Can we make a slightly smaller Fulmar as an improved carrier fighter?

[Admiral Beez]

At some point in 1941 it had been determined that all Rolls-Royce projects would be cancelled, except for the Merlin, Griffon and Crecy.

Don't forget the Derwent. In 1941 Rolls-Royce took over this engine from Rover.

 

[z42]

So they could concentrate on 2 main engines instead of 3.

Yes, but crucially also the 2 main RR engines that ended up contributing to the war were poppet valve V-12's. The winning recipe was to take a solid, but in no way exotic (even "boring" if you will), base engine and laser focus on improving it via supercharging, intercooling, pressurized cooling, (much too late but still) fuel injection / pressure carburetor, etc. And of course making the basic engine sturdier to handle the higher power asked from it.

Of course, the availability of high octane gasoline was instrumental in keeping the comparatively small 27L Merlin competitive until the end of the war.

 

[wuzak]

Don't forget the Derwent. In 1941 Rolls-Royce took over this engine from Rover.

Was it not 1943?

 

[z42]

Don't forget the Derwent.

Sure, though I think it was implied we were talking about piston engines here. Jets excepted, as it was clear jets were the future, and as a new technology much more varied experimentation was warranted to find the promising paths to focus on and develop further.

 

[wuzak]

Yes, but crucially also the 2 main RR engines that ended up contributing to the war were poppet valve V-12's.

And the 2 engines that could fit into the Spitfire!

 

[wuzak]

There is support for RR wanting out of Vulture development from as early as Aug 1939 here.

Rolls-Royce Vulture X-24 Aircraft Engine

Developed in the late 1930s, the Rolls-Royce Vulture X-24 was rushed through development and into service. As a result, the Vulture proved unreliable and was cancelled in favor of other aircraft en…

oldmachinepress.com

But the Air Ministry wanted it to go on. Work finally stopped Oct 1941.

My point being that the Vulture was closer to being a reliable 2,000hp+ engine than the Monarch was.

 

[z42]

My point being that the Vulture was closer to being a reliable 2,000hp+ engine than the Monarch was.

If we look at which British piston aero engines actually achieved 2000+hp in service during the war, that's the Sabre, the Griffon, and, well, that's it?

Had RR not put the Griffon project on hold, and instead never started the Vulture, Exe, Pennine, Eagle, and Crecy projects, and instead put those man-hours into the Griffon, maybe the 2000+ hp Griffon would have been available already mid-war?

 

[Shortround6]

Had RR not put the Griffon project on hold, and instead never started the Vulture, Exe, Pennine, Eagle, and Crecy projects, and instead put those man-hours into the Griffon, maybe the 2000+ hp Griffon would have been available already mid-war?

Define mid-war.
The Griffon needed 18lbs of boost to hit 2000hp.
So you need a supercharger that can deliver than amount of air at 18lbs boost and you need fuel that work at 18lbs of boost.
Test engines and service engines are bit different.

The Problem in 1939-41 was that nobody knew if either thing was possible on a practical level, so you needed bigger engines than the Griffon (or you needed more RPM)

 

[Wild_Bill_Kelso]

it seems like better superchargers would be a good avenue for improvement for a lot of the earlier, smaller engines, if nothing else to provide power at higher altitudes.

 

[Wild_Bill_Kelso]

There is a manual for the SBD-3 from 1941, However it seems that they changed the max gross weight after than manual was printed.
The Manual gives fuel capacities for both unprotected tanks and protected tanks. With protected tanks the fuel capacity was as high at 260 US gallons, unprotected was 310 gallons.
Bombloads came out of the fuel allowance which is why they changed the max gross weight.
The 1200hp engines don't show up until SBD-5 and that is over a year after they were putting the same engines in F2A-3s and some Hawk 75s.
The SBD-6 got about the same engine as the FM-2. Maybe they changed magnetos something.

