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

[Shortround6]

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.

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

In one sense you are correct but I would suggest that the Griffon would parallel Merlin, using the same boost limits as the Merlin at about the same times.

Also note that any estimates of 1939/early 1940 perfromance would be with a Pre-Hooker supercharger and not the Merlin XX/45 design.

 

[ThomasP]

A developed 'R' engine (ie Griffon I) was a possibility, but they stopped development sometime in the mid- to late-1930s in order to work on a clean-sheet design which became the Griffon II.

The Rolls-Royce 'R' racing engine.

In the 1929 Snyder Cup race the 'R' ran at 1800 BHP for 40 min. They were using a special racing fuel blend that (If my info is correct) had an approximate PN of 95/125.

In 1934 Rolls-Royce was running 100 hr at 1500 BHP endurance tests on a modified 'R' engine as part of the development for the Griffon I. The Griffon I development was discontinued after about 1937 or 38(?) and work started on the clean-sheet Griffon II.

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

 

[z42]

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.

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.

To an extent the prime virtue of the Hurricane vs. the Spitfire was that they could build them faster and cheaper. But for a carrier aircraft in particular, it makes even less sense to focus on cheapness than for a land based aircraft as the carrier is a very expensive asset and space is at a premium. So you want your planes to be the best you can get. Or most capability per used space in the hangar, or however you want to measure it. Also significantly easier to sink a carrier than an airfield, thus putting even more importance in being able to fend of attacks.

Of course, if strapping a hook on a Hurricane makes for a quick stopgap interceptor while working on a proper Seafire, by all means, but priority should absolutely be a Spitfire based interceptor (if one has to choose between Sea Hurricane and Spitfire).

 

[Admiral Beez]

Was it not 1943?

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.

 

[z42]

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.

Wasn't Eagle already in development by then?

 

[Wild_Bill_Kelso]

I still say a fighter long endurance (with decent speed) is still better than an interceptor for carrier ops.

 

[Admiral Beez]

Wasn't Eagle already in development by then?

IDK. Wikipedia has it first running in 1944. No info on when it started. Rolls-Royce Eagle (1944) - Wikipedia

But RR should have focused on maximizing the Griffin and then prioritized on the Derwent and follow-on jet engines. The Crecy and Eagle are clearly distractions.

 

[tomo pauk]

I still say a fighter long endurance (with decent speed) is still better than an interceptor for carrier ops.

Drop tanks make wonders.

 

[z42]

In one sense you are correct but I would suggest that the Griffon would parallel Merlin, using the same boost limits as the Merlin at about the same times.

Also note that any estimates of 1939/early 1940 perfromance would be with a Pre-Hooker supercharger and not the Merlin XX/45 design.

Fully agreed. In my fantasy scenario, Merlin would still be priority #1, as it historically was, for good reasons. But IMHO #2 should have been Griffon, then as a follow-up to Griffon as priority #3 look into something slightly more exotic (much as the V-12 is a really nice layout, for something substantially bigger than Griffon the per-cylinder volume starts to get awfully big in a V-12 configuration). But keep that as boring and safe as possible too. A poppet valve H-24 would reduce risks with bearings/crankshafts like X-layout Vulture suffered from, and also not go down the sleeve valve rabbit hole like Crecy or Eagle. Then all the two-stroke, sleeve valve, X layout, air cooled inlines, etc. stuff can be done as science projects with relatively low funding.

 

[tomo pauk]

But IMHO #2 should have been Griffon, then as a follow-up to Griffon as priority #3 look into something slightly more exotic (much as the V-12 is a really nice layout, for something substantially bigger than Griffon the per-cylinder volume starts to get awfully big in a V-12 configuration). But keep that as boring and safe as possible too.

How bad would've been the 'British DB 603', displacement-wise?

 

[Shortround6]

How bad would've been the 'British DB 603', displacement-wise?

Kind of depends on what the British will accept for fpm of piston speed and what they want for engine life.

DB603 with 2550rpm?
DB 603 used pistons 10mm bigger than the Griffon and 8mm bigger than DB 605.
British have better alloys?

 

[tomo pauk]

Kind of depends on what the British will accept for fpm of piston speed and what they want for engine life.

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

DB603 with 2550rpm?
DB 603 used pistons 10mm bigger than the Griffon and 8mm bigger than DB 605.
British have better alloys?

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

 

[Wild_Bill_Kelso]

Drop tanks make wonders.

I don't think external tanks are enough for a plane like a Spitfire ... otherwise they would have been escorting strikes to Berlin. Or at least Hamburg. Same applies to Bf 109 or MC 202. Or most of the Soviet fighters.

 

[Shortround6]

I still say a fighter long endurance (with decent speed) is still better than an interceptor for carrier ops.

They tested an F4F-3 with underwing "slipper" tanks, not adopted.

They put a pair 58 US gal tanks under F4F-4s or FM-1s but apparently not until 1943 or later?

Of course a pair of 58 gal tanks under an F4F may kill the notion of decent speed.

 

[Wild_Bill_Kelso]

They tested an F4F-3 with underwing "slipper" tanks, not adopted.

They put a pair 58 US gal tanks under F4F-4s or FM-1s but apparently not until 1943 or later?

Of course a pair of 58 gal tanks under an F4F may kill the notion of decent speed.
View attachment 745248

yeah these show up quite a bit in the later war, on FM-2 as well I think. I think they are good - if you need to scramble to altitude they can be dropped. If they are flying around on a long CAP mission and detect enemy strike incoming they can immediately drop the external tanks (and probably still have pretty full internal tanks). They can also use the fuel on the way to the target on an escort mission.

The key thing is that the Wildcat still has decent range without the external tanks. So if they do have to drop them on a long flight, they can still make it back to base.


This is a wonderful photo by the way.

 

[tomo pauk]

I don't think external tanks are enough for a plane like a Spitfire ... otherwise they would have been escorting strikes to Berlin. Or at least Hamburg. Same applies to Bf 109 or MC 202. Or most of the Soviet fighters.

How much fuel was carried by a Fulmar, internal + external?

 

[Shortround6]

How much fuel was carried by a Fulmar, internal + external?

I believe 155 imp gal internal and 60 imp gal belly tank?

 

[Wild_Bill_Kelso]

How much fuel was carried by a Fulmar, internal + external?

155 (I think Imperial) gallons internal.

They had some kind of 60 gal tank for them, which was carried on the centerline. Don't know if they ever developed / plumbed for (external) wing tanks.

 

[tomo pauk]

155 (I think Imperial) gallons internal.

They had some kind of 60 gal tank for them, which was carried on the centerline. Don't know if they ever developed / plumbed for (external) wing tanks.

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.

 

[don4331]

A developed 'R' engine (ie Griffon I) was a possibility, but they stopped development sometime in the mid- to late-1930s in order to work on a clean-sheet design which became the Griffon II.

The Rolls-Royce 'R' racing engine.
View attachment 745241

In the 1929 Snyder Cup race the 'R' ran at 1800 BHP for 40 min. They were using a special racing fuel blend that (If my info is correct) had an approximate PN of 95/125.

In 1934 Rolls-Royce was running 100 hr at 1500 BHP endurance tests on a modified 'R' engine as part of the development for the Griffon I. The Griffon I development was discontinued after about 1937 or 38(?) and work started on the clean-sheet Griffon II.

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

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.

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.