Build an improved Gloster F5/34

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Which reference do the figures come from? For a start they imply no Hurricanes built between 10 June and 29 September 1939.

Some rather different results from the production reports and RAF contract cards. Cumulative official production by Hawker to end June 1939 was 464, end September it was 594. To end February 1940 it was 884, to end March a total of 951. First official production from Gloster was in October 1939, cumulative official production to end April 1940 was 225, end June it was 448, end July it was 568.

Contract 527112/36, Requisition 26/36, Maker Hawker, Quantity 600, Note: Includes 60+20 for other governments. Completed 8 Nov 1939. L1547 to L2146
Contract 751458/38, Requisition 56/38, Maker Hawker, Quantity 300, Note: Includes 12 for other governments. Completed 15 Feb 1940, N2318 to N2729 (167 Brooklands, 133 Langley) The first Langley built Hurricane was N2318, first taken on charge date was N2320 on 4 October 1939.

Contract 962371/38, Requisition 195/38, Maker Gloster, Quantity 500, Note: Completed 13 Jul 1940, P2535 to P3264
Contract 962371/38, Requisition 195/38, Maker Hawker, Quantity 292, Note: Brooklands, completed 20 Jul 1940, P3265 to P3984 (500 a/c), P8809 to P8818 (10 a/c), R2680 to R2689 (10 a/c), W6667 to W6670 (4 a/c)
Contract 962371/38, Requisition 195/38, Maker Hawker, Quantity 232, Note: Langley, completed 17 Jul 1940 (serials in Brooklands line)
For reference, P8809 to P8818 (10 a/c, Brooklands), R2680 to R2689 (10 a/c, 2 Brooklands, 8 Langley), W6667 to W6670 (4 a/c, Langley). So the third Hurricane contract was split between Gloster and Hawker, I assume Gloster being the subcontractor.

Contract B19773/39, Requisition 195/38, Maker Gloster, Quantity 100, Note: Completed 9 Aug 1940, R4074 to R4232

The 60+20 comment in contract 527112/36 is because the Canadian order received its own contract. Contract 966177/38, Requisition 215/38, Maker Hawker, Quantity 20, Note: For Canada, originally part of contract 527112/36

It is probable Langley only produced metal wing Hurricanes, Gloster was metal wing. N2426 is was the last of the second order with fabric wings. L1877 was the first with metal wings, next was L2026, various other L serial aircraft are marked metal wings.
 
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Hmm. We have replaced the Mercury with a heavier Merlin with a radiator somewhere and replaced the wing with a Spitfire wing and the undercarriage with the Spitfire one. Altered the fuselage to accommodate the forward movement of the centre of gravity. Presumably added more tankage for the Merlin. Perhaps we could finish it off with a Spitfire fuselage…….. Being in the Hawker family Gloster would be more likely to be making Hurricanes of course. So the better F5/34 is a Hawker Hurricane.

The better F5/34 only makes sense if it brings something to the table that is not better filled with Hurricanes or Spitfires. It makes some sense if it uses Perseus production to some end. I would point to the undercarriage which is a matter that can be improved with performance benefits and have it as a complement to the Blackburn Skuas in using the same engine on carriers. Thus it replaces the OTL Sea Gladiators and fighter Fulmars leaving the Fulmar to be the Skua replacement. At least it can soak up the Perseus OTL used on the Roc and free up Sea Gladiator Mercuries for Blenheim /Lysander production. It will be ultimately replaced, in the mind of the Admiralty by the Firebrand, but actually by Sea Hurricanes and Seafires but gives the Royal Navy a working fleet fighter in the first two years of the war. Just possibly it can acquire a Taurus later on but I have my doubts.
 
The FAA and keeping the intended Perseus is the only possible path for the F/5/34 to enter service. Perhaps Hawker will see the opportunity to take the learnings and create a larger successor with the Hercules. And keeping the Skua into early 1942 will see good service in the MTO and at Ceylon when Nagumo sails the Kido Butai nearby without air cover.

Not that the wartime FAA seemed enamored with sleeve valve radials, ditching their Skuas and keeping the Swordfish in production and service well into 1944, when the Albacore was to replace it years earlier. In fact the Albacore production ceased a year before the Swordfish. Postwar, and needs-must the sleeve valve Sea Fury saw wide service, the Firebrand much less.

