Elvis
Chief Master Sergeant
I'm not concerned with dead end design specs that had to changed and were never used.
The engine the plane actually used was the Mercury, so that's what I'm using as a comparative.
Build an improved Gloster F5/34 (3 Viewers)
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The engine the plane actually used was the Mercury, so that's what I'm using as a comparative.
Shortround6
Major General
OK, lets compare the two engines
Engine........................................Mercury VIII......................Perseus X
take-off power...........................725hp....................................750hp
Power at alt..............................840/14,000............................880/15,500
Weight............................................1010lbs.................................1110lbs
Anybody see a big increase in performance here? A whopping 5% power at altitude?
There were higher powered Perseus engines but just about all of them used a modified supercharger for lower altitude work.
Getting 905-930hp(?) at 6,000-6500ft and another 80-140hp for take-off, while good for torpedo bombers, gives you a real clipped wing chicken (crippled flight) for a fighter instead of a Hawk.
And even in fantasy land if we build Perseus engines that give the exact same power as Hercules engines per cylinder we get just over 800hp at 16,000ft using Hercules III cylinders and supercharger and not much more using Hercules VI cylinders and supercharging until you use 100/130 fuel.
Please note that the Perseus as built ran slightly slower than the Hercules and was never allowed to use more than 3.5lbs boost except for the Perseus XA on take-off.
Now using the specs from the Hercules VI and 100/130 fuel we can get a 9 cylinder engine up to 993hp at 15,500ft. But that is well into 1941.
Engine........................................Mercury VIII......................Perseus X
take-off power...........................725hp....................................750hp
Power at alt..............................840/14,000............................880/15,500
Weight............................................1010lbs.................................1110lbs
Anybody see a big increase in performance here? A whopping 5% power at altitude?
There were higher powered Perseus engines but just about all of them used a modified supercharger for lower altitude work.
Getting 905-930hp(?) at 6,000-6500ft and another 80-140hp for take-off, while good for torpedo bombers, gives you a real clipped wing chicken (crippled flight) for a fighter instead of a Hawk.
And even in fantasy land if we build Perseus engines that give the exact same power as Hercules engines per cylinder we get just over 800hp at 16,000ft using Hercules III cylinders and supercharger and not much more using Hercules VI cylinders and supercharging until you use 100/130 fuel.
Please note that the Perseus as built ran slightly slower than the Hercules and was never allowed to use more than 3.5lbs boost except for the Perseus XA on take-off.
Now using the specs from the Hercules VI and 100/130 fuel we can get a 9 cylinder engine up to 993hp at 15,500ft. But that is well into 1941.
Geoffrey Sinclair
Staff Sergeant
- 941
- Sep 30, 2021
The article has its good and bad guys with too many adjectives for my tastes. Predicting the future is a great way to look foolish but predicting the past is easy.
Singapore Island had a pre war population of around 558,000 people (350,000 in the city) on 225 square miles, Malta had around 241,000 people on 122 square miles. Given the population and that most of the Singapore water supply came from Malaya calling the island a fortress was ignoring reality. At the same time the only viable threat came from the Japanese, who would need to capture bases in places like the Philippines, French Indo China, the Dutch colonies and/or Thailand before they could do more than raid, there would be lots of warning. The IJN had no developed plans to strike European colonies pre 1940, only against the US ones. In naval strength terms the 9 Japanese to 15 American battleships were considered to be an 81 to 225 combat power, against the 21 Anglo French 81 to 441. It was hard to see how a Japanese strike south would not be opposed by at least the Anglo French. Anyway it was widely known as absolute no need to check fact Asian militaries were inferior in all respects, look how bogged down Japan become in China.
The June 1940 events radically changed things, a rough equivalent of expecting Australia to currently have defence plans based on the assumption Indonesia signs an alliance with China allowing extensive basing rights and use for any purpose.
I do not have a peacetime personnel strength for the IJN, in December 1941 it was around 300,000 and for Australia to rely on its own Navy (or even Air Force) would require a credible percentage of the IJN, plus civil personnel in at least the repair facilities even if most ships and aircraft were built overseas. The Australian population in 1939 was 6,960,798 in 1945 was 7,376,567, or about a tenth that of the Japanese home islands.
