Long range, high speed Spitfire fighter: the best approach?

zjtins said:

The problem no one seems to consider is the lack of raw material. Germany had lots of Iron and Coal. They could make some forms of steel. At best they might have increased the output for a short while, but once a critical material was gone their design had to change to accommodate less capable metals.
Germany by 44 and maybe late 43 was making aircraft propellers out of wood, the ME109 had a wood tail (or portions). For tanks face hardened armor was almost gone, chrome was gone from gun tubes, they had to invent the use of steel casings for rounds due to copper shortage (more weight less reliable then brass), etc.

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The Germans had various shortages of critical alloys, but few that would effect aircraft production. Wood was sometimes used for propellers since the war's beginning, because it had some advantages over metal props, it was entirely out of choice. Wooden compontents were used not because of aluminium shortage (Germany was the 2nd largest producer after the US) but because it allowed the use of skilled woodworking shops for the aircraft industry. Copper was in short supply as was chromium (Turkey) and nickel (Finland) but it was not critical until the wars end; OTOH face hardened armor was simply dropped because it was not practical for the increased armor thicknesses, which called for more softer and more ductile armor that resisted rounds better, and techniques such as sloped armor (besides face hardening being time consuming and more of a question of capacity, rather than alloy). Some alloys were dropped from armored steel but were substituted by others (rather expensive, but available vanadion was used instead of molybdenium, but vanadium is also a very effective alloy). Most alloys in steel industry are replacable by others.

In the end, weapon production was never critical, though hurt by Allied bombing, the Germans always had plenty of guns. Their critical bottlenecks were fuel (which was hurt by the SBC as much as by the Red Army's advance, the latter also effected some critical alloy supplies in Ukraine) and manpower.

I think you mean dispersed, not disbursed.
Dispersion of the subassemblies manufactoring introduces new problems. You have to transport the parts on a schedule, otherwise you have a lot of subassemblies waiting around somewhere waiting for other parts that have to installed first.
Sort of like the "just in time" method of manufactoring used by a lot of car manufactors today, it saves them from having to store parts in warehouses, instead the parts arrive right when they're needed, not too early, in which cased they'd have to be stored somewhere, and certainly not too late, which would mean the production line has to be stopped.
Plus when making subassemblies in different places by different manufactors especially if under rough conditions, tolerances tend to get sloppy.

I think you mean dispersed, not disbursed.

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Thanks I grabbed the wrong word on auto correct.

The Germans had various shortages of critical alloys, but few that would effect aircraft production. Wood was sometimes used for propellers since the war's beginning, because it had some advantages over metal props, it was entirely out of choice. Wooden components were used not because of aluminum shortage (Germany was the 2nd largest producer after the US) but because it allowed the use of skilled woodworking shops for the aircraft industry.

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Germany had zero bauxite mines in country ore came from countries they captured including, Hungary, Rumania, Yugoslavia. Now you know why Hitler took those countries.

I did not list all metals for hardening but even as early as August 1944 German tanks on the western front were taking hit and shots penetrating that were later written penetrated up as: cause due to weak armor. There are accounts of some was so bad the armor shattered.

They were running low so props, tail planes, flaps started to appeared at different times.

Maybe the German war production discussion should go in a thread of it's own, since it's way off topic here?

Make the title: "Revisionist History 101" or even better "WWII: Just Another Day At the Office".

Maybe the German war production discussion should go in a thread of it's own, since it's way off topic here?

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True

Long range-high speed Not sure what you are looking for but as compared to a P-51H why continue with a Spit? Money wasted unless as that was approaching the best you can get in a liquid cooled piston engine fighter of the time.

Only the P47 versions with 3000 hp engines, DO-335 and possibly a P-38 with Merlins with matching props would do better (that come to mind). But all of those are at the cost for maneuverability as compared to the P-51, more of interceptors vs fighters. (also the F7F)

P-51H was a little to late to make much of a difference anywhere.

The period being talked about is 1943 into 1944, when escorts were at a premium.

Spitfire XIV would kick the arse of the P-51, P-47 or P-38 in a fight in early 1944. If only it could get somewhere useful.

