The Heinkel HE177

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Dave Saxton
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The Heinkel HE177

Post by Dave Saxton »

The HE177 was a four engine bomber that had a long agonizing development beginning in 1938 and ultimately failed to become the operational weapon, that the Germans were counting on it to be. Its failed development meant that the Luftwaffe never had the strategic bomber it needed to successfully prosecute a major air offensive. More importantly to our interest here, it was badly needed by the Kriegsmarine and its absence in the war at sea was a factor to the inability to the German Navy to prevail in the war at sea. Other bomber aircraft such as the JU88, which un-expectantly became a very effective torpedo bomber, simply didn’t have the long range or the concentrated firepower needed by the Germans in the war at sea.

The HE177 was about the same size and weight of a Lancaster bomber. There are other parallels to Lancaster. The Lancaster, first known as the Manchester bomber, was originally a two engine bomber that actually used four engines by combining two v12 liquid cooled engines into a single x24 engine, each driving a single propeller. The twin engine Manchester became the quad engine Lancaster in 1941 when the British gave up on the combined engine concept and redesigned the bomber to feature four conventional v12 engines, each driving its own prop. The He177 also featured four engines combined into two engines each driving a single a propeller. Heinkel strongly suggested that the Luftwaffe also develop a four separate engine version of the HE177 in parallel as he didn’t think it would work, but the Luftwaffe would not accept that proposal because a four engine bomber could not be able to dive bomb. A maximum of two propellers was required for dive bombing to limit the propeller drag. The Germans, unlike the British, persisted for several more years trying to make the four engines driving two props concept work.

The dive bomber requirements had their genesis from war experience during the Spanish Civil War. It was noted that the accuracy of high altitude horizontal bombing was terrible while dive bombing was precisely accurate. The dive bombing requirement of a large bomber is considered ridiculous by aviation historians, but the attempt to provide the 177 with such capability eventually made it potentially a much more effective marine bomber against ships. The dive bombing requirement was eventually dropped, but not until September 1942. However, the aircraft, when it worked, could make attacks on naval targets approaching in a shallow dive and with an approach and retirement speed of 430 knots, and deliver specialized anti-ship weapons with great precision. It overcame the biggest problem of using large bombers against ships: large bombers such as the B-17, for example, rarely scored hits against targets at sea.

Nonetheless, the HE177 never really arrived at the operational level at the disposal of Fliegerfueheratlantic or Luftflotte 5 in Norway in time or in numbers to have any impact on the war at sea.

The problems that caused such elongated development stemmed mostly from the unconventional engine arraignment. Originally the concept was to provide two Daimler Benz v12 engines one in front of the other driving a contra rotating prop. However, no such design existed, but a design featuring two v12 engines side by side and driving a single prop through a gear box did already exist. The Daimler Benz 606 Power System with side by side engines was adopted. Ventilation and engine cooling was insufficient and engine fires were common. Moreover, it was a nightmare to service the engines. Even to change the spark plugs required much disassembly of the engines. An additional, problem was that Heinkel engineers had miscalculated the required strength of the wings by about 1/3. By the time these problems were ironed out, but serviceability of the engines still remained poor, the war situation had out stripped the window of opportunity that the bomber could effectively be utilized. There remained no effective long-range German escort fighter, and by that time of the war there was a shortage of both aviation fuel and bomber crews, as fighter aircraft defense of the Fatherland was at a crisis point.

Nonetheless, when the late model HE177 flew trouble free it was capable of impressive performance. Despite the extra weight stemming from strengthening the wings, airframe, and landing gear, it exceeded the original design performance specifications by a wide margin. Maximum level flight speed was in excess of 350 knots and range exceeded 3,000 nautical miles. This is performance comparable to that of the B-29. The anti-ship versions HE177 could deliver six metric tons of anti-ship ordinance that included HE and/or armour piercing bombs, or up to three anti-ship guided missiles, or torpedoes, or mines.
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Re: The Heinkel HE177

Post by wadinga »

Hi Dave and All,

The Heinkel 177 or "Flaming Coffin" as it was affectionately known by its crews :shock: was indeed a dead end. Mr Heinkel personally told Udet , a dive-bombing specialist, that a plane twice as heavy as a Ju88 couldn't be a dive bomber, but the latter shrugged his shoulders and said that Jeschonnek, Goring and the Furhrer required it. It was the limited 1,000 hp Daimler-Benz 601 power output which meant more engines and yet the low drag requirement meant no additional nacelles, so they were crammed into two nacelles only with cramped pipework and a no radiators but instead an unreliable evaporative cooling system.