Bristol did Britain a great disservice by continuing development of the sleeve valve engines once sodium filled valves and other advancements became known in the late 1920s and early 1930s. Give Britain an equivalent to the P&W Wasp series and we might have seen something interesting in single engine fighters, such as Folland designing a fighter around an equal of the R-1830 Twin Wasp.

Pg. 121 https://fredstarr.com/wp-content/uploads/6.-Bristol-Sleeve-Valve-Aeroengines-Hassell.pdf

The Challenge of Mass Production So the future of the sleeve valve looked assured. There was just one fly in the ointment. All these early engines had individually matched cylinders, sleeves and pistons and were hand finished. Finding a combination of materials, processes and techniques to mass produce reliable, interchangeable sleeves with the required strength and wear characteristics proved a nightmare. Fedden would attend the directors' meetings and explain that the last solution, which had seemed so promising, had failed on test but there was this new material or process which he "…was confident would get us out of the wood". This pattern was repeated time after time. Fedden later estimated that it had cost the Air Ministry and Bristol some £2 million to find the answer. This at a time when the Ministry was buying new The Piston Engine Revolution 122 Pegasus and Mercury engines for less than £2,000. Many since have since questioned if it was worth it. One postwar American engineer called the sleeve valve "an excellent solution to a non-existent problem".
 
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Geoffrey Sinclair said:
Which reference do the figures come from? For a start they imply no Hurricanes built between 10 June and 29 September 1939.
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It is from the book "Hawker Aircraft since 1920" Francis Mason. It could very well be typo/misprint ?

Main point is that mucking about with production can really screw up delivery, trying to substitute a plane that flew well over year after another one (even if they could speed things up somewhat ) could move the project time table back over year. The Gloster F.5/34 adds to complication by changing the form of construction, at least for the fuselage.
 
yulzari said:
Thus it replaces the OTL Sea Gladiators and fighter Fulmars leaving the Fulmar to be the Skua replacement.
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This assumes that F.5/34 offers much of an improvement over the Fulmar. It may offer some but the Perseus engine, unknown in 1938, is a dead end.

The F.5/34 using the original engine would be down to around 280-285mph at 6,000ft.
You can tweak that by switching to a medium supercharged Perseus like the Skua used and picking up around 100hp at low altitude.
However once you make the change you are kind of stuck with it. The Sea Hurricanes could use more than 6lbs boost once the 100 octane fuel showed up.
The Perseus was never rated at using more than 3lbs of boost.
It took the Hercules VI to get a significant change in boost pressure with 100 octane fuel.
and even then, A Perseus running Hercules VI cylinders with a supercharger that would flow enough air and on a strong enough crankcase, would have been good for about 1040hp for take off and 1125hp at 6,500ft using 8.25lbs of boost. Problem with that is that takes well into 1941 to get that kind of power and by then it is too late.
Admiral Beez said:
Not that the wartime FAA seemed enamored with sleeve valve radials,
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It may be that they had been burned by Bristol. AS in sold a bill of goods? (Stopping short of saying lied to )
We don't know what the cost of the engines were (although the government was paying for them, not the airframe makers)
However the engines gave a lot of trouble and the Perseus was a back burner engine, Bristol never seemed to spend much time on it after 1938/39.
Too busy trying to sort out the Taurus and the Hercules. Both of which gave a lot of trouble in the early years. Bristol did get the Hercules to a good place but it took a lot of effort.
 
None of that stands scrutiny.

Following the 1939 specs that led to Firefly & Firebrand, there were only a couple of specs issued for new naval aircraft before 1943 and those led nowhere. But the very first proposal for the Firebrand, accepted by the Admiralty in Jan 1940, was Hercules engined, although it was the Sabre that was chosen for the final design. And in 1943 it was re-engined with the Centaurus, with a prototype flying in Dec1943 and the first production aircraft the following year.

The Spec for the Centaurus engined Sea Fury dates to 1943 with the first Sea Fury prototype, SR661, flying on 21 Feb 1945. Spec O.5/43, for a Barracuda replacement, called for use of a Centaurus engine in what became the Fairey Spearfish, which first flew in July 1945 but never entered front line service.

The RN also used over 60 Taurus engined Beauforts and a number of Hercules engined Beaufighters in second line roles, alongside versions with other engines.

And remember that the sleeve valve 24 cylinder RR Boreas/Exe pressure air cooled engine was the engine originally selected in 1938 to power the Fairey Barracuda until RR decided to suspend its development in 1939 forcing a re-engining.

So no, I can't see any evidence that the Admiralty had any strong preferences one way or the other about sleeve valve engines once they finally had control of these matters in 1939. They simply sought to used the best available to them.

The decision to keep the Swordfish in production had nothing to do with the engine preference. As explained elsewhere it even predates the Albacore entering squadron service.

The original Admiralty plan in late 1939 had been for Blackburn to build Albacores as a second source of supply. But by getting them to build Swordfish instead it was hoped to get more aircraft sooner by using the original Fairey jigs now no longer required, and less in the way of strategic materials. But ultimately Blackburn didn't produce its first Swordfish until Dec 1940. They continued to build them until Aug 1944 because of the on going need for an aircraft that could operate from escort carriers and MAC ships until the end of the war.

So Albacores replaced Swordfish on the Fairey production line at the end of 1939. They in turn were replaced by Fireflies in late 1942. In RN service, the Albacore squadrons operated from the fleet carriers and during 1943 were replaced by Barracudas.

The last unit to operate the Albacore operationally was 119 squadron RAF which gave them up in Jan 1945 for the Swordfish III with a much improved centimetric radar that was never fitted to the Albacore. That was only 6 months before the final front line Swordfish squadron disbanded.
 
It often took around 3 years to go from initial concept to flying prototypes let alone into production.
Most aircraft were planed around promised future engines. With a strong suggestion by the Air Ministry in the case of the British, like the Air ministry strongly suggesting that company X use engine Y in their proposal. At times the airframe company would have paper proposals for 2 or 3 different engines to keep them in the running should one of the Air Ministry suggested engines hit a snag.
Sabre was a classic example of this. It was suggested or proposed for use by a number of designs in 1938-39. Partly because it was the most powerful engine in the development process.
It had two competitors, The Vulture which was a bit larger but used fewer rpm and was rated (guessed) at a bit lower power and the Centaurus, which was a bit later in timing.
Unfortunately All three engines stumbled. RR had the Griffon on the back burner and with the success of 100/130 fuel (or the 1940 100 octane fuel) both the Merlin and the Griffon could fill in for the larger engines to a large extent. The Vulture was only about 16% larger in displacement than the Griffon but was hundreds of pounds heavier and with 24 cylinders instead of 12 it was always going to be much more expensive to buy and maintain.
The Sabres troubles are well known and eventually the need to use Sabres in the Typhoon and difficulty in keeping up the number of engines in stock meant all plans for other aircraft to use them had to put on the shelf.
Bristol had to put the Centaurus on hold while they sorted out the Taurus and Hercules, how much they learned helped the Centaurus I don't know but nobody was rushing Centaurus engines into new aircraft in the middle of WW II. Once testing looked good then the plans could go forward.
The British were planning on using Centaurus powered planes against Japan in 1945-46 but that was a big difference than 1943-44.

British production in WW II was a very tight thing. Mistakes were made but in some cases there were repercussions to some changes that are overlooked in some of these discussions.
A lot of work was subcontracted out and it wasn't just a question of the main factory making what was wanted but the question was if the subcontractors could supply the needed items.
And sometimes not just the needed man hours but sometimes the desired changes could not be built (at least economically) on the existing machinery.

A lot of times the best was the enemy of good. Sometimes the line between good and mediocre was a little blurry and got crossed over, but going for the best could wind up with stuff showing up late and in smaller numbers.
 
Some mention of the Hercules.
I get it, more power.
But a glaring issue I see with that engine is that it weighs almost 2000 lbs.
That's about 350 lbs. heavier than the Merlin.
So now we're back to restructuring the aircraft to counterbalance all that weight.
This is why I was hot on the Pegasus in my prior post.
There's only approx. 150 lbs. difference in weight between it and the Mercury, but its capable of making almost the same power as the Merlin that was used in the Mk.1.
Nice thing about the Gloster is that its about 1100-1200 lbs. lighter than either the Spit or the Hurri.
In fact, it's about the same as the 109E.
 
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How about we leave the Gloster F/5/34 as it is, with the exception of an undercarriage redesign to allow flush lower wing surfaces? It was never tested with its intended Perseus engine. Is this design so flawed? With eight guns, excellent visibility and a likely a top speed when fully armoured, armed and fueled exceeding 320 mph, it may be sufficient against many an opponent. She's a good looking bird that I wish some museum had held onto.

Gloster F.5/34

Aviation photographs of Photographer: Joe Barr Collection :
ww2aircraft.net

I think the biggest barrier for the Gloster to overcome isn't its design, but that its manufacturer was acquired by the competition in 1934, who already had a good fighter in the pipe. Interestingly, Hawker proceeded to support the prototype's construction and first flight in 1936, two years after Gloster's acquisition. So, clearly Hawker saw something worth pursuing.

