No Spitfire?

Shortround6 said:

A large part of the Spitfires success and a large problem with trying to replace it with anything else that was on the drawing boards was that Mitchell and his team made the inspired guess to use the thin section wing. There was little or no hard data in England at the time to either support this or counter it. Just about everything else the British were designing used much thicker wing sections and the RAE had not yet figured out that there was a severe rise in drag at higher airspeeds (mid 300mph and up) which meant that many British designs ran into a wall and speed estimates were hopelessly optimistic.
Now in a "what if" we can postulate that another design team also selects a thin section wing but then we are dealing with a plane that never even existed on paper at the time.
Any design of the time using a thick section wing and using the Merlin engine of the time is going to be between the Hurricane and Spitfire in performance and probably closer to the Hurricane than the Spitfire.

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There was hard data in UK already in 1920s. The NPL (National Phisycs Laboratory) made a point in their official papers that, once airfoils get thicker than 15% t-tc, the drag of the said wings will be notably increased.
Unfortunately, that seem to went unnoticed, and people were trying to make ever better biplanes even in 1930s instead. Doh.

Seems like De Havilland was reading the good stuff, their Dh 88 Comet flew with thin wing already in 1934. Same with Percival, the Gull also flew in the same year. Granted, those were the racers, not combat aircraft, but still shows that there was enough of data to back up low-drag wings if anyone was interested.

Single seat Daffy has been gone over many times.
Basically we are supposed to believe that by removing the turret from the Daffy II (Merlin XX engine) the plane is supposed to go 30-40mph faster than the regular Daffy II when the
Prototype Daffy I showed no such difference in speed with and without turret.
Larger radiator and oil cooler on the Daffy II killed some of the anticipated improvement in speed.
I don't know if this was accounted for in the speed estimate for the single seat Daffy P.94
The P.94 Daffy was getting into the speed range at which the British were having a lot of trouble with accurate estimates.

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Not the fan, either.

tomo pauk said:

There was hard data in UK already in 1920s. The NPL (National Phisycs Laboratory) made a point in their official papers that, once airfoils get thicker than 15% t-tc, the drag of the said wings will be notably increased.
Unfortunately, that seem to went unnoticed, and people were trying to make ever better biplanes even in 1930s instead. Doh.

Seems like De Havilland was reading the good stuff, their Dh 88 Comet flew with thin wing already in 1934. Same with Percival, the Gull also flew in the same year. Granted, those were the racers, not combat aircraft, but still shows that there was enough of data to back up low-drag wings if anyone was interested.

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Trouble is that.......
Low drag = Low lift.
Low lift = Long take-off run
Multi-position props = work of the devil
Flaps = Shorter landing approach/run......Nothing to do with take-off.

Not absolute but a pretty good picture of Britain in the mid 30s.
Things changed (somewhat) by the late 30s.
You also had the weight/strength thing. A thick wing could be lighter than a thin wing of the same size/area and strength.

The British fumbled a bit with drag rise.

the start of the change in co-efficient of drag (Mcr) was at a slower speed than they anticipated.

The DH 88 and Mew Gull never came close to this speed.

So we all agree that we are going to just purchase the more superior P-39?

Shortround6 said:

Trouble is that.......
Low drag = Low lift.
Low lift = Long take-off run
Multi-position props = work of the devil
Flaps = Shorter landing approach/run......Nothing to do with take-off.

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Flaps with a few degrees down position were used on Spitfires overloaded with fuel during the take-off from carriers in 1942 (deployment to Malta).
Spitfire's wing's were both low drag and with good lift. Despite 13% t-t-c ratio at root. "The aeroplane is easy and normal to take-off. " - comment on the prototype, fixed prop in the nose. "Take off run 420 yds."; "Landing run with brakes 380 yds. " - for the service-worthy example, still with wooden prop.
But if the take-off distance for a fighter is the main measure of fighter's capability, let's stick with biplanes.

Not absolute but a pretty good picture of Britain in the mid 30s.
Things changed (somewhat) by the late 30s.
You also had the weight/strength thing. A thick wing could be lighter than a thin wing of the same size/area and strength.

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It probably could. But then again, Spitfire was fairly light and still tough, so we gain much more than we loose with thin wing.

The British fumbled a bit with drag rise.

the start of the change in co-efficient of drag (Mcr) was at a slower speed than they anticipated.

The DH 88 and Mew Gull never came close to this speed.

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The drag related to wing thickness mattered at speeds lower than the speeds we start connecting with Mcr. The relation between wing thickness and drag was noted much before compressibility was half-decently understood.
Plus, already the shipbuilders in the early 20th century knew that ships with lenght/beam ratio of 10:1 were faster than the ships with l/b ratio of 7:1, for same displacement, draft and horsepower.

