January 1936: build your RAF

[Shortround6]

The Warwick was a stretched Wellington as it was. There were about 6 ft of fuselage plugs and a new wing center section that pushed the old Wellington outer wing panels out for about 10ft more wingspan. This made for a rather cheap and easy way to get a bigger bomber. It was let down by the lack of large engines to power it. With the cancellation of the Vulture, the late arrival of the Sabre and the much delayed Centaurus the first few hundred were powered by P W R-2800s which were bit under powered for the job. There were also control issues, especially with one engine out (fin and rudder too small?).
Trying for a 4 engine version would mean almost a whole new wing. The center section to hold 4 engines might push the old outer wings out too far (and/or they won't be strong enough to hold the higher weight) meaning they (and the ailerons have to be modified).
I am not sure of the bomb bay details but obviously a longer but not deeper or wider bomb bay than the Wellington was not what was wanted from 1943 on. You also have the fact that if you keep the old wing you are dealing with a pre 1936 airfoil which is going to be looking a bit dated by 1943, if you are going to build a new wing why not use a newer/better airfoil?

 

[merlin]

The thing is, you are describing the Whitley and Wellington. You could come up with alternatives to B.12/36 (Stirling) and P.13/36 (Manchester and HP.56). B.12/36 also produced the Supermarine heavy bomber (Type 316, then 317), construction of which was cancelled after Woolston was bombed during the war, which destroyed work on the aircraft, leaving the troublesome Stirling. Firms that conceived bombers to this include AW, whose design looked a bit like a four engined Whitley, the Boulton Paul design was technically advanced, Bristol and Vickers. The Air Ministry stated that this spec was (quote) "of outstanding importance..." and were happy with the Short and Supermarine designs, but the death of Mitchell left a bit of uncertainty in their minds, leaving the S.29 as the favoured aircraft. Because of Short's haphazard means of manufacture - although common to most British firms, the Stirling took a long time to conceive and was plaqued with production issues and wasn't that great a performer when it did get into service, so perhaps a better Stirling?

Regarding MPA, perhaps a long range four engined aircraft from scratch?

I'd stick to the Boulton-Paul design, it was favoured, until Supermarine did a bit of lobbying! This enables Shorts to continue with Sunderland production, and go to the a proper military version of the 'G' Class flying boat.

 

[yulzari]

Trying for a 4 engine version would mean almost a whole new wing.

Would this have not also have applied to the Manchester to Lancaster and the 2 to 4 engined Halifax?

Vickers had already committed to the geodesic construction system and stayed with it into the Windsor so any Vickers heavy bomber has to be geodesic and the Warwick is an easy step from the Wellington without necessarily competing for engines until production allows for Hercules/Merlin Warwicks.

 

[Shortround6]

Would this have not also have applied to the Manchester to Lancaster and the 2 to 4 engined Halifax?

Vickers had already committed to the geodesic construction system and stayed with it into the Windsor so any Vickers heavy bomber has to be geodesic and the Warwick is an easy step from the Wellington without necessarily competing for engines until production allows for Hercules/Merlin Warwicks.

The 2 engine Halifax never existed except on paper so you aren't throwing away anything in tooling/jigs/fixtures.

With Avro it was also a question of design or new wing or maybe build Halifax's.

The Warwick was supposed to be an easy step up but the engines failed (all of 4 of them), and the Warwick turned out to be less than satisfactory in any case. Trying to make a 4 engine version requires more work (what else gets delayed?) and if you start with low powered engines you don't get a very capable bomber. You get the Drag of 4 engine Lancaster or Halifax but with 60-75% of the power.

 

[yulzari]

Certainly the Warwick would be less capable than a Lancaster but Vickers commitment to geodesic construction means that the alternative to 4 engined Warwicks was 2 engined Wellingtons, which was what we actually used.

IIRC the structure of a geodesic framework can be strengthened by increasing the depth of the members, the thickness of their material or the density of the net. Any of these only require a new set of forming jigs. Even the Wellington managed to use some of the Wellesley jigs and the huge redesign of the prototype used mostly the same jigs. This was one of the sales points of the system to Vickers. A 4 engined Warwick was doable and within a timescale that could have seen it into service before the Stirling. After all, the Wellington and Warwick were designed together.