Nevertheless, the only way the F5/34 will see service is if Folland's design is produced and in service before Hawker's acquisition - either at Gloster or if the firm sells off the design to another manufacturer (was that ever done in interwar Britain?). But that's not the aircraft's fault.
 
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Something about the F5/34 doesn't seem quite right.
It has the highest performance (speed) for it's installed power of any of it's contemporary radial engine competitors/contemporaries.
The Mitsubishi A6M2 M 21 for instance needed about 100 hp (13%) more power to do the same speed at about the same altitude.
A P-36B with an experimental engine did just about the same speed about 1000ft and was using a 950hp engine.

Both of these appear to have a tidier engine installation and both had better landing gear set up. Doesn't mean they didn't have other problems.

And we have the problem of looking at the Hurricane which was within a couple of mph while using about 200hp more (22%) more plus using exhaust thrust (maybe not well?)
Granted the Hurricane used a bit bigger wing.
The MC 200 was also very close. But used a wing only about 82% as big. Granted the MC 200 had a few aerodynamic problems.
P-43 was a porker but it had a 223 sq ft wing and needed 840hp at 15,000ft do 300mph and 1100hp at 15,000ft do 328mph

Keep going down the list. The F.5/34 is fastest radial engine fighter of it's size/power anywhere in the world even several years later.

It doesn't matter what Hawker wants to do. If the Air Ministry thinks it was a better airplane they would have ordered it. Or at least done more testing to find out what made it so fast.
The Bristol 146 holds no such interest. it is 29mph slower than the Gloster.

Something else doesn't sound right.

"Compared to its contemporaries, test pilots found the F.5/34 prototypes had a shorter take off run, offered better initial climb and were more responsive and manoeuvrable due to ailerons that did not become excessively heavy at high speed."

Now the shorter take-off run might be explained by the fact that the Gloster was using a variable pitch propeller while some of the contemporaries were using fixed pitch props.
A Hurricane I shortened it's take-off run from 370 yds to 280 yds when it changed from the fixed pitch prop to the two pitch prop.
Likewise the Gloster having a better initial climb might be explained by the difference in propellers.
We do that the Hurricane was several (1-3) minutes faster to 20,000ft regardless of the propeller.
And now we have the question of the Hurricane, which was no faster and heavier by about 1000lbs, out climbing the Gloster by several minutes to 20,000ft?

We don't really know which test flights are being compared but we do know that the Hurricane was being tested with a two pitch prop in Nov of 1938. This may be months after the Gloster F.5/34 was being tested against the other aircraft.


I have already explained that you need a more "finished" product to sell to another company or country. Two prototypes are not a finished product. You need production drawings and tooling drawings.
Even if Gloster had "drawings" that just shows how the parts in airplane look as they are installed in the plane. It doesn't tell you what they look like in different stages. Or tell you what order to make bends in something or what order to drill holes in what order to assemble several dozen (let alone hundreds of pieces). You don't want to be taking 15 parts back off because you didn't realize part 86 had to go in before parts 70-85 were already installed. That is why they have "production drawings". It could take months to do up a set of production drawings.
There were hundreds of drawings needed just for changing the F4F from 4 guns to 6 guns.
 
Shortround6 said:
Something about the F5/34 doesn't seem quite right.
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How are prototype performance stats recorded and verified? Until it's presented to the government I assume the manufacturer measures however and reports whatever they'd like.

I am reminded of the one-off Bloch MB.157, essentially a 316 mph MB.152 equipped with a 1,590hp Gnome-Rhône 14R-4 engine, that somehow reached 400 mph. Apparently an error in metric to imperial conversion or other poor measuring or reporting. Or the prototype was stripped of all armour, armament, radio, most fuel, etc. to achieve a very light weight along with a slight descent? Perhaps that's what Gloster did?
 
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I think you're onto something there.
It's interesting how the performance figures don't match up quite "right", and all around the time Hawker bought out Gloster.
I gotta wonder if ol' Hawk wasn't looking out for their own best interests with all that.
 
Admiral Beez said:
How about we leave the Gloster F/5/34 as it is, with the exception of an undercarriage redesign to allow flush lower wing surfaces? It was never tested with its intended Perseus engine. Is this design so flawed?
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To answer that, we first need to understand what a sleeve valved engine is.
According to Wiki, A sleeve valve takes the form of one or more machined sleeves. It fits between the piston and the cylinder wall in the cylinder of an internal combustion engine, where it rotates and/or slides. The cylinder wall has inlet and exhaust ports, identical to a two-stroke motor. Ports (holes) in the side of the sleeves come into alignment with the cylinder's inlet and exhaust ports at the appropriate stages in the engine's cycle.
So, as you can see, it's basically a more complicated 4-stroke engine design that would be more expensive to rebuild after TBO was achieved, with no additional benefit to weight and/or power.
The Brits certainly worked it out to a more reliable design than the Americans did, but it's still just a more expensive way to make a 4-stroke engine run.
Had the Perseus/Hercules been done as a poppet-type valve arrangement, like a normal engine would've been, we might be talking about them more often than we currently are.
As for landing gear, I say look no further than Focke-Wolf's design for the 190. It's stupidly simple and offers a very stable platform for which the plane to rest upon when not flying.
 
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Elvis said:
Had the Perseus/Hercules been done as a poppet-type valve arrangement, like a normal engine would've been, we might be talking about them more often than we currently are.
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I agree, and Bristol did Britain a real disservice here. But I wonder if the sleeve valve layout was a reason for its cancelation. Several of Britain's best aircraft had sleeve valve engines, such as the Albacore, Beaufighter, Beaufort, Halifax, Typhoon, Tempest and Sea Fury.
 
...and that's because all those aircraft ran Bristol engines.
There was a lot of experimentation with the internal combustion engine during the first half of the 20th century. Look at the Napier Deltic ( ).
Was it the sole reason for the plane's cancelation? No, not solely, but I think it certainly helped (although, at the time, the Brits seem to hold the Sleeve Valve design in higher regard than the Americans did).
As I wrote in my response to Shortround's post, though, there may have been more happening behind the scenes than we are aware of, initially.
 
Given that Gloster was acquired by Hawker in 1934 and the F5/34 didn't fly until 1937, I wonder what Camm was doing? Henry Folland didn't resign from Hawker until the F5 flew in 1937, so perhaps the F5 led to his departure.

Elvis said:
...and that's because all those aircraft ran Bristol engines.
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Not quite. Typhoon and (until postwar) Tempest flew Napier sleeve valve engines. To be fair, Napier (then English Electric) did merge with Bristol, but not until the 1960s.
 
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Admiral Beez said:
Given that Gloster was acquired by Hawker in 1934 and the F5/34 didn't fly until 1937, I wonder what Camm was doing? Henry Folland didn't resign from Hawker until the F5 flew in 1937, so perhaps the F5 led to his departure.
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According to a biography of Folland he left Gloster in 1937 after 16 years. The trigger was the takeover by Hawker generating a feeling that Hawker designs were being favoured over those of Gloster.

Not necessarily surprising. That is business. He who pays the piper calls the tune. Anyone who can't live with that needs to move on.
Admiral Beez said:
Not quite. Typhoon and (until postwar) Tempest flew Napier sleeve valve engines. To be fair, Napier (then English Electric) did merge with Bristol, but not until the 1960s.
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That is not quite the whole story. Hawker received a contract in 1941 for a Bristol Centaurus engined Tornado (In place of the Vulture engine) which flew extensively from Oct 1941. By June 1942 the Centaurus engined Typhoon II, aka the Tempest II, was being given the highest priority. On 28 June 1943 the prototype Centaurus engined prototype Tempest II flew for the first time. Orders for 500 had been placed in Sept 1942 with Gloster. A year later the contract was transferred to Bristol and increased. Other contracts with Hawker followed but there was much juggling of Tempest models on order as well as contract cancellations both during and at the end of WW2.

Ultimately 452 Tempest II came off the production lines. The first production Tempest II came off the Bristol production line in Oct 1944, and deliveries to the RAF began in March 1945. Hawker Langley production followed in early 1945.

The first squadrons, 183 and 247, received them in Aug 1945 only just missing the end of WW2. The majority went to squadrons in 2nd TAF in Germany and to India in 1946.
 

....so, all of the airplanes originally mentioned were Bristol powered...among other engine makes?
 
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The RAF was happily moving on from Mercury engined Lysander to Perseus ones with the spare Mercuries going into the Blenheim production lines, so I doubt if the idea of production Glosters having Perseus ones would put them off. Perseus were also being specified for the Blackburn Botha and initial Bristol Beaufort designs at the time.
 
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