Messerschmitt Me 262 F-2b, III.-JG 53, Kassel, 46

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Some background:
The Messerschmitt Me 262 F was a series of multi-purpose jet planes designed by Messerschmitt for the Luftwaffe that entered service during the final phase of the Second World War in Europe. The aircraft’s design was begun in the summer of 1943 under the project handle P.1099, intended as an improvement to the successful Messerschmitt Me 262 jet fighter and also as a replacement for the Arado Ar 234 bomber/reconnaissance aircraft. The primary focus was on more payload, being either usable for more fuel (since early jet engines had poor mileage and therefore range and endurance) or for weapons, including bombs in an internal bomb bay that would enable the aircraft to fulfil a similar tactical role as the British de Havilland Mosquito. Beyond this high-speed bomber (Schnellbomber) variant, the P.1099 would also be a suitable basis for a fast reconnaissance plane, interceptors and night fighters, and trainer versions were also planned.

The Messerschmitt P.1099 was a 12 m long, conventional-looking aircraft with a wingspan of 12.6 m. It had a much wider fuselage than the Messerschmitt Me 262. It had a circular shape with a diameter of 1.7m (5 ft 6¾ in) and the cockpit was now moved closer to the aircraft’s nose, above the front landing gear well. The baseline aircraft featured a side-by-side cockpit for a crew of two, even though different layouts were envisioned for the specialized variants, including single-seaters. To save development time and to use existing jigs and tools as much as possible, the P.1099 retained the wings and the tail section of the Me 262A-2a. Despite a higher total weight (the P.1099’ MTOW was about 3 tons higher), the planned powerplants were initially two uprated Junkers Jumo 004 turbojet engines, later to be replaced by more powerful Heinkel HeS 011 turbojets.

In January 1944 the P.1099 was accepted by the RLM and received, despite the aircraft’s different structure, the designation “Me 262 F”. The first variant, the Me 262 F-1 (internally designated P.1099A), was the baseline aircraft under the handle “Jäger I”, a jet-powered single seat daytime fighter. There were three planned versions, differing mainly in armament: Version F-1a was armed with four MK 108 30 mm cannon in the lower fuselage, comparable with the earlier Me 262 A fighter, just with more fuel and ammunition. Version F-1b carried two MK 103 30 mm cannon with longer range, firepower and ammunition supply, and Version F-1c was a heavy daytime fighter with two MK 108 and two MK 103 cannon in the nose.
In parallel the Me 262 F-2 was developed as a more heavily armed and armored variant, as a dedicated heavy bomber interceptor (“Pulkjäger” or “Zerstörer”) under the handle “Jäger II”. Again, three versions were foreseen: Version F-2a would be armed with a single MK 108 cannon and a heavy MK 112 55 mm cannon in the nose. Version F-2b was the same, but it was armed with a MK 114 50 mm cannon instead of the Mk 112. Both were single seaters with a heavily armored cockpit and canopy.
The F-2c was a more thoroughly modified two-seater version; it was armed with a single MG151/20 in a small nose turret, a pair of Mk 103 in the rear of the cockpit firing up- and backwards and two defensive MG 131 in remote-controlled FDL 151 barbettes in the tail. Due to the significant changes this model had the internal project designation P.1099B.
Another two-seater, the F-2d, remained very close to the original baseline aircraft with a crew of two in a side-by-side cockpit. This aircraft was armed with the standard four MK 108 in the nose, plus one launch rail under each wing for Ruhrstahl X-4 guided missiles, which were launched and steered by the second crewman via a wire connection with the mothership. This variant did not come to fruition, however, after the X-4 missile project had been cancelled in early 1945.
All P.1099 fighters also had hardpoints under the outer wings for racks with twelve 55mm R4M unguided air-to-air missiles each, a detail taken over from the Me 262 A, even though the fuel load had to be reduced to carry them. The radio equipment of all these versions would be a FuG 16, Peil G6, FuG 101 radio altimeter, FuBl 2 blind landing equipment, as well as the FuG 25a Erstling identification friend or foe transceiver.

Beyond these initial day fighter variants, further types based on the P.1099 airframe were envisioned, too. The F-3 was a dedicated night fighter version, developed in parallel to the Me 262 G. It was based on the F-2a heavy day fighter, but it carried a crew of two (the pilot and a rearward-facing radar operator) and was equipped with a FuG 240 “Berlin” radar set and a rotating dish antenna under a streamlined plywood cover in the nose. The armament consisted of four MK 108 under the nose, similar to the F-1a day fighter, plus two additional, upward-firing MK 108 cannon (“Schräge Musik”) in the rear fuselage.
Other proposed variants (with less priority, though) were the F-4 and the F-5, which were to become the basis for fast bombers and reconnaissance aircraft with only light defensive armament, typically only a pair of MG 131 in remote-controlled tail barbettes was to be carried. The F-4 resembled the baseline P.1099A, with two bomb bays in front of and behind the main landing gear wells and a crew of two seated side-by-side in a pressurized cockpit. Two MK 108 were carried in the nose, plus the MG 131 tail barbettes. The F-5 was similar but featured a glazed bomb aimer/navigator station in the nose instead of the MK 108’s and the glazing above the pilot’s station was reduced and asymmetrical. In both bomber variants the fuselage tanks were re-arranged to make room for a single SC 1.200 in the front bomb bay, but combinations of smaller bombs could be carried, too. Alternatively, mounts for up to three cameras or a 1.350 l auxiliary tank for extended range could be carried in the bays, too.

Initial flight tests of the Me 262 F in late 1944 showed severe directional instability: especially after fuel and ammunition had been depleted and the center of gravity shifted the aircraft tended to become nose-heavy and ditch down if it was not carefully monitored and trimmed by the pilot. To cope with this problem, the engine mounts were modified, so that the CoG was shifted back. Compared with the original Me 262 the engines were placed roughly 900 mm (35.5 in) further back under the wings. The emptying sequence of the fuselage tanks was also changed, and this mostly mended the problems. Another measure to mend the directional instability issues was the enlargement of the tail surfaces, even though later production aircraft frequently had smaller Me 262 A stabilizers fitted due to material shortages and simple lack of parts.- However, due to the higher weight the Me 262 F’s handling and agility were very limited – but most of its intended roles rather relied on speed, anyway, so that dogfights could be avoided.

From 1944 on the war situation worsened considerably, and production of the new Me 262 F superseded the A variant only on selected production lines. A disused mine complex under the Walpersberg mountain was adapted for the production of complete aircraft. These were hauled to the flat top of the hill where a runway had been cleared and flown out. Between 20 and 30 Me 262 Fs were built here until early 1946, primarily fighters, the underground factory being overrun by Allied troops before it could reach a meaningful output. Wings were produced in Germany's oldest motorway tunnel at Engelberg, to the west of Stuttgart. At B8 Bergkristall-Esche II, a vast network of tunnels was excavated beneath St. Georgen/Gusen, Austria, where fully equipped fuselages for the Me 262 at a planned monthly rate of 450 units on large assembly lines were to be produced from early 1945.

After the type’s introduction to frontline units in early 1945 further handling problems arose through the aircraft’ weight, resulting from its high wing load. Both starting and landing run were excessive, so that the number of airfields from which it could be operated was relatively small. No real short-term solution could be found without fully re-designing the wings, so that RATO bottles were frequently used to get a fully loaded Me 262 F up into the air from standard airfields. These were typically fitted to racks which were mounted under the fuselage, flanking the rear bomb bay.
The Me 262 F’s landing speed was dangerously high, too. A retrofittable brake parachute, housed in a simple tubular fairing under the tail, was developed to reduce the landing distance and save brakes, which frequently overheated and could set the landed aircraft aflame.