Despite the test prototypes either falling to pieces on pull-out, or bursting into flame through fractured piping the production model went into production in Dec 1941 with improved DB 606 and radiators. Some were used as transports for Stalingrad in 1942 with 7 bursting into flames. However continued gross unreliability meant that the first serious operational use was in November 1943 when 20 He 177s deploying Hs 293 missiles were used to attack a convoy with little success.

Fw 200 Condors soldiered on as the only reliable Luftwaffe long range maritime aircraft, but with inherent structural weakness caused by war-stressing an essentially civilian airliner design. In 1944 He 177 strategic bombers attacked the UK in penny packet numbers, but by mid 1944 they were launching 90 aircraft raids on the USSR. Chronic fuel shortages meant (such a raid used 480 tons of fuel, a whole days' August 1944 production) sent the aircraft back to Germany for lay-up and to deploy crews and resources in fighter defence of the Reich.

My sources say a maximum speed of only 303 mph.

The Luftwaffe tried to produce several multi-engine designs besides the four nacelle He 277 variant. The Messerschmitt 264 was the prettiest, with a tricycle undercarriage, Superfortress style nose and fuselage, Lancaster tail and four and six engine/nacelle variants and designed to bomb not only the UK but the US East Coast. Like the He 177, the bickering, competition and bone-headed stupidity inherent in the Nazi system made it a failure too.

Whereas the double engine, drive-shafts clutched together, "bodge-up" of two DB 601s was never a success, the X-24 cyl Rolls Royce Vultures which were supposed to power the Manchester were a much more sophisticated solution. Two V-12s, one inverted, would drive the single crankshaft to get 2,000 horsepower. However, unreliability ensued, so the tried and true Merlins, four per aircraft powered the mighty Lancaster. (Expecting to see one fly Saturday at Flying Legends, Duxford.) :D

All the best

wadinga
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Re: The Heinkel HE177

Post by Paul L »

just a point 350 knots is 640 kph , which is 395mph....perhaps it was mph not knots?
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Re: The Heinkel HE177

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I don't see that an operational HE 177 could have been of much use to the KM. Italian experience of using high level bombers in the Med illustrates that it would not be an accurate weapon against ships. Its possible use as a dive bomber I find difficult to take seriously.

What the KM really needed was a long range torpedo bomber (apart from a large air arm with completed carriers). Again the Italians could have given them an answer, with the SM 79.
Last edited by RF on Fri Jul 07, 2017 9:06 am, edited 1 time in total.
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Re: The Heinkel HE177

Post by RF »

Dave Saxton wrote:The HE177 was a four engine bomber that had a long agonizing development beginning in 1938
Work on a long range strategic bomber should have been started a lot earlier than 1938.

Failure to develop such a weapon was in my view one of the major strategic military blunders by Hitler.
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Re: The Heinkel HE177

Post by wadinga »

Dear RF and All,

The torpedo bomber variants of the He 111 and the JU 88 were as least as good as the SM79. Better AA outfits and carrier CAP meant big torpedo bombers were obsolete by mid-war.

The low drag of the He 177 did allow a shallow dive technique to get it up to nearly 400 mph, (assuming the wings didn't fall off on pull-out) but the highest speed in level flight I have seen recorded is 317 mph.

Having 24 big-ends thrashing around a single crankshaft gave the Vulture plenty of reliability problems, but the British used an H-24 layout of the Napier Sabre used in Typhoon and Tempest fighters which was much more successful having two boxer format stacked above each other with separate crankshafts.

The numerous failures of chaotic Luftwaffe aircraft development programmes mid-war under his control caused Udet to commit suicide, but Jeschonnek, Goering and several others were equally responsible. German strategic bombing policy was to have many, many medium bombers rather than fewer big bombers, but the main Luftwaffe role was to help the army capture territory, not engage in long range bomber war. Strategic bombing was to be used on those who couldn't strike back eg Warsaw, Rotterdam etc because they didn't have a bomber force.

