Worst British twins, and how to fix?

[Thumpalumpacus]

Has anyone actually tried?

You get a smear.

Don't ask any more.

 

[Frog]

The British had some twin engined, ICE-powered aircraft that were duds, such as the Avro Manchester. I would include in these the following:

Blackburn Botha
Armstrong Whitworth Albemarle
Saro Lerwick
Blackburn B-20

With effort the twin-engined Manchester was made into the superlative four-engined Lancaster. What can we do to get other British ICE-powered twin-engined duds into successful territory?

The same as with the Manchester : make them four engined.

 

[yulzari]

Beaufort: fix the damn Taurus (this was done by the time the Albacore enters service)! Otherwise, fit US Twin Wasp engines as the Australians did.

They did try to do that and the engines still exist. Sadly over a mile down in the North Atlantic. There are risks in relying upon imported machinery in wartime from a whole ocean away.

 

[Admiral Beez]

It appears the run of less than inspiring designs comes about with George Petty's ascendency as Blackburn's chief engineer, beginning with the Skua, which wasn't a terrible aircraft but was bigger than it needed to be. Petty was also responsible for the Botha and Firebrand.

Agreed, the Skua is needlessly larger, over 2ft longer, with a 5 ft wider wingspan than the SDB Dauntless. And unless coerced by the Air Ministry, what the heck was Petty thinking with the Roc.

Where was the future Buccaneer's designer Barry Laight during this time of failure at Blackburn?

 

[bf109xxl]

The same as with the Manchester : make them four engined.

That's what I always tell my wife at the store, that four beer packs are much better than two!

 

[Shortround6]

Agreed, the Skua is needlessly larger, over 2ft longer, with a 5 ft wider wingspan than the SDB Dauntless.

Well, the 2ft was a screw up in the CG,

Fixed by moving the engine 2 feet further forward, at the cost of the view over the nose.
as far as the wing goes, The Skua had a folding wing so the larger wing was not a problem for deck handing, elevator space/size or hanger space. May have been a speed problem.
On the other hand British carriers had small flight decks. Maybe they needed the extra lift for take-off/landing?

And unless coerced by the Air Ministry, what the heck was Petty thinking with the Roc.

Define "coercion".
You want the order for 136 planes you build kind of what the Air Ministry wants or they order the planes from Boulton Paul. Not sure if performance was at the forefront or if cheap (Skua parts) and use engines not wanted by anybody else was leading the list of requirements. Strangely enough B-P did all (or most) of the construction under sub contract.

The Air Ministry had a quite a lot of input into designs. If the designer/company doesn't meet the "requirements" they don't get the contract. Declining the contract because it means a rubbish aircraft may have been patriotic but but your unpaid workers and shareholders are not going to be happy and not necessarily in that order.
Blackburn was "told" to use the Perseus engines in Botha, Mercury's were going to Blenheim's (not enough power anyway) and the Pegasus engines were going to Wellington and Hampdens and Sunderlands. Bristol managed to snag the Taurus engines for their own Beauforts but everybody knew the Botha was in trouble when they were told to change from a 3 man crew to a 4 man crew with larger fuselage. Nobody knew how much trouble. But if Blackburn kept the 3 man fuselage.................................no contract.

 

[Admiral Beez]

The Air Ministry had a quite a lot of input into designs. If the designer/company doesn't meet the "requirements" they don't get the contract. Declining the contract because it means a rubbish aircraft may have been patriotic but but your unpaid workers and shareholders are not going to be happy and not necessarily in that order.

Fairey was smart pre-war with the Swordfish. Take a gamble and make what you think the market will want, not what the government has specified, and then proceed to knock the assumed leader in biplane TSRs, Blackburn with their Shark out of the market. Were any other British warplanes created thusly, where the Air Ministry's official Specification was a mere formality to accept an aircraft that already exists? I guess this is trickier during wartime where there's no time for blue sky projects.

And if you're Blackburn and the Air Ministry tells you to make what becomes the Botha, why would you purposely make it shite with regards to visibility and stability? At least put your best foot forward.

 

[special ed]

View: https://www.youtube.com/watch?v=yiJ9fy1qSFI

How isolated and bored were the first people to try this? I have seen monkeys in cages do similar.

 

[WARSPITER]

At least monkeys have some fun by throwing it at each other.

 

[EwenS]

The Lerwick was found to be troublesome from the outset, aerodynamics-wise, both the manufacturer and the Marine Armaments Experimental Establishment agreed on its poor qualities. The only solution is to end production early on and task Saro with production of the Sunderland, which was already in production and service by the time the war begins.

.

