Most discussions are about the statistical performance of the Spitfire, which are true and cannot be argued with, it was a better aircraft, it is also true that solely with Spitfire numbers in service in Sept 1939, and May 1940 the UK didn't have an air force or any chance of having one. Despite the numbers sold and sent abroad, lost in training accidents and in France, from the start of the BoB when numbers were equal at 250 each the Hurricane outnumbered the Spitfire. I don't care if people don't agree with a fact, that is their problem, that's the way it is, it was the Hurricane that made the issue about pilot number and quality.
No Spitfire?
- Thread starter tomo pauk
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Thumpalumpacus
Major
I don't think that, lacking the Spitfire, the Brits were in any mood to say "Right-o, chap, that's it, let's have a spot of tea." They knew they needed something better even before the first Hurri came off the lines, and were working on it. They weren't dummies, and the pressure of the time was pushing all designers to stretch the envelope.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Then aparently, Britain's only option is to surrender...
Not surrender but with no Spitfire or Spitfire replacement they cannot go on the offensive in any theatre, as I have said numerous times the RAF is effectively neutered.
Admiral Beez
Major
That's only relevant if we assume the fallacy that one change doesn't ignite others. If there's no Spitfire, what has replaced it? We can't even limit ourselves to known candidates like the Bristol 146, Vickers Venom or Gloster F5/34.
No Spitfire means Mitchell and all the other British designers are hurriedly sketching new designs to fill Air Ministry Specificafion F.37/34 calling for a "High Speed Monoplane Single Seater Fighter". I'd expect to see a Hercules powered single engined proposal, for example.
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wuzak
Captain
The specification F.37/34 was, essentially, written around the Supermarine Type 300.
No Spitfire, no F.37/34?
Admiral Beez
Major
Yes, but in this storyline presumably the Air Ministry didn't like what they saw, thus cancelling out specification F.10/38. We don't know why or how the Spitfire doesn't happen, but this is a plausible route.
IDK, the RAF still needs to fill the Spitfire's need, so I could see another Spec being issued to the aircraft designers.
Who knows? Maybe no Spitfire gives us the Meteor a few years earlier.
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wuzak
Captain
The Type 325 was one of two designs put forward for F.18/37, the specification that led to the Tornado/Typhoon, the other being the Type 324, which was essentially the same, but with tractor propellers.
Both could use the Merlin or Taurus.
The Type 327 was a further development with 6 cannon armament.
Shortround6
Major General
Quite true as we know or can pretty well estimate that none of the real world actual flying prototypes were going to equal the Spitfire, so whatever Spitfire replacement people can come up with for this scenario is a total unknown.
Part of the problem with the hypothetical fighters is there was only one suitable engine at the time (or for several years). The Merlin.
Nobody at the time knew the Bristol Taurus was never going to be given the resources needed to make it a viable engine. Viable in sense of making competitive power at over 10,000ft.
Whatever it may or may not have done as a torpedo bomber engine at sea level to 4,000ft is rather immaterial to a Spitfire I & II replacement.
The Hercules III (first with a two speed supercharger) was good for 1250hp at 16,750ft on 87 octane fuel. Looks good at first glance. Buuuuutttt.........
Exhaust thrust is crap. engine has much greater frontal area, Bristol cowlings suck (and the leading of the cowling is a major part of the exhaust system) and it weighs about 500lbs more than a Merlin III, granted it doesn't have 300 pounds or so of radiator and coolant.
The Vulture and Sabre will not arrive in time for the BoB. For the Sabre there are several things conspiring against it, a little more money won't solve the problems. They don't know how to mass produce the sleeve valves. At this point in time neither does Bristol, so they cannot be forced/compelled/coerced into sharing the secret with Napier as was done later.
