Hawker Typhoon and Tempest with RR Griffon

BarnOwlLover

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One, what would it have looked like/been like, and second, would it have been more successful than the Sabre powered variants?
 

EwenS

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Tempest Mk.III planned with single stage Griffon IIB
Tempest Mk.IV planned with two stage Griffon 61.

A single Tempest MK.III prototype, LA610, was flown but with a Griffon 85. See below.

1670066494226.jpeg



LA610 was later refitted with a Sabre VIII as a prototype Fury
1670066702336.jpeg
 

wuzak

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Given that the Typhoon was designed around the physically larger Sabre, and the Tempest was designed to use the Sabre and Centaurus, the airframe was probably too large for the Griffon.

The Griffon didn't have the power of the other engines, but its advantages wee lost when fitted in the big airframe.

A smaller fuselage mated to the Tempest wings may have been a decent performer.
 

tomo pauk

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Given that the Typhoon was designed around the physically larger Sabre, and the Tempest was designed to use the Sabre and Centaurus, the airframe was probably too large for the Griffon.

The Griffon didn't have the power of the other engines, but its advantages wee lost when fitted in the big airframe.

Being smaller and lighter will make the installation easier.
A 2-stage Griffon was making better power above 15000 ft than the Sabre.

A smaller fuselage mated to the Tempest wings may have been a decent performer.

How about the Fury's airframe + 2-stage Griffon. Fury was with the smaller wing vs. the Tempest.
 

EwenS

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From Tony Buttler’s book on the Tempest.

Griffon engined Tempest began as Hawker P.1016 proposal in early 1942. The conversion would have been easy as lighter Griffon was longer so the balance of the aircraft was practically unchanged. RR had agreed to provide the engine as a “power egg” to bolt onto the fuselage. The Griffon IIB option was quickly discarded.

It was thought that the Griffon Tempest could not enter production until mid1943 at a point when large numbers of Typhoons were being produced, and the latter was considered the first step in conversion from the Hurricane for ground attack duties, with Griffon Tempest being a follow on to Typhoon. As things turned out there was no need for a ground attack Typhoon successor in WW2.

So the one Griffon Tempest prototype LA610 became part of the Fury development line, first flying in Nov 1944.
 

Howard Gibson

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My understanding is that the RAF used Spitfires for operations over 20,000ft, and some Hawker product for operations below 20,000ft. Particularly in the case of Spitfires, this distinction became very fuzzy.

In his book Calum Douglas regrets that Napier and Bristol failed to develop sophisticated superchargers for their iconic engines, wasting engineering resources on sleeve valves. I am not sure the RAF cared. If they wanted something bad to happen to you at 35,000ft, they sent Spitfires. Would a Griffon engined Tempest have been better than a Griffon engined Spitfire?
 

EwenS

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To use the Griffon, any Griffon let alone the Griffon 61 series, in the Tempest from mid-late 1943 would have required a massive increase in production at RR. Consider Spitfire XIV/XVIII/XIX production totalled <1500 aircraft 1943-45. The lower powered Griffon IIB was only in Firefly (c800) & Spitfire XII (100), Seafire XV/XVII (c400) by Sept 1945.
 

tomo pauk

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My understanding is that the RAF used Spitfires for operations over 20,000ft, and some Hawker product for operations below 20,000ft. Particularly in the case of Spitfires, this distinction became very fuzzy.

If a fighter is well suited for an altitude band, prudent thing will be to use it in that altitude band. Sabres on Typhoons and Tempests dictated the lower altitudes than it was the case with Spitfires outfitted with 2-stage supercharges. IOW - Hawker's heavies 1st shown that they are better suited for lower altitudes, making RAF use them there as a consequence.
But indeed, there was a host of Spitfire marks better suited for lower altitudes, again powered by engines that have had superchargers better suited for these altitudes. We can note that impeller of the supercharger on the Griffon II was of smaller diameter than what Merlin III used; small impeller -> low altitudes.

In his book Calum Douglas regrets that Napier and Bristol failed to develop sophisticated superchargers for their iconic engines, wasting engineering resources on sleeve valves. I am not sure the RAF cared. If they wanted something bad to happen to you at 35,000ft, they sent Spitfires. Would a Griffon engined Tempest have been better than a Griffon engined Spitfire?

Bingo on the wasting resources on sleeve valve engines instead on superchargers.
A Griffon-engined Tempest (2-stage Griffon, since the 1-stage version will not be worth it IMO) should offer better rate of roll, better weapon set-up, and possibly greater CoG-neutral fuel tankage. Leading-edge radiators should be better than what the Spitfires had, however the LE fuel tanks need to be supplanted by tank(s) in fuselage in that case. Tempest's drop tanks seem like a more elegant solution than what Spit XIV used.
The Fury/Sea Fury has a smaller wing than the Tempest, for lower drag and weight, but it is also too late for ww2.
 

