Last & Best of the Piston Engine Fighter Aircraft.

[J.A.W.]

Very probably, M.o.A.P./Air Min R & D funding to R/R was contingent on certain undertakings made
by Hives, & case in point - the Eagle 22 - their Sabre clone, to provide a big power military engine.

A classic dual admission that the Vulture was never going to 'come good' (despite R/R claims)
& that R/R did have R & D people & space to spare, (if/when quids were up for grabs),
even if Hives knew the Eagle 22 was never going to replace either the Vulture, or Sabre,
he also knew that any funds he spent on 'his Sabre' wouldn't be going on the real one...

[Tommy Cookers]

the Merlin's cylinder bore was 5.4" and its cylinder spacing was 112.5% of that
the Griffon's cylinder bore was 6.0" and its cylinder spacing was 115% of that
the Sabre's cylinder bore was 5.0" and its average cylinder spacing was 140% of that

ie the Sabre was 23% longer relatively than were the conventional engines ....
(because it had wall ports not head ports - also partly because of the sleeve's thickness)

to maintain the crankshaft torsional and bending frequency (and crankcase stiffness) in a 23% relatively longer engine
(the crankshaft frequencies are vital to the fatigue life) ....
the crankshaft(s) must be 23% thicker & c.55% heavier and will give 51% more bearing friction
and the crankcase(s) must be 23% thicker and 51% heavier
this Sabre bearing over-capacity is confirmed as it allowed the elimination of crankshaft counterweighting
(and the H24 has further penalties from 2 crankshaft systems each less efficiently used than the conventional V12's)

so - there's better things than a water-cooled 4 stroke sleeve-valve aircraft engine ....
better make use the 23% length penalty of wall porting to have air-cooling - as did the Exe and the Pennine
or avoid the length penalty as a water-cooled H-24 with poppet valves would allow

the poor bearing capacities in the 20s dictated excessive engine length and so hid this downside of sleeve valves
when Ricardo's ideas formed this was normal and the future close-packed cylinders of WW2 would be inconceivable

non-engine aircraft weight etc will be increased by any increase of engine weight
the fighter aircraft (like the Grand Prix car) will suffer most in this respect

[J.A.W.]

T-C, from the 1st page of this thread it seems, you've evaded the ah, 'crux' of the matter, (& ignored
the most recent posts, likewise) since R/R engineers themselves had noted the Vulture was a dud..
(Per describing their 'Sabre clone' Eagle 22 in 'Flight', viz: 12 cylinders per crank was a def' limitation).

Even if (despite having a Sabre on hand for explicit reference) their 'Chinese copy' fell well short..

& also in 'Flight' not long previously (see link) R/R had also duly noted the limitations of their 'big' V12
Griffon (though carefully/painstakingly R & D worked over to remedy the issues arising in a decade's
worth of Merlin development), per boost/mechanical strength, esp' at low-levels, yet below power
levels/time limits which the robust Sabre had well-proven ability to capably take in its stride...

http://spitfireperformance.com/griffon-65.pdf

[Tommy Cookers]

T-C, from the 1st page of this thread it seems, you've evaded the ah, 'crux' of the matter, (& ignored the most recent posts, likewise) ....
http://spitfireperformance.com/griffon-65.pdf

evading the crux of the matter for 5 years ? .... no
but yes, I often don't respond to gainsaying (of things that I didn't say eg that the Vulture was good) ...

after 5 years we still have only Sabre 'smoke and mirrors' ....
a single figure (3500 hp takeoff 20 lb boost) in a 1947 amateur-interest book ... with ZERO corroboration or context
this has NOTHING to do with the Tempest
the late 1945 Flight article has S VII on ADI Tempest 3000 hp t/o 17.25 lb boost and 3055hp @MSFTH 2250' 17.25lb
Closterman's unit 'had a few' - he collected his in Mar 1945
it seems Sabre ADI existed before this - do we even know if Closterman used this 3055 or some earlier/lesser version ?
do records exist to support this in wider use ? - the (often knowledgeable) simulator fans seem quiet about it
there's unit records of ammunition load and use but nothing on emergency boost ?

comparing almost all of the Sabres made with many of the conventional engines (then) made .....
the sleeve-valve engines power:weight ratio was c.10% worse than those conventional engines
this is the crux of the matter (of the Sabre Tempest wrt conventional fighters) ....
a fighter being a machine whose weight is almost proportionate to the engine's weight .....
the Tempest wouldn't be better than a conventionally-powered plane designed for the same altitude & wing loading

