Editorial Note: Phillip Andrews, editor of Air News recently returned from a five months' tour with the USAAF Air Transport Command, follows his detailed summary of the Mediterranean Allied Air Forces campaign with an analysis of German aircraft developments in the last months of the war. Information contained in this article is based on interviews with former Luftwaffe personnel and examination of abandoned enemy equipment. Written last July, publication has been delayed for reasons of security and the original report augmented, corrected or confirmed by findings of the Air Technical Service Command, Wright Field, to whom the editors are also indebted for many of the illustrations which appear on the following pages.
USSTAF Press Camp, Munich, Germany (Delayed) Whether the German conception of air power was ahead of, or behind its time is difficult to say. The most plausible answer is that it was both.
The high command, or whoever else was responsible (and all fingers now point to Hitler), failed to comprehend either the negative or positive virtues of strategic bombardment. Hitler not only disdained the use of this new weapon but believed implicitly that it could not be used against him.
Hitler was an amateur. His technicians were not. They went about their business with traditional skill, precision and considerable foresight. Hampered by inadequate production facilities, limited labor resources, inferior materials, erratic transportation, official stupidity, and bureaucratic interference, they proceeded to develop an air force, elements of which compare most favorably with the best that Allied engineers could produce under infinitely more favorable circumstances.
German jet- and rocket-propelled aircraft in particular constituted a potential challenge to the Allied plan of aerial interdiction. A turbine-powered He-178 had flown in the week before war began in 1939. That Germany had no jet planes for the Battle of Britain a year later was less the fault of German engineers than of Hitler's myopic arrogance.
But even he, when presented with plans for the Me-262, could hardly fail to recognize its merit. By this time, however, Hitler was so incensed, so intent on personal revenge that he would approve production only if it were fitted as a bomber for use against England. When Goering replied that the removal of its four nose guns would so alter the center of gravity as to make the plane unflyable, Hitler suggested that the balance be maintained by installing fuel tanks in their place. "Hitler, in his ignorance," says Goering, "did not realize that, since this extra fuel would be consumed in flight, the original unbalance would return. In your aerial warfare, you had a great ally in the Fuehrer."
The comparative simplicity of airframes and power units made the jets easy to produce and minimized the effect of Allied strategic bombing. The Me-262 is much less complicated in construction than a comparable twin-engine aircraft of conventional design and so can be manufactured with a relatively small complement of skilled personnel.
In one subterranean factory, virtually invulnerable from the air, hundreds of V-2s were found in various stages of completion and stockpiles of parts compared with those of any large American aircraft factory. The tunnels were cold and damp, the light was poor, and the atmosphere reminiscent of a New York subway. Several hundred yards up the hill, the labor housing problem was perfunctorily solved by a concentration camp. Throughout the Reich there were a number of such factories. Had they been utilized for the production of jet aircraft rather than for retaliatory rockets and "buzz-bombs," such crises as the Battle of the Bulge might have been concluded much differently.
In addition to the Me-262, Germany had developed several unconventional designs which showed considerable promise. One of these, the Do-335, was finally put into production late in 1944, although it had been made available to the Luftwaffe at the beginning of the war. Distinguished by twin engines arranged in tandem, it was capable of extremely high speeds and, although subsequent examination has revealed some undesirable characteristics, these might well have been remedied through production and operational experience.
One of the fastest planes ever to appear over Europe, although extremely short on endurance, was the Me-163 "Alarm Fighter." Rocket-propelled, it has a vertical fin, no elevators. Originally reported as a flying wing, it too was based on a prewar design. Its phenomenal rate of climb and remarkably high speed, utilized earlier in the war, might have made conventional British and American escort fighters obsolete. That it did appear on infrequent occasions is confirmed by reports of Allied airmen and by the apocryphal German tale that one Me-163 in two takeoffs and two landings shot down two aircraft, all in the short space of seven minutes.
As there is no reported instance of combat between German and British jets (the use of the latter was largely restricted to the interception of V-1s and, although at least one Lockheed P-80 appeared briefly in Europe, it was not used in combat), it is difficult to make any conjecture as to what the results would have been of a more concerted jet production program.
Certainly no moderate increase would have prevailed. The numerical superiority of Allied lighters was overwhelming and their tactics infinitely superior. Outnumbered German jet pilots were in constant danger of being "boxed in" and frequently while jockeying for position would run out of fuel. German pilots have expressed amazement at the range of American fighters and complained that their jets were misused by being started too early and often in the wrong direction.
