Fulmar in 1941/42/43: feasible and/or plausible upgrades?

[RCAFson]

The chart seems a little bit off. IF I am using the cube law correctly the FUlmar "III" should be good for 291mph at 12,000ft using your assumptions. Since people seem to want to turn the the Fulmar into a higher altitude fighter let's also look at 20,000ft.
Just about all official charts show the speed at altitude falling off in a curve, not a straight line. And even if the Fulmar did to 240mph at 20,000ft ( which rather shows how hopeless things were to begin with as on test a Gladiator did 239.5mph at 20,000ft) the difference in power between the the Merlin 30 and the 45 gets narrower with altitude. The 45 has a good margin but the difference in speed will not be simply moving the Fulmar II line over to correspond to the peak power point a 12,000ft.
Going by the TOmo's chart and having 6000 meters equal 20,000ft. it appears that the Merlin 30 was good for 850hp (give or take) and the Merlin 45 was good for 1100 hp (give or take). The Merlin 45 had 37.7% (?) more power at 12,000ft but at 20,000ft it has 29.4% (?) more power. Ussing the cube law and the 240mph speed at 20,000 ft we wind up with a speed of 261mph at 20,000ft not 273-5mph.

Perhaps minor quibbles but then the Martlet chart is for the Martlet IV which was the worst performing Martlet/Wildcat built (used the same engine as most American Brewster Buffaloes). Granted the UK got about 220 of them but at anywhere above 13,000ft it is going to be about 10-15mph faster than a Fulmar "III".

And that is part of the big picture, Any other Martlet/Wildcat is going to be 20-40mph faster than the Fulmar "III" above the Merlin 45's 16lb boost critical altitude.

Now what is the performance of a Sea Hurricane?

Adding an extra ~130 hp at 6800 ft gives the Fulmar another ~13 mph of performance. At 12000ft adding another ~115hp should do the same.

The lines above FTH should be curves, but the effect of this would be to slightly raise speeds above FTH to the last data point on the graph. The Fulmar II performance at 20,000 feet was a data point taken from official test results. The Fulmar's reliance on low altitude rated engines greatly handicapped it at higher altitudes but the Merlin 45, for example, was static rated for 1230hp/16000ft/9lb boost/2850rpm. At 3000 rpm it could hold 9lb boost to ~18000ft and this is substantially better than the XXX which would down to 3 or 4 lb of boost at 18000ft. The Merlin XX would probably give superior high altitude performance compared to the Martlet IV.

The F4F-4B performed very close to the F4F-4 under 15000ft, and most FAA combat was under this altitude, however increasing Fulmar performance above 15000ft would have allowed for more successful intercepts of high altitude recon aircraft and give a better climb rate for better diving intercepts.

 

[RCAFson]

Data sheet says:
308 mph at 18,000 feet (+ 6.25 boost)
315 mph at 7,500 feet (+ 16 boost)

Merlin III/eight-Browning version (only Sea Hurricane sheet available).

Thanks!

Say what weights are given and what is the ammo load out?

 

[Greyman]

330 rounds per gun

weights (no tanks or bombs)
max - 7,015 lb
mean - 6,655 lb
light - 6,100 lb
tare - 5,344 lb

Speeds are supposedly with 'mean' weight, but take this with a grain of salt, I've seen this be untrue on some sheets, based on A&AEE tests

 

[RCAFson]

330 rounds per gun

weights (no tanks or bombs)
max - 7,015 lb
mean - 6,655 lb
light - 6,100 lb
tare - 5,344 lb

Speeds are supposedly with 'mean' weight, but take this with a grain of salt, I've seen this be untrue on some sheets, based on A&AEE tests

Thanks again!

One last thing, what was the climb rates?

 

[Greyman]

10.0 minutes to 20,000 feet at max weight

 

[RCAFson]

10.0 minutes to 20,000 feet at max weight

Does it give a combat climb rating?

This is really interesting stuff.

