WesWorld

Shin,

I must admit the Skimmer didn't enter my head when I wrote my specs down. Had it done it would have been in the running (plus its an FAA type and so the RAF might not go for a naval type). The B.6/39 was geared towards a single-engined type but no restrictions were placed, as Capt Liptrot says the twin-engined approach looks the best. So a future requirement for a similar aircraft may well be twin-engined and may well include a Skimmer variant.

Gloster could do the work, the type would need de-navalising, new heavier cannon armament and probably a slight fuselage stretch.

A few bits on the Spiteful in this thread. Seems to come down to the increase in speed not being worth the decrease in manoeuverability and low speed handling.

The motor manufacturer Alvis has been trying to break into the aircraft engine business and despite achieving Ministry type approval the conservative Air Ministry and the powerful lobbying force of the big players (Armstrong Siddeley, Bristol and Rolls-Royce) have hampered sales but the failure of Napier to reslove problems with the Sabre and Pilates is making the Air Ministry look around.

Pelides 1,000hp 14-cyl double-row radial, poppet valve, medium supercharge, first tested 1936

Pelides Major 1,000hp, identical to the Pelides but with full supercharger, first tested 1936

Alcides 1,300hp 18-cyl double-row radial, poppet valve, medium supercharge, uses many components of Pelides and first tested in 1938

Alcides Major 1,300hp identical to the Alcides but with full supercharger, tested 1938

Alcides 1,800hp 18-cyl double-row radial with two-speed full supercharger and developed from Alcides, hopefully tests to begin soon with possible production ready late 1940/early 1941

Maeonides Major 650hp 14-cyl double-row radial, poppet valve with single-speed full supercharger, tested 1937

9ARS (Leonides) 450hp 9-cyl single-row radial, poppet valve, single-speed medium supercharger and Zenith carburettor, hopefully tests to begin 1940.

Nice news piece but....

....I don´t understand the rational behind the Maeonides Major 650hp 14-cyl double-row radial.

Why build a complex and expensive two-row 14 cylinder engine when you can get the same power output from a 7 or 9 cylinder engine?!

Quoted

Originally posted by HoOmAn
Nice news piece but....

....I don´t understand the rational behind the Maeonides Major 650hp 14-cyl double-row radial.

Why build a complex and expensive two-row 14 cylinder engine when you can get the same power output from a 7 or 9 cylinder engine?!

Who knows, but it was proposed in real life. I guess it could offer a smoother power distribution, but that's all that springs to mind.

I thought that odd too. Perhaps the author of the book I'm using got the wrong end of the stick or the records were wrong. A single-row radial would seem more logical. Also there is no basic Maeonides listed which implies Alvis were just offering a full supercharger variant rather than a medium-power supercharger.

Don't know how these would work, the Pelides passed bench testing but never flew, Pelides Major flew on a two-seat Bulldog and the 9ARS became the postwar Leonides which certainly was successful. Would be nice to think Alvis could have some luck in WW.

I'm slowly updating my engines and stats and so keep eyes peeled here for more info as it arrives.

Quoted

Originally posted by Hood
Would be nice to think Alvis could have some luck in WW.

Luck doesn't have that much to do with it. Alvis made aircraft engines (well really only the Leonidas) that worked and that's about it. They were a small company, with little aviation expertise, and most interest in cars. It's difficult to see any of the other engines being particularly successful. Simply building numbers might be a big enough problem.

The 14 cylinder engine gives a nice small diameter, useful for smaller applications or for reducing drag.

Well most of the Alvis engines were on paper only so we can only speculate as to their success. The big players stifled Lord Nuffield's attempt to enter the small aero engine market post war. They have big sticks to bash the car motor makers.

Really I haven't any aircraft that need these engines just yet (although the 1,300 and 1,800hp engines might be useful as a back-up to the Hercules) but someone might order some in WW. After all Gothia Works and many other non-OTL firms seem adept at building world beating engines don't they?

Quoted

Originally posted by Hood
Really I haven't any aircraft that need these engines just yet (although the 1,300 and 1,800hp engines might be useful as a back-up to the Hercules) but someone might order some in WW. After all Gothia Works and many other non-OTL firms seem adept at building world beating engines don't they?

Well yes, but ordering a bunch of engines into production just because it would be nice doesn't make much sense and wastes lots of money. We seem to be re-arming and spending money on military stuff at an even faster rate than the 1930s. Can't possibly afford to do that in the long term. Little point in most of those Alvis engines as the Pegasus and Hercules already fit the bill. There's a gap at lower power levels, which is why the Leonidas was more successful (and the greater technical risk in the higher power engines).

An extract from J.G. Vincent's 'Fairey Monarch - Forsyth's Wonder Engine' Aero Press 1954

"C.R. Fairey in 1923 imported fifty Curtiss 465hp D-12A engines without Air Ministry approval and installed them in his new Fairey Fox light bomber which outpaced every fighter the RAF had at the time. The Curtiss D-12 revolutionised Rolls-Royce and many other aero makers in the country. However it also made C.R. Fairey enemies at the Air Ministry and Rolls-Royce.

In 1931 Captain A. Graham Forsyth, a former RFC pilot and responsible for liquid-cooled engine development policy at the Ministry, joined Fairey as Chief Engine designer. His first engine, the 650/670hp Prince V-12 engine and the supercharged 900hp Prince II had successful bench trials and flight trials but no production or offical support was forthcoming.

Graham Forsyth then turned to another idea, a vertical H engine in which each vertically-opposed half would drive a seperate unit of a contra-rotating propeller unit. This would give twin-engine reliability and much improved endurance as one half of the engine could be shut down while cruising. Work began in 1932 and two designs emerged. The first was a 16-cylinder H engine producing around 1,500hp as the Prince 3. The other would become the definitive 24-cylinder Monarch of 2,240hp but ultimately to be capable of achieving 3,200hp.

The Prince 3 flew in a modified Fairey Battle in 1938 and successfully completed basic trials but from an early stage the focus was on the P.24 Monarch. Fairey Battle K9370 first took off powered by the Monarch in October 1938 and between June-July 1939 undertook a civil test of 50 hours without incident. Eventually another 120 hours would be flown before the Battle was handed over to RAE Farnborough. Before then another 50 hours of bench trials had been acomplished and the RAE would use another Monarch in a wind tunnel to study contra-rotating propeller effects at take-off power for 15 hours. Again without problems. By the end of 1939 another Battle was fitted with a Monarch.

The Air Ministry was still not supporting the development fully and Rolls-Royce and Napier pointed towards thier Vulture and Sabre engines currently under production. The Air Ministry however was concerned over the problems both engines were having with the Vulture maturing but the Sabre still needing serious work on the sleeve-valves with the assistance of Bristol's Roy Fedden. It was the Admiralty via the Fleet Air Arm that pushed the development of the Monarch. They could see much potential in the P.24 for long-range naval applications and by the end of 1939 the Air Ministry was forced to spend a modest amount to aid Farey (C.R. Fairey would ultimatley put in £100,000 of his own money). The FAA could see potential use to solve many of its own powerplant problems;

Avro Canada (Gloster) SS.40 Skipper: One P.24 could provide all the power neccessary with sutiable gearing and reduce weight over two Merlins.
Fairey Firefly: a P.24 could have superior power over the Griffon for comapable weight and also give the single-engined fighter twin-engine safety albeit at the expense of more frontal area.
Fairey Barracuda: underpowered with the Merlin and the Griffon still unready the Barracuda could be boosted to 350mph with a P.24 with twin-engine like safety. The extra power would boost take-off performance from smaller flightdecks.
Short S.25 Sunderland: the H-16 Prince 3 would be ideal in giving the Sudnerland in effect eight engines and the ability to cruise for extended periods with the engines partially closed down
Blackburn B.20 Boston: the Vulture was still a problem affecting this fast flying boat type, the Prince 3 or the Monarch could provide even more dash speed while giving additional safety and cruise economy.
Supermarine 328 Southport: developed to R.5/35 this could be a true fast flying boat with the Monarch

The applications seemed many but already by early 1940 problems began to surface. The advertised four-speed single-stage supercharger was not developed, each 'half' of the H had its own two-speed supercharger. Concerns were raised over crankshaft vibration and strength concerns over the crankcase (the P.24 was 500lbs lighter than the equivelent Sabre engine), the lack of damping springs on the crankshaft and the added complication of contra-rotating propellers (at the time still novel). Fuel consumption was only average and height performance was not as good as the Merlin, an engine much smaller in capacity. Even more important was the fact that Fairey had no production facility of its own and no established firm would take on the work. The idea to use the engine on fighters was looking less and less likely but the Admiralty still clung to the main idea to use the engine on its carrier-based bombers and RAF long-range patrol bombers. It was even touted as an engine for the Bristol 'Ideal Bomber' and even on the Avro Lancaster to make it a two-engined type and so reducing drag. Then the Air Ministry had doubts over its safety claims saying that if the main crankshaft (each side drove two crankshafts, one inside the other) or the oil system suffered a failure then both halves would be inoperable. Secretly Rolls-Royce began considering a similar engine using two Merlin V-12s.

By the end of 1940 Graham Forsyth had redesigned the vibration absorbion on the crankshaft and strengthened the casing at a cost of 200lbs. Battle K9370 began trials with the revised Monarch in September 1940 as discussions were made about an eventual production site and finding additional investment from outside the Ministry."

The headline stats of Fairey's engines look good but when you read into it a bit more they didn't work too well and just weren't very strong.

Rolls-Royce's twin Merlin is snuggled away at the back here with a vertical 24H configuration. Big bore Vulture is a lot easier way to get a 24cylinder Merlin. The ultimate engine would probably be the RR Eagle scaled down a bit. Lots of very nice bits of technology in that engine, and they worked as well.