Wednesday, 11 November 2015

Restoration News: Heinkel He 219 Night Fighter. Part 3. German Dzib -Compiler-

Thursday, July 17, was an exciting day at the Paul E. Garber Restoration Facility, and another step towards the completion of one major aircraft currently undergoing restoration:  the wing of the Heinkel He 219 Uhunight fighter was prepared for its move to the Udvar Hazy Center in Chantilly, VA. The He 219 was Germany’s best night fighter in World War II, and possibly the best night fighter of the war. It was a piston-engine aircraft specifically designed for night fighting operation — a status it shared with only one other aircraft in the war, the American Northrop P-61 Black Widow. Notable features include the first steerable nose wheel on an operational German aircraft, the world’s first ejection seats on an operational aircraft, and cannons mounted to fire at an oblique angle (the so-called “Schräge Musik”).
The He 219 wing is rolled out of the paint booth
The easy part, using nothing but manpower: The He 219 wing is rolled out of the paint booth, standing 4 m (13 feet) high and about 19 m (63 feet) long.
The Museum’s He 219, built in 1944, has been undergoing restoration for many years. Its fuselage and engines are already exhibited at Udvar-Hazy Center. The wing — with a span of about approximately 19 meters (63 feet) — had undergone painting at the Garber paint shop, while being kept on a special-built, two-piece stand that would enable the restoration team to rotate the wing from an upright attitude to its normal horizontal position,  a necessary step to get the heavy and unwieldy object ready for transport on a flatbed truck.
The wing rotation crew. Seventy years after their original production, the He 219’s wing looks like new. Note the position of the Balkenkreuz on the outer wing panels. Although Luftwaffe regulations routinely specified that this insignia be placed parallel to the leading edge of the wing, Heinkel located it in a slightly different position, parallel to the spar, which was exactly reproduced by Museum experts. Clearly visible are the blue horizontal and yellow vertical stand the wing is mounted to.
On the morning of July 17, 2014, about a dozen employees from the restoration workshop and the Collections Processing Unit (CPU) were involved in flipping the wings 90 degrees, a process that took three hours and involved some heavy lifting, with the wings weighing in at about 2,223 kilograms (4,900 pounds), and the stand at an additional 454 kilograms (1,000 pounds).

To lift the wing from the first stand, straps are attached to the wing lifting fixtures. Here, Dave Wilson and Tony Carp check the position of these straps.
Within the weeks to come, the wing will be taken to the Udvar-Hazy Center where it will receive its final coat of green/blue Wellenmuster (wave pattern) camouflage paint, before being assembled with the fuselage later this year. Meanwhile, curatorial staff, restoration experts, and volunteers are working on the last major component toward the completion of the aircraft — the replacement of the He 219’s famous ”stag antlers” FuG 220 antenna array. The Museum’s aircraft lost its antenna at some point in its lifetime. An original FuG 220 antenna array from a European museum will be brought to the Udvar-Hazy Center later this year, where Museum staff will reverse-engineer the components, in order to complete the night fighter’s identity. Once finished, our He 219 will be the only aircraft of its kind on display worldwide.
After removing the first stand, heavy equipment is employed in rotating the wing 90°. Patiently and precisely, all equipment is put in place, and two staff members act as true “wingmen,” closely watching the wing as it is rotated.
Once on the ground, wing and stand are measured one more time to determine the needs for their final transport. Subsequently, the wing was rolled back into the paint shop, and is now ready to be shipped to Udvar-Hazy Center.
Evelyn Crellin is a curator in the Aeronautics Department at the National Air and Space Museum, Smithsonian Institution, Washington, D.C. Dave Wilson, museum specialist in the restoration workshop, contributed to this blog. (15)