All the best

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Re: The Heinkel HE177

Post by RF »

wadinga wrote: , but the main Luftwaffe role was to help the army capture territory, not engage in long range bomber war. Strategic bombing was to be used on those who couldn't strike back eg Warsaw, Rotterdam etc because they didn't have a bomber force.
From 1939 essentially the role of the Luftwaffe was one of interdiction for the Heer, a role largely incurred by default. As I understand it the original idea of the Luftwaffe was obliteration of enemy cities but the means of achieving this were not compatible with the early types of aircraft that were developed. No proper strategic planning was purposefully done, instead there was the whim of the Fuhrer, misdirection by Goering and engineers left to get on with conflicting and confused objectives.

Strategic bombing was attempted by the Luftwaffe on Britain during the blitz; but the attack was too lightweight and after a few months petered out due to Operation Barbarossa.

Essentially what the Third Reich needed was a long range strategic bomber force, with a mix of medium and heavy bombers that would allow interdiction support for the Heer and the KM as well as long range bombing. That requires leadership - which the British and Americans had, the Axis as a whole didn't.
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Re: The Heinkel HE177

Post by Dave Saxton »

Hi all,

I apologize for my absence. I have been very busy of late.

Authoritative sources, including Groehler, list the HE-177A-5 as having a level flight top speed of 351-355 mph (mph not knots, the error was mine as I'm used to using knots in modern aviation). A 303 mph figure is correct for some of the early prototypes. The A5 versions and some of the A3 versions got the much more powerful and more reliable DB610 power systems. The structural problems were also apparently put right with the A5 versions and consistent shallow dive attack techniques could be safely undertaken. I was somewhat surprised that the late model versions appear to be highly regarded among knowledgeable aviation historians. They apparently finally got it working, but it was far too late.

The A5, which Heinkel considered the only acceptable production variant, only began production in Feb 43 and did not become operational with a training squadron until Sept 43. By the time the marine version HE-177A5/R/2 was available for war operations the U-boats had been defeated, the Scharnhorst sunk, Allied air superiority complete over the sea lanes, and bomber pilots and aviation gasoline stocks were required to be redeployed to fighters.
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Re: The Heinkel HE177

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RF wrote:
wadinga wrote: , but the main Luftwaffe role was to help the army capture territory, not engage in long range bomber war. Strategic bombing was to be used on those who couldn't strike back eg Warsaw, Rotterdam etc because they didn't have a bomber force.
From 1939 essentially the role of the Luftwaffe was one of interdiction for the Heer, a role largely incurred by default. As I understand it the original idea of the Luftwaffe was obliteration of enemy cities but the means of achieving this were not compatible with the early types of aircraft that were developed. No proper strategic planning was purposefully done, instead there was the whim of the Fuhrer, misdirection by Goering and engineers left to get on with conflicting and confused objectives.

Strategic bombing was attempted by the Luftwaffe on Britain during the blitz; but the attack was too lightweight and after a few months petered out due to Operation Barbarossa.

Essentially what the Third Reich needed was a long range strategic bomber force, with a mix of medium and heavy bombers that would allow interdiction support for the Heer and the KM as well as long range bombing. That requires leadership - which the British and Americans had, the Axis as a whole didn't.

Goering was a poor leader. Initially the Luftwaffe high command was functional because of the competency of Goering's two deputies, Wever and Milch. Wever had a way of ameliorating Milch's abrasiveness. When Wever was killed in an air crash during 1936 Goering's high command structure became dysfunctional. Everybody, including Goering, grew to dislike Milch and Milch was eventually isolated. This was good for the Allies because Milch was highly competent and most of his substitutes were not. Goering could not just get rid of Milch because Hitler much liked him.

Wever was the Luftwaffe's champion for the development of strategic bomber capabilities. There was a program from the beginning. Under Wever, four engine bombers development was undertaken. However, Germany did not have the resources to see this program though. It was unfeasible. A fleet of those bombers would have consumed more gasoline than Germany could produce. It was also anticipated that the DO19 (?) would be obsolete by the time it completed development. A truncated follow on program was started before Wever's death. This was the genesis of the much more advanced HE177. The original design specs were issued in 1936, with Heinkel building the first mock up in 1937. Heinkel began work on a flying prototype in 1938.

With Wever's death, and the retirement of technical office head Wimmer, their replacements Kesselring* and Udet, expressed no enthusiasm for building large, long range, bombers at all. This was the beginning of the Luftwaffe being built mainly as a support force for the Heer.

After war prematurely came upon them, Milch was always a champion of fighters, not bombers, because he understood the problems of resources and numbers between Germany and its enemies. However before the war, Milch and Goering did not buy into Kesselring's and Udet's no long range bomber plans. With the denial to the Kriegsmarine of having any air forces themselves (because Goering did not want any dilution of air resources beyond his direct control) a long range marine bomber and effective fighter escort for the marine bomber was a must.

Because of resource scarcity even Goering realized that Hitler's grandiose plans of a large air force were simply impossible. The plan proposed was to build around a core of just four aircraft types:

A single engine fighter (The Bf109)
A twin engine fighter (Me210)
A medium bomber (Ju88)
A large long range bomber for mainly marine applications (HE177)

Of these only the BF109 was initially successful. The JU88 eventually succeeded but two years behind schedule. It was understood that the JU87 Stuka, the HE111, DO17, and BF110 were already obsolete or soon would be no later than 1940. The failed development of the ME210 really hurt. The ME210 was to replace both the Bf110 and the Stuka. It was anticipated that the JU88 would need replacement by 1942, and the BF109 by 1941. Plans for the HE177 were modest. It was scheduled to become fully operational only by 1943 and with a total of only 500 aircraft.

*Kesselring begged reassignment because he could not get along with Milch. This is when Jeschoneck was brought in.
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Re: The Heinkel HE177

Post by wadinga »

Hi Dave,

In William Green "Famous Bombers of WWII" he devotes no less than 13 pages to the many variants of the He 177. Of all those he mentions, prototypes and production models, only the He 177 A-7, a specialist high-altitude bomber equipped with the DB 613, each giving take off power 3,600 hp, is credited with a speed as high as 335 mph at 20,000ft. Only 6 were built.

He tabulates the A-5/R2 with DB 610A-1 engines with maximum speed (normal loaded weight) 303 mph at 20,000ft. 248.5 mph at sea level. Alfred Price ( who knows a thing or two) says 270 mph max at 20,000ft. These figures are confirmed by J R Smith & Anthony Kay's German Aircraft of WWII. Maybe when we talk about max loaded, the external drag of 2X Hs 273 or a single Fritz X needs to be taken into account slowing speed.

You will be overjoyed to hear Green credits the 1944 Operation Steinbock shallow full power dive technique with achieving no less than 435 mph!!!! Even then 8 out of 13 raiders aborted with overheated/blazing engines. All the bomb load was internal.

As late as 20th July 1944 the eastern front He 177 were still suffering engine fires and after two out of 80 in a max effort raid passing Rastenberg had to dump their bombs before aborting/crashing with this problem, the KG1 commander Von Riesen was briefly under threat of court martial since it was thought at one stage the explosion at the Wolf's Lair might have been these discarded weapons. :shock:

The guided bombs/rockets needed more development to be become a useful anti-ship weapon and the continuing reliability issues affecting the French based maritime Gruppe meant flying the "luftwaffefeuerzeug" (Luftwaffe petrol lighter) out over the Atlantic was a risky business.

Interestingly, the Germans had operated a strategic "terror bomber" for attacks on London with a wingspan bigger than B-17 or Lancaster and only just smaller than a B-29.......................................... in WWI. :shock: Zeppelins, Gotha and the Giant R2 (4ft less wingspan than a B-29) bombers had killed 1500 in UK raids in the earlier conflict . In Germany, as you say, only Wever was a believer in big aircraft whereas all the rest of the Nazi and Luftwaffe hierarchy wanted numbers as they were mere bean counters



All the best

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Re: The Heinkel HE177

Post by Dave Saxton »

I believe Green and Price are in error here. 303 mph is attributed to an A1 prototype, though.
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Re: The Heinkel HE177

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Dave Saxton wrote:I believe Green and Price are in error here. 303 mph is attributed to an A1 prototype, though.

Aircraft speed is going to be dependent on aircraft mass and ordnance etc. The engine power figures are difficult since they change with altitude. So speed figures should include altitude mass & load status. In other wards each aircraft is going to have multiple 'max speed' figures.

What is meant by "normal loaded" weight? Most of the time top aircraft speeds are calculated based on 1/2 fuel in clean configuration ...ie not carrying any ordinance, but with 1/2 of the fuel...a fighter over the target?
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Re: The Heinkel HE177

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Paul L wrote:
Dave Saxton wrote:I believe Green and Price are in error here. 303 mph is attributed to an A1 prototype, though.

Aircraft speed is going to be dependent on aircraft mass and ordnance etc. The engine power figures are difficult since they change with altitude. So speed figures should include altitude mass & load status. In other wards each aircraft is going to have multiple 'max speed' figures.