More Lancasters would indeed be better than 4 engined Warwicks but that would not have been the choice. The choice is Wellington or Warwick. A Warwick designed to take any of the 1,000bhp existing units would be a flexible production option using Bristol Pegasus, Wright Cyclone, P&W Twin Wasp, Bristol Taurus, Napier Dagger, Armstrong Siddeley Tiger, Rolls Royce Merlin, Bristol Hercules as might be available.

 

[tomo pauk]

I'd leave the Hercules and Merlin for other heavies, though.

 

[Shortround6]

More Lancasters would indeed be better than 4 engined Warwicks but that would not have been the choice. The choice is Wellington or Warwick. A Warwick designed to take any of the 1,000bhp existing units would be a flexible production option using Bristol Pegasus, Wright Cyclone, P&W Twin Wasp, Bristol Taurus, Napier Dagger, Armstrong Siddeley Tiger, Rolls Royce Merlin, Bristol Hercules as might be available.

You are bouncing from 1100lb engines to 2000lb engines and from 1000hp hp or less to 1200/1300hp in 1940 to 1700hp in 1943/44. Expecting an airplane to perform close to the same with all those engines is a bit much

as in a plane designed to use 1300hp engines is going to under-powered and hard to take-off and climb out with 900-1000hp engines unless you really restrict teh bomb and fuel load and if you do, what's the point of making it?

and if you design the plane for 900-1000hp engines and try to add 1300-1400hp engines later you are adding a couple of tons of power-plant weight. This also affects bending stress in the wings and other things aside from simple weight calculations.

And three of them probably should have never seen service, two for sure. The Tiger was nothing but trouble in it's later Versions. The Whitley was re-engined as fast as possible. The Dagger might have been OK in it's MK III 800hp version but not much good can be said of the 1000hp MK VIII. The Taurus might have been OK in the Albacore but was never a really good engine in the Beaufort. It got better as time went on but by the time it got better there were much better alternatives.
You also don't have an unlimited supply of engines of any type. Especially in 1939/40/41. P W 1942 production of R-1830s was over 12 times what their 1939 production had been.
The real Warwick was rather curtailed in Production because of P W slow delivery of R-2800 engines, by the time they thought they would get 200 engines they had only gotten 80. The British had planned to switch the Beaufort to R-1830s until the ship carrying the first 200 engines was torpedoed. Faced with a delay of months (P W didn't have 200 more engines sitting in a warehouse, replacement engines would have to be drawn a few at time from the production or some other aircraft program would be looking at dozens if not over a hundred airframes with no engines).

The Americans got away with 1200hp heavies in part due to the turbo-chargers which allowed for cruise settings of around 700-750hp lean and 1000-1100hp max continuous at any practical altitude, or thousands of feet higher than non-turboed engines would provide the same power. Due to the thinner air this meant more speed for the same power ( or less power for the same speed which means more range).

Sticking a Hercules on a Plane designed for Pegasus engines is like sticking R-2600s on a plane designed for R-1820s.

 

[yulzari]

Good thing nobody replaced the Pegasus with Hercules on the Wellington or Tigers with Merlins on Whitleys then. Let alone replacing Taurus with Hercules or Merlins when using Beaufort wings (which were themselves oversized Blenheim wings) on Beaufighters.

I do note that replacing x2 2,000bhp with x4 1,000bhp motors is not quite the same. In the Warwick you are replacing the Sabre, Centuarus, R2800 x2 with the list above x4.

The comparison has to be between the Wellington and Warwick. They are the only two possibilities for Vickers to make.

BTW When De Havillands engine department were asked to comment on the Napier Dagger they found that the Napier standard baffling simply had too little exit capacity and increasing this let the Dagger cool itself quite adequately. Too late though.

However, I think we have been over this ground before and agreed to differ.

 

[Shortround6]

Did they beef up the landing gear in the later versions of the Wellington? Or have to change anything else?

Wellington Prototype, tare 18,000lbs, all up 24,850lbs
Wellington Mk IC, tare 18,556lbs, All up 28,500lbs
Wellington Mk X, tare 22,474lbs, all up 36,500lbs

Tare weight does NOT include guns although it may include the turrets.

