Source: U.S. Army Signal Corps
Found by troops of Combat Command A, 9th. Armored Division, 1st. U.S. Army in April 1945 was the remains of Messerschmitt Me 163B V13, Werk Nummer (W.Nr.) 10022, fuselage code VD+EV. The location was a airfield hangar in Pölzen, Germany located to the northeast of Leipzig. While the men of Combat Command A likely did not know it at the time they came across the ruins of the aircraft, the V13 had been the start of the further development of the Me 163 rocket fighter that ultimately culminated in the Messerschmitt Me 263 (also designated as the Junkers Ju 248).
One of the most serious problems with the Me 163B rocket interceptor was the ravenous consumption the Walther HWK 509 A-2 bi-fuel rocket motor had for the reactant propellants, T-Stoff and C-Stoff. Once the Me 163B achieved operating altitude, the aircraft had only 2.5 minutes worth of powered flight left before the tanks ran dry. Typically, given the volatile and explosive nature of the fuels, pilots would often exhaust the entire fuel supply rather than risk having fuel onboard while in combat, let alone coming to a landing which risked causing a detonation if the touchdown was rough. In combat operations, it meant that the range of the Me 163B was severely restricted and unless airfields operating the rocket fighter were near known bomber routes, the Me 163B was more or less impotent. In fact, when U.S. Intelligence determined an airfield was housing a Me 163 unit, they advised U.S. Army Air Force bomber units to simply plot bombing strike avenues to avoid the airfield. Another problem with the Me 163B was that is had no landing gear outside of a central skid. It took off atop a two-wheeled dolly which was then jettisoned once the plane was airborne. Upon landing, it had to be recovered by a special trailer pulled by a three-wheeled tractor called a Scheuschlepper. The V13 was the first step in overcoming the first of these two main concerns with the fighter.
The V13 was the first to trial a new Walther rocket engine, the HWK 509 C. While the fuels were the same, the biggest difference was the addition of a cruise chamber. The HWK 509 C's main chamber produced 3,750 pounds of thrust but the cruise chamber only provided 660 pounds of thrust. The idea was that for take-off, both chambers would be engaged for a total of 4,410 pounds of thrust. Once the aircraft was at operational altitude, the main chamber would be shut off and the aircraft would fly only on the cruise chamber. As such, the new engine provided up to 6.5 minutes of powered flight before the fuel ran out. The V13 was much the same as the standard Me 163B except that the tail was modified to accommodate the cruise chamber which was to be used in the new development of the aircraft which was then called the Me 163D. The first flight of the V13 took place in December 1943 and the last known flight occurred on May 14, 1944. Two other Me 163B aircraft were part of the Me 163D project and these were the V10 (W.Nr. 10019, fuselage code VD+ES) and the V18 (W.Nr. 10027, fuselage code VA+SP). The V10, having originally been used to test a BMW rocket motor and a revised fuel tank system, was repurposed to trial the tricycle landing gear that was to be used on the Me 163D. The V18 was also refitted with a HWK 509 C engine and on July 6, 1944, pilot Rudolf Opitz took the aircraft up for a calibration flight and the engine was at maximum thrust and as it accelerated, the critical Mach number was exceeded. Opitz cut fuel to the engine which put the V18 into a steep dive Optiz was only able to recover feet from the waters of the Baltic Sea. After landing, the entire rudder was missing and readings taken during the flight showed the V18 had attained a speed of 702mph.
The results of testing with the V10, V13, and V18 culminated in the Ju 248 which was a nearly complete redesign of the Me 163 fighter. The designation Junkers Ju 248 came into play as work on the project was shifted to Junkers in the spring of 1944 in light of the Messerschmitt company's other development work and production obligations. The name would revert to Me 263 by August of 1944. The new aircraft utilized a new fuselage that incorporated a bubble canopy, retractable landing gear, and a HWK 509 C-4 bi-fuel engine which it was estimated would give the Ju 248 a maximum powered endurance of between 9 to 15 minutes altitude depending. While better than the maximum 7.5 minutes of total powered endurance with the Me 163B, it was not a significant increase overall though the ability to be more mobile on the ground lowered the time it took to for ground crews to turn the aircraft around for another sortie.
As it was, the Ju 248 V1 was completed and performed well in unpowered, towed testing but it was never flown under power and ended up captured by the Soviets who shipped it back to Russia for study. The Mikoyan-Gurevich I-270 rocket interceptor, first flown in 1946, drew heavily from the Me 263 but the entire concept of a rocket powered, point interceptor was flawed and the I-270 was abandoned.
