testing captured Allied aircraft of WW2

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Joe Broady

Airman 1st Class
105
155
May 30, 2019
A few months ago I promised to post a some opinions from "Luftwaffe Test Pilot: Flying Captured Allied Aircraft of World War 2" by Hans-Werner Lerche (1977, English translation 1980). Despite leaving the book in plain sight for motivation, I'm just now getting to that.

From childhood Lerche (b. 1914) was interested in mechanical things. This turned in the direction of aviation. Step by step he went from building flyable glider models to flying full sized gliders. This was difficult, as the family was not well off. Mr. Lerche died in 1919 and the family had to relocate to Breslau when Posen became Polish after the war. Mrs. Lerche worked as a librarian and also had her husband's pension, but the postwar inflation eroded much of its value. She had a hard time supporting herself and four children.

Flying got easier after Hitler came to power. By that time Lerche was already a licensed glider pilot and instructor. "One had already noticed how during that year since Hitler had come to power money was much more readily available, and everyone who wanted to fly could do so without even an hour's work beforhand in workshops; in addition to that in 1935 we were given a large number of new gliders."

Later I'll include more biographical information, but now let's go to the first aircraft in the book. The flight occurred in August 1944. I don't think he gives the exact date. All these excerpts will be so heavily trimmed that I'll omit ellipses (...), as the great number would be annoying. And in many cases I have had to re-arrange the text so it makes sense despite the omitted material.

"This Avro Lancaster had fallen into our hands in slightly damaged condition a few weeks previously. I was very impressed by this big aircraft with its fuselage nose rising some twenty feet off the ground. I intended to ferry the Lancaster direct to Rechlin, without a trial flight, taking only my flight engineer. My reasoning was simple: a small thing like a puncture was able to render this captured bomber, to us a unique specimen, unable to fly for quite some time, and each unnecessary take-off would naturally aggravate the hazard.

"I derived some comfort from the fact that the Lancaster had been reconstructed in the Travemünde Lufthansa workshops where people had most extensive experience with larger aircraft. For the same reason I could also be confident that the correct high octane fuel and high grade engine and hydraulic oils had been put into the tanks. If the red limit marks on the instruments were correct, the Rolls-Royce Merlin engines tolerated fairly high oil and coolant temperatures.

"The engines were running smoothly, as only Rolls-Royce engines can run. The power to fly was there, now for the rest of it. During taxiing the visibility was good. I made mental note of the line of sight from the cockpit over the fuselage nose to the horizon in tail-down position — this was of especial importance if the pilot did not know the landing speed.

"Having tested the four engines I opened the throttles carefully, bucause I could not help feeling that the big bomber had a tendency to swing to port. The empty aircraft accelerated quickly, its total weight now being hardly more than 22,000 kg (48,500 lb). However, to raise the tail I had to push the control column vigorously. Then I pulled the Lancaster to a slightly higher angle of attack at which it had to become airborne if the speed was right. It was, indeed, kind enough to do me the favour. Immediately I throttled back to conserve the valuable engines, braked the wheels with the pneumatic lever at the control half-wheel, and then told my flight engineer to raise the undercarriage.

"At about 8000 feet I evaluated the stalling characteristics with both open and closed throttles and with flaps and underarriage locked in up and down positions. During each operation I noted the figures on the airspeed indicator, because despite the absence of any ground effect these readings gave me certain clues as to the behaviour on landing.

"As I was throttling back, all of a sudden a horn began to sound and gave me a start. I already knew of this blessed device reminding the pilot to lower his undercarriage before landing from other British aircraft, such as the Spitfire, Blenheim and Wellington. Nevertheless, it will make you jump all the same if an aircraft suddenly starts giving off such unusual sounds — the more so as you are hardly used to pleasant surprises as a test pilot.

"I tested the flying characteristics of the Lancaster more or less as a routine matter — for my own 'domestic use', so to speak. One could hardly expect any bad characteristics in an aircraft used in such great numbers for night operations.

"The flying characteristics and performance of the Lancaster were really of secondary interest to us at that time. This sole example of the British night bomber captured in flying condition was of interest largely because of the difficulties it caused our air defences when dropping aluminium foil strips to jam or mislead ground or airborne radar. In an effort to solve this problem the Lancaster was to be probed at night by German aircraft equipped with new elecronic AI devices operating from the Werneuchen airfield near Berlin.

