Wars and ConflictsΒ permalink
A Fatal Flaw in the Lancaster Bomber?
This discussion has been closed.
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Message 1.Β
Posted by U3280211 (U3280211) on Wednesday, 27th May 2009
50% of American daylight bomber crews who had to bail-out over enemy territory in WW2 survived.
Night-raiding crews in RAF Stirlings and Halifaxes averaged a 25% survival rate .
Lancaster crews had the worst record of surviving a night attack, with only 15% parachuting down safely.
Iveson and Milton, βThe Lancaster, the Biographyβ (2009) argue that this statistically significant difference is due to the slightly narrower escape hatch in the Lancaster.
Might other factors be involved?
Any thoughts? -
Message 2
Posted by Ratbones (U13981844) on Thursday, 28th May 2009
There were two escape hatches in the Lancaster. The nose, and rear fuselage. The rear gunner simply had to rotate his turret 120 degrees and then just rolled out. The mid-upper gunner, wireless operator and navigator used the rear fuselage hatch. They wore chest-pack type parachutes which made things a little easier. The bomb-aimer was literally lying over the nose hatch, so usually baled out with relative ease. The flight-engineer lifted his folding seat, and stepped down into the nose over the glycol tank, and out.
The pilot however, wore a seat-type parachute which severely restricted movement. As soon as he relinquished control to escape, his time to exit was measured in seconds, thus very few Lancaster pilots survived. -
Message 3
Posted by farmersboy (U5592874) on Thursday, 28th May 2009
One factor you have to consider is the method of attack used and the damage inflicted.
Attacking a fleet of bombers in broad daylight. especially when making a head-on attack, only gave you a second or so of firing time, so bombers tended to get attacked again and again, the damage building to the point of destruction or bale-out. You'd expect a larger proportion of the crew to survive in such a scenario.
During a night raid the night-fighters would invariably concentrate on a single bomber at a time and take the time to get in close, coming from behind and/or underneath and attacking from as close as 70-100 yards. This would lead to a greater chance of destruction of the bomber, particularly if a loaded bomb bay was hit (although a lot of accounts show that the fire was generally aimed to fuel tanks and engines to give the crew some chance to bail out). -
Message 4
Posted by Spruggles (U13892773) on Thursday, 28th May 2009
First. The Stirling had to operate at a much lower level due to a design which restricted its wingspan there was therefore less time for the crew to make an emergency exit.
Secondly, our crews operated mainly at night which meant that disorientation of individuals must have taken its toll.
Thirdly, when you state that half the American crews survived could I ask how these figures were collated, Per aircraft or as a percentage of the whole casualty rate? The B17 and B24 had crews of up to ten as opposed to the Lancaster that had seven.
Lancaster crews with the exception of, as already mentioned, the pilot and rear gunner also had to remove form a storage area and clip on their parachutes before exit from the aircraft. I am not sure what the American procedure was.
Unfortunately most military aircraft by their very nature are death traps for some of the crew members. -
Message 5
Posted by U3280211 (U3280211) on Thursday, 28th May 2009
Ratbones (2)
The pilot however, wore a seat-type parachute which severely restricted movement. As soon as he relinquished control to escape, his time to exit was measured in seconds, thus very few Lancaster pilots survived.Β
That explains well why pilots were at greater risk, but there must have been higher mortality in other crew members too, to account for the stats.
Perhaps the powerful German night-fighters fitted with upward-fring 'Schrage Musik' cannon(Ju 88G especially) were sent into battle at the same altitude as the higher-flying Lancasters, perhaps because the Lancs greater speed was a better match for the 'infiltration from below' technique used by the fast twin night-fighters?
Reg Parker was one of a few Lanc pilots who survived (with four of his crew) a surprise Schrage Musik attack. His aircraft was "ripped in two" in a matter of seconds.
The USAAF Libs and Forts, with their ventral guns, could not be surprised in this way. -
Message 6
Posted by U3280211 (U3280211) on Thursday, 28th May 2009
Farmersboy.
I think you've found the primary reason:
During a night raid the night-fighters would invariably concentrate on a single bomber at a time and take the time to get in close, coming from behind and/or underneath Β
I've lost my copy but I think Len Deighton explored this factor in his book 'Bomber'? -
Message 7
Posted by U3280211 (U3280211) on Thursday, 28th May 2009
Spruggles (4)
you state that half the American crews survived could I ask how these figures were collatedΒ
The figures I gave in the OP come from page 221 of Iverson and Milton, (2009) Lancaster: The Biography.
They are not the authors' own collation but the work of Freeman Dyson, a bright young analyst who worked for Harris in 1944 and 45.
The figures are likely to be gross 'whole casualty rate', I would guess. The book does not say.
Dyson pointed out that skilled Lanc crews were being shot down at the same rate as novices by 1944, implying that the German surprise attack from below was dispatching all comers with equal ease.
Dyson did succeed in persuading Harris to widen the escape hatches by 4cm, but only in 1945, at war's end.
His analysis lead him to speculate that the weight of the Lanc without guns, armour and defensive ammunition would allow it to fly much faster, thus reducing the probability of night-figther attack, because the Germans were attacking an undefended 'blind-spot' anyhow.
I don't find that a convincing argument as it would not have taken long for the night fighters to realise that such converted Lancs were wholly undefended, from any angle. But later in the war armour and ammunition were indeed reduced as the NF threat receded. -
Message 8
Posted by Grumpyfred (U2228930) on Thursday, 28th May 2009
The Stirling was built to be able to fit through the doors of the existing hanger doors, thus had a shorter wing span,leading to a lower ceiling.
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Message 9
Posted by farmersboy (U5592874) on Friday, 29th May 2009
What defence can you offer when you don't know that your bomber has a nightfighter 70 yards directly underneath it about to fire a pair of 20mm cannon into your wing?
(Interesting to read how difficult it was to attack a bomber this way, flying your Me 110 straight and level under a Lanc while craning your head right back and looking above you, through a modified gunsight mounted above and behind your head) -
Message 10
Posted by Spruggles (U13892773) on Friday, 29th May 2009
A couple of points.
About the pilot. Yes he did have a seat parachute which restricted his movements but his seat was protected by armour plating so one should have canceled out the other, I would have thought.
About the Lancaster. It was an easy aircraft to fly and quite manoeuvrable for a bomber(Alex Henshaw the test pilot would regularly roll one for demonstration) but this counted for little at night. As far as defensive armament is concerned the original Mk 1 was fitted with a ventral gun position but it was recognised that it would have been virtually useless during operations( the range and hitting power of the standard .303 machine gun was easily outclassed by the cannon armament on German night-fighters, as was the front turret which was seldom manned, the radio operator was better used in the astrodome as an extra pair of eyes).
The rear turret was modified on certain squadrons where the perspex was removed for better visibility and the four .303 guns replaced with two of the American .5's for greater hitting power, however, the night-fighter had all the advantages, radar, homing devices and an excellent fighter control system. And of course the congestion of the bomber stream over the target area allowed easy identification of potential targets.
If for any reason the front escape hatches were u/s the crew then had to clamber over the infamous main spar to the rear hatches. NOT an easy task at the best of times; but when the aircraft was falling from the sky and the survivors pulling five or six Gs?.
Perhaps it needs to be remembered too that those wing tanks held 100 octane petrol not your high flash point Avgas. -
Message 11
Posted by U3280211 (U3280211) on Friday, 29th May 2009
Interesting to read how difficult it was to attack a bomber this wayΒ
And dangerous too. A successful attack would cause a shower of large and heavy debris which required a rapid turn and dive to avoid.
Even German NF aces were caught-out in this way. -
Message 12
Posted by TimTrack (U1730472) on Friday, 29th May 2009
"...About the pilot. Yes he did have a seat parachute which restricted his movements but his seat was protected by armour plating so one should have canceled out the other, I would have thought..."
Not really, if you think it through.
Armour protected the pilot from being killed or injured, so increased the chances of bringing the aircraft home. Returning aircraft often brought back dead crew members. The tail gunner was a famously dangerous job precisely because of this. His body was seen by the entire ground crew detachment.
But we are talking about downed aircraft, so returning pilots are not included in our stats here. So the value of the armour is not really included in the figures, even if it was highly effective.
If the armour failed to protect the pilots, the aircraft was shot down. That failure could be because the angle of attack by passed the armour, or the attack so deadly that the armour was destroyed anyway.
Considering that a dead pilot is one of the reasons that the aircraft is destroyed, you would actually expect a slight increase in fatalities compared to, say the navigator for downed aircraft.
Given the other reasons for the pilot not escaping (loss of control making mocvement impossible, and difficulty of reaching the escape hatch), then that all adds up to the pilot being in a difficult situation once the damage became un-sustainable. -
Message 13
Posted by Spruggles (U13892773) on Friday, 29th May 2009
TimTack,
What I meant was that by having armour plating the pilot had a better chance of surviving the initial attack, especially from the rear, unlike the poor old tail-end Charlie, so then the difficulty for the pilot in using the parachute was only relative. Sorry about the confusion.
Regards -
Message 14
Posted by Sambista (U4068266) on Saturday, 30th May 2009
I wonder if the differential between Lancaster and Stirling / Halifax crew survival rates might have something to do with the employment of the aircraft. Did Lancs tend to get the harder, ie better defended targets? IIRC Stirlings were largely moved to Coastal Command.
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Message 15
Posted by Mutatis_Mutandis (U8620894) on Saturday, 30th May 2009
Several factors influenced the different operational fates of the three heavy bombers, the Stirling, Halifax and Lancaster.
The chief problem with the Stirling was its limited ceiling. It is often claimed that this originated from a demand that the wing span should not exceed 100 ft. Legend has it that this was imposed because the RAF had hangars with doors 100 ft wide, but actually it had hangars with 120ft doors as well and was planning new ones with 150ft doors, and in any case you cannot easily get a 100ft aircraft through a 100ft door. More likely the limit was simply imposed to restrict the size, weight and cost of the aircraft. But even a Lancaster had a wing span of only 3 feet more than a Stirling: The real problem of the Stirling was not that its wing was too small, but that its structure was much heavier and less efficient: It had an empty weight about two tons, or 10%, heavier than a Halifax or Lancaster. This was partially the result of the RAF's short infatuation with the idea of catapult-launching heavy bombers, and partially of Short's background in the design of flying boats, which are subject to higher stresses.
The performance difference between Lancaster and Halifax had more subtle origins. The Lancaster was the more aerodynamically efficient of the two, especially in its engine mounts, which were long, well streamlined, and positioned slightly below the leading edge of the wing. It was also the more technically efficient, with an airframe design that was cheaper to build and allowing for more sub-contracting of assemblies.
Another factor was bomb bay design. The bomb load of the Stirling was partially in small cells in the wings, which could not take larger bombs than 500 lb; even its fuselage bomb bay could not carry a bomb larger than 2000 lb. The Halifax also had a restrictive bomb bay layout, and operationally it did rarely carry bombs over 2000 lb. The Lancaster had a vast, cavernous bomb bay with few obstructions, making it much more flexible.
Operationally, small differences in performance had a significant impact on loss rates, because the performance of German nightfighters was marginal for successful interceptions. It was found that removing the nose and dorsal turrets of a Halifax and replacing them with streamline fairings, significantly reduced the loss rate by making the aircraft faster. This was never done with the Lancaster because it was considered fast enough and the guns would be useful for possible daylight operations.
Finally, there is some irony in that in the second half of the war, many Halifaxes and Lancasters carried downward-looking radar. This H2S set was intended for navigation, and therefore its electronics were deliberately set up NOT to display any aircraft detected below the bomber. Only belatedly it was understood that it would be useful to put these air returns on a separate screen ('Fishpond'), giving warning of nightfighters approaching from below. -
Message 16
Posted by U3280211 (U3280211) on Saturday, 30th May 2009
MM (15)
Always a pleasure to read one of your informative posts.
This H2S set was intended for navigation, and therefore its electronics were deliberately set up NOT to display any aircraft detected below the bomber. Only belatedly it was understood that it would be useful to put these air returns on a separate screen ('Fishpond'), giving warning of nightfighters approaching from below.Β
Before your post I had no idea that H2S was at first actually set up to AVOID a/c returns.
Had the 'fishpond' addition been operational earlier it could have helped a charming gent I used to know called Len Hadland (DFC).
Len flew Lancasters with both 9 and 617 squadrons and on the Brunswick raid (night of 14th Feb, 1944, a year to the day before 'Dresden') Len was over the target, just about to release, when he was inadvertently 'bombed' by another Lancaster directly above him. 16 XIB incendiaries (the smaller magnesium ones) hit the aircraft; two hit engines, 5 penetrated the wings, four went through the tailplane and five penetrated the fuselage, one passing through the navigator's map and table and settling at his feet. Another wrecked the hydraulics.
Len brought his Lanc home on two engines with the bomb-bay doors stuck open. With the hydraulics severed in the 'attack' from above, he had to use the gas bottle to lower the undercarriage, the warning light showed 'gear-unlocked' but when they got permission for an emergency landing at Waddington, the gear held.
Given the concentration of the bomber stream over the target and each a/c responsible for its own navigation, my guess is that this was a serious and common problem which 'Fishpond' could have resolved?
All Len's squadron were carrying large 'cookies' that night, to be hit from above by one of those would have been a different matter. -
Message 17
Posted by Sambista (U4068266) on Saturday, 30th May 2009
Isn't it now accepted wisdom that Glen Miller was lost to bombs jettisoned from an aborted raid?
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Message 18
Posted by TimTrack (U1730472) on Monday, 1st June 2009
Mutatis : "...This was partially the result of the RAF's short infatuation with the idea of catapult-launching heavy bombers..."
Wow.
Did they ever actually launch a heavy bomber like that, or was it just an idea ? -
Message 19
Posted by Mutatis_Mutandis (U8620894) on Monday, 1st June 2009
Not as far as I know, although test rigs were built. This weird idea was around for only a short time, 1935-1936. The hope was that by using assisted take-off, heavy and medium bombers would be able to depart with higher weights, carrying more bombs and/or more fuel. Increases in range of 50% or more were predicted, and up to 200% in bomb load. The projected catapult would be able to launch a 60,000 lb aircraft at 110 mph, every three minutes.
As an alternative to a true catapult, a less complex system with the aircraft sitting on a powered truck running on rails was also proposed.
However, these advantages were claimed in comparison with relatively small grass airfields.
The scheme was quietly dropped when the RAF decided to build airfields with long hardened runways: This was cheaper than the construction of one or more large catapults at every airfield and offered more operational flexibility. The long runways were necessary anyway to allow the new bombers to land, and besides, thanks to variable-pitch propellers and flaps, the new bombers had better take-off performance than had been expected in 1935. -
Message 20
Posted by TimTrack (U1730472) on Tuesday, 2nd June 2009
Mutatis,
Thanks for the reply. The most sensible part of the plan seems to be the bit where it got quietly propped.
Still, I would have liked to have seen footage of a Stirling blasting off of an aircraft carrier. Step one : Find a stupid pilot.... -
Message 21
Posted by LongWeekend (U3023428) on Tuesday, 2nd June 2009
I think the proper comparison to make would be with the survival rate from the Fortresses shot down at night while operating in Bomber Command. The figures were presumably collated as part of the same OR study, but I don't know of where they might be found.
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Message 22
Posted by U3280211 (U3280211) on Wednesday, 3rd June 2009
LW (21)
I think the proper comparison to make would be with the survival rate from the Fortresses shot down at night while operating in Bomber Command.Β
That is an excellent idea as you would hopefully be comparing the risks and advantages of day vs night attack.
But what seems like a solution to the question might be more complicated, as I belive the RAF tended to fly the earlier B-17 C's (thin tail root, no rear turret, no Cheyenne hydraulics) which were inherently less safe than the better-defended 'F' and 'G' models.
If Freeman Dyson collected such loss data from the two cohorts, I've no idea where it might be held.
The other confounding variable is that the RAF used their B-17's by day, too. -
Message 23
Posted by LongWeekend (U3023428) on Thursday, 4th June 2009
U3280211
If what you are interested in, from IP, is the chance of successfully exiting a stricken aircraft, I don't think defensive armament is a factor (unless the internal layout of hatches and crew positions changed dramatically). Incidentally, the RAF also operated later models in the electronic warfare role.
Another possible area of comparison is the escape rate for B-29s in the night bombing role over Japan. This wouldn't be exact, of course, as the B-29s operated at low level (less time to get out) and had less chance of surviving once on the ground.
Cheers
LW -
Message 24
Posted by U3280211 (U3280211) on Thursday, 4th June 2009
LW
Thanks for getting back.
I don't think defensive armament is a factorΒ
Of course you are right that there is no necessary nor direct association between the defensive armament carried and the ease of leaving the aircraft after an attack or mishap.
But there could be an association if the nature of the defensive armament itself determines the form of an enemy's attack.
For instance, a slow-infiltration, 'Schrage Musik' attack on a daylight-raiding, ventrally-defended B-17 F would be an impossibility (I would have thought?) as the B-17's ventral guns, and those of the larger formation in the group, would drive off such an attack to a safe distance (say 3,000 feet?).
But the Lanc's absence of ventral protection (at least in the mass of production a/c) made such a night attack the preferred German tactic and we know that this was especially deadly.
I do not know, but would guess, that exploding cannon shells, fired from very short range, probably killed or disabled many crew at their stations, before they could even move towards the nearest escape hatch? -
Message 25
Posted by Mutatis_Mutandis (U8620894) on Thursday, 4th June 2009
For instance, a slow-infiltration, 'Schrage Musik' attack on a daylight-raiding, ventrally-defended B-17 F would be an impossibility (I would have thought?) as the B-17's ventral guns, and those of the larger formation in the group, would drive off such an attack to a safe distance (say 3,000 feet?).
But the Lanc's absence of ventral protection (at least in the mass of production a/c) made such a night attack the preferred German tactic and we know that this was especially deadly.Β
At night, a slow approach from slightly below and to the rear was standard, because this was the angle from which a bomber could most easily be seen and identified, silhouetted against the night sky. Most WWII radars had a minimal range greater than useful firing distances, and the final approach had to be done visually. A big advantage of 'Schraege Musik' was that this observation position also became the attack position. Night fighters armed only with forward-firing guns had to pull up into the field of view of the tail turret to open fire.
Generally one of two things happened: If the crew of the bomber saw the fighter, they would manoeuvre violently to shake off the attacker (as well as opening fire, but 'corkscrewing' had priority), and escape in the darkness. If they did not see the fighter, a few rounds into the fuel tanks in the wing root would be fatal.
In daylight the bomber could not manoeuvre to escape, but had to stay in formation. And the fighters had to get in quickly, fire from a close distance, and then get away again. Firing from a close distance was necessary because the B-17 and B-24 were very sturdy and getting enough hits to destroy one was difficult; there was an estimated expenditure of 1,000 rounds of 20-mm ammunition per bomber shot down. This lead to frontal attacks, which targeted pilots and engines directly, while the high closure rate made the job of the defensive gunners more difficult. In return, the defensive fire of the bombers was more spectacular than effective, with an average expenditure of about 40,000 rounds of .50 ammunition (a B-17 carried 12,000) for every German fighter downed.
So daylight combat tended to result in a much larger expenditure of ammunition, from both sides, with less conclusive results. At first glance, one would expect that with much more projectiles flying, the men were at greater risk. But on the other hand, a number of the bombers lost at day would have slowly accumulated damage, losing engines or gradually breaking up as they were hit again and again, but often in less critical areas. That would give the crew an opportunity to leave the aircraft. A successful interception at night would end with the bomber being set on fire by a few well-placed hits, leaving only seconds for the crew to get out. -
Message 26
Posted by abrazier (U3915690) on Friday, 5th June 2009
Anyone interested in gaming night fighter combat (hex and counter wargaming, not computer wargaming) might like to check out the following game which is currently in pre-publication development:
As a playtester I'm biased but this is a very challenging and fast playing simulation of night fighter actions throughout WWII. Check it out.
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