Plane for plane, it would appear that the Luftwaffe had, or was close to having, fighter parity. The P-80 is only about 25 miles per hour faster than the Me-262,and pilots who have flown both suggest that this discrepancy could be compensated for by the elimination of certain extrusions on the German jet. German scientists were ahead at the beginning but they were gradually losing ground. In a technological race, the pool of British-American knowledge unquestionably would have won out over a country which for the past five years had been conducting its experiments in a tunnel of technical isolation.
Specifically, British and American engineers working together succeeded in exploiting the intrinsic simplicity of turbine-powered aircraft while the Germans, hampered by metallurgical deficiencies and lack of a coordinated development program, sought to solve one complexity by adding another. German-built turbines, for example, due to a shortage of lightweight heat-resisting metals, were found to be much heavier than comparable units produced by the Allies, whereas American metallurgical knowledge coupled with British experiments in jet propulsion resulted in a more powerful engine for its weight than might have been produced by the same two countries working independently of each other.
Willi Messerschmitt, who ought to know, says that his Me-163 was interesting only as an experiment. It could attain a speed, he says, of 625 miles per hour at any altitude up to its service ceiling of 50,000 feet but he admits that an operational range of not more than ten minutes limited its utility. Messerschmitt's lukewarm appraisal is qualified by Goering's statement that Professor Lippisch, designer of the plane, and Messerschmitt bickered constantly. Their personal differences retarded development of the 163 and a shortage of C Stoff (a solution of hydrazine hydrate in methanol) made it necessary to abandon production.
Like other unorthodox weapons to make. their frantic appearance in late 1944 and early 1945, the Me-163, nicknamed the Comet, was conceived prior to the war. Designed for the defense of specific targets, it could take off quickly in a short distance and climb to 30,000 feet in less than 3 minutes. Like Natter, it was powered by a Walter liquid-rocket unit which in addition to the critical C Stoff burned concentrated hydrogen peroxide, called T Stoff.
The Comet's wooden, plywood-covered wings are of special swept-back design with a marked wash-out of incidence towards the tip. The fuselage is of metal construction. "Elevons" which serve both as elevators and ailerons are located outboard in the wings; there are no horizontal tail surfaces.
First reported as a flying wing, the Comet was presumably flown with the pilot in prone position. Examination of a captured model revealed that the cockpit, although narrow, was of conventional design. Armor includes a nose cone constructed of 15-mm plate. Laminated bullet-resisting glass gives the pilot added protection from frontal attack. Two triangular plates comprise the side cockpit armor. No provision is made for defense against attack from the rear except the plane's high speed.
In general, the 163 proved more dangerous to the Luftwaffe than to Allied bomber formations. Five sorties was considered the maximum life expectancy of pilots assigned to Comet squadrons. Takeoff was made in a manner similar to that employed on the Ar-234. The undercarriage is jettisoned and landing is made on retractable skids. Fields are said to have been marked off like a football gridiron; if a given RPM was not reached according to these markings, the pilot, knowing that he was certain to crash, climbed out on the wing and opened his parachute. Takeoff casualties were high. As landings were frequently made after the 336-gallon fuel load was exhausted, pilots were given special glider training before taking on the 163. Like the Ar-234 it was equipped with a parachute tail brake and landing speeds were surprisingly slow.
Official top speed of the Comet, contrary to Messerschmitt's statement, is 550 mph at 20,000 feet and above. Armament consists of two 30-mm cannon, one in each wing root, firing a total of 120 rounds. Normal flying weight of the 163 is 9,500 pounds; wing span is just over 30', length, slightly under 20'. A slightly larger modification, designated the Me-163C, is equipped with an auxiliary cruising jet and pressurized cabin. It is faster by 40 mph, weighs 11,280 pounds and has a ceiling of 10 miles.
In August, 1944, Allied bombers were roving above the Reich in such numbers it became apparent that no ordinary means could stop them. It was then that the idea of Natter (German for Viper) was conceived and four designers, Heinkel, Junkers, Messerschmitt and Bachem, were directed to submit plans. Dr Bachem's design, was chosen and in November of that year Natter BP-20 was flown for the first time. Smaller than the Me-163 (span, 13'; length, 20'6") and. simpler to build (wooden airframe required only 600 man hours) it looks more like a mockup than a full-fledged fighter. In conception Natter was half anti-aircraft artillery, half interceptor. Because of the short takeoff area required it was well suited to close defense of vital targets and pilots required very little training. Launched from a nearly vertical ramp, powered by a Walter rocket unit similar to that used in the Me-163, the initial rate of climb was calculated at 37,000 feet per minute, its top speed at more than 600 miles per hour. A controlled missile until within a mile of its target, the pilot then takes over, jettisons the nose cone exposing 24 Fohn 73-mm rockets which are fired in one salvo. Protected by exceptionally heavy cockpit armor and presenting a small head-on target, the pilot is virtually invulnerable to enemy fire. His principal danger is in takeoff and descent. Going into a dive after two minutes or less. in the air he bails out and a section of the fuselage containing the rocket unit likewise descends by parachute. On paper the Natter is a formidable weapon. It has been reported in action on several occasions but may have been confused with the Me-163.
