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The Jumo 222 project failed to produce a reliable engine (although a small number of engines were produced), while the DB 604 was cancelled in September 1942. This left Junkers searching for suitable engines, and relying on under-powered BMW 801 radial engines to power the prototypes.
German sources indicate the problem wasn't the engine as originally designed, it was that as it was getting production ready Erhard Milch upped the power output requirements, so they had to go back to square one and redesign the engine to accommodate that. At the same time Milch also change the requirements of the Ju288 itself. It seems he got into a power struggle with the head of Junkers, a guy named Kloppenberg, who under Udet had effectively been given control over bomber production. Milch, taking over once again after Udet committed suicide, needed to sabotage Kloppenberg's key project to reassert control over production, so changing the requirements sufficed to do that. Meanwhile after raising the output requirements again the engine was finally production ready in 1944 (the E/F series of the 222) when it was too late to put it in production, but US testing showed that it worked just fine, but was superseded by jet engine developments.This sums up why pretty succinctly.
One or two (?) prototypes were powered by the Jumo 222 but they were unreliable and fitted with the BMW 801 it was badly underpowered. To get that startling performance you have to get the Jumo to work reliably enough for production. They simply cannot within the timeline specified. The impressive performance figures are estimates only, so not borne out of reality. The Bomber B was arguably too ambitious for the German industry as it was at the time.
The Bomber B wasn't actually too ambitious, it simply ran afoul of a power struggle.
I actually found the report on it in a magazine, here are a series of British reports on it:I didn't know about the Americans trialling the Jumo 222, thanks for that information, but I have to disagree with your statement above, it's a simplistic brush over the technical issues the bombers faced. The Jumo 222 was not the only engine that was stipulated, the DB engines suffered delay too. If it were as simple as a power struggle, at least one type would have gained favour and further investment, but the fact was, the entire programme ran behind schedule and development of all the aircraft was protracted - the Dornier not being able to match performance stipulations, the Fw 191 being overly complex - the Germans had not sufficiently developed power operated turrets before the Bomber B yet the designs called for remotely operated electric turrets, which as it turned out never worked as they needed them to, not to mention the Fw 191's power system being too problematic despite the airframe being sound (airframe design seemed a highlight, it was the niggling details that held things up), the Arado design was never actually completed at all...
The Ju 288 was planned for mass production and a variety of different variants was planned; it should have had a bright future, but power struggle or not, there was more to the proposal's end than personality disagreements. In saying that, the Luftwaffe was definitely hampered by power struggles, the He 177 included along with its technical issues, equally illustrative of the fact it was ambitious...
In March 1943, Goering spoke to the heads of various departments and firms at Carinhall, including Milch, Hertel of Junkers, Ernst Heinkel, Willi Messerschmitt et al., where he ranted for some time about the state of the industry and that they couldn't get their bombers to work, even going so far as to state that he considered blindly copying the best British four-engined bomber. Now, whether he was serious or not is probably not worthy of conjecture, but what this illustrated was that there were problems throughout the entire industry; major German aircraft programmes were failing, He 177, Bomber B, Me 210 etc and he wasn't happy and demanded improvement.
The mere fact that the Ju 88, Bf 110, He 111, all pre war designs were still in frontline service at the end of the war illustrates that the Germans definitely had a supply problem beyond power struggles.
I'm afraid its more complicated than simply getting the Jumo to work...
AFAIK the undercarriage issue was a function of the increased weight resulting from Milch's spec changes to delay the project. The crashes were a function of the problem of increased weight and either underpowered or overweight different engines. Again sabotage through spec change.The Ju 288 had a few mechanical issues, the first prototype's undercarriage didn't lock down properly, it's worth mentioning that out of 22 examples built, 17 crashed at some stage of their lives, not a good outcome, really. With the Technisches Amt changing specifications to increase crew from 3 to 4 and load carrying ability, which resulted in lengthened wingspan, weight creep became an issue and that sparkling performance, estimated only, was becoming further out of reach, even with the Jumo engines.