 

[Greyman]

That's all its got for climb data unfortunately.

 

[Mike Williams]

What to say - many thanks Mike, maybe it's time to give space at your site for the Defiants, Fulmars and Fireflies

Hi Tomo, I'm happy to contribute and I'm glad you found it useful. Good idea on Defiants, Fulmars and Fireflies! We'll see what we can do...

 

[Shortround6]

The Merlin III in the Sea Hurricane (only) was approved for 16lbs boost. At this level of boost it gave 1440hp at 5500ft.

When this was done, I don't know (Wiki says for Operation Pedestal in Aug 1942) and how expendable the engines/aircraft were considered I also don't know. The ones flown off of CAM ships were pretty much one flight operations. Trashing the engine was probably not high on the list of concerns.

I am not sure if this engine was ever approved for higher than the "normal" 2600rpm/6 1/4lb boost climb.

The window of opportunity for an "improved" Fulmar seems to be AFTER the RAF gets the Spitfire V in some numbers ( and or gets satisfied that the MK II Hurricane isn't REALLY going to be a front line fighter and can free up some MK XX engines) AND after the boost limit is raised to at least 12lbs for such engines. AND Before Sea Hurricanes are available in any numbers.

Something to consider on the 12lb vs 16lb limit is how much was engine strength/engine life and how much was fuel limited. I don't know when the British got large stocks of 100/130 fuel. The British 100 octane during the BoB was NOT 100/130. It was 100/115-120 depending on the batch. It was AFTER the BoB that the performance number scale (anything over 100 octane) was established and fuel could be specified and tested to the new standard. In the US some Allison engines were being rated on 100/125 fuel in 1941. Exactly When the British and Americans standardized on 100/130 fuel seems to be little noted. I have read that the allowable formulations for 100/130 were changed in early 1943 which is part (only one part) of what lead to the P-38 Allison problem in Europe but this was anticipated and work begun on a new intake manifold in the spring/summer of 1943 for the "new" 100/130 fuel as compared to the "old" 100/130 fuel.

Martlet Vs with two stage engines started to be supplied to the RN in Dec 1942 (in small numbers) which rather puts paid to any notion of using any sort of Fulmar past then.

 

[RCAFson]

Here's the performance chart with the Sea Hurricane 1B added, using my best guess to the performance curve in between Greyman's data points. I have also added the curves for a hypothetical Sea Hurricane/M45 with 16lb boost. It should give a slight increase in performance over the MIII even at the MIII FTH because of the superior SC on the M45:

I don't agree that the Martlet V could fully replace the Fulmar because the Fulmar still has a very useful advantage in recon capability and can act as a DB, but historically these capabilities were never used to their full potential because RN CVs were only briefly active in the IO/Pacific in 1942/43. Also the measured performance of the F4F-4 (Martlet V) never came close to it's SAC/FAA data card figures, at least in 1942, and it compared very poorly with the Zero in terms of level performance, during USN/USAAF comparative trials.

 

[Shortround6]

I don't agree that the Martlet V could fully replace the Fulmar because the Fulmar still has a very useful advantage in recon capability and can act as a DB, but historically these capabilities were never used to their full potential because RN CVs were only briefly active in the IO/Pacific in 1942/43. Also the measured performance of the F4F-4 (Martlet V) never came close to it's SAC/FAA data card figures, at least in 1942, and it compared very poorly with the Zero in terms of level performance, during USN/USAAF comparative trials.

What does "never came close to it'sSAC/FAA data card figures" Mean?

In the test report that you quoted before it has an F4F-4 doing 316mph at 17,200ft. Now this may NOT be "close" to the 332mph some times claimed but on the other hand it is just about equal to the Firefly I. It is marginally faster than a Sea Hurricane I with a Merlin III, It is about 20mph faster than the Martlet IV and almost 35mph faster than your proposed Fulmar III. If the F4F-4 isn't fast enough then were does that leave the rest of these planes?

