POWER PLANT: One Walter HWK 509C liquid-fuel rocket engine, rated at 2,400 kp thrust (main chamber: 2,000 kp thrust, auxiliary chamber 400 kp thrust)
PERFORMANCE: 569 mph (estimated)
COMMENT: In 1944 the Arado design team proposed two liquid-rocket engines powered reconnaissance versions of the Arado Ar 234 “Blitz” (Lightning) high-speed bomber. The Arado Ar 234R, as it was designated, would consist of a regular Ar 234C frame but without turbojet engines. Instead two pods were installed under the wing, each containing a Walter HWK 109-509A bi-fuel rocket engine (project Ar 234R-1A). The second project Ar 234R-1B was to be powered by a Walter HWK 109-509C two chamber liquid-fuel rocket engine mounted in the rear section. Therefore a cowling would have been installed in the rear fuselage underneath the rudder. The upper rocket engine called “Steigofen” (Accelerate chamber) delivered 2,000 kp and was to be used for climbing to altitude while the lower rocket engine, “Marschofen” (Cruising chamber) delivered 400 kp thrust and was used to power the aircraft during horizontal flight. During return flight – over a distance of more than 155 miles – the aircraft flew as a glider without power. The wing had a laminar profile with its maximal thickness at 50 to 60% chord. The glide ratio was calculated to 1:14.
Because of the limited fuel capacity and short endurance of the rocket engines the Ar 234R-1b was to be towed by a Heinkel He 177 “Greif” heavy bomber. A possible reconnaissance mission in the London area was calculated as follows: After take-off from a Luftwaffe base near Paris the aircraft was towed to the operational altitude of app. 26,247 ft, reached near Calais. After release of towline with “Steigofen” at full throttle the aircraft was powered at a speed of app. 506 mph to an altitude of app. 55,775 ft. This height was reached in a few minutes app. near the coast of Dover. During horizontal flight intermittent ignition of the “Marschofen” accelerated the aircraft with 569 mph to the target (i. e. London). After photo mission the aircraft flew back to the coast of England at a speed of 541mph and the descent back to the home base was flown as a glider. The mission was estimated for 21 minutes.
Although the Arado Ar 234R-1B project was promising it was abandoned in favor of the DFS 228 reconnaissance rocket-driven glider giving even better ceiling of 75,460 ft (Ref: 16).
TYPE: Test glider for Lippisch P. 13a supersonic ramjet project
ACCOMMODATION: Pilot only
POWER PLANT: None
COMMENT: During work on the Lippisch P.13a supersonic ramjet project the Lippisch team proposed to build a test glider in order to study the flight characteristics of this revolutionary design. So a test glider was built by students from technical universities of Darmstadt and Munich, designated DM-1 (Darmstadt-München 1). At the end of the war the prototype of this test glider had not been finished when it was captured by US forces at the Prien airfield in Bavaria. Prof. Theodore von Karmann, a high capacity in aerodynamics in supersonic airflow, (native Hungarian, worked in Germany, later in the US) proposed to complete the test glider by Lippisch’s team. The aircraft was then shipped to the USA where it was test flown. According to NACA the results were positive and lessons learned were incorporated into NASA’s research as well as service aircraft of the 1950s. Mainly the Convair Company recognized the advantage on the Lippisch P.13a design and built the delta-aircraft XF2Y-1, XF-92, F-102, F-106, and B-58 (Ref. 19, 23)
TYPE: Test glider for the turbojet powered Gotha Go 229
ACCOMMODATION: Pilot only
POWER PLANT: None
PERFORMANCE: Not available
COMMENT: During summer 1943 the RLM interest in a pure flying wing had waned. Despite this loss of official interest, the Horten brothers continued to work on their jet fighter project which they had designated Horten Ho IX, and although entirely unauthorized by the RLM, construction work on a prototype had already started at Göttingen. To explore the aerodynamic characteristics of the revolutionary fighter thoroughly before attempting powered flight trials, the first prototype, the Ho IX V-1, was intended from the outset for testing as a glider before the installation of the planned BMW 003 turbojets, and was provided with a fixed tricycle undercarriage, the legs of the aft members being enclosed by swept aerofoil-section fairings. It was not until early 1944 that the RLM became aware of the existence of the Horten prototype and issued instructions that powered trial should be initiated. During spring 1944 the Ho IX V-1 had performed its first successful gliding trials and showed highly favourable results. But further trials terminated abruptly when the prototype crashed during a landing attempt. Meanwhile work began on the construction of a second prototype, Horten Ho IX V-2. The center section, accommodating the cockpit, power plants and undercarriage wells, was of conventional welded steel-tube construction with plywood skinning. Powered by two Junkers Jumo 004B turbojet engines, the Horten Ho IX V-2 made its test flight in January 1945.