It was delayed by about a year and when it was ready Milch changed the spec to accommodate the increased airframe weight that he also ordered. So to meet the new spec the design team had to make substantial changes to the engine, which of course set back development. The DB606 engine was considerably heavier and largely and had the problem of bursting into flame.Also, as SR stated above, regarding the Jumo 222, exactly how much was personnel issues and how much was mechanical? The first engine certified for flight was delayed by 1 and a half years, a long time for such an important specification (was this because of personnel issues?), and with a maximum of 2,200 hp at 5,000m, which is impressive but is not hitting the numbers, and the DB 606 offered greater, 2,650 hp at just under 5,000 m according to one source I have.
Huh? The reason the bore was changed was due to the increased power Milch's new spec demanded. The later E/F engines relied on a new supercharger and aftercooler to hit spec, not increased displacement like the failed other attempts in the C/D series. From what I can find the original A/B worked just fine with the original spec by the time Milch raised the power output spec.Kay from Putnam's Junkers Aircraft states that the engine required further development in later variants which included a greater bore and stroke to increase power, which in the C and D variants was considered unsatisfactory. The later E and F engines retained the original bore and stroke but had greater capacity - this kind of work isn't indicative of a personnel clash, it is indicative of an engine refusing to do what the manufacturers claimed it could. The fitting of the DB606 required extra structural strengthening to the airframe, which obviously added weight and eroded performance even more, and like the Jumo, proved unreliable and was heavier by over 400 kilograms.
Agree to disagree given that your interpretations don't fit the facts.The more I read about this programme the more it becomes apparent that the whole bomber B endeavour was beset by wishful thinking and is subject to the usual would'a could'a should'a analysis result well after the fact that we are all familiar with here, simply because of uneven technical development beset by the usual bureaucratic issues the Nazi organisational structure suffered from. The Ju 288 was never going to be anything more than a troubled also-ran because of this.
The 'extended' fuselage was the original design (on paper) before Messerschmitt himself modified it, the short version was the modified one. I'm getting that from Robert Forscyth's book on Me210/410 units. The shortened fuselage (and other modifications) were to reduce weight and increase performance of the blueprint design, which the actual designer, Robert Lusser, vigorously protested and ultimately led to his resignation and move to Heinkel. Of course the V1 prototype then immediately showed problems and the test pilot said they should lengthen the fuselage to solve them, which Messerschmitt opposed due to the major investment in production machinery, as Udet had ordered it off of the blueprint. Apparently the RLM also had certain wing modifications ordered as well to simplify the design, but which compromised its stability. The ultimate fix was to return to Lusser's original design, but now with the DB605s as they had become available in the interim.The Hungarians didn't produce the Me 210 "original design".
They produced the design with the extended fuselage and they also used DB 605 engines instead of the DB 601Fs.
The reason the airframe grew in weight was modifications Milch ordered to sabotage the project by delay.Part of the problem with the Jumo 222 engine was that the requirements changed, how much was due to politics and how much was due the aircraft (like the Ju 288) getting much heavier as development went on is subject to question. as the aircraft got heavier the 2000hp version was just not going to be able to provide the desired performance.
Because the engines weren't ready.The 6 Ju 288 prototypes that flew all had mock-ups of the remote power turrets, and that was through most of 1942. Not even experimental or prototype guns mounts, just mock ups.
Which version of it? I don't think the original design was. Plus max speed was 388mph, not 400. For the original.The JU 288 was about the size and weight of Martin B-26 or North American B-28. The fuselage was much skinner but expecting 400mph performance from such an aircraft using a pair of 2000hp for take-off engines is a bit much. The Early Jumo 222s used single stage two speed superchargers. The XB-28 used turbo charged R-2800s.
Not really if there were several prototype versions of the engine plus pre-production models. Don't forget too that the Jumo 222 was supposed to be used on a bunch of prototype aircraft as well, so they probably made many test versions for those.Sorry guys, I was in a hurry for the earlier post. There were six JU 288 prototypes with Jumo 222 engines, out of 22/23 prototypes built.