 

[RCAFson]

What does "never came close to it's SAC/FAA data card figures" Mean?

In the test report that you quoted before it has an F4F-4 doing 316mph at 17,200ft. Now this may NOT be "close" to the 332mph some times claimed but on the other hand it is just about equal to the Firefly I. It is marginally faster than a Sea Hurricane I with a Merlin III, It is about 20mph faster than the Martlet IV and almost 35mph faster than your proposed Fulmar III. If the F4F-4 isn't fast enough then were does that leave the rest of these planes?

Actual trials showed the F4F-4 to be slower than the SAC data but also to have a much poorer climb rate, which made it barely superior to the Fulmar when both use normal climb power and probably worse when military/combat power was used, and this in turn limited its ability to act as an interceptor. I've already quoted part of a comparative trial showing the F4F-4 being outperformed by the F4F-4B at low altitude, and in turn the F4F-4B is greatly outperformed by the Sea Hurricane and Firefly especially under 12,000 ft where most naval fighter combat took place. The Firefly 1 is generally faster than the F4F-4, outclimbs it, has far more firepower, and both it and the Sea Hurricane can outturn the F4F. The Firefly can also act as a long range escort, naval strike fighter, and long range recon aircraft. In 1942 the Firefly would have been a very potent aircraft. Also, a two seat fighter always has an inherent advantage in combat in terms of visibility because the pilot has someone else to help locate and track the opposition.

 

[Aozora]

Also, a two seat fighter always has an inherent advantage in combat in terms of visibility because the pilot has someone else to help locate and track the opposition.

Doesn't help much having extra eyes when all that extra weight needed to carry those extra eyes reduces speed and manouverability while making the entire aircraft into a bigger target. The reason fighter formations were devised was to provide extra eyes and mutual support. The rear seat eyes in the Fulmar didn't even have a peashooter with which to provide some slight protection/support for the pilot.

Why the FAA persisted with a two-seat fighter when the other two carrier forces got purpose-built single seat fighters is a mystery wrapped up in a riddle, but has a great deal with the RAF's obsession with making the FAA use multi-role aircraft as an economy measure (the RAF controlled the FAA until 1939).

 

[RCAFson]

Doesn't help much having extra eyes when all that extra weight needed to carry those extra eyes reduces speed and manouverability while making the entire aircraft into a bigger target. The reason fighter formations were devised was to provide extra eyes and mutual support. The rear seat eyes in the Fulmar didn't even have a peashooter with which to provide some slight protection/support for the pilot.

Why the FAA persisted with a two-seat fighter when the other two carrier forces got purpose-built single seat fighters is a mystery wrapped up in a riddle, but has a great deal with the RAF's obsession with making the FAA use multi-role aircraft as an economy measure (the RAF controlled the FAA until 1939).

By the end of WW2 the USN had come around to the FAA position of having only two primary CV based aircraft; a multi-purpose strike fighter and a multipurpose recon-DB-TB as evidenced by the aircraft complement of the armoured flight deck Midway class CVs. Under RN control, the FAA planned, by 1942, to equip it's carriers with two primary aircraft, the multipurpose recon-strike fighter Fairey Firefly and the multipurpose recon-DB-TB-ASW Fairey Barracuda. Such a combination would have been completely competitive, if not superior to the 1942 IJN and USN in terms of capability. It was the BofB and the consequent disruption in FAA aircraft development that prevented this plan from reaching fruition.

The Firefly 1 with 230 usg was slightly lighter (12250lb) than the F6F-3 with 250 usg (12500lb). In 1942 the Firefly would have been a winner, but even in 44/45 it was still a capable recon-strike fighter that, with its F-Y flaps, could out-turn a Zero.