Australian military personnel (Male / Female / grand total)
9/39, 14,903 / 0 / 14,903
11/41, 364,874 / 3,785 / 368,959
8/42, 634,645 / 21,451 / 656,096
8/43, 685,946 / 46,054 / 732,000
8/44, 649,363 / 47,703 / 697,066
6/45, 599,277 / 44,728 / 644,005
6/46, 132,062 / 11,401 / 143,463
6/47, 54,463 / 949 / 55,412
The Navy peak wartime strength was around 40,000 after starting at around 8,000. According to John Ellis some 1,340,000 served in the military at one time or another.
Apart from the World War I debts Australia had many overseas loans to pay for development, payments for which created considerable pain during the depression.
Australian defence planning in the 1930's was effectively based on the assumptions any threat would come from Europe, the Australian Military would therefore mostly move there and would be part of the Empire military, this required a common doctrine and equipment, US Aircraft were built using all sort of different standards to British ones. Any aircraft sent to Australia were effectively lost to the European strength. Buying from the US was expensive, military orders would be terminated as soon as war broke out and worse probably spare parts supplies as well. Even if that changed the ability to generate US dollar income would be reduced as the local economy switched to a war footing. It is interesting the Australians ordered Twin Wasp engines for their Hudsons which at least gave the chance of local spare parts production, the RAF had no local source of engine spares for their Hudsons. How goes Coastal Command in 1939/41 if the Hudsons are deprived of spare parts? The British had much more leverage with the US than the Australians. Canada had a "special relationship" and was free of the risk of bomb raids. The US were world leading in many aspects of civil aviation but in the second half of the 1930's were falling behind Europe in military types and production capacity as the Europeans dramatically increased their military spending. The decision to make Wirraway provoked a big local backlash "British is Best" was a widely held belief, plenty of "never vote for you again" letters arrived. The opposition died down with the RAF Harvard order and the way the RAAF added its Hudson order to the RAF one. The next hurdle was how many Wirraway did the RAAF need, there was no export market and the 1939 peace time limits on the planned RAAF size. War seemed to be coming, but when?
A European enemy was expected to send maritime raiders into the southern hemisphere, more than just float planes would require the IJN to include one of its 6 carriers in the force and given IJN base locations it would be a raid, carriers operated alone, could be overwhelmed by a relatively small strike force and had inferior aircraft than land based ones, everyone agreed carriers versus land based air power was bad for the carriers. Given the weight of attack shipping would be the main target, a few bombs on land targets were probably not worth the risk.
The RAAF would be expected to provide tactical reconnaissance for the Army, maritime search and strike, even if it had fighters, given their range and the size of the continent they needed plenty of warning to move to the threatened location or lots of bases with around a carrier's worth of fighters in each.
RAAF pre war orders, number, details
18 Hawker Demon order, approved 15 November 1933.
24 Seagull V order (approved 26 January 1934) London order 416 (ordered as 6+6+12) Air 2/1791 says final 12 ordered 1 May 1936 under contract 323214/34. 12 received in 1935, next 12 received starting December 1936.
1 DH.89 Rapide London Order approved 15 January 1935. There should be a second order for 1 or was it civilian leased/bought?
24 Hawker Demon order approved 29 January 1935 (London order 452)
12 Avro Cadet order approved 1 May 1935, London order.
(12) Avro Cadet order plus 3 spare engines, as coverage for delays in Demon deliveries, cancelled, order number reused. A draft Agenda, deferred, request to return documentation made 14 August 1935.
6 DH.60 Gipsy Moth officially built by De Havilland in Australia from a mixture of imported and local parts. Delivered October 1935 to June 1936.
12 Hawker Demon order approved 11 November 1935. London order 452A
33 Avro Anson order approved 11 November 1935, London order 479, which was also a provisional order for Avro Cadets not proceeded with.
5 Avro Anson order approved 11 November 1935, London order 496, dual control for training
10 Hawker Demon order approved 18 August 1936, London order. Air 2/1791 says Air Board Order 524 sent by airmail 15 Oct 1936. Plus 24 conversion sets to dual trainer version under order 532.
10 Avro Cadet order approved 29 August 1936? London Order 525. Air 2/1791 says Air Board Order sent by airmail 15 Oct 1936.
40 Bristol type 149 (Bolingbroke) advanced notification sent 24 November 1936, approved 2 March 1937. London order 550
6 Westland Wapiti order, second hand from RAF, requested 7 July 1937, to supplement the earlier Wapiti orders.
1 Miles Magister order Overseas Indent 584 approved 8 October 1937.
1 Wirraway order, (NA16 prototype offered to RAAF by CAC) approved 11 November 1937
12 Avro Cadet order approved 18 November 1937, Overseas Indent 589. Air 2/1971 says as of 27 Oct 1938 deliveries expected in about a week, contract completed by end of year
10 Bolingbroke order approved 29 November 1937. Mercury VIII engines (Blenheim I) Overseas Indent 591. RAF Bolingbroke orders cancelled in December 1937.
(50) Bolingbroke order changed to 50 Beaufort in February 1938
40 Wirraway order (First) contract signed 15 March 1938 (In January 1937 the government indicated it would place the order, subject to the usual contract negotiations being successful.)
10 Avro Anson order approved 24 March or 5 April 1938, Overseas Indent 613.
40 Avro Anson ordered in 1938, arrived December 1938 to April 1939. Chartered, the RAAF to pay for freight from UK and then to return them (around 45,000 pounds), interim to cover the lack of Beauforts.
60 Wirraway order (Second) approved 29 September 1938. Contract Demand T.465
40 Beaufort order approved 31 August 1938, bringing the total on order to 90. Overseas Indent 657.
(20) Avro Cadet order approved 29 August 1938? Overseas Indent 656, cancelled, to Tiger Moth? Air 2/1791 says as of 26 October 1938 order had not been placed and it would take 6 to 8 months to build them.
20 Tiger Moth approved in Air Board Minute 21 Nov 1938, file RAAF 9/3/10. Britain to build the engines and fuselages, Australia the wings.
2 CAC Primary trainer prototypes, Wackett trainer, Approved 28 October 1938. Contract demand T.493
50 Hudson order, Overseas Indent/London order 680 approved 24 January 1939, but done in October or November 1938.
32 Wirraway order (Third) on 14 June 1939
18 Beaufighter order request to Britain 19 June 1939 Overseas Indent 712, part paid by reducing Beaufort order by 10 to 80 aircraft.
9 Sunderland Overseas Indent 707, approved 18 July 1939.
RAAF Aircraft inventory 1 September 1939, total 246 including reserves.
54 Demon
21 Seagull
82 Anson
7 Wirraway
21 Wapiti
32 Cadet "Avro Trainer"
29 Moth
The case for the pre war orders goes like this, the Demons were already in service, making them a known quantity, they could be supplied in a timely manner, they could be adapted as trainers and as replacements for the Wapiti tactical reconnaissance. The Ansons were a start on the maritime roles and could move to training when better types arrived. Extra trainers were needed and the Wirraway evaded US complications by being locally produced and not intended for overseas service. The long range maritime reconnaissance role was to be filled by the Sunderlands, their prompt delivery is quite a contrast to the time taken for the other pre war orders. Assuming delivery promises had been kept the RAAF would have had a Beaufort maritime strike force with Beaufighter escort all the way to the target located at long distance by Sunderlands. Their longer ranges compared to the single engine fighters would make it easier to move the forces around Australia.
The Empire air force program had two parts, offering lots of free trainers if the RAAF would pay for their use and the provision for nominal RAAF units in the RAF supplied with RAF aircraft plus at least some payment of wages, meaning outside of Australia there would usually be no higher officially RAAF unit than a squadron, though senior RAAF men might end up in command of larger units. Not what the pre war RAAF expected or wanted. The Australian Army deliberately created a full corps headquarters and associated corps troops to try and ensure its expeditionary force stayed together, one reason 3 RAAF squadron was sent overseas in 1940 and retained its RAAF number for the war.