Chances of pulling a rabbit out of hat like NA did with the Mustang is about zero. Mustang was one of the fastest aircraft projects in WW II even if you believe NA didn't have a bunch of preliminary drawings/calculations in hand (no designer worth his slide rule didn't have a least few napkin drawings/calculations for fighter even if he worked at Piper
Mustang took over two years to go from contract to 4 squadrons operating over Dieppe. You want 19 squadrons ready in Aug of 1940 you better have started in the summer of 1937 at the latest and more like 1936, which means 1936 air foils, 1936 flaps, 1936 radiators and so on, yes a few things can be changed but change too much and you don't meet the deadline.
Admiral Beez
Major
Perhaps we need to return to the Spitfire's origins. Were there any other British competitors in the Schneider races?
Shortround6
Major General
It was not a fishing expedition, It was a netting operation to capture what was on the hook already.
F.37/34 was written specifically for the Supermarine type 300 for contractual purposes just like F.36/34 was written specifically for the Hawker Hurricane. These were not "open" specifications for other manufacturers to respond to.
Shortround6
Major General
The Spitfire did NOT spring from the Schneider racers despite barrels of ink and tons of paper and millions of electrons saying so in poorly researched/thought out articles.
The type of construction was different, the air foils were different, about the only things the same were they were single engine planes using tractor propellers and having a single seat.
Some of the Schneider racers put the fuel in the floats because there wasn't room in the fuselage or in the wings. Hardly a good start for a land plane.
Just using internet sources Boulton and Paul was estimating the P.94 speed as 360mph with the Merlin XII (single stage single speed) and 364 with the Merlin XX (two speed engine)
I would suggest 10mph be knocked of for the armoured wind screen, IFF aerial and mirror that cost Spitfire Mk.II over 5mph compared to the Mk.I
So we have a 347-350 mph P.94 with a Merlin XII versus a 357mph Spitfire II with the same engine. That 7 mph represents 2.0% speed difference equal to the P.94 having 6% more drag.
Assuming the fuselages are equal it means the P.94 wing has 18% more drag. Spitfires more raked windscreen and better filleting has less drag but fully covered wheels make a big difference in favour of P.94 There is less wetted area in the P.94 fuselage as the thicker wing accommodates more equipment. The rear variable area ejector flap on the belly radiator can be seen. It seems to have improved and changed on Defiant II.
Note: the dorsal turret of the Lancaster cost it 12mph even when spread across 4 merlins, while a Lancaster is not Defiant it does give an indication of the serious impact of the big dorsal turret. That's a 4% cut in speed equal to about 12% cut in power ie worth 440hp across the 4 Merlins.
Below I will calculate an estimate of the power the Bouton and Paul Turret would absorb if its drag were added to a 360mph Spitifre II
The equations I will use are F=1/2.Cd.A.p.v^2 where F = drag force, p = air density, A = frontal area.
and Power = Force x Velocity. P=F.v where drag F = 0.5 x Cd.A.p.v^2 which gives:
P = 0.5 x Cd.A.p.v^3 (P = Power in kw, p = air density in kg/cubic m, which is 1.2kg/cubic meter at sea level or 0.6 at 20,000ft)
Lets calculate the Cd.A of the P.94 cockpit and its razorback. I estimate an windscreen area of 0.5m x 0.5m = 0.25sqm. I estimate an Cd of 0.15. (A perfect circular streamline is 0.05, a thin symmetrical wing 0.04, Fatman Nagasaki bomb teardrop about 0.15).
So Cd.A = 0.0375 (from 0.25 x 0.15)
Lets calculate the Cd.A of the Defiant Cockpit/Turret combo. I estimate an area of 0.75 x 0.6m = 0.40m. I estimate a Cd of 0.5. (A sphere is between 0.48 and 0.6, a half sphere flat face forward is about 0.5, a cylinder flat face forward is nearly 1) Its hard to get a Cd under 0.5 for a circular/spherical object because of suction on the back and turbulence. A sharp cut off is better. Note 0.6m width barely allows a human to fit between gun breeches. (assuming 75cm/28 inch turret ring)
So Cd.A = 0.20 (from 0.40 x 0.5)
The difference is about Cd.A of 0.1625.
