January 1936: build your RAF

[Shortround6]

I pretty much agree with that.

The Twin Wasp was about 10% heavier and a bit bigger in diameter which cut into the extra power it offered making the performance difference rather small. The extra supercharger gear on the twin wasp (depending on version?) gave more power at well above torpedo bombing height. But the timing of the airframe doesn't really allow much change from the historical even with an engine change.

The whole question of wither the sleeve valve was really worth the cost may never be answered but was marginal at best. The sleeve valve solved a lot of problems the poppet valve engines were suffering from in the late 20s or very, very earlier 30s but the time and cost of bringing the sleeve valve to production status meant the the problems with the poppet valves had pretty much been solved by the time the sleeve valves went into production.

While the Beaufort was a nice advance over the Blenheim it wasn't enough of an advance to to keep up with the needs of WW II combat for very long.

 

[parsifal]

Beafort was fine for our requirements until the end of the war. We were somewhat envious of the later marks of b-25, but there was an immense amount of pride in the CAC Beaforts. We could have done better, but for the engine issues that dogged us from the start. The intended replacement for the Beafort was the CAC CA4 and later the CA11 (basically an improved CA4, it was to be named Woomera). But this was finally dropped in 1944, though its test flights showed a fair amount of promise. if the Woomera had been ready by the latter part of 1942, it would have been a remarkable achievement for the Australians, easily the best overall bomber in the PTO at that time. as it was, i would consider the Beaforts in the SWPac at least one of the best at that time

 

[Amur_Tiger]

New to this site but I've been developing an interest in aviation and in particular their engines, so without further ado.

Create a Royal AeroEngine establishment specifically for the solving of common problems and challenges for engine designers, breaking it down into 3 main categories.

1. Supercharger development. RR, Bristol and Napier all could have benefited from effective superchargers but in the end only RR really had access to this. To motivate the employers of those skilled engineers to 'share with the rest of the class' a profit-sharing setup would be offered where the company would receive a share of the profit based on their contribution of engineers to the team as well as the performance boost offered to the engine. This team would focus on one engine at a time until they'd developed the best feasible supercharger for that engine before moving onto the next, from another company.

2. Production techniques and reliability. This would be aimed at easing the shift of an engine from development to mass production by having the engine manufactures provide them with a technique to build an engine component and after attempting to follow the instructions would grade the result based on the amount of time required and how close it is to spec. They'd also hopefully have a decent amount of knowledge on mass production techniques and how best to mass produce various parts to spec. This is particularly aimed at helping Bristol and Napier get past their sleeve valve issues.

3. Materials development. Mainly this would be to provide more support to Special Metals Corporation in developing Nimonic as early as possible but this would also be about alerting the engine manufactures about what exactly they were developing and allow them to prepare designs or plan adjustments to existing designs to incorporate these new materials.

I'd blur the lines between Fighter Command and Bomber Command, allowing either to have squadrons of the other's aircraft organically a part of their organization but stressing that their purpose as a command would remain the same. Fighter Command bombers wouldn't be targeting anything that didn't directly aid their goal of achieving air superiority ( runways, radars and that's it ). Bomber Command wouldn't be clearing the sky anywhere that wasn't in the immediate vicinity of their bombers. Squadrons could be transferred from one command to the other as the needs of the war progressed. The goal of this is to make it easier for Mosquito strikes on German runways to disrupt their operations vs the UK and for spitfire escorts to offer what protection they could, as long as they could and in the process start developing the pressure for a longer ranged escort fighter.

The primary avenue of cooperation with both Canada and Australia would be through coastal command as it would be the experiences of that command that would most closely reflect any encounters their own air forces would have with the enemy. Both countries would be encouraged to build both the aircraft and engines used in coastal defense. Other reasons being that these aircraft would have a much easier time self-deploying closer to the action and that the aeroengine requirements for these tended to be easier, making it less troublesome for nascent aircraft industries to produce and hopefully lay the groundwork for producing more complex and powerful engines in the future. If nothing else this would take some of the pressure off UK based engine producers and allow them to focus on the more challenging engines.

Encourage Hawker to pursue radial based fighters, both in anticipating the Hercules but also getting some assurances ( and potentially some stockpiles ) of Twin-Wasps in case of delays/problems with the Hercules. In concert with this of course encourage Bristol to push the performance as much as possible as it's no longer primarily a bomber engine.

If you can avoid taking away resources from the Mosquito encourage De Havilland to put some effort into a single engined fighter around 1940 or so as the Sabre/Centaurus/Griffon start to emerge, obviously given the size of these powerplants a similarly large plane would be recommended.

Alternatively, or as well encourage SuperMarine to do the same around the same time while keeping the cost to the Spitfire's development to a minimum.