Shortround6

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One, what would it have looked like/been like, and second, would it have been more successful than the Sabre powered variants?
When???
The Typhoon first flew with the Sabre engine in Feb 1940 and went into operational service in Sept-Oct 1941.

What Griffon engine was available in in that time line (prototypes under construction in 1939/early 40) and at what power level, actual or promised.
Designing a plane that uses a 1700hp engine for take off is quite a bit different than using an engine that promises 2200hp.
 

BarnOwlLover

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How about this, also includes a sketch of the Tempest III (designed, but never built) and a speculative model of the Tempest IV (never built, I don't know how far it got in design):


This also touches on how the registration/serial number LA610 was reassigned from the Tempest III to the Fury I when powered both by the Griffon 85 and Sabre VII.

In short, though, the Tempest III (based on the concept illustration) looked much the same as the Tempest V but with a slimmer radiator housing and small bulges in the upper cowling to clear the Griffon's valve covers. The Tempest IV is thought to maybe be similar to the II but with a longer nose due to the two stage supercharger (III was intended to use the Griffon IIB, the Tempest IV was planned to use the Griffon 65), or possibly using a quasi-annuar radiator that the Fury I (Griffon) or Avro Lincoln and Shackleton used.

Expected performance with the Griffon II was expected to be in he ball park of the Typhoon, while the Griffon 65 was though to be roughly the same as the Tempest V.
 

tomo pauk

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What Griffon engine was available in in that time line (prototypes under construction in 1939/early 40) and at what power level, actual or promised.
Designing a plane that uses a 1700hp engine for take off is quite a bit different than using an engine that promises 2200hp.

Typhoon will take off with 1700 HP, it will have no worse power-to-weight ratio and wing loading than a F4U, and much better in that regard than a P-47.
Problem is that it will be much slower than the Spitfire with same engine, and much more important, it will be much slower than the German opposition.
 

Shortround6

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Typhoon will take off with 1700 HP, it will have no worse power-to-weight ratio and wing loading than a F4U, and much better in that regard than a P-47.
Problem is that it will be much slower than the Spitfire with same engine, and much more important, it will be much slower than the German opposition.
True but the two American planes were built with 2 stage superchargers of 1940-41 vintage (designed for less than 100/130) fuel and air to air inter-coolers.
The American planes were 'designed" for much more fuel capacity.
The X4FU-1 grossed under 9400lbs (with less than stellar armament) but the early engine was only good for 1460hp at 21,500ft. Of course that is just about the same power as a Griffon II, III, IV only 7,000ft higher.
No armor or protected tanks either. But then the Corsair design work started in 1938.

Engines and a lot of other things made a lot of progress in just a few years.
A Griffon powered Typhoon of 1940-41 would have been much different than Sabre powered Typhoon just in having about 500lbs less engine, a smaller prop and possible carrying less fuel which would have lead to a smaller wing and other changes.

Now if you could have gotten Hawker to not use that 18% wing on the Typhoon in 1940 the speed would have been better from the start. ;)

Now if you know in 1940 that you are going to get Griffon 60 series engines in 1943/44 and fuel that will allow 21lb of boost (leave aside the 100/150 fuel ) you can make all kinds of wonderful design choices (and production choices) on your prototype aircraft ;)
 

tomo pauk

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True but the two American planes were built with 2 stage superchargers of 1940-41 vintage (designed for less than 100/130) fuel and air to air inter-coolers.
The American planes were 'designed" for much more fuel capacity.
The X4FU-1 grossed under 9400lbs (with less than stellar armament) but the early engine was only good for 1460hp at 21,500ft. Of course that is just about the same power as a Griffon II, III, IV only 7,000ft higher.
No armor or protected tanks either. But then the Corsair design work started in 1938.
No quarrels about all of that.
Still, the Typhoon will be taking off with 1700 HP.

Now if you could have gotten Hawker to not use that 18% wing on the Typhoon in 1940 the speed would have been better from the start. ;)

Much better thing than meddling too much in the engine choice.

Now if you know in 1940 that you are going to get Griffon 60 series engines in 1943/44 and fuel that will allow 21lb of boost (leave aside the 100/150 fuel ) you can make all kinds of wonderful design choices (and production choices) on your prototype aircraft ;)

Nobody knew that. Any Griffon was not a sure thing in 1940.
But by 1943, the 2-stage Griffon on a Tempest didn't required the crystal ball.
 

Shortround6

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Hawker (Camm) knew that the 18% airfoil was a mistake in 1940 but he needed the Air Ministry to change it (existing orders). And he needed design staff.
Do you work on a new wing for the Typhoon delaying both the Typhoon and/or the 12 gun wing for the Hurricane and the cannon wing for the Hurricane?
In 1941 things got freed up up somewhat and actual work (not just idea) for the Tempest wing began.

