# Why did Britain give up on the Avro Manchester bomber?



## davebender (Mar 22, 2011)

Avro Manchester - Wikipedia, the free encyclopedia
Cruising speed was to be a minimum of 275 mph at 15,000 feet

75 to 100 mph faster then a Lancaster. A huge improvement in bomber survivability.

Why didn't Britain continue development of the Avro Manchester until it worked? Replace the RR Vulture engines with Napier Sabre engines. According to Wikipedia the Sabre engine was producing 2,400 reliable hp by 1944. The RAF might wind up with a fast heavy bomber equivalent to the almost produced Junkers Ju-288.


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## Shortround6 (Mar 22, 2011)

davebender said:


> Why didn't Britain continue development of the Avro Manchester until it worked?



Why throw good money after bad? 



davebender said:


> Replace the RR Vulture engines with Napier Sabre engines. According to Wikipedia the Sabre engine was producing 2,400 reliable hp by 1944.



Which is over two years too late. England wanted/needed heavy bombers in late 1941/early 1942. A super bomber that doesn't show up until some time in 1944 isn't going to do the job in 1942 or 1943.

As the war went on the Merlins used in the Lancaster progressed to where they were giving over 1600hp for take-off and about 1500hp at 9,000ft. The 2400hp Sabre was rated at either sea level or 2000ft (IIB or IIC engines) but only 2010 or 2065 hp for take-off. Power at altitude was 2045hp at 13,750ft. 

I would be a little leary of some of the information in WiKi unless double checked. For instance in the article on the sabre engine. 

"...by June 1940 when the Sabre passed the Air Ministry 100-hour type-test, the first production-ready versions were delivering 2,200 hp (1,640 kW) from their 2,238 in³ (37 L)[1]. By the end of the year, they were producing 2,400 hp (1,800 kW). To put this in perspective, the contemporary 1940 Rolls-Royce Merlin II was generating just over 1,000 hp (750 kW)."

The Merlin II was out of production in 1940, it had been replace by the Merlin III which, while essentially the same had a different propeller shaft, if a plane had a Rotol airscrew it had a Merlin III engine. It also had been cleared for around 1300hp and 12lbs of boost in the spring of the year. By the end of 1940 Spitifres IIs were being fitted with Merlin XIIs (1280hp at 10,500ft), Hurricanes were receiving Merlin XXs and with Spitfire MK Vs going into service squadron service in Feb, 1941 with Merlin 45s I would be willing to bet that Merlin 45s were running on test stands in 1940. These engines were comfortably into the 1300hp area if not beyond in 1940. the " contemporary 1940 Rolls-Royce Merlin II was generating just over 1,000 hp" statement is just so much hokum.


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## Marcel (Mar 23, 2011)

davebender said:


> Avro Manchester - Wikipedia, the free encyclopedia
> Cruising speed was to be a minimum of 275 mph at 15,000 feet
> 
> 75 to 100 mph faster then a Lancaster. A huge improvement in bomber survivability.
> ...


They didn't give up, the Lancaster is just a Manchester hull with new wings designed to carry 4 instead of 2 engines.


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## parsifal (Mar 23, 2011)

I am a bit puzzled as to what niche the type would fulfil.....the Lanc was basically a truck, carrying the heaviest loads of any bomber in the war. At the other end of the spectrum was the Mossie, that could evything a souped up manchester could do, only better. I cant see the need to spend a lot of effort on a proven loser, when you have proven winners, and sooner


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## Glider (Mar 23, 2011)

To be fair to Wikli it does give a max speed of 265mph. It also says this about the engine _When developed in 1935, the engine had promise — it was rated at 1,760 hp (1,310 kW) - but it proved woefully unreliable and had to be derated to 1,480-1,500 hp (1,100-1,120 kW). _


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## davebender (Mar 23, 2011)

> Lancaster is just a Manchester hull with new wings designed to carry 4 instead of 2 engines


Everything I have read suggests Lancaster cruise speed with payload was only about 180 mph. That makes it much easier to intercept then an aircraft cruising at 275 mph.

If the Manchester can be made to perform to specifications, which may or may not be possible, it would be far more survivable then a Lancaster bomber.


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## razor1uk (Mar 23, 2011)

Assuming it could have been tweeked enough to meet spec, yes it would have higher speed and so possible have better survivability stats.
But I think the number of losses for lanc would still have been more for the manc, since if it looses one engine, it would at best I think, be a powered descent/glide, whereas the lanc would still have 3 engines. I thnk its average loaded cruising speed wouldn't have been much better than a lanc, let alone in clean config' be able to get to 270+mph IMHO.

But I understand (hopefully) what your thinking/meaning, if there were reliable large engines for the manc, the lanc could have been 'the wierd one' like the He-177B/277 is to Goerings Lighter


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## Shortround6 (Mar 23, 2011)

davebender said:


> Everything I have read suggests Lancaster cruise speed with payload was only about 180 mph. That makes it much easier to intercept then an aircraft cruising at 275 mph.
> 
> If the Manchester can be made to perform to specifications, which may or may not be possible, it would be far more survivable then a Lancaster bomber.



Basically there is zero chance of the Manchester meeting that specification, without some rather major modifications. While the Lancaster had 10feet more wing and 2 extra engine nacelles it usually had 50% more power than the Manchester, which ought to cover the extra drag. Now if you can use a more streamline canopy, get rid of the nose and tail turrets in addition to the top turret, cut the crew to 3-4 and perform some other surgery to the plane you just might make it. 

You may also want to check the cruising speed of the Lancaster again, there may be some confusion as to indicated airspeed and ground speed. a Plane doing an indicated 180mph at 15,000ft will be doing close to 210mph over ground. Not 275mph but then the 275mph wasn't indicated airspeed either. 
For a further reality check try comparing the Manchester to the American B-26 bomber. The Early B-26 could carry 3,000lbs at 265mph all of 1000miles. It had a 602 sq ft wing compared to the Manchesters 1131 sq ft wing and weighed as much loaded as the Manchester did empty. It was using 1850hp engines.


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## davebender (Mar 23, 2011)

> While the Lancaster had 10feet more wing and 2 extra engine nacelles it usually had 50% more power


4 x RR Merlin XX V12 engines @ 1,280 hp = 5,120 total hp
2 x Sabre engines @ 2,400 hp (assuming they work) = 4,800 total hp.

I am not thinking in terms of replacing the Lancaster bomber. That aircraft fills an immediate wartime need. Assuming it works, the Manchester would be the follow-on bomber ILO the Avro Lincoln. Per Wikipedia, the Lincoln had a cruising speed of only 215 mph. That's not much of an improvement over the Lancaster and woefully inadequate for a late WWII bomber.


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## Glider (Mar 23, 2011)

davebender said:


> Everything I have read suggests Lancaster cruise speed with payload was only about 180 mph. That makes it much easier to intercept then an aircraft cruising at 275 mph.
> 
> If the Manchester can be made to perform to specifications, which may or may not be possible, it would be far more survivable then a Lancaster bomber.


 
An aircraft with a max speed of 265 mph isn't going to have a cruising speed of 275 mph. The Spec may have said a cruising speed of 275 but none of the contenders came close and the Manchester had a max speed of 265mph..


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## Shortround6 (Mar 23, 2011)

Try doing the math again, by the time the Sabre gave 2400hp reliably the Merlins in the Lancaster were giving about 1635hp for take-off. 4 X 1635= 6540hp. 
Depending on the Sabre it might, or might not have2400hp for take off. The Sabre IIB was rated at 2010hp for take-off. 2 X 2010=4020hp.

What might be more interesting is the power at altitude and not necessarily the 5 minute rating. 

Merlin 24/224 was good for 1175hp at 17,500ft for 30 minutes I believe. 4 X 1175= 4700hp
Sabre IIB was good for 1735hp at 17,000ft. 2 X 1735=3470hp

You simply have to quite relying on Wikipeadia as a source. 215mph is the MOST ECONOMICAL cruising speed at 20,000ft. It certainly wasn't the only one let alone the fastest. A Lincoln could carry 14,000lbs of bombs 2240 miles at 260mph at 20,000ft. Slowing to the 215mph mark added 400 miles to the range. A Lincoln running light (at 63,500lbs) could touch a 270mph cruise at about 23,000ft.


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## Milosh (Mar 23, 2011)

davebender said:


> Everything I have read suggests Lancaster cruise speed with payload was only about 180 mph. That makes it much easier to intercept then an aircraft cruising at 275 mph.
> 
> If the Manchester can be made to perform to specifications, which may or may not be possible, it would be far more survivable then a Lancaster bomber.



Gee, that is the same cruise speed as the B-17s and B-24s flew.

So Dave, how was the Manchester to get another 100mph over its maximum speed?

Oh, and the Sabre was still having some engine reliability problems in 1944. Nothing like loosing an engine on a twin engine plane especially on take off with a full bomb load.


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## tomo pauk (Mar 23, 2011)

After reading about bombload vs. range vs. cruise speed: 
is there a good table available, that would make easier to compare bombers on that combination of capabilities?


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## davebender (Mar 23, 2011)

Let's approach this from another angle. 