 

[Juha]

By the end of WW2 the USN had come around to the FAA position of having only two primary CV based aircraft; a multi-purpose strike fighter and a multipurpose recon-DB-TB as evidenced by the aircraft complement of the armoured flight deck Midway class CVs. Under RN control, the FAA planned, by 1942, to equip it's carriers with two primary aircraft, the multipurpose recon-strike fighter Fairey Firefly and the multipurpose recon-DB-TB-ASW Fairey Barracuda. Such a combination would have been completely competitive, if not superior to the 1942 IJN and USN in terms of capability. It was the BofB and the consequent disruption in FAA aircraft development that prevented this plan from reaching fruition.

The Firefly 1 with 230 usg was slightly lighter (12250lb) than the F6F-3 with 250 usg (12500lb). In 1942 the Firefly would have been a winner, but even in 44/45 it was still a capable recon-strike fighter that, with its F-Y flaps, could out-turn a Zero.

Why RN still needed Seafires, Hellcats and Corsairs? They needed something to protect their CVs and their strike a/c. So much on the 2 multi-role a/c concept.

 

[RCAFson]

Why RN still needed Seafires, Hellcats and Corsairs? They needed something to protect their CVs and their strike a/c. So much on the 2 multi-role a/c concept.

None of the above was available in any numbers before 1943, and I didn't claim that the Firefly was competitive as a pure fighter/interceptor after mid 1943.

With it's upgraded engines and cooling systems, the Firefly F4 would have been competitive with the Hellcat, had it appeared a couple of years sooner, as it wasn't the 2nd crew member that cut it's performance so much as the underdeveloped state of the Griffon engine and the RAF having priority for them.

 

[wuzak]

Oh! I do like to fly in a fast Seafire
I do like to fly over the sea!
I do like to climb then turn, turn, turn!
And make the Hun's planes
Burnity-burn-burn-burn
So just let me fly in a fast Seafire
I'll be beside myself with glee

 

[Aozora]

By the end of WW2 the USN had come around to the FAA position of having only two primary CV based aircraft; a multi-purpose strike fighter and a multipurpose recon-DB-TB as evidenced by the aircraft complement of the armoured flight deck Midway class CVs.

That's an over-simplification of the American position because it ignores the use of the F8F as a pure fighter and the obsolescence of the dive bomber as a concept. And note that the Americans were not interested in having a two-seat single-engine strike fighter because they chose to utilise the F4U complemented and later supplanted by the AD Skyraider in the strike role. Until the late 1950s American carrier-borne fighters were rarely two-seaters. It could be argued that even in the 21st century the USN continues to rely on single-seat multi-role strike aircraft in the form of the F/A-18E series which, incidentally, partly replaced the two-seat F-14.

Under RN control, the FAA planned, by 1942, to equip it's carriers with two primary aircraft, the multipurpose recon-strike fighter Fairey Firefly and the multipurpose recon-DB-TB-ASW Fairey Barracuda. Such a combination would have been completely competitive, if not superior to the 1942 IJN and USN in terms of capability. It was the BofB and the consequent disruption in FAA aircraft development that prevented this plan from reaching fruition.

Where did you get this idea? There was a requirement for a turret fighter under N. 9/39 - which resulted in the useless Blackburn Roc. The FAA also wanted a single-seat fighter and were offered a Sea-Spitfire in 1938, plus there were plans for a single seat fighter under N.11/40, which eventually resulted in the Blackburn Firebrand - an aircraft which only became a "strike fighter" because it was useless at anything else; the plans for a Sea-Spitfire with folding wings came to naught because, as mentioned elsewhere, Dick Fairey absolutely refused to allow his factories to build anything other than Fairey designs.

There is absolutely no evidence that a Firefly/Barracuda combination would have been superior to the IJN or USN - that's an assumption on your part.

The concept of continuing with a two-seat fighter in 1942 was wasteful of resources when it had been proven that single-seat, single engine fighters were more than useful, and it should be noted that no more specifications were issued for two-seat naval fighters after 1940.

In 1942 the Firefly would have been a winner, but even in 44/45 it was still a capable recon-strike fighter that, with its F-Y flaps, could out-turn a Zero.

