Category Archives: Luftwaffe

Deutschland / Germany

Nightfighter

Messerschmitt Me 262 with Heinkel/Hirth HeS 011A, (Frank/Airmodel, Vacu-formed, with parts from Revell)

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TYPE: Night and bad-weather fighter

ACCOMMODATION: Crew of two, pilot and navigator/radar-operator

POWER PLANT: Two Heinkel/Hirth HeS 011A turbojet engines, rates at 1.300 kp thrust each

PERFORMANCE: 540 mph at 19,685 ft

COMMENT: The Messerschmitt Me 262, nicknamed Schwalbe (German: “Swallow”) in fighter versions, or Sturmvogel (German: “Storm Bird”) in fighter-bomber versions, was the world’s first operational turbojet-powered fighter aircraft. Design work started before WW II began, but problems with engines, metallurgy and top-level interference kept the aircraft from operational status with the German Luftwaffe until mid-1944. The Me 262 was faster and more heavily armed than any Allied fighter, including the British turbojet-powered Gloster Meteor. One of the most advanced aviation designs in operational use during World War II, the Me 262’s roles included light bomber, reconnaissance and experimenat night fighter versions.
While the Messerschmitt Me 262 was not a difficult aircraft to fly, it possessed its share of idiosyncrasies, and some problems arose in the conversion of inexperienced pilots who had just completed their fighter training on piston-engined types. So it was obvious that traing would be simplified by the availability of a dual-control two-seater, and, accordingly, Messerschmitt evolved a suitable conversion trainer, the Messerschmitt Me 262B-1a.
Only some 15 examples of this trainer were delivered as the importance  attached to the introduction of the Me 262 as a nocturnal interceptor resulted in additional trainers on the assemblxy line being converted  as night fighters under the designation Messerschmitt Me 262B-1a/U1.
Whereas the Me 2626B-1a/U1 was a hurried adaption of the training model, the Messerschmitt Me 262 with two more powerful Heinkel/Hirth HeS 011A turbojet engines was considered as the definitive night-fighting sub-type for service from mid-1945. Structurally, the principal change consisted of the insertion of additional fuselage section fore and aft the tandem cockpits, increasing overall length more than 3.5 ft. This provided the necessary space to restore the 900 ltr resp. 600 ltr fuel tanks.
The first aircraft possessed similar radar to that of the Me 262B-1a/U2, and flight trials should begin in March 1945. The drag of the „Hirschgeweih“ array, with its eight 7-mm-diameter dipoles, was such that it reduced maximum speed by 30 mph. Various attempts had been made to streamline the antennae, resulting in the „Morgenstern“ aerial system in which the short antennae protruded through the pointed nose cone, and it was calculated that this would restore 30 mph of the speed loss. In the event, it was decided to standardize on the centrimetric wavelength FuG 240 „Berlin“ radar with a disc scanner housed in a plastic radome above the nose-mounted cannon, this affording little or no drag. The second variant of this design was to be fitted with two Heinkel/Hirth HeS 011B turbojet engines of 1.500 kp thrust each, equipped with a „Berlin“ radar, and a crew of three in a pressurized cockpit.  The Me 262 night fighter variants retained the standard forward firing battery of four 30 mm MK 108 cannon, and, in addition, provision was made for two similar weapons in a „Schräge Musik“ arrangement immediately aft of the rear cockpit (Ref.: 7).

Fighterbomber, Medium Bomber, Projects

Messerschmitt Me P.1101/28 (Resin, Frank Modellbau)

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TYPE: Fast bomber and destroyer

ACCOMMODATION: Crew of two (Pilot and radiooperator/navigator)

POWER PLANT: Two Heinkel-Hirth HeS 011 turbojet engines, rated at 1.300 kp thrust each

PERFORMANCE: 565 mph

COMMENT: This project study of 11. April 1945 (Little note: less than four weeks before the total collaps of the “Third Reich”!!!!) for a two seat “Schnellbomber” (fast bomber) and “Zerstörer” (destroyer) constituted a further development of the Messerschmitt Me P.1099, Me P.1100 and Me P.1101 series of proposals of 1944 on the basis of the original in service Messerschmitt Me 262.
Whereas the basic fuselage, spacious cockpit and tail surfaces of the mentioned follow-up proposals were retained, the two Heinkel-Hirth HeS 011 turbojets were relocated into the wing root to which the new wings having a leading edge sweep of almost 40 degrees were attached. An interesting feature of the design was that the mainwheels were to retract inwards to rest vertically in the fuselage between the fore and aft fuel tanks. Exactly how this was to be accomplished with the turbojets in the way is not clear from the documents. Although the final form of the fuselage nose portion had not been decided, the end of the war brought an early end of the project (Ref.: 16).

Fighter

Messerschmitt Me 263 “Scholle” (Plaice), (Huma)

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TYPE: Fighter interceptor

ACCOMMODATION: Pilot only

POWER PLANT: One Walter HWK 109-509C-3 dual-chamber liquid-propellant rocket engine,main chamber rated up to 2,000 kp thrust, auxiliary chamber 400 kp thrust

PERFORMANCE: 590 mph

COMMENT: The Messerschmitt Me 263 „Scholle“ (Plaice) was a rocket-powered fighter aircraft developed from the Messerschmitt Me 163 „Komet“ (Comet) towards the end of WW II. Three prototypes were built but never flown under their own power as the rapidly deteriorating military situation in Germany prevented the completion of the test program.
Although the Messerschmitt Me 163 had very short endurance, it had originally been even shorter. In the original design, the engine had only one throttle setting, “full on”, and burned through its fuel in a few minutes. Not only did this further limit endurance, in flight testing, pilots found the aircraft quickly exhibited compressibility effects as soon as they levelled off from the climb and speeds picked up. This led the Reichsluftfahrtministerium (RLM) to demand the addition of a throttle, leading to lengthy delays and a dramatic decrease in fuel economy when throttled.
This problem was addressed in the slightly updated Messerschmitt Me 163C. This featured the same Walter HWK 109-509B or C dual chamber rocket engine already trialled on the Me 163B V6 and V18 prototypes; the main upper chamber („Hauptkammer“) was tuned for high thrust while the lower „Marschofen“ auxiliary combustion chamber was designed for a much lower thrust output (about 400 kgf maximum) for economic cruise. In operation, throttling was accomplished by starting or stopping the main engine, which was about four times as powerful as the smaller one. This change greatly simplified the engine, while also retaining much higher efficiency during cruise. Along with slightly increased fuel tankage, the powered endurance rose to about 12 minutes, a 50% improvement. As the aircraft spent only a short time climbing, this meant the time at combat altitude would be more than doubled.
Throughout development the RLM proved unhappy with the progress on the Me 263 project, and eventually decided to transfer development to Heinrich Hertel at Junkers company. Alexander Lippisch remained at Messerschmitt and retained the support of Waldemar Voigt, continuing development of the Me 163C.
At Junkers, the basic plan of the Me 163C was followed to produce an even larger design, the Junkers Ju 248. It retained the new pressurized cockpit and bubble canopy of the Me 163C, with even more fuel tankage, and adding a new retractable landing gear design. On September 1944 a wooden mock-up was shown to officials. The production version was intended to be powered by the more powerful BMW 109-708 rocket engine in place of the Walter power plant.
Prior to the actual building of the Ju 248, two Me 163Bs, prototype V13 and V18, were slated to be rebuilt. V13 had deteriorated due to weather exposure, so only V18 was rebuilt, but had been flown by test pilot Heini Dittmar at a record-setting 702 mph velocity on July , 1944 and suffered near-total destruction of its rudder surface as a result of high-speed induced compressibility. It is this aircraft that is often identified as the Me 163D, but this aircraft was built after the Ju 248 project had started.
Hertel had hoped to install Lorin ramjet engines, but this technology was still far ahead of its time. As a stopgap measure, they decided to build the aircraft with a „Sondergeräte“ (special equipment) in the form of a „Zusatztreibstoffbehälter“ (auxiliary fuel tank): two 160 l external T-Stoff oxidizer tanks were to be installed under the wings. This would lead to a 10% speed decrease but no negative flight characteristics. Although Junkers claimed the Ju 248 used a standard Me 163B wing, they decided to modify the wing to hold more C-Stoff fuel. This modification was carried out by the Puklitsch firm.
In November 1944, the aircraft was again redesignated as the Messerschmitt Me 263 to show its connection with the Me 163. The two projects also got names – the Ju 248 „Flunder“ (Flounder)) and the Me 263 „Scholle“ (Plaice)). In early 1945, Junkers proposed its own project, the EF 127 „Walli“ rocket fighter, as a competitor to the Me 163C and Me 263.
The first unpowered flight of the Messerschmitt Me 263 V1 was in February 1945. Several more unpowered flights took place that month. The biggest problem had to do with the center of gravity which was restored with the addition of counterweights. Eventually, the production aircraft would have repositioned the engine or the landing gear installation to solve this problem. The landing gear was still non-retractable. The results of those first flights were pricipally satisfying.
Test flights were later stopped because of fuel shortages for the Messerschmitt Bf 110 towplanes. As the Me 263 was not a part of the „Jägernotprogramm“ (Emergency Fighter Programm), it was difficult to get the resources it needed. For the time being the plane was not expected to enter production but further development was allowed. The V2 and V3 were not yet ready. The V2 was to get the retractable landing gear and the V3 would have the armament built in. The next month both the V1 and the V2 had the two-chambered HWK 109-509C installed, correcting the center-of-gravity problems. They flew only as gliders.
In April, American troops occupied the Messerschmitt plant and captured the three prototypes and the mock-up. The V2 was destroyed but another prototype ended up in the US. The rest was handed over to the Russians, who then created their own Mikoyan.Gurewitsch I-270 interceptor (Ref.: 24).