What is meant by "normal loaded" weight? Most of the time top aircraft speeds are calculated based on 1/2 fuel in clean configuration ...ie not carrying any ordinance, but with 1/2 of the fuel...a fighter over the target?
Of course. The 350 mph speed for the Heinkel and Approx. 285 mph speeds for the B17 and the Lancaster are using more or less the same criteria. The late model Heinkel is a much cleaner aircraft aerodynamically with significantly more thrust than those iconic Allied bombers though. The A7 should be a bit slower than the A5 due to the different wing designs.
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Re: The Heinkel HE177

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Hello Dave and all,

Paul L is undoubtedly correct, and I am prepared to accede that some combination of load and altitude might allow higher speeds. This is horribly similar to the lengthy wrangles over whether what maximum speed Bismarck did or even could have done in trials conditions have any relevance as to what she might have actually achieved during her first and last combat mission in heavy Atlantic swells, with some damage etc etc.

Green's comprehensive coverage gives details of a vast array of sub-types including the 1944 He-277B-5 R2 (alias He-177 B-5 R2) which had four separately nacelled DB-603A engines and is credited with 354 mph but a cruising speed of 286 mph. He does not state whether this was achieved at the impressive service ceiling of 49,200ft and/or something below the maximum loaded weight of 98,105 lbs. He also points out that external stores of a 5,500lb bomb and Hs 293 missile and 2 Fritz-X guided bombs could be carried, but does not mention whether all these Christmas tree ornaments dangling off it would have slowed it down. Only 8 were built and only 2 or 3 test flown.

Dr Heinkel had to hide the development of the 4 nacelle aircraft under the He-177B moniker because Goering had forbidden any further work on Heinkel's 277 idea. Nazi stupidity meant that the "two nacelle dive bomber" would be the only way forward. The He-177A-4 was the first 4 nacelle design and it was estimated it would have a maximum speed of 350 mph but wasn't built. A further secretive development was called the He-274V1 and given to a French company to work on with estimated performance of 267 mph at sea level, 310 at 18,700ft, and 373 mph at 36.000ft. It only flew after the war.

As I mentioned below only 6 of the high speed high altitude 335mph He 177 A-7 were built. The Japanese were interested in producing them and one was readied for a flight over the USSR, but they decided this would enrage the Soviets (Japan was not aggravating them) and an alternate routing was not available, so it didn't happen. This was not a production model.

I note the latest comment about "thrust". It is clear that whatever horsepower the coupled engines generated, two propellers were not enough to utilize it and all the four nacelle variants built or proposed were apparently faster. :D

Green's representative model for the summary table is the He-177A-5/R2 for which he gives 303 mph at 20,000ft at normal loaded weight of 59,966lbs or 273mph at maximum loaded weight of 68,343 lbs at 20,000ft. He gives a service ceiling of 26,250ft for this model. Engines DB-610A-1 or B-1 opposite handed. This is the production model eg used for the convoy attacks by II/KG 40 Nov 21, 1943.

BTW this is not in any way a putdown, and I only mention it because noticed a similar fluff in a UK national paper recently. Ordnance is shells or bombs but ordinance is an authoritative legal or religious instruction. If the government drops an ordinance on you it's bad, but if it's ordnance it's really bad. :cool:

All the best

wadinga
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Re: The Heinkel HE177

Post by Paul L »

thanks for the correction on ordnance & ordinance .

Speed at altitude figures for fighters are well known- but they all feature a "chevron" graph covering speed vs altitude. so for all aircraft - top speed depends on altitude and various add-ons like supercharger and fuel quality and engine RPM.

http://i1032.photobucket.com/albums/a40 ... d428df.jpg


http://www.spitfireperformance.com/spit9v109g.html


http://www.rkka.es/aviones/diagram/02_027/02_027.gif

these figures apply to bigger aircraft too....

http://i.gyazo.com/a11318b413538bdc248b69003176baf3.png

http://www.wwiiaircraftperformance.org/ ... -fig2e.jpg

http://www.wwiiaircraftperformance.org/ ... -chart.jpg

http://www.wwiiaircraftperformance.org/ ... rmance.pdf

page 14-16 has the chevron graphs

http://www.wwiiaircraftperformance.org/ ... istics.pdf

note page 5 with graphs shows the speed vs altitude chevron for B-17G


never seen any graphs for Nazi bombers like HE-177.
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