Something that has never been resolved for me is that out of the 280 something Jumo 222s built perhaps 10 airframes (all twins) actually flew with them.
That is a crap load of engines sitting in warehouses (or railroad cars) for the Germans to have not used if the engines were really flight worthy.
Just about all aircraft from every country grew in weight from initial paper design to pre production or production flying aircraft, some grew a little, some grew a lot.The reason the airframe grew in weight was modifications Milch ordered to sabotage the project by delay.
The First 4 planes used BMW 801s, the 5th & 6th used Jumo 222s, the 7th used BMW 801s, the 8th and 9th used Jumo 222. What the engines had to do with getting the remote gun stations to work I don't know. One would think that at some point they would want to try the gun stations in an air frame even if the speed and climb of the air frame was not up to full specification.Because the engines weren't ready.
Estimated speeds are all over the place. Book I am using is Junkers Ju 288/388/488 by Karl-Heinz Regnat. It is Black Cross volume 2.Which version of it? I don't think the original design was. Plus max speed was 388mph, not 400. For the original.
I doubt that P & W built over 250 test R-2800s, R-2000, R-2180s and R-4360s put together for all the planes that were powered by these engines. Engines used in a test installation are pretty much standard engines, you are trying to figure out details of mounting/installation. not trying to get the engine to run or stay together.Not really if there were several prototype versions of the engine plus pre-production models. Don't forget too that the Jumo 222 was supposed to be used on a bunch of prototype aircraft as well, so they probably made many test versions for those.
AFAIK the undercarriage issue was a function of the increased weight resulting from Milch's spec changes to delay the project. The crashes were a function of the problem of increased weight and either underpowered or overweight different engines. Again sabotage through spec change.
It was delayed by about a year and when it was ready Milch changed the spec to accommodate the increased airframe weight that he also ordered. So to meet the new spec the design team had to make substantial changes to the engine, which of course set back development.
Huh? The reason the bore was changed was due to the increased power Milch's new spec demanded. The later E/F engines relied on a new supercharger and aftercooler to hit spec, not increased displacement like the failed other attempts in the C/D series. From what I can find the original A/B worked just fine with the original spec by the time Milch raised the power output spec.
Agree to disagree given that your interpretations don't fit the facts.
How much was Milch playing politics and how much was he trying to get a plane that would actually come close to the original requirements of mid 1939?
The Performance estimates seem to way off compared to what any other nation/company was able to achieve in WW II.
What if Erhard Milch didn't change the requirements for the design, both the engine and air frame, and authorizes whatever resources needed to get the engine in production so that it is able to actually enter service with the original spec in the 2nd half of 1942? This would be the Ju288A, so would avoid the problems with the landing gear and back-breaking issue that resulted from Milch's modifications of the air frame to allow for more crew and defensive armament as well as different engines.
How would it perform in combat?
Would something like this allow for (you don't pull off something like in 1943 given that the range and payload would make it viable to launch it without having to wait for major air bases to be constructed deep in the USSR at Dno?
I appreciate the engagement with the original question.Going back to the original question and assuming the Ju 222 worked as advertised (or close) we have several problems facing the Ju 288 as an operational aircraft, especially for deep penetration missions.
One specification table for the JU 288A gives a max speed of 401mph but no account of test result or estimate. However more important is the cruise speed is listed as 565kph (351mph)
at 6000 meters (19,685 ft). this is quite good but is it good enough for DAY bomber? We also don't know if that is max cruise or range cruise. We know what was originally asked for but we don't know if they got it (The Martin B-26 didn't come close to the asked for range).