Fighterbomber

Dornier Do 335B-2 (Dragon Models)

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TYPE: Destoyer, Fighter-bomber

ACCOMMODATION: Pilot only

POWER PLANT: Two Daimler-Benz DB 603E-1 liquid-cooled engines, rated at 1,900 hp at 5,905 ft each

PERFORMANCE: 474 mph at 22,000 ft

COMMENT: The Dornier Do 335 „Pfeil“ (Arrow) was a German World-War II heavy fighter built by the Dornier company. The Pfeil’s performance was much 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. It was Germany’s fastest piston-engined aircraft of World War II. The Luftwaffe was desperate to get the design into operational use, but delays in engine deliveries meant that only a handful were delivered before the war ended.
The first 10 Do 335A-0s were delivered for testing in May 1944. By late this year, the Do 335A-1 was on the production line. It was similar to the A-0 but with the uprated DB 603E-1 engines of some 1,800 hp take-off power rating apiece and two underwing hardpoints for additional bombs, drop tanks or guns. It had a maximum speed of 474 mph at 21 300 ft with MW 50 boost, or 426 mph without boost, and climbed to 26, 250 ft in under 15 minutes. Even with one engine out, it reached about 350 mph.
With the worsening of war situation development emphasis in the „Pfeil“ programme switched from the A-series fighter-bomber to the more heavily armed B-series „Zerstörer“ (Destroyer), and during the winter 1944-45 the first Do 335B prototypes were completetd at Oberpfaffenhofen. The initial B-series „Zerstörer“ were essentially similar to the Do 335A-1 apart from armament and the deletion of internal weapon bay, its space being utilized by a supplement fuel tank. The Do 335 V13 had a 15-mm MG 151 cannon in the forward fuselage replaced by 20-mm MG 151s, and was intended to serve as a prototype fort he Do 335B-1, and the Do 335 V14 had this armament supplemented by two 30-mm MK 103 cannon mounted just inboard oft he main undercarriage attachment points, this being the prototype fort he Do 335B-2.
These were destined to be the only B-series prototypes actually completed and flown, although six additional aircraft were under construction at Oberpfaffenhofen when further development was terminated. These were the Do 335 V15 and V16, respectively the second prototype oft he B-1 and B-2 models, the Do 335 V17 which was intended  as a prototype oft he  B-6 two-seat night and bad weather fighter similar to the Do 335 A-6 but posessing the same armament as that oft he B-1; The Do 335 V18 which was to have been the second prototype fort he Do 335B-6, and the  Do 335 V19 and V20 which would have been respectively  prototypes  for the Do 335B-3 and B-7 powered by DB 603LA engines with two stage superchargers, the former being a single-seater similar to the B-2 and the latter being a two-seater similar tot he B-6 (Ref.: 7, 24).

