Messerschmitt Bf-309
https://en.wikipedia.org/wiki/Messerschmitt_Me_309
http://www.airpages.ru/eng/lw/me309.shtml
The Messerschmitt Me 309 was proposed as an advanced replacement for the venerable Bf 109 fighter. Its design features included tricycle landing gear, retractable radiators and coolers and a pressurized cockpit. These concepts were first tested on four modified Bf 109F prototypes, the Bf 109V24, V30, V30A and V31. Nine prototypes were planned, with the first, the Me 309V1, being rolled-out in June of 1942. However, during taxiing trials, wobble problems were experienced with the nose gear (which had been utilized instead of a conventional "tail-dragger" layout in hopes of preventing this very problem). After trying several different tail configurations (sources vary between two and five), the V1 took to the air, but more problems arose with the cooling system, resulting in a brief flight of only seven minutes duration. Three additional protoypes were built, but so many accidents (mostly involving the troublesome landing gear) occurred that parts meant for the remaining prototypes were needed to keep the existing aircraft flyable.
Some history and backgrounds:
After the completion of these trials, the Me 309 V1 was flown at Leipheim for a series of measured take-off and landing trials from the airfield's concrete runway. These trials revealed that unstick speed at 8,157 lb was 112 mph, rising to 124 mph at 9,039 lb. The Me 309 V1 still displayed a tendency to swerve from the runway during takeoff and landing , and also offered some directional instability in level flight at high speeds, and in November 1942 the prototype was fitted with an enlarged and completely redesigned vertical tail assembly originally intended for the Me 309 V3. On November 11, 1942, after the completion of this modification, the Me 309 V1 was demonstrated for Oberts Adolf Galland, and on the 20th of the month it was flown at the Rechlin
Erprobungsstelle by the RLM test pilot Beauvais. Two days later Beauvais flew it in mock combat with a Bf 109G, discovering that the older fighter could turn inside the Me 309 which could only escape its opponent by means of its superior speed.
After one further flight test, Beauvais submitted his report as follows: "The Me 309 will be acceptable after some improvements but will present difficulties to the average fighter pilot. Control forces are extremely high by comparison with current fighters, and landing on the nosewheel will give problems to combat pilots at operational fields. With full armament the aircraft will be barely 30 mph faster than the Bf 109G, and there would seem to be no real advantage to introducing such a fighter when a superior aircraft [i.e., the Fw 190D] will be soon available.
The second prototype, the Me 309 V2, was flown for the first time on November 29, 1942, but as the aircraft touched down the nosewheel leg collapsed and damage was so extensive that the aircraft had to be written off. The Me 309 V2 had differed from the V1 primarily in having a DB 605B engine in place of the DB 603A-1. The latter powerplant was, in fact, to be replaced in the Me 309 V1 by a DB 605B in March 1943, and by that time the first prototype was flying with yet another vertical tail surface arrangement which had been adopted during the previous December, and no fewer than four different tailplanes had been fitted before tolerably acceptable results had been achieved. The first prototype was joined in the test program decided to restricted the program to four
Versuchs aircraft.
The fourth and last prototype, the Me 309 V4, which was intended for armament trials, was finally completed and flown in July 1943. DB-605B-powered, the Me 309 V4 carried the exceptionally heavy armament that Messerschmitt had proposed for the Schwerer Jäger version, this comprising two 13-mm MG 131 machine guns in the fuselage, a 20-mm MG 151 and a 13-mm MG 131 in each wing root and a 30-mm MK 108 immediately outboard of each main undercarriage member attachment point. The MK 108s were partly enclosed by streamlined bodies on the upper wing-surfaces, extending aft of the trailing edges and similar to those tested by the Bf 109 V31. With full armament and 193.5 Imp. gal of fuel, the me 309 V4, weighted 10,736 lb and attained 360 mph, this performance being some 15% lower that calculated by Messersschmitt.
After initial trials at Augsburg, the Me 309 V4 was to have been transferred to Leipheim for further testing, but before the transfer could be effected the aircraft was destroyed in air attack. The Me 309 V3 was subsequently employed for tests in connection with the pressurized cockpit and ejector seat arrangement for the Me 262, and the original Me 309 V1 performed various trials in connection with its tricycle undercarriage and reversible-pitch propeller.
Prior to the discontinuation of Me 309 development, several production versions of the basic design were proposed, these including the Me 309A-1
leichter Jäger with an armament of two 13-mm MG 131s and a 30-mm MK 108, and the Me 309A-2
Scwerer Jäger with an armament similar to that tested by the Me 309 V4, and the Me 309B-1 dive bomber, with a similar gun armament to the A-1 and a pair of 551-lb bombs on racks beneath the wing roots. Alternative powerplants envisaged for these projected production variants were the DB 603G affording 1,900 hp at sea level and 1,560 hp at 24,280 ft. Yet a further development that proceeded no further than the drawing board was the Me 609 which comprised two Me 309 fuselages with standard port and starboard wings married by a constant-chord center wing section and a constant-chord tailplane.
Data and specifications:
Powerplant:
- Me 309V1: One Daimler-Benz DB 603A-1 V-12 inline liquid-cooled piston .
- Me 309V2,V3,V4: One 1,475 hp Daimler-Benz DB 605B V-12 inline liquid-cooled piston.
- Me 309A, B: One DB 605B, or one 1,750 hp Daimler-Benz DB 603A, or one Junkers Jumo 213.
- Me 409: ?
- Me 509: One DB 605B
- Me 609: Two 2,000 hp Daimler-Benz DB 603G
Dimensions:
- Me 309V4:
- Span: 36 ft 1 in / 11 m.
- Length: 32 ft 7 in / 9.93 m
- Height: 11 ft 3 in / 3.43 m.
- Wing area: 177.39 sq ft / 16.5 m2.
Weights:
- Me 309V4:
- Empty: 3,530 kg
- Maximum: 10,736 lb / 4,870 kg.
Performance:
- Me 309V4:
- Max speed:
- 7,220 ft / 2,200 m: 360 mph / 580 km/h.
- Time to 13,125 ft / 4,000 m: 5 min 12 sec.
- Service ceiling: 37,400 ft / 11,400 m
- Range: 683 miles / 1,100 km.
Armament:
- Me 309V4:
- Two 30 mm MK 108 cannon in wings.
- Two 20 mm MG 151 cannon in wing roots (outer).
- Two 13 mm MK 131 machine guns in wing roots (inner).
- Two 13 mm MK 131 machine guns in fuselage above engine.
- Me 309A:
- Two 13 mm MG 131 machine guns.
- One 30 mm MK 108 cannon firing through propellor hub (Me 309A-1 only).
- Me 309B:
- Two 13 mm MG 131 machine guns.
- One 30 mm MK 108 cannon firing through propellor hub.
- Bomb racks under wing roots.
https://forum.warthunder.com/index....ct-premium-tier-3-german-prototype-fighter34/
Messerschmitt Me-109 Cz. 2
In 1943 the third G-series pre-production aircraft was modified to test a butterfly tail.
There was a small increase in top speed but at low speeds stability was a problem.
No further tests were made.
In 1943 a F-2 airframe was tested with 4 EG RZ85 rockets in each wing.
The installation had an unfavorable effect on the flight characteristics however
and no further experiments were made.