A little descrption
The He 219, with its flattened fuselage sides, large engine nacelles and firmly set tricycle landing gear was not, at first sight, a particularly pretty aircraft. Its funny-looking nose, which made one think of a prehistoric reptile, bristled with radar antennas, known in military vernacular as ‘stag’s antlers’. In my opinion, the Heinkel was far less likely to be considered an aesthetically pleasing construction than any of its contemporary fighter designs.
Starboard side of the radar operator’s position  in He 219 A-0. [Kagero archive]Still, this odd looking machine duly gained fame as the most advanced night fighter design to see active service during World War Two. As the saying goes: ‘’.
When I saw the He 219 for the first time at Grove, nearly two years after its conspicuous debut with Maj. Streib at the controls, I was actually more interested in the Arado Ar 234 B. Hence, I gave the He 219 only a cursory glance. Later on, five He 219s were shipped, one by one, from Schleswig to the RAE (Royal Aircraft Establishment) at Farnborough. Shortly afterwards, I had an opportunity to fly three of those five. There were four He 219s of the A-2 variant from the first production run and one He 219 A-5. The latter was in fact the He 219 V11, which after an accident had been rebuilt to A-5 configuration [In fact, these were four He 219 A-7s and one He 219 A-2. The He 219 V11 was found in pieces at Heinkel Schwechat factory]. At Farnborough we were not supposed to focus on the He 219s’ performance and handling; we were instead to examine some of their onboard equipment, which was of great interest to the RAF. Nevertheless, I flew the Heinkels so many times that I was able to thoroughly test their handling.

From a pilot’s point of view, what impressed me most about the He 219 was the aircraft’s

superbly located cockpit. It was mounted relatively high and was accessible by a ladder.
Once the crew took their seats, a groundcrew member folded the ladder and stowed it in a purpose-designed hatch located in the port, lower part of the fuselage. The upper part of the cockpit’s canopy was made of a large, single piece of Plexiglas, hinged to starboard. Thus, the cockpit offered a practically unhindered all-round view. The cockpit itself was quite roomy, comfortable and well laid-out. The instrument panel was T-shaped as in most aircraft, with the engine control gauges located to the right.
Starboard side of the radar operator’s position in He 219 A-0. [Kagero archive]
The pilot and the radio operator sat back to back. They were equipped with ejector seats, their jettison mechanism powered by compressed air. In fact, the cockpit seemed fitted with every imaginable system known to date, which could enhance a night fighter’s operational effectiveness.
Initially, the He 219 was to be powered by Daimler-Benz DB 603 G engines rated at 1,900 hp on take-off, and 1,560 hp at 7,375 m. However, those powerplants were not ready in autumn 1943 when the first airframes began to roll off the assembly line at the Vienna / Schwechat plant. Therefore, DB 603 A engines, rated at 1,750 hp on take-off, and 1,850 hp (maximum output) at 2,100 m, were used instead. Such engines powered the He 219 A-2, the variant that I flew on many occasions. For example, on 21st August 1945 I piloted He 219 A-2, W.Nr. 210 126 [the correct Werknummer was 290 126] from Farnborough to Brize Norton. Nine days later I transferred another machine  (W.Nr. 310 109) [It was a He 219 A-7] via Abingdon to Brize Norton, and on 19th October I took the third A-2, W.Nr. 310 106, from Tangmere to Farnborough [It was also a He 219 A-7].
Unfortunately, I missed an opportunity to fly the later variant, the He 219 A-5 powered by DB 603 G engines [That must be an error as DB 603 G engines never went into production]. Nonetheless, I suspect that there were no substantial differences between the two variants as far as their performance was concerned.

The procedure for starting a DB 603 A engine was very simple: set the fuel cocks to tanks Nos. 2 and 3 (which were the main central and rear tanks); fuel pump on; push the throttle lever about one quarter forward, until some resistance could be felt; set the magneto switches to the ‘M 1+2’ position. The inertia starter was usually set in motion by an external power unit, although it could also be done from inside the cockpit. Press the starter control for 10 to 20 seconds, then let go, pull and move to the left in order to prime the engine. Once the engine had started, adjust the throttle so that it was running at 1,200 rpm, until the oil and fuel gauges indicated the correct readings. Let the engine warm up by running it for three minutes at 1,500 rpm, then check the magnetos at 2,000 rpm.
Before taxiing out all trimmers were set to neutral, the radiator flaps opened, and the air pressure of the ejector seats checked. In the case of the pilot’s seat the correct pressure was 80 kg / cm2, and for the radio operator’s seat the correct value was 50 kg / cm2. The aircraft was easy to manoeuvre on the ground, although the brakes, which were very effective, had to be handled carefully. Immediately before takeoff, the propeller pitch control was set at the 12:15 clock position, and the wing flaps lowered for takeoff. The takeoff run with full load was impressive – some 1,500 m with the engines at 2,700 rrpm and 1.4 ata of boost.
According to German reports I had read, the He 219’s engines had surplus power for take-off, which allowed the aircraft to safely get off the ground and climb even if one of the two power units failed. One pilot allegedly took off on one engine and climbed away with the landing flaps and undercarriage lowered! If there had been a grain of truth in that report, it must have related to a rocket-assisted take-off, on a very long runway. 
Main instrument panel with side panels of later series. [Visualisation 3D Marek Ryś]