Medium Bomber, Reconnaissance

Heinkel He 119 A-0 (V6), (Valom Models)

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TYPE: Reconnaissance bomber

ACCOMMODATION: Crew of three

POWER PLANT: One Daimler-Benz DB 606A-2, twenty-four-cylinder liquid-cooled coupled engine, rated at 2,350 hp

PERFORMANCE: 367 mph at 14,755 ft

COMMENT: The Heinkel He 119 was an experimental single-propeller monoplane with two coupled engines, developed in Germany. A private venture by Heinkel to test radical ideas by the Günter brothers, the He 119 was originally intended to act as an unarmed reconnaissance bomber capable of eluding all fighters due to its high performance.
Design was begun in the late summer of 1936. A notable feature of the aircraft was the streamlined fuselage, most likely as an evolutionary descendant of the 1932-vintage Heinkel H 70 record-setting single-engined mailplane design, but without the He 70’s protruding canopy-enclosed crew accommodation existing anywhere along the exterior. Instead, the He 119’s forward fuselage featured an extensively glazed cockpit forming the nose itself, heavily framed with many diagonally braced windows immediately behind the propeller spinner’s rear edge. Two of the three-man crew sat on either side of the driveshaft, which ran aft to a “power system”, a coupled pair of Daimler-Benz DB 601 engines mounted above the wing center-section within the fuselage, mounted together within a common mount (the starboard component engine having a “mirror-image” centrifugal supercharger) with a common gear reduction unit fitted to the front ends of each component engine, forming a drive unit known as the Daimler-Benz DB 606, the first German aircraft to use the “high-power” power plant system meant to provide German aircraft with an aviation power plant design of over 2,000 PS output capability.
The DB 606 engine was installed just behind the aft cockpit wall, near the center of gravity, with an enclosed extension shaft passing through the centerline of the extensively glazed cockpit to drive a large four-blade variable-pitch airscrew in the nose. An evaporative cooling system was used on the first aircraft (V1), with the remaining prototypes receiving a semi-retractable radiator directly below the engine to augment cooling during take-off and climb.
Only eight prototypes were completed and the aircraft did not see production, mainly because of the shortages of DB 601 “component” engines to construct the 1,500 kg “power systems” they formed. The first two prototypes were built as land planes, with retractable landing gear. The third prototype (V3) was constructed as a seaplane with twin floats. This was tested at the “Erprobungsstelle Travemünde” military seaplane test facility on the Baltic coast, and was scrapped in 1942 at Heinkel’s factory airfield in the coastal Rostock-Schmarl community, then known as Marienehe.
On November 1937, the fourth prototype (V4) made a world class-record flight in which it recorded an airspeed of 314 mph, with a payload of 1,000 kg, over a distance of 1,000 km. The four remaining prototypes were completed during the spring and early summer of 1938, the V5 and V6 being A-series production prototypes for the reconnaissance model, and the V7 and V8 being B-series production prototypes for the bomber model.
These four aircraft were three-seaters with a defensive armament of one 7.92 mm MG 15 machine gun in a dorsal position, V7 and V8 having provision for a normal bombload of three 250 kg bombs or maximum bombload of 1,000 kg. V7 and V8 were sold to Japan in May 1940, and extensively studied; the insights thus gained were used in the design of the Yokosuka R2Y1 “Keiun” The remaining prototypes served as engine test-beds, flying with various prototype versions of the DB 606 and DB 610 (twinned Daimler-Benz DB 605) and the experimental DB 613 (twinned Daimler-Benz DB 603).
In 1944, a high-speed bomber development, designed as a private venture by Heinkel to test radical ideas by the Günter brothers, was the Heinkel He 519. It was designed to use the 24-cylinder Daimler-Benz DB 613, but the aircraft remained a concept and was abandoned at the end of the war. (Ref.: 24).