DerAdlerIstGelandet said:

So we all agree that we are going to just purchase the more superior P-39?

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That depends. Have we removed the groundhog's face armor and given it more nuts?

tomo pauk said:

Flaps with a few degrees down position were used on Spitfires overloaded with fuel during the take-off from carriers in 1942 (deployment to Malta).

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Your proposition seems to be what could have been substituted for the Spitfire in 1936-37. What they were using as a "trick" in 1942 would have no bearing. What they were doing with the Spitfires off the carriers was cycling the flaps down, inserting wooden wedges that would hold the flaps at the desired angle, then closing the flaps on the wedges. Once airborne at a safe height the pilot cycled the flaps down to drop the wedges and then cycled them up for normal flight. This is hardly a stunt that would be approved in peace time for normal operations.

Spitfire's wing's were both low drag and with good lift. Despite 13% t-t-c ratio at root. "The aeroplane is easy and normal to take-off. " - comment on the prototype, fixed prop in the nose. "Take off run 420 yds."; "Landing run with brakes 380 yds. " - for the service-worthy example, still with wooden prop.
But if the take-off distance for a fighter is the main measure of fighter's capability, let's stick with biplanes.

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The Spitfire wing had good lift, but that was in part due to it's size and wing loading. Compared to a P-40 (no letter) the Spit weighed 1000lbs less or about 85% of the P-40 with a 2% more wing. The French D 520 had a wing about 70% the size of the Spitfire for roughly the same weight.

Take-off distance (or landing speed/distance) for a fighter is certainly NOT the main measure/s of a fighter's capability, BUT, if a fighter cannot operate from a majority of existing (or near future) fighter airfields it is pretty much useless despite whatever other attributes it may have. One reason (but certainly not the only one) for the Supermarine 224 not getting a production contract from the F.7/30 design competition was that it's landing speed of 60mph was 10mph higher than the specification called for. And that was with a 295 sq ft wing on a 4,750lb airplane.

The drag related to wing thickness mattered at speeds lower than the speeds we start connecting with Mcr. The relation between wing thickness and drag was noted much before compressibility was half-decently understood.
Plus, already the shipbuilders in the early 20th century knew that ships with lenght/beam ratio of 10:1 were faster than the ships with l/b ratio of 7:1, for same displacement, draft and horsepower.

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If drag was a simple progression then the estimates should have been more accurate. There doesn't seem to be quite the difference between planes of 300mph and under as there are for the 350-400mph planes planned in the late 30s. Something was causing a number of estimates from a number of different manufacturers to be off. They were starting to hit some compressibility (or flow incompatibility?) problems which affected drag.

The wind tunnel/s available to the British gave some rather flawed results at this time due to size and airspeed and it took a few years to straighten this out. Sidney Camm was told for instance " "no improvement in drag would be obtained by reducing the thickness-chord ratio of the wing below 20%."

Like I said earlier, unless some other design team makes an inspired guess (disagrees with official data) in 1934-46 you are unlikely to get a plane with a thin wing and comparable performance to the Spitfire.

Shortround6 said:

Your proposition seems to be what could have been substituted for the Spitfire in 1936-37. What they were using as a "trick" in 1942 would have no bearing. What they were doing with the Spitfires off the carriers was cycling the flaps down, inserting wooden wedges that would hold the flaps at the desired angle, then closing the flaps on the wedges. Once airborne at a safe height the pilot cycled the flaps down to drop the wedges and then cycled them up for normal flight. This is hardly a stunt that would be approved in peace time for normal operations.

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That was a necessity to do since IIRC there was no a range of flap angles, but a 'binary' mode - either drooped or retracted. Going with a flap retracting system with a few in-between 'pre-sets' would've been good.

Shortround6 said:

The Spitfire wing had good lift, but that was in part due to it's size and wing loading. Compared to a P-40 (no letter) the Spit weighed 1000lbs less or about 85% of the P-40 with a 2% more wing. The French D 520 had a wing about 70% the size of the Spitfire for roughly the same weight.

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No quarrels about that, I have no desire to suggest going with a smaller wing for a 'no Spitfire' anyway, at least not unless we have a good case for a company introducing Fowler flaps for it at 1937-38 time frame.

Shortround6 said:

If drag was a simple progression then the estimates should have been more accurate. There doesn't seem to be quite the difference between planes of 300mph and under as there are for the 350-400mph planes planned in the late 30s. Something was causing a number of estimates from a number of different manufacturers to be off. They were starting to hit some compressibility (or flow incompatibility?) problems which affected drag.

