13000ft, at 16lb boost, and at that Altitude the Spit V made about 370 mph. I think you need to compare engine output vs altitude and also use Allied estimates of the 801 engines output, since there may be differences between the Luftwaffe and RAF in determining engine output.


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## drgondog (Oct 11, 2012)

I agree Juha but would add that the additional wing area was a parsite drag contributor in contrast to 109 and 190. The CD0 of the Spit was slightly lower than the FW 190, for example, but the wetted area was larger and the resultant flat plate drag comparisons favor the FW 190 by ~ 3%.


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## tomo pauk (Oct 11, 2012)

Juha said:


> Hello Tomo
> Spitfire's important drag-generators when compared other contemporary fighters, draggy radiator(s) and less inclined windscreen with sharp corners.
> 
> juha



Thanks.



RCAFson said:


> The FTH of a Merlin 45 was about 13000ft, at 16lb boost, and at that Altitude the Spit V made about 370 mph. I think you need to compare engine output vs altitude and also use Allied estimates of the 801 engines output, since there may be differences between the Luftwaffe and RAF in determining engine output.



I was comparing engine output with altitude, but don't mind to elaborate further on the matter.
The Merlin 45 running at 16 lb boost @ 13000 ft (1500+ HP) will be running at 9 lb boost @ cca 20000 ft, producing 1150-1200 HP there (all with ram effect). The Fw's 1180 PS means ~1164 HP (one HP is worth 1.014 PS), and are achieved at 19680 ft, with ram.
At those 13000 ft (~4030m), Spit's 1500 HP (370 mph) are to be compared with under 1400 HP of the Fw, and the Fw still comes ahead (almost 610 km/h, or almost 380 mp/h).

The data for the Spitfire VIII (from Williams' site):

```
Spitfire LF VIII	Merlin 66	
1,720 @ 5,750'   384 mph @ 10,500' MS
1,595 @ 16,000' 404 mph @ 21,000' FS
```
The value of 1595 HP at 16000 ft is for the static engine, ie. no ram. The altitude of the max speed at FS gear (21000 ft) points us at the altitude value with ram. So we compare 1595 HP and 404 mp/h for the Mk.VIII; the Fw-190A-6 making 410 mph with 1420 HP (=1440 PS) at ~20320 ft. 



drgondog said:


> I agree Juha but would add that the additional wing area was a parsite drag contributor in contrast to 109 and 190. The CD0 of the Spit was slightly lower than the FW 190, for example, but the wetted area was larger and the resultant flat plate drag comparisons favor the FW 190 by ~ 3%.



Thanks - size indeed does matter.


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## riacrato (Oct 11, 2012)

I am not so sure on the radiator, they seem to have a large (exposed) frontal area but iirc the German evaluation of the SpitV with DB concluded that the installation was rather efficient and with better _Durchflusswiderstand_ than the contemporary Bf 109 radiator. Which aircraft had a better (less drag) radiator setup at the time (Mustang, Fw 190 D were certainly better srill some months/years in the future.


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## RCAFson (Oct 11, 2012)

tomo pauk said:


> Thanks.
> 
> 
> 
> ...



The USAAF came up with these figures which differ widely from yours:





The same report gives the maximum output as 1750BHP:
_



II Summary

The German Focke-Wulf 190, EB-104 is a single place, low wing all metal monoplane, powered with a 1750 bhp BMW 801-D fourteen cylinder two row radial engine equipped with a two speed internal supercharger.

Click to expand...

_Fw 190 G-3 Performance Test


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## tomo pauk (Oct 11, 2012)

The better (lower) _Durchflusswiderstand_ (resistance to the flow) was pointing to the resistance to the coolant flow, not to the resistance to the air stream. 
Looking at the photos of the Spitfire's wing under side, the radiator lacks boundary splitter (like P-51 had), or tunnel (like Bf-109F and later; Spiteful/Seafand seem to have the same layout, with the tunnel?). Further, the radiator is short, but tall, with wide opening at the front.


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## tomo pauk (Oct 11, 2012)

RCAFson said:


> The FTH of a Merlin 45 was about 13000ft, at 16lb boost, and at that Altitude the Spit V made about 370 mph. *I think you need to compare engine output vs altitude* and also use Allied estimates of the 801 engines output, since there may be differences between the Luftwaffe and RAF in determining engine output.


 


RCAFson said:


> The USAAF came up with these figures which differ widely from yours:
> View attachment 213143
> 
> 
> ...



I thought we were comparing engine output vs. altitude 
German data (from Fw-190A-5/A-6 manual) gives the max output of 1730 PS (1706 BHP), so it should be within factory tolerances vs. the 1750 BHP output from the report. But that is at ~1500 (4830 ft) of altitude (with ram; 600 m without ram), and there the 190A-6 does 600+ km/h (370+ mph). US chart gives 374 mph at 6000 ft, achieved with 1750 BHP. 
For comparison, the Spitfire XII does 375 mph at 4,600 ft; another test gives 372 mph at 5,700 ft. Speeds achieved with 1720 BHP.

Sure enough, a (non turbo) engine doing maximum of 1700-1750 BHP at low altitude is never going to make that power at 20000 ft:


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## riacrato (Oct 12, 2012)

tomo pauk said:


> The better (lower) _Durchflusswiderstand_ (resistance to the flow) was pointing to the resistance to the coolant flow, not to the resistance to the air stream.
> Looking at the photos of the Spitfire's wing under side, the radiator lacks boundary splitter (like P-51 had), or tunnel (like Bf-109F and later; Spiteful/Seafand seem to have the same layout, with the tunnel?). Further, the radiator is short, but tall, with wide opening at the front.


 
yes and it meant the spitfire radiator could effectively cool the db engine while having only about 50-60 per cent the size / frontal area of a 109 f or g radiator. of course things change once the intercooler is added.


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## tomo pauk (Oct 15, 2012)

I wonder how much is the better cooling capacity to be attributed to the use of copper, instead of aluminum?

Here is what our drgondog (Bill Marshall) said in another thread, why P-51 was so fast:



> Schmeud and Atwood stated 1st (Laminar Flow wing), 2nd (redesigned 51B/D radiator form and boundary layer control over inlet duct, 3rd (Meridith effect).
> 
> There is one other possible contribution, namely the windscreen/canopy design. Lednicer presented interesting potential flow model that showed the 51D design to be superior to Mk IX and FW190D canopy and slightly better than a P-51B.
> 
> The 51D design seemed to avoid flow stagnation at base of windscreen and therfore improved attached flow properties over top and rear surfaces of the canopy.