I note in the report on WWII Aircraft Performance that it was considered that the XIV was superior to the German opposition even with the slipper tank in position.

Well higher speed was not in the cards due to the thick wing. Moving to laminar flow would move it into 44 when the H model was about to be developed. Also moving to laminar wing loses the Spits turning performance in the flight regimens it was famous for. Finally it still lacked the ability to mount 4x20mm cannon so it was firepower limited.
To solve all of that would take more than a few months, and in fact later real versions never did solve that

zjtins said:

Well higher speed was not in the cards due to the thick wing.

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Spitfire have had thick wing??? Any numbers to back up the calim?

Moving to laminar flow would move it into 44 when the H model was about to be developed. Also moving to laminar wing loses the Spits turning performance in the flight regimens it was famous for. Finally it still lacked the ability to mount 4x20mm cannon so it was firepower limited.

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The ability to mount 4 cannons was there in 1941. Even with 2 x 20mm and 2 x .50, it's firepower was better than any Merlin Mustang, and comparable with any US fighter with R-2800 in the nose.

To solve all of that would take more than a few months, and in fact later real versions never did solve that

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Fact is that British have had modified some Spitfire IXs to carry circa 160 imp gals of internal fuel, in second half of 1944. Check out the 'RAF's long range fighters' thread in this sub-forum. Laminar flow wing would be a good addition, but they could've earned speed with refinement of raditor systems, fully enclosed main wheels, retractable tail wheel etc.

The Spit wing had smaller t/c ratio than any front line fighter. That is a fact easily validated with simple look ups. That is the Sole reason a spit could achieve a higher Mcr than both the P-51/P-47/Bf 109 and Fw 190 in a dive. The Actual wing thickness of the Spit where the 20mm were mounted is greater than the 15% T/C for the 45-100 because of the deep chord of the Spit wing compared to the P-51.

The Spit had higher drag CDo than both the Mustang and the FW, particularly the D-9.

Zjtins - the only credible thing you said was that if a laminar flow wing replaced the Spit wing airfoil, that such replacement - all else equal- the CLmax would be less and Turn performance would be reduced somewhat - but given the same comparison it should still out turn the P-51, Fw 190 and Bf 109 except perhaps at speeds below Corner speed.

drgondog said:

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The Spit had higher drag CDo than both the Mustang and the FW, particularly the D-9.
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Bill - what would be the CD0 value for Fw-190D-9?
The British credited Spit Vb with CD0 = 0.0213, Spit Vc = 0.0218, Spit IX = 0.0238; respective drag force ("total profile drag D0 100 (lb at 100 fps)") being 61, 63 and 66 lbs.
For Fw-190A they give CD0 = 0.0269, drag force being 65 lbs.

tomo pauk said:

Bill - what would be the CD0 value for Fw-190D-9?
The British credited Spit Vb with CD0 = 0.0213, Spit Vc = 0.0218, Spit IX = 0.0238; respective drag force ("total profile drag D0 100 (lb at 100 fps)") being 61, 63 and 66 lbs.
For Fw-190A they give CD0 = 0.0269, drag force being 65 lbs.

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Good points. What people seem to forget that the Spit's drag was pretty good compared to most of the other planes of the era. It wasn't particularly draggy by any means.

It was just the fact the Mustang was so good and was exceptional for that era (until the later 'super' planes like the Hornet, etc, came on the scene).

No doubt Mustang was the exceptional execution.

For Spitfire, we can see that CD0 increased almost 12%, IX vs. Vb (= same armament). Main culprit being the addition of inter-cooler radiator?
Further - with better layout of whole radiator system (oil, engine, i.cooler), say, in leading edges, the CD0 goes close/under the 0.0200 mark?

tomo pauk said:

No doubt Mustang was the exceptional execution.

For Spitfire, we can see that CD0 increased almost 12%, IX vs. Vb (= same armament). Main culprit being the addition of inter-cooler radiator?
Further - with better layout of whole radiator system (oil, engine, i.cooler), say, in leading edges, the CD0 goes close/under the 0.0200 mark?

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Supermarine proposed modifying the Spit to move the radiator to under the fuselage (ah lah the Mustang) but MAP (Ministry of Aircraft Production) canned it as it would disrupt production too much..

Basically RR came coming to the party with ever more powerful engines and MAP took the pragmatic view that it was easier to follow that route than make major changes. Can't blame them.
If, RR hadn't been able to do that then they might followed a different path.

Interesting top compare the wind tunnel test of the Spit I and Mustang I. These just map the basic shapes, without the issue of things like of radiator efficiency effects, finish, etc. Plus they were on the same wind tunnel, so any distortions were common to both.

At zero coefficient of life (CL=0) the Mustang was much less draggy than the Spit, with a CD of about 0.15, while the Spit was about 0.18
At low CL (0.2) they were roughly the same at just under 0.02 up to about mach 0.7. At mach 0.75 the Spit is about 0.32 while the Mustang is about 0.38.
At CL 0.4 again very similar up to about mach 0.5, then the Spit starts to become better than the Mustang. At mach 0.7 the Spit is significantly better than the Mustang with a CD of 0.3 vs 0.34 . At mach 0.75 the Mustang is about 0.61 vs the Spit at about 0.55.


Note: all numbers can be a bit uncertain (plus or minus a bit) as I'm reading it off charts.
Some other interesting observations, the CD of the Spit was very similar for CL 0 to CL 0.2, while the Mustang shows significant difference.

In the high mach (0.7+) region the Spitfire was consistently better, with the gap growing as the mach rose (to 0.75 or 0.8 ).

So there was nothing wrong with the Spits shape (wings, fuselage, tail) difference came from the radiator system and details. In some areas (like tail area) it was better. The wings were probably about the same, up to high mach when the Spit's wing is better. The Engine cowling and intakes were better on the Mustang (beautiful low drag front).

Details matter a lot, the flat bulletproof windscreen cost the Spit 5mph, cannons on later models cost it another 5mph. The finish of the Mustang was far better (when new), not just the tailwheel and wheel covers, but the overall fit an finish. The Mustangs radiator had very low drag in most flight regimes and the faster it went the better it was. The Spit's (and this was a Spit I) much worse, made even worse when they went to twin radiators.

Other interesting facts: The Spit used 2 types of wing section. NACA 2213 at the root, 2208 near the tip. So not only did it get thinner the further you got out and had wing twist, the section changed (I think this was to reduce wing twist drag).

tomo pauk said:

Bill - what would be the CD0 value for Fw-190D-9?
The British credited Spit Vb with CD0 = 0.0213, Spit Vc = 0.0218, Spit IX = 0.0238; respective drag force ("total profile drag D0 100 (lb at 100 fps)") being 61, 63 and 66 lbs.
For Fw-190A they give CD0 = 0.0269, drag force being 65 lbs.

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Tomo - I don't have them offhand, but the Lednicer report had the Fw 190D Flat plate Drag at 4.77 to to Spit IX 5.4 and the P-51D at 4.61. I'll have to re-check the report to see the altitude and speed that the flat plate drag was calculated.

If you have a published (reliable) flight test with GW, top speed at SL and rated Hp of the engine I can calculate it, or in the case of the Lednicer report noted above, the GW of the FW 190D for which the Drag was cited - I can extract that.

The Total Drag can be extracted from Lednicer if altitude and airspeed is say 360kts at 15000 feet - but need GW to extract Induced Drag to subtract from the Total Drag to get Parasite Drag...

OldSkeptic said:

Good points. What people seem to forget that the Spit's drag was pretty good compared to most of the other planes of the era. It wasn't particularly draggy by any means.

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Actually the Spit was one of the draggiest s/e fighter planes of the era, this is why it was so short ranged... even the lowest Cd0 fgiven for Mk Vb of CD0 = 0.0213 means that the total equivalent drag of the aircraft was 5.15 sq. feet, for the for Mk IX of CD0 = 0.0238 means that the total equivalent drag of the aircraft was 5,76 sq. feet. And that's a lot.

Don't mix Cd0 with "dragginess", cd0 is usually understood as a coefficient for wing area only.

OldSkeptic said:

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Note: all numbers can be a bit uncertain (plus or minus a bit) as I'm reading it off charts.
Some other interesting observations, the CD of the Spit was very similar for CL 0 to CL 0.2, while the Mustang shows significant difference.