It is my opinion that the He 219, especially the A-2 variant, was woefully underpowered. The failure of one engine, especially on take-off at night, must have been a particularly nasty surprise, for at 220 kph the aircraft could barely fly level, let alone gain altitude. When you take into account the tendency to stall as the undercarriage is retracted whilst climbing - a not uncommon thing in practically all types of aircraft - passing through the 15 to 90 metres of altitude level must surely have been a hairy experience for He 219 pilots. The aircraft would heave off the ground at 170 kph, and it was only at 15 metres that the pilot could attempt to raise the landing gear, this manoeuvre being too dangerous below that height due to the aforementioned tendency to stall. When the aircraft reached 250 kph and 150 metres of altitude, flaps could be retracted; during that manoeuvre the aircraft again was prone to stalling. Climbing could be commenced in earnest at 300 kph, with the engines at 2,600 rpm and 1.3 ata of boost. Only then could the He 219’s excellent stability in the air be observed.
Optimum climb rate was achieved at 300 kph, which dropped to 280 kph as the aircraft gained altitude. Once at 10,000 metres, it was practically impossible to climb any higher. Upon reaching the desired altitude the radiator flaps had to be closed and the engines kept at 2,300 rpm and 1.3 ata of boost. In order to extend the aircraft’s range the pilot could reduce the engine revolutions to 2,000 rpm with 1.05 ata of boost.
Above 6,100 metres the aircraft reacted markedly more sluggishly to full throttle. The maximum speed attained during the tests was 608 kph, which was lower than indicated by the German manuals. For the fuel system to function properly, it was necessary to use up half of the fuel stored in tank Nos. 2 and 3 (which left a total of 1,000 litres of gasoline in them), then switch to tank no 1 and empty it.

The cockpit heating and de-icing system was very efficient. The automatic pilot was easy to use and trustworthy. The He 219 was certainly a superb all-weather fighter. The landing procedure was markedly simple: close the radiator flaps, set the pitch control at the 12 o’clock position, at 300 kph lower the landing flaps, and at 270 kph drop the landing gear. The upwind turn while coming down to land could be made at 250 kph. At that point the landing flaps were fully extended, and the fuel pumps switched off. The aircraft would steadily lose altitude at 225 kph, and once above the runway, the pilot would throttle back to 200 kph. The prescribed touchdown speed was 160 kph.

The landing was very easy. However, it was not advised to keep the front wheel in the air for long, since the initial phase of the landing run was performed at high speed, and the aircraft had to be slowed down through resolute use of the brakes. Thus, it was important to check, prior to landing, the pressure in the brakes, which had to be not less than 60 kg/cm2. If the value was not as required, a pilot was expected to press

a button located next to the brake pressure gauge, until the desired reading was obtained.
Revi 16 B sight with additional control levers led behind  the armour plate to the cockpit.A landing run in windless weather was about 650 metres long. Windy conditions affected the He 219’s lateral stability on touchdown.
In my opinion, derived from my personal experience in flying the He 219 A-2, the aircraft did not measure up to its acclaimed reputation.
It was a good night fighter, but one with the serious flaw of underpowered engines, an unforgiving fault in a twin-engined aircraft. Losing one engine in a He 219 on takeoff was very dangerous, as it was on landing since the other engine did not provide enough power for another circuit. Overall, the He 219’s mediocre performance made it hardly suitable for the role it was designed for, which was fighting the British Mosquito. However, it was a deadly adversary against four-engined bombers.

One can only wonder what effect the He 219 would have had on the night air war over Germany, had the Luftwaffe’s Director General of Equipment not been so opposed to its development and operational use, and had Ernst Heinkel delivered his fighter to frontline units in sufficient numbers”.