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

[Admiral Beez]

At the end of the day, isn't the Firefly a smaller, albeit still with two seats, Fulmar?

Firefly

• Length: 37 ft 11 in (11.56 m)
• Wingspan: 41 ft 2 in (12.55 m)
• Wing area: 330 sq ft (31 m2)

Fulmar

• Length: 40 ft 2 in (12.24 m)
• Wingspan: 46 ft 4.25 in (14.1288 m)
• Wing area: 342 sq ft (31.8 m2)

 

[wuzak]

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?

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

When is this "hold"?

Note that the Griffon I, based on the R, which was based on the Buzzard, has very little to do with the Griffon II, which was started ~1938.

There was a delay when the Griffon was slightly redesigned so that it could fit into a Spitfire (originally being intended for carrier aircraft) and during 1940, where maximum effort was put into the Merlin.

To clarify, the Griffon that appeared in WW2 was started after the Vulture, Peregrine, and Crecy, the Crecy largely being a research project.

The Eagle and Pennine projects were started around 1943.

 

[wuzak]

They ended up using the knowledge gained with the 'R' to aid in the development of the later-Kestrel and Peregrin/Merlin/Griffon series.

The Kestrel preceded the R.

The R was based on the Buzzard, which was based on a 6/5 scale of the Kestrel.

 

[wuzak]

First run 1943. But AIUI in 1941 RR took over the Derwent project. So, in 1941, RR had four aero engines in production or development: Merlin, Griffon, Crecy and Derwent.

Eventually, in early 1943, Spencer Wilks of Rover met Hives and Hooker for a dinner at the Swan & Royal Hotel, Clitheroe. By mutual agreement between the Minister of Aircraft Production and the Boards of Rover and Rolls-Royce, the Rover jet factory at Barnoldswick was exchanged for the Rolls-Royce Meteor tank engine factory in Nottingham. A handshake sealed the deal.

Rolls-Royce Welland - Wikipedia

en.wikipedia.org

There were 2 engines Rolls-Royce took over - the Wellend (W.2B/23) and Derwent (W.2B/26).

 

[nuuumannn]

I really don't give a rats ass if you like what I post.

Well, that says it all, doesn't it. A rather self-centred attitude you have in refusing to consider what others have to say. Again, let the adults do the talking.

 

[nuuumannn]

I really don't give a rats ass if you like what I post.

Well, that says it all, doesn't it. A rather self-centred attitude you have. Again, let the adults talk.

 

[z42]

When is this "hold"?

From wikipedia: "Design work on the Griffon started in 1938 at the request of the Fleet Air Arm, for use in new aircraft designs such as the Fairey Firefly. In 1939 it was also decided that the engine could be adapted for use in the Spitfire. Development was stopped temporarily to concentrate efforts on the smaller Merlin and the 24-cylinder Vulture; the engine did not go into production until the early 1940s. "

 

[z42]

While RR has been puttering around with modified R engine(s). The "official" Griffon I development didn't start until '38, 1st run at end of Nov, '39 and tossed in recycle bin 4/Dec/'39 for the clean sheet Griffon II.

Z z42
If you're wanting mass produced Griffon I, you're getting engine that doesn't fit in Spitfire, and is 'only' good for 1,750hp max. as like Merlin I, it is designed around the limits of 87 octane fuel.

Griffon II, in addition to much better packaging, and is running a much more efficient supercharger.

Oh, yes, I absolutely want the Griffon II, sorry if that was unclear. Just saying that if they had the Griffon as the #2 priority after the Merlin all along instead of flailing around with various wild concepts that in the end weren't successful, they could have reached the point where they toss out Griffon I and replace it with Griffon II earlier, and then no hiatus in the development of that one. If they'd had done that, I don't think it's unrealistic the Griffon II could have been introduced into service much earlier than it was historically (say, a year or two?).

Also, isn't the Vulture supercharger the starting point for the 1st stage of the two stage Merlin?