Best of the German jets on the basis of its operational record and one of the European theater's most formidable fighters, Allied or Axis, was the Messerschmitt 262. A single-seat, twin-jet, low-wing, all-metal monoplane, it was designed in 1938, first flown in 1940. A series of nine modifications resulted in the production model which made its first appearance against British and American bomber formations in the summer of 1944. Exceptionally fast, heavily armed and armored, with few vulnerable parts, it was more highly regarded by Allied airmen than by some Luftwaffe pilots whose confidence in the plane's high performance was tempered by erratic behavior on takeoff and landing.
Whatever its potentialities, the 262 was seldom used to best advantage and never in effective quantity. Production plans in August, 1944 called for 500 in December, 600 in January and February, 800 in March, but by war's end no more than 1,400 had been produced. Of these, half were destroyed in training accidents and by Allied attacks on German airfields. Most of the remaining 700 were either shot down or crashed due to failure of jet units. Others were destroyed by retreating Germans and only a handful remained to enlighten Allied Technical Air Intelligence squads.
Designed to accommodate Heinkel jet units, production and engineering difficulties resulted in the substitution of Jumo 004 Turbinenlauf power plants. Nearly 12' and weighing 1,540 pounds, the Jumo is heavier than comparable British units, develops a thrust of 1,605 pounds at sea level. A small reciprocating engine is used for starting.
Armament for the 262 was to have consisted of two 55-mm cannon, but these, though designed, were not yet in production. Hitler then favored the installation of 50-mm tank guns but Goering countered with a reminder that the barrels would extend six feet beyond the nose, thus impairing the plane's stability and performance. Eventually, four MK 108s (30-mm cannon) were selected as standard armament for the A-1 fighter version and two cannon of like caliber for the A-2 bomber. Synchronized to converge at between 400 and 500 yards, the guns were generally fired at about 800 yards in order to compensate for the plane's high speed. Reflector gun sights were first installed, later to be replaced by newer gyroscopic sights. Reportedly, a few Me-262s carried six guns and there is evidence of a plan to install two batteries of twelve R4M rockets under each wing. These would have been launched at Allied bomber formations at more than a mile's distance.
Armor protection consists of 16-mm head and shoulder plates and a forward cockpit bulkhead of the same thickness. Absence of armor and proximity of a fuel tank to the rear of the pilot is apparently discounted due to the plane's high speed. German pilots interrogated on this point were confident that nothing in the air could match them. With 522 gallons of fuel, 360 rounds of ammunition, the A-1 takes off at 15,550 pounds. The A-2 with its two guns, 160 rounds of ammunition, and one 500-kg or two 250-kg bombs, weighs 15,400 pounds.
Standard fuel for the Jumo jet is a brown coal oil known as J-2 and distinguished by a particularly disagreeable odor. Diesel oil and aviation gasoline may also be used but the latter is not considered practicable due to an extremely high rate of consumption.
Without bomb load or auxiliary fuel tank the Me-262 requires from 900 to 1,100 yards for takeoff on concrete and from 1,100 to 1,400 yards on a grass field. The normal required takeoff run of 1,100 yards is reduced to 650 by means of two ATO rockets having a total thrust of 1,000 kg. As few German airfields were equipped with concrete runways, Autobahns were frequently used for operations.
At full throttle, a straight and level speed of 830 kph (515 mph) can be maintained for ten or fifteen minutes. Cruising speed is approximately 465 mph and speeds of 650 mph in dives were not uncommon. Willi Messerschmitt quotes a maximum speed of 560 mph in level flight and at any altitude. That American test pilots were able to get no more than 525 mph out of the plane under favorable conditions he attributes to considerable variance in individual jet units. Messerschmitt also admits to inferior construction due to inadequate materials and lack of skilled labor. Elimination of extrusions as in the Lockheed P-80 would have added at least 25 mph to the plane's top speed. Despite reportedly weak construction and a tendency to strip at high speeds, one German pilot interviewed by Air News' correspondent claims a successful power dive at 1,200 kph (750 mph).