The focus of both these projects would be to create a larger aircraft somewhat along the lines of the Tempest/P-47 that with the correct engine would be able to provide longer legged escort as well as higher altitude performance, presuming the supercharger team doesn't become a disaster.

 

[merlin]

First - Amur Tiger - welcome to the Forum, and thank you for your ideas.

Some of my thoughts:

a) - the meeting with the Wackett Mission went well, despite the jibe of 'bloody colonials' they had some interesting feedback both from their 'tour' of the Continent, and British Aero companies, and they were confident that something could be finalised shortly. The 'Mission had left with a parting request, for a report on what they found in the US to be sent to them, as well as the Australian Government.
b) - the Hendon Air Display in June, was thought to be an ideal time to meet the Aero airframe engine manufactures all together. At this meeting the Air Staff were able to impress on the 'heads of industry' there the need to expand their premises , and to expand their workforce, as future orders were going to be ten times plus what previous ones were. Even where a company's design doesn't win - the order could be that other manufactures will be co-opted, being that in mind the RAF will expect full co-operation - in that ideas to make work better are expected from everyone!!
With that 'carrot' firmly dangled, the 'stick' came out which initially caused uproar to the effect the RAF if the circumstances demanded would consider buying foreign - be it airframe or power-plants!!
c) - two Bomber spec's were issued in '36 - the first resulted in the order to Boulton-Paul P.90 - later to be named 'Barnsley', fortunately the company resisted requests to turn it into a bomber/transport. There was a design from Shorts but it was felt that it might interfere with Sunderland production - especially after the twin-engine flying boat spec R.1/36 was rescinded, Shorts were also asked to press ahead with a military version of the 'G' Class flying boat. With the second of the bomber specs issued - that as well as the large Avro Handley Page designs, to also order the smaller Bristol - to be named 'Buckfast' - to supplement the Wellington and replace the smaller twin-engine bombers Blenheim, Hampden, and Whitley.
d) - the 4 x 20mm Cannon Fighter spec - prototypes were ordered from Boulton-Paul (Dante) Westland, with the earlier Gloster twin-engine design with 2 x 20 mm + MGs. - 'Guardian'. The initial Dante flight was disappointing - because of the low powered Hercules - however the FAA seeing the opportunity, ordered a navalised version from Blackburn. The next version - had an improved performance, (here I'm being 'creative' reasoning that Bristol are worried about the RAF ordered a US engine for the Buckfast Beaufighter (instead of Hercules).
e) - rather than just one company, Vickers were also involved with adapted the HS-cannon for British manufacture and use, and with the earlier appearance of the Dante (compared with OTL cannon Spitfire) the jamming problems were solved earlier.
f) - the Austin plant was used to produce Hurricanes, after a short period of making Battles, though this needn't have a great impact on Hurricane numbers as the Gloster plant was busy with the single engine Grendell Guardian 'twin' - while their own plant also had the Henley.
g) - the Army Co-operation Command had squadrons slated for deployment to France of:- Grendalls, Hurricanes, Battles, Lysanders, Guardians, and Henleys.

 

[Shortround6]

British design staffs were not overly large and with aircraft becoming increasingly complicated, the ability of most British companies to handle more than 2 programs at the same time was rather limited. DeHavilland for example was starting initial design work on the Vampire in late 1941. Work on the Albemarle is confusing, some claim it was a Bristol design moved to A-W because of lack of design staff at Bristol and others claim it was all A_W with the competing Bristol design stopped to free up Bristol designers for other work.
Many British designs were slow to go from initial request to service use because of lack of designers/engineers. Adding more projects isn't going to help without canceling projects.

The Twin Wasp was rarely,if ever, a true substitute for the Hercules being about 150hp lower powered at best and often 300-400 hp lower in power depending on month/year.

 

[parsifal]

i agree the Twin Wasp was not really a substitute for the Hercules. It was never seriously discussed as a good enough substitute for the Beafighter by CAC. Although a problematic engine itself, Wackett had proposed using the R2600 as a substitute, including licence production of the engine. Tests were flown with the American engine installed. i dont know if those test flights were successful or not, but Wacket certainly made it sound like they were. i have doubts. anyway, further development was not required, as the supply of Hercules engines from England finally improved in 1944 and the need for an R2600 fit went away

 

[tomo pauk]

Beaufighter with R-2600s. Please note the differences in the engine installations with the plane to the right:

http://i37.photobucket.com/albums/e68/GTwiner/ca15/scan0015.jpg

 

[parsifal]

thanks tomo, any idea where and what context that photo was taken?