Butterfly effect of pulling some things in/cancelling others has unintended consequences.

Yes, butterfly effects are always a problem with such what-if scenarios, and also they tend be designed with the benefit of hindsight, as indeed my scenario also suffers from. And there are of course an infinite number of different alternative scenarios to consider, why was this particular one chosen etc. So what-if scenario tend to be of limited utility for serious historical scholarship. But I'm not here as a professional historian (though I'm very grateful we have such ones on the forum who are willing to part with their hard-earned wisdom!), I'm just shooting the breeze about a topic I find strangely fascinating as a hobby, so I find myself less constrained in contemplating various ahistorical scenarios.

 

[z42]

There was probably no law in the British legal system that deals with piston speeds


British indeed have had better materials. I'm okay with 2700 rpm on the British 603.

2700 sounds optimistic.

For comparison, Merlin was running at 3000 rpm for a MPS of 15.2 m/s, and Griffon was running at 2750 for a MPS of 15.4 m/s. And Griffon had 1.37 times larger volume than the Merlin. So if we design a V-12 Griffon follow-up with 1.37 times larger volume than the Griffon we end up at 51L. Both Merlin and Griffon had a bore/stroke ratio of about 0.9. So a 51L V-12 with a bore/stroke ratio of 0.9 means we have a stroke of 188mm and a bore of 170mm. If we want to keep the same MPS as the Griffon and Merlin we're limited to 2450 rpm.

 

[Admiral Beez]

I just call it like I see it. I really don't give a rats ass if you like what I post.

Brother, just use the ignore function to remove unproductive posters from your feed. I call it the contrarian filter. It can make your forum experience and discussions a lot more enjoyable and counterintuitively, more informative.

 

[EwenS]

At the end of the day, isn't the Firefly a smaller, albeit still with two seats, Fulmar?

Firefly

• Length: 37 ft 11 in (11.56 m)
• Wingspan: 41 ft 2 in (12.55 m)
• Wing area: 330 sq ft (31 m2)

Fulmar

• Length: 40 ft 2 in (12.24 m)
• Wingspan: 46 ft 4.25 in (14.1288 m)
• Wing area: 342 sq ft (31.8 m2)

Totally different designs by two different designers but with a passing family resemblance coming as they did from the same stable. H E Chaplin who had joined the design staff at Fairey in 1930 was appointed Chief Designer in 1940 in succcession to Marcel Lobelle, said this about the Firefly design:-

"I reviewed the the specifications and the design work done previous to my appointment [on N.8/39 & N.9/39 designs previously submitted by Fairey], put them all on one side and set out afresh to design the best aircraft I could within the limitations of the specification."

Two things allowed the Firefly to have a smaller wing than the Fulmar:-

1. Take off and landing criteria set down in the Specs which had been relaxed a bit.

O.8/38 for the Fulmar specified a stalling speed not to exceed 56 knots and take off distance of 225 ft against a 20 knot headwind
This was relaxed in the original N.8/39 & N.9/39 Specs to 58 knots and 300ft respectively.
Then in Spec 5/40/F, which was the one that led directly to the Firefly, there was a further amendment to 68 knots and 300ft

2. The Firefly was fitted with Fairey-Youngman flaps which had the effect of increasing the wing area when deployed for take off and landing.

Chaplin's previous project at Fairey had been the FC.1 airliner cancelled in the run up to WW2

 

[SaparotRob]

Nice looking airplane.

 

[tomo pauk]

2700 sounds optimistic.

Not for 1943 for service use.
3000 rpm for 1945.

For comparison, Merlin was running at 3000 rpm for a MPS of 15.2 m/s, and Griffon was running at 2750 for a MPS of 15.4 m/s. And Griffon had 1.37 times larger volume than the Merlin. So if we design a V-12 Griffon follow-up with 1.37 times larger volume than the Griffon we end up at 51L. Both Merlin and Griffon had a bore/stroke ratio of about 0.9. So a 51L V-12 with a bore/stroke ratio of 0.9 means we have a stroke of 188mm and a bore of 170mm. If we want to keep the same MPS as the Griffon and Merlin we're limited to 2450 rpm.