As known from the dive tests and limitations noted in manual, the dive speeds were rather high (higher than of P-47, for example). That should point us to the wings as being of relatively low drag coefficient (still the drag force was ~3% greater than Fw, because the wetted area was some 25% higher). 
Spitfire was found lacking two things: boundary layer separator (or tunel, playing the same role?) for the radiator(s), while the inner shape of the radiator was ill suited to fully harvest the Meredith effect. Maybe the (under) wing placement was restricting the convenient radiator height, in order to sufficiently slow the air flow after it enters the radiator casing? Also, the radiator casing was restricted in possible length, since it was located between U/C leg space (when retracted) and flap - not allowing to the Meredith effect to happen at a desirable level. 

The excerpts from this thread (here)do mention some other things: contrary to the radiator's exit flap of the P-51, that was progressively adjustable, the exit flap from the Spit (IX is mentioned in the article) have had two positions: fully open and partially closed, again messing with the M. effect. P-51s (Packard Merlin versions?), with propeller giving 1000 lbs while engine in full power, radiator's drag was 400 lbs, being couteracted with 350 lbs of thrust from the Meredith effect. So the cooling drag went down by an order of magnitude.

Finally, about the fixed tailwheel: Germans discovered that such a thing costs 12 km/h in their Bf-109Gs, or 7,45 mp/h.


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## tomo pauk (Nov 15, 2012)

The Spitfire shared one feature with it's arch rival, the Bf-109, namely the wheels that were not fully closed up when retracted (maybe some 50% of the wheel was covered, for both planes). Germans concluded that wheel well covers can add cca 11-14 km/h for their Bf-109Gs (from Kurfurst's site).
Spitfire introduced the wheel well covers with Mk.21. From spitfiresite.com:



> The undercarriage could be also fully enclosed in flight due to the new outer undercarriage covers.


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## Tante Ju (Nov 15, 2012)

riacrato said:


> yes and it meant the spitfire radiator could effectively cool the db engine while having only about 50-60 per cent the size / frontal area of a 109 f or g radiator. of course things change once the intercooler is added.



It's a a bit tricky to compare radiator sizes by their numbers.. The Spitfire V used one rather large and heavy radiator of copper, the 109 used two smaller and lighter (though in total weighting about the same) coolant radiators.


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## riacrato (Nov 15, 2012)

True, but the question was on drag. And the Spitfire seems to definetly have a smaller frontal area. So all else (total weight, cooling performance...) being equal, they seem to be better overall.


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## tomo pauk (Nov 16, 2012)

Curiously enough, the early Fw-190s were featuring the wheel well covers, while the later ones did not. Instead, the covers attached at the wheel struts were of increased area, now covering maybe 75-80% of the area. With the every sub-version got both heavier draggier, no wonder the Fw-190A steadily got slower, from A-3 to A-8.

added: the wheel covers were removed due the installation of bomb/fuel fuselage rack, the presence of the rack making the covers operation impossible. Information via Dieter Hermann. 
The wheel covers for the Bf-109 were installed in the K-4, but it was experimented much earlier.


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## drgondog (Nov 16, 2012)

riacrato said:


> True, but the question was on drag. And the Spitfire seems to definetly have a smaller frontal area. So all else (total weight, cooling performance...) being equal, they seem to be better overall.



For the classic long lived fighters, all (except US) had a relatively small frontal area. The wing first, then wetted area second - are the prime contributors to Drag.


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## tomo pauk (Nov 23, 2012)

Guess riacrato was thinkering of radiator's smaller area, rather than of whole plane.

Further on Spitfire: the Mk.III is stated as being equipped with 'wheel well flap', presumable a wheel well cover? However, the 'flap' is not easy to spot on the photos. Wonder if someone has some details about it?


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## Edgar Brooks (Nov 23, 2012)

Sorry, finger trouble


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## Edgar Brooks (Nov 23, 2012)

They're visible in some photos, both with blunt-tipped and elliptical wings; it only lasted as the Mk.III for less than a year, so photos are a bit rare. With the u/c down, the flaps were parallel to the ground, so only easily visible from front or rear.
The inflated dimension of the early Spitfire tyre was 24.51" (maximum,) with a hub diameter of 10"; this would give a maximum ground clearance, for the flaps, of 7.25" (18.4cm.,) possibly slightly less, which isn't much on a grass airfield, with oleos with nearly 5" of permissible travel.


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## tomo pauk (Nov 23, 2012)

Many thanks


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## Edgar Brooks (Nov 24, 2012)

tomo pauk said:


> Spitfire was found lacking two things: boundary layer separator (or tunel, playing the same role?) for the radiator(s), while the inner shape of the radiator was ill suited to fully harvest the Meredith effect. Maybe the (under) wing placement was restricting the convenient radiator height, in order to sufficiently slow the air flow after it enters the radiator casing? Also, the radiator casing was restricted in possible length, since it was located between U/C leg space (when retracted) and flap - not allowing to the Meredith effect to happen at a desirable level..


A boundary layer separator wasn't possible, since the "roof" of the radiator housing climbed up immediately after the intake lip, so that the top of the radiator matrix was just under the top skin of the wing's upper surface (this was the reason for erks being told to keep off the starboard wing.) I don't have the measurements, but the face of the radiator, in area, was roughly double that of the mouth of the housing, and the air expanded in four directions.


> contrary to the radiator's exit flap of the P-51, that was progressively adjustable, the exit flap from the Spit (IX is mentioned in the article) have had two positions: fully open and partially closed, again messing with the M. effect. P-51s


The exit flap was only opened when the climbing temperature of the coolant required it; in the IX, it was fully automatic, though the pilot could override it if he needed to.


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## riacrato (Nov 24, 2012)

tomo pauk said:


> Guess riacrato was thinkering of radiator's smaller area, rather than of whole plane.
> 
> Further on Spitfire: the Mk.III is stated as being equipped with 'wheel well flap', presumable a wheel well cover? However, the 'flap' is not easy to spot on the photos. Wonder if someone has some details about it?


 
Exactly. The radiator of the Spitfire seems to have been superior efficiency-wise to its contemporaries, achieving appr. same cooling at appr. same weight but less frontal area than for example the Bf 109. The rest of the airframe is a different matter.


Edgar Brooks said:


> A boundary layer separator wasn't possible, since the "roof" of the radiator housing climbed up immediately after the intake lip, so that the top of the radiator matrix was just under the top skin of the wing's upper surface (this was the reason for erks being told to keep off the starboard wing.) I don't have the measurements, but the face of the radiator, in area, was roughly double that of the mouth of the housing, and the air expanded in four directions.


But does that really mean no boundary layer seperation is possible? Isn't the "roof" of the P-51 radiator also higher than the intake lip? Even if not, I don't see how this fact which is also true for the 109 and probably a lot of '30s aircraft designs eliminates the possility of having a "scoop" instead of a simpler opening for the intake. I'd rather think this simply wasn't a common practice in the thirties and not seen as a worthwhile cleanup later. Maybe the redesign and the added complexity simply wasn't worth the effort. I seem to recall even for the P-51 it took some time until they figured out the best dimensions and "offset" for the boundary layer seperator.


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## drgondog (Nov 24, 2012)

riacrato said:


> Exactly. But does that really mean no boundary layer seperation is possible? Isn't the "roof" of the P-51 radiator also higher than the intake lip? Even if not, I don't see how this fact which is also true for the 109 and probably a lot of '30s aircraft designs eliminates the possility of having a "scoop" instead of a simpler opening for the intake. I'd rather think this simply wasn't a common practice in the thirties and not seen as a worthwhile cleanup later. Maybe the redesign and the added complexity simply wasn't worth the effort. I seem to recall even for the P-51 it took some time until they figured out the best dimensions and "offset" for the boundary layer seperator.



It did take time not only for the dimensions but also for the shape - and focused on the Reynolds number of the 'rumble' experienced as noise within a speed range.

Curiously the P-51H geometry and location was closer to the P-51A than B/C/D - as well as a much longer plenum aft of the radiator.

I suspect that the problem (aft wing location) with both the Spit and 109 versus the 51 is that the boundary layer buildup increases chord wise on a wing and may be subject to worsened adverse pressure gradients on the wing than centerline fuselage on the Mustang.


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## Siegfried (Nov 24, 2012)

The Fw 190 was a much heavier aircraft but also had smaller wing area: 18.5sqm as opposed to the 22.5sqm of the lighter spitfire. The Fw 190 also had NACA 5 digit airfoils as opposed to the older NACA 4 digit airfoils, these newer airfoils generated slightly better lift and also L/D ratios.

The Spitfire had a fairly messy underside which caused considerable drag, tidying up this area surely would have paid dividentds. Its so called Meredith radiator system was not particularly unique nor more effective than others despit the myths sorounding it; everyone including Messerchmitt, Curtiss and the French fighters seemed to have the technology.

Retractable tailwheels came in with the Spitifre Mk VIII but this airframe was little produced.

The Me 109F's systems was every bit as sophisticated as the excellent P-51 system; it also had a boundary layer bypass. Of course being much smaller its dimensions were far less optimal. Oddly the Me 109G gave up on the boundary layer system. I've heard it said the Spitfire's radiatorsthemselves were more effective than the Me 109in terms of frontal area but that this can be attributed to the use of copper in the Spitfire over Aluminium in the Me 109 since copper had better thermal conductivity and it might possibly be cast more fine. This was a close run thing and I don't think it was ever resolved. Copper was a critical material to the Germans. 

Modern Aluminium automotive radiators are actually hybrid plastic-aluminium systems of very fine construction.

Frontal area in a radiator is not everything, low pressure loss is perhaps more important, this is why the Germans went to anular radiators even on the Fw 190D as it allowed increased area and therefore reduced pressure loss. Napier wanted to do the same on the Sabre installations on Tempest.

The boundary layer intake seperation became an issue on split or side intake jet aircraft which the Luftwaffe wanted in order to provide for increase protection against gun fire and to allow for area ruling and as was seen on the Lockheed P-80. To do this they actually wanted to use active broundary layer control. The Messerchmitt P.1112 http://www.luft46.com/mess/mep1112.html actually was to use a 200hp compressor driven of the jet engine accesories to draw in the boundary layer. A half intake model was succesfully wind tunnel tested.

That gives an idea of its importance. 

I rather expect that the Hawker Hurricane's system would have been quite effective bar the relatively low speed.


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## tomo pauk (Nov 24, 2012)

Siegfried said:


> ...
> The Me 109F's systems was every bit as sophisticated as the excellent P-51 system; it also had a boundary layer bypass. Of course being much smaller its dimensions were far less optimal. Oddly the Me 109G gave up on the boundary layer system...



I'll just cover this tidbit. 
The 'every bit as sophisticated' cooling system of the 109F was abandoned for the 109G, since it gave no practical advantage vs. the system with no bypass. Nothing 'oddly' here, it just was not worth it. FWIW: 
http://www.luftwaffe-experten.org/forums/index.php?showtopic=16738


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## Edgar Brooks (Nov 24, 2012)

Siegfried said:


> The Spitfire had a fairly messy underside which caused considerable drag, .


You have figures, of course?


> tidying up this area surely would have paid dividentds


. 
you mean we'd have won the Battle of Britain by an even bigger margin?


> Its so called Meredith radiator system was not particularly unique nor more effective than others despit the myths sorounding it; everyone including Messerchmitt, Curtiss and the French fighters seemed to have the technology


.
Who claimed that it was unique? And, if you check, the Meredith effect is air entering an intake, then expanding, which is what happened in the Spitfire radiator(s,) so let's have a bit less of this "so-called," please.


> Retractable tailwheels came in with the Spitifre Mk VIII but this airframe was little produced.


It would be nice if you did everyone the courtesy of carrying out some research, before pontificating on a subject you obviously know little about; the Spitfire VII was the first service airframe to have a retractable tailwheel, though it was trialled first on the Mk.III. Also your "little produced" VIII ran to 1650 airframes, in just two years, more than the Mk.I (1530,) Mk.II (920,) Va (1367,) Vc (635,) VI (100,) VII (140,) XII (100,) XIV (957,) XVI (1054,) in fact only the Vb IX were built in greater numbers. Even the whole lot of Merlin-powered Seafires, I, II, III only totalled 1792.


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## Tante Ju (Nov 24, 2012)

Edgar Brooks said:


> You have figures, of course?



I agree, figures would be interesting, but even without figures it is clearcut that semi-faired undercarriage, a large boxy radiator or lots of casing ejector openings is bad from the drag point of view. Most aircraft in the 1930s looked like it, but most did move away from that and started using more streamlined radiators and fully faired undercarriage.



> you mean we'd have won the Battle of Britain by an even bigger margin?



British and German losses in the Battle of Britain were in fact very similar in absolute numbers, and the Spitfire in any case contributed much less to that than the numerous Hurricane. The Spitfire's major problem during development was high drag, that actually got worse as this was being compensated by more powerful engines (which ironically added even more drag with the new systems added like bigger radiators and intercoolers) and it was increasingly difficult to increase it's performance. Cleaning up the design a bit would have easily gained 30 and perhaps as much as 40 km/h.



> Who claimed that it was unique? And, if you check, the Meredith effect is air entering an intake, then expanding, which is what happened in the Spitfire radiator(s,) so let's have a bit less of this "so-called," please.



I think Siegfried is referring to that since Hugo Junkers described and used such a system many years before Meredith described it, the general attribution to Meredith is somewhat unfair.

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## Edgar Brooks (Nov 24, 2012)

Tante Ju said:


> I agree, figures would be interesting, but even without figures it is clearcut that semi-faired undercarriage, a large boxy radiator or lots of casing ejector openings is bad from the drag point of view. Most aircraft in the 1930s looked like it, but most did move away from that and started using more streamlined radiators and fully faired undercarriage.