The SBDs got the higher gross weight, it didn't shorten the take-off run with more fuel and the same size bomb.

Can you share some more details from the SBD-3 manual? It's hard to find data on other than SBD-5

 

[Wild_Bill_Kelso]

I like the Skua. Imagine if after it was removed from the fleet if four or five squadrons of Skuas were transferred to Ceylon in time to join the Blenheims on their unopposed strike on Nagumo's fleet.

yeah I'm not so sure, but maybe they would have hit something. Those Blenheims did eventually get spotted and attacked, though it came a little late and I think only by a couple of Zeros. They were very lucky they didn't lose more.

 

[Wild_Bill_Kelso]

There were a few advantages that the Fulmar had over the Sea Hurricane or other normal land based fighters of the time.

The 4 hour endurance meant few take-offs and landings per day for the same amount of CAP coverage (fight hours) and this is even better than a simple 4 is twice as good as 2 calculation. The CAP (or recon planes) need to arrive at the carrier around 30 minutes before landing (roughly) to allow for navigation errors, carrier getting turned into the wind and so on, then provide for accidents. If the first plane in the queue crashes while landing how long does it take to clear the deck and the other planes can land without running out of fuel?
You don't get a 2 hour CAP mission out of a land plane that has a 2 hour nominal endurance.

Fulmars could, at times, investigate more contacts or conduct more interceptions before needing to land than shorter endurance planes could. Same for the ammo. The extra ammo capacity allowed for more engagements.

The goal is try to get a plane with more speed/climb than the Fulmar while keeping the endurance (or most of it) and keeping close to same trigger time.
However with the same engines that were available at any given point in time something has to give. Take a Spitfire from 1940, add 100lbs for a folding wing, add 100lbs for more ammo and add even 400lbs of fuel (55Imp Gal) and you are about 10% heavier than a shore based Spit ( haven't added dingy, hook and more radio gear), if you are are OK with that fine. But you are are not going to get land based Spitfire performance.

That may be OK (and the 1941 Version with Merlin 45 does get better)

It just seems that trying to cut down a nearly 10,000lb plane to 7-8,000lbs seems to be a round about way of getting to what is wanted.

All of that is fair. I was leaning toward a cleaned up / trimmed down Fulmar because A) the aircraft worked B) it seems like it might take less time than a new design, and C) it seems like it could have been possible. Spitfire is a bit small for a carrier fighter especially if you have armor, SS tanks and more fuel. But it is certainly possible that a longer ranged Spitfire could have been built, and as it was so much better streamlined it should be consistently faster for the same power. Give either one of them a merlin XX.

 

[Wild_Bill_Kelso]

Between June 1940 & May 1941 the RN fought aggressively in the Med taking the fight to the Axis at every opportunity. The passage of convoys was used as a reason for both Force H and the Med Fleet to go out and hit the enemy throughout the Med & Aegean Seas. And a decent sized torpedo carrying Swordfish force was required in case the Italian Fleet came out to play as well as providing ASW protection to the fleet.

It's very different operating in the Med, or close to shore in Norway, versus the open Atlantic. Submarines are still a threat in all WW2 environments but if you know you are going to be passing close to land based strike aircraft (and even close enough to be engaged by land based interceptors) then more fighters in the mix is really important. As was made clear by the disastrous outcomes for so many convoys.

 

[Wild_Bill_Kelso]

No, you want mostly ASW for convoy work. The British lost far more warships and merchant losses to U-Boat attack than by air attack.

I would say that depends very, very much how close you were going to pass to enemy bases, especially if you were going to pass in range of Stukas. Or in the case of theoretical Pacific operations, anywhere near Japanese carriers.

List of Royal Navy losses in World War II - Wikipedia

en.wikipedia.org

Merchant Navy Losses WWII

List of all Merchant Navy ships lost due to enemy action during World War II.

www.battleships-cruisers.co.uk

We still need to keep the bombers away. I'd make it 60:40 TSRs to Fighters.