The Firefly would have been even better and more useful in 1942 as a smaller aircraft without the back seat - it might have even truly been a winner. Useful in 1944/45, sure but essential, no.

 

[nuuumannn]

Under RN control, the FAA planned, by 1942, to equip it's carriers with two primary aircraft, the multipurpose recon-strike fighter Fairey Firefly and the multipurpose recon-DB-TB-ASW Fairey Barracuda.

Do you have any evidence to back this up? Where does the order for Grumman Martlets fit into this? What about the Blackburn Firebrand, built to N.11/40 raised to cover the type as a single-seat fighter with a minimum top speed of 403 mph? There is more than enough evidence presented here in this thread that the Admiralty wanted high performance single-seat fighters.

Of interest, owing to delays in the Firebrand programme, the Admiralty examined the prospect of a Sea Typhoon, the P.1009 that was to be built to N.11/40 instead. A Sea Tempest was considered in 1942, but was rejected as the Seafire, the aeroplane the Admiralty had been requesting for a few years was in service.

 

[RCAFson]

Do you have any evidence to back this up? Where does the order for Grumman Martlets fit into this? What about the Blackburn Firebrand, built to N.11/40 raised to cover the type as a single-seat fighter with a minimum top speed of 403 mph? There is more than enough evidence presented here in this thread that the Admiralty wanted high performance single-seat fighters.

Of interest, owing to delays in the Firebrand programme, the Admiralty examined the prospect of a Sea Typhoon, the P.1009 that was to be built to N.11/40 instead. A Sea Tempest was considered in 1942, but was rejected as the Seafire, the aeroplane the Admiralty had been requesting for a few years was in service.

The wiki article on the Firebrand states that it was originally intended for fleet base defence, but I have no doubt that the FAA was actively exploring long range options for SS fighters, in response to foreign developments but this doesn't alter the fundamental priority placed on the two seat fighter. The development of useful long range AW seaborne radar also undercut the need for two seat fighter (radar/IFF could act as a homing device) but in 1939 this was unknowable.

The GSG, Martlet, HSH and SSF were all emergency responses to the contemporary situation where the FAA found itself at war prematurely, and then had it's own development and procurement plans delayed by the FofF, BofB and the general crisis which ensued following the Commonwealth finding itself alone against the Axis.

We can see the FAA/RN doctrine in action during 1940/41 when the typical complement of RN fleet CVs was the DB/TB Swordfish/Albacore and the recon/fighter Fulmar. Technically the Fulmar was also a strike fighter but this capability was delayed until late in it's career although it was in the Admiralty specs. The development of both the Firefly and Barracuda were delayed but if they had entered service as planned then instead of the interim Fulmar/Abacore the FAA would have fielded the Firefly/Barracuda as their sole carrier borne aircraft, and in 1942 this combination generally outperformed the IJN/USN equivalents and in <1940>the Fulmar/Albacore actually compared well with foreign carrier borne aircraft.

If the Firefly had been coming into service in 1942 then both the HSH and Martlet would have been superfluous, as neither (especially the Martlet) has enough of a performance/range or firepower edge over the Firefly to make them worthwhile.

The development and specs for the Barracuda and Firefly were driven by Admiralty/FAA requirements not limitations imposed by the RAF and any reading of their design and development will show that this was so. For example the RAF was doctrinally opposed to DBs, yet the FAA fielded 3 TB/DBs (Swordfish/Albacore/Barracuda) and 3 DB/strike Fighters (Skua, Fulmar, Firefly) and it was the Admiralty that pushed for this:

...From about 1933 on, the Admiralty showed increasing interest in dive-bombing, as the best means of accurate delivery against small and highly manoeuvrable ships. Dive-bombing was also particularly attractive as a means of neutralizing enemy aircraft carriers, which some in the Fleet Air Arm considered their primary targets. British observers seem to have been impressed by US demonstrations...Friedman, British Carrier Aviation, p.156