3055 hp from 2540 lb is 0.38 of your kg/hp (conveniently ignoring the ADI weight both dumped and burned)
no better power:weight ratio than an Allison or a single-speed Merlin without ADI (or late DB605 with ADI)
the (2 stage non-turbo) Allisons in the Korean war F-82s gave (on 115/145 100" & ADI) 2250 hp for 1595 lb
this is 0.32 kg/hp ..... (ie better even than the notional (or mythical) 3500 hp Sabre)
ADI makes a mockery of the 'Sabre is efficient' arguments
45% of the burn (in high supercharge) is methanol - the ADI massflow is c. 3 times the fuel massflow replaced by ADI

the technical anti-Sabre argument was largely that its weight was disproportionately high (due to its lavish porting)
the technical pro-Sabre argument was largely that supercharger power was disproportionately lower (due to lavish porting)

ie at some height and power the Sabre could need only single stage supercharging vs a conventional engine's 2 stage
but the 'Sabre crybabies' still cry over officialdom's denial of Sabre '2 stage Sabre rights'
since 2 speed 2 stage Merlins were c.200 lb heavier than 2 speed single-stage ones ....
we should expect a 2 stage Sabre to have been 350 lb heavier than the 2540 lb Sabre VII ie 2900 lb .... so ....
the RR Eagle 22 weight of 3900 lb was proportionate to its size and 2 stage design
(ok 2 stage 2 speed Griffons had superchargers series-connected ie fixed relative ratio so lighter - but 3 speeders ?)

the Griffon 65 article tells us some surprising things .....
EVO is 64 deg BBDC - later even than the Sabre's
'lean' mixture isn't truly lean but c. stoichiometric (though 100/130 etc stoi is c.14 not the expected 14.7 for gasoline)
rather high minimum power .... this simplicity a sign of the times ....
the maximum power taken by the supercharging is 600 hp ..... but ....
doesn't c. 300 hp of that return to the crankshaft by the 'air motor' effect of the piston engine ?

[J.A.W.]

T-C, from the 1st page of this thread it seems, you've evaded the ah, 'crux' of the matter, (& ignored the most recent posts, likewise) ....
http://spitfireperformance.com/griffon-65.pdf

evading the crux of the matter for 5 years ? .... no
but yes, I often don't respond to gainsaying (of things that I didn't say eg that the Vulture was good) ...

after 5 years we still have only Sabre 'smoke and mirrors' ....
a single figure (3500 hp takeoff 20 lb boost) in a 1947 amateur-interest book ... with ZERO corroboration or context
this has NOTHING to do with the Tempest
the late 1945 Flight article has S VII on ADI Tempest 3000 hp t/o 17.25 lb boost and 3055hp @MSFTH 2250' 17.25lb
it seems Sabre ADI existed before this - do we even know if Closterman used this 3055 or some earlier/lesser version ?
do records exist to support this ? - the (often knowledgeable) simulator fans seem quiet about it
there's unit records of ammunition load and use but nothing on emergency boost ?

comparing almost all of the Sabres made with many of the conventional engines (then) made .....
the sleeve-valve engines power:weight ratio was c.10% worse than those conventional engines
this is the crux of the matter (of the Sabre Tempest wrt conventional fighters) ....
a fighter being a machine whose weight is almost proportionate to the engine's weight .....
the Tempest wouldn't be better than a conventionally-powered plane designed for the same altitude & wing loading

3055 hp from 2540 lb is 0.38 of your kg/hp (conveniently ignoring the ADI weight both dumped and burned)
no better power:weight ratio than an Allison or a single-speed Merlin without ADI (or late DB605 with ADI)
the (2 stage non-turbo) Allisons in the Korean war F-82s gave (on 115/145 100" & ADI) 2250 hp for 1595 lb
this is 0.32 kg/hp ..... (ie better even than the notional (or mythical) 3500 hp Sabre)
ADI makes a mockery of the 'Sabre is efficient' arguments
45% of the burn (in high supercharge) is methanol - the ADI massflow is c. 3 times the fuel massflow replaced by ADI

the technical anti-Sabre argument was largely that its weight was disproportionately high (due to its lavish porting)
the technical pro-Sabre argument was largely that supercharger power was disproportionately lower (due to lavish porting)

ie at some height and power the Sabre could need only single stage supercharging vs a conventional engine's 2 stage
but the 'Sabre crybabies' still cry over officialdom's denial of Sabre '2 stage Sabre rights'
since 2 speed 2 stage Merlins were c.200 lb heavier than 2 speed single-stage ones ....
we should expect a 2 stage Sabre to have been 350 lb heavier than the 2540 lb Sabre VII ie 2900 lb .... so ....
the RR Eagle 22 weight of 3900 lb was proportionate to its size and 2 stage design
(ok 2 stage 2 speed Griffons had superchargers series-connected ie fixed relative ratio so lighter - but 3 speeders ?)

the Griffon 65 article tells us some surprising things .....
EVO is 64 deg BBDC - later even than the Sabre's
'lean' mixture isn't truly lean but c. stoichiometric (though 100/130 etc stoi is c.14 not the expected 14.7 for gasoline)
rather high minimum power .... this simplicity a sign of the times ....
the maximum power taken by the supercharging is 600 hp ..... but ....
doesn't c. 300 hp of that return to the crankshaft by the 'air motor' effect of the piston engine ?

Well, that's another rather emotively obfuscational blast T-C...

To describe the official ratings figures listed in Wilkinson's technical tome as: "an amateur interest book"!
& to dismiss Bill Pearce's cogent well-researched article as mere: "smoke and mirrors... sabre crybabies"!

See it again? https://oldmachinepress.com/2020/09/20/ ... ft-engine/

Do note how compactly the Sabre fits even the 'lightweight' Hawker Fury shown with cowling down:



The crux being T-C, that you continue to ignore the fact that the R/R V12s you cite could not sustain
the high power levels of the Sabre, which even in 'dry' form used by the service Tempest F6 was capable
of a max continuous cruise hp (as previously noted) which the most highly developed Merlins - could only
manage for ephemeral periods - at max boost on super hi-grade avgas...

Wingco Beamont likewise wrote of utilizing this capability in wartime armed recce ops...

If you read up on the Allison-powered P/F-82 Twin Mustangs, you'll find they were seldom capable
of making 'book figures' in service, & were a disappointment to pilots who'd initially trained on the
Merlin-powered early production units, kept for this purpose.

[wuzak]

The crux being T-C, that you continue to ignore the fact that the R/R V12s you cite could not sustain
the high power levels of the Sabre, which even in 'dry' form used by the service Tempest F6 was capable
of a max continuous cruise hp (as previously noted) which the most highly developed Merlins - could only
manage for ephemeral periods - at max boost on super hi-grade avgas...

The Merlin was a smaller engine, with much less frontal area and less weight. It didn't need as much power to propel aircraft designed around it as the aircraft designed around the Sabre did. (That said, the Fury and Tempest were compromised in this regard by also having to accommodate the Centaurus.)

The Griffon was, similarly small and lighter than the Sabre. One of the features of the Griffon was that it was small enough to fit in a Spitfire.

As to cruise power, the Spitfire XI could cruise at 390mph @ 40,000ft and the Spitfire XIX could cruise at 400mph @ 40,000ft.

The Tempest F.6 was very much a post war aircraft.

Would have been interesting to see what the RM.17SM would have done in service, being rated at 2,200hp MS/2,100hp FS and flight rated at ~2,350hp. That is not far behind the Sabre in late 1944.

If you read up on the Allison-powered P/F-82 Twin Mustangs, you'll find they were seldom capable
of making 'book figures' in service, & were a disappointment to pilots who'd initially trained on the
Merlin-powered early production units, kept for this purpose.

The V-1650-9 with ADI had similar performance to the V-1710s in the P-82, but with 90inHg MAP vs the 100inHg MAP.

The RM.17SM could match those without ADI.


After all these years you still haven't figured out that the forum automatically wraps text?

[J.A.W.]

The crux being T-C, that you continue to ignore the fact that the R/R V12s you cite could not sustain
the high power levels of the Sabre, which even in 'dry' form used by the service Tempest F6 was capable
of a max continuous cruise hp (as previously noted) which the most highly developed Merlins - could only
manage for ephemeral periods - at max boost on super hi-grade avgas...

The Merlin was a smaller engine, with much less frontal area and less weight. It didn't need as much power to propel aircraft designed around it as the aircraft designed around the Sabre did. (That said, the Fury and Tempest were compromised in this regard by also having to accommodate the Centaurus.)