If you are going to be passing near Sicily or Crete, I'd say 80 /20 fighters.

The problem is the CAGs are too small. Click on any carrier to see, Aircraft Carrier database of the Fleet Air Arm Archive 1939-1945 Contents Page

I agree with that but you need more fighters, IIRC the USN made the same decision.

 

[Shortround6]

Part of the problem is when.

As and when France fell Britain went into panic mode. They shut down a lot of R&D and concentrated on building what was already in production, even if it wasn't very good.
As far as fighters actually went they were producing around 2 Hurricanes for every Spitfire. This went up and down a bit but Castle Bromwich was running late and then Southampton got bombed just under 3 months later so things were a little dicey. Shutting down a production line and loosing several months production to convert to something else took a lot of arguing. Heck they needed hordes of Lysanders for ground cooperation for all the Army divisions they were trying to rebuild
It had taken several years just to get the Fulmar into production. Cancel the Fulmar and the FAA would be stuck with Gladiators, Skuas and Rocs for even longer.
It was taking the British too long to get new aircraft into production, just about everything was running late.

Your best bet/s are to modify an existing aircraft the least amount possible and accept that you are not going to get what is actually wanted.
This assumes Britain survives the German sea borne invasion. A few people in the British Gov should have had a bit more faith in the RN (and be able to count past 11 without taking their shoes off).

Until the situation eases up somewhat and the Seafire can be worked on the next best thing is a proper Sea Hurricane. Not RAF machines on the borderline of being condemned from further land use. Not as good in a fight as a Seafire but better than a Roc (low bar indeed) or Gladiator.

So what can be done without changing things too much?
Fitting a simple folding wing? Just enough to get the plane down through the lift. Worry about compact hanger storage later.
Cut the armament to 4 guns?

Take out the inner two guns and ammo and put in a fuel tank on each side.
Maybe put one gun out board where the MK IIb carried two?
For low altitude work use the Merlin VIII engine as used in the Fulmar? All you need is a different supercharger gear.

The Hurricane I was the single engine plane that was being produced in the greatest numbers per month in 1940. You know it can both take off and land on carriers after April of 1940. Not as well as desired but it was done which puts it ahead of testing anything else (carrier trials with turretless Defiant take place when?)

 

[Shortround6]

I would say that depends very, very much how close you were going to pass to enemy bases, especially if you were going to pass in range of Stukas. Or in the case of theoretical Pacific operations, anywhere near Japanese carriers.

Worry about Japan from mid 1941 on.
Until the Japanese expand into French Indo-China concentrate on the Med.

 

[Thumpalumpacus]

It's very different operating in the Med, or close to shore in Norway, versus the open Atlantic. Submarines are still a threat in all WW2 environments but if you know you are going to be passing close to land based strike aircraft (and even close enough to be engaged by land based interceptors) then more fighters in the mix is really important. As was made clear by the disastrous outcomes for so many convoys.

This was also the conclusion of the USN in 1942 in the Pacific: 18 fighters wasn't enough for the job.

ETA: Just saw that you already got there.

 

[Wild_Bill_Kelso]

On 8 May 1941 Fulmars from Ark Royal and Formidable engaged both the Luftwaffe and Reggia Aeronautica and soundly thrashed them both:

RA losses:

4 x SM79
2 x CR42

Luftwaffe losses:
1 x Ju-88
4 x He-111
2 x Me-110 (crash landed due to battle damage)
1 x Me110 damaged
(1 x Ju-87 confirmed by Fulmar gun camera but not noted in Luftwaffe records)
1 x Ju87 damaged

FAA:

2 x Fulmar (one from bomber defensive fire)
2 X Fulmar crash landed on CVs
1X Fulmar crashed due to weather (not combat related)
6 x Fulmars damaged

Data from Shores, Mediterranean Air War, 1940-1945: Volume One: North Africa, June 1940-January 1942, p182-185

As usual from your posts, the most optimistic possible interpretation of the best cherry picked day possible.

I can't believe this is necessary again, but I'll go through the obvious data.

At Ceylon, the British had 67 Hurricanes, 44 Fulmars, and 14 Blenheims, 12 Swordfish, and 7 PBYs. They lost 16 Hurricanes, 6 Swordfish, 4 Blenheims and 4 Fulmars and just about every ship in the area, for 4 D3A "Vals" and 2 A6M2. The radar didn't detect the Japanese aircraft either by the way.

At Pedestal there were 72 carrier fighters (16 Fulmars and 6 Hurricanes on Victorious, 10 Martlets, 24 Sea Hurricanes and 14 Albacores on Indominatble, and 16 Sea Hurricanes on Eagle), plus multiple land based fighters including 100 Spitfire Vs and 36 Beaufighters on Malta, as well as several other bombers.

Four torpedos fired by U-73 hit Eagle and sunk it on the morning of 11 August, taking with it 16 fighters. That left the fleet with a total of 56 fighters (46 servicable) of which 16 were Fulmars.

Fulmars and Sea Hurricanes were unable to catch 'snooping' Ju 88s early in the morning on 12 August. They then shot down 5 out of 19 Ju 88s from the first raid (which was good!). Around noon, Sea Hurricanes and Fulmars failed to intercept two large Italian raids and another German strike and Victorious was hit twice but only lightly damaged, plus one ship (Deucalion) was hit and crippled. 3 Axis bombers and 1 fighter were lost to AA.

An Italian submarine (Giada) was attacked by a Sunderland and damaged but managed to shoot it down. Another submarine was sunk by a British destroyer.

Later in the early evening Fulmars were able to shoot down an SM. 79 snooper, but could not catch a Cant Z1007 which was also following the convoy (though they did detect it). This led to another Italian raid of SM.79s and Stukas escorted by fighters (from Pantelleria) which was intercepted by 3 Martlets, 12 Sea Hurricanes and 3 Fulmars. One Italian Ju 87 was shot down by the fighters and one by AA. Rodney was damaged by a near miss, Indominatable was hit by two 2,200 lb bombs from stukas and damaged by three near misses, setting it on fire and heavily damaging the flight deck (thus ending air operations and resulting in several planes having to be pushed into the Sea from Victiorious later). Ships coming to the aid of Indomitable were then attacked by SM. 79s and Foresight was hit by a torpedo and scuttled the next day.

This left the fleet with 21 fighters - 8 Sea Hurricanes, 3 Martlets, and 10 Fulmars.

Up to this point the Axis lost 18 aircraft (vs 39 claimed) mostly to AA, while the fleet lost 7 fighters (3 Fulmars, 3 Sea Hurricanes, and 1 Martlet shot down)

A CAP of 4 Fulmars that evening was apparently driven off by Bf 109s with one lost and one badly damaged. They were then attacked again by He 111s carrying torpedoes and Bf 110s. Four of the cargo ships were hit, with Clan Freguson and Empire Hope sunk. Another (Manchester) was sunk by a submarine.

On the morning of 13 August the Convoy was hit again. By this point they were in range of the large numbers of land based fighters at Malta but they did not seem to play much of a role initially, so convoy defense was up to their 21 remaining carrier borne fighters.

Sadly they were also in range of the Bf 109s, Bf 110s and MC 202s which escorted the Ju 87s and Ju 88s on several raids. It is unclear if CAP even intercepted these raids. Ohio and Waimarama were hit, with the latter exploding. Dorset was then hit and abandoned. The first morning attacks lost two Ju 87s and one Bf 109. Another attack by SM.79s escorted by MC 202s hit a merchant ship with one toropedo but it was a dud.

