Dornier Do 435 , Dragon Models, Parts scratch-built)

Type: Heavy all-weather fighter, Project

ACCOMMODATION: Pilot and navigator/radar-operator

POWER PLANT: One Daimler-Benz DB 603G liquid-cooled engine, rated at 1,874 hp plus one Junkers Jumo 004C turbojet engine, rated at 950 kp thrust

PERFORMANCE: Not available

COMMENT: The Dornier Do 435 was a heavy all-weather fighter  projected by the Dornier aircraft manufacturer for the German Luftwaffe during World War II. The design based on the twin-engine Do 335 „Pfeil“ (Arrow) heavy fighter, Luftwaffe‘s fastest piston-engined aircraft of World War II.
In May 1942, Dornier submitted a design Do P.231/1 for a twin-engine single-seat „Schnellbomber“-like high-speed bomber/intruder with a 1,000 kg bombload. The performance of this project was predicted to be better than other twin-engine designs due to its unique push-pull configuration and the lower aerodynamic drag of the in-line alignment of the two engines.The proposed front engine was a Daimler-Benz DB 605E and drove a puller-type propeller while the second DB 605E was located in the rear part of the fuselage and drove a pusher-propeller.
This project was selected as the winner after beating rival designs from Arado, Junkers, and Blohm & Voss. A development contract was awarded, by the RLM issuing the Dornier firm the airframe approval number 8-335, for what after many manfications would become known as the Dornier Do 335 „Pfeil“ (Arrow). In autumn 1942, Dornier was told that the Schnellbomber Do 335 was no longer required, and instead a multi-role fighter based on the same general layout would be accepted. This delayed the prototype delivery as it was modified for the new role.
The first prototype Do 335 V1 flew on 26 October 1943. However, several problems during the initial flight of the Do 335 would continue to plague the aircraft through most of its short history. On May 1944, the RLM ordered maximum priority to be given to Do 335 production. The first preproduction Do 335 (A-0s) were delivered in July 1944. But only approximately 22 preproduction aircraft were thought to have been completed and flown before the end of the war.
Early in 1943, while the first prototype of the Dornier Do 335 was under construction the Dornier design team dicussed the possibility to increase the performance of this new heavy twin-engine fighter. With the availability of the brand new incomming  turbojet engines the original Dornier project Do P. 231/1 was redesigned and had the company’s internal designation Do P.231/3.  The design was a single seat fighter aircraft with conventional empennage. The nose-mounted Daimler-Benz DB 603 piston engine remained unchanged while the rear DB 603 engine was replaced by a non specified turbojet engine. The piston engine would be used for normal flight and cruising and the turbojet added for high-speed flight.
On May 1943 Dornier submitted a further development, the single-seat  Do P.323/2. The DB 603 was replaced by a 1,874 hp DB 603G and a tail-mounted Junkers Jumo 004 delivering app. 900 kp thrust was provided. The two air intakes for the turbojet were lokated at both sides of the mid fuselage. The air-flow duct was later positioned on the rear back of the fuselage (project Do P.232/3). While the development made progress the RLM decided to convert the design to a night-/bad weather fighter. The air-ducts were relocated to the fuselage sides and a navigator/radar-operator was seated in between on the upper surface in a glass-covered cockpit. A FuG 220 “Lichtenstein SN-2” radar with “Hirschgeweih” (Stag’s Antlers) aerial array was provided. The airframe was designated Dornier Do 435 and was in summer 1944 in an advanced project stage. For modification as prototype the Dornier Do 335 V4 was envisaged. But in autumn 1944 the RLM decided to stop all further work on the project. Nevertheless, Allied intelligence reports from early May 1945 mention spotting a Do 435 at the Dornier factory airfield at Löwenthal (Ref.: 24).

Sack AS-6 V1 (Special Hobby Models)

TYPE: Experimental circular wing aircraft


POWER PLANT: One Argus As 10C-3 liquid-cooled engine, rated at 240 hp

PERFORMANCE: Na data available

COMMENT: The Sack AS-6 was a German prototype circular-winged aircraft built privately during the Second World War. It did not see production.
The aircraft was designed by Arthur Sack, a farm owner and amateur engineer from a little town near Leipzig. In his attempts to create a circular-winged aircraft he built five model aircraft, each with little success. He entered his fifth model, with a 1.25 meter diameter wing and 1.5 horsepower engine, in a 1939 competition for remotely controlled models with combustion engines. The models were to take off and land at the same point. None of the entries managed to do so. Sack’s model was unable to take off from the ground but flew when released by hand.
At the end of 1940 Sack started design of the AS-6, a full-sized, manned aircraft and successor to the earlier models. Its wing diameter was four times larger than the last model. He built it privately in a shed at his farm, using a wood construction. The Argus As 10 engine as well as the main landing gear from a Messerschmitt Me 109 was sponsored by ATG, a company at Leipzig, that assembled Junkers bomber aircraft. In 1944 the AS-6 prototype was finished and its design documents provisionally approved. Arthur Sack enlisted the help of the chief test pilot of ATG to test the aircraft. Approximately a dozen tests revealed multiple failings, especially in the undercarriage, and managed little more than a hop off the ground. The tests continued at an airbase in Brandis by a pilot in a Messerschmitt Me 163B unit based there. As the AS-6 did not appear on an inventory of seized items when US forces captured the airbase it is assumed that the plane was destroyed to prevent capture (Ref.: 24).

It is to note that the US Navy also planned to realize a disc-shaped Short Take-off/Landing (STOL) aircraft. In the late 1930s the Vought Company was working on an experimental twin engine, circular winged aircraft, the  V-173 Flying Pancake. After successful and promising flights the US Navy placed an order for two prototypes of a new carrier-based fighter aircraft, larger, heavier and more powerful than the V-177. Two prototypes oft he Chance Vought XF5U-1 Flying Flapjack were built made only ground runs and never lifted into the air. Due tot he end of WW II and with jet aircraft coming into service, the Navy finally canceled the project in 1947. Possibly a turbojet powered variant, the Vought Jet skimmer, was on the drawing board. Exact data are not available.