Fighter, Projects

Blohm & Voss Ae 607 (RS Models, Resin)

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TYPE: Experimental flying wing aircraft

ACCOMMODATION: Pilot only

POWER PLANT: One Heinkel-Hirth HeS 011 turbojet, rated at 1,200 kp thrust

PERFORMANCE: Unknown

COMMENT: The Blohm & Voss Ae 607 was a turbojet-powered flying wing design drawn up by Blohm & Voss in 1945. Very little is known about it and its existence was only confirmed end of the last century.
Early in 1945, a Blohm & Voss aircraft designer called Thieme began work on Drawing Number Ae 607 within the standard drawing numbering system at B&V and labelled it „Nurflügel-TL-Jäger“ („All-wing jet fighter“). His design for a jet fighter was radically different from anything that B&V had done before: A flying wing, it approximated to a 45° delta planform.
An all-wing design, the centre section has a V-shaped lower profile deepening its keel and is sharply tapered both front and rear, while the outer sections are sharply swept at approximately 45° and tapered, giving the leading edge a sweep greater than 45° and the trailing edge an M-shaped outline from above. The wing tips are turned down, giving them a slight anhedral.
A turbojet engine duct runs down the centre, with the Heinkel-Hirth HeS 011 engine installed towards the rear. A small tail fin is placed above the jet exhaust duct, while the pilot’s cockpit is set just in front of the engine, but still well aft, and is offset to one side to give the pilot room alongside the intake duct. It is covered by a teardrop canopy. Two small, low aspect ratio and untapered canard foreplanes sweep forward from either side of the nose intake.
The undercarriage comprises main wheels retracting outwards and twin tailwheels retracting on either side of the engine exhaust duct. On the ground, it sits with a marked nose-up attitude presumably to keep the air intake well away from any surface debris while take-off. Estimated performance as well as it’s conceptual formulation is unknown. The Blohm & Voss Ae 607 „Nurflügel-TL-Jäger“ never received a „P“ number (Project number) and was probably only intended to showcase ideas for solving particular problems facing designers when designing on a layout for fighters. The authenticity of the „Nurflügel-TL-Jäger“ has been questioned for years but, oddly enough, it has proven to be an entirely genuine wartime design (Ref.: 24).

Fighter, Projects

Heinkel He P. 1078C (Frank Airmodel, Resin)

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TYPE: Interceptor

ACCOMMODATION: Pilot only

POWER PLANT: One Heinkel/Hirth HeS 011 turbojet engine, rated at 1,200 kp thrust

PERFORMANCE: 480 mph at 32,800 ft

COMMENT: The Heinkel He P.1078 was a single-seat interceptor developed for the Luftwaffe by Heinkel aircraft manufacturing company under the  „Jägernotprogramm“ (Emergency Fighter Programm) during the closing stage of the Third Reich.
Germany’s Emergency Fighter Program was enacted in the middle of July in 1944 in response to the Allied bombing offensive taking out critical German war-making capabilities. The new aircraft was intended to have superior performance in order to deal with the expected high altitude threats such as the Boeing B-29 Superfortress, but only had a 30-minute endurance figure.
The high-altitude fighter designs brought forward by other German aircraft makers were the Messerschmitt Me P.1101, Focke-Wulf Ta 183 „Huckebein“, Blohm & Voss Bv P.212, and Junkers EF 128.
The Heinkel Company was a competitor, too, and offered ist He P.1078 project in three quite different variants. All of them were a single-seat fighters with polyhedral swept wings. The wings were swept back at 40 degrees and included wood in their construction. All of the projected aircraft had the wing tips angled downwards and all of them would be powered by a single Heinkel/Hirth HeS 011 turbojet.
The Heinkel He P.1078A was a turbojet-powered interceptor. It was the most conventional-looking of the three designs submitted for it was the only one having a tail. Its armament was two MK 108 cannons, as in the following two variants.
The Heinkel He P.1078B was a tailles asymmetric jet-powered interceptor with a short fuselage in which the air intake of the engine was located in the middle between two gondolas. The cockpit was located on the gondola of the left side, while the right side gondola contained the front undercarriage leg and cannon armament.
Finally the Heinkel He P.1078C was a tailless interceptor project similar to the He P.1078B but with a single short fuselage. Both the He P.1078B and He P.1078C had wing tips angled downwards at a more pronounced angle than the He P.1078A.
To keep production costs down and expedite mass production, the Heinkel He P.1078C design was relatively simple in nature, utilizing wood wherever possible. The metal fuselage sported a length no longer than 17 feet and contained the armored cockpit, armament and relatively large single engine fitting, fuel was to be housed in the wings. Wingspan was just under 30 feet and the design as a whole just topped 7 feet, 8 inches in height. The armament would have consisted of two MK 108 cannons fitted to either side of the nose section. The nose section itself was rather short and acted as the air intake to aspirate the turbojet engine buried further aft in the design. The opening was rectangular in nature and conformed well to the fuselage’s square appearance when viewed in the forward profile. The engine exhausted at the rear through a conventional exhaust ring. The cockpit was held well-forward in the design with the pilot seated under a small canopy allowing for limited viewing ahead and to the sides (the rear was obstructed by way of a short fuselage spine). The undercarriage was fully retractable and would have consisted of three landing gear legs: two main legs at amidships and a nose landing gear leg – all were single-wheeled installations. When at rest, this arrangement would have given the He P.0178C a distinct “nose-up” appearance, in effect perhaps promoting quicker take-offs with the increased wing drag at speed. Since the turbojet-powered fighter would have been operating at high altitudes, the cockpit was to be fully pressurized and equipped withan ejection seat.
Perhaps the most identifiable portion of the He P.1078Cs design was its wings. The assemblies were fitted high against the fuselage sides and extensively swept rearwards. Each wing was cranked upwards from fuselage centerline up to roughly three-quarters out and then capped with a short wing piece cranked sharply downwards. The reason for this design was largely related to aerodynamic principles that were still being researched at the time and the result was to have combated stress effects on the wings at high speeds. Ernst Heinkel was convinced of their ability to provide for increased maneuvering and agility during dogfights. It bears note that there were no horizontal tailplanes in the Heinkel design and the entire internal fuel load for the thirsty turbojet engine was to be stored across both of the wings. However, the wings were not armored which unduly would have exposed them to enemy fire even of the slightest degree.
After being subject to severe criticism, the project was cancelled by Heinkel at the end of February 1945 (Ref: 17, 22, 24).

