A better FAA twin seat, single engine fighter for 1940?

[wuzak]

Have Rolls Royce produce about 800-1000(?) of a 'derated' version of the 'R'. The Fulmar has a large enough airframe that it could handle the weight and size of the engine, despite the added length of the 'R' engine over the Merlin - CG and w&l could be dealt with fairly easily. On 100 grade fuel it would have a continuous power rating (2850 rpm at +9 lbs) of ~1900 BHP at 9,000 ft. Military (3000 rpm at +9 lbs) would be ~2000 BHP at 10,000 ft. Note that this is for the 'R' with a 7.47 SC gear ratio.

Rolls-Royce did test a detuned R as the Griffon I (~1933). Its performance was not great, and it was abandoned.

I can't see how a detuned racing engine from the late 1920s/early 1930s would be able to have continuous power greater than the maximum power of the Griffon II using the same fuel.

I'm not sure that the higher maximum rpm (3,000 vs 2,850 for the Griffon) would be sustainable.

 

[ThomasP]

Hey wuzak,

Griffon 58 1-stage/2-speed, 2450 BHP at 2750 rpm at +25 lb boost at SL . I cite the Griffon 58 here even though it is a late-war model because it is the only Griffon at +25 lb boost on 150 grade that I could find authoritative ratings for.

2450 BHP x (3000 rpm / 2750 rpm) x (39.7 / 29.7) = 2000 BHP at SL

NOTE We are running at higher rpm than the Griffon (as you mentioned above) so the IHP will increase ~proportionately and the HP absorbed by the S/C will also increase, but we are running at 10 lb less boost which will decrease the HP absorbed by the S/C by a significantly greater amount. Since I was starting work in 1936 based on the original 'R', I assumed that the 1941 efficiency of the S/C would be comparable to the 'Hookerized' Merlin as both engines would have been developed in parallel during the same time frame. I figured there would be some inefficiencies involved so I did not push it to +25 lb of the actual Griffons when rated on actual 150 grade.

This is what the notional developed 'R' maximum power curve at 3000 rpm (no ram) looks like:

__Alt_____BHP____Boost
30,000___1060____- 4.0 lb
25,000___1270____- 0.7
20,000___1500____+2.2
15,000___1760____+5.7
10,000___2055____+9.6
_5,000___2380___+14.1
_4,000___2450___+15.0 FTH
SL______ 2375___+15.0_____2000____+9.0

And this is what the notional developed 'R' maximum power curve at 2850 rpm (no ram) looks like:

__Alt_____BHP____Boost
30,000____960____- 4.0 lb
25,000___1140____- 1.7
20,000___1350____+1.0
15,000___1585____+4.1
10,000___1845____+7.7
_5,000___2140___+11.9
_1,600___2360___+15.0 FTH
SL______ 2320___+15.0_____1900____+9.0

All the results above were derived using Hooker's mathematics from the RR Trust 'The Performance of a Supercharged Aero Engine'.

edit: Sorry, typos again. The SL BHP values for +15 lbs boost are now correct. I really have to stop posting so late at night.

 

[Admiral Beez]

And change the Skua's ridiculous cockpit windscreen. I'm no aerodynamicist, but c'mon, that "forward swept" barn door windshield can't possibly help.

Agreed. I believe the near-vertical windscreen was for enhanced view of the target, but IDK. The Fulmar has two advantages over the Skua, speed and range. If we can put the Merlin onto the Skua and clean up the aerodynamics a little we might exceed the Fulmar's speed. Range will be trickier.

 

[nuuumannn]

Forgive what might seem dumb questions.

Nah mate, you're on the right track. No questions are dumb, it's usually the unthought out answers that tend to be!

 

[Admiral Beez]

That the Air Ministry didn't instigate a single-seater is always blamed on the navy, but it wanted them. There was definitely a disconnect between operational experience and what was being decided in the Air Ministry for the FAA in the 1930s, but there was a reason for it. Carrier deck space was limited and in the early 30s, fearing a size and weight increase in modern aircraft decisions were made that meant that dual role aircraft were gonna be incorporated on carriers, so the likes of the Skua and Fulmar were ordered. The other issue was cost versus predicting where the next threat might come from, the former being an ever-present issue in peacetime and the latter in that the British didn't anticipate the Germans would invade Europe again so soon after the Great War. Even before the Skua entered service it was criticised by senior admirals as being inadequate for their needs. The Hurricane was of interest and by the mid-1930s was being discussed as a future carrier single-seat fighter.

It would have been interesting to see the changes in RN and FAA procurement and ops planning had the Japanese carrier fleet been seen as a strong threat. Here's what's building in the UK and Japan through to end 1938, the end of which when Japan is invading China and US and British sanctions are beginning to bite.