The Me-262's high performance is due not only to the power generated by its two big Jumo turbines but to an airframe that is fundamentally sound, aerodynamically clean. The horizontal stabilizers are situated well out of the slipstream and so there is no flutter at high speeds. Extremely thin wings minimize the factor of compressibility.
Endurance of the Me-262 ranges from 45 to 90 minutes. Stall characteristics are good, ailerons respond well and it is capable of all combat maneuvers. Spoilers fitted along the leading edge project automatically at about 300 kph (186 mph) when the plane is in a gliding angle and at about 450 kph (279 mph) when in a climbing position. Turns are not attempted at speeds of less than 350 kph. If throttle is advanced too quickly at less than 7,000 rpm, engines are likely to fail, a characteristic which has resulted in a number of takeoff accidents.
A four-jet version, the Me-264, designed for bombing and long-range reconnaissance, was first flown in December, 1942, and was to have been ready for combat in the summer of 1945. Messerschmitt was also well along on a modification of the 262 which would have attained a speed of 575 mph and been capable of flying for two hours at 27,000 feet without belly tanks.
The Heinkel 280, a parallel development of the Me-262, did not reach operational stage. Differing externally in its twin fins and rudders, it otherwise closely resembled the 262.
Spotted in flight, Germany's Volksjaeger is the most awkward-looking German airplane extant. On the ground, its high wing, dihedral tail, and top-side engine nacelle give it the lines of a single-engine amphibian.
Originally scheduled for production in September, 1944, the Heinkel 162 was test flown for the first time just three months later. Apparently, the early tests were successful, for the German high command set up a production schedule which would deliver 500 of these ships to the Luftwaffe during the first thirty days of production, would eventually send 1,000 Salamanders into action every month. Actually, only 140 of these strange planes had been completed by the end of the war. So the airplane which was to engage Allied fighters in combat and thus force our pilots to jettison extra fuel tanks necessary for escort range never really contributed to the final Reich defense. It is, nevertheless, an interesting ship from a design standpoint.
A single-jet type with on-deck endurance of about 20 minutes, the He-162 was fashioned entirely from nonstrategic materials. The one-piece shoulder-high wing is all-wood except for metal tips, with space between the wooden spars accommodating 40-gallon fuel cells. The metal flaps, which extend along the sharply tapered trailing edge from the fuselage to the ailerons, have maximum depression of 45° with hydraulic motivation. Semi-monocoque in structure, the fuselage is flush-riveted throughout, is extremely clean aerodynamically, and permits stowage of 168 gallons of fuel in the bulbous tail cone. Pilots enter the single-place cockpit through the roof, are ejected by an explosive cartridge when bail-out is necessary. A small ship with some of the design features of the V-1 bomb, the Volksjaeger has wing span of 23'8" and measures 28'8" in length. With only two guns, either MK-108 or MG-151, mounted low on the sides, the He-162 could do little more than annoy Allied escort pilots in direct combat.
Climbing 4,200 feet per minute at sea level, exceeding 522 mph at 19,700 feet, the 5,940-pound airplane was ideally suited to nuisance raids on attacking Allies. With Luftwaffe operations from small fields dictated by the retreat of German ground forces, its ability to take off in 875 yards on jet power alone or 415 yards with assisted takeoff unit was an important factor. However, full throttle range of 242 miles with maximum fuel load was inadequate in the face of round-the-clock and round-the-compass raids by the Allies. So the Heinkel 162, which combined the best ideas of Heinkel and Messerschmitt, the best jet units of Heinkel-Hirth and Jumo, became a symbol of the whole bottom-of-the-barrel, last-ditch German army. Today, it rests harmlessly in a hangar at Freeman Field, Indiana.
Pilots who have flown both the Me-262 and the Ar-234 rate the Arado bomber first in terms of the duties for which it was designed. Developed from the Ar-234A which it resembles closely except for the former's jettisonable wheel undercarriage and landing skids, the Ar-234B was first flown in December, 1943, went into production with slight modification in June, 1944, and was sighted by Eighth Air Force crews in November of that year.
Powered by two Jumo 004 jet units, the 234 attains a maximum speed of 470 mph at close to 20,000 feet, has a service ceiling of 37,700 feet. Maximum bomb load is 2,000 kg, but operations were generally limited to half that amount. With a load of 1,500 kg, the 234 requires 2,000 yards for takeoff but this can be reduced by 50 per cent with ATO rockets.
