Build an improved Gloster F5/34 (2 Viewers)

[Shortround6]

I'd argue a Twin Wasp would be better.

Because the P-36 with a Twin Wasp was ever so much better than the early P-40 with an Allison?

 

[Elvis]

Indeed. Some bright Aussie paintwork will be needed, like the dazzle scheme used on this Buffalo

View attachment 814048

...Or in modern day at Qantas.

View attachment 814039

Or go RAAF anniversary blue (skip the red strips) and swap out the roundels for 'roos.

View attachment 814047

It's Oz. Leave the roo's there and call them Roondells

 

[Admiral Beez]

Because the P-36 with a Twin Wasp was ever so much better than the early P-40 with an Allison?

The Twin Wasp would be better because we've already got two Merlin fighters. The only reason for putting the F5/34 into service is that it provides a benefit that does not compete with existing, and better aircraft. That's why I've recommended it to CAC and P&W to get it away from the British Air Ministry's priorities for Merlins and Bristol engines.

 

[Shortround6]

The Twin Wasp would be better because we've already got two Merlin fighters. The only reason for putting the F5/34 into service is that it provides a benefit that does not compete with existing, and better aircraft. That's why I've recommended it to CAC and P&W to get it away from the British Air Ministry's priorities for Merlins and Bristol engines.

When????
You keep recommending a totally fictitious version of the Twin Wasp engine.
You don't have the choice of the 1940-41 versions of the Twin Wasp in 1938.
You NEVER have the choice of 1250lb 1200hp Twin Wasp at anytime in it's history. Wiki is wrong.
The Mercury engine is 1938/early 1939 is not a bad fighter engine. What is has is no growth.
840hp at at 14,000ft is not bad in 1938. Now can you wait for a 'better' engine?
And what is the 'better' engine going to cost in weight?

 

[tomo pauk]

You NEVER have the choice of 1250lb 1200hp Twin Wasp at anytime in it's history. Wiki is wrong.

I was appalled with the last sentence quoted there. Appalled, I say.



Whoops, I've proved you right.

 

[Elvis]

If we're giving the Gloster to CAC the Australians will never want a Bristol engine. And with the 1940-start of P&W Twin Wasp production in Australia, the Wright R-1820 Cyclone is out. I'd like to see a performance comparison between Twin Wasp and Bristol-powered Beauforts.

I think this is the best chance of getting the Gloster F5 into service. We've removed it from the British Air Ministry's oversight, taken over the rights, drawings and any tooling from Gloster's new owners at Hawker Aircraft and thus removed any internal company competition with the Hurricane, and replaced its imported Bristol engine with a domestically produced engine of superior power and reliability.

The challenge is how do we install a longer and heavier Twin Wasp into this airframe, shown below with a Bristol Mercury.

View attachment 814064

Perhaps we can move the wing spar and cockpit backwards. Or stick a lump of weight in that fat tail. I like the incline from the windscreen to the nose for visibility, which should be keepable with the P&W diameter. It would be handy to see a cutaway of the Gloster, as perhaps there's empty space behind the engine like on the Skua.

Here's a P&W Twin Wasp. Fourteen cylinders. 30L, 59 in length, 48 in diameter, 1,250 lb (dry), 1,200 hp. And here's what we're trying to replace. The Bristol Perseus. Nine cylinders. 25L, 49 in length, 55 in diameter, 1,025 lb (dry), 905 hp. Doesn't that American engine look space-age by comparsion?

View attachment 814067View attachment 814066

Are we giving it to Australia? I had no prior knowledge of this. When I mentioned the Pegasus engine, I assumed aircraft that was designed and built in the UK, would be flown by said UK forces.
Seeing how the Pegasus was similar to the Cyclone in displacement, configuration and power, it would make more sense to use an engine already available in the UK, as opposed to importing one in from the US.
...and what family of Bristol engines were the Aussies against? The poppet valve engines or the sleeve valve engines?
Bristol made both.
I could see if it was the sleeve valve engines. That was a troublesome valve train. Why it's pretty much extinct anymore, while almost every reciprocating engine on the planet now is a poppet valve engine.
Both the Mercury and Pegasus were Poppet valve engines.
...however...
IF we are giving the whole design to CAC, then yes, it makes sense to use the R-1830, since its already being built there.
So how do we make a plane work with a 1438 lb. engine (specifically R-1830-S3C4G) replacing one that was 1065 lbs.(Mercury IX)?
You could start by pushing the firewall back. Possibly behind the leading edge of the wing (if that's possible).
If you can push the firewall back a foot (will probably preclude moving the cockpit back a bit, too), that will allow you to install the longer engine, while the overall length of the airplane remains the same.
This gives the heavier engine less of a "lever" for which to move the CG of the aircraft.
Pushing the cockpit back will help counterbalance that extra 373 lbs., too.

 

[ThomasP]

Simply adding armour behind the pilot - similar in layout and weight (125 lbs?) to that in the Hurricane and Spitfire - will make up for 80 lbs(?) of the increased weight of a heavier engine installation. As already mentioned up-thread, the addition of ballast in the tail would have a significant effect also, just at a rough look it seems like it would be at about a 4:1 ratio - so that is another 200 lbs for 50 lbs?. Move the avionics & O2 installations farther back if practical.

Maybe?

 

[Admiral Beez]

Are we giving it to Australia?

I am, FWIW. Anyway, start below.

Build an improved Gloster F5/34

If we're giving the Gloster to CAC the Australians will never want a Bristol engine. And with the 1940-start of P&W Twin Wasp production in Australia, the Wright R-1820 Cyclone is out. I'd like to see a performance comparison between Twin Wasp and Bristol-powered Beauforts. I think this is...

ww2aircraft.net

How about armament? The CAC Boomerang had 2 × 20 mm Hispano (locally made) cannons and 4 × 0.303 in (7.7 mm) Browning machine guns. The F5/34 was intended for 8 x 0.303 in., but perhaps the Australians will up the armament.

 

[SaparotRob]

Because the P-36 with a Twin Wasp was ever so much better than the early P-40 with an Allison?

I'm gonna say "yes".

 

[Admiral Beez]

I'm gonna say "yes".

Me too, if the Hawk can wait for the better Twin Wasp.

HAWK 75:-- PROMISE UNFULFILLED?

"The most advanced production version of the Twin Wasp installed was the R-1830-17 engine, which developed 1,200. The -17 engine represented only the very formative stages of R-1830 development. The Hawk 75 never benefited from the later R-1830 versions, including the single-stage, two-speed supercharged R-1830-90, let alone the two-stage, two-speed R-1830-76, which gave the Grumman F4F Wildcat a new lease on life. The presence of this engine allowed the Wildcat to take on the A6M Zero at higher altitudes.
The empty weight of the Army's standard P-36C was 4,620 lbs. empty, 5,734 lbs. loaded. Weight for the folding-wing F4F-4 version were 5,895 lbs. empty and 8,762 lbs. loaded, although the earlier F4F-3 was somewhat lighter. In a Navy proposal Curtiss estimated a top speed of 351 MPH for a navalized Hawk equipped with the -76 engine."

Under CAC, the Gloster F5/34 will continue development with the contemporary Twin Wasp, until the Grumman Wildcat's two-stage, two-speed R-1830-76 is available.

 

[Shortround6]

Me too. If the Hawk (and the Gloster F5/34) gets the right Twin Wasp once it's available. Until then, the Gloster F5/34 will continue development with the contemporary Twin Wasp.

HAWK 75:-- PROMISE UNFULFILLED?

"The most advanced production version of the Twin Wasp installed was the R-1830-17 engine, which developed 1,200. The -17 engine represented only the very formative stages of R-1830 development. The Hawk 75 never benefited from the later R-1830 versions, including the single-stage, two-speed supercharged R-1830-90, let alone the two-stage, two-speed R-1830-76, which gave the Grumman F4F Wildcat a new lease on life. The presence of this engine allowed the Wildcat to take on the A6M Zero at higher altitudes.
The empty weight of the Army's standard P-36C was 4,620 lbs. empty, 5,734 lbs. loaded. Weight for the folding-wing F4F-4 version were 5,895 lbs. empty and 8,762 lbs. loaded, although the earlier F4F-3 was somewhat lighter. In a Navy proposal Curtiss estimated a top speed of 351 MPH for a navalized Hawk equipped with the -76 engine."

My objection to this P&W R-1830 in the F5/34 train of development is it requires a time machine. At what point in time do the people in charge of the airframe project KNOW when the improvements to the R-1830 are going to happen?
This is one of the classic "what if" problems.
If company (or government) had known in 1938 that engine X with YYYY hp would be available in 1941-42 then they should have adopted the plane in question in 1938 and used an earlier, low powered version until the newer, better version was available.
The R-1830-76 that gave the F4F a 'new lease on life' was actually a developed version of the R-1830-19 which needed a lot of work. So did the -76 engine. The two stage supercharger AND THE INTERCOOLERS were being installed in 1939. Weight for the -19 is not available but the -76 was about 1550lbs, not including the inter coolers. Please note that P&W did not develop/introduce the Two speed supercharger until AFTER they were producing the 2 stage engine. There was no two speed engine until after they had the 2 stage engine in limited production for the F4F in the spring/summer of 1940. It had been announced earlier and they may have taken orders for it but it was not delivered until late 1940.
Starting to build a factory and tooling for plane to use the R-1830 in early 1939 on the hopes that P&W would develop a two speed engine seems like a big gamble.
The R-1830 two speed had a few problems as a fighter engine. The 1200hp started to disappear over 5000ft. Even with a two speed supercharger it was down to 1050hp at 13100ft.
Early radial engines had a lot of drag and little or no exhaust thrust. Both were fixed (somewhat) but to use 1942 fixes to justify a 1939-40 adoption twist things.

Curtiss estimated a lot of things. Curtiss was having problems with Curtiss 75s (P-36s) landing on rough ground let alone smacking down on carrier decks.

 

[Admiral Beez]

Starting to build a factory and tooling for plane to use the R-1830 in early 1939 on the hopes that P&W would develop a two speed engine seems like a big gamble.

I envision that like with the Beaufort, the Australians planned to use a Bristol engine for the CAC F5… until this engine is deemed unavailable, leading to tooling up for the Twin Wasp. So, we may see the CAC F5 fly with a Bristol engine, but modified in Mk 2 form with the P&W Twin Wasp.

 

[ThomasP]

I do not know if my timeline is correct, but if my information is correct the first DAP built Beauforts were delivered in mid- to late-1941?? The first British built Beaufort pattern airframe was delivered to Australia sometime in late-1939 or early-1940, and I believe part of the delay (if there was one) was due to having to wait for quantity shipments of the R-1830 engines from the US. The US built engines were in in demand at the time for various US built aircraft. Assuming a similar timeline that would mean that the improved F.5/34 would not be available any sooner than the DAP built Beauforts?

If the Australian F.5/34 build program was begun significantly before WWII then DAP and/or CAC would have to be established much sooner - I think. When were DAP and/or CAC started, and when did they begin production?

EDIT (changed 1939 to 1940 per EwanS's post below)

EDIT (changed 1940 back to 1939 per Geoffrey Sinclair's post below)

EDIT (changed to late-1939 or early-1940)

I'm so confused!

 

[EwenS]

The idea for CAC only arose in 1935 with the company being established in 1936 and opening its first factory in Sept 1937. Wackett joined in 1936 when a company, Tugan Aircraft was acquired, which had produced just 9 aircraft between 1933 and 1936. He then led a group to Europe and the US in 1937 looking for an aircraft that would:
1. Suit Australia's defence needs; and, perhaps more importantly
2. Was within Australia's capabilities to produce.

From that came the Wirraway. By July 1939 it had produced just 3 of this type.

DAP (aka the Government Aircraft Factory) was formed in July 1939, following a March 1939 Govt decision, specifically to produce the Beaufort in Australia, selected in place of the previously intended Blenheim. A whole organisation needed to be set up to build it. The plan involved 600 sub-contractor located in centres up to 1,000 miles apart, feeding parts and sub-assemblies into the final assembly plants.

In Sept 1939 the Beaufort Division of GAF had an empty office, no trained executives, workshop personnel or assured supplies of aircraft materials and plants.

The initial July 1939 order was for 90 for the RAF and then 90 for the RAAF. In Oct 1939 it was decided that the RAAF aircraft would be built with 1,200 up P&W Twin Wasp S3C4-G civil rated engines. The pattern aircraft from Britain, L4448, did not arrive in Australia until April 1940, and it was delivered engineless. A second planned delivery with engines was never made. May 1940 saw the embargo on export of strategic materials from Britain. This relaxed slightly after the BoB. So a new source of engines, propellers and undercarriage oleos had to be found, for which Australia turned to the USA. Ultimately there were some 1,600 modifications made to the Australian Beaufort.

The result of all these delays was that L4448 converted to take Twin Wasps didn't fly until 5 May 1941. It was 22 Aug 1941 before the first Australian built aircraft, T9540 intended for the RAF, came off the production line (one of 20 airframe kits sent out by Bristol) at Fisherman's Bend factory followed on 15 Oct by the first from the Mascot production line.

 

[tomo pauk]

So a new source of engines, propellers and undercarriage Oreos had to be found

The undercarriage Oreos are a b!tch to find even today.

 

[EwenS]

The undercarriage Oreos are a b!tch to find even today.

F*****g auto correct I even changed it once. Now corrected.

 

[Geoffrey Sinclair]

RAF specification F5/34 issued for tender 16 November 1934, 3 types ordered Gloster F5/34 first flight December 1937 (second fully armed prototype in March 1938), Bristol 146 first flight February 1938, Vickers venom first flight June 1936, unofficially MB.2 first flight August 1938. The overall efficiency of the Gloster design would have been proved in mid 1938.

In 1935 a proposal was put to build aircraft and their engines in Australia, the Commonwealth Government convened conferences as well as industry undertaking discussions, this resulted in the formation of the Commonwealth Aircraft Corporation on 17 October 1936.

Starting in February 1936 a delegation was sent on a 5 month tour to visit overseas aircraft industries to determine what design to manufacture. Italy, France, Germany, Czechoslovakia, Holland, Britain and the United States were visited. The Australians wanted a modern but generally proven design, setting up a new industry was hard enough without the complications of design alterations or worse cancellations.

In January 1937 the Australian government indicated it would order the North American design as the Wirraway, subject to the usual contract negotiations being successful. Construction of the Melbourne factory began in April 1937 and the initial buildings were ready for occupation in September, further expansions occurred pre war, a near doubling of the floor space. An order for 40 Wirraway including engines was approved in January 1938 and the contract signed in April 1938, the first engine was built in January 1939, the first Wirraway flight on 27 March 1939, official delivery in July. With 36 engines and 33 Wirraway built by the end of 1939.

Meantime a second production company was set up. In early 1939 a British mission to Australia arrived for an inspection, submitting their report on 18 March 1939, with the British Government confirming general agreement with it on the 24th, the same day as the Australian government announced the decision to produce Beauforts in Australia. Bristol had actually received an instruction to proceed on 26 January. The proposed plan was to build 180 Beauforts in Australia, firstly 90 for the RAF then 90 for the RAAF, plus spares, costs to be equally divided, first machines delivered in 1940, production rising to 20 per month in September 1941 under peace time single shift conditions. 250 Taurus engines were to be ordered from Britain to bridge the gap until locally supplied Taurus engines were produced. Australia launched its production organisation to build the Beaufort on 1 July 1939, the Aircraft Production Branch of the Department of Supply and Development.

Then came the Taurus problems and the mid 1940 crisis. The decision to build the Pratt and Whitney R-1830 Twin Wasp in Australia by the Commonwealth Aircraft Corporation (CAC) was taken on 31 October 1939, Britain had earlier asked for this, Australia had said no, Britain asked for a reconsideration, Australia said yes with the acceptance cable crossing one from Britain saying do not bother Taurus doing better, but by that time announcements had been made. Ideas for fitting it to the Beaufort date from the March 1939 proposal to build Beauforts in Australia given reports of problems with the Taurus engine. The October decision assumed the first 50 Beauforts would have Taurus engines, the remaining 130 Twin Wasp but on 16 July 1940 the RAF agreed to accept all 90 with Twin Wasps, the formal RAAF order was made on 20 July 1940 for 90 Beaufort mark III with Twin Wasp engines. At that stage the mark I was for Beauforts with Taurus 2 engines, mark II for Taurus 3. In December 1941 the designations were mark II for RAF Beauforts fitted with S3C4G Twin Wasp engines and mark V for RAAF Beauforts fitted with SC3G Twin Wasps.

A Bristol built pattern aircraft (RAF serial L4448) arrived in Melbourne on 25 December 1939, permission from the Air Ministry to assemble and fly it was given on 14 May 1940 and it was first test flown with Twin Wasp engines on 5 May 1941. The Bristol Twin Wasp prototype N1110 initially used the Twin Wasp version Australia was going to build when first flown on 23 November 1940, and after these test flights were completed switched to the version the RAF was going to use. Britain ultimately supplied drawings and manufacturing data, jigs and tools, ten sets of fabricated detail parts, including proprietary bought out parts with certain exceptions and ten sets of unfabricated detail parts.

Australian Twin Wasp production started with 1 in November 1941, then 4 in December and 148 during 1942. Beaufort production started in July 1941, with 10 built by the end of 1941 and 198 in 1942. Beauforts,

Mark	Twin Wasp	Propeller	Turret	From A9-	to A9-	Built
V	S3C4-G	Curtiss Electric	Mark 1E	1​	50​	Jul-41 to May-42
VA	S3C4-G	Hamilton Constant Speed or De Havilland 3E50	Mark 1E	151​	180​	Oct to Dec-42
VI	SIC3-G	Curtiss Electric	Mark 1E	51​	90​	May to Aug-42
VII	SIC3-G	De Havilland 3E50	Mark 1E	91​	150​	Aug to Oct-42
VIII	S3C4-G	Curtiss Electric	Blenheim V	181​	700​	Nov-42 to Aug-44

MP1472/1 15 part 4 says only Hamilton propellers used. The forced change from Taurus to Twin Wasp caused considerable delays, compounded by the 1940 crisis, getting engines from the US was much less than the time needed to redesign and test the new engine installation.

While 60 more Wirraway were ordered in September 1938 the CAC plan was always to graduate from trainer to modern fighter, with an eye on using the Twin Wasp, a 1938 investigation of a Twin Wasp fighter version of the Wirraway expected to have a top speed of 250 knots. A 1939 twin engine fighter top speed 300 knots. The CA-4 bomber initially assumed it needed 3 Single Wasp engines because of supply issues, but used Twin Wasp, first flight September 1941, the CA-11 version, first flight July 1944, also used Twin Wasp.

The CA-15 fighter design initially expected to use the Wright R-2600-B and be a development of the Boomerang, order placed in November 1942 cancelled in February 1943, replaced with a new design using the Pratt and Whitney R-2800 with turbocharger, in August 1944 the US indicated the R2800-57W engine chosen could not be supplied, CAC thought about the Centaurus but went with the Griffon, endured a three month suspension of the order and finally flew it in February 1946.

Assuming somehow as well as the Beaufort the Gloster design was selected in March 1939 for Australian production, along with the Twin Wasp engine, then the engine project starts about 7 months earlier than historical with less chance of war caused interference. Engine production from April 1941 or slightly earlier, the hundredth Wirraway was built in September 1940, even allowing for redesign from Mercury to Twin Wasp, tooling time etc. it would mean airframes are being produced ahead of engines, imports would be needed. This assumes Gloster provides at least one of the prototypes fitted with a Twin Wasp in early 1940 at the latest, but note while Bristol did provide some parts to help start Australian production Gloster could not. Any required parts etc. from Britain not in stock or on the way in early May 1940 would not turn up until the end of 1940 at least.

The designation CA-5 was used for Wirraways A20-103 to 134.

The RAAF had ordered from Bristol the proposed General Reconnaissance development of the Blenheim I later called the Bolingbroke, when that was cancelled at the end of 1937 the order was changed to Beaufort and in August 1938 raised to 90 aircraft with the idea to add another 47 later., instead this order was whittled back in 1939 and finally cancelled in 1940 in order to pay for more Hudsons and free funds for the 1939 order for 18 Beaufighter.

 

[Shortround6]

Thank you to both EwinS and Geoffrey Sinclair.

I will note that the Wirraway engine was a 9 cylinder R-1340 with 146mm x 146mm cylinders and max rpm of 2250. R-1830s used 140mm x 140mm cylinders, so the change may have been rather easy once they had the machinery.
The R-1830 engine used in the Australian Beauforts was the first 2 speed R-1830 sold/mass produced. There was only on previous 2 speed engine with no recorded installations.
The R-1830s that were shipped to England (and sunk?) for their Beauforts were a single speed model of 1050hp for take-off.
If the Australians had had the misfortune to start things just a bit sooner and gotten stuck with the Taurus engine (either imported or heaven forbid, trying to manufacture) things might have come to a screeching halt. At best an even larger delay while they actually switched engines.

The CA-15 with the R-2600-B was never going to be more than mediocre. Production starting in late 1943? It was 1-2 years late.

Trying to build a more complicated aircraft than the Wirraway as a first aircraft was just going to delay things. They were not going to get a better Boomerang earlier.