Like the 109 190? And the ejector/muzzle openings were sealed shut, until the pilot opened fire.


> British and German losses in the Battle of Britain were in fact very similar in absolute numbers, and the Spitfire in any case contributed much less to that than the numerous Hurricane.


125 fewer, in fact - 530 to 655, achieved by 19 Squadrons against 33 Hurricane Squadrons. And if you add aircrew into your "absolute numbers," the Germans lost a lot more, so much that at least one German general said that it was their single most telling defeat.


> The Spitfire's major problem during development was high drag, that actually got worse as this was being compensated by more powerful engines (which ironically added even more drag with the new systems added like bigger radiators and intercoolers) and it was increasingly difficult to increase it's performance. Cleaning up the design a bit would have easily gained 30 and perhaps as much as 40 km/h.


Spitfire I flew at 362mph, and the XIV at 442, an increase of 80mph (128kph) or 22%, with an increase of 13000' in the service ceiling as well.


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## Shortround6 (Nov 24, 2012)

Try figuring the sea level speeds for a MK I and later aircraft (MK IX and MK XIV for instance) and seeing what power was used for what speed. Use the cube law to figure the power required and see how close they come out. 

According to the cube law a MK I going 336mph at sea level needs 1520hp if I have done the math right and 1870hp to do 360mph at sea level. How much power did a MK IX have at _SEA level_ and how much did a MK XIV have.

MK I with 880hp with constant speed prop and a sea level speed of 280mph used as base line.


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## Edgar Brooks (Nov 24, 2012)

Or, in other words, try to work out some way to fiddle the figures to get the result you want; play your games on your own.


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## Milosh (Nov 24, 2012)

Yes TJ be sure the Bf109E was as smooth as a baby's rear end. Even later 109s had all kinds of bumps, open wheel wells and tail wheels sticking out into the air stream.


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## Shortround6 (Nov 24, 2012)

Edgar Brooks said:


> Or, in other words, try to work out some way to fiddle the figures to get the result you want; play your games on your own.



We may disagree on the Whirlwind but the procedure I outlined actually works out rather well for the Spitfire. 

While the Merlin 65 or 66 in the MK IX was good for 1705 at 5750ft it was a lot closer to 1600hp at sea level (18lb limit). Theory says 80-100hp less is needed. MK I didn't have the external guns and certainly had smaller radiators, The MK I in the test didn't have pilot armor bullet proof windscreen is unknown but the plane only weighed in at 6,050lb so induced drag was less than the MK IX. I am seeing a bit more drag but not the big increase others are claiming. The MK XIV numbers are even more interesting, Theory says 1870hp needed, (for the light plane with no external gun barrels), While a Griffon 65 was good for around 2000hp at full thottle height in low gear it was good for around 1850hp at sea level at 18lbs boost (boost used for the 360mph speed in test). The MK XIV weighed 8400lbs in the test. this gives us a much heavier plane, more drag due to guns, yet the power for speed is coming out almost right on or just few % off, I am not seeing any big increase in drag for the later mark Spitfire here. 

I had done this exercise before and knew how it came out. Spitfire bashers are welcome to poke holes at it ( I am sure there are a few flaws) but I think it is better than "I think, it must have" and so on without even an attempt to show how the "extra" drag affects things.


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## Siegfried (Nov 25, 2012)

Edgar Brooks said:


> You have figures, of course?
> .
> you mean we'd have won the Battle of Britain by an even bigger margin?
> .
> ...



Let me answer your ‘protestations’ one by one.

One.
The battle of Britain wasn't won by the "iconic" Spitfire which in itself would have need the numbers of the Hurricane anyway, it was "thrown" by the strategic need to withdraw forces and put limited German resources into operation Barbarossa which itself was about cutting of a long term Soviet threat while securing the materials and strategic posture needed to form an defensible and economically autonomous Imperium Europa that might be able to take on the inevitable US/UK axis. Put simply Kriegsmarine was far too small, the Heer didn't have ANY amphibious assault capacity and the Luftwaffe had been prepared primarily as a tactical air force to support the most important German defence arm, the Heer and its need to deal with bordering countries.

Dealing with bordering French, Polish and Russian even Italian armies almost totally occupied German planning. Britain was a distant concern. In addition there were no strategies, significant plans or preparations for an air war against Britain let alone invading Britain. The only thing that might have made a difference is the proper preparation of drop tanks for the Me 109. There was more chance of invading the Soviet Union in short order than getting a force across the channel and defeating the RN in a short time scale.

Two
“Meredith” invented nothing. Hence the term “So called Meredith effect”. All he did was write an non-academic explanatory paper on heat recovery that became popular in the UK and perhaps US. The idea was reasonably known and started to make sense with the appearance of pressurised cooling loops which raised coolant temperature enough so as to allow smaller radiators.

Three.
Sorry for answering the question “what was good and what was bad” re Spitfire aerodynamics. A picture is worth a thousand words. Any Google image search of “Spitfire underside” versus “P-51 underside” will show how messy the Spitfire was in comparison. I would put the Fw 190 definitely in the much cleaner underside category. The Me 109 had its own issues caused by enlarged wheels and machine gun bulges (eventually rectified)

The retractable tail wheel versions (mainly Mk VII,VIII,XIV) were little produced in terms of overall numbers of 25000 spitfires. I stand by that statement. On the other hand all P-51 and Fw 190, P-47 and P-40 had retractable tail wheels as did all Me 109F, some Me 109G, Most Me 109K. Gun bulges, partially uncovered wheels, no less than 3 separate coolers, various antenna, non flush rivets(I believe) all marred the Spitfire underside. Never mind the P-51’s radiator system or laminar flow wings. Look at the underside of the Spitfire to reveal what is likely 10-20 mph of speed losses due to the superior construction values of the P-51 and more modern aircraft. Of course these things were likely known but production demands meant what appear to be trivial changes were not be made.


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## Tante Ju (Nov 25, 2012)

Edgar Brooks said:


> Like the 109 190? And the ejector/muzzle openings were sealed shut, until the pilot opened fire.



IMHO the 109/190 should deserve it's own thread, but in short the 109 improved considerably through the war from it's early state that represented the technology of the mid-1930s. The late 109s underside is effectively flush for example. The 190 did not evolve much, but it should be noted that it incorporated all the latest developments since it's birth.



> 125 fewer, in fact - 530 to 655, achieved by 19 Squadrons against 33 Hurricane Squadrons. And if you add aircrew into your "absolute numbers," the Germans lost a lot more, so much that at least one German general said that it was their single most telling defeat.



Well that's grand, and how does that view fit into the question of the Spitfire's drag exactly? I fail to see the relevance.



> Spitfire I flew at 362mph, and the XIV at 442, an increase of 80mph (128kph) or 22%, with an increase of 13000' in the service ceiling as well.



Yes, it improved very well, chiefly because they managed to put larger, heavier and more powerful engines to it. Well let's see the numbers.

The Spitfire I achieved 282 mph with about 880 HP, the Spitfire XIV achieved about 358 mph with 1840 HP at SL ('paper' figures, invidual planes may have flew faster or slower)

Since power requirement for speed increases on the cube, to drive a 282 mph plane to 358 mph you need (352/282)@3 = 1.94 the times of power, if all things are similar. That is 1.94*880 HP, or about 1710 HP, the amount of power a Spitfire I airframe would require to go as fast as the real life Mark XIV. As we can see by the XIV the increase in drag was equivalent to about 130 HP. BTW that 1710 HP is almost precisely what the Merlin 66 Spits had, so but those were only good for about 330 mph at SL. 

From that it follows that the drag increase during the development of the Spitfire was equivalent to about 25-30 mph speed loss. That's hardly insignificant.

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## Edgar Brooks (Nov 25, 2012)

Siegfried said:


> Let me answer your ‘protestations’ one by one..


1/. My "protestations" are corrections to your fabrications.


> One.
> The battle of Britain wasn't won by the "iconic" Spitfire which in itself would have need the numbers of the Hurricane anyway, it was "thrown"


Dear Lord, is there no end to your manipulation of history? So, now, we're to believe that the Battle was deliberately lost, and hundreds of elite German aircrew thrown away on a whim? Truly that means that the German hierarchy were even more incompetent than we first thought. Oh, and the Spitfire persuaded thousands of people, as far apart as Japan, South Africa, America and Argentina, to raise £5,000 for each aircraft (when the average weekly wage, in the U.K., was £1.5) to a total of over 1400 aircraft, so your "iconic" is a compliment, not an insult.


> Two
> “Meredith” invented nothing. Hence the term “So called Meredith effect”. All he did was write an non-academic explanatory paper on heat recovery that became popular in the UK and perhaps US. The idea was reasonably known and started to make sense with the appearance of pressurised cooling loops which raised coolant temperature enough so as to allow smaller radiators.


What Meredith wrote, in fact, was the germ of the idea for jet propulsion (and I have a copy of his letter, headed, "Invention relating to jet propulsion of aircraft," sent to the Air Ministry in 1935, taken from our National Archives, if you insist on arguing the point.)


> Three.
> Sorry for answering the question “what was good and what was bad” re Spitfire aerodynamics. A picture is worth a thousand words. Any Google image search of “Spitfire underside” versus “P-51 underside” will show how messy the Spitfire was in comparison.


But you didn't answer it, you simply made a rude comment about it. We have never-ending references to the "draggy" radiators, and I'm simply asking where are these references to be found? I've been through dozens of test reports, on the Spitfire (and other aircraft,) in our archives, and have never yet found one condemning the radiators; all I ask is where are these reports to be found? I have regular access to our National Archives, and should be able to find them, if you would just indicate where to look.


> The retractable tail wheel versions (mainly Mk VII,VIII,XIV) were little produced in terms of overall numbers of 25000 spitfires. I stand by that statement.


Out of 20,334 Spitfires (do stop massaging figures, there's a good boy) and 2,408 Seafires, 4,255 Spitfires and 786 Seafires had retractable tailwheels, which is a little over 22%, so not as insignificant as you like to make out.


> On the other hand all P-51 and Fw 190, P-47 and P-40 had retractable tail wheels as did all Me 109F, some Me 109G, Most Me 109K. Gun bulges, partially uncovered wheels, no less than 3 separate coolers, various antenna, non flush rivets(I believe) all marred the Spitfire underside.


Do show me where the three coolers are, under the Spitfire; in all my years, crawling under them, I've only ever found two. Your "belief" in non-flush rivets is another fabrication; the only area of domed rivets was on the fuselage, aft of the cockpit, and then only until June 1943. Allow me to tell you a little story, well-known among those who do bother to carry out research:-
K5054 was entirely flush-rivetted, but the process was expensive, so Supermarine glued half a dried pea onto every rivet, to see how a dome would affect the speed, then progressively removed lines of peas, checking as they went. It was found that domes made virtually no difference on the aft fuselage, but that was all, so the rest had to be flush. At the time (1936, remember) the technology for "blind" rivetting didn't exist, so every wing and tailplane rib had a strip of wood added underneath, to which the skins were fitted, using countersunk woodscrews, which were then filled and sanded smooth. When the ability to do so was available, rivets took over.


> Look at the underside of the Spitfire to reveal what is likely 10-20 mph of speed losses due to the superior construction values of the P-51 and more modern aircraft


. 
You're guessing again; got any figures to back that up? Oh, and the Spitfire employed exactly the same "construction techniques," namely filled and smoothed wing surfaces, plus smooth synthetic, rather than rough matt cellulose, paints, from August 1942.


> Of course these things were likely known but production demands meant what appear to be trivial changes were not be made


Yet another complete fabrication; I have a copy of the complete ledger of the modifications, carried out to the Spitfire and Seafire ( there were more than 2900,) which include production-shattering items like, ""To introduce adhesive tape for electrical cables," and "To secure egine data plate with bolts and nuts in place or rivets." Every single change had to go before, and be approved by, the Local Technical Committee (there was a war on, remember,) so stop talking nonsense, and *learn*.
In 1959 I went to work in a factory, which repaired Service vehicles, and, over every door, there was a sign "When in doubt, ask, don't guess," but I suppose the word "doubt" doesn't exist in your vocabulary?


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## Edgar Brooks (Nov 25, 2012)

Tante Ju said:


> Well that's grand, and how does that view fit into the question of the Spitfire's drag exactly? I fail to see the relevance.


Do me the courtesy of reading the statement, to which I was responding, before indulging in your latest bout of sarcasm.
.


> The Spitfire I achieved 282 mph with about 880 HP, the Spitfire XIV achieved about 358 mph with 1840 HP at SL ('paper' figures, invidual planes may have flew faster or slower)


It would be nice if you didn't blindly follow your pro-German mate:-
Spitfire I max speeds were 295 @ 2,000', 328 @ 10,000', 362 @ 18,500 (height of most interceptions in 1940,) and 315 @ 30,000'. The Merlin II produced 990hp @ 12,000' and 1060 @ 17,000'.


> Yes, it improved very well, chiefly because they managed to put larger, heavier and more powerful engines to it.


Which is a real (if not intended) compliment to Mitchell, because the 1935 airframe proved to be so adaptable, right through to 1950, (and, of course, the Germans never altered, or improved, their engines during the whole war.)


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## Shortround6 (Nov 25, 2012)

Tante Ju said:


> Well let's see the numbers.
> 
> The Spitfire I achieved 282 mph with about 880 HP, the Spitfire XIV achieved about 358 mph with 1840 HP at SL ('paper' figures, invidual planes may have flew faster or slower)
> 
> ...



Try again and see my post.
The Merlin 66 did not have 1710hp at sea level, it had 1705hp at 5750ft and had to use a partially closed throttle at sea level (much like the DB 605A puts out 1475ps at sea level but 1525-1550ps at a bit over 2000m). Merlin 66 was good for a lot closer to 1600hp at sea level. 
The 20mm gun installation was worth a few mph, drag yes but little to do with the "dirty underside". the increase in weight of over a ton means higher induced drag. We can account for 8-12mph just in the induced drag and guns (minimum), Between just those losses from drag and the actual power being lower than you figured the increase in drag from the "dirty underside" is heading for "insignificant" really quick.


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## Tante Ju (Nov 25, 2012)

Edgar Brooks said:


> Do me the courtesy of reading the statement, to which I was responding, before indulging in your latest bout of sarcasm.



Yes I have read it. Siegfried said the Spitfire's underside could use a bit of cleanup and that would be increasingly useful in the long term, to which you replied with a sarcastic and nationalistic fit about how much greater RAF glory (as you perceive the events) would have been in 1940 then. 

At this point I dared to point out that you are not making any sense. Did I miss something perhaps?


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## Edgar Brooks (Nov 25, 2012)

Shortround6 said:


> We may disagree on the Whirlwind but the procedure I outlined actually works out rather well for the Spitfire.
> I had done this exercise before and knew how it came out. Spitfire bashers are welcome to poke holes at it ( I am sure there are a few flaws) but I think it is better than "I think, it must have" and so on without even an attempt to show how the "extra" drag affects things.


My apologies if I was a little (!!!) short, earlier, but I'm growing tired of what you call "Spitfire bashers," who never produce anything to back up their "findings," or massage the available figures to suit themselves. If, during my years of research, I'd found anything, at all, condemning the radiators, I would say so, since truth is more important than Jingoism (of whatever nation.) Always, in the back of mind, there hovers the saying, "There are lies, damned lies, and statistics."


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## Edgar Brooks (Nov 25, 2012)

Tante Ju said:


> Yes I have read it. Siegfried said the Spitfire's underside could use a bit of cleanup and that would be increasingly useful in the long term, to which you replied with a sarcastic and nationalistic fit about how much greater RAF glory (as you perceive the events) would have been in 1940 then.
> At this point I dared to point out that you are not making any sense. Did I miss something perhaps?


Very definitely, since I was responding to your comment "and the Spitfire in any case contributed much less to that than the numerous Hurricane," not something written by our Australian-based pro-German, so try again. 
As for the "RAF glory," it's not just how I see it, but all the non-German-lovers, of this country, see it that way, as well, and, if you think that statistics are sarcastic, it could well explain your misuse of them.


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## Tante Ju (Nov 25, 2012)

Shortround6 said:


> Try again and see my post.
> The Merlin 66 did not have 1710hp at sea level, it had 1705hp at 5750ft and had to use a partially closed throttle at sea level (much like the DB 605A puts out 1475ps at sea level but 1525-1550ps at a bit over 2000m). Merlin 66 was good for a lot closer to 1600hp at sea level.



Well maybe this will help you. Merlin 66 had 1680 HP at SL (+18/3000), so my conclusions are still correct. There's no likely involved. Source British datasheet for Merlin 66, clearly noting SL power.

So the real question is - how much the Griffon 65 had at SL under static condtions? 1840 is for 400 mph ram. Likely the static condition is closer to 1900 HP at SL for Griffon. That means the aerodynamic effiency loss between the Mark I and Mark XIV is even slightly more severe.



> The 20mm gun installation was worth a few mph, drag yes but little to do with the "dirty underside". the increase in weight of over a ton means higher induced drag. We can account for 8-12mph just in the induced drag and guns (minimum), Between just those losses from drag and the actual power being lower than you figured the increase in drag from the "dirty underside" is heading for "insignificant" really quick.



Well let's see. 1 ton weight increase worth about 5 mph speed loss (from kurfurst.org site, for 109 but good ballpark for Spitfire.). Cannon installation - about 10 mph loss. Say another 5 mph for everything else - new antanne, changed shape winshield etc. 

That still leaves about 20 mph loss is due to things on the dirty underside. My take is that most of it is really coming from the much enlarged and doubled radiators.


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## Shortround6 (Nov 25, 2012)

Apology happily accepted. 

I like finding out the truth and I was a little surprised myself when I did this exercise a while back at how close it came out. It may be coincidence but it does seem to track fairly well. You can twist it a little by using the wrong power or a fast MK and a slow MK IX 9 or whatever) but I figure if the results at in the low single digits percentage wise it is close enough. Too much other stuff changes (windscreens, radial aerials,etc) in addition to individual aircraft performance to get any closer than that. 

As far as Meredith goes, many people have the same idea at nearly the same time without "copying" or even knowing about each other. Having the idea of using the heat from the radiator for propulsion may have been common, putting it into a mathematical formula and 'reading' the theory at an aeronautical convention was not common. I believe he proposed the use of exhaust thrust at the same meeting???
Again an _IDEA_ and a mathematical theory/formula are not quite the same thing and it takes a number of years to turn a theory/formula into actual practice so there may be credit enough to spread around. Not trying to take anything away from Meredith
but the constant arguments as to who "invented" what get a little tiresome when it takes 20-30 years for the "invention" to become practical. 
Shaft turbine engines were "running" before WW I. they just weren't very good  making claims for their "invention" years later a little strange. Claims for major improvements are a lot stronger.


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## Shortround6 (Nov 25, 2012)

Tante Ju said:


> Well maybe this will help you. Merlin 66 had 1680 HP at SL (+18/3000), so my conclusions are still correct. There's no likely involved. Source British datasheet for Merlin 66, clearly noting SL power.



Like this data sheet??

http://www.spitfireperformance.com/merlin66hpchart.jpg



Tante Ju said:


> So the real question is - how much the Griffon 65 had at SL under static condtions? 1840 is for 400 mph ram. Likely the static condition is closer to 1900 HP at SL for Griffon. That means the aerodynamic effiency loss between the Mark I and Mark XIV is even slightly more severe.



It doesn't really work that way. 18lbs boost is 18lbs boost. Ram can raise the altitude at which a given pressure can be maintained OR it can add pressure/power at lower lower altitudes. Static power is not going to be higher than RAM power unless something else is going on (like closing the throttle to limit the the amount of boost). In any case a hypothetical "static condition"has darn little to do with actual flight tests results. 