Unlike other medium bombers, the 234B is a single-seater, the pilot's compartment in the nose affording excellent vision. There are no forward firing guns, two MG 151/20 guns in fixed position firing aft comprising the normal armament.
Bigger than the 262, it is slightly more than 41½' long and the wing spans a shade over 47'. Maximum all-up weight for takeoff is 19,500 pounds which can be increased to 22,000 pounds with ATO rockets.
First used for reconnaissance flights over England, it was later assigned to fighter-bomber duties. Total production when the war ended was not more than 200.
Mass production of a "C" series, powered by four BMW 003 turbine jets, each developing 1,800 pounds thrust at sea level, was planned for March, 1945. When planned output of 500 per month was 50 or less production was abandoned in favor of the 262.
According to Flugkapitan Joachim Carl, Arado test pilot, the "C" was between 110 and 125 mph faster than the "B." Carl claims a top speed of 520 mph at sea level, without bombs, and ventured that the plane might move even faster except for difficulties due to airflow around the jet unit cowlings. Undercarriage of the "C" was strengthened to increase bomb load and the nose wheel enlarged. Forward firing 30-mm cannon were to have been added, the cabin pressurized, and the external bomb load partially concealed by means of a concave carrier. These and other modifications resulted in generally increased performance over the "B" except for operational range, which was shortened by about 30 per cent.
To most people on this side of the Atlantic, the Dornier 335 is a very unusual, very new propellered German type revealed during the final hours of the Luftwaffe. And few Allied types can challenge the design peculiarity of this aeronautical hybrid. But the double-ended Dornier was actually born more than eight years ago, only to languish until 1942 when Hitler first authorized production.
In performance this strange plane more than matches the oddity of its lines. Powered by a pair of DB-603E liquid-cooled engines arranged in tandem, it has attained a speed in excess of 500 mph with both 12', 3-blade propellers in operation. Operating on one engine, it can move along at a 350-mph clip for several minutes.
A big airplane by any standard, the unusually rugged 335 weighs more than 18,000 pounds with standard equipment and loading, actually tops 22,000 pounds in certain subtypes. With wing span and length of approximately 45', it was originally built as a single-seater only to emerge during the last year of war with a pig-a-back seating arrangement for training and reconnaissance utilization. Intended as an antidote for De Havilland Mosquito raids on the Reich, the Dornier has a wing loading of 41 psf in the standard model, wing loading of 35 psf in one high altitude type. However, interchangeability of armament and equipment brought wide divergence in gross loading on various missions.
That the Dornier qualified as an all-purpose airplane is perhaps best evidenced by operating specifications. With a 520-gallon main tank installed behind the pilot's compartment, two wing tanks, two drop tanks, and a bomb bay fuel cell, the big ship carried a total of 1,000 gallons of gasoline and boasted a range of approximately 2,400 miles. With internal and external belly tanks removed, the Do-335 carried a single 1,000-kg, two 500-kg bombs, or ten 70-kg anti-personnel missiles in the bomb bay, along with one 250-kg bomb in each drop-tank shackle. The full-up fighter installation included one 30-mm gun firing through the propeller hub, one 20-mm gun on each side of the nose cowling within the propeller arc, and one 20- or 30-mm gun in each wing. Although pilots had little chance for survival in bail-out because of the rear prop and large empennage, they were well-protected in the air with a bullet-resistant glass windshield and cockpit enclosure, an armored bulkhead between cockpit and main fuel tank.
Structurally, the Do-335 is neither unique nor commonplace, with certain refinements providing interesting but hardly spectacular variations on a standard monoplane theme. The trapezoidal wing, built around a heavy spar, has stressed metal skin, squared tips with detachable corners, leading edge de-icer, stowage for master unit of remote indicating compass, hydraulic tanks, oxygen bottles. On the A-6 version, radar antennae are mounted outboard on each wing. The all-metal monocoque fuselage is distinguished only by circular radiator in the nose, jettisonable mounting for rear propeller, cushioned stringers for hollow shaft to rear propeller, and explosive canopy release. In two-place models, the extra seat is above the leading edge of the wing and faces into the fuselage, with only the fuel tank separating this seat from the rear engine. Altogether the Do-335 stands as a good idea but something less than a great airplane. It may, however, provide several design features for planes of the future.
This article was originally published in the December, 1945, issue of Air News with Air Tech magazine, vol 9, no 6, pp 17-24.
The original article includes 23 photos with examples of each of the types discussed plus the Fl-282 helicopter and a bulldozer crushing a Fw-190.
Photo credits to USAAF, Harold G Martin, ATSC, British Combine, Air News.