The case for a new organisation to build the Beaufort is it gave Australia a second production source though geared to only license build (they did a lot of modifications), CAC could design and build, with De Havilland expanded to build Moths for training gave the country 3 sources and chances for any good De Havilland designs. The cost was the inevitable problems from inexperience which would only be a big problem if war came quickly, the plan was first machines delivered in 1940, production rising to 20 per month in September 1941 under peace time single shift conditions. There was no follow on order as of 1939, just like no follow on orders of Spitfires etc. when they started production, with the expectation the 2,000 HP fighters would take over "soon". Given the pace of aircraft development by end 1941 there would probably be a better design to shift to. The article says the Beaufort program start was "ill-informed and incoherent" partly due to the decision to go with the designed Taurus engine, what chance the Beaufort would be in Australian peace time production in 1940 with the delay due to the necessary design changes to use Twin Wasps? Producing Twin Wasp for Beauforts was suggested in a 29 September 1939 cable from Britain, given problems in ramping up Taurus production and starting the Australian line. On (2?) 18 October Australia said no, (24?) 23 October 1939 cable arrived from Britain requesting a change of mind. Then on (3?) 9 November advice there was plenty of Taurus available crossed the advice Australia had authorised twin wasp production on 31 October, but for Beauforts from number 51 onward.
Given the complexity of torpedoes the peace time requirements were best supplied from Britain, who in any case were planning to use the Australian built Beauforts in the Far East and so would have the relevant supplies.
CAC completed Wirraway number 132, the last of the pre war orders, in October 1940 and that was with accelerated production. For Australia to lay down a fighter production line in 1939/40 that could be useful as an air superiority aircraft in the two to three years it would take to hit peak production would mean the Spitfire and that would require imported engines given the speed of Merlin development.
The article does not mention the Brewster Bermuda expected to arrive in 1941 and replace the Wirraway in combat units, nor the Vengeance the order was amended to, with some optimistic delivery schedules. Also no one expected the Beaufighter to be air superiority, more night fighter and bomber destroyer. The Australians built 108 Merlin June 1947 to May 1952. Nene production started in December 1948
No one was willing to sell or at least base fighters in Australia 1939 to 1941, few were interested in shipping anything but unwanted, trainer and maritime reconnaissance types, there were far more other places that needed combat aircraft and with Singapore, Manila etc. expected to hold for some time, plenty of chances to send things later.
US Alternatives noted, the DB-7 used the Twin Wasp, the A-20 used the more powerful R-2600, ranges smaller than the Beaufort. DB-7 production began in October 1939, A-20 in December 1940, B-25 and B-26 production began in February 1941, the B-25 was considered quite good from the start, the B-26 not so. No mention of other alternatives like the Martin Maryland (September 1939), only the designs that later proved to be very useful. Easy now to see what the winners were.
The only reference found so far about RAAF Defiants is from British Cabinet document CAB/66/10/10, Secret W. P. (40) 279, 21st July, 1940, available online at the British Archives, talking about the RAAF after "Defiant Type", it was about a meeting called by the Australian representative to co-ordinate the Dominion requirements for aircraft from the United States, not Britain. The meeting was held in New York.
Deciding Australia needed and could obtain modern fighters 1939 to 1941 ignores the laws of supply and demand at the time, plus as of 1939 there was only 1 British or US fighter design in production that could stay current through the war. If war came the RAAF initially needed to be able to patrol large areas of ocean and help the army. RAF and RN doctrine meant maritime strike were torpedo bombers, the US had the Devastator. The distance from the rest of the world that hindered obtaining aircraft should allow adjustments to be made before the situation became too dangerous.
If no RAAF fighters were such an obvious problem to say mid 1940 then surely so was no aircraft carriers, submarines, tanks, heavy artillery etc. It is the dilemma of smaller countries, the bigger ones can usually build more and make improvements far faster, making your production insignificant and obsolete, but there will always be the time you really need things and no one else can supply them.