From Wiki so take as you will.
"In February 1941, Camm commenced a series of discussions with officials within the Ministry of Aircraft Production on the topic of the P.1012.[11] In March 1941 of that year, clearance to proceed with development of the design, referred to at this point as the Typhoon II, was granted. At this point, work was undertaken by a team of 45 draughtsmen at Hawker's wartime experimental design office at Claremont, Esher to convert the proposal into technical schematics from which to commence manufacture.[11] In March 1941, the Air Ministry issued specification F.10/41 that had been written to fit the aircraft. By October 1941, development of the proposal had advanced to the point where the new design was finalised.[11]"

and
"On 18 November 1941, a contract was issued by the Air Ministry for a pair of prototypes of the "Typhoon Mark II"; the new fighter was renamed "Tempest" on 28 February 1942.[5][11][nb 3] Complications were added to the Tempest program by external factors in the form of engine issues: the Rolls-Royce Vulture engine and corresponding Hawker Tornado aircraft which was being developed in parallel were both terminated. Due to this previous experience on other programs, the Air Ministry was sufficiently motivated to request that a total of six Tempest prototypes be built using different engines so that, if a delay hit one engine, an alternative powerplant would already be available.[11] This measure turned out to be prudent, as engine development was not trouble-free on some of the variants of the Tempest.[12]

The six prototypes built were as follows:[13][14]

  • One Tempest Mk.I (serial number HM599), equipped with the Napier Sabre Mk.IV engine
  • Two Tempest Mk.II (serial numbers LA602 and LA607), equipped with the Bristol Centaurus Mk.IV engine (LA607 later receiving a Centaurus Mk.V)[15]
  • One Tempest Mk.III (serial number LA610), equipped with the Rolls-Royce Griffon 85 engine (originally planned for the Griffon IIB)[16]
  • One Tempest Mk.IV (serial number LA614), which was never completed but planned to be equipped with a Griffon 61 engine
  • One Tempest Mk.V (serial number HM595), equipped with the Napier Sabre Mk.II engine
The Tempest Mk.I featured other new features, such as a clean single-piece sliding canopy in place of the car-door framed canopy, and it used wing radiators instead of the "chin" radiator.[nb 4] Due to development difficulties with the Sabre IV engine and its wing radiators, the completion of the Mk.I prototype, HM599, was delayed, and thus it was the Mk.V prototype, HM595, that would fly first.

On 2 September 1942, the Tempest Mk.V prototype, HM595, conducted its maiden flight,"

It took until April of 1944 for the Tempest V to start operational flights.
The Tempest was originally intended for the Griffon IIB (used in the Spitfire XII) but aside from just getting experience it is hard to see what the goal was. Putting the Griffon IIB engine in an airframe designed for the Sabre or Centaurus engines is not going to give great performance.

So we know what the Tempest MK III looked like when completed but it was pretty much a Tempest wing/air frame.
Hawker_Tempest_Mk_III.jpg

and it was probably not what was envisioned in 1941/42.

If somebody wants a smaller airframe more suited to the Griffon engine (about 400-500lb lighter than Sabre plus radiator set up and propellers)
It might have been a very good aircraft. But it would have needed to be a higher priority in 1940-42 and needed fore knowledge of fuels of 1944.
 

tomo pauk

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Hawker (Camm) knew that the 18% airfoil was a mistake in 1940 but he needed the Air Ministry to change it (existing orders). And he needed design staff.
Do you work on a new wing for the Typhoon delaying both the Typhoon and/or the 12 gun wing for the Hurricane and the cannon wing for the Hurricane?
A new wing for the Typhoon (or retaining the old) is not a topic here, engine is :)

The Tempest was originally intended for the Griffon IIB (used in the Spitfire XII) but aside from just getting experience it is hard to see what the goal was. Putting the Griffon IIB engine in an airframe designed for the Sabre or Centaurus engines is not going to give great performance.

We already agree on the conclusion that Griffon II will not give the great performance. Especially the Typhoon will be found lacking.

If somebody wants a smaller airframe more suited to the Griffon engine (about 400-500lb lighter than Sabre plus radiator set up and propellers)
It might have been a very good aircraft. But it would have needed to be a higher priority in 1940-42 and needed fore knowledge of fuels of 1944.

The 100/130 grade fuel will do.
The 2-stage Griffon is an excellent match, with the caveat that production of 2-stage Griffon (and Griffon in general) is a major bottleneck; the 2-stage Griffon also means waiting until the winter of 1943/44 in order to have a meaningful number of such engined Tempests.