 

[tomo pauk]

Seems like that was an ex-Beaufighter Ic, no. A19-2 (ex T4921), Fairey-built, tested at 30 Squadron RAAF. Trials were deemed successful.
I don't have any other data.

 

[merlin]

Yes, interesting p tomo pauk - as I thought twin-wasp is a potential alternative to the Taurus and/or Mercury, whilst the R-2600 is an alternative to the Hercules.

 

[nuuumannn]

Work on the Albemarle is confusing, some claim it was a Bristol design moved to A-W because of lack of design staff at Bristol and others claim it was all A_W with the competing Bristol design stopped to free up Bristol designers for other work.

The problem is, like so many of the myths that have arisen about British aircraft, there are a number of books, including the Putnam book on Armstrong Whitworth (the authors employed by Putnam are guilty of continuing many of these myths), that state that the Albemarle was based on the Bristol 155, which was transferred to AW for continuation to B.9/38, but this is not true. The AW.41 was John Lloyd's own design. The Bristol 155 was to be built to B.17/38 and the AW.41 to B.18/38, but the requriement for an aeroplane that could be built of non strategic materials, wood and steel, which was able to be sub-contracted out to firms not proficient in aircraft manufacture (sounds a bit like the 787!), with sub sections that could be transported by the standard 60 ft Queen Mary trailer was the same. Lloyd later expressed that he had little enthusiasm for the project; the brief was for a conventional aeroplane with little novelty, but Lloyd was impressed by the nose undercarriage layout he had witnessed on aeroplanes in the USA. The Bristol 155 was designed initially as a tail dragger, but a nose u/cart variant was also drawn. It was not proceeded with. There was nothing intinsically wrong with the Albemarle, but it was never going to succeed in its intended role; it was too ordinary to be any competition to the new four engine heavies emerging in 1940/41 as a result of P.13/36 and B.12/36.

A bit more info on the pic of the Beaufighter with the Cyclones provided by Tomo; it was taken at Fisherman's Bend in 1944 (note the Beauforts in the background) and like Tomo states was a Beau Ic built at Filton, along with the RAAF's first 15 Beaufighters - T4921 was the RAAF's second Beaufighter, the other British built RAAF ones coming from Fairey. The aircraft, A19-2 was withdrawn from service with 30 Sqn (the first home based RAAF Beau unit) and sent for modification to DAP in February 1943. it first flew with the Cyclones a year later in August 1944. I'm not sure when exactly the image was taken, but I've seen another of it from the rear, showing the pointed nacelles off. It's interesting to note that it doesn't have the dihedral on its tailplanes, like the Aussie built Beaus, which were based on the Beaufighter VI, also in the picture; by August 1944, DAP had built some 14 Beaufighters, the first, A8-1 had been completed in May and was delivered in June. A19-2 went into storage in March 1946 and was presumably scrapped at Tocumwal, with most of the rest of the Beaufighters and Beauforts.

 

[tomo pauk]

The RAF and its suppliers might hopefully get some hints from friends and foes alike? Eg. earlier introduction of pressure-injection carburetor, ditto for individual exhaust stacks, maybe an introduction of small (sized like MC.200, Bf-109, Yaks) Merlin-based fighter, more fuel earlier-on on fighters (should come in handy at least in MTO and Asia/Pacific), timely copying of the cooling system of the Mustang, mine shell for the Hispano, longer air intakes (as on P-40 and P-51), adopting the P&W two-stage system to the Hercules...
After all, plenty of people were getting hints from the RAF its suppliers

I'm not going to suggest fuel injection for British engines, that is kinda taboo...

 

[KiwiBiggles]

I'm not going to suggest fuel injection for British engines, that is kinda taboo...

I don't think it was as much taboo, as just not considered overall a useful path. British engine developers were generally very keen on high boost pressures, and thought the charge cooling effect through evaporation in the inlet manifold useful enough overall to outweigh the benefits of fuel injection.

 

[tomo pauk]

I've read that many times. However:
How big was the penalty to have backfire screens installed (that fuel-injected engines did not needed, and Merlin (and V-1710) did)? How big was the manifold pressure in Bristol and Napier engines? How much and asset was a 10-15% of increased mileage/range/radius, that was available through use of fuel injection?

 

[fastmongrel]

I've read that many times. However:
How big was the penalty to have backfire screens installed (that fuel-injected engines did not needed, and Merlin (and V-1710) did)? How big was the manifold pressure in Bristol and Napier engines? How much and asset was a 10-15% of increased mileage/range/radius, that was available through use of fuel injection?

Fuel Injection requires a lot of precision manufacturing it might have been as simple as the Air Ministry making the decision that they would rather have something else made by a precision engineering company when a Carb could be made by a company making carbs for Cars and Motorbikes.