"Any flights to Berlin, particularly with a suspicious 'bird' like this, had to be duly announced and of course one had to be ready at any moment to fire the currently required identification flares: the yellow-painted engine nacelles and wing tips and the German crosses alone were no life insurance.

"Every night flight, even without unforseen events, is an exciting affair when you are hanging between heaven and earth with only a flight engineer and radio operator for company. Under these circumstances the strange aircraft with its still unfamiliar instruments offered no reassurance to me. For one thing, the very basic blind flying devices indicated completely differently, making this particular night flight even more difficult. Such deviations naturally required the utmost attention on the part of the pilot. In addition to that the conversion of the indicated data, such as miles into kilometres and feet into metres, was also tedious and time-consuming work.

"We had already finished our work with the second monitoring airclaft at an altitude of 13,000 ft and were waiting for the next to arrive. But what was this? Instead of announcing the third machine, my radio operator reached for the screwdriver! There was a fault in his radio set, and so I was left to take care of the navigation myself. [German radios had been installed for this test.]

"One thing was certain, though: I had to get clear of the 'colleagues from the other side' who would soon be approaching from the west as quickly as I could. Perhaps, while veering off to the east, I could even catch sight of an illuminated town with an airfield.

"We were flying at an altitude of about 1300 ft across the landscape. I had the navigation lights on to show from afar that we had no evil intentions. Soon afterwards, a flashing light appeared to the left in front of us, and where there is a flashing light there must be something else. To be on the safe side, I began to fly in circles. What was more alarming, however, was that anybody who knew anything about aeroplanes could hear at once that we had a foreign aircraft. For that reason I lowered the undercarriage, switched on the landing light and let down the landing flaps a little as well. I had heard once that this was the way deserters would ask for 'nice weather' — which for the time being seemed more important than the use of identification flares.

"There was nothing to be seen for a while, but then suddenly airfield lights came on below us. I flew a wide turn before approaching for landing and then, with nearly full throttles and just a little more than the minimum speed I hopped across the airfield boundary and touched down directly behind it. Immediately I pushed the pneumatic brake levers mounted on the control column vigorously as long as the remaining relative wind pressed down the elevator at the tail and helped to prevent a nose-over. Gererally speakig, I did not like the unusual pneumatic brakes as much as our hydraulic brakes which, in my opinion, could be operated more precisely. But any brakes were a boon in this situation!

"As we climbed down, some figures approached us in the darkness. But we did not receive the hearty welcome we had expected: two soldiers stopped at a respectable distance and pointed their submachine guns at us. Naturally, nobody believed that we were Germans: a Lancaster was a Lancaster, and that was British! Not even my suggestion to telephone the Rechlin and Werneuchen airfields to confirm our identities was readily accepted. Then, in the middle of our negotiations a third man came over from the airfield flying control office flourishing a white piece of paper. It was a teleprinter message that had just come in. This changed the situation like magic. It transpired that Flugkapitän H. who had been flying the third of our monitoring aircraft, had returned to Werneuchen immediately after he had become aware that our radio had failed and sent this radio message 'To All'.

"The airfield was operated by a flying training school for single engined aircraft and was never used by heavy multi-engined machines. To me it was particularly gratifying that this night landing with a strange four-engined aircraft under such difficult circumstances had gone so smoothly on this small airfield."

To be continued.
 
More from "Luftwaffe Test Pilot: Flying Captured Allied Aircraft of World War 2" by Hans-Werner Lerche, 1977 (English translation 1980). As before, the material has been heavily edited to squeeze a chapter into a few paragraphs.

"One day in October 1943 I received a call that an intact Boeing B-17 had made a forced landing near Esbjerg in Denmark. I believe it was the first B-17G to fall into our hands. The reason for this forced landing was that the propeller pitch change had failed on one engine, leaving it set in take-off position. As a result, the aircraft had rapidly lost speed and had to leave its formation.

[In the book is a photo of a B-17 in German markings and clearly visible tail number 124585. The caption says, "Boeing B-17F 41-24585 DL + XC". Also, Appendix 1, "Aircraft types flown by the author (with known identity markings)" lists "Boeing B-17F & G Flying Fortress DL+XC"]

"We found the big American bomber standing in a clearing, surrounded by tall trees. Fortunately the soft ground had shortened the landing run so much that no damage had been done. I estimated that the trees began only some 2500 ft away and to get the big aeroplane airborne it had to be lightened as much as possible.

