fastmongrel
1st Sergeant
Must be the crummy allied aerodynamics
They should have used a napkin to do the numbers the B29 could easily have cruised at 450 mph at an altitude of 55,000 feet carrying a Grand Slam bomb under each wing.
Why did Britain give up on the Avro Manchester bomber? (1 Viewer)
- Thread starter davebender
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They should have used a napkin to do the numbers the B29 could easily have cruised at 450 mph at an altitude of 55,000 feet carrying a Grand Slam bomb under each wing.
davparlr
Senior Master Sergeant
Several web sites and my "German Combat Planes" by Ray Wagner and Heinz Nowarra shows 303 mph for the A-4. And it passes the smell test.
parsifal
Colonel
My sources give the top speed of the A-5/r4 subtype @ 41000 lbs as 295 MPH @ 26000 feet.
The He 177 had a good turn of speed compared to the lancaster, but considering it (the A-5) was not introduced until 2years after the Lancaster mk I , that should not be surprising
The He 177 had a good turn of speed compared to the lancaster, but considering it (the A-5) was not introduced until 2years after the Lancaster mk I , that should not be surprising
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- #24
davebender
1st Lieutenant
That entirely misses the point of why I mentioned the He-177.
Is a bomber with two large engines inherently faster then a bomber with 4 small engines?
parsifal
Colonel
well, in the case of the he177, i would say yes, but not by much
Shortround6
Major General
If we assume that the two bombers will have equal bomb loads, carried over equal distances with an equal defensive armament and crewed by the same number of men the answer is yes, but as has been stated, not by a great amount.
The British were very interested in big twins but they didn't work out in practice, see the Vickers Warwick in addition to the Manchester and the Halifax was originally sketched as a big twin.
There were usually two differences between theory and reality. One was the engine out situation, a big twin losing one engine was like a 4 engine plane loosing two engines on the same side. Climb rate on one engine was sometimes in the negative numbers. Second was that at any given time most countries did not have a "big" engine that was twice the power of a common smaller engine. Vulture was essentially two up rated Kestrels not two Merlins, Bristol Centaurus was essentially two 9 cylinder Perseus engines not a double Hercules. even the US R-3350 Double Cyclone wasn't really two R-1820 Cyclones.
On a really clean airframe the difference between 4 small nacelles and two large nacelles may make a noticeable difference, once you add a number of drag producing gun positions/turrets, astro domes, antennas and such the differences in engine nacelle drag, while measurable, becomes a much smaller piece of the pie.
How long did it take for the He177 to become a somewhat usable a/c? Note the design started in 1936.
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- #28
davebender
1st Lieutenant
One of the primary advantages of a fast cruise speed is you don't need so many defensive gun positions and crew to operate them. Speed itself makes the bomber more difficult to intercept with fighters and to hit with AA fire. This allows a greater portion of the total aircraft payload (loaded weight minus empty weight) to be used for fuel and bomb load.
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- #29
davebender
1st Lieutenant
17 April 1936. Bomber A specification issued by RLM.
.....Top speed of 335 mph
.....Operational radius of 1,000 miles with a 2,000kg payload.
.....Operational radius of 1,800 miles with a 1,000kg payload.
.....Expected to be operational by 1940.
The last item proved wildly optimistic.
February 1943. He-177A5 enters service.
This was the main production version with most of the bugs fixed.
Back to the Avro Manchester....
November 1936. 7 months after the German Bomber A specification.
RAF issued Specification P13/36 which initiated development of the Manchester bomber.
So....
If the Manchester bomber develops at the same pace as the German He-177 then it should be fully operational and in mass production before the end of 1943.
However the two aircraft programs have different technical bottlenecks. He-177 engines per se worked just fine. Heinkel had to fix the He-177 engine cowlings. I think that took a lot of experimentation to get them right. The Manchester will probably need a different engine, which will likely be the 24 cylinder Sabre.
.....Top speed of 335 mph
.....Operational radius of 1,000 miles with a 2,000kg payload.
.....Operational radius of 1,800 miles with a 1,000kg payload.
.....Expected to be operational by 1940.
The last item proved wildly optimistic.
February 1943. He-177A5 enters service.
This was the main production version with most of the bugs fixed.
Back to the Avro Manchester....
November 1936. 7 months after the German Bomber A specification.
RAF issued Specification P13/36 which initiated development of the Manchester bomber.
So....
If the Manchester bomber develops at the same pace as the German He-177 then it should be fully operational and in mass production before the end of 1943.
However the two aircraft programs have different technical bottlenecks. He-177 engines per se worked just fine. Heinkel had to fix the He-177 engine cowlings. I think that took a lot of experimentation to get them right. The Manchester will probably need a different engine, which will likely be the 24 cylinder Sabre.
If one wants a to re-engine the Manchester ASAP, R-2800s would've been the right choice. Of course, only humble numbers would've been available in 1942. Turboed 2800s ring favorably too (flying comfortably at 25K at decent speed, descend to 15K for a bomb run, then climbing above 25K heading home), but again low numbers kick in prior 1943.
As a night bomber that relies at avoidance, rather than to gun down opposing fighters, some reduction in defensive armament would've reduced drag weight, adding to survivability. Plus, the higher cruising speed service ceiling help avoid most of the Flak.
As a night bomber that relies at avoidance, rather than to gun down opposing fighters, some reduction in defensive armament would've reduced drag weight, adding to survivability. Plus, the higher cruising speed service ceiling help avoid most of the Flak.
The He177 got a different engine, DB606 > DB610. There was more than just the cowlings as oil tended to collect and cause fires.
3 March 1942 was the date of the first Lancaster mission, a year ahead of the A-5. This means the British are dropping masses of bombs on Germany for a year. A viable weapon in use while waiting for a Manchester powered by the questionable Sabre engines to mature.
3 March 1942 was the date of the first Lancaster mission, a year ahead of the A-5. This means the British are dropping masses of bombs on Germany for a year. A viable weapon in use while waiting for a Manchester powered by the questionable Sabre engines to mature.
parsifal
Colonel
Only true if the aircraft has a significant speed advantage. A good example of the 'fast bomber' concept that just failed was the blenheim. It sacrificed armament for speed, and in its time WAS a fast bomber. but by the time it got into a war, it just wasnt fast enough. most german bombers also traded armament for speed, and in the context of 1936 this kind of worked. but by 1939 these 'un-interceptable' bombers were easily caught and hopelessly outgunned. they were immediately vulnerable, which the germans tried to compensate for by adding extra guns and armour. What had been high performance aircraft in 1937, became lumbering targets in 1942.
In the case of the ju-88 it was somewhat better because it was a manouverable aircraft, and because it was better in terms of its speed, but still, as a conventional day bomber it remained vulnerable. The he 177 was even faster than a ju88, and in fact proved that it could bomb england 9allbeit rather innaccurately) by adopting glide bombing techniques. If it did that, it could reach speeds of 400MPH, and thereby stay alive.
But the best bombers of this philosophy were unadulterated by any defensive armament. i speak of course of the mosquito and later the AR 234. moreover these aircraft remained devoid of defensive armament throughout their careers as bombers, and yet suffered perhaps the lowest attrition rates of any bomber during the war.
with regard to the he 177, it simply did not have the level speed capability to be put in that category. it remained vulnerable, simply because was too slow to be able to claim invulnerability advantage
Shortround6
Major General
If the flak could reach B-24s and B-17s in daylight then flying at the same altitudes by night isn't going to change things much. The standard 8.8cm Flak 36 had an effective ceiling of 8,000 meters (max ceiling of 9900 meters) while the 10.5cm Flak 38 had an effective ceiling of 9450 meters. If you are flying over 4000 meters you are out of the range of any of the 37-40mm stuff.
- Thread starter
- #34
davebender
1st Lieutenant
An interesting possibility.
The 24 cylinder British Sabre engine won't be debugged and available in quantity prior to 1944. 2,000+ hp R2800 radial engines might be available in quantity during 1943.
The 24 cylinder British Sabre engine won't be debugged and available in quantity prior to 1944. 2,000+ hp R2800 radial engines might be available in quantity during 1943.
- Thread starter
- #35
davebender
1st Lieutenant
Higher speed shortens the time a bomber is exposed to flak. But you cannot completely avoid flak if you bomb from an altitude which allows you to hit the target. Just one of the occupational hazzards of war.