HMS Illustrious, laid down Apr 1937
HMS Victorious, laid down May 1937
HMS Formidable, laid down Jun 1937
HMS Indomitable, laid down Nov 1937
HMS Ark Royal, commissioned Dec 1938

IJNS Hiryu, launched Nov 1937
IJNS Shokaku, laid down Dec 1937
IJNS Soryu, commissioned Dec 1937
IJNS Zuikaku, laid down May 1938
IJNS Akagi, reconstruction and comm Aug 1938

Clearly there was something afoot in the PTO that Britain could have paid some attention to, for example, what fighters and strike aircraft is the IJNAS using in this period. Had Britain considered that in addition to facing German and possibly Italian strikes, that it may need to fight the IJN's carrier forces at sea, the FAA, RN and AM might have made different decisions on aircraft.

 

[Thumpalumpacus]

It would have been interesting to see the changes in RN and FAA procurement and ops planning had the Japanese carrier fleet been seen as a strong threat. Here's what's building in the UK and Japan through to end 1938, the end of which when Japan is invading China and US and British sanctions are beginning to bite.

HMS Illustrious, laid down Apr 1937
HMS Victorious, laid down May 1937
HMS Formidable, laid down Jun 1937
HMS Indomitable, laid down Nov 1937
HMS Ark Royal, commissioned Dec 1938

IJNS Hiryu, launched Nov 1937
IJNS Shokaku, laid down Dec 1937
IJNS Soryu, commissioned Dec 1937
IJNS Zuikaku, laid down May 1938
IJNS Akagi, reconstruction and comm Aug 1938

Clearly there was something afoot in the PTO that Britain could have paid some attention to, for example, what fighters and strike aircraft is the IJNAS using in this period. Had Britain considered that in addition to facing German and possibly Italian strikes, that it may need to fight the IJN's carrier forces at sea, the FAA, RN and AM might have made different decisions on aircraft.

Agreed. Not only would better aircraft defend against the more-present danger of German/Italian maritime air, but perhaps have given the FAA something more to work with against the Japanese. However, getting those planes into the theater would have require at least one more fleet carrier (with adequate escort), don't you think?

Given their wartimes straits, I simply don't think the UK had that sort of ability to project power. All the more reason to equip their carriers with better fighters.

 

[Admiral Beez]

However, getting those planes into the theater would have require at least one more fleet carrier (with adequate escort), don't you think?

They weren't great due to slow ROF, but IIRC the Brits had one of the first dedicated AA cruiser escorts in the Dido class.

My dream team RN CBG for the PTO, three Illustrious class (even with Fulmars, if we must), Hood and two Renowns with much enhanced AA, a half dozen Dido AA cruisers, plus destroyers. And fleet oilers. But yes, once things go sideways in Europe there's no way to project power in the PTO.

But including plans to deal with Japan during the FAA development and planning phases would go a long way to better aircraft for the ETO and MTO.

 

[Thumpalumpacus]

My dream team RN CBG for the PTO, three Illustrious class (even with Fulmars, if we must), Hood and two Renowns with much enhanced AA, a half dozen Dido AA cruisers, plus destroyers. And fleet oilers.

You're gonna need a bigger navy.

 

[Admiral Beez]

You're gonna need a bigger navy.

Sadly true. Britain should have begun construction of the Illustrious class as soon as the naval treaties allow.

 

[Shortround6]

Clearly there was something afoot in the PTO that Britain could have paid some attention to, for example, what fighters and strike aircraft is the IJNAS using in this period.

The Akagi when she joined the fleet in late 1938/early 1939 was equipped with
12 Claude's. (+5 spares)

19 Suzie Dive bombers (+5 spares)

and 35 Yokosuka B4Y "Jean" torpedo bombers. (+19 spares?)

She operated off of South China at the Beginning of 1939 and off central China in the spring of 1940.

The Kaga's air group at the end of 1940 consisted of
" 12 Mitsubishi A5M fighters, 24 Aichi D1A dive bombers and 36 Yokosuka B4Y torpedo bombers. Another 18 aircraft were carried in crates as spares "

So what were the Japanese aircraft in 1937-38 that the British should have been taken note of?

 

[Thumpalumpacus]

Sadly true. Britain should have begun construction of the Illustrious class as soon as the naval treaties allow.

There's that. But there's in addition to funding those ships (and their escorts) the cost of developing the new FAA fighter itself, while the Army is wanting new tanks and the RAF wants their own new fighter designs, and 4-engined bombers are also being planned but not yet paid-for.

We're gonna need a bigger budget ... in the 30s.

 

[Shortround6]

Ship design was constantly evolving. as was propulsion technology.

A carrier designed in 1933-4 and laid down in 1935 is going to be a poorer ship than one designed in 1936-36 and laid down in 1937.

 

[swampyankee]

Trying to get back to the original topic....

Given the constraints on size, power, and stall speed needed for operation on RN carriers and the demands for range, radio range, and endurance, I'm not sure that there could have been much improvement.

Even given that, I think two things could have been done:
1) I think the fuselage could have been shortened by about 3 feet. This would save some weight and reduce wetted area.
2) While airfoil thickness isn't that closely related to drag coefficient, even at that time, there were somewhat better airfoils than the NACA 4-digit series.