The Soviet air defense system was completely different from the British or German one; the Soviet system was a point defense system because the country was simply too large to have an integrated national defense system. Plus then Soviet aircraft were largely intended for operations under 15,000 feet, so a bomber operating at 6km is going to be virtually untouchable to a point defense system with lower altitude interceptors. Later in the war of course the Soviets got Wallied aircraft that could reach the necessary altitudes, but not at the cruise speed of the Ju288 given the point defense nature of their air defense system. So they have to rely on their big AAA guns in the 105mm range to really have a good chance to hit them. So yeah the extra hour of operation shouldn't matter on the Eastern Front once at altitude.For deep penetrations into Russia flights may be 2-3 (or more) hours each way and not 1 1/2 to two hours each way (over German territory, not counting the channel) ) that the Mosquitos faced. Granted the Soviet air defense system was not as good as the British or German but if the defense has an extra hour on each leg of the flight to figure out what is going on?
The Ju 288 had fairly poor field performance, at least for a German bomber. Landing speed is given as 180kph (112mph) and take off run is 1050 meters while landing run is 1000meters. No mention of if this is to 50 ft or not (Or Luftwaffe equivalent) but doubtful given the performance of allied high wing load bombers.
No mention is given of runway type but assuming the worst, soft dirt/grass this is about what a B-26B did at 38,000lbs. Interesting is that the B-26 chart has section for landing on wet, slippery runway. Even at 26,000lbs the chart wanted 5540ft for landing roll for a 125mph approach (not necessarily landing speed) and 7070ft from a 50 ft barrier. Dry sod cut that 3330ft from 50 ft at the same weight/speed.
I don't think they had to slow down given the Lotfernrohr D of the 1943 period was able to handle speeds up to 400mph and was no worse and potentially better than the Norden bombsight (definitely less complicated).Bombing technique and bomb load need a bit of looking at. The Ju 288 could carry eight 250kg bombs which is going to work about as well as American bombers using 500lb bombs from the same height (don't know if the Ju 288 has to slow down for accuracy) but heavier bombs require sacrifice. Bomb bay would only hold three 500kg or 1000kg SD bombs.
Using mine bombs (the SC series) the plane could hold three 500kg bombs or two 1000kg bombs. Dropping two or three bombs per plane from around 20,000ft at over 300mph doesn't promise very good accuracy.
The Ju 288 was supposed to be able to dive bomb, or at least dive at a 45-60 degree angle for better accuracy? But that puts the plane closer to the AA guns and/or at lower altitude while climbing back out for fighters to bounce.
Now for the numbersPros:
- Great for high altitude bombing as its large blast radius means you can still destroy the target even if you miss.
- Great for air battles as it will destroy most bases with only one bomb without the need of a second pass or the risk of some bombs not hitting the target.
You do know the Mosquito was able to drop a small payload from over 20,000 at cruise speed accurately, right? Their bombsights and bombs were no better than the German ones. I hadn't heard that the Ju288 was supposed to dive bomb, where do you read that? Yeah diving in that would be a mistake. It does look like shallow glides were desired though as it is useful to increase speeds to get away from enemy fighters or allow a more rapid approach to a target with a constant altitude change to throw off AAA.
Bomb characteristics Mass 1,832 kg Explosive mass 1,000 kg Explosive type Amatol TNT equivalent 1,000 kg Destruction radius 34 m Fragment dispersion radius 229 m
Didn't seem to be a problem when bombing Gorky from 1941-43:The beam navigation systems don't work at long range which limits night attacks. You could fly at night but accuracy is going to be pretty dismal.
Actually one of the designers did. If you can read German there is the relevant section linked in this post:However well the Ju 222 engine did or didn't work at the 2000hp rating nobody has claimed it was good for more than 100 hours even on the test planes.