Another case of the sudden rush to rearm from 1936. A contract for 21 (3 prototypes and 18 production aircraft) granted straight off the drawing board. Deliveries from Nov 1938 to May 1941. While the follow on contract for a further 31 production aircraft was cancelled (probably on 24 Oct 1939?), the initial contract was allowed to be (had to be?) completed.

At the same time as it was developing the Lerwick, it was also developing a Sunderland competitor, the A.33 for which it held a production contract for 11 aircraft, which flew for the first time in Oct 1938, only to be wrecked 11 days later. Development then ceased allowing SARO to concentrate on the Lerwick.

Maybe if the company's design effort could have been concentrated on the Lerwick from the outset it might have turned out better.

SARO then took over production of the Supermarine Walrus and its successor the Sea Otter (first contract issued 25 Jan 1940). That move freed up Supermarine design and production capacity to concentrate on Spitfires. Given the close proximity of these two companies factories, this probably helped a smooth transfer.

It also opened a factory at Beaumaris on Anglesey which devoted its efforts to modifications to, and maintenance of the RAF Catalina fleet from 1941. Their next project was for a Sunderland successor, where they were teamed with Shorts to design the Shetland.

As for the Sunderland, Blackburn's Dumbarton factory launched its first Sunderland (Mk.II serial T9083) on 1 Nov 1941. These succeeded the Botha on the production line, and at least didn't need ferried upriver for flight test at Abbotsinch (today's Glasgow airport). Short & Harland produced its first in April 1942 while the Short shadow factory on Windermere produced the first of its 35 in Sept 1942.

 

[BarnOwlLover]

Fairey was smart pre-war with the Swordfish. Take a gamble and make what you think the market will want, not what the government has specified, and then proceed to knock the assumed leader in biplane TSRs, Blackburn with their Shark out of the market. Were any other British warplanes created thusly, where the Air Ministry's official Specification was a mere formality to accept an aircraft that already exists? I guess this is trickier during wartime where there's no time for blue sky projects.

DH Hornet, Hawker Fury/Sea Fury. Both began as private ventures that the RAF/RN picked up, though they didn't enter service until after the war. The Mosquito also applies here as a private venture the RAF picked up.

 

[EwenS]

Fairey was smart pre-war with the Swordfish. Take a gamble and make what you think the market will want, not what the government has specified, and then proceed to knock the assumed leader in biplane TSRs, Blackburn with their Shark out of the market. Were any other British warplanes created thusly, where the Air Ministry's official Specification was a mere formality to accept an aircraft that already exists? I guess this is trickier during wartime where there's no time for blue sky projects.

Except that is not what happened.

Back around 1930 various Specs had been raised, firstly for a torpedo bomber (Blackburn submitted a design for this amongst other companies) and secondly a torpedo spotter recce type (which Fairey amongst others responded to). Both Blackburn & Fairey received contracts for prototypes but without production contracts following.

Then in 1933 S.15/33 was issued combining and amending the two previous Specs. Blackburn, Fairey & Gloster replied. By that time Fairey, encouraged by Admiral Clive Rawlings, had built on its previous experience to build the TSR.I (which crashed) as a private venture. BUT Blackburn had also built the B.6 as a private venture building on its past experience. Sturtivant notes that S.15/33 had been virtually written around the Fairey proposals.

Blackburn B.6 first flight 26 Aug 1933. Production contract awarded Aug 1934 for an initial 16. Entered service May 1935. Further contract for 53 issued June 1935 with another in 1936 for 95. Production ended after a final batch for Canada with a total of 269 produced. Withdrawn from frontline units in Sept 1937, but continued in second line service to 1944. Main problem was the Tiger engines.

Fairey TSR I first flew 10 July 1933. Crashed 11 Sept during spinning trials.

Fairey TSR II redesign based on test data from TSR I. First flight 17 April 1934. Following more development work a production contract was issued on 23 April 1935 for 3 pre-production aircraft. First flight of these was 31 Dec 1935. Production order followed with first batch of 86 produced Feb-Sept 1936, with more batches following until Fairey built the last of 692 at the beginning of 1940. Service entry was July 1936.

The ultimate irony is of course that production was then moved to Blackburn, who went on to build 1,700 Mk.I/II/III "Blackfish"

 

[Shortround6]

One can also see in the 30s that some airframe manufacturers that had an associated engine company tended to favor that companies engines, sometimes to the detriment of the airplanes.
Another difference is that there was fine line between being steady and easy to fly on long missions in bad weather and being nimble/maneuverable in combat (taking evasive action) and the bias tended to go back and forth a bit.

 

[Admiral Beez]

One can also see in the 30s that some airframe manufacturers that had an associated engine company tended to favor that companies engines, sometimes to the detriment of the airplanes.

I think the lack of an airframe manufacturer was a detriment to Armstrong Siddeley. Not that Rolls Royce suffered as was.

 

[Shortround6]

I think the lack of an airframe manufacturer was a detriment to Armstrong Siddeley.

Wither the Armstrong Siddeley engines were good or bad in the 1920s may be up for argument. The Problem in the 30s was that A-S didn't make any significant improvements over the 1920s engines while most of the rest of world (or British companies) did.
A-S engines were sold to a bunch of little countries in the 20s and early 30s and airframe builders used what their customers wanted if they really wanted the A-S engines. But the A-S engines were falling behind in regards to reliability/durability. This was all taking place fairly rapidly. A number of WW I engines were lucky they could make 20-30 hours without overhaul and they often needed a top end job (and/or de-carboning) in 1/2 that time. With a duration of 1 -2 hours per mission this was doable. Getting engines to run for the 16 hour 27 minute flight by Alcock and Brown was part of the legend.
Armstrong Siddeley had been teamed up with Armstrong Whitworth from 1919 to 1927.
The A-S engines were OK for trainers but high power eluded them. 1939 engines were much improved over 1931 engines and A-S was stuck in the early 30s.

The engine list in Wiki is impressive at first glance, however a lot of 5 and 7 cylinder engines used the same cylinders, the 10 cylinder engines were two 5s stuck together and most of 14 cylinder engines were two 7s stuck together and a some of the 5 & 7 engines didn't really change the cylinder sizes to any great extent.

Armstrong Siddeley Jaguar - Wikipedia

en.wikipedia.org

The root of the A-S problem was that the first engine, the Jaguar, was the result of war time work done at the Royal Aircraft Factory.
"The RAF.8 was the work of a design team lead by F.M. Green, and incorporated the findings of research into aluminium air-cooled cylinders by Samuel D. Heron and Professor A. H. Gibson" and at least Green and Heron (and a few others) left the government work and went to Siddeley, and over a few years, most or all left. Heron was one of the men who came up with Sodium cooled exhaust valve and a number of other improvements to engines and fuel.
Siddeley never came up with a substitute design team, or come up with one until it was too late into the 30s to get anything into production.
The Jaguar was a completive engine against early (1920s) Bristol Jupiter's, Fedden strived to improve things. Siddeley was more content to plod along although he tried harder than Napier in the 1920s. But it was more in the what could they make with the least investment in new tooling.

 

[Admiral Beez]

In 2022 I visited the London Science Museum and took a look at the Armstrong Siddeley Tiger. It's certainly a good looking engine, FWIW, and I believe is the only British production 14-cylinder radial with conventional poppet valves - albeit missing essential main bearings. They were on the right path and just needed more money to give Britain a poppet valve 14-cylinder radial equal to that of Curtiss or perhaps P&W. Perhaps had A/S skipped the dead-end Deerhound and instead pursued something akin to a British R-2800 Double Wasp the firm would have had a winner over the complex Bristol Hercules sleeve valve.

The Tiger's maintenance manual is interesting ARMSTRONG-SIDDELEY CHEETAH IX / TIGER VIII / LYNX IVC. DOWNLOAD or DVD | eBay

 

[Shortround6]

They were on the right path and just needed more money to give Britain a poppet valve 14-cylinder radial equal to that of Curtiss or perhaps P&W.

The basic engine was too small.
Unfortunately it appears that the designers were trying to be a bit too clever and missed or did not take the avenues of bigger and higher boost (and heavier construction).

KISS seems to have been ignored and the future was also overlooked. This is bit harsh but A-S had a plethora of projects going on behind the scenes. 11 or 12 of the Dog series engines were at least drawn/sketched with no more than 5 of any one type built. The normal engines were all named after Felines.
I mean, who needs a 14 cylinder 250hp two row radial engine?
A-S was already making engines that made little commercial sense. The 1928-1934(?) Serval was a 10 cylinder 2 row radial (5 per row) of about 340hp.
A-S never built an engine with 9 cylinders in one row. They tried a 15 cylinder 3 row and a number of 21 cylinder 3 row engines.

I don't know why.
They have had trouble with foundry issues. The engine in the London Science Museum is certainly a pretty engine with a lot of polish and fine fitting.
However high powered air cooled engines need a lot of fin area. Wright tripled the fin area on the 9 cylinder R-1820 between 1930 and 1940 and added a lot more fin area later for the 1300-1350hp engines. This requires different construction techniques and very different ways of building cylinder heads. If you don't have the machinery needed you can't build the engines like the Americans did, what you can draw on paper doesn't matter. It appears that the A-S Tiger cylinder head was cast, like many (or all) of the air cooled engines of the very early 30s. Some were forged, better casting techniques crossed into forging. Forged heads were stronger. P & W got to the point where they were taking the raw cylinder head forging (for one version of the R-2800) or casting? and drop forging it several times to get the rough shape they wanted and the grain structure. They trimmed excess material between stages, then they machined in most or all of the fins in final blank with ganged slitting saws. I think the raw cylinder head started at around 60lbs and when they got done it was down to about 15lbs (?).
Even in the late 30s A-S running their production engines on about 2 1/2 lbs of boost for 87 octane fuel so something was going on. Strength of different parts? cooling?

BTW;

Armstrong Siddeley ‘Dog’ Aircraft Engines

In the 1930s, Armstrong Siddeley started a new line of engines named after dogs (canines). Most of these engines were radials with banks of inline cylinders. The most famous engine of the series wa…

oldmachinepress.com

 

[wuzak]

The basic engine was too small.

It was 2,000 cubic inches, bigger than the Wright R-1820 and P&W R-1830.

Unfortunately it appears that the designers were trying to be a bit too clever and missed or did not take the avenues of bigger and higher boost (and heavier construction).

There were definitely design choices that limited the power the Tiger could produce.

I mean, who needs a 14 cylinder 250hp two row radial engine?

Possibly it was a product of its time, i.e. the early 1920s.

 

[Admiral Beez]

There were definitely design choices that limited the power the Tiger could produce.

I'm not suggesting A/S simply upscale the Tiger. But as Britain's only interwar poppet valve 14-cylinder radial it was a good place to start. So, A/S procures through some means a Pratt & Whitney R-1830 Twin Wasp and a Wright R-2600 Twin Cyclone and tear them down. AIUI, the biggest flaw on the Tiger was insufficient bearing surfaces. By 1938-39, the A/S Super Tiger or whatever is produced.

This would then lead to an equal of the 18-cylinder R-2800 Double Wasp. That'll get even a Botha moving quickly enough.

 

[Shortround6]

It was 2,000 cubic inches, bigger than the Wright R-1820 and P&W R-1830.

The too small was in response to
" They were on the right path and just needed more money to give Britain a poppet valve 14-cylinder radial equal to that of Curtiss or perhaps P&W." from Admiral Beez.
Curtiss's 14 cylinder engine was 2600 cu in.
The G-R 14 cylinder was 2360 C.I. as was the Hercules, the Soviet M-88, the and several others.
The P&W engines split, but they had adapted the 3 bearing from the beginning. The R-1535 was too small and only made due to the Navy's insistence. The R-1830 was good engine but was too small by the late 30s which is why P&W built the R-2180 before deciding that was too small and and changing to 18 of the same size cylinders to make the R-2800.

The British tried powering Wellingtons with R-1830s and the there was a proposal for an R-1830 Whitley but that was more desperation (lack of Merlins) rather than desire for improvement.
The Tiger was OK in 1932. OK in 1932 was not OK in 1936-37 and far from OK in 1939/40.

The Americans were not all powerful. The R-1830 stagnated for several years and only worked in the B-24 due to the turbo charger. P&W needed to figure out how to make new cylinders and new cylinder heads (and new bearings?) to get the engine up to 1350hp at the end of the war. The R-2000 DC-4 engine worked for transports but since they designed it sort of on the cheap side, the power gain over the R-1830 was mostly available at take-off/very low altitudes.

Trying to equal the American 2nd line engines in the late 30s is kind of low fruit.

There were definitely design choices that limited the power the Tiger could produce.

Some of the choices may have been out of the hands of the designers, limits imposed by plant tooling/facilities or by the plant/facilities of their suppliers/subcontractors.

Possibly it was a product of its time, i.e. the early 1920s.

The 250hp engine was the Whippet of 1935, it never got off paper. Somebody got smart. Building a 14 cylinder engine when they were developing a 270-330hp 7 cylinder at the same time was a waste of time.
I am not sure if there was a small multi cylinder disease that was sweeping British designers at the time or what was going on (or world wide?).
A-S Hyena 1933, 15 cylinder 3 row, 1615 C.I.
Napier Rapier, 1929, 16 cylinder H 4 banks, 539 C.I.
Napier Dagger, 1934, 24 cylinder H, 1,027 C.I.
Bristol Taurus, 1936, 14 cylinder 2 row, 1,550 C.I.
Peregrine showed up late, improved 1926 engine, V-12 1296 C.I.
A-S Deerhound 1935, 21 cylinder 3 row, 2,256 C.I.

Using more cylinders than the competition (or some of your own engines) is using and/or extra banks/crankthrows/crankshafts may not be the best way to go. It is accepting certain limits rather than trying to change limits (better bearings, better balancing, better finning/cooling).

Note that the Deerhound was using 21 cylinders to do what other people were doing with 14 cylinders.