The Griffon was, similarly small and lighter than the Sabre. One of the features of the Griffon was that it was small enough to fit in a Spitfire.

As to cruise power, the Spitfire XI could cruise at 390mph @ 40,000ft and the Spitfire XIX could cruise at 400mph @ 40,000ft.

The Tempest F.6 was very much a post war aircraft.

Would have been interesting to see what the RM.17SM would have done in service, being rated at 2,200hp MS/2,100hp FS and flight rated at ~2,350hp. That is not far behind the Sabre in late 1944.

If you read up on the Allison-powered P/F-82 Twin Mustangs, you'll find they were seldom capable
of making 'book figures' in service, & were a disappointment to pilots who'd initially trained on the
Merlin-powered early production units, kept for this purpose.

The V-1650-9 with ADI had similar performance to the V-1710s in the P-82, but with 90inHg MAP vs the 100inHg MAP.

The RM.17SM could match those without ADI.


After all these years you still haven't figured out that the forum automatically wraps text?

"After all these years..." it seems you still miss the salient 'fact-in-your-face' wuzak, being the
very limited time periods that Spitfire - R/R V12s could operate at those power levels, being
such as which the Sabre could maintain for as long as the fuel lasted... let alone never come
close in actual combat results, in terms of VNE/Vmax or in quantifiable effectiveness in
RAF fighter/fighter-bomber use, by both ADGB/2nd TAF, in 1944/45.

Just compare Tempest V & Spitfire XIV victory credits, or for a closer comparison, compare the
2 Kiwi fighter squadrons kept in Blighty with the RAF, 485 & 486; 485 started 1st, & flew Spits
exclusively, while 486 started later, on Hurricanes, through Typhoons to Tempests, no guesses
as to which unit proved more effective - in combat results - are needed...

As for high altitude performance, you do realize the Tempest offered superior VNE numbers
'upstairs' as well, but the "more warlike" Hawker fighter was wanted for low-level tactical use,
so was not developed for 'swanning about the stratosphere' (& no Spitfire matched the ~470mph
achieved by the Tempest I on test in 1943, at ~25,000ft height).

[wuzak]

"After all these years..." it seems you still miss the salient 'fact-in-your-face' wuzak, being the
very limited time periods that Spitfire - R/R V12s could operate at those power levels, being
such as which the Sabre could maintain for as long as the fuel lasted... let alone never come
close in actual combat results, in terms of VNE/Vmax or in quantifiable effectiveness in
RAF fighter/fighter-bomber use, by both ADGB/2nd TAF, in 1944/45.

I said they were cruise speeds. The XI and XIX were PR aircraft, and they would cruise at ~400mph @ 40,000ft with less than 1,000hp.

[J.A.W.]

"After all these years..." it seems you still miss the salient 'fact-in-your-face' wuzak, being the
very limited time periods that Spitfire - R/R V12s could operate at those power levels, being
such as which the Sabre could maintain for as long as the fuel lasted... let alone never come
close in actual combat results, in terms of VNE/Vmax or in quantifiable effectiveness in
RAF fighter/fighter-bomber use, by both ADGB/2nd TAF, in 1944/45.

I said they were cruise speeds. The XI and XIX were PR aircraft, and they would cruise at ~400mph @ 40,000ft with less than 1,000hp.

Yes, of course the thin air at such altitudes allows for such things, as long as the engine compressor
is also designed to deliver the required quantum to maintain power, but these were not fighters*,
nor was that cruise speed available at altitudes useful for armed recce, (Allison P-51 was preferred)
& the pressurised cockpit fighter Spitfires actually saw very little combat use.

*AFAIK, 'laying on an intercept' of such speedy high-level PR flights was virtually impossible until
the advent of 2nd gen swept-wing jet interceptors, years later.

[Tommy Cookers]

Well, that's another rather emotively obfuscational blast T-C...
To describe the official ratings figures listed in Wilkinson's technical tome as: "an amateur interest book"!
& to dismiss Bill Pearce's cogent well-researched article as mere: "smoke and mirrors... sabre crybabies"!
See it again? https://oldmachinepress.com/2020/09/20/ ... ft-engine/
Do note how compactly the Sabre fits even the 'lightweight' Hawker Fury shown with cowling down:
The crux being T-C, that you continue to ignore the fact that the R/R V12s you cite could not sustain ....
.. could only manage for ephemeral periods - at max boost on super hi-grade avgas...
Wingco Beamont likewise wrote of utilizing this capability in wartime armed recce ops...

don't hold back JAW ! and please feel free to relocate the crux whenever it suits you !

Beamont was on the weakest ground in advocating the Sabre use in reconnaisance
but working for Hawker on secondment he exempted himself from the obligations of service test pilots
the Fury was a big heavy plane because it had a big heavy engine
though the bigger heavier Tempest is the crux of this thread


yet again .... I have always said that .....

3055 hp@2250' FTH on 17.25lb boost with ADI was available in some Tempest combat use in WW2 eg Closterman etc
(though there's no evidence that some previous level of ADI/boost wasn't what C wrote of using ??)

3500 hp t/o on 20lb with ADI didn't exist in WW2 or in any Tempest ever
(Pearce doesn't say that it did - his ADI figures as the (Sep 45 ?) Flight article are for 17.25 lb)

there is no data or eg Flight article supporting the 3500hp/20lb - and 3500hp doesn't appear anywhere till 1947
(a reasonable person would guess this rating was to attract postwar bomber or airliner designers)

so ....
3500 hp is cherry-picking ie illegitimate for the Tempest's claim on this thread's title .... and similarly ....
reverse cherry-picking is illegitimate (ie discounting other engines use of better avgas than the Sabre used) ...and ...
similarly it's tosh to say that Merlin ratings were ephemeral ...
but act as if Sabre takeoff ratings or ADI ratings were non-ephemeral

btw
the Spiteful (150 ordered) was by Jan 1945 officially tested at 494 mph @ 28500' and 4900 fpm climb
2420 hp Griffon 101 (3 speed) - 9950 lb gross weight and 210 sq ft wing area
12x3" or 4x300lb rocket-capable or 2x1000lb bomb-capable (same as Tempest or Sea Fury)
T6 max permissible t/o wt 14450 lb 302 sq ft & SF 11 max wt 14650 lb and 280 sq ft
(ok gross wt and max wt maybe not same thing)
(remember 1500 Spitfire IIIs were to be 220 sq ft - but their engines were witheld to benefit Hurricanes)
the Spiteful was good enough to go into production if needed - it just wasn't needed
(let's not have anyone telling me that eg bears defaecate in the woods)
as postwar Tempests didn't ever have 3000 hp ADI ? - because it just wasn't needed

btw 2
the Army-Cooperation 'Rhubarb' fighter sweeps in 1943 used single-stage Allison-engined Mustangs ....
supplied for 60" 1570 hp but reset to 70" and 1780 hp
and they wave-hopped using 1100 rpm
engine weight c.1350 lb

btw 3
in 1938 the 'sprint Merlin' for the Speed Spitfire gave over 2100 hp @ 28 lb boost - on gasoline with 20% methanol
(ie less methanol % than typical of the ADI use later)
and 1800 hp for 15 hr continuously
engine weight c.1350 lb

[J.A.W.]

Well, that's another rather emotively obfuscational blast T-C...
To describe the official ratings figures listed in Wilkinson's technical tome as: "an amateur interest book"!
& to dismiss Bill Pearce's cogent well-researched article as mere: "smoke and mirrors... sabre crybabies"!
See it again? https://oldmachinepress.com/2020/09/20/ ... ft-engine/
Do note how compactly the Sabre fits even the 'lightweight' Hawker Fury shown with cowling down:
The crux being T-C, that you continue to ignore the fact that the R/R V12s you cite could not sustain
the high power levels of the Sabre, which even in 'dry' form used by the service Tempest F6 was capable
of a max continuous cruise hp (as previously noted) which the most highly developed Merlins - could only
manage for ephemeral periods - at max boost on super hi-grade avgas...
Wingco Beamont likewise wrote of utilizing this capability in wartime armed recce ops...

don't hold back JAW !
and please feel free to relocate the crux whenever it suits you !
(or is it the technical bit of technical.net that you can't accept ?)

yet again .... I have always said that .....

3055 hp@2250' FTH on 17.25lb boost with ADI was available in some Tempest combat use in WW2 eg Closterman etc
(though there's no evidence that this level of boost existed in WW2 service ??)