Whitley Mk II III, (tiger engines) tare weight 15,475lb, all up 22,990lbs
Whitley MK V (Merlin) tare weight 19,350lbs, all up 33,500lbs.

Granted more was changed than just the engines but each of those planes picked-up about 2 tons tare weight with the new models, and 4-5 tons all-up.

You may need heavier landing gear and tires, different brakes and other modifications. Sticking the bigger parts on the lower powered early versions gives you a not very useful airplane.

BTW, the Beaufort used different wing construction than the Blenheim. Light alloy extrusions and forgings in places instead of steel plate and angle stock. The wing was both lighter and stronger.

One might also note that seldom, if ever, were older models of aircraft 're-engined' to bring them up to "new" standards in the field.

The Dagger, even if De Havillind was right, doesn't get you much. The 1000hp was at 8750ft. Better than the Taurus's 3500ft FTL but hardly what you want for a 4 engine heavy bomber. Take off was 955hp.
The Pegasus engines used in the Wellington were good for 965hp take-off( had to be restricted with 87 octane fuel), had 1000hp at 3,000ft in low gear and 885hp at 15,500ft in high gear.
The Dagger was about 200lbs heavier per engine.

 

[yulzari]

So the argument is that we would be better off with Wellingtons?|

 

[Shortround6]

Well, in 1938-40 you are going to get 2 Wellingtons for every 4 engine Warwick from an engine standpoint.

Work on a 4 engine Warwick may delay improvements to the Wellington. 2 engine Warwick was delayed at times due to work being done on the Wellington and it shared a lot more structure.

EVERY engine change is going to require hundreds if not thousands of hours of drafting work for different firewalls, engine mounts, exhausts, cowls, control mechanisms accessories and piping. Things as simple as fuel and oil lines are going to different from the firewall forward. It isn't hard work but each engine installation needs a full set of drawings and that means time.

A bomber using 4 Pegasus or 4 Daggers or 4 other small and/or low powered engines (the R-1830s being delivered even in early 1940 were not 1200hp versions,1200hp Wright R-1820s don't start showing up in production planes until the summer /Fall of 1940) is not going to give you any real big operational advantage. It serves as little more than 'getting your feet wet".
The first 86 Halifaxes used Merlin X engines and nobody was particularly happy with them. Even switching to the Merlin XX still left problems until the allowable boost was increased.

The RAF was short of all sorts of combat aircraft in 1938-41, trying to introduce low powered 4 engine bombers isn't going to solve much and once high powered engines are available they would be better used in a more modern airframe.

 

[tomo pauk]

Shouldn't the 2 'Warwick 4s' carry about the same payload to about same distance as 4 Wellingtons, in case both are outfitted with similar engines? Conversely, the 'W 4' will be able to reach a target that is beyond Wellington's range.
We also need to train less crew for 1 'Warwick 4' than for 2 Wellingtons.

 

[yulzari]

My line of thinking is this. Vickers are committed to geodesic construction and changing to stressed skin will almost mean closing the factories and equipping brand new ones and re training staff. The only designs are Wellington, Warwick (and later Windsor).

Which would be the best choice to use? IOTL Vickers made Wellingtons until five months after the war ended.

Wellingtons used Bristol Pegasus, Rolls Royce Merlin and Bristol Hercules (not counting post war jet and turboprop test aeroplanes).

Warwicks were to use Rolls Royce Vultures, Bristol Centaurus, Napier Sabre or Pratt Whitney R-2800

Ironically Vickers modernised the design type into the stressed skin Viking airliner (including the worlds first jet airliner single test type) Valetta military transport and nosewheel Varsity trainer (which had a pannier bomb bay for practice bombs)which last served in 1992 at RAE.

 

[Shortround6]

When are these things supposed to go in service?

The first Wellingtons reach a squadron in Oct 1938, By Sept 1939 8 "operational" squadrons had received Wellingtons (not sure if all squadrons had full compliments) but not all were actually declared operational by day and none were operational by night. 2 more squadrons were held in 'reserve' and and another one was conducting crew training. In late 1940 Wellington IIs were being issued to some squadrons to replace Fairey Battles. This rather points to need for a comprehensive plan. Build Warwick 4s so you build fewer Wellingtons so you can use Battles and Blenheims in greater numbers for longer?

The First Wellingtons had crap Vickers "turrets" or powered gun mounts which did NOT traverse even 180 degrees and a retractable ventral 'dustbin'.
Same armament on the 'Warwick 4' ?

And until you figure out the navigation problems it doesn't really matter which bombers you use. Miss the target city with 200 Wellingtons or with 100 Warwick 4s?

For an interesting "snap shot" of the planes Britain was using and planned to be using the article from Nov 1937 is rather interesting, granted it is what information could be released to the public and is trying to paint a rosy picture.

1937 | 3235 | Flight Archive

We have the advantage in hindsight of knowing exactly when the war would start and what problems they hadn't solved yet and how long it took to solve some of them.

 

[tomo pauk]

In case Vickers is really capable to move fast from production of Welington to production of 4-engined bomber, 1941 seem like realistic proposition? Once Wellington is to receive powered turrets and Hercules engines, the ratio between 'producible' 'Warwick 4' and Wellington moves from 2:4 to 3:4? The 'W4' will have far better flying capabilities in engine-out situation - less aircraft crews lost. Having the 'W4' in production by 1944 would be a better proposal than having Wellington by that date.

Going by the original premise of this thread, Battles would be produced in quantity of 700-800, rather than 2000+ examples. Fairey can build Hampden instead? The non-development/production of Botha leaves Blackburn to produce, say, Perseus Blenheim, or Hampden, or Whitley?

 

[Shortround6]

I am not sure what the Warwick 4 really gets you. Trying to turn a 1938/39 Warwick 4 with Pegasus engines into a 1944 Warwick 4 with 1700hp Hercules engines is going to take a bit of modification all on it's own and are you really going to wind up with a plane any better than a Halifax III or a Lancaster?

Granted with hindsight we can specify different bombays than the Wellington, Warwick, Sterling and Halifax used so as to get more 4000lbs and such but ALL the early bombers had problems with the bomb bays when they changed the type/s of bomb/s they wanted to use.

You might also try comparing tare weights to see what the ratio of aircraft might be. Late Wellingtons went about 22,500lbs , the Warwick 2 went about 29,000lbs, the Halifax went about 36,000lbs ( Melrin X engines) to 39,000lbs (Hercules)
While the Short Stirling with it's oversized fuselage went 43,000lbs.
The Manchester was 26,760lbs while a Lancaster went about 36,450lbs.
Those are weights without guns, ammo, radios etc.

You are not going to get 3 four engine bombers for 4 two engine bombers.

We have been over the Battle before, while perhaps more were made than really needed cutting production by 1400-1500 leaves you woefully short of aircraft to equip active squadrons late 1039/40 and really up the creek without a paddle for crew trainer aircraft from 1940 on.

We also need to check to see what some of these "alternative" factorys were actually doing before deciding they could just build plane XXX.

For instance Blackburn built over 1700 Swordfish, first one delivered Dec 29, 1940, they built 635 Barracudas and one of their factories built 250 Sunderlands at about 60 per year. Fully occupying that factory.
Blackburn was also appointed as the 'sister' company to Grumman and handled (with the aid of sub contractors) ALL of the modifications to American Naval aircraft used by the British. Installations of British radios, IFF, oxygen equipment, catapult spools, rocket launchers, and so on.

Also please consider it can take 6 months to a year from first production aircraft to building them at a good rate in a given factory.

The need for suitable training aircraft (or even barely suitable) cannot be under estimated either. Perhaps too many crews were lost in training and certainly too many were lost using unsuitable operational aircraft and unsuitable tactics but shorting the training squadrons puts you in the same situation the Germans and Japanese found themselves in. Poorly trained crews, even with good planes, do NOT achieve good results.

British tried some specialized training aircraft but some came up short;

First flight 18 June 1937 but the order for 250 was cut to only 50 with the last 20 being delivered as engine-less air-frames for ground instruction.

 

[Juha]

...
For an interesting "snap shot" of the planes Britain was using and planned to be using the article from Nov 1937 is rather interesting, granted it is what information could be released to the public and is trying to paint a rosy picture.

1937 | 3235 | Flight Archive

We have the advantage in hindsight of knowing exactly when the war would start and what problems they hadn't solved yet and how long it took to solve some of them.

Thanks for a very interesting link but I must say that the recognation of the foreign national markings has been abysmally poor in 37 at the Flight office, the Gladiator is Latvian, not Finnish and the Anson is Finnish not Swedish.

 

[tomo pauk]

I'm not sure what part is devoted to yulzary and what to me, but at any rate:

I am not sure what the Warwick 4 really gets you. Trying to turn a 1938/39 Warwick 4 with Pegasus engines into a 1944 Warwick 4 with 1700hp Hercules engines is going to take a bit of modification all on it's own and are you really going to wind up with a plane any better than a Halifax III or a Lancaster?

'My' Warwick 4 will still remain on Pegasus and similar engines. It would be better than Wellington that was produced by 1944 and used until war's end.

Granted with hindsight we can specify different bombays than the Wellington, Warwick, Sterling and Halifax used so as to get more 4000lbs and such but ALL the early bombers had problems with the bomb bays when they changed the type/s of bomb/s they wanted to use.

Agreed.

You might also try comparing tare weights to see what the ratio of aircraft might be. Late Wellingtons went about 22,500lbs , the Warwick 2 went about 29,000lbs, the Halifax went about 36,000lbs ( Melrin X engines) to 39,000lbs (Hercules)
While the Short Stirling with it's oversized fuselage went 43,000lbs.
The Manchester was 26,760lbs while a Lancaster went about 36,450lbs.
Those are weights without guns, ammo, radios etc.

Thanks for the numbers. Hopefully the Pegasus-powered 'W 4' will be somewhere around 30,000 lbs, under same conditions. Vs. the Merlin heavies, we save 2500-3000 lbs on powerplant weight alone.

You are not going to get 3 four engine bombers for 4 two engine bombers.

Depends what is compared. Cost of the B-26 and B-17 was about the same, what B-17 was capable to do was beyond B-26s capabilities. If we want to field two B-26s instead of one, we need twice the number of crew, for example. What most of major countries lacked was trained manpower, not equipment.

We have been over the Battle before, while perhaps more were made than really needed cutting production by 1400-1500 leaves you woefully short of aircraft to equip active squadrons late 1039/40 and really up the creek without a paddle for crew trainer aircraft from 1940 on.

For 1939-40 - RAF (and other powers) need a bomber that is a bit more of a target practice for enemy fighters and AAA. Unfortunately, Battle was that, Ju-87 joined to the list shortly after, later the Su-2 joined, closely followed by Japanese and some US s/e bombers. Expecting from a single MG to defend a bomber is, well, silly, especially if one wants ones fighters to carry in the air a battery of MGs, or even cannon(s).
RAF can train their crews on Ansons, along with plenty Miles and US-built trainers at 1st, then switch to, indeed, Battles and other more worthy planes.

We also need to check to see what some of these "alternative" factorys were actually doing before deciding they could just build plane XXX.

For instance Blackburn built over 1700 Swordfish, first one delivered Dec 29, 1940, they built 635 Barracudas and one of their factories built 250 Sunderlands at about 60 per year. Fully occupying that factory.
Blackburn was also appointed as the 'sister' company to Grumman and handled (with the aid of sub contractors) ALL of the modifications to American Naval aircraft used by the British. Installations of British radios, IFF, oxygen equipment, catapult spools, rocket launchers, and so on.
Also please consider it can take 6 months to a year from first production aircraft to building them at a good rate in a given factory

Thanks again for the info.
Blackburn also built 580 Bothas. With those deleted from design and production, Blackburn can start building stuff that is already designed tested, like indeed they were doing with the A/C you've listed. In case the 'better Blenheim' is chosen instead of Bothas, they can build more of the former.

The need for suitable training aircraft (or even barely suitable) cannot be under estimated either. Perhaps too many crews were lost in training and certainly too many were lost using unsuitable operational aircraft and unsuitable tactics but shorting the training squadrons puts you in the same situation the Germans and Japanese found themselves in. Poorly trained crews, even with good planes, do NOT achieve good results.

British tried some specialized training aircraft but some came up short;

First flight 18 June 1937 but the order for 250 was cut to only 50 with the last 20 being delivered as engine-less air-frames for ground instruction.

Agreed. Miles-built stuff seem like real winners.

 

[Aozora]

'My' Warwick 4 will still remain on Pegasus and similar engines. It would be better than Wellington that was produced by 1944 and used until war's end.

What sort of armament would a Pegasus powered Warwick 4 be able to carry? Bomb load? Projected operational gross weight? Projected operational height at POGW? The Pegasus XVIII, which would have been the most powerful Pegasus available in 1944, put out 1,065 hp maximum at take off and 965 hp @ 13,000 ft on emergency power ratings; it had a maximum economical cruise rating of 585 hp @ 20,000 ft (100 octane fuel). Without a decent supercharger or turbocharger there is no way the Pegasus could have provided a four-engined bomber with anything other than mediocre performance, at best:

Thanks for the numbers. Hopefully the Pegasus-powered 'W 4' will be somewhere around 30,000 lbs, under same conditions. Vs. the Merlin heavies, we save 2500-3000 lbs on powerplant weight alone.

This would imply a maximum operational weight of c. 58-63,000 lbs? So the power loading at take-off (1,065 hp x 4 = 4,260 hp) at maximum gross weight would have been somewhere between 13.6 and 14.7 lbs/hp (Lanc at 68,000 lbs = 13.3 lbs/hp approx, Halifax III at overload of 65,000 lbs = 12.7 lbs/hp)?

A Warwick W4 might be marginally better than a Wellington by 1944, but it would still have been thoroughly obsolete for front-line BC duties, especially for the daylight raids BC increasingly mounted post mid-1944.

 

[Shortround6]

The Pegasus stayed pretty much status quo for the duration of the war. All the development was going into the sleeve valve engines. The Pegasus was actually a pretty good engine but nothing you would want to design a 4 engine heavy bomber around given that you KNOW it doesn't get any better.
The Halifax I was something of a dog with Merlin X engines. With Merlin XX engines it's ceiling and cruising heights improved by 3,000ft or so. It got even better with the switch to the Hercules engines but that wasn't until Jan of 1944.
Building Warwick 4s with Pegasus engines in 1944 might give you a better Air-sea rescue plane but it would be a pretty lousy bomber.

Compare it to a Y1B-17

"Four Wright R-1820-39 Cyclone radials rated at 930 hp for takeoff, 850 hp at 5000 feet, 775 hp at 14,000 feet. Performance: Maximum speed 256 mph at 14,000 feet. Landing speed 70 mph. Cruising speed 217 mph at 70 percent power. Service ceiling 30,600 feet. An altitude of 10,000 feet could be attained in 6.5 minutes. Normal range 1377 miles. Range with 4000 pounds of bombs was 2400 miles and 3320 miles with no bombs. Dimensions: Wingspan 103 feet 9 3/8 inches, length 68 feet 4 inches, height 18 feet 4 inches, wing area 1420 square feet. Weights: 24,465 pounds empty, 34,880 pounds normal loaded, 42,600 pounds maximum. Armament: Armed with five 0.30-inch machine guns with 1000 rpg. One gun was mounted in each of nose, dorsal, ventral, and two waist positions. A maximum bombload of 8000 pounds could be carried in an internal bomb bay."

From Joe Baugher's web site. Now I will note that the engines in these early planes were never given a military rating and the powers at altitude given are the MAX Continuous power or pretty close to the climb powers in the chart provided by Aozora. They did NOT have turbos. They also weighed just under 1200lbs or very close to what the Pegasus weighed. The engines were "G" series engines, not "G-100" or "G200" engines. Later B-17s got the G-200s which weighed about 115-125lbs more (plus turbo).
Perhaps the Pegasus could have been developed but it would have gained weight, (just like "H" series R-1820s gained even more weight than the G-200s).The planes power to weight ratio will get better but those 4 big radials (Pegasus was about the diameter of the R-1820 or the R-3350) are never going to be as streamline as a V-12 engine.

Please notice the defensive armament and the speed. Five hand held .30 cal guns are never going to be good enough to operate in daylight (or even moonlight and given the somewhat streamline gun positions compared to early British turrets,leaving the guns home and plating over the openings isn't going to get you enough speed to escape the enemy fighters. The Y1B-17 being fairly well streamlined compared to British bombers to begin with.

Add picture of Halifax MK I: