Why Didn't The RAF use Beaufighters Instead of Typhoons In The ETO

[EwenS]

According to RAF Squadrons by Jefford 43 squadron had some Beaufighter II July/August 1943 to go with their Hudson VI, based in Gibraltar with a detachment to Agadir. According to the RAF census as of end February 1943, no Beaufighter II located overseas, no overseas losses, as of end June 1944 none overseas, 2 losses either overseas or with the USAAF, while 86 had been sent to the Admiralty, along with 1 mark IF.

The Admiralty as of end January 1944 reports 14 Beaufighters in Britain, 29 overseas. (11 eastern theatre, 9 Western Mediterranean, 1 Eastern Mediterranean, 8 South Atlantic). The RAF Census for end December 1943 says 6 IIF in SEAAC, 42 to Admiralty, end January 1944 it was 6 in SEAAC, 45 to Admiralty.

??

43 was a single engined fighter squadron throughout WW2. In 1943 it was flying Spitfire MK.V/IX moving from Malta to Sicily in July /Aug 1943.

 

[EwenS]

This matches up exactly with a test of R2054 I have, and I don't think this would be a 'representative' Mk.I (though I'm far from any sort of Beaufighter expert).

R2054 was noted to have:

• early, prototype nacelles
• early, poor finish
• no flush riveting
• external escape door
• retractable tail wheel

I think a better bet would be R2060, which had did not have any of the above (and so had flush riveting, though no retractable tailwheel). This Mk.I was compared to the older one and did 323 mph at 14,250.

EDIT: Also, X7540 and X7542 were tested at 335 and 333 mph respectively, both just under 16,000 ft. These had:

• Hercules X
• improved air intakes
• undercarriage door close mod.

All this said -- the Typhoon had 55+ to 75+ mph on the Beaufighter under 10,000 (depending on the number of Typhoon refinements).

For what it's worth, in British testing there was almost nothing to choose speed-wise between a Boston III/IIIa and a Beaufighter (Herc X/Herc VI).

From John F Hamlin's "Bristol Beaufighter, The Full Story" published by Air Britain, which has aircraft histories for all aircraft built.

R2052 - first prototype with Hercules I. FF 17/7/39. A&AEE 2/4/40 for handling trials, including diving at up to 400mph IAAS at max loaded weigh; DRGD \boscombe Down 9/12/40 damaged beyond repair 23/2/41.

R2054 - Mk.I prototype with Hercules III. To A&AEE 4/6/40 for radio trials. 4 MU 20/9/40
R2055 - Mk.I prototype with Hercules II. To A&AEE 4/6/40 for gunnery trials
R2060 - TOC 20/7/40; A&AEE 2/12/40 for speed measurement and gunnery trials

X7540 - TOC A&AEE 26/2/41 for performance trial
X7542 - TOC 32 MU 6/3/41; Bristol 26/3/41 to fit dihedral tailplane; A&AEE 5/10/41 for determination of max still air range.

 

[Reluctant Poster]

Also, for the Vulture it seems that the engine produced vibrations that tended to make the Manchester tail fall off. Perhaps that was the inspiration for the movie "No Highway In The Sky

That sounds like urban legend to me . Any references?

 

[Thumpalumpacus]

My understanding was that the Vulture was prone to overheating and fire.

 

[buffnut453]

That sounds like urban legend to me . Any references?

I've seen reference to excessive tail flutter with the Manchester but not issues of the tail falling off, and certainly not due to engine vibrations.

 

[don4331]

My understanding was that the Vulture was prone to overheating and fire.

The Vulture has 5 issues:

1. If upper and lower crankcase halves aren't kept in exact alignment, the main bearings aren't aligned = crankshaft starved for oil = seized. Keeping aligned in production environment is nearly impossible. Solution larger dowels ("cheeses") between crankcase halves and precise tightening sequence.​

2. Vulture used 2 cooling pumps (one for each 1/2 of the engine). Because of the cooling piping design, one pump or other would tend to cavitate and stop pumping. No cooling medium = engine overheats and seize. Solution: Balance pipe between the pumps and there were no longer cavitation issues.​

3. Connecting rod bolts have 2 issues: When connecting rod fails, it tends to punch hole in side of block. Oil pours out, flowing down onto red hot exhaust.​

a. Bolts have poor heat treating and don't meet strength requirement. Solution: More stringent heat treatment​

b. Connecting rod uses 2 different lengths of bolts. The longer bolt stretches more before it provides the same clamping force, so you need 2 different tightening torques. If you tighten the short bolt too much, it fails, if you tighten the long bolt too much the cap isn't properly held in place. Solution: Go/No Go gauge to check the bolt stretch. If short bolt is stretched too much you can't push the gauge in (No Go) and you have to unbolt, throw the ruin bolt/nut into recycling and install new bolt, nut and torque correctly.​

4. Rolls Royce tries battery/coil/points/condenser instead of magnetos. Dead battery/failed coil/points/condenser = no spark. Solution replace with magnetos.​

But by the time RR has diagnosed the issues and resolved them, the Vulture has a bad reputation. Last of the Vultures were getting 150 hours before overhaul; which would be a good as another other UK engine of the time period.

5. The Vulture I was designed for 1,750 hp on 87 octane fuel. 100 octane fuel is now available in quantity. Vulture needs be redesigned for 2,500 hp:​

a. Larger carburetor​

b. Larger supercharger; stronger supercharger gears (and we haven't got into 2 stage)​

c. Stronger pistons​

d. Stronger connecting rods​

e. Stronger crankshaft​

f. Stronger crankcase​

g. Stronger reduction gear​

h. Larger cooling pumps​

and I've probably missed something.​

​

At the same time, RR has the same issue with the:

Peregrine I - they just bin this...if you want 1,200hp get a Merlin I, if it doesn't fit in your airplane - that's your issue, not RR problem.​

Merlin I - which they are redesigning as Merlin XX to support 1,500+ hp.​

Griffon I - they bin the initial design and take what they've learned to create Griffon IV, 1,750+ hp.​

Vulture...RR bins it; at the time, there is no airframe requiring a 2,500 hp engine.​

​

Back to the Manchester.

Not only is RR having issues with their engine, Avro is having issues with their airframe:​

1. It doesn't want to fly on single engine (one a day in Tampa Bay comes to mind with B-26).​

Aside: For a plane, the designer needs to compromise; he needs enough fin/rudder area for pilot be be able to control the airplane just after take off. But he wants to keep it as small as possible to minimize drag. For a twin, he has 3 choices.​

A. Single fin/rudder: Advantage: Out of propwash, so minimizes drag during cruise. Disadvantage: Out of propwash; issue if an engine fails... So, single fin/rudder needs to be larger, which has issue with fuselage twisting (less of an issue with tail dragger as fuselage needs to be strong for other reasons)​

B. Twin fin/rudder: Advantage: In propwash, if an engine fails, there will still be rapidly moving air across at least one fin/rudder. Disadvantage: In propwash all the time; adds drag during cruise.​

C. Triple fin/rudder - central fin and small twin fin/rudders. Avro also made the tail plane narrow - which sounds like great idea - twin fin/rudders are mostly out of the propwash reducing drag during cruise. The problem: the Manchester needs to yaw a little before the fin/rudder gets into propwash, increasing drag... And the last thing you need when the critical engine fails when you are just clearing the engine of the runway at max take off weight is a little drag.​

Solution increase tail plane from 22' to 33' increase size of fin/rudders​

2. The plane is overweight...Solution addition wing area (wingspan increased from 90 to 95' (more drag/slower, but safer; again sounds like B-26)​

 

[HP52]

I found it interesting to compare the much touted Douglas Skyraider with the Bristol Beaufighter and superficially they are very similar bar the Beaufighter needing more hard points. There are differences in size, empty weight etc. but they overall appear to be in much the same class and a pair of post war 2,000bhp Hercules engines, as used in civil aeroplanes, gives the Beaufighter 4,000bhp to lift off a higher armament weight had it more hard points. Whilst designed as a heavy fighter the Beaufighter was principally used as a ground attack aeroplane too.

So, if the Beaufighter was a large vulnerable target to AA fire, the Skyraider must be too. The Typhoon was used for the role not because it was smaller, although it was, but essentially because it was there. Production was geared up so they were going to be made anyway and could do the ground attack task very adequately. Less of a Top Trumps comparison of performance than a logistical choice looked at from a high level.

Don't forget the Beau Nav had a soft-hard hat (spring steel strips in a leather helmet). One 455 chap survived a prop strike collision, penetrating the Nav's bubble.

 

[HP52]

The Vulture has 5 issues:

1. If upper and lower crankcase halves aren't kept in exact alignment, the main bearings aren't aligned = crankshaft starved for oil = seized. Keeping aligned in production environment is nearly impossible. Solution larger dowels ("cheeses") between crankcase halves and precise tightening sequence.
2. Vulture used 2 cooling pumps (one for each 1/2 of the engine). Because of the cooling piping design, one pump or other would tend to cavitate and stop pumping. No cooling medium = engine overheats and seize. Solution: Balance pipe between the pumps and there were no longer cavitation issues.
3. Connecting rod bolts have 2 issues: When connecting rod fails, it tends to punch hole in side of block. Oil pours out, flowing down onto red hot exhaust.​

a. Bolts have poor heat treating and don't meet strength requirement. Solution: More stringent heat treatment
b. Connecting rod uses 2 different lengths of bolts. The longer bolt stretches more before it provides the same clamping force, so you need 2 different tightening torques. If you tighten the short bolt too much, it fails, if you tighten the long bolt too much the cap isn't properly held in place. Solution: Go/No Go gauge to check the bolt stretch. If short bolt is stretched too much you can't push the gauge in (No Go) and you have to unbolt, throw the ruin bolt/nut into recycling and install new bolt, nut and torque correctly.​

4. Rolls Royce tries battery/coil/points/condenser instead of magnetos. Dead battery/failed coil/points/condenser = no spark. Solution replace with magnetos.​

But by the time RR has diagnosed the issues and resolved them, the Vulture has a bad reputation. Last of the Vultures were getting 150 hours before overhaul; which would be a good as another other UK engine of the time period.

5. The Vulture I was designed for 1,750 hp on 87 octane fuel. 100 octane fuel is now available in quantity. Vulture needs be redesigned for 2,500 hp:​

a. Larger carburetor
b. Larger supercharger; stronger supercharger gears (and we haven't got into 2 stage)
c. Stronger pistons
d. Stronger connecting rods
e. Stronger crankshaft
f. Stronger crankcase
g. Stronger reduction gear
h. Larger cooling pumps
and I've probably missed something.
​

At the same time, RR has the same issue with the:

Peregrine I - they just bin this...if you want 1,200hp get a Merlin I, if it doesn't fit in your airplane - that's your issue, not RR problem.
Merlin I - which they are redesigning as Merlin XX to support 1,500+ hp.
Griffon I - they bin the initial design and take what they've learned to create Griffon IV, 1,750+ hp.
Vulture...RR bins it; at the time, there is no airframe requiring a 2,500 hp engine.
​

Back to the Manchester.

Not only is RR having issues with their engine, Avro is having issues with their airframe:
1. It doesn't want to fly on single engine (one a day in Tampa Bay comes to mind with B-26).
Aside: For a plane, the designer needs to compromise; he needs enough fin/rudder area for pilot be be able to control the airplane just after take off. But he wants to keep it as small as possible to minimize drag. For a twin, he has 3 choices.​

A. Single fin/rudder: Advantage: Out of propwash, so minimizes drag during cruise. Disadvantage: Out of propwash; issue if an engine fails... So, single fin/rudder needs to be larger, which has issue with fuselage twisting (less of an issue with tail dragger as fuselage needs to be strong for other reasons)
B. Twin fin/rudder: Advantage: In propwash, if an engine fails, there will still be rapidly moving air across at least one fin/rudder. Disadvantage: In propwash all the time; adds drag during cruise.
C. Triple fin/rudder - central fin and small twin fin/rudders. Avro also made the tail plane narrow - which sounds like great idea - twin fin/rudders are mostly out of the propwash reducing drag during cruise. The problem: the Manchester needs to yaw a little before the fin/rudder gets into propwash, increasing drag... And the last thing you need when the critical engine fails when you are just clearing the engine of the runway at max take off weight is a little drag.​

Solution increase tail plane from 22' to 33' increase size of fin/rudders
2. The plane is overweight...Solution addition wing area (wingspan increased from 90 to 95' (more drag/slower, but safer; again sounds like B-26)​

Did the articulated conrods on the Vulture in anyway contribute to its reliability problems?
HP52

 

[Simon Thomas]

The Manchester also had numerous prop failures at the same time the Vulture was having issues.
The book "Avro Manchester: The Legend Behind the Lancaster" by Robert Kirby goes into some detail about the issues, and the steps made to correct them.
My takeaway is that the Vulture was as good as the rest of the engines in service when the decision was made to terminate it.

 

[MIflyer]

1. It doesn't want to fly on single engine

The Manchester at the time was the only British built twin with featherable propellers. This led to it being used to simulate enemy gliders penetrating defenses.