Tante Ju said:


> Well let's see. 1 ton weight increase worth about 5 mph speed loss (from kurfurst.org site, for 109 but good ballpark for Spitfire.). Cannon installation - about 10 mph loss. Say another 5 mph for everything else - new antanne, changed shape winshield etc.
> 
> That still leaves about 20 mph loss is due to things on the dirty underside. My take is that most of it is really coming from the much enlarged and doubled radiators.



"From that it follows that the drag increase during the development of the Spitfire was equivalent to about 25-30 mph speed loss. That's hardly insignificant."

Which is it? you just accounted for 20mph out of 25-30mph and yet you are claiming 20mph left of speed loss? 

NOBODY doubled the power of aircraft and didn't _some_ increase in drag. The question is how much. even 15mph is only about 4% on a 360mph airplane. I think I would take a 4% loss in potential speed due to drag in order to go from 280 mph to 360mph.


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## Edgar Brooks (Nov 25, 2012)

Tante Ju said:


> Well let's see. 1 ton weight increase worth about 5 mph speed loss (from kurfurst.org site, for 109 but good ballpark for Spitfire.). Cannon installation - about 10 mph loss. Say another 5 mph for everything else - new antanne, changed shape winshield etc.


Really don't know the Spitfire, do you? The XIV had a whip aerial, which gave less drag than the aerial mast, plus HF aerial wire, of the Mk.I, a thin bar-type Mk.III I.F.F. aerial, which gave less drag than the pair of Mk.II aerials of the early Marks, and the internal-armoured windshield, which also gave less drag than the externally-armoured type (introduced at the time of Dunkirk,) was introduced on the Mk.V, and never changed (except for the curved type on some P.R. variants) its shape throughout the war.


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## Siegfried (Nov 25, 2012)

http://spitfiresite.com/2010/04/supermarine-spitfire-variants-the-initial-merlin-powered-line.html/2
"All panel lines were filled and smoothed over, *all round headed rivets on the wing surfaces were replaced by flush rivets *and an elongated “racing” windscreen was fitted. A tailskid replaced the tail wheel. Finally the “Speed Spitfire” was painted in a highly polished gloss Royal Blue and Silver finish. As it turned out, the finished aircraft actually weighed some 298 lb (135 kg) more than a standard 1938 vintage Spitfire."

http://www.rcmf.co.uk/4um/index.php?topic=15309.0;wap
"According to an old MAP publication I own, from MK XII onward all rivets were of the flush type. Wing leading edge rivets back to the rear of the "D" section were also filled and sanded smooth as this area was found to have a pronounced effect on top speed."


Certainly I have read that the lower parts of the Spitfires wings were not flush rivetted, at some point anyway.

My statement that the retractable tailwheel versions was "little produced" stands, even by your own figures which claim 22%. My statement that production of the Spitfire was about 25,000 also stands if one includes the Seafire. Quite a few of those retractale tailwheel types were post war griffon engined Spitfire/Seafire. I would say that most folks can see through the squid ink of the hair splitting.

History of course records that few Spitfires had the retractable tailwheel and non had full wheel covers. Both would have had a significant impact on speed. Both were standard on most other fighters of the era.

Tests on the Me 109G indicated the following.

1 *Covering Up the Remainder of the exposed Wheels: +10kmh.*
2 *Retractable Tail Wheel over non retractable: +12kmh*
3 Extended Retractable Tail Wheel, if fitted +17kmh.
4 Loss due to MG 131 bulges -9 kmh.
5 Loss due to faired over MG 131 bulges -3 kmh.

Applying 1 and 2 above as indicative for the Spitifre we have a potential loss in speed of 22kmh, or about 13-14mph. 

That's no chump change and it was standard practice for the P-51 and Fw 190.

As far as the Battle of Britain goes: German strategy, for they had little time to develop one and had spent no specific money in preparing for it, was based around applying maxium credible pressure to force Britain to the negotiating table. Long term there was of course the possibillity of invasion, but it would have taken a great deal of time to get ready. In fact Hitler wanted Britain to keep its empire as he saw only someone worse taking it over should a German victory be used to liberate it to itself. An amphibious assault for which Germany lacked the Navy (paltry 36 submarines) would take a long time. By then the cabal of "human interest" journalists likely would have brought the US to Britains side and Germany would face the Soviets and the US/Britain. The gamble was to knock out the SU first. Perhaps a case of commiting suicide to avoid being killed as Bismarck suggested. Take out the fear of the US entering the war and the Soviet Union both German Navy and Lutfwaffe resources would have been applied and there would be no victory at the BoB, just historical notes about how the RAF had favourable attrition rates for a while but lost when tactics were changed.


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## Milosh (Nov 25, 2012)

You might want to take a look here Siegfried, contract summary

Grand Total: 22799 including Seafires, Spitefuls and Seafangs.


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## Edgar Brooks (Nov 26, 2012)

Siegfried said:


> http://spitfiresite.com/2010/04/supermarine-spitfire-variants-the-initial-merlin-powered-line.html/2
> "All panel lines were filled and smoothed over, *all round headed rivets on the wing surfaces were replaced by flush rivets *and an elongated “racing” windscreen was fitted. A tailskid replaced the tail wheel. Finally the “Speed Spitfire” was painted in a highly polished gloss Royal Blue and Silver finish. As it turned out, the finished aircraft actually weighed some 298 lb (135 kg) more than a standard 1938 vintage Spitfire..


The Speed Spitfire was the 48th production Spitfire, so quite what your point might be is rather lost; also it was flush-rivetted throughout, which is rather different from your nonsense about domed rivets, which never existed in the first place, *except on the rear fuselage*.


> "According to an old MAP publication I own, from MK XII onward all rivets were of the flush type. Wing leading edge rivets back to the rear of the "D" section were also filled and sanded smooth as this area was found to have a pronounced effect on top speed."


Unfortunately, MAP got it wrong (research moves on, as you'd discover if you tried it); the 100% flush rivetting started, from June 10th., 1943 with the Vc., and the wing + painting improvements started even earlier, from 25-9-42.


> Certainly I have read that the lower parts of the Spitfires wings were not flush rivetted, at some point anyway.


Not everybody gets their facts right, which is why it's best to find more than one source, and cross-check. The Mk.I had wooden strips on the bottom of the ribs, to which the skins were attached by countersunk (which equals flush) screws.


> My statement that the retractable tailwheel versions was "little produced" stands, even by your own figures which claim 22%. My statement that production of the Spitfire was about 25,000 also stands if one includes the Seafire


.
If you wish to repeat a falsehood, I can't stop you, though it reduces your credibility by a significant amount.


> Quite a few of those retractale tailwheel types were post war griffon engined Spitfire/Seafire I would say that most folks can see through the squid ink of the hair splitting.


Which proves what? You said they were few in number, and I said they were 1 in 5, and a fair number of the "post-war" Spitfires were already in production before the war ended, very suddenly, in September 1945, when everyone expected it to continue for much longer. If you're worried about the "squid ink of hair-splitting," perhaps you should stop using it.