Fighter, Projects

Focke-Wulf Fighter Project II (MP-Models)

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TYPE: Fighter, interceptor

ACCOMMODATION: Pilot only

POWER PLANT: One Junkers Jumo 004B turbojet engine, rated at 950 kp thrust

PERFORMANCE: 541 mph at 13,130 ft

COMMENT: The earliest known Focke-Wulf attempt at a single-turbojet fighter, shown in a drawing dated November 1942, the Focke-Wulf Fw 190TL, had involved simply bolting a very basic in-house designed turbojet Fw T.1 to the front of an operational Fw 190.
On January 1943, company aerodynamicist J. C. Rotta offered a report entitled “Fundamentals For The Design of a Turbojet Fighter” which looked at how a large turbojet fighter ought to be, what sort of shape and layout would be best, what turbojet engines could be fitted and how, what the advantages and disadvantages of piston engines and turbojet engines were and what aerodynamic issues were.
To illustrate his points, Rotta came up with a trio of remarkably foresighted designs:

Fighter with turbojet engine BMW 003, P 3302 Design 1,
Fighter with turbojet engine BMW 003, P 3302 Design2, and
Fighter with turbojet engine Junkers Jumo 004.

Each of the three designs had its turbojet engine mounted on its back, just as the Heinkel He 162 would be configured 20 months later. The first and third designs also had forward-swept wings and backward-swept V-tails. The second BMW powered P 3302 design had unswept wings and an unswept V-tail.
However, Focke-Wulf’s design team seem to have completely ignored Rotta’s ideas when they actually started work on a series of single-seat, single-engine turbojet fighters. A report from August 1944 charts the team’s progress through seven different designs.
The first of these, dated March, 1943, was a tail-sitter based on a Fw 190 but with the cockpit relocated to the nose in place of the familiar BMW 801 piston engine, with the turbojet positioned directly below. But with this arrangement no satisfactory rolling properties were to be expected and there was also the risk of burning the airfield surface.
The second design from June, 1943, seems th have been more highly regarded and had its own separate “Baubeschreibung” (Construction description) number, the closest thing Focke-Wulf had to a “P” designation.
The wing was mounted mid-fuselage and had a slight sweep on the leading edge and straight trailing edges, the tailplane was similar to the Fw 190. The design had a tricycle undercarriage and a Junkers Jumo 004B turbojet engine was positioned more centrally under the fuselage. The cockpit was heavily protected by armor of varying thicknesses. Armament was to be two MK 108 (70 rounds each) or MK 103 30mm cannon in the fuselage nose and two MG 151/20 20mm cannon (175 rounds each) in the wing roots.
The main advantage of positioning the turbojet engine under the fuselage was to facilitate maintenance, but there were several bigger disadvantages to this design, such as the nose wheel blocking the intake on take-off and landing, objects being sucked into the air intake since it was so close to the ground. and the damage or destruction of the turbojet engine in case of a belly landing.
Finally, this design was rejected.
As far as the other five different designs are concerned.  Two oft them were basis for the later Focke-Wulf twin-boom Fighter Projekt VIII „Flitzer“ („Streaker“) and  swept-wing, high-mounted tailplane featured Focke-Wulf  interceptor Ta 183 „Huckebein“ (Ref: 17, Uhr, D. and D. Sharp: „Luftwaffe:Secret Projects Profile“, Mortons Media Group Ltd., Horncastle, U.K., 2018).

Nightfighter

Dornier Do 335A-6 (Dragon Models)

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TYPE: Two-seat all weather and night interceptor

ACCOMMODATION: Pilot and radar operator

POWER PLANT: Two Daimler-Benz DB 603A-2, rated at 1,726 hp each

PERFORMANCE: 400 mph at 17,400 ft

COMMENT: The Dornier Do 335 “Pfeil” (“Arrow”) was a WW II heavy fighter built by the Dornier Company. The Do 335s performance was much 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. It was Germany’s Luftwaffe fastest piston-engine aircraft of World War II. The Luftwaffe was desperate to get the design into operational use, but delays in engine deliveries meant that only a handful were delivered before the war ended.
In early 1944 the Do 335 was scheduled to begin mass construction, with the initial order of 120 preproduction aircraft to be manufactured by DWF (Dornier-Werke Friedrichshafen) to be completed no later than March 1946. This number included a number of bombers, destroyers (heavy fighters), and several yet to be developed variants. At the same time, DWM (Dornier-Werke München) was scheduled to build over 2000 Do 335s in various models, due for delivery in March 1946 as well.
While the Dornier Do 335A-0 assembly line at Oberpfaffenhofen was struggling to overcome delays in deliveries of power plants, airscrews, radio equipment and sub-contracted components and assemblies, a number of “Versuchs” (Test) machines for other “Pfeil” subtypes joined the test programme, these including the first two seat models, the Do 335A-6 bad-weather and night interceptor and the Do 335A-12 trainer..
The Dornier Do 335 V10 was the first prototype for the Do 335A-6 radar-equipped two set all weather and night interceptor in which a second cockpit for the radar operator was inserted aft and above the normal cockpit. In order to provide space for the additional cockpit the fuel tankage was drastically revised, the weapon bay being deleted and its space utilized for fuel, fuselage tankage being increased substantially. Cannon armament remained unchanged, but a FuG 101a radio altimeter was
introduced together with FuG 217J-2 “Neptun” intercept radar with wing-mounted antennae. Exhaust flame damping tubes for the fore and aft engines added their measure of drag to that provides by the second cockpit and the radar antennae, and normal loaded weight increased by app. 500 kg. Performance accordingly fell by 10 per cent, but whereas the Do 335 V10 had Daimler-Benz DB 603A-2 engines, the production Do 335 A-6 was intended to have DB 603E engines with provision for methanol-water injection (MW 50) for power boosting below the rated altitude of power plants. Provision was to be made in the wings for two MW 50 tanks, power being boosted to 2,400 hp at sea level per engine.
Production of the Dornier Do 335A-6 night and all-weather fighter had been transferred to the Heinkel factory at Vienna, but despite high priority allocated to the program, circumstances prevented the necessary jigs and tools being assembled (Ref: 7, 12).