"The next morning everything went well. I tried a few taxiing runs with the big bomber, and did not get the impression that its wheels sank in too deeply. It was encouraging that this was not my first flight in a B-17. I was able to become airborne just beyond the half-way mark, and pushed the control wheel forward again to remain barely above the ground to gain enough speed to pull the B-17 away over the tops of the first trees.

"During such critical take-offs the question arises of whether it is worth risking a few small tricks when every single metre matters. For example, things like lowering the landing flaps shortly after attaining the unstick speed, or raising the undercarriage at the first hop off the ground. I don't think much of such niceties when every metre is at stake. The rapid retraction of the undercarriage alone is a case in point: one must be completely in the picture as to what exactly happens when it is retracted. For example, if the main wheels have so-called partial (or hinged) covers which have to open before retracting, this may not only increase the drag as the undercarriage begins to move, but impair the lift as well.

"The B-17 interested us not so much because of its flying characteristics but more because of its supercharged engines, which gave excellent performance at higher altitudes. These superchargers were activated by exhaust-driven turbines which became really efficient corresponding to the greater difference in air pressure at higher altitudes, exactly when more power was needed. For that reason the Flying Fortress was primarily made available to the power plant experts, who tried to get to the bottom of as many details of its engines as possible. The most varied measuring instruments were installed for this purpose, so that the fuselage behind the bomb-bay was like a laboratory with engineers in attendance.

"The following test flight was to take place with the full complement of engineers aboard. Our task was to monitor the engine and airframe performance in climbing to higher altitudes. We had reached an altitude of at least 9000 ft when suddenly we saw ourselves in a nice mess: the starboard outer (No. 4) engine was on fire! Now, what does one do when an engine is on fire? By no means throttle back the misbehaving engine, but instead stop the fuel flow immediately by shutting the relevant fuel valve so that the fuel already in the pipes and carburettor is used up as quickly as possible. That done, I alerted the rest of the crew. For this purpose there was a loud alarm bell in the B-17, which could be heard everywhere despite the rumble of the engines.

"The fuel in the pipes was soon used up, but the flames hardly became smaller at all. We were still flying at about 10,000 ft and despite the considerable all-up weight, the aircraft was quite easy to hold at this height on only three engines. By this time the crew were standing at the bomb-bay doors, ready to bale out. I was standing between the two pilot's seats with both hands on the control wheel. The fire was still on. We were well aware of a bad counterpart in the shape of our Heinkel He 177, whose wing would break off fairly quickly in the case of an engine fire.

"Finally, after three or four minutes of stand-up piloting the flames began to decrease but it took about six minutes before the fire went out. But I was still left with the task of landing the strange heavy aircraft on only three engines. There was no emergency fuel release and I also had to take into account the fact that with only three engines it would be impossible to go around. In any case, the day was already too far advanced to fly around and consume the fuel.

"I recalled the time when I had to land a machine [Do 17] with one 'dead' engine. We had just passed an airfield. However, in my excitement I had failed to notice that it was the smaller Jüterbog-Damm airfield used by a primary flying training school, not the larger Jüterbog field! The approach with the undercarrriage down happened rather high and not being able to go around again I had no alternative but to perform a so-called 'Giant Californian side-slip'. Despite the small field the landing worked out very well indeed.

"Such emergency situations give an enormous amount of experience. Why shouldn't the landing of the overloaded B-17 at Rechlin be just as successful? And it did work! The subsequent examination revealed that an exhaust pipe had become loose so that the hot exhaust gases had blown directly onto the fuel pipes, which inevitably caught fire.

"Another, but more pleasant memory concerns a round flight with the B-17 demonstrating the Flying Fortress to our fighter pilots, where they had the opportunity to try out mock attacks. It was May, 1944. At that time, attacking the B-17 from ahead was considered a particularly effective tactic. However, during the preliminary discussions I had already pointed out that the B-17 had a rather tall fin. Be that as it may, I must say that the fighters dealt pretty hard with the 'enemy' aferwards, and sometimes my fingers itched to make a timely evasive manoeuvre. To be sure, the fact tht I was flying a 'friendly' B-17 must have had something to do with their wild attacks. I was relieved to land with an undamaged tail unit after all.

