Alternatives to the Fairey Firefly?

[tomo pauk]

What might be the alternatives? Requirement is still the crew of two, 4 cannons, full carrier-vessel capability (low-speed handling, visibility, folding wings, tailhook, then-current electronics, overall protection from the salt water/air environment), long range & endurance. In service by late 1943/early 1944, Made in UK.
"Clean sheet of papers" A/C encouraged, but not mandatory

 

[tomo pauk]

Staying single-engine, perhaps go with 'big 2-seat Spitfire'/'big 2-seat P-51'/D4Y/C6N/'two-seat Tempest' appearance? Engine of choice the Merlin 66 (as on the Spit XI LF), so there is a slight reduction of weight and fuel consumption vs. Griffon (= less fuel needs to be carried = again lower weight). Wing - generally copy the shape and airfoil from Spitfire, but phisically thicker and bigger, talk 300 sq ft (vs. 330 on the historical Firefly), with Youngman flaps. 150 imp gals of internal fuel + drop tanks should keep the aircraft aloft for a long time.
For post-war service, go with Merlin 130s, Hispano V and updated electronics.

 

[special ed]

The Henley with a Griffon and a tail hook.

 

[don4331]

Isn't the Hornet the historical alternative. Check for all of: crew of two, 4 cannons, full carrier-vessel capability (low-speed handling, visibility, folding wings, tailhook, then-current electronics, overall protection from the salt water/air environment), long range & endurance. Just have DH build it instead of Mosquito.

Or add a second seat to the Firebrand. Blackburn's "strike fighter" checks all the boxes except 2 seater.

 

[PFVA63]

Hi,
I would probably look at other designs from around that time. I wouldn't necessarily say to take "plane A" and just make a few changes, but instead maybe you could take an existing design or proposal and leverage its technology for a new design, kind of how as I understand it Fairey leveraged work from an existing proposal (I think the P.4/34) as a starting point for the Fulmar.

As such, maybe the Hawker Henley or the Boulton Paul Defiant (and/or some of the other concepts they were working on around then) might be a good starting point.

In particular, the thought of a plane similar to the Defiant, but with a space for a radio man and equipment instead of a heavy turret seems like it might be an interesting place to start.

Pat

 

[EwenS]

Isn't the Hornet the historical alternative. Check for all of: crew of two, 4 cannons, full carrier-vessel capability (low-speed handling, visibility, folding wings, tailhook, then-current electronics, overall protection from the salt water/air environment), long range & endurance. Just have DH build it instead of Mosquito.

Or add a second seat to the Firebrand. Blackburn's "strike fighter" checks all the boxes except 2 seater.

First question. Which carriers do you want it to operate from?

Folded width 27ft 6in. So only operable from Indomitable, Implacable and Indefatigable with their larger (33ft wide) forward lifts) and light fleets. Other Illustrious class and aft lifts on the three named were only 22ft wide. It also has a significantly larger deck footprint when compared to a Firefly. Probably also weight issues for catapulting & arresting in WW2 period on at least some of those ships.

Also first designed as a long range single seater to a July 1944 spec N.5/44. Prototype first flew April 1945 & deck landed in Aug. First production aircraft flew March 1946. Night fighter followed to an urgent 1945 requirement to spec N.21/45. Prototype was a single seater converted and flew as NF in July 1946. Also depended in large part for its low frontal area 2,000hp Merlin 130 series engines specially developed for it.

Problem with any alternative is the engine. IIRC two main candidates in 1939/40 were the single stage Griffon or the Napier Sabre. Blackburn's original Firebrand proposal used a Hercules but that was quickly superseded by the Napier Sabre. Come 1941 the RAF had priority for that engine for the Typhoon. That meant a change to the Centaurus.

Griffon II seems like the only possibility in 1939/40 when you are selecting a design as an alternative to Firefly.

 

[Shortround6]

Griffon II seems like the only possibility in 1939/40 when you are selecting a design as an alternative to Firefly.

It is the only one that is viable in hindsight.

Tony Butler's book

has got a crap load of designs for naval fighters from that 1938-1940 period.
Including a bunch of Blackburn Roc replacements.

 

[don4331]

The Short Sturgeon was only 20' wide with wings folded, so a twin Merlin airplane could be built narrow enough - might be a little tight on 22' wide lift, but would be possible - getting a reverse rotation or contra-rotating engine in 39/40 might be equally difficult.

I forgot the Henley with a Vulture as possibility.

I wonder if a couple other plane types had used the Peregrine or Vulture, if RR would have continued them...

 

[ThomasP]

As we know, due to the rationalization program of the early-war Rolls-Royce ended up stopping work on the Vulture engine in late(?) 1941. But from what I have read, as of late-1941 the Vulture engine design (as developed in the Vulture V) was a viable engine. In late-1942 the Vulture was even tested with contra-rotating propellers. The Vulture V passed 100 hr type testing in early-1942(?) and ratings were 1995 BHP for TO, with 2035/1840 BHP at 5,000/20,000 ft in Mil.

see "Rolls-Royce Vulture X-24 Aircraft Engine"

In 1939, Avro and Cunliffe-Owen had been contracted to produce the Hawker Tornado (Vulture engine), to the tune of ~2000 airframes.

Maybe hand off continued development of the Vulture to Armstrong-Siddeley? Armstrong-Siddeley was bought by Hawker in 1935 so coordination was already established by WWII. With an additional 1-2 years of development who knows what might have resulted?

Avro already had experience with the Vulture engine on their Manchester bomber. If we assume Avro was able to contribute to our Firefly alternative, that would mean a few less Lancasters (maybe), but allow significant production numbers.

Cunliffe-Owen was a main contractor for the Seafire Mk III and later the Mk XV. IIRC they were also busy with navalization & modifications of other FAA airframes, so they obviously understood the problems and had the ability to build and modify airframes for carrier use. If we assume that our Firefly-alternate was only needed in historical small numbers then it could be built by Cunliff-Owen (maybe).

Or possibly, a coordinated joint production effort by Avro and Cunliffe-Owen would be the answer.

The Vulture and the resources that had been intended for the Tornado would seem to fit the bill in the time frame we are considering.

The only question in my mind is who would be responsible for design and development of the airframe. Maybe Hawker?

 

[EwenS]

In the 1939/40 timeframe I think any twin engined design is out of the window for the FAA. With the RN just having regained complete control of the FAA they would not be so adventurous. Until then only the French had succeeded in operating a twin from a carrier (the Potez 565 transport for trials in Jan 1936) although Grumman was developing the single seat XF5F Skyrocket which first flew on 1 April 1940. Britain didn't deck land the Mosquito until March 1944 and the Hornet until Aug 1945, and the USN the B-25 until Nov 1944. That is even before considering the practical problems I touched on before and of which there is more information below.

In terms of engines, "Fairey Firefly" by W Harrison indicates 4 possibilities were considered by Fairey initially. Bristol Taurus, Fairey Queen (later renamed Monarch complete with contra-props) and Rolls Royce Griffon & Boreas (aka Exe) of which the Griffon offered the best possibilities, being the most powerful as things then stood. The Napier Sabre was also added in slightly later before their proposal was submitted.

Rolls-Royce Exe (Boreas) and Pennine Aircraft Engines

From the late 1930s to the mid-1940s, Rolls-Royce developed two air-cooled X-24 aircraft engines: the 1,200 hp (895 kW) Exe and the 2,800 hp (2,088 kW) Pennine. Neither engine entered production.

oldmachinepress.com

Fairey P.24 Monarch Aircraft Engine

Designed by Richard Forsyth, the P.24 Monarch was Fairey Aviation’s final attempt to enter the aircraft piston engine business. The 24-cylinder Monarch was essentially two engines in a common crank…

oldmachinepress.com

The companies invited to tender were:-
Blackburn Aircraft Co Ltd
Boulton Paul Ltd
Fairey Aviation Co Ltd
Gloster Aircraft Co Ltd
Hawker Aircraft Co Ltd
Vickers Armstrong Ltd
Westland Aircraft Ltd

There were a number of problems for companies trying to meet the requirements. Firstly the RN wasn't entirely sure what it wanted. Initially they wanted a two seat fighter and a two seat turret fighter built on basically the same airframe to specs N.8/39 and N.9/39. Then they decided to drop the latter. Then a requirement for single seat fighter emerged during the design process maybe / maybe not based on the same airframe as the two seater, something the companies only learned about through the grapevine initially. And the performance target was raised from 275 knots to 330 knots at 15,000ft although the latter was seen as challenging.

N.8/39, for a single engined two seater, set a max weight limit of 10,500lb (preferably 9,000lb). This is more or less fixed by the then carrier accelerator / catapult limits of the BH.I & BH.III accelerators being fitted to British carriers. Height 13'6" set by the 14' hangar height of the Indomitable (upper only) and Implacable class carriers then building. Folded width 13'6". This would have allowed them to be stowed four abreast in the 62ft wide Illustrious/Implacable class carrier hangars instead of the more normal three abreast so effectively increasing carrier capacity. That is the folded width of a Seafire III or XV/XVII and the Firefly. Length 40' (remembering that the carrier lifts were about 45' long). Span unfolded 50'. Take off distance 300ft in a 20knot wind. Stall speed not to exceed 58 knots fully loaded. 6 hours endurance at 120+ knots at 15,000 ft + 15 mins at sea level. 8x.303MG or 4x20mm Cannon.

There was also a very compressed timetable. The specs were only approved by the RN in June 1939, tenders invited on 10 Aug, to be submitted by 19 Sept. Westland asked for more time and was refused, but the deadline was later moved to 19 Oct. The Tender Design Conference, twice postponed, took place on 5 Jan 1940 at which it was decided the Fairey design for what became the Firefly was deemed most suitable. That led to orders in May/June 1940. Also a decision was made at that Conference to pursue a single seat Hercules powered Blackburn proposal. That became the Sabre powered Firebrand to spec N.11/40 issued in Aug 1940.

At the Tender Design Conference some suggestions to speed up the process were suggested. A Hawker Tornado with new wings, fuselage and tail unit. Spitfire with Griffon engine.

So from the above suggestions by posters the Hawker Henley is too tall (14ft 7.5in) without modification (and adding a longer Griffon engine probably makes things worse) as was the Tornado (hence some of the need for a new fuselage) not to mention the Tempest and although a navalised P-51 might work, it is too late timewise not even being designed by the time the Firefly was selected. Defiant meets the height criteria. Hornet is too wide (as is the Sturgeon) besides both being twin engined.

Unfortunately I don't have BSP3 in the library to see the other proposals for these specs.

One feature that is regularly criticised in RN planning is the low specified stall speeds. Some relaxation of these at an earlier date would have helped the designers of the Barracuda, Firefly and Firebrand. Not so much need for all the fancy flappery on the wings to reduce landing speeds and take off distances (the latter also being something affected by the long round downs on British carrier flight decks of the period that have the effect of reducing available deck space).

So there are a few physical limitations that people need to take into account when thinking about their designs.

 

[SaparotRob]

I liked your post, EwenS. Fancy flappery got it to "winner".

 

[GreenKnight121]

In the 1939/40 timeframe I think any twin engined design is out of the window for the FAA. With the RN just having regained complete control of the FAA they would not be so adventurous. Until then only the French had succeeded in operating a twin from a carrier (the Potez 565 transport for trials in Jan 1936) although Grumman was developing the single seat XF5F Skyrocket which first flew on 1 April 1940. Britain didn't deck land the Mosquito until March 1944 and the Hornet until Aug 1945, and the USN the B-25 until Nov 1944. That is even before considering the practical problems I touched on before and of which there is more information below.

The USN had nicely successful tests of a tricycle landing gear & arresting hook equipped Lockheed Electra Junior from USS Lexington in August 1939.

 

[EwenS]

I liked your post, EwenS. Fancy flappery got it to "winner".

The chosen alternative design to the Barracuda was the Supermarine Type 322 "Dumbo". It was much delayed and never went beyond a couple of prototypes. It used a variable incidence wing connected to the operation of the flaps to achieve the required stall speed.

Supermarine Type 322 - Wikipedia

en.m.wikipedia.org

Such were the lengths that designers were having to go to to reduce stall speeds in the late 1930s to meet specs for aircraft for the FAA.

 

[yulzari]

Thinking about speed of introduction rather than outright performance, how about doing a Spitfire job by slotting a Griffon onto the Fulmar as a quick and dirty upgrade?

 

[tomo pauk]

Thinking about speed of introduction rather than outright performance, how about doing a Spitfire job by slotting a Griffon onto the Fulmar as a quick and dirty upgrade?

Agreed.
OTOH - even going with a 'proper' Merlin, like something from the 20 series is a boon. vs. the historical Fulmar.

 

[EwenS]

Thinking about speed of introduction rather than outright performance, how about doing a Spitfire job by slotting a Griffon onto the Fulmar as a quick and dirty upgrade?

While the RR Griffon owed its ancestry to the Schnieder trophy R engines, the Griffon that served from WW2 was an entirely different engine. Development of the Griffon II engine wasn't begun until 1939. It ran for the first time in Nov 1939. IIRC it first flew in 1941. Spitfire IV prototype with the Griffon III flew Nov 1941, Firefly I prototype with Griffon II flew Dec 1941. Production Griffon engines became available in 1942. The first production Spitfires with it were Mk.XII from Oct 1942 and production standard Fireflies had started to come off the production line around May 1943.

The first production Fulmar rolled of the production line in Jan 1940 and the first unit formed with them in July. Given that, at the beginning of 1940, it is the only fighter the FAA has a prospect of getting in the near future, and how badly it needs a modern fighter, why would you want to delay and disrupt its production?

Fulmar with Griffon would only have appeared in the same timescale as Firefly. Effectively a Fulmar with a Griffon is Firefly.

Edit:- the last Fulmars came off the production line in Feb 1943.

 

[EwenS]

Agreed.
OTOH - even going with a 'proper' Merlin, like something from the 20 series is a boon. vs. the historical Fulmar.

Given that most FAA action was against enemy aircraft at lower altitudes, I'm not sure just how much of an improvement in real world performance would have been achieved by fitting a Merlin 20 series over the Merlin VIII/30 in the Fulmar I/II.

 

[tomo pauk]

Given that most FAA action was against enemy aircraft at lower altitudes, I'm not sure just how much of an improvement in real world performance would have been achieved by fitting a Merlin 20 series over the Merlin VIII/30 in the Fulmar I/II.

Firefly received the Griffon, that was pretty good between 15000-20000 ft.
Even for the down-low purposes, the Merlin 20s were useful, making 100-250 HP more than the Mk.30 Merlin.

 

[Shortround6]

Firefly received the Griffon, that was pretty good between 15000-20000 ft.
Even for the down-low purposes, the Merlin 20s were useful, making 100-250 HP more than the Mk.30 Merlin.

A lot depends on timing.
According to Wiki (correction welcome)

"During January 1941, production of the improved Fulmar Mk II commenced; the first Mk II aircraft was delivered to an operational squadron in March 1941.[14]​ This model of the aircraft was furnished with the more powerful Merlin XXX engine"

The Merlin XXX was rated at 1360hp at 6000ft using 12lbs of boost. It used the same 8.588 supercharger gear as a MK III Merlin did but used a 9.75in impeller instead of the 9.50 in impeller of the Merlin 45M.

It took a while for the Merlin XX engines to be allowed to exceed 12lbs of boost and in fact the early models (until the Merlin 24) were never rated at over 14lbs of boost in low gear although 16lbs boost allowed in high gear. At 14lbs of boost the Merlin XX was rated at 1485hp at 6000ft so yes, there were about 125hp extra once the higher boost rating 14lbs was allowed. At 12lbs the difference may have been a bit less, the Merlin XXX used the same supercharger (Non-Hooker inlet) as the Merlin III.

Since it was not until near the end of 1942 that the Merlin XX, 21, 22, 23 were allowed to use 14lbs pounds of boost?

The Merlin 24 was allowed to use 18lbs of boost and that is where the large increase in power came from. But this required a lot of modifications from the Merlin 23 and lower numbers.

The Merlin 32 offered 1640hp at 2,000ft with 18lbs of boost and since it used the same supercharger gear and impeller in the Hooker designed intake, and two piece engine blocks and modified supercharger drive as the Merlin 24 got it doesn't seem that it should have been any later in timing if they had wanted it. Or offered much difference in power from the cropped impeller Melrin 45s. A little bit higher gear from a slighlty smaller impeller. 1585hp at 2750ft instead of 1640 hp at 2,000ft?

 

[tomo pauk]

The Merlin 32 offered 1640hp at 2,000ft with 18lbs of boost and since it used the same supercharger gear and impeller in the Hooker designed intake, and two piece engine blocks and modified supercharger drive as the Merlin 24 got it doesn't seem that it should have been any later in timing if they had wanted it. Or offered much difference in power from the cropped impeller Melrin 45s. A little bit higher gear from a slighlty smaller impeller. 1585hp at 2750ft instead of 1640 hp at 2,000ft?

Merlin 32 was still an one-altitude-band engine, unlike the Merlin 20s or the Griffon.
Having the over-boosted Merlin 20 series for the Fulmar in whole of 1943 is a boon wrt. the crucial operations in the MTO that unfolded.