51L engine that turns 2450 rpm looks fine; granted, we'd be going into Vulture weight & size class with this engine. Not that it is a deal breaker, just it limits the airframe types it can be installed on.
OTOH, I have no desire to keep the same MPS as it was the case with Griffon and Merlin. Eg. Jumo 213 was turning extra 500 rpm vs. Griffon, despite the bore being in ballpark, and extra 950 rpm was to be used by the 213J (yes, it is 1945 now).

 

[Wild_Bill_Kelso]

Makes for 215 imp gals.
A Spitfire with a 90 gal drop tank carries 174 imp gals total. Tuck in another 20 gals and there is no advantage for Fulmar since it was heavier and draggier, so it will use more fuel both in combat and away.
Hurricane with 2x45 gals in DTs = ~185 imp gals? The Mk.II was rated for both 2x45 and 2x90 gals.

yeah but that is a little bit misleading. The problem is that neither the Spitfire nor the Hurricane can fight with 90 gallons (let alone 180 gallons) of external fuel can fight with that fuel onboard. Too much of the fuel in this case is in the external tanks, which by the way, make them 'heavier and draggier' - especially in the case of one of those 90 gallon slipper tanks!

Carrier ops are probably going to be a challenge too.

And the Fulmar, in this case, is carrying a lot less but in theory it too could have been plumbed for a couple of 45 Imp gallon, or 75 or 80 gallon wing tanks.

If just sticking a couple of external tanks on a Spitfire, or if a Hurricane could even do the job, then the RN wouldn't have openly acknowledged that they had a problem with the range and endurance limitations of the Seafire. They certainly wouldn't have needed or wanted any Corsairs or Hellcats.

 

[Wild_Bill_Kelso]

At the end of the day, isn't the Firefly a smaller, albeit still with two seats, Fulmar?

Firefly

• Length: 37 ft 11 in (11.56 m)
• Wingspan: 41 ft 2 in (12.55 m)
• Wing area: 330 sq ft (31 m2)

Fulmar

• Length: 40 ft 2 in (12.24 m)
• Wingspan: 46 ft 4.25 in (14.1288 m)
• Wing area: 342 sq ft (31.8 m2)

Yes, clearly, and yet still a bit too big and heavy IMO. But it does show the path forward, and that they realized those wings were too big. I think the wingspan was fine for the Firefly, probably, but it still had too much wing area. And too much other odd bits. They should have been able to make a smaller, lighter, better streamlined single-crew fighter as well.

 

[wuzak]

From wikipedia: "Design work on the Griffon started in 1938 at the request of the Fleet Air Arm, for use in new aircraft designs such as the Fairey Firefly. In 1939 it was also decided that the engine could be adapted for use in the Spitfire. Development was stopped temporarily to concentrate efforts on the smaller Merlin and the 24-cylinder Vulture; the engine did not go into production until the early 1940s. "

They also had to redesign parts of the engine so that it could fit in the Spitfire.

If the work was delayed in late 1939, say around September, it makes sense, particularly in relation to the Merlin.

 

[EwenS]

Carrier ops are probably going to be a challenge too.

90 Imp Gal drop tanks worked just fine for the FAA Saefire III off Jpan July/Aug 1945

 

[Wild_Bill_Kelso]

Totally different designs by two different designers but with a passing family resemblance coming as they did from the same stable. H E Chaplin who had joined the design staff at Fairey in 1930 was appointed Chief Designer in 1940 in succcession to Marcel Lobelle, said this about the Firefly design:-

"I reviewed the the specifications and the design work done previous to my appointment [on N.8/39 & N.9/39 designs previously submitted by Fairey], put them all on one side and set out afresh to design the best aircraft I could within the limitations of the specification."

Two things allowed the Firefly to have a smaller wing than the Fulmar:-

1. Take off and landing criteria set down in the Specs which had been relaxed a bit.

O.8/38 for the Fulmar specified a stalling speed not to exceed 56 knots and take off distance of 225 ft against a 20 knot headwind
This was relaxed in the original N.8/39 & N.9/39 Specs to 58 knots and 300ft respectively.
Then in Spec 5/40/F, which was the one that led directly to the Firefly, there was a further amendment to 68 knots and 300ft

2. The Firefly was fitted with Fairey-Youngman flaps which had the effect of increasing the wing area when deployed for take off and landing.

Chaplin's previous project at Fairey had been the FC.1 airliner cancelled in the run up to WW2
View attachment 745313

All good points, clearly the specs were a big part of the problem with the Fulmar, from the beginning. The takeoff and landing restrictions were probably due at least in part to the small size of the early RN carriers.

But I think the requirements for landing speed were too low, while the weight was too high (probably due to other requirements, including the second crewman with all his associated kit). I don't think they needed the Fairey Youngman flaps (which add a lot of drag).

F6F-3 Hellcat 4,190 kg empty / 5,554 kg 'gross' / 6,992 kg max .... top speed 371 mph, range 945 miles, takeoff distance 335', takeoff speed 86 mph, power on stall speed 79.5 mph
F4U-4 Corsair 4,238 kg empty / 6,654 kg 'gross' / 6,592 kg max .... top speed 393 mph, range 1,005 miles
Firefly Mk. 4,388 kg empty / 6,114 kg 'gross' / 7,083 kg max ... top speed 316 mph*, range 775 miles,

One crewman and a bit cleaner wings and fuselage would probably give you a much better performing fighter. They did manage to boost the speed a lot in later versions.

*367-386 mph speed for the latest, post-war versions
** according to armoured carriers

Firefly could carry two 45 or 90 gallon drop tanks extending the range to 1,088 or 1364 miles respectively, per "Armored carriers". Though this reduced top speed to 207 / 204 mph

Hellcat and Corsair could also carry large external tanks to increase range. Both Hellcat and Corsair got faster with later marks and higher boost / water injection etc. Corsair a lot faster.

Climb was best for the Corsair, by far. Early F4U-1 climbed at 2,890 fpm, they got this to 3,000 - 3,300 fpm by 1944, but the F4U-4 with the four blade prop climbed like a rocket. This document says 4,770 fpm initial climb, and 4.9 minutes to 20,000 ft, which is better thant I expected. Hellcat climb rate was intiially about 2,200 - 2,500 fpm initial, which is pretty bad. Later models improved that a good bit to 3,000 - 3,600 fpm.

All I could find on the Firefly's rate of climb (from Armouredcarriers) was 2.5 minutes to 5,000 ft and 5.75 minutes to 10,000 ft. Which works out to about 2,000 fpm initial.

Clearly the design emphasis here was on range rather than performance, but the Corsair, smallest and slimmest of the three, was not only faster but had better range. And the late models (was F4U-4 even in the war?) proved that even a big bruiser of a plane like a Corsair could also be a very fast interceptor that could climb like a rocket in a pinch.

Now this is much harder with the smaller engines, as Shortround pointed out. Lets look at the smaller ones next - F4F-3, F4F-4, FM-2, Sea Hurricane, Seafire III, Seafire XIV, Fulmar, A6M2 and A6M5

 

[Wild_Bill_Kelso]

Well, that says it all, doesn't it. A rather self-centred attitude you have. Again, let the adults talk.

Look mate, we don't know each other from Adam. You get a bit fussy here and there, but I've got nothing against you. I'm just not going to get bent out of shape if you are (as far as I can tell, irrationally) mad about something I posted. If you want to have an adult conversation, which I think most of the rest are doing, by all means join in.

 

[Wild_Bill_Kelso]

90 Imp Gal drop tanks worked just fine for the FAA Saefire III off Jpan July/Aug 1945

I thought I read that they had used smaller ones (specifically, P-40 drop tanks). Do you have more data on that?