Smaller and lighter airframe is that of the Fury/Sea Fury, but again this is too late for ww2, unless Hawker makes this kind of airframe 1st, ie. instead of Tempest by 1943.
 

Shortround6

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A new wing for the Typhoon (or retaining the old) is not a topic here, engine is :)
Camm was more interested in the new wing. In 1940 He had the Sabre (problems weren't that bad at the time), He still had contracts for the Tornado (Vulture engine) and was stuffing the Centaurus into the Tornado, but all were crippled by the wing. Sticking a low powered engine into the airframe wasn't going to solve anything.
We already agree on the conclusion that Griffon II will not give the great performance. Especially the Typhoon will be found lacking.
There were contracts for 1960 (?) Tornados. When the Vulture was canceled in July 1941 (?) that may be be the best bet for Stuffing a Griffon into the Hawker airframe. At least the Griffon power will be closer to the Vulture.
The 100/130 grade fuel will do.
This is hindsight. It took over two years to get from 100/??? fuel in the summer of 1940 to figuring out what you could really do with 100/130 in a Merlin or Griffon.
Spitfire XII was being tested in in Sept/Oct of 1942 with a Griffon IIB with 12lbs of boost.
In Sept of 1943 they were testing a Griffon 65 powered Spit XIV at 18lbs of boost.
In the Spring of 1943 they were changing the the two stage Merlins to the 18lb limit.
The 2-stage Griffon is an excellent match, with the caveat that production of 2-stage Griffon (and Griffon in general) is a major bottleneck; the 2-stage Griffon also means waiting until the winter of 1943/44 in order to have a meaningful number of such engined Tempests.
That is true. But it requires the the two stage Griffon. The Knowledge that you can use 18lbs of boost and the thin wing.
Take any one of those factors out and sticking the rare Griffon engines in the big Hawker airframe is a waste of resources. (Griffon powered Spitfire not built)
The thick wing Typhoon was about 40mph slower than the early Tempest both using 9lbs of boost (?) in the high teens for altitude.
 

tomo pauk

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Camm was more interested in the new wing.
Camm was not the OP here. The OP asked quaetions about the engine changes, not the wing change :)
We agree on the necessity of the modern wing for the Typhoon.

This is hindsight. It took over two years to get from 100/??? fuel in the summer of 1940 to figuring out what you could really do with 100/130 in a Merlin or Griffon.
Spitfire XII was being tested in in Sept/Oct of 1942 with a Griffon IIB with 12lbs of boost.
In Sept of 1943 they were testing a Griffon 65 powered Spit XIV at 18lbs of boost.
In the Spring of 1943 they were changing the the two stage Merlins to the 18lb limit.

Okay. Start with +12 psi and work from there.
130 grade fuel predates the 2-stage Griffon.

That is true. But it requires the the two stage Griffon. The Knowledge that you can use 18lbs of boost and the thin wing.
Take any one of those factors out and sticking the rare Griffon engines in the big Hawker airframe is a waste of resources. (Griffon powered Spitfire not built)

It certainly requires the 2-stage Griffon, that is the topic after all. Over boosting of engines is the in-house knowledge at RR, it will start from one level of overboost and go upwards until the limit is reached. RR has also the option of water-alcohol injection, however the availability of even higher octane fuel lessened the appeal of that.
The thin wing Hawker's fighter is a historical thing, no changes needed. I've already acknowledged that production of Griffon engines is a bottleneck.
 

Shortround6

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Okay. Start with +12 psi and work from there.
130 grade fuel predates the 2-stage Griffon.
It does and it doesn't.
The 100/130 fuel showed up in 1941? (the 100 octane fuel in the BoB was NOT 100/130) and there was a very short period of time when 100/125 existed.

The question for the Griffon powered Hawker fighters is when do you know you can go to 18lbs of boost in the Griffon engine. Just because you can run a Merlin at that boost level does not mean you can run the Griffon there without a lot of testing.

The Hercules and Centaurus engines never came close.
The Sabre didn't get to 11lbs of boost until 1944. (and that took 150 octane ?) Some very late Sabres Vs and VIIs are rated higher but use 150 octane. They also needed strengthened internal parts.
 

tomo pauk

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The question for the Griffon powered Hawker fighters is when do you know you can go to 18lbs of boost in the Griffon engine. Just because you can run a Merlin at that boost level does not mean you can run the Griffon there without a lot of testing.

The +15 psi might be an in-between step. Once we have the engine running well there, move on.

The Hercules and Centaurus engines never came close.
The Sabre didn't get to 11lbs of boost until 1944. (and that took 150 octane ?) Some very late Sabres Vs and VIIs are rated higher but use 150 octane. They also needed strengthened internal parts.

Hercules and Centaurus can't compete, if just by the virtue of being air cooled.
These two, as well as Sabre, have the sleeve valve handbrake for the boost levels.
 

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