"Meanwhile, the word had got around that a B-17 was standing at Munich-Riem airfield and this attracted not only the fighter pilots but also other military personnel. So much so in fact that even generals were queueing up to have a look! Further flights followed and one can imagine that it must have been an exalting feeling for the fighter pilots to fly so close to a Flying Fortress without being shot at 'out of all buttonholes'.

"What was really outstanding about the B-17 which made it, together with the Liberator, the standard day heavy bomber in the European theatre of war? It certainly was not fast in low altitudes; only the exhaust-driven turbo-superchargers gave the B-17 its good performance at higher altitudes. All in all, that was for me the most admirable thing about American planning, namely the consequential pursuit of a concept once it had been recognised as correct, in this case the effectiveness of raids carried out by well-armed high-altitude bombers flying in close formations. One must remember that several years would pass between planning and execution of a concept. Possibly only the idea of keeping the attacking fighters at bay with heavily-armed bombers flying in close formation and firing from all 'portholes' had to be revised. The correct solution to this problem was escort fighters — and several versions of these, with excellent performance, were soon available.

"Nor did the rather poorly adjusted control forces on the American bombers have much detrimental effect, as this was certainly not decisive during the appooach at great height, and even less so after the bombers had been equipped with an excellent three-dimensional autopilot.

"It must be stressed that the respectable speed of the B-17 at higher altitudes was due solely to its excellent exhaust-driven turbo-superchargers. But for the production of these devices one required not only the know-how but also large quantities of heat-resisting materials which we were lacking in Germany.

"I clocked 35 hours on the B-17. I really enjoted flying the 'Fort' as it made a most reliable impression, and the engines always performed perfectly, except the one engine fire which was probably due to maintenance difficulties. It did have its drawbacks: for example, the forces acting on the ailerons were relatively high, and the rudder felt as if it were set in concrete. But it was much more important that the aircraft was easy to fly and land. When one had become accustomed to the higher all-up weight and the strange instruments, it could be compared with our He 111 in the degree of effort needed to fly it."

The Martin B-26 Marauder will be the subject of my next installment. (I am following the same sequence as the book.) The evil reputation of this airplane was well known to the Germans, and in fact Lerche's first flight was nearly fatal.
 
Where's the American crew? Surely they're told to destroy their aircraft rather than to deliver it in flyable condition?
 
Where's the American crew? Surely they're told to destroy their aircraft rather than to deliver it in flyable condition?
I found this on warhistoryonline

B17f-42-30336 landed in a field at Norholm Estate near Varde Denmark on 9.10.1943 after developing engine trouble, the crew baled out and the pilot landed the plane. The Germans captured the plane and later test pilot Hans-Werner Lerche flew the plane out of the field to Esbjerg Airfield. It was then flown on to Rechlin for evaluation, it was given the code 7+8 and is known to have been flown until Dec 1944. [Via]
 
Boeing B-17 Flying Fortress

2-30336 (385th BG, 548th BS, *Miss Nonalee II*) attempted to reach Sweden with mechanical problems Oct 9, 1943, but came down at Norholm Mark, near Varde, Denmark. 1 evaded, 10 POW. Repaired by Luftwaffe and flown as 7+8 MACR 824. "Miss Nonalee II" was assigned to KG 200 but crashed near Bad Voeslau at the transfer flight to Vienna on 28 August 1944. It was salvaged and transported to Wiener Neustadt for repair which wasn't finished before Russian troops arrived in March/April 1945. The aircraft wore still the Rechlin markings 7+8 at the transfer flight

sources: Joe Baugher's Home Page , Luftwaffe im Focus nr 25


 
Interesting how the two sources compliment each other. The earlier question, "why didn't the crew destroy the plane?" seems to be due to only the pilot being on the plane when it landed.
 
Another excerpt from "Luftwaffe Test Pilot: Flying Captured Allied Aircraft of World War 2" by Hans-Werner Lerche.