If the Spitfire had the extra drag of the Defiant's turret at 360mph/160ms @ 20,000ft it would need 200kW = or about 250kW assuming 80% prop efficiency. That's 340hp, about 37% more than the 900 hp Merlin XII could provide at that altitude. Using a cube root law would produce a 13% speed reduction of the Spitfire i.e. 314mph.
Likewise the Defiant II at 315mph/ 140m/sec @ 20,000ft the removal of the turret reduces power demand by 134kW which is 167kW assuming 80% prop efficiency or 227hp so the aircraft can operate at 670hp instead of 900hp and that 227hp 33% increase in horsepower over 670mph would raise speed by 10% i.e. 346mph.
So the Boulton and Paul Estimates are Plausible.
My educated guess is that the P.94 with Merlin XII with 12 guns, IFF aerial, windscreen armour, mirror would be about 10-12 mph slower than a Spitfire III so 345-347 mph instead of 357.
It certainly wont be below 340mph, which is a lot fast than a Hurricane with the Merlin XX.
The p.94 aircraft would gracefully handle a Merlin 60, Griffon, Sabre or Vulture engine and would handle carrier operations (tough undercarriage, thick wing, good visibility) and could handle longer ranges if gun space were converted to fuel space.
Note If I use a Cd.A difference of 0.14 instead of 0.1625 the Spitfire drops to 325mph and the defiant increases to 343mph.
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wuzak
Captain
F.10/38?
wuzak
Captain
Gloster did in 1927 with the Gloster-Napier IV, and in 1929 with the Gloster-Napier VI, the latter as a reserve aircraft, not actually taking part in the race.
These were powered by the Napier Lion, as was the winning Supermarine S5 in 1927/ The Supermarine S6 of 1929 used the Rolls-Royce R.
Schneider Trophy race 1929 Gloster Napier VI
I have the test that this speed (I think) was gleaned from and there appears to be something wrong with this particular Defiant II's engine in 'S' ratio. The curve is all 'wrong' and very anemic. 'M' ratio looks very similar to a Hurricane IIb, just a tad slower, while in 'S' ratio the Defiant II looks like it's carrying 2x 500lb bombs or something ...
All things being equal the Defiant II should be about 8mph slower than a Hurricane II.
Admiral Beez
Major
To me it's amazing we believe in the absence of the Spitfire that a modified Defiant is the best Britain can do.
I got involved in this debate because I suggested that as Britain had advanced technology that in the absence of the Spitfire a specification would be issued that would produce a fighter as good as if not better,
I cited the Defiant as and example of excellent technology that if applied to a clean sheet fighter (rather than a turret fighter) would produce something as good if not better than Spitfire. Someone cited the P.94 and I saw it as proof of what could have been done if Boulton and Paul had of been told directly to develop an fighter.
To me the potential of Boulton & Paul was wasted.
Boulton and Paul P.103B naval fighter (Centaurus)I'm a big Whirlwind fan, but the Peregrine is as much a dead-end for Roll Royce as their Vulture, Eagle, Exe and Crecy. It's Merlins (and Meteors for the Army) all the way to VE Day.
I'd have pulled Petter off the Whirlwind and had him design the FAA's single engine, monoplane fighter instead of the Fairey Fulmar. Ideally a single seater if the FAA and AM can be strong armed to abandon the two seater notion. Essentially an early, smaller Merlin-powered version of Petter's Westland Wyvern.
Boulton and Paul P.103A naval fighter (Griffon)
It seems that the discussion has been turned from "no Spitfire" to "nothing anywhere near as good as the Spitfire ever". There were many efforts investigated to improve the Typhoon, Tempest, Fury with many different engine types and while they progressed they didn't do so very quickly, because they weren't really needed BECAUSE the Spitfire was there. To me the important development was the two stage Merlin which could just as easily have been a two stage Griffon, before that the Spitfire was a defensive fighter.