A second wave of attacks in the afternoon was partly intercepted by Spitfires from Malta. One group of Ju 87s hit and sunk the crippled Dorset, but another wave of 18 Ju 88s turned back in the face of Spitfires. Brisbane Star was hit twice by SM. 79s but the torpedoes were duds. Charbydis shot down two SM 79s which attacked it. A large force of 35 Ju 88 and 13 Ju 87 bombers attacked the fleet again, but got only one near miss and lost a Ju 88 and a Stuka. Another cargo ship, Foresight, damaged in previous attacks, sunk.

Outcome of Pedestal
Total losses were 48 Axis aircraft, out of 285 bombers participating at some point in the battle. British lost 34 aircraft, an aircraft carrier, 3 warships (2 CLs and 1 DD) 9 merchant ships sunk, and another aircraft carrier badly damaged.

Many of the attacks were unescorted, and carried out by 1930s vintage Italian aircraft like CANT 1007, SM.79 and CR.42 biplanes. Others were by faster Ju 88s which seemed to often evade the Fulmars and Sea Hurricanes, and the slow but very lethal Ju 87s. I don't know why more Ju 87s weren't intercepted.

Sea Hurricanes and Fulmars repeatedly failed to drive off snooper aircraft such as Z. 1007 and SM.79, as well as faster Ju 88s. They did not seem to manage to turn back any of the raids, in fact several raids seem not to have been intercepted at all, and most raids suffered quite low losses, compared to similar battles in the Pacific*.

It is notable that Spitfires, on the last day, did drive off at least one wave of attacks by Ju 88s and scored several victories.

It's clear that submarines were a big threat the whole time, but these were mostly dealt with by destroyers and land based aircraft or seaplanes (Sunderlands).

It also seems to me that FAA combat air patrols were too small. And of course, the aircraft capacity of the carriers was too low. I would have left the 14 Albacores at home by the way for this one.

I think better fighters could and should have been able to intercept most of the 'snoopers' and most of the raids, should have imposed higher losses on the Axis bombers, especially when unescorted, and particularly the slower Ju 87s and Italian bombers, and should have turned back some of the raids. Seafires probably would have, though their limited range and endurance would mean relatively small CAP flights and more launching and recovery time.

This is why I see the need for an aircraft with better performance than the Fulmar or Sea Hurricane, and better endurance than a Seafire.

* for example - Battle of Coral Sea, IJN lost 97 out of 139 aircraft. Battle of the Eastern Solmons, IJN lost 75 out of 171 aircraft. Battle of Santa Cruz Islands, IJN lost 99 out of 199 aircraft.

 

[Thumpalumpacus]

It should be noted that USN Wildcats were often not able to catch and shoot down snoopers. There are more factors that go into it: altitude, cloud cover, fuel states, etc.

 

[z42]

Define mid-war.

Well, let's (optimistically?) say that by not putting Griffon on hold and canceling those other projects, Griffon could be introduced into service 18-24 months earlier than historically.

The Griffon needed 18lbs of boost to hit 2000hp.
So you need a supercharger that can deliver than amount of air at 18lbs boost and you need fuel that work at 18lbs of boost.
Test engines and service engines are bit different.

For S/C development, true, that's one thing I'd hope could be brought in sooner with my suggested changes.

As for fuel, IIUIC Griffon was cleared for 18lbs with 100 octane fuel. Not sure whether that was the 100 octane that was in use by the BoB, or the slightly later 100/130(?) which it seems was often also called "100 octane".

Late in the war Griffon was cleared for 21 or 25 lbs, but that required the late war 150 octane fuel.

The Problem in 1939-41 was that nobody knew if either thing was possible on a practical level, so you needed bigger engines than the Griffon (or you needed more RPM)

That's true, and of course with the information they had at the time canceling all those other projects wouldn't have made sense, as they couldn't have known how quickly turbine technology would develop.

However, arguably putting Griffon on hold was a mistake, as that was clearly the lowest risk project for delivering more power than the Merlin.