 

[swampyankee]

There's that. But there's in addition to funding those ships (and their escorts) the cost of developing the new FAA fighter itself, while the Army is wanting new tanks and the RAF wants their own new fighter designs, and 4-engined bombers are also being planned but not yet paid-for.

We're gonna need a bigger budget ... in the 30s.

For different reasons, neither the Tories nor Labour were willing to increase defense spending.

 

[fastmongrel]

Ark Royal was designed with the Indian and Pacific Ocean theatres in mind. I think the plan for a war with Japan was Ark, Courageous and Glorious would form the fleet with the battlecruiser squadron as escort.

 

[ThomasP]

What I have read is that there were original intentions to build 5 Ark Royals (or the Ark Royal and 4 improved Ark Royals) for general purpose fleet carriers, and I have read what fastmongrel mentions above about operating in the Indian/Pacific Ocean theaters.. The Ark Royals (originally designed for 72 airframes stowed) would have been kind of a compromise between modern large air group carriers like the Japanese and US were building, and the smaller air group armoured deck carriers of the Illustrious class (designed for 36 stowed airframes). The RN had already studied deck parks pre-1935 and had a pretty good idea of what would need to be done to use deck parks, and what the increase in effective air group size would be. The Ark Royal was completed with provision and intent to fit 1 or more crash barriers, as was every later fleet and light fleet carrier built.

But the focus of the build-up changed after the 1935-36 London Naval Conference, when Japan withdrew from the Treaty - and when it was already apparent that Germany was rebuilding its armed forces. The Admiralty decided it needed to focus on the potential North Atlantic/Mediterranean theaters.

I have also read that as far as funding for naval ship building goes, there was no shortage of funds from about 1936. The problem was actually ship yard building slip availability. Apparently the UK's shipbuilding industry had shrunk so much post-WWI that it was almost impossible for them to build/rebuild/heavily-modify ships any faster.

 

[nuuumannn]

They weren't great due to slow ROF, but IIRC the Brits had one of the first dedicated AA cruiser escorts in the Dido class.

The Didos were cool looking ships, the RNZN had a couple in service after the war as the last of its big cruisers - the New Zealand navy has never operated a class of combat ship larger than a medium-sized cruiser, the Indefatigable Class battlecruiser HMS New Zealand was bought by the Dominion but donated to the Grand Fleet and there wasn't such a thing as a New Zealand navy at the time. The New Zealand only visited the country twice in its career. It did take part in Jutland however, but I digress...

 

[nuuumannn]

I have also read that as far as funding for naval ship building goes, there was no shortage of funds from about 1936. The problem was actually ship yard building slip availability. Apparently the UK's shipbuilding industry had shrunk so much post-WWI that it was almost impossible for them to build/rebuild/heavily-modify ships any faster.

Correct. Obviously, during peacetime, it's always difficult to go ahead with military expansion plans, but the political climate did dictate that it was necessary from 1937 - 1938 onwards. Dockyards were a problem for Britain; most of its docks were built in the previous century and even earlier. Here is the Chatham dock, where HMS Victory was built. Victory was a First Rate Ship-of-the-Line and a powerful vessel, but the dock isn't that big. That's a WW2 destroyer in there. It has been modified since, but was essentially the same dimensions as the existing space.

2107 Chatham Historic Dockyard HMS Cavalier

2107 Chatham Historic Dockyard Old Single Dock

The navy faced this problem prior to the Great War after the completion of the Dreadnought as the rest of the world wanted them but didn't have the facilities to build them, so started from scratch. Britain didn't have the facilities for a naval arms race either but had to continue with one that arguably it had instigated, so it had to make do with what it had and modify it to suit, whereas its direct competition, the Kaiser's navy built new facilities.

 

[Shortround6]

A number of the big navies had to modify building programs to suit available slipways/docks.

Sometimes it was question of larger numbers of smaller ships as they could only build so many larger ones at one time. Sometimes building yards could expanded and sometimes they couldn't, or at least not easily. Some yards could expand sideways (add extra building slips side by side with existing ones) but getting longer slips was sometimes blocked by other property or obstacles. Sometimes a yard was limited to length of the ships it could build by the width of the river/body of water it was on. Launching hull only to have stern run aground on the opposite bank

Not hull size but some yards had cranes of limited capacity, yes you can build install new cranes but if a dozen yards are all clamoring for new cranes at the same time?

 

[Admiral Beez]

The navy faced this problem prior to the Great War after the completion of the Dreadnought as the rest of the world wanted them but didn't have the facilities to build them, so started from scratch.

Good points, though Britain's yards were churning out large ships. No other nation other than the US laid down seven carriers and five battleships from 1937 to 1939. All with UK defence spending up to 1939 staying below 5% of GDP (compared to close to 50% in Japan from 1938).

It's noteworthy that no battleship or carrier was laid down in 1938. I expect all the large yards had to clear its slips before starting new projects. This speaks to nuuumannn bottle neck. In a perfect system the last three carriers, including the RN's first maintenance CV would have been laid down in early 1938 rather than 1939.