In the high mach (0.7+) region the Spitfire was consistently better, with the gap growing as the mach rose (to 0.75 or 0.8 ).

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Any chance that charts might be posted here?

So there was nothing wrong with the Spits shape (wings, fuselage, tail) difference came from the radiator system and details. In some areas (like tail area) it was better. The wings were probably about the same, up to high mach when the Spit's wing is better. The Engine cowling and intakes were better on the Mustang (beautiful low drag front).

Details matter a lot, the flat bulletproof windscreen cost the Spit 5mph, cannons on later models cost it another 5mph. The finish of the Mustang was far better (when new), not just the tailwheel and wheel covers, but the overall fit an finish. The Mustangs radiator had very low drag in most flight regimes and the faster it went the better it was. The Spit's (and this was a Spit I) much worse, made even worse when they went to twin radiators.

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Be it as it is, the completely covered wheels help Mustang too.

Other interesting facts: The Spit used 2 types of wing section. NACA 2213 at the root, 2208 near the tip. So not only did it get thinner the further you got out and had wing twist, the section changed (I think this was to reduce wing twist drag).

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The NACA 2213 should mean that wing belongs to the NACA 2200 profile, 13% thick; 2208 is, again NACA 2200 profile, 8% thick.

Tante Ju said:

Actually the Spit was one of the draggiest s/e fighter planes of the era, this is why it was so short ranged...

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Nope, it was short ranged when carrying 85-95 gals of fuel.

even the lowest Cd0 fgiven for Mk Vb of CD0 = 0.0213 means that the total equivalent drag of the aircraft was 5.15 sq. feet, for the for Mk IX of CD0 = 0.0238 means that the total equivalent drag of the aircraft was 5,76 sq. feet. And that's a lot.

Don't mix Cd0 with "dragginess", cd0 is usually understood as a coefficient for wing area only.

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Yes, let's not mix up stuff.
Let's go straight to the point and say that Spitfire have had far more wing area than, say, Yak fighters, La fighters, MC fighters, Bf-109... Even the Fw-190 have had ~15% less wing area. Size matters - that's why Yak-3, MC.205 and Bf-109 were capable to make circa 650 km/h even on, for mid and late war standards, modest power. We can compare MC.202 and Re.2001, and MC.205 and Re.2005 - there was no way for Regianne to be faster than Macchi, since the Re. have had more wing wetted area.

So we can compare Spitfire with Ki-61, Re-2001/5, G.55 and THEN come to conclusion what airplane was draggy or not. And we can also note that such planes were capable to carry multiple internal cannons and generous fuel when tasked, no problems - contrary to Yaks, Bf-109 or MC.202/5. In other words, there aint such thing as free lunch.
Almost forgot - Spitfire was also able to carry the heavy powerful Griffon, again without problems. Maybe it would be the best not to try that with small, 'undraggy' fighters?

Tante Ju said:

Actually the Spit was one of the draggiest s/e fighter planes of the era, this is why it was so short ranged... even the lowest Cd0 fgiven for Mk Vb of CD0 = 0.0213 means that the total equivalent drag of the aircraft was 5.15 sq. feet, for the for Mk IX of CD0 = 0.0238 means that the total equivalent drag of the aircraft was 5,76 sq. feet. And that's a lot.

Don't mix Cd0 with "dragginess", cd0 is usually understood as a coefficient for wing area only.

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Tante Ju - Strictly speaking CDo is the total Parasite Drag at zero lift (to remove Induced Drag component).. so it encompasses Friction Drag, Form Drag, etc - literally everything but drag due to lift (i.e wing twist, LE slats, Flaps, Wing Body lift)

Having said this, you are absolutely correct that CDo is expressed as a function of Wing Area..

For some real simple comparisons of drag see Spitfire vs Hurricane, Spitfire V vs P-40F.

And lets not forget that at various cruising speeds and various altitudes the Spitfire V swapped back and forth with the 109F-4 as to which used the least fuel to cover 100 miles. Not strictly drag but total propulsive efficiency and they were usually within a few % of each other. Not bad for a "big, draggy" airplane.