From the Me 262 F-2a “Pulkzerstörer I”, only a small number were built and eventually entered service. Its main armament, the MK 112, was a heavy German machine cannon produced by Rheinmetall-Borsig from 1945 on – in fact, the MK 112 was basically a scaled-up MK 108, a very compact weapon with relatively low weight. The MK 112 had a caliber of 55 mm and thus fired much larger shells than the 30 mm MK 108, but the rate of fire was significantly lower (300 rounds / min compared to about 600-660 rounds / min of the MK 108). This large-caliber gun was designed primarily to combat heavy bombers, its rate of fire would have been too slow for effective aerial battles with escort fighters – but the Me 262 F would not have been a dogfighter, anyway, so that the “hit-and-run” mission profile suited the aircraft well. Fire tests showed that a single MK 112 hit with mine grenades could destroy a bomber, and with a rate of fire of five shells per second this weapon could inflict considerably higher losses on the incoming streams of Allied bombers compared to other on-board weapons used on the German side. Only the unguided R4M missiles were as effective, but the MK 112 offered considerably higher accuracy and the opportunity to execute more than just a single attack run on an incoming bomber formation.
The MK 112 was mounted in the lower starboard section of the Me 262 F-2a’s nose, its barrel protruded more than 2 m (7 ft) from its nose. The gun’s drum magazine with sixty rounds partly took up the rear space of the cockpit behind the pilot and the gun mount even used up space of the weapon bay on port side, so that only a single MK 108 with 100 rounds as an additional weapon was mounted in the lower port side weapon bay.
Its sister, the Me 262 F-2b, remained on the drawing board, because its main weapon, the 50 mm MK 114 autocannon that had been derived from the 5 cm Pak 38 anti-tank gun, had turned out to be over-complicated, overweight and unreliable. A refined version was developed as the MK 214A, though, but after flight test from February 1945, but the weapon was not deployed operationally.

Only a handful Me 262 F-2a Pulkzerstörer were eventually fielded and operated before the end of hostilities – beyond the low production numbers the lack of fuel and loss of suitable airfields highly limited the aircraft’s potential. Probably less than ten were used by operational units, including JG 53 “Pik As”, in which they served alongside other interceptors, including other Me 262 variants. Typically, bomber formations were approached from the side of a bomber formation, where their silhouettes were widest, and while still out of range of the bombers' machine guns. This broadside-attack tactic was very effective, and the aircraft’s high speed allowed the interceptors to turn around 180° and make at least a second attack run from the opposite side, before the machines dashed off and returned to their bases.

General characteristics:
    Crew: One
    Length: 14,32 m (46 ft 11 in) overall
            12,00 m (39 ft 3¾ in) fuselage only, w/o brake parachute housing
    Wingspan: 12,61 m (41 ft 3¾ in)
    Height: 4,43 m (14 ft 6 in)
    Wing area: 24,2 m² (236 sq ft)
    Empty weight: 5.061 kg (11,148 lb)
    Loaded weight: 8.762 kg (19,300 lb)
    Max. take-off weight: 10.062 kg (22,163 lb)

Powerplant:
    2× Junkers Jumo 004 C turbojets with 12 kN (2,697 lb st) each

Performance:
    Maximum speed: 930 km/h (577 mph, 505 kn)
    Cruising speed: 805 km/h (500 mph, 438 kn) at 6.500 m (21,290 ft)
    Range: 1.340 km (830 ml, 728 nm) at 6000 m with internal fuel only
    Service ceiling: 11,450 m (37,570 ft)
    Rate of climb: 18 m/s (3,540 ft/min) at max. weight

Armament:
    1× 55 mm (1.96 in) MK 112 machine cannon with 60 rounds
    1× 30 mm (1.18 in) MK 108 machine cannon with 100 rounds
    Hardpoints under the outer wings for racks with twelve 55mm R4M unguided air-to-air missiles