The wind tunnel/s available to the British gave some rather flawed results at this time due to size and airspeed and it took a few years to straighten this out. Sidney Camm was told for instance " "no improvement in drag would be obtained by reducing the thickness-chord ratio of the wing below 20%."

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Sir Sidney should've said to himself - proof is in the pudding. The racing monoplane aircraft from Supermarine, Macchi, D-H, Percival were a known quantity for people in the business. I-16 was known in the west by late 1934. All these aircraft have had one thing in common - thin wings and high speeds. There is Bf 108 around. Yet, Sir Sidney made the same mistake with Typhoon, despite all of that and British reports on BF factory noting that new fighter (Bf 109) will have thin wing for greater speed. Ever increasing speed was mandatory thing for the fighters back in 1920s/30s/40, not something that was optional.

Then we have the radiator thing, where only Miles ( with Kestrel-powered Master), was capable to out-do Hawker with how faulty a radiator can be installed for more drag than it was bargained for.

tomo pauk said:

That was a necessity to do since IIRC there was no a range of flap angles, but a 'binary' mode - either drooped or retracted. Going with a flap retracting system with a few in-between 'pre-sets' would've been good.

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It would have been good, but it wasn't what was being done at the time by most companies. Hurricane flaps.

Flaps at this point in time were basically air brakes. not lift producing devices. By 1942 you had the double slotted Fowler flaps so a lot changed in 6 years. All the Zap Flaps, Youngman flaps, Junkers flaps came in-between so even a year or two made a difference.

No quarrels about that, I have no desire to suggest going with a smaller wing for a 'no Spitfire' anyway, at least not unless we have a good case for a company introducing Fowler flaps for it at 1937-38 time frame.

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And here is part of the problem, if you don't have the Spitfire and take another 1935-37 (flying during those years) airframe you are stuck with the technology of the time. IF you wait until 1937 to put pen/pencil to paper you won't get any real number of aircraft to the service squadrons in 1940.
Lockheed Hudson but the Electra 14 was the first plane to use Fowler flaps.

They cannot be added to an existing wing. The wing has to be designed to use them from the start. Rear spar location and strength has to be worked out.

Sir Sidney should've said to himself - proof is in the pudding. The racing monoplane aircraft from Supermarine, Macchi, D-H, Percival were a known quantity for people in the business. I-16 was known in the west by late 1934. All these aircraft have had one thing in common - thin wings and high speeds. There is Bf 108 around. Yet, Sir Sidney made the same mistake with Typhoon, despite all of that and British reports on BF factory noting that new fighter (Bf 109) will have thin wing for greater speed. Ever increasing speed was mandatory thing for the fighters back in 1920s/30s/40, not something that was optional.

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Well, we have reports of what other countries were doing and we have reports from the national research institutions. Which actually changed quite a bit from 1934 to 1936 but still not quite enough.
You can also make a thin wing low drag "racing plane" that does 200-250mph but when you scale it up and fit bigger engine and try for 375mph you run into a wall at around 340-350mph. This is because local airflows, like between the fuselage and wing root are at different speeds and when they attempt to mix/join they cause drag. This is one reason for the large wing root fillets on some planes, some worked better than others. As you note, some radiators were better than others.

Shortround6 said:

Lockheed Hudson but the Electra 14 was the first plane to use Fowler flaps.

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Indeed it was so.
Looks like Mr. Fowler patented his flaps as early as 1924.

Shortround6 said:

You can also make a thin wing low drag "racing plane" that does 200-250mph but when you scale it up and fit bigger engine and try for 375mph you run into a wall at around 340-350mph. This is because local airflows, like between the fuselage and wing root are at different speeds and when they attempt to mix/join they cause drag. This is one reason for the large wing root fillets on some planes, some worked better than others.

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Thin wings are the wings with low thickness-to-chord ratio. Eg. 15% and under at the root, at least in 1930s-40s. Scale up a small thin wing, and the new wing it is still a thin wing.

To be honest the best idea I can come up with is concentrate on the Hurricane and Gloster whilst upping the Whirlwind which should get you through the BOB then go defensive until you can get your hands on the Mustang designed with the Merlin from the start.
If you get really lucky, the Typhoon can sort out its reliability issue and be a good response to the Fw190

tomo pauk said:

A what-if situation emerges where, for this or that reason, Spitfire as we know it (= a fast 1-engined fighter by Supermarine, company's Type 300, conceived in second half of 1930s) never sees the light of the day. What should RAF do, either via the British companies or otherwise, to 'plug the gap' between Hurricane and next-gen fighters that were supposed to materialize as Typhoon/Tornado? Especially in late 1940-early 1943 time frame, when Spitfire was the #1 WAllied fighter. What companies should be favored? More than 1 answer to the situation can be given

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If the Spitfire is proposed, but not accepted for production, Supermarine would most likely be working on an improved model for future requirements. Or they could give up on the S/E market and concentrate on the Type 324 and Type 327, submitted in 1937 and 1938, the former competing against the Hawker Tornado/Typhoon, the latter as a 4 cannon fighter to back up the Whirlwind (production went to Beaufighter).

One of the reasons given for not giving Supermarine a development or production contract for the 324/327 was that they were slow to build prototypes and bring them to production. With the Spitfire having not been given a production contract, the Air Ministry does not have that experience, so more likely to give Supermarine a contract?

Or would Supermarine concentrate on the Type 316?

tomo pauk said:

Thin wings are the wings with low thickness-to-chord ratio. Eg. 15% and under at the root, at least in 1930s-40s. Scale up a small thin wing, and the new wing it is still a thin wing.

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You are quite right, but the problems that were affecting some British planes in that 350-400mph region DID NOT show up at speeds in the 200-250mph region.
The wings on the Schneider trophy racers were external braces (with wires) except for the Gloster monoplane of 1925 which crashed due to wing flutter.
Mitchell and the Crew at Supermarine went for the thin wing, but none of the other big airplane makers did for the most part. DH was trying to break into the "big" airplane market and out of the small aircraft market, which they did dominate.
The DH 88 was a special racing plane and could compromise certain areas of performance for other areas of performance. It would have needed all kinds of modifications to become a service aircraft of any sort (even a recon plane).

Shortround6 said:

Mitchell and the Crew at Supermarine went for the thin wing, but none of the other big airplane makers did for the most part.

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Not in the UK, indeed.

Shortround6 said:

The DH 88 was a special racing plane and could compromise certain areas of performance for other areas of performance. It would have needed all kinds of modifications to become a service aircraft of any sort (even a recon plane).

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I've noted the DB 88 just as an example that there was enough of theoretical knowledge in the UK proper, the knowledge pointing out to what kind of wing can be conductive for lower drag and thus greater speed. D-H will need to apply both theoretical and practical knowledge - gained now with DH 88 project - in the new fighter project, not just 'kit bash' the DH 88 into a combat A/C.

We are back to field requirements and other requirements.
Percival themselves reverted to a thicker wing than the Mew Gull on the Q-4and Q-6 light transports.

flew 3 years after the Mew gull.

Perhaps another design team would have used a thin wing if Supermarine didn't. However it would change whatever design they applied it to so much that trying to estimate performance or effectiveness of such a design would be pure guess work.

No Spitfire and it's not ideal.

Tempest/Typhoon? Time scales are wrong.

Gloster Zero or something else? More Defiants? Single seat Skua? Miles M.20? Not exactly first class.

I wouldn't ask the French as they had nothing better than a Hurricane. Americans are P-36? F4F? Merlin P-36? V-143?

Obviously licence deal on the Brewster Buffalo is top dog. There is a few American mid 30s designs like the P-35 which may look attractive.

Build the Bf 109 under licence?

Fokker had some interesting aircraft but again no Spitfire replacement.

Spitfire replacement for Battle of Britain is a no. Mediocre replacement is a big yes. Just pick a random and hope it's not too terrible.

The Basket said:

Americans are P-36?

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Keep in mind that the French Hawk 75 accounted for more victories over the Luftwaffe during the Battle of France than any other type - the P-36 may have been a "mid 30's design", but so was the Bf109.

P-36 with a Bristol engine or P-40 it up with a Merlin in time for BoB?

No Spitfire and anything and everything decides to appear out of the woodwork.

That's probably one legacy of the Spitfire that's overlooked....it's stopped a bunch of junk from happening.

Shortround6 said:

We are back to field requirements and other requirements.

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I'm not sure that there is a point in further discussion about the merits of a thin wing.

The Basket said:

P-36 with a Bristol engine or P-40 it up with a Merlin in time for BoB?

No Spitfire and anything and everything decides to appear out of the woodwork.

That's probably one legacy of the Spitfire that's overlooked....it's stopped a bunch of junk from happening.

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The problem with any American design is that it would have to be licence-built in the UK. There's no way shipments across the Atlantic could keep up with the attrition faced during the BoB without considerable manufacturing infrastructure in the UK.

Quantity v Quality.

Yeah you could build a fighter but you ain't building a Spitfire.

Odd that the driving force was the 109 but no Spitfire then no 109?

Has uk ever built an American aircraft? Can't think of one. Although the Americans have built a few British. Canberra, Hawk, Harrier, P-51.....