Perseus was also of the greater diameter, 55.3in vs. 51.5in for the Mercury. Add the 100 extra lbs for the engine weight, and all and any supposed gain of performance - both speed and RoC - is cancelled.
Early Perseus engines used the same S/C as the high-altitude Mk.X (that, as far as actual use, went nowhere), but with lower drive ratio. The Mk.Xa used the cropped S/C but with the higher drive ratio (see here).
The end result was similar, all the in-service marks being 'set' for the low-altitude power, but hopeless above 10000 ft. In taking advantage of the 100 oct fuel, Mercury was far better.
yulzari
Tech Sergeant
This does rather enforce my view that one needs to look for less aeroplane behind the engines one could get than hoping to find more powerful engines to put on the front of the airframe. To me the obvious is the Vickers Venom. The Mercury is less than 9cm wider than an Aquila, albeit noticeably heavier. The Pratt & Whitney Twin Wasp Junior is even narrower than an Aquila.
Shortround6
Major General
They built about 7(?) Aquila engines total, I don't think more than 2 had the same specification/standard of build. And they didn't work all that well. Combine that with the zoo show of the entire sleeve valve manufacturing in 1939/early 1940 and the chances of getting anything usable out of the Venom is about zero.
The Twins Wasp Junior was skinny. Most went around 1100lbs so power to weight was not good. Aside the The US navy the main customer were the French (they loved small 14 cylinder radial engines) and the British inherited a bunch of French contracts and a bunch were stuck in Miles Master trainers and few other odds and sods.
Most the later engines were good for 825hp at take-off and 825hp at 7200ft military power.
Now perhaps you can put less airplane behind the engine but if you want eight .303s, decent fuel, armor seat back, BP glass and even horse hair and glue on the fuel tanks you need more airplane than most of the 1936-39 planes offered without loosing a lot of performance.
yulzari
Tech Sergeant
The Venom was made for the same requirement F5/34 as the Gloster and seems to have done as well if not better on far less power. Not just popping a Mercury or Twin Wasp Junior on the front of course. The extra weight or diameter will need some reworking of the fuselage. The Aquila is, crudely, half a Taurus (or rather the other way round) and indeed is not going anywhere useful but the airframe was excellent so the suggested possible greater alternatives will enhance the performance. Not to mention the small span and excellent deck landing quality estimation may tempt the Royal Navy for the Nimrod replacement too. Vickers and Supermarine are too busy to make it but Glosters have the OTL Gladiator capacity which might be spared and Bouton Paul the Roc production line. The US Navy used single seat Spitfires to spot for naval shore bombardment so just perhaps the Venom could cover the Lysander's tasks with 2x250lb bombs too and do so more survivably. It would be easier to make an improved Venom than an improved Gloster which needs proper retractable wheels and more power which can, in period, only come at the expense of OTL Merlin engined types.
The issues of armament, armour and self sealing tanks apply to the Gloster F5/34 as much as to the Vickers F5/34. I agree that the Perseus gives little more than the Mercury which is both mature, admittedly at the end of it's development capacity and am aware that the Twin Wasp Junior is an unlikely choice strategically being of foreign manufacture.
Just stretching the AH rubber band a bit further, could it be suitable for Australian production with a licence built Mercury? We are looking at A6M/MC200 power here.
Shortround6
Major General
a 15.6 liter engine or about 71% of the size of the engine in an AT-6, Harvard or Wirraway. Granted it turns at higher rpm but the sleeve valve cool aid was a strong batch for this one.
Elvis
Chief Master Sergeant
I suggested the 1535 because it was a 14 cylinder engine that was closer to the size and weight of the Mercury IX engine that ended up in the F.5 than the 1830, which was being suggested as a replacement for the Mercury, in the hands of the Aussie's.
Sure, the 1830 made more power, but it was also WAY heavier. Even though the 1535 doesn't make the power of the 1830, the potential is there to make more power than the Mercury and since that's the engine the plane ended up with, that's the benchmark I'm measuring by.