Fighter, Fighterbomber

Heinkel He 280 V6 (Huma Models)

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TYPE: Fighter aircraft

ACCOMMODATION: Pilot only

POWER PLANT: Two Junkers Jumo 004B-1 turbojet engines, rated at 900 kp thrust each

PERFORMANCE: 508 mph at 19,685 ft

COMMENT: The Heinkel He 280 was the first turbojet-powered fighter aircraft in the world. It was inspired by Ernst Heinkel‘s’s emphasis on research into high-speed flight and built on the company’s experience with the Heinkel He 178 turbojet prototype. A combination of technical and political factors led to it being passed over in favor of the Messerschmitt Me 262 „Schwalbe“ (Swallow). Only nine were built and none reached operational status
The Heinkel company began the He 280 project on its own initiative after the Heinkel He 178 had been met with indifference from the Reichsluftfahrtministerium (RLM, Reich Aviation Ministry).
Work on the project began under the Heinkel designation „Projekt 1065“ in late 1939 but in March, 1940, after receiving official support the designation Heinkel He 280 was applied. The design had a typical Heinkel fighter fuselage, elliptical wings and a dihedralled tailplane with twin fins and rudders. Power was provided by two Heinkel HeS 8 centrifugal turbojet engines and had a tricycle undercarriage landing gear with very little ground clearance. This arrangement was considered too frail for the grass or dirt airfields of the era; however, the tricycle layout eventually gained acceptance. The He 280 was equipped with a compressed-air powered ejection seat, the first aircraft to carry one and the first aircraft to successfully employ one in an emergency.
The first prototype was completed in the summer of 1940, but the Heinkel HeS 8 intended to power it was running into difficulties. On September 1940, while work on the engine continued, the first prototype started glide tests with ballasted pods hung in place of its engines. It was another six months before the second prototype flew under its own power, on March 1941. The aircraft was then demonstrated to Ernst Udet, head of RLM’s development wing, on April, 1941, but like its predecessor, it apparently failed to make an impression. One benefit of the He 280 which did impress the political leadership was the fact that the jet engines could burn kerosene, which requires much less expense and refining than the high-octane fuel used by piston-engine aircraft. However, government funding was lacking at the critical stage of initial development.
Over the next year, progress was slow due to the ongoing engine problems. A second engine design, the Heinkel HeS30 was also undergoing development, both as an interesting engine in its own right, as well as a potential replacement for the HeS 8. In the meantime, alternative powerplants were considered, including the Argus As 014 pulsejet that powered the Fieseler Fi 103 V-1 Flying bomb. It was proposed that up to eight be used.
Engine problems continued to plague the project. In 1942, the RLM had ordered Heinkel to abandon the HeS 8 and HeS 30 to focus all development on a follow-on engine, the Heinkel/Hirth HeS 011, a more advanced and problematic design. But because the HeS 011 was not expected for some time, Heinkel selected the rival BMW 003. However, this engine also had problems and delays. The second He 280 prototype was re-engined with Junkers Jumo 004  The Jumo 004 engines were much larger and heavier than the HeS 8 that the plane had been designed for, and while it flew well enough on its first powered flights from March 1943, it was clear that this engine was unsuitable. The aircraft was slower and generally less efficient than the Messerschmitt Me 262.
Meanwhile, the He 280 V4 and V5 had been completed, the latter with Heinkel-Hirth 001 turbojets and the former with BMW 003A-0 turbojets. The He 280 V5 was considered by Heinkel tob e representative of he proposed He 280A-1 production standart. Ist claimed peformance include a maimum speed of 509 mph at 19,685 ft at normal loaded weight. The Heinkel He 280 V6 was completed with Junkers Jumo 004 engines and full armament from the onset. Amarment consisted of three 20 mm MG 151 cannon in the fuselage nose and one 500 kg or two 250 kg bombs. The He 280 V6 was tested at Rechlin, and in early 1943, Heinkel tendered a proposal to the Technische Amt for the He 280B-1 fighter bomber with two Junkers Jumo 004 engines and an estimated maximum speed of 547 mph.
By this time, flight testing of the Messerschmitt Me 262 V4 suggested that the Messerschmitt fighter would have a performance advantage over the Heinkel He 280 when fitted with similar power plants, and particularly in so fas as range was concerned, this being a serious defect in the Heinkel fighter’s performance. Thus, on March 1943 the Technische Amt instructed Heinkel to abandon all further development of the He 280 as a fighter, permission being given to complete only the nine prototypes which were allocated to various test programmes (Ref.: 7, 24).