"A particularly interesting period of my evaluation flying career now began. There was hardly an aircraft type I had not flown. Perhaps the difference from my earlier days at Rechlin is best characterised by the fact that I no longer had to ask whether I might be allowed to fly a new aircraft type. The types I had flown during May, 1943, made quite an interesting collection. Beginning with a Messerschmitt Bf 109G fighter, I then followed with overload take-off tests with a Ju 52/3m. Then came flights in its successor, the Ju 252, with its smooth metal skinning and retractable undercarriage — quite a difference from the old 'Auntie Ju'; then a cross-country flight in a Bf 108 Taifun; measuring flights in a Henschel Hs 129 single-seat anti-tank aircraft towing a DFS 230 cargo glider; flights in the Fi 256, the four-seat successor to the well-known Fi 152 Storch; and cross-country flights in the giant Me 323. In May I also added the He 219 night fighter to my list.

"Meanwhile, there was again something on the agenda, a captured Martin Marauder. A mid-wing monoplane with an aerodynamically faultless fuselage, the aircraft had a fast and racy look about it even from the outside. But the B-26 also had its negative points. With its small wing area and a gross weight of some 30,000 lb (later increased to over 38,000 lb), the load per square foot of the wing area was relatively high, and the high take-off and landing speeds caused so many bad accidents that this aircraft at first had a poor reputation amongst the crews and was known as the 'Widow Maker'. Its other nickname of the 'Flying Prostitute' was unknown to me when I became intimate with the Marauder for the first time. Apart from other bad characteristics, malicious tongues also asserted that the Marauder's landing speed was higher than its cruising speed. That much was known to us — and it was to be expected that the small grass field at Rechlin would not be abundant enough for this 'hot' aircraft.

"Our share of excitement with the Marauder was still to come. Perhaps the adjustment of the propellers was not set correctly, or perhaps someone had already tinkered about with them. But what I experienced on my first take-off in the strange aircraft surpassed all expectations! Of course before the start the engines were carefully and briefly run up and then switched off again, and the speed governors tested. Then the usual procedure: full on the brakes, full throttle, and then brakes off and away! At first the engines ran perfectly and the aircraft accelerated well, pushing my back into the seat.

"It may have been that the automatic propeller regulator did not function properly, letting the engines overspeed before reducing the revs, and then unevenly. All at once the starboard engine began losing power and the Marauder showed a strong tendency to swing despite the nosewheel undercarriage. By that time it was already too late for me to cut the throttle as the aircraft was going too fast to stop, but on the other hand not fast enough to become airborne. Nevertheless, although the engines were running with far too few revs I managed to lift the Marauder just off the ground shortly before reaching the airfield boundary.

"As soon as I could feel that the aircraft was actually flying and had not just been 'hauled up', I ordered the flight engineer to raise the undercarriage since I wanted to avoid the risk of touching the ground with the wheels down. In this manner we floated past the radio station on the right at a height of some 3-6 feet. Since there was no immediate danger for our aircraft in the shape of trees or other obstacles, I thought it would be better to stay close to the ground and wait to see whether the engines would pick up enough revs to allow us to climb, or whether I had to cut the throttles and risk a crash landing.

"But for my colleagues observing this take-off from the other side of the field everything looked much more hair-raising. They had heard the brief overspeeding of the engines, the subsequent regulation of revs, and the irregularities in the engine running, and then seen the Marauder speeding towards the Schropp'schen mountain just skimming the ground. In addition to that the B-26 raised a cloud of dust as it raced low over tilled land, like the lift turbulence produced in a wind tunnel, until the spectators could no longer see the aircraft. As a result, quite used to untoward happenings at Rechlin, they awaited the seemingly inevitable crash and subsequent blast of flames and mushrooming smoke.

"However, the propeller speed control gradualy began to function smoothly and I succeeded in commencing a climb after raising the landing flaps. Perhaps the lubricating oil had been too thick and prevented correct regulation of the propellers. Be that as it may, I am sure that my decision to stay close to the gound at low speed had been correct; it was also best in the case of a possible crash landing.

"After the engines, or rather their propeller adjustment, had been reminded of their duty, I got to know the B-26 as a quite passable aircraft. But it was a piece of equipment that had to be handled with great sensitivity. On a longer flight, I then became good friends with the Marauder and the propeller pitch control now functioned properly. This was one of the typical instances when a report on faults could ony be prepared when everything had gone well in the end. If the take-off had gone completely wrong, no-one would have known that the cause was nothing more serious than the hydraulic oil which had probably become too thick."

To be continued.
 

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