Bistol Type 153 wins the F.37/35, no W. Whirlwind

[Admiral Beez]

There are several problems with the type 153 especially for a carrier fighter.

I'm more interested in the Type 148 as genesis for a fleet fighter, but single seat. It's the same span and size as the Hurricane.

Again, I'm not suggesting bolting a 875 kg, 55in dia Hercules onto the nose in place of a 590 kg, 46in dia Taurus. But using some of its design may get Bristol ahead of the Fulmar.

40ft wide straight chord wing need to go - you won't be rolling this in a hurry otherwise. But look at the single seat option below.

Swap in a scaled up version of the Type 146's 39 ft wide wing.

Or make me a single seat Fulmar that's lighter and we can toss the lot.

 

[Thumpalumpacus]

An earlier Beaufighter [...]?

This could be a damned good thing.

 

[Admiral Beez]

This could be a damned good thing.

Indeed. Imagine swapping out the Blenheims at Malaya and Ceylon with Beaufighters.

 

[Thumpalumpacus]

Indeed. Imagine swapping out the Blenheims at Malaya and Ceylon with Beaufighters.

Right. Or imagine Bismarck's maiden voyage, or Operation Cerberus, with Beaufighters or Torbeaus working to track and kill the ships instead of six Swordfish and some BC heavies. Seems like a much better strike-package than either alternative.

 

[Admiral Beez]

Right. Or imagine Bismarck's maiden voyage, or Operation Cerberus, with Beaufighters or Torbeaus working to track and kill the ships instead of six Swordfish and some BC heavies. Seems like a much better strike-package than either alternative.

It is amazing that an island nation with a first rate aeronautics industry like Britain got to Sept. 1939 without a high performance maritime strike aircraft akin to the Beaufighter (or Mosquito).

Italy had their 290 mph, twin torpedo SM.79 Sparviero from 1936. Meanwhile, three years earlier the RAF introduced their new torpedo bomber, the 143 mph Vickers Vildebeest, which served in frontline service in some measure until early 1942 before they were replaced by the Beaufort and Hampden, both single torpedo armed.

 

[Shortround6]

I'm more interested in the Type 148 as genesis for a fleet fighter, but single seat. It's the same span and size as the Hurricane.

I am not sure where the fascination of trying to redesign aircraft for missions they were never intended to fill comes from.

OK, lets start with the Type 148 BUT

let's throw out the wing. BUT

lets throw out the pilots cockpit. BUT

Let's throw out the 2nd seat, Rear gunner was supposed to lay prone in the rear cockpit to operate a bomb sight. Large fuel tank under the Pilots cockpit?

So we have throw out the wing and much of the fuselage from the firewall back to a bit in front of the tail BUT

The 148 was never designed to perform fighter maneuvers.

Fighters and dive bombers were designed to handle higher G loads than other types of aircraft, BTW, transport aircraft, in general, had the lowest G ratings/load factors.
Think about why.

And finally since you aren't going to use the Hercules or the Taurus engines you are left with Merlin which means now you throw out everything forward of the firewall.

What's left? the tail and the spated tail wheel?

Again, I'm not suggesting bolting a 875 kg, 55in dia Hercules onto the nose in place of a 590 kg, 46in dia Taurus. But using some of its design may get Bristol ahead of the Fulmar.

Using the Taurus, no matter how good in may have looked om the brochures in 1938-39 would have doomed any fighter trying to use in in 1940-41.

 

[EwenS]

It is amazing that an island nation with a first rate aeronautics industry like Britain got to Sept. 1939 without a high performance maritime strike aircraft akin to the Beaufighter (or Mosquito).

Italy had their 290 mph, twin torpedo SM.79 Sparviero from 1936. Meanwhile, three years earlier the RAF introduced their new torpedo bomber, the 143 mph Vickers Vildebeest, which served in frontline service in some measure until early 1942 before they were replaced by the Beaufort and Hampden, both single torpedo armed.

Please don't hold out the Regia Aeronautica as an example of how the RAF should have built its torpedo bomber force in the 1930s!

Firstly the RA and the RM couldn't agree on who should have responsibility for that function. Secondly, the RA only carried out torpedo dropping experiments between the wars. It didn't have an operational torpedo bomber function of any kind until 1940. While the SM.79 might have been around since 1934, and entered service in 1936, the Italians didn't order their first production batch of 30 aerial torpedoes until late 1939 / early 1940 and a follow up batch of 50 in July/Aug 1940. The first SM.79 torpedo bomber unit wasn't formed until 25 July 1940. In the first couple of weeks of its existence it received 7 SM.79 modified for torpedo dropping. That was just in time to move to Libya to carry out its first unsuccessful operation on 15 Aug. Their first success came on 17 Sept 1940, HMS Kent being damaged. The force then built from there.

You quote the max speed of the SM.79 as 290mph. But that is as a bomber without a bloody great torpedo hanging off its belly and at 12,430 feet, not at sea level. While in theory it could carry two torpedoes, it had been found in testing before the first mission that carrying two seriously impaired the aircraft performance (I've seen 200mph max suggested in that configuration). After that 2 torpedoes were only carried while the aircraft were on transport duties between bases.

The first Beaufort squadron (max speed 275 mph at 6,500 feet, 252mph at sea level) became operational in April 1940. So seemingly a very similar level of performance. And it achieved its first success on 18 Sept 1940, the day after the Italians.

The important thing about torpedo dropping is not the max speed of the dropping aircraft but the max speed and height at which the torpedo can be dropped without being damaged on hitting the water or hitting it at the wrong angle such that it deviated from its intended course. Torpedo dropping was an art that required practice. Max dropping speeds for the British Mk.XII torpedo in 1940 were 180 mph from 70 feet. Later, as the Monoplane Air Tail began to be fitted, to control the descent of the torpedo, dropping speeds increased to 220mph from 150 feet with Barracuda and Beaufighter. But that is still substantially less than the max speed of a Beaufighter X at sea level (305mph).

The Italian Whitehead torpedo could be dropped over a height range of 40-120m (130-390ft) but was limited to a dropping speed of 190mph.

Only in the Far East did the Vildebeest remain in service beyond April 1940. And that was because the planned replacement, Beauforts from the Australian production line, were delayed due to the need to set up an Australian aircraft industry from scratch and a lack of assistance from Britain due to the war being on. The first Australian machine didn't leave the production line until 22 Aug 1941.

The Beaufort was intended (pre war) as the RAF's principal torpedo bomber and entered service in late 1939 with the first squadron operational in April 1940 as noted above and the second receiving its aircraft. It was shortage of these aircraft that saw 2 squadrons of Wellingtons in the Med transferred to the anti shipping role from Dec 1941 / early 1942. Those aircraft could carry 2 Mk.XII torpedoes. At home, the shortage was met by the transfer of 2 Hampden squadrons from Bomber Command in April 1942. But it took several months before they were trained in torpedo dropping.

 

[don4331]

I wouldn't say was an art, but it is one of the most difficult deflection shots:

As there were practically no mechanical aids, you are relying on the Mk. 1 eyeball and brain, to identify the ship correctly - e.g. Bismarck and Admiral Hipper classes are very similar in shape yet the BB is much larger, which is confusing when estimating range; the speed of the ship, the angle between the ship and you. Then you need to fly your plane to the correct position ahead and abeam, making sure you aren't turning, skidding or rolling your bomber (which would upset the torpedoes gyros). All while under a barrage of AAA trying to kill you. And even if you get everything right, the target might perform evasive maneuvers or your torpedo has issue(s) and you miss.

So, yes, constant training was required and only the most talented could get it right.

I'm trying to find where I read the IJN aerial torpedo successful runners statistics: If I remember correctly, they went from good chance of successful runner at the 20m altitude/150kn speed to atrocious at the maximums. High performance aircraft have difficult time slowing down to those speeds, and slowing down early to ensure they are at those speeds when required puts your fast airplane at same risk to CAP/AAA as the low performance aircraft - so why risk a more expensive plane?

Torpedo bombing is right up there with attacking a rhino with a spear.

 

[don4331]

Using the Taurus, no matter how good in may have looked om the brochures in 1938-39 would have doomed any fighter trying to use in in 1940-41.

Gloster Reaper, aka Gloster F.9/37, with 360 mph from twin Taurus on the prototype should still be holding up OK in 1940-41 as a heavy fighter. I'd put it right in same performance range as the Bf.110C's. I wouldn't want to be in He.111 on receiving end of the 4 - RCMG and 2 Hispanos.

I do wonder what a Whirlwind with Taurus would have looked like - Fedden certainly wanted Petter to prototype one.

 

[Shortround6]

The prototype Taurus engines used the Prototype Gloster Reaper disappeared after a short while and never came back. The prototype was re-engined with a different version of the engine and the speed dropped to 330mph.
Plane had been damaged in a crash and I don't know if any other changes were made.
The service Beauforts were given engines that peaked at 3-4000ft as were the Albacores.
This is perfectly fine for a torpedo bomber engine but doesn't leave much scope for a fighter engine.
Engine in the Fulmar was good for 6,000ft.
They spent a lot of 1940 (and early 41?) Trying to get the engines to cool properly at low altitude which doesn't sound hopeful for a 12,000ft and up engine trying to run in thinner air with a higher intake temperature (higher supercharger gear).
The Taurus was certainly was proposed for a lot of schemes in the late 30s, perhaps because they put more importance on size/frontal area than they did on better airflow/baffling ?

 

[Admiral Beez]

Pretty conventional Type 153 was to be powered by a Bristol Hercules, armed with 4 cannons (per spec), and was among the 1st designes supposed to have the bubble canopy. Let's say Bristol's design wins instead of Westland's.
Will the RAF be better off, or not? Possible repercussions on future British, German and/or US fighter designs? The FAA version?

Going back to the original post. The Whrilwind was a dead-end, so replacing it with something that uses what becomes a mainstream engine can only be a plus, even it the Type 153 doesn't enter widespread service until 1941. It will presumably lead to Bristol offering a single engined fighter concept for its Centaurus in 1944.

 

[don4331]

Gloster F9.37
Losing >15% of power, hurts top speed.

At least if you are building an aircraft for Taurus, it leaves door open for P&W R-1830s - while couple inches larger in diameter, it offers more power at higher altitude.

Whirlwind
Why is Westland's fighter a dead end? I'll acknowledge it was expensive, but it remained in service for 2 full years after the last one was produced.
Build Peregrine's rated for 12 psi for use with 100 octane* and Whirlwind is probably deadly against FW.190s in '41 and beyond (it certainly held its own versus Bf.109Es through summer of '41 down low);
As the slats are wired shut, use the leading edge as fuel tank, adding the fore & aft cockpit fuselage tanks which doubles range, plumb it for a center-line fuel tank and range increases further still.
Replace the 60 rd drums with belt feed and more than double ammunition available.
All changes above were suggested by WEW Petter for Whirlwind II.

Actually, you could further strengthen the Peregrines to 16 psi (100 octane limit) add 2nd speed to Peregrine and fix the propeller issue and it will hold its own at altitude through '43 at least;

The problem is more - Westland should have built & flown the prototype with Kestrels (and a hundred kg of lead to simulate the heavier Peregrine), so RR wouldn't be using decision on counter rotating engine (Peregrine II) as reason for delaying production. And they should have reduced Lysander production and concentrated on Whirlwinds, letting the semi complete fighters sit outside plant waiting engines. That would pull squadron deployment by 3+ months, allowing Whirlwind to be part of the BoB legacy and much harder to kill off.
Doesn't help that Petter, like Fairey was hard to deal with.

 

[wuzak]

Going back to the original post. The Whrilwind was a dead-end, so replacing it with something that uses what becomes a mainstream engine can only be a plus, even it the Type 153 doesn't enter widespread service until 1941. It will presumably lead to Bristol offering a single engined fighter concept for its Centaurus in 1944.

Hard to know in 1937 that the war would start in 1939, that Peregrine development would be delayed/cancelled not long after, nor what would be a mainstream engine for the RAF, other than the Merlin.

Replace it with an aircraft designed around 2 Merlins instead of 2 Peregrines. Could be a redesigned Whirlwind, could be the Supermarine Type 327*, or something else.

One Tornado prototype was converted to use the Centaurus in 1942, and first flew in December 1942. Why Bristol would wait until 1944 to offer a concept for a Centaurus fighter?

*The Supermarine Type 327 was designed as a backup to the Whirlwind as a cannon armed fighter, but it lost out to the Bristol Beaufighter. The Type 327 was a development of the Type 324, which competed against the Typhoon/Tornado for the F.18/37 specification.

 

[Shortround6]

Hawker Tornado first flown October 23rt 1941.
More work needed to be done on the cowl and the Centaurus engine. Note the single exhaust pipe on the early version.

Same aircraft in Dec 1942 after modifications.
While a prototype Vickers Warwick flew with Centaurus engines in 1940 there were no production versions until 1943.
Centaurus engines started at around 2,600-2,700bs each or over 800lbs more than a Hercules engine. Designing a plane to hold a 2500hp engine instead of a 1600-1700hp engine also requires a few changes.

The Supermarine 324-327 looks a very careful examination.

That does not look like a very thin wing and these designs were being worked on without a lot of knowledge of high speed flight, much like the P-38.
Possibility of compressibility problems?
Also while the provision of Fowler flaps was forward thinking the implementation may have been a bit off. For flaps (or leading edge slats) to do the most work they needed to be applied over the most wing they can be used on.

One source claims the Supermarine flaps were only between the engines and the fuselage?
Could be wrong.
Another source claims fuel capacity was 220imp gallons?

 

[tomo pauk]

The Supermarine 324-327 looks a very careful examination.

That does not look like a very thin wing and these designs were being worked on without a lot of knowledge of high speed flight, much like the P-38.
Possibility of compressibility problems?

'Warrants' instead of 'looks'?
I've done some eyeballing years ago using the measuring tool at PDF viewer, the root wing profile is at about 20%. Makes P-38 look wonderful in that regard with 16%.

 

[Geoffrey Sinclair]

Some engine production figures and costs.

Ministry of aircraft production figures, 71 Hercules and 1,580 Merlin June to December 1939, and 636 Hercules and 6,844 Merlin in 1940. In presenting the figures the Ministry chose to use monthly average for the quarter, which means total the production for the quarter, divide by 3 and round. So Hercules quarterly figures for 1940 are 22, 42, 84, 64, total 212, times 3 = 636. Merlin figures for 1940 are 305, 607, 686, 683, total 2,281, times 3 = 6,843.

Finding prices paid for engines is difficult. As of 31 May 1941 Avia 15/950 has aircraft purchase costs including an allowance for spare engines, this is not the cost of an engine and in fact may reflect different expected lifetimes as well as purchase price, essentially it is the cost of spare engines divided by the number of aircraft in the order. Assuming spare engines were provisioned in the same proportion, the costs in pounds Lancaster spare engines 1,750 per aircraft, Stirling 2,500, or about 43% more.

Spitfire spare engines were 450 pounds per aircraft, same as the Mosquito. Griffon Spitfire 600 pounds per aircraft. Wellingtons 1,300 pounds per aircraft. Oxfords 400 pounds per aircraft.

The Australians costed a Hercules in 1943 as 4,400 Australian pounds, about 3,500 pounds Sterling. Web sources talk about 2,000 pounds Sterling for a Merlin.

 

[Admiral Beez]

Hard to know in 1937 that the war would start in 1939,

I'm referring to serendipity rather than forethought.

Why Bristol would wait until 1944 to offer a concept for a Centaurus fighter?

My bad, I meant entry into service by 1944, and in the worst case. Earlier is likely.

 

[EwenS]

I'm referring to serendipity rather than forethought.

My bad, I meant entry into service by 1944, and in the worst case. Earlier is likely.

And the prototype Centauraus engined Tempest II flew on 28 June 1943. Contract ACFT/2439/C.23(a) for 300 Tempest I to be built by Gloster, was switched to Bristol and changed to Tempest II. 30 built by Bristol, parts for another 20 sent to Hawker Langley for completion and 30 fuselages for ground tests with remainder cancelled at end of the war. Additional contracts for another 330 also cancelled.

The contracts were transferred to Bristol on 1 Aug 1943 for production at the shadow factory at Old Mixon, Weston-super-Mare. The first aircraft flew on 4 Oct 1944. Deliveries to RAF MU from 3/45 with service entry with 183 & 247 squadrons from Aug 1945.

 

[don4331]

The Supermarine 324-327 warrants a very careful examination.

That does not look like a very thin wing and these designs were being worked on without a lot of knowledge of high speed flight, much like the P-38.
Possibility of compressibility problems?
Also while the provision of Fowler flaps was forward thinking the implementation may have been a bit off. For flaps (or leading edge slats) to do the most work they needed to be applied over the most wing they can be used on.

One source claims the Supermarine flaps were only between the engines and the fuselage?
Could be wrong.
Another source claims fuel capacity was 220imp gallons?

Given Westland and Supermarine were responding to the same spec; that both have similarities e.g. Fowler flaps.
As the Whirlwind only has 134 imp gallons of fuel; Hurricane 97 imp gallons, the 324 having 220 is above average.
You can't go much thinner on the wing and still have space for those wheels to retract into.

The more flap/slat you have the more benefit is true, but they also add weight/complexity. If you can meet the take off/landing requirement with only inboard flaps, it leaves the outboard area clear for radiators and ducting & fuel cells.

Actually in '37, the ramp head Merlin is still having all sort of issues, and RR is hedging its bets with an up-rated Kestrel just in case Merlin is a dud. They switch back to the "bathtub" head and the rest is history, but it wasn't clear at time.

 

[EwenS]

I wouldn't say was an art, but it is one of the most difficult deflection shots:

As there were practically no mechanical aids, you are relying on the Mk. 1 eyeball and brain, to identify the ship correctly - e.g. Bismarck and Admiral Hipper classes are very similar in shape yet the BB is much larger, which is confusing when estimating range; the speed of the ship, the angle between the ship and you. Then you need to fly your plane to the correct position ahead and abeam, making sure you aren't turning, skidding or rolling your bomber (which would upset the torpedoes gyros). All while under a barrage of AAA trying to kill you. And even if you get everything right, the target might perform evasive maneuvers or your torpedo has issue(s) and you miss.

So, yes, constant training was required and only the most talented could get it right.

I'm trying to find where I read the IJN aerial torpedo successful runners statistics: If I remember correctly, they went from good chance of successful runner at the 20m altitude/150kn speed to atrocious at the maximums. High performance aircraft have difficult time slowing down to those speeds, and slowing down early to ensure they are at those speeds when required puts your fast airplane at same risk to CAP/AAA as the low performance aircraft - so why risk a more expensive plane?

Torpedo bombing is right up there with attacking a rhino with a spear.

Britain invested heavily in improving the skills of its TB pilots.

In 1940 the RN asked Fittups Ltd of Manchester, which was a supplier of theatre equipment and had worked with the RAF producing painted scenery for Link Trainers, to help develop the Torpedo Attack Trainer, a synthetic aid to train torpedo bomber pilots in dropping their weapons. It was based around a Link Trainer with a lighting arrangement to project all kinds of light conditions onto a screen.

They were installed at RN torpedo bomber training stations like Arbroath and Crail, where the remains of one can still be seen. It was later adopted by the RAF and adapted for use in training destroyer, MTB and submarine personnel.

THE TORPEDO ATTACK TRAINER AT ARBROATH FLEET AIR ARM STATION. 20 TO 23 JULY.

View of the Torpedo Attack Trainer, directly in front of the plane is seen the ship which is projected onto the screen.

www.iwm.org.uk

THE TORPEDO ATTACK TRAINER AT ARBROATH FLEET AIR ARM STATION. 20 TO 23 JULY.

View of the Torpedo Attack Trainer, directly in front of the plane is seen the ship which is projected onto the screen.

www.iwm.org.uk

And there was also the F director or Type F sight that was included in the equipment of aircraft like the Barracuda. This was developed by the RAF from 1937. The pilot pointed the aircraft at the target ship, fed in range and speed data etc, and the sight / director set the deflection needed on the torpedo. This superseded the crude arrangement of a sighting bar in front of the cockpit of aircraft like the Swordfish and Albacore, with the pilot doing all the maths involved.