The He-177 design was somewhat similiar to the Avro Manchester. Total He-177 engine power was less then a late war Lancaster or Avro Lincoln with 1,635hp engines. Why was the He-177A5 heavy bomber so fast?


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## Shortround6 (Mar 23, 2011)

You need a different chart (or charts) for each bomber. A nice on-line article about the Lincoln (with a few simple charts) can be found here: lancaster | 1946 | 0103 | Flight Archive


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## tomo pauk (Mar 23, 2011)

Thanks


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## davparlr (Mar 24, 2011)

davebender said:


> Let's approach this from another angle.
> 
> The He-177 design was somewhat similiar to the Avro Manchester. Total He-177 engine power was less then a late war Lancaster or Avro Lincoln with 1,635hp engines. Why was the He-177A5 heavy bomber so fast?


 
The data I dug up on the Lanc mk I was 1469 hp Merlin XXs for total of 5840 hp and a top speed of 281 mph.

The He-177A-5 had two 2950 hp DB 610B engines for a total of 5900 hp and a top speed of 303 mph.

That's not a lot of differences and then when you consider the Lanc has a larger cross sectional area including a deeper fuselage and two additional engine modules, everything seems reasonable.


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## davebender (Mar 24, 2011)

That doesn't sound right. Several web sites mention He-177A5 max speed of 351 mph @ 6,000 meters.


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## fastmongrel (Mar 24, 2011)

A fairly old book I have (Axis Aircraft of WWII by David Mondey) quotes an economical cruising speed of 350 kilometers per hour at 6,000 meters for the A5/R2 version that converts to 218 mph at 19,685 feet. A top speed of 490 km/h or 304 mph is quoted but no altitude is given. Possibly Wiki has got the numbers mixed up I wouldnt be surprised it usually does.


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## Shortround6 (Mar 24, 2011)

Try another web site besides Wiki.

Or try common sense, 
He 177, 1098 sq ft of wing, 56,000-60,000lbs weight and even we allow for 3100hp at 2000meters or so?
A-26, 540 sq ft of wing, 27,600-30,000lbs weight and two 2000hp engines=355mph. 
Or look at P-61 Black Widow. 366mph at 20,000ft on two 2000hp engines. 
1/2 the airplane the He 177 was with 2/3rds the power. Must be the crummy allied aerodynamics


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## fastmongrel (Mar 24, 2011)

Shortround6 said:


> 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.


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## davparlr (Mar 24, 2011)

davebender said:


> That doesn't sound right. Several web sites mention He-177A5 max speed of 351 mph @ 6,000 meters.



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.


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## parsifal (Mar 24, 2011)

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


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## davebender (Mar 24, 2011)

> 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


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?


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## parsifal (Mar 24, 2011)

well, in the case of the he177, i would say yes, but not by much


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## Shortround6 (Mar 25, 2011)

davebender said:


> 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?



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.


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## Milosh (Mar 25, 2011)

davebender said:


> 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?


 
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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## davebender (Mar 25, 2011)

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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## davebender (Mar 25, 2011)

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.


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## tomo pauk (Mar 25, 2011)

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.


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## Milosh (Mar 25, 2011)

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.


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## parsifal (Mar 25, 2011)

davebender said:


> 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.




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


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## Shortround6 (Mar 25, 2011)

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.


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## davebender (Mar 25, 2011)

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.


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## davebender (Mar 25, 2011)

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.


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## Shortround6 (Mar 25, 2011)

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.


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## pbfoot (Mar 25, 2011)

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


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## tyrodtom (Mar 25, 2011)

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.


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## Shortround6 (Mar 25, 2011)

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.


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## tomo pauk (Mar 25, 2011)

Shortround6 said:


> 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.



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.


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## tomo pauk (Mar 25, 2011)

As for concept of fast bomber, while it backfired in day ops, it was very workable for night ops. The night fighters were inherently heavier draggier than day fighters ( usually 2-3 seaters, antennae sets for Luftwaffe types, heavy armament), so most of them resembled performed more akin to bombers, than common fighters. Too bad Americans didn't built (X)B-38s (with turrets replaced by single HMGs, no waist guns) for RAF Bomber command.


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## Shortround6 (Mar 25, 2011)

tomo pauk said:


> 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.


 I am not sure about German practice but by 1944 allied practice/terminology was the that effective ceiling of the AA gun was the altitude at which a 300mph airplane could be engaged for 20 seconds. Yes, a plane flying at 20,000ft can be engaging for a longer period of time or by guns further to side of it's flight path than a plane flying at 25,000ft. The higher altitude will increase the difficulties of the AA defense but will not grant immunity just as a higher cruising speed increases the interceptor fighter's difficulties but does not grant immunity. The price of these performance gains in order to secure large performance increases (on the order of the Mosquito for example) may be not only no defensive armament but lower bombloads, shorter range which need more missions to deliver the same tonnage of bombs.


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## tyrodtom (Mar 25, 2011)

The only turret i've found the weight on is the Sperry ball turret, as installed in the B-17, 1200lbs, with gunner, who had to be a small guy.
They were thinking about eliminating the belly turret late in the war, that's the weight they figured it would save. That 1200lb wouldn't include the extra structual reinforcement added in the fuselage for that turret or the extra generating capacity to power it, or the extra life support sytems for the gunner.
The belly turret in the B-24 would be even heavier, it was retractable.
My wag estimate of 1000 lb per gun might be a little too much, some of the gunner positions was performed by crewmembers with other functions also.


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## tomo pauk (Mar 25, 2011)

Hi, shortround6,
You can note that I was proposing deletion of turrets, to save both on weight and drag. As you've stated, the weight reduction is 500lbs per power-turreted gun, so deletion of 3 turrets (8 guns total) yields 3000-4000 lbs of weight saving. The part of that saving is canceled out by replacing the turrets with gunner single MG (twin MG for stern position? weight 300 lbs per position?; 1000 lbs total), so we save perhaps 2000-3000 lbs.


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## Shortround6 (Mar 25, 2011)

that and British turrets often had four .303 guns which is what really throws the weight per gun thing off.


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## pbfoot (Mar 25, 2011)

quoted from Mike Lewis DFC CD one of the first Manchester pilots 207 Sqn quoting about Manchester 1A "the mid upper turret on the Manchester never did function properly. When rotated it set up a disconcerting vibration in the airframe. The AirMinistry finally circulated aletter permitting the squadrons and Avro to remove the turret if desired . I always had the mid upper removed from my aircraft removed from my aircraft giving me an extra 10 mph and improving single engine performance immenesly `` Mike Lewis did 2 tours on Manchesters


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## tomo pauk (Mar 25, 2011)

Truth to be told, that turret itself seem like the draggiest ever produced.


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## Shortround6 (Mar 25, 2011)

tomo pauk said:


> Hi, shortround6,
> You can note that I was proposing deletion of turrets, to save both on weight and drag. As you've stated, the weight reduction is 500lbs per power-turreted gun, so deletion of 3 turrets (8 guns total) yields 3000-4000 lbs of weight saving. The part of that saving is canceled out by replacing the turrets with gunner single MG (twin MG for stern position? weight 300 lbs per position?; 1000 lbs total), so we save perhaps 2000-3000 lbs.



I think you either keep the power turrets (and get them to work) or you design a new plane without the gun stations. Pulling turrets out of an existing airframe and plating over the holes saves weight but doesn't save a whole lot on drag. Some, maybe, but not as much as a new thinner airframe. They went to turrets because hand held guns didn't work very well. Difficult to aim in a several hundred mile an hour slipstream and in many cases the hand held guns had limited ammo capacity. IF 4 power driven .303s won't bring down an enemy fighter (80 rounds a second) then a single Vickers K gun (18 rounds a second?) isn't going to do much good on average. 
Going from a cruise of 215-240mph to even 265mph is not going to stop the fighters from intercepting a large portion of the time. You need to get to 300mph plus and be able to keep it up for for 1/2 hour to hour at a time (or longer?) just ripping a couple of turrets out of an existing design isn't going to do it. As far as twin .303 out the back in hand held mounts try checking the record of the Handley Page Hampden. Early Wellingtons used twin powered "mounts" that weren't really turrets. The gunner did not sit in with the guns and turn with them. Some early American bombers had Manual tail guns, like the early B-26s. If you are going to ruin the lines of the fuselage by making the tail big enough to hold a man and you are going to stick 200lbs of man and chute, 100-200lbs of guns and ammo (more if they are .50s), commo equipment, oxogen, suit heating, etc you might as well go whole hog and stick in the power turret and drastically change his chances of actually hitting something.


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## tomo pauk (Mar 25, 2011)

The reason I'm not proposing ditching the defensive MG posts all together is not because I think that hand-aimed MGs would be good replacment, but because the observer checking around is good to have on night bomber. So since we have observers in lieu of crewed gun turrets, me might have a MG by himself. Since I've proposed re-engining the Manchester too, that, coupled with 1+ ton weight saving (gained by deletion of turrets) mean something for performance.

And now, I'd order some Mossies for upcoming bomber missions vs. Germany.


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