> History of course records that few Spitfires had the retractable tailwheel and non had full wheel covers. Both would have had a significant impact on speed. Both were standard on most other fighters of the era.


History, of course, records nothing of the sort, since there were 3985 Spitfires with retractable tail wheels, out of 20,334, which = 19.59%, and the first fighters were some of the Mk.XII all VIII airframes (yes, they really were that early.) The 21, which just entered service in 1945, also had full wheel covers.


> Tests on the Me 109G indicated the following.
> 
> 1 *Covering Up the Remainder of the exposed Wheels: +10kmh.*
> 2 *Retractable Tail Wheel over non retractable: +12kmh*
> ...


No, "we" don't, since the VII, VIII, and XIV (slated to take over from the IX, which is why so many IXs were given away, especially to the USSR) all had retractable tail wheels, so your "loss" drops to just over 6mph, and that is "chump change," when you add in multi-ejector exhausts (gain of 5-7mph,) removal of ice guard (+ 3mph,) round, faired mirror, instead of square (+ 3mph.) cut-down ejection chutes (+ 1mph,) narrow, instead of broad, blister over cannon bay (+ 1mph.) You see, it wasn't just the super-efficient Germans who considered ways to improve aerodynamics.


> In fact Hitler wanted Britain to keep its empire as he saw only someone worse taking it over should a German victory be used to liberate it to itself.


So Britain would have surrendered, but still been allowed to run the Commonwealth? That's pure Hollywood-style fantasy, and you know it.


> An amphibious assault for which Germany lacked the Navy (paltry 36 submarines) would take a long time. By then the cabal of "human interest" journalists likely would have brought the US to Britains side and Germany would face the Soviets and the US/Britain.


Well, here goes "likely" (= guess) again.


> Take out the fear of the US entering the war and the Soviet Union both German Navy and Lutfwaffe resources would have been applied and there would be no victory at the BoB, just historical notes about how the RAF had favourable attrition rates for a while but lost when tactics were changed


Would've, should've, could've, here we go again, with the never-ending guesswork; try returning to the real world, and its ice-cold facts; we won, you lost.


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## Readie (Nov 26, 2012)

Edgar
Don't get sucked in mate.
Cheers
John


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## stug3 (Jan 4, 2013)

Spitfire Mark VII, BS142 on the ground at Eastleigh, Hampshire, after modification by Cunliffe Owen Aircraft Ltd., and shortly before joining the High Altitude Flight (renamed the Sub Stratosphere Flight) at Northolt, Middlesex. In January 1943, BS142 went to No. 124 Squadron RAF with whom it claimed the units first high altitude victory, a Focke Wulf Fw 190, on 15 May. It later also served with No. 331 Squadron RAF.






Group Captain A.G. ‘Sailor’ Malan on the wing of Squadron Leader Hugo ‘Sinker’ Armstrong’s Spitfire IX at Biggin Hill, 2 January 1943






Flight Lieutenant J. Pattison of No 485 Squadron, RNZAF, graphically recounts a combat to Squadron Leader ‘Reg’ Grant (left), and Flight Lieutenant R Baker (right), in front of a Spitfire at Westhampnett, 21 January 1943.


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## parsifal (Jan 4, 2013)

As ever stug, I love the photos


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## tomo pauk (Jun 11, 2015)

Recipe on getting the Spitfire V going 400 mph (also on speeding up the Mk.I and Mk.IX), provided by Kurfurst in an old thread. Interestingly enough, there is no mention of fully retractable covered U/C.


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## SpicyJuan11 (Jun 11, 2015)

tomo pauk said:


> Recipe on getting the Spitfire V going 400 mph (also on speeding up the Mk.I and Mk.IX), provided by Kurfurst in an old thread. Interestingly enough, there is no mention of fully retractable covered U/C.



What happened to him?


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## tomo pauk (Jun 11, 2015)

Banned.


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## SpicyJuan11 (Jun 11, 2015)

tomo pauk said:


> Banned.



Oh, does anyone know why, he seemed like a respectable poster?


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## blueskies (Jun 11, 2015)

Regarding the drag from wheel covers and retractable tail wheels I believe the following NACA reports are useful.

ntrs.nasa.gov/search.jsp?R=19930092668
ntrs.nasa.gov/search.jsp?R=19930092657

As for a boundary layer splitter for the radiator, there was one present on the speed spitfire and I believe that some type of splitter was also trialed on the mkiii. 

I would guess that they found the benefits of a splitter not worth the effort, similar to how messerschmitt dropped the duct on the 109.

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## fastmongrel (Jun 11, 2015)

SpicyJuan11 said:


> Oh, does anyone know why, he seemed like a respectable poster?



He couldnt resist using words and phrases that were rascist and derogatory. He got warned several times and then beached permanently, you can get away with quite a lot on this forum especially if you can back your claims but attacking others on the basis of country, creed or race is not allowed. Quickest way for the ban stick to hit you on the head.


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## fastmongrel (Jun 11, 2015)

blueskies said:


> Regarding the drag from wheel covers and retractable tail wheels I believe the following NACA reports are useful.
> 
> ntrs.nasa.gov/search.jsp?R=19930092668
> ntrs.nasa.gov/search.jsp?R=19930092657



Great info I have put them into links makes it easier to find.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092668.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092657.pdf


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## blueskies (Jun 11, 2015)

One finding in the first naca report is that a partially covered wheel well has a severe drag penalty due to air leaking into the wing. The report stresses the importance of properly sealing the well to eliminate leaks, and notes that a substantial gain will be seen if done correctly.

Edgar, do you know if the spitfire employed sealing in the wheel well? I'd imagine that there are a good number of related work orders if so.

Another point raised in the naca report is the thickness of the radio mast being responsible for most of the masts drag. Are there accurate drawings of the spits various masts?


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## Edgar Brooks (Jun 11, 2015)

blueskies said:


> Edgar, do you know if the spitfire employed sealing in the wheel well? I'd imagine that there are a good number of related work orders if so.


There's nothing mentioned, but a "stopper" was employed to fill the rivet "divots" on the wings' leading edges, so I'd hazard a guess the same material would have been used for any gaps.
The tyre was supposed to have only about half an inch clearance inside the well, and the wheel was half-covered by the cover. Full wheel covers were fitted to the prototype, but discarded, probably due to them snagging in grass-covered airfields.
The oleo covers sealed the leg channels, so any leakage was minimal.


> Another point raised in the naca report is the thickness of the radio mast being responsible for most of the masts drag. Are there accurate drawings of the spits various masts?


I've never seen any, sorry.
Edit: looking at available drawings, there was one for the mast which had the aerial set inside it (around the end of 1940,) but the RAF Museum's library don't list a copy.


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