Why did Britain give up on the Avro Manchester bomber?

[davebender]

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.

 

[Shortround6]

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

Why throw good money after bad?

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.

 

[Marcel]

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.

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

 

[parsifal]

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

 

[Glider]

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).

 

[davebender]

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.

 

[razor1uk]

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

 

[Shortround6]

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.

 

[davebender]

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.

 

[Glider]

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..

 

[Shortround6]

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.

 

[Milosh]

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.

 

[tomo pauk]

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?

 

[davebender]

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?

 

[Shortround6]

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

 

[tomo pauk]

Thanks

 

[davparlr]

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.

 

[davebender]

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

 

[fastmongrel]

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.

 

[Shortround6]

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