HEINKEL HE-280, FINE UNPRODUCTED NAZI'S JETS

The Heinkel He 280 was the first turbojet-powered fighter aircraft in the world. It was inspired by Ernst Heinkel's emphasis on research into high-speed flight and built on the company's experience with the He 178 jet prototype. A combination of technical and political factors led to it being passed over in favor of the Messerschmitt Me 262.^{[citation needed]} Only nine were built and none reached operational status

Development

The Heinkel company began the He 280 project on its own initiative after the He 178 had been met with indifference from the Reichsluftfahrtministerium ("RLM") (Ger. "Reich Aviation Ministry"). The head designer was Robert Lusser, who began the project under the designation He 180 in late 1939. It had a typical Heinkel fighter fuselage, elliptically-shaped wings and a dihedralled tailplane with twin fins and rudders. The landing gear was of the retractable tricycle type with very little ground clearance.^[2] Internally, the He 280 was equipped with a compressed-air powered ejection seat, the first aircraft to carry one. It was also planned to pressurize the cockpit.^{[citation needed]}

The first prototype was completed in the summer of 1940, but the HeS 8 intended to power it was running into difficulties. On 22 September 1940, while work on the engine continued, the first prototype started glide tests with ballast hung in place of its engines.^[2] It would be another six months before Fritz Schäfer would take the second prototype into the air under its own power, on 30 March 1941. The type was then demonstrated to Ernst Udet, head of RLM's development wing, on 5 April, but like its predecessor, it apparently failed to make an impression.^{[citation needed]}

Had Udet approved development, Heinkel would have received the extra funding which they needed. This might have led to a rectification of the problems they were having with the jet engines. This was the case across all jet engine development in Germany; government funding was lacking at the critical stage that of initial development. The entire jet program was under-funded, with the effect unreliable engines were commonplace.^{[citation needed]}

A contest flight in 1941 comparing an He 280 with a Focke-Wulf Fw 190 had the He 280 completing four laps of an oval course before the Fw 190 could complete three. Ernst Heinkel designed a smaller jet fighter airframe for the He 280 that was well matched to the lower-thrust jet engines available in 1941. The maximum weight of the He 280 was 4,296 kg (9,470 lb), compared to 7,130 kg (15,720 lb) for the Me 262 (which did not get an adequate thrust engine until late 1944). The He 280 could have gone into production by late 1941 and maintained the air superiority which the Fw 190 had established, and filled the gap between the Fw 190 and Me 262. Initial problems with the HeS 8 engine would have likely been ironed out as production of the fighter began.

Some of the resistance to the He 280 would make little sense today. The tricycle landing gear was considered too frail for grass or dirt airfields which were common at the time especially in Russia and North Africa. The Me 262 was originally designed as a tail-dragger, but this configuration makes it difficult for a jet to become airborne. Test pilots had to tap on the brakes to get the Me 262 tail off the ground while trying to take off. Pioneered on its fifth prototype with fixed gear, and made retractable on the sixth prototype and afterwards, the Me 262 emerged with its redesigned tricycle landing gear.

One benefit of the He 280 which impressed 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. The He 280 might have been more easily "sold" if Heinkel stressed the possibility of using it as an attack aircraft for anti-shipping. While the R4M rockets were not available until 1944, the Germans did develop the Nebelwerfer in 1941, which was a 150 mm (5.9 in) artillery rocket launcher. These tubes could have been mounted underneath the wings of a jet. German pilots complained that bombs dropped by the Me 262 had little chance of hitting their targets. A forward-firing recoilless weapon would have been much more effective.

Had the German government given support to production, the He 280s could conceivably have gone into production earlier in the war and reached the Luftwaffe earlier than was ultimately the case with the Me 262. But it was not to be, as Udet, on that April day in 1941, could not see a need for a plane without propellers, no matter what its future might be.^{[citation needed]}

Over the next year, progress was slow due to the ongoing engine problems. A second engine design, the HeS 30 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 famously powered the V-1 flying bomb.^[3] (Using as many as eight was proposed.)^[4]

By the end of 1943, however, the third prototype was fitted with refined versions of the HeS 8 engine and was ready for its next demonstration. On 22 December, a mock dogfight was staged for RLM officials in which the He 280 was matched against an Fw 190. Here, the jet demonstrated its vastly superior speed.^{[citation needed]} Finally, at this point the RLM became interested and placed an order for 20 pre-production test aircraft, to be followed by 300 production machines.

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 HeS 011, a much more advanced (and therefore problematic) design.^{[citation needed]} Meanwhile, the first He 280 prototype had been re-equipped with pulsejets^[5] and was towed aloft to test them. Bad weather caused the aircraft to ice up, however, and before the jets could be tested, pilot Helmut Schenk became the first person to put an ejection seat to use. The seat worked perfectly, but the aircraft was lost, and never found.

With the HeS 011 not expected for some time, Heinkel was forced to accept that it would have to use a competitor's engines, and selected the BMW 003. Unfortunately, this engine was also experiencing problems and delays, and in the meantime, the second He 280 prototype was re-engined with Junkers Jumo 004s while the next three airframes were earmarked for the BMW motor (which, in the end, would never be ready before the end of the He 280 project). The Jumo engines were much larger and heavier than the HeS 8 that the plane had been designed for, and while it flew well enough (for the first time on 16 March 1943), it was immediately obvious that this engine would be unsuitable in the long term.^{[citation needed]} The aircraft was slower and generally less efficient than the Me 262.^[2]

Less than two weeks later, on 27 March, Erhard Milch cancelled the project. The Jumo 004-powered Me 262 appeared to have most of the qualities of the He 280, but was better matched to its engine. Heinkel was ordered to abandon the He 280 and focus attention on bomber development and construction, something he remained bitter about until his death.^{[citation needed]}

Specifications (He 280 V3)

General characteristics

• Crew: 1, pilot
• Length: 10.40 m (34 ft 1 in)
• Wingspan: 12.20 m (40 ft)
• Height: 3.06 m (10 ft)
• Wing area: 21.5 m² (233 ft²)
• Empty weight: 3,215 kg (7,073 lb)
• Loaded weight: 4,280 kg (9,416 lb)
• Max takeoff weight: 4,300 kg (9,470 lb)
• Powerplant: 2× Heinkel HeS.8 turbojet, 5.9 kN (1,320 lbf) each

Performance

• