Bomber Comparison

[Greyman]

Plugging away on a little project dealing with a comparison of the Lancaster and Fortress. I imagine the Lancaster Mk.I (Merlin XX or perhaps 22) and the B-17F would be a reasonable comparison.

I realize this kind of discussion has been gone over several times in the past but I'm looking for a slightly different angle.

Building on some documents from WWII Aircraft Performance as a base (RAF data sheets, USAAF memo), I'm wondering if anyone has come across any other opinions/comparisons/studies from pilots, aircrew or brass.

 

[Glider]

One carried bombs the other guns

 

[Greyman]

Numbers I have for the Lancaster:

2 x nose guns - 46.5 lb
- and 2000 rds - 132.5 lb
2 x upper guns - 46.5 lb
- and 2000 rds - 132.5 lb
2 x under guns - 46.5 lb
- and 2000 rds - 66.5 lb
4 x rear guns - 92.0 lb
- and 2400 rds on tracks - 159.0 lb
- and 7600 rds in boxes - 503.5 lb

FN5 - 237.5 lb
FN50 - 340 lb
FN64 - 158 lb
FN20 - 325 lb

Total - 2,286 lb w/ mid-under
Total - 2,015 lb w/o mid-under

I suppose 800 pounds should also be added for the four gunners, though the front turret wasn't a full-time position. I'm not sure how the mid-under was typically manned on operations.

Anyone have figures for the B-17F?

 

[Shortround6]

Plugging away on a little project dealing with a comparison of the Lancaster and Fortress. I imagine the Lancaster Mk.I (Merlin XX or perhaps 22) and the B-17F would be a reasonable comparison.

Trouble is that the Boeing 299 first flew July 28th 1935 and the Avro Manchester first flew almost exactly 4 years later. July 25th 1939. Both planes were extensively modified to become the B-17E and Lancaster MK I but both planes did carry quite a bit of their "legacy" with them.

For the B-17 it was a bomb bay that was initially supposed to hold eight 600lb bombs, Not bad for four engines of 875hp take-off each and 750hp max continuous at 7000ft. The YP-17s got better but without changing the wing spar spacing or moving the wing from the bottom of the fuselage to the top or some other major surgery the B-17 was never going to carry the internal load of the Lancaster and it had very little to do with the guns. The Boeing 299 carried a whopping five .30 cal guns in single manual mounts. The .50 cal gun didn't make it's appearance on new aircraft until the B-17C (although some older planes were refitted) in 1940. Still five single gun positions.

It was a lot easier to add gun positions/turrets than redo the basic structure of the aircraft. Over 130 B-17s had been built by the time you get to the "E" model so retooling was not looked at with favor.

 

[Shortround6]

Anyone have figures for the B-17F?

Nine .50 cal guns at 75lbs each?= 675lbs
3500 rounds of .50cal at 30lbs/100= 1050lbs.

I have no weight for turrets and the above guns and ammo are from the flight manual and included in the basic weight.
Extra guns and ammo carried by crews on operations could vary.

 

[dogsbody]

Except in a few cases ( Mk.II and a few others ) Lancasters didn't carry underside guns.


Chris

 

[Greyman]

My best guesses at B-17 weights based on British figures on a Boston Mk.IV 'Weights & Loading' paper.

Nose Gun
- 1 x gun - 82.6 lb
- ??? rounds - ??? lb (+ ammo box, 9.4 lb)
Sperry Upper Turret - ??? lb
- 2 x guns - 130 lb
- 900 rounds - 270 lb (+ 2 x ammo boxes, 21.6 lb)
Sperry Ball Turret - ??? lb
- 2 x guns - 130 lb
- ??? rounds - ??? lb (+ 2 x ammo boxes, 21.6 lb)
Beam Guns
- 2 x guns - 165.2 lb
- 200 rounds - 60 lb (+ 2 x ammo boxes, 18.8 lb)
Tail Guns
- 2 x guns - 130 lb
- 1300 rounds - 390 lb (+ 2 x ammo boxes, 21.6 lb)

Spare/unaccounted for ammunition - 1,100 rounds - 330 lb
(based on 3,500-rounds figure in manual)

(running) Total - 1,780.8 lb

 

[pbehn]

The B 17 had a co pilot the Lancaster didnt. I dont know how much a pilot, parachute, seat, oxygen, dual controls etc weigh but it must be quite a bit.

 

[stona]

I'm not sure how the mid-under was typically manned on operations.

The mid-upper turret was permanently manned by an air gunner, one of the standard seven man crew for a main force Lancaster.

(1.Pilot, 2.Flight Engineer, 3.Navigator, 4.Bomb Aimer/Front Gunner, 5.Wireless Operator, 6.Mid-Upper Gunner, 7.Rear Gunner).

Some PFF or 100 Group (RCM) aircraft carried extra 'Special Equipment Operators' and all new pilots had to fly at least one operation as a 'second dickey' with an experienced crew before taking their own crew on operations.

Bomb aimers usually had fairly rudimentary training in air gunnery, so it was just as well the front turret guns were very rarely used. Most crews never fired any of their guns and I'm struggling to think of any account in which the front turret was used on a normal night time mission.

Flight engineers often had a basic ability to fly the aircraft, having been bumped off pilot training courses at some stage. Some basic flight training for engineers was introduced when the second pilot was removed from British bombers and smart pilots gave their engineers a little unofficial hands on experience. More than one aircraft and crew were saved by the ability of their flight engineer when their pilot was killed or incapacitated.

Cheers

Steve

 

[Robert Porter]

I wondered about the no copilot idea, according to casualty figures on B-17's and B-24's, the only aircraft I have figures for, a LOT of either Pilots or CoPilots were injured sufficiently during a raid to be rendered unable to fly. Flak, enemy canon fire etc. Having a spare pilot just seems to be good sense. I assume in the Lancaster's case if the pilot were rendered unable to fly the crew just bailed out if they could? Of course given the proximity of the two pilots in the American bombers anything capable of injuring one probably injured both so I suppose in that context the result would be the same.

 

[buffnut453]

As Steve mentioned previously, many crews would cross-train in different positions. The Flight Engineer or Navigator might be trained on some basic piloting skills. Wireless/Air Gunners (WAGs) were not uncommon to remove single points of (human) failure within the crew - losing your radio operator is a bad thing if trying to find home in bad weather, while losing a gunner essentially takes an entire turret out of action in an RAF bomber, which greatly increases the risk that the aircraft will be shot down.

 

[Shortround6]

I think there is a difference, however the difference is not as large as it might first appear. As several people have noted, most large British bombers did have someone who could take over from the pilot IF there was time to to pull the pilot from his seat and the new crewman take-over. The substitute might not be able to land the plane but could probably get it back to friendly territory where the crew could at least bail out.
Of course this assumes, in both cases, that whatever damage killed the pilot didn't also damage any of the flight controls.
American bombers were also designed to fly long distances, even the B-25 and B-26 were designed to fly 2000 miles at around 200mph which makes having a relief pilot a good idea?
Boeing 299 was rated at "Range 2040 miles with 2573 pounds of bombs. Maximum range 3101 miles" and a Cruising speed of 204mph. the 3101 mile figure may be ferry range and an even slower cruise speed.
By the time you get to the B-17B the plane could fly 2500 miles carrying 2573lbs of bombs at 176mph at 10,000ft. Or over 14 hours of flight.
Having "Pacific" versions with two pilots and "European" versions with one pilot probably didn't make much sense for a training viewpoint. Different duties for the Flight engineer, different cockpit checklists and so on.

 

[stona]

The cross over between roles in Bomber Command was very limited. Officially only flight engineers had any flying training. The others were not officially trained at all in each others roles, apart from a brief air gunnery course for the bomb aimer. Of all, the air gunners would be least likely to have any other skill.

Here is not the place for a discussion on the crewing of British bombers, but two factors in its development stand out.
During the mid 1930s the Air Ministry felt that the pilot should also be the principle navigator. It soon became apparent that one pilot/navigator could not fulfill all the tasks demanded of him. This led to the addition of a second pilot/navigator. In 1937 it was decided that all medium and heavy bombers should have a second pilot.
Some machines, such as the Hampden, had no place for a second pilot. To ease the pilots work load it was decided to train an observer to navigate, though he would still be trained in bomb aiming and gunnery. By 1938 it was obvious that the navigation was a task in itself and a separate role as navigator was recognised.
There was some confused thinking. As the second pilot/navigator was added to aircraft which could carry him, the separate role of navigator, which rendered the second pilot superfluous, was emerging. Nonetheless, the standard for RAF medium and heavy bombers from 1937 until 1941 was that these aircraft be supplied with two pilots. Look at the cockpit of a Stirling, Wellington, or Manchester of the period and they retain controls for two pilots, I think the Halifax was the first 'heavy' to have single controls, but I'm not sure about the earliest versions, B.12/36 certainly specified two pilots 'one to act as navigator'.
The two pilots were only reduced to one in late 1941 as Bomber Command started to expand. By reducing the requirement to one pilot per aircraft the ratio of available pilots to aircraft was doubled at the stroke of a pen. It was also recognised that accurate navigation was a full time job, the old overland "by guess and by God" method was not going to get anyone to a target in the Ruhr. On 17th May 1939 the Air Officer Commanding 3 Group reported that Dead Reckoning navigation, by day, over cloud, could be expected to bring an aircraft only within about 50 miles of a target. The navigator's training course became as long as the pilot's.
Cheers
Steve

 

[Greyman]

Looking at the performance of the Fortress, does anyone know if the following is a good representation of a 'standard' USAAF B-17F in service?

• Cyclone GR1820-65 engines
• Stromberg pressure injection PD12 H2 carbs
• GE B2 turbo-superchargers
• Hamilton Standard Hydromatic props (11' 6")

 

[Greyman]

Anyone know what type/brand of self sealing material the Fortress 'F' used?

 

[Greyman]

Anyone know what the story is with the change in Fortress mid-upper turrets? I notice a change partway through the 'F's ...

 

[fubar57]

So far I've only seen it on the G-1....

​

.....but then I just started looking

 

[Milosh]

An old RCAF WAG was telling stories of his service time. He was based at Summerside PEI with 1 GRS. They would fly out over the Gulf of St Lawrence on boring training missions for navigators. The WAG or RO would replace the pilot at the controls. The trainee navs liked when this was done as the WAG/RO concentrated on flying the course required while the pilot was a bit lax in doing so. Anyways, it got to the point where a WAG/RO would pilot the a/c (Anson) even on take offs. This came to and end when some birds were hit and the a/c crashed (no fatalities). The CO was rather upset about this practice.

When asked if this happened at other bases he didn't know but stated it probably did.

 

[Robert Porter]

The turret was changed from Sperry to Bendix, interesting story here about the change: B17 Later Models

 

[Old Wizard]