3500 hp t/o on 20lb with ADI didn't exist in WW2 or in any Tempest ever
(Pearce doesn't say that it did - his ADI figures as the (Sep 45 ?) Flight article are for 17.25 lb)

there is no data or eg Flight article supporting the 3500hp/20lb - and 3500hp doesn't appear anywhere till 1947
(a reasonable person would guess this rating was to attract postwar bomber or airliner designers)

so ....
3500 hp is cherry-picking ie illegitimate for the Tempest's claim on this thread's title .... and similarly ....
reverse cherry-picking is illegitimate (ie discounting other engines use of better avgas than the Sabre used) ...and ...
similarly it's tosh to say that Merlin ratings were ephemeral ...
but act as if Sabre takeoff ratings or ADI ratings were non-ephemeral

btw
the Spiteful (150 ordered) was by Jan 1945 officially tested at 494 mph @ 28500' and 4900 fpm climb
2420 hp Griffon 101 (3 speed) - 9950 lb gross weight and 210 sq ft wing area
12x3" or 4x300lb rocket-capable and 2x1000lb bomb-capable (same as Tempest or Sea Fury)
(Tempest 6 max weight 13700 lb 302 sq ft - Sea Fury 11 max weight 14650 lb and 280 sq ft)
(remember 1500 Spitfire IIIs were to be 220 sq ft - but their engines were held back to benefit Hurricanes)
the Spiteful was good enough to go into production if needed - it just wasn't needed
(let's not have anyone telling me that eg bears defaecate in the woods)
postwar Tempests didn't ever have 3000 hp ADI - because it just wasn't needed

btw 2
the Army-Cooperation 'Rhubarb' fighter sweeps in 1943 used single-stage Allison-engined Mustangs ....
supplied for 60" 1570 hp but reset to 70" and 1780 hp
and they wave-hopped using 1100 rpm
engine weight c.1350 lb

btw 3
in 1938 the 'sprint Merlin' for the Speed Spitfire gave over 2100 hp @ 28 lb boost - on gasoline with 20% methanol
(ie less methanol % than typical of the ADI use later)
and 1800 hp for 15 hr continuously
engine weight c.1350 lb

Oh dear T-C, some big claims there... (seems you've as yet failed - to read the linked Bill Pearce piece?).

The 'Speed Spitfire' venture was abandoned due to it being deemed unable to beat the 'Rekord He 100',
& because the Sabre-powered Nuffield Heston racer was pending... furthermore that Sabre went on
to see wartime service in a Typhoon, which that 'hot-rodded' Merlin was quite incapable of doing...

Where is your evidence of the Spiteful's high-speed/high altitude test on a 130 series Griffon, being
deemed "official", rather than a stunt, since it prematurely ended in engine failure/crash-landing?

Why do I have to repeat ad infinitum, that the Sabre's 'climb' power was unrestricted, but for fuel
capacity, as was 'normal' power, yet it took max-boost on hi-test juice - for a matter of mere minutes
by the Merlin to approach these outputs - before having to back off, let alone going near to matching
the 'combat' rating of the contemporary Sabre, or hacking max-boost at low-level, likewise...


The Spiteful of course never made service, & its naval iteration was likewise overlooked by the
FAA in favour of the Sea Fury. Tropicalised Tempest F.2/F.6 squadrons were far more numerous
than any postwar Spitfire marks, due to the RAF wanting piston-engine powered fighter-bombers,
but no new high altitude interceptor types, unless they were turbo-jets...

& you surely realize that even the highest performing Griffon-powered fighter was bested by its
contemporary Sabre-powered Hawker, at the altitude band (S.L. - 20,000ft) required by the RAF,
from 1943-45 & postwar by its piston engine fighters, & that it took the 20 Series Spits - virtually
too late for WW2 service - to match the Typhoon's 1941 VNE, in service power output & 4 X 20mm fit!

Additionally, Wingco Beamont certainly flew the Sabre Hawkers in combat, including returning to ops
for D-day/V1 defence/post-invasion duties.

Napier ran a flight-test section at Luton, where experimental Sabre-powered Hawker fighters were
'on hand' for such things as turbo-charger/annular-radiator/ADI installations for ongoing evaluation,
so its very likely, they'd proof-fly the +20lb boost Sabre VII in their Tempest F.6, prior to sending any
to the Hawker works at Langley (to then fly in the 2nd Sabre-Fury prototype) as shown in this page..

[wuzak]

The 'Speed Spitfire' venture was abandoned due to it being deemed unable to beat the 'Rekord He 100',
& because the Sabre-powered Nuffield Heston racer was pending... furthermore that Sabre went on
to see wartime service in a Typhoon, which that 'hot-rodded' Merlin was quite incapable of doing...

The Speed Spitfire was a modified production Spitfire.

The Napier-Heston Racer was a custom prototype designed specifically to get the record.

The Napier-Heston racer flew only once, only for a few minutes, the hand-built prototype engine overheated and was put into a production Typhoon, but only after a rebuild and setting the boost back to normal parameters.

I'm sure the "hot rodded" Merlin could also have been returned to normal specs and put back into service.

Where is your evidence of the Spiteful's high-speed/high altitude test on a 130 series Griffon, being
deemed "official", rather than a stunt, since it prematurely ended in engine failure/crash-landing?

Did it?

We do know that the Hornet I with two Merlins could do 470mph+ and the P-51H with Merlin 100-series (V-1650-9) was capable of 480mph+.

Why do I have to repeat ad infinitum, that the Sabre's 'climb' power was unrestricted, but for fuel
capacity, as was 'normal' power, yet it took max-boost on hi-test juice - for a matter of mere minutes
by the Merlin to approach these outputs - before having to back off, let alone going near to matching
the 'combat' rating of the contemporary Sabre, or hacking max-boost at low-level, likewise...

The Merlin did not need the same sort of power to exceed the climb of a Tempest because it was fitted to a much lighter aircraft.

The Spiteful of course never made service, & its naval iteration was likewise overlooked by the
FAA in favour of the Sea Fury. Tropicalised Tempest F.2/F.6 squadrons were far more numerous
than any postwar Spitfire marks, due to the RAF wanting piston-engine powered fighter-bombers,
but no new high altitude interceptor types, unless they were turbo-jets...

The Sea Fury also overlooked the Sabre variant.

Could you provide a list of Spitfire and Tempest squadrons post war?

The Spiteful was, indeed, killed by the desire of the RAF for jet fighters, but also because they had quite a lot of Spitfires - XIV, XVIII, XIX, 21, 22 and 24, plus VIIIs and IXs.

& you surely realize that even the highest performing Griffon-powered fighter was bested by its
contemporary Sabre-powered Hawker, at the altitude band (S.L. - 20,000ft) required by the RAF,
from 1943-45 & postwar by its piston engine fighters, & that it took the 20 Series Spits - virtually
too late for WW2 service - to match the Typhoon's 1941 VNE, in service power output & 4 X 20mm fit!

The Spitfire 21 saw service from January 1945.

From where do you get the idea that the RAF only wanted piston fighters for the altitude band 0-20,000ft?

Twice as many Spitfire 22s were produced as there were Tempest VIs.

There were a few Mk Vs fitted with 4 x 20mm cannon, and the wings of later models could fit them, if so desired.

Napier ran a flight-test section at Luton, where experimental Sabre-powered Hawker fighters were
'on hand' for such things as turbo-charger/annular-radiator/ADI installations for ongoing evaluation,
so its very likely, they'd proof-fly the +20lb boost Sabre VII in their Tempest F.6, prior to sending any
to the Hawker works at Langley (to then fly in the 2nd Sabre-Fury prototype) as shown in this page..

The Tempest VI was a post war aircraft.

How many Sabre VIIs were built?

[J.A.W.]

The title of this thread is self evident, it does not confine the aircraft under consideration to WW II
usage/operational service - although as matter of interest, while the 'Speed Spitfire' was modified
beyond reasonably practicable reuse as a fighter - it did get a gig in an early PR Unit.

Wuzak, you say you are "sure" the 'R' spec Merlin used "could have been returned to normal..."
& used in a regular service aircraft, do you base this idea upon any supportive evidence?
Seems more reasonable - the modifications/strains imposed - would've precluded this, IMO.

Likewise, while the RAF had all 3 Tempest combat Mks (II/V/VI) already listed 'on strength',
during WW II, (with twice as many Mk II/VI ultimately built as Spitfire Mk 22/24 , only the Mk V
saw combat unit ops during wartime, (& the Spitfire Mk 21, which lacked the larger tail empennage
designed for the Spiteful, was quickly withdrawn from service & then scrapped, post-war).

My comment "post war" was related to final marks of Spitfire/Spiteful (& Seafire/Seafang),
as noted, not the thousands of Merlin/Griffon types already kept on hand in RAF stocks.
(Nor did the earlier Spitfire marks prove satisfactory with a RAF standard 4 X 20mm cannon fit).

The longer range/'loiter time' of piston-engine fighter-bombers was seen as the reason
why the RAF still wanted lower altitude-band performance from them, whereas turbo-jets
were to take on the high-altitude tasks.

See here: http://www.wwiiaircraftperformance.org/ ... Flight.pdf


Of course, political/industrial considerations entered into things - with Bristol's Centaurus
requiring post-war production contracts, (inc' for the Sea Fury, even though the Fury was flown
with the Griffon, which was already in FAA use, & the FAA specific Sabre III had likewise been
developed & produced in small numbers for the Blackburn Firebrand) to ensure the much larger
Bristol works was kept viable (regardless of another complication for naval flying) - whereas
E.E./Napier's relatively modest 'wartime production shadow factory' could simply be shut.

Presumably, the low-time Sabre engines pulled from Typhoons withdrawn from service & scrapped
post-war were refurbished in moderate numbers for Tempest use through to the mid 1950's...

I don't have production numbers for the Sabre VII, but it appears that they make up a fairly high %
of still extant Sabre engines on display in museums & in private ownership, even if most have been
'sectioned' & rendered incapable of running again.

[Tommy Cookers]

Oh dear T-C, some big claims there... (seems you've as yet failed - to read the linked Bill Pearce piece?).

Napier ran a flight-test section at Luton, where experimental Sabre-powered Hawker fighters were
'on hand' for such things as turbo-charger/annular-radiator/ADI installations for ongoing evaluation,
so its very likely, they'd proof-fly the +20lb boost Sabre VII in their Tempest F.6, prior to sending any
to the Hawker works at Langley (to then fly in the 2nd Sabre-Fury prototype) as shown in this page..

spare me the condescension !
it's not me that can't read !

the Pearce piece says that ....
the Tempest VI (142 made) was powered by the Sabre VA - airframe manufacture starting in 1946 and finishing in 1947
the Sabre VII was the engine for the Fury - but the Fury never entered service
the Sabre VII was 'later' rated on 20 lb boost with ADI at 3500 hp ....
('later' others have said is eg the 1951 Aero Engines of the World)

so ....
no production Tempest ever had 3500 hp - or more than 3055 hp
(and no-one believes otherwise - because no-one has found any evidence)


and there's no evidence that any Tempest prototype did have ....
the 25th July 1946 Flight article says the tailless Napier concept 'was to have the 3350 hp E122' and ....
'for the time the VA and the VII ... are the latest production units' - (page 99 for these)

Flight also has 3.10.1946 'spinning intake' and 7.10.1948 'annular Tempest 6'
in 1947 the Engines Production Ministry sent the E122 etc and its developers to RR

[J.A.W.]

spare me the condescension !
it's not me that can't read !

the Pearce piece says that ....
the Tempest VI (142 made) was powered by the Sabre VA - airframe manufacture starting in 1946 and finishing in 1947
the Sabre VII was the engine for the Fury - but the Fury never entered service
the Sabre VII was 'later' rated on 20 lb boost with ADI at 3500 hp ....
('later' others have said is eg the 1951 Aero Engines of the World)

so ....
no production Tempest ever had 3500 hp - or more than 3055 hp
(and no-one believes otherwise - because no-one has found any evidence)


and there's no evidence that any Tempest prototype did have ....
the 25th July 1946 Flight article says the tailless Napier concept 'was to have the 3350 hp E122' and ....
'for the time the VA and the VII ... are the latest production units' - (page 99 for these)

Flight also has 3.10.1946 'spinning intake' and 7.10.1948 'annular Tempest 6'
in 1947 the Engines Production Ministry sent the E122 etc and its developers to RR

C'mon now T-C, "no one" having anywhere near a fair knowledge of such technical-interest things
could - on the 'balance of probabilities' - reasonably doubt (per those 'Flight' articles*) that both
Napier-Luton & Hawker-Langley would've duly flown the 'last & best' (& M.A.P. type-test cleared)
iteration of the Sabre VII on test in their Tempest 6 & Sabre Fury respectively, including in its
+20lb boost final production form. Sabre Fury VP 207 was still on flight-test at Langley in 1948.

The Tempest F.6 was the final Tempest mark produced by Hawkers, & incorporated various airframe
improvements airframe developed via the F.2, & by use of the latest Sabre V, with an available
+15lb boost on usual 100/130 avgas - for normal postwar/peacetime use - sans the addition of ADI.


*Link to the IMechE site, "...home to the Napier Archive": https://archives.imeche.org/archive/eng ... napier-son?