They were able to do 100 hour continuous bench tests without issue. 4-6 hours per mission with service in between would likely be less wear on the engines. 17-18 missions per overhaul isn't really that bad for a medium bomber with a long range, heavier payload responsibility. For a tactical bomber that could be a problem though. The Pe-8 was an entirely different bomber with a host of issue that would make the He177 look reliable.US and British engines could reach 300 hours or more in bomber service. (that is max, not average). If you are planning 6 hour flights with 100 hour engines you get 17-18 missions at best before engine change. Better figure a lot less (US and British often had to change one or more engines well before the max life). This was a major problem with the Russian PE-8. yes they flew some long range missions with them but not many, just enough to keep the Germans on their toes. These slower bombers had some engines that wouldn't make 50 hours and had to be changed after 5-6 missions (if they made it that long.) They lost aircraft due to engine failure, so did the US and British. This is a big problem with heavy twin engine aircraft. A four engine plane, if it looses and one engine on each side is in better shape at 1/2 power than a twin that looses one engine. An over powered twin is a bit different.
Of course, but how common of a problem was that? Even with existing German twin engine bombers.Being even 600km inside soviet territory if an engine quits on the Ju 288 is not good.
Given the enormous impact a successful Eisenhammer (actually Aktion Russland was the full name of the operation I found out, Eisenhammer was portion of it) the cost would be WELL worth the expense. Plus the Jumo 222 had the best specific fuel consumption and power to weight ratio of any German aero-engine of the war. If it meant they could scrap the He177s by 1943 that would be a vast savings of resources compared to OTL. If you want to talk about a waster of resources, how about building 1200 He177s with all the crew, fuel, etc. investments that went into that! As it was the Germans did create the 6th air fleet to do just this in Russia from 1943 on.The logistic impact of the Ju 288 might be more effort than it is worth. The cost in engines, fuel, and training for special missions (you don't pull off something like Operation Eisenhammer with normal line squadrons) might have been better applied to targets closer to the front.
You can check the link yourself for the list of the extensive damage and resulting massive resource investment the USSR made to deal with the damage and protect the city better. The Soviet shoot down claims are suspect though.Two-engine bombers of the squadrons KG 27 and KG 55 participated in the raids, which rose from the airfields near Orel and Bryansk and, bypassing the Moscow air defense zone, they flew up to Gorky from Dzerzhinsk, Bogorodsk and Arzamas. To use the darkest time of the day, bombardments were conducted from 12 am to 2 am. At first the target was designated as light missiles and air defense was blocked, then bombed from different heights and directions. Tactics changed every time. High-explosive, fragmentation and incendiary bombs of various calibers (up to 2000 kg) and incendiary liquids were dropped into the city. The results of each raid recorded by reconnaissance aircraft flying over the city at an altitude of 7 km, at 5 pm the next day.
This should answer the above uncertainty:
Where does it say that? In the webpage they show only 3 crew members and the cockpit is smaller than the 4 man version.This is an interesting diagram and illustrates the type at the production standard as the Ju 288B fitted with Jumo 222s, with power at 2000 ps. This is the production version with four crew and extended wings etc.
The second chart in that post is different than the first. The first says 2000hpm the second 2500. Post combined the A and B series of the Ju288.The difference starts to show when you look at this previous document that illustrates a prototype aircraft and its estimations of performance at the bottom of John's post in the image thread of this forum:
Two different charts with different performance. Struggled before the 4 crew change? You're confusing things here, the 4 crew member change came before the increase to 2500 hp to match the weight increase. Stop mixing things up, you're seemingly doing so just to muddle the conversation. I'll get to your other posts in time, how about you stop commenting until I do so I can debunk your bullshit?It puts the performance of the Jumo 222 at 2500ps, now the engine in reality struggled to reach that power output even before the changes were made to the airframe (going from three to four crew makes operational sense; the Ju 88 had four crew, three was surely not enough), and let's face it, the first examples were prototypes, in prototype operational requirements are worked out and implemented into production aircraft suitable for the armed forces use. This is no different in the Ju 288 and the first A models were simply not ready for production. The age of building the first prototype as the production standard did not become a thing until after WW2.
Alright, you're obviously trying to derail the thread. Stop being a douche.It is worth stating however that the figures produced throughout the lifespan of the Bomber B programme and the Ju 288 programme were largely estimated only, so let's not fall into that dreamy-eyed state of accepting them as gospel, simply because they are German.