Shortround6
Major General
The fast bomber only works with a certain payload/range combination. The Original specification/requirement for the Manchester called for 3000lbs to be carried for 3000 miles or 8000lbs to be carried for shorter distances. Please note that this is three times farther than an early B-26 could carry 3000lbs. The Planes designed to this specification (but not built) carried in the neighborhood of 1600-1700imp gallons of fuel. To meet the field requirements (take-off and landing distances or landing speeds) required a certain wing loading and so a certain sized wing. once you are faced with these requirements/limitations the speed has dropped to a point where speed alone might not be enough protection and the weight of the guns and crew aren't that big a percentage.
pbfoot
1st Lieutenant
Britain gave up on the manchester because it was crap
1) the heated flying suits had individual outlets for each piece of clothing in other words each glove had its own receptacle
2) to rectify this they pumped hat air from oil cooler into aircraft but with only one outlet at the radio operators position it was so hot the RO couldn't remain in position so it was blocked off by crews
3)the feathering solinoid for the prop was faulty and frequently changed the pitch of the prop witthout prompts
4)the high pressure hydraulic system was junk with no "olives" on the joints which would frequently blow , paper washers on the engineers panel would also fail
5) Getting bombays open " The designers had thought of this one. Holes bored in the lower side of the bombay actuatorswere were filled with plugs connected to a steel cable running to the front of the bombbayinside the nose section. pulling this wirewthdrew the plugs from the hydraulic jacksand the oil drained by gravity. The bombays sagged enoug for the slipstream to catch them and whip them fully open. We would drop our bombs but would have to fly remainder of mission with bomb doors open
6) although designed to carry a 4000lb bomb the bomb had yet to be designed and the bomb was to big so they cut open the bombay and the bomb doors were modified with bungee cords so the doors would close
7) This pilot reported that one would get exhausted after flying 3 circuits
1) the heated flying suits had individual outlets for each piece of clothing in other words each glove had its own receptacle
2) to rectify this they pumped hat air from oil cooler into aircraft but with only one outlet at the radio operators position it was so hot the RO couldn't remain in position so it was blocked off by crews
3)the feathering solinoid for the prop was faulty and frequently changed the pitch of the prop witthout prompts
4)the high pressure hydraulic system was junk with no "olives" on the joints which would frequently blow , paper washers on the engineers panel would also fail
5) Getting bombays open " The designers had thought of this one. Holes bored in the lower side of the bombay actuatorswere were filled with plugs connected to a steel cable running to the front of the bombbayinside the nose section. pulling this wirewthdrew the plugs from the hydraulic jacksand the oil drained by gravity. The bombays sagged enoug for the slipstream to catch them and whip them fully open. We would drop our bombs but would have to fly remainder of mission with bomb doors open
6) although designed to carry a 4000lb bomb the bomb had yet to be designed and the bomb was to big so they cut open the bombay and the bomb doors were modified with bungee cords so the doors would close
7) This pilot reported that one would get exhausted after flying 3 circuits
The weight of the guns and extra crew to man them may not be much, but it seems you're forgetting about the turrets most of those guns fired from.
Each turret weighed in the region 1000+ lbs, plus the extra power the engines had to have to power the hydraulic pumps, or extra generating power for the electric turrets. Plus extra oxygen cylinders, lines.
You could easily add 1000lb per defensive gun by the time you add all the extra systems needed for that gun. Turret and power system, gun, ammo, and feed systems for the gun, crewman and life support systems.
Each turret weighed in the region 1000+ lbs, plus the extra power the engines had to have to power the hydraulic pumps, or extra generating power for the electric turrets. Plus extra oxygen cylinders, lines.
You could easily add 1000lb per defensive gun by the time you add all the extra systems needed for that gun. Turret and power system, gun, ammo, and feed systems for the gun, crewman and life support systems.
Shortround6
Major General
100lb per gun? I don't think so.
Lets try a reality check. Bolton Paul Defiant fighter vrs Hurricane. about a 2000lb difference in flying weights. Granted the Hurricane had eight forward firing guns but it was carrying about 2670 rounds of ammo compared to the 2400 rounds in the Defiant. Defiant also carried about 25 imp gallons more fuel.
Perhaps 500lbs per gun if mounted in a turret and manned by a crew member who had no other duties? Like radio operator, navigator or Flight engineer or?
And this is for the turret mounted guns. Non- turret mounted guns weigh how much? But they are much less effective.
Lets try a reality check. Bolton Paul Defiant fighter vrs Hurricane. about a 2000lb difference in flying weights. Granted the Hurricane had eight forward firing guns but it was carrying about 2670 rounds of ammo compared to the 2400 rounds in the Defiant. Defiant also carried about 25 imp gallons more fuel.
Perhaps 500lbs per gun if mounted in a turret and manned by a crew member who had no other duties? Like radio operator, navigator or Flight engineer or?
And this is for the turret mounted guns. Non- turret mounted guns weigh how much? But they are much less effective.
The 8,8 (56 cal barrels) formed the bulk of Luftwaffe heavy Flak force (80% ? in 1944, but perhaps 90-95% in 1942). I'd venture to say the bomber cruising at 25K has much better chance to avoid heavy Flak guns than one flying at 20K.