 

[Shortround6]

I am not at all sure that I want to fly in a plane equipped with Amal carburetors

However you are correct that the fuel injection system required many more (hundreds) of precision machined parts that a aircraft carburetor system. British had looked at several other Germane "devices" like the MG 151 cannon and decided that they took too much precision machine work to be worth copying.

 

[tomo pauk]

I'm sure you're right, fastmongrel. Unfortunately, it took plenty of time for the pressure injection carb to take hold in the UK (instead of the float-type carb) that is not just insensitive to negative Gs, but also improves engine performance. link
Luckily, (but not coincidentally; thanks to the designers, of course) the Merlin was outfitted with generously sized both supercharger and the carburetor's inlet, and that gave benefits for the high altitude capabilities. The later work by Hooker's team further improved the already well-founded basis.

 

[merlin]

Surprised this thread seems to be 'dying' - though pleased my earlier post didn't get 'shot-down'!

In Sept '36 Swinton made the suggestion that orders could be placed in America - Ellington was told to prepare a plan for two or three squadrons each of US Fighters and bombers, in the event of needing to increase first-line strength rapidly in the next 15 months, before the Shadow factories had any effect, yet the British Purchasing Commission was set-up until April '38. I wonder what could have been ordered earlier or as per otl but other than the Hudson, Harvard Catalina!!

Pre-war expansion Scheme were marked by letters - 'F' was from Feb '36 and was the only one of the '34-39 schemes to be completed, in late '37 the Air staff were requested to draw up a scheme which " you consider is militarily the proper insurance for safety". The result Scheme 'J' proposed a bomber force of 90 squadrons (70 in 'F'), of which 64 would be heavy and 26 medium (compared to 20 heavy 65 medium in the abortive 'H') - but it involved the mobilization of industry and it was costly! So 'J' was referred back - to make it cheaper hence 'K' of Jan '38. In Nov '38 Sir Kingsley Wood announced that Scheme 'M' planned to raise the metropolitan Air Force to 163 squadrons with an all heavy bomber command of 85 Squadrons, and Fighter Command going from 38 (of Scheme 'L') to 50 - as he said " ... to give the highest priority to strengthening of our fighter force, that force which is designed to meet the invading bomber in the air".

What can to be seen from all this upheaval of policy, is that there were opportunities to change, e.g. US equipment, perhaps the Bristol P.13/36 is disguised as a new medium bomber (two not four engines) - replaces other mediums, a replacement light-bomber - to reduce costs!
Where the challenge will be is to have a well-equipped Army Co-operation Command ready in time for continental service - something everyone seemed to be against!!

 

[tomo pauk]

Unless that Bristol is a 'proper' bomber (at least 2 Hercules, a suitable bomb bay), not overly thick wing, reasonable crew and guns number, why not? Sorta British Ju-88, but with decent internal bomb load.
Though I'd still like an unarmed bomber, starting with Merlin X engines, that can later receive Hercules for fighter-bomber and night-bomber duties. Maybe let the co-pilot (having a swiweling seat) man the rear-facing gun, so the Air Ministry has less objections to accept it.

One interesting Merlin might be useful, BTW.
The Merlin 46 and 47 have had the impeller of increased diameter installed, 10.85 in vs. 10.25 in for 'regular' (non-cropped) Merlin 45. Improved hi-alt capabilities, but at cost of the lower low-alt power. So, I'd like to see the 'big impeller' installed on 2-speed engines - so the low-alt and take off power remains competitive. Also, start installing the pressure-injection carbs on the engines ASAP, those not just completely solve the neg-G isues, but also improve engine power. Install the individual exhaust stacks. That way the Spit V should cut at half the performance disadvantage vs. Fw-190 and Bf-109F-4/G-2. Take a look at US (NACA and P&W; winter of 1941/42) experiments with individual exhausts for the radials, should give some performance boost for the radial engines machines, at least for daylight duties (where there is no need for flame dampers). Contemplate installation of wheel well covers for Spitfires (Typhoon has them, even if it is a different machine for the needs of this thread). Starting with Spitfire V, try to have the internal fuel increase by 20-30 imp gals, and by further 20-30 imp gals once more powerful engines are to be installed.
As for the USA - send several Merlin XX to the NAA (just like the Curtiss received the Merlin XX for the future P-40F) for trial installation on the Mustang as soon as possible, like second half of 1940.

 

[Shortround6]

On the exhaust thrust for radials.

R-2600

Hercules

Some engines are a lot easier to set up for exhaust thrust than others. Rearward facing exhaust ports near the outer edge of the engine may be best but may also cause the most drag, side facing ports on a V-12 are pretty good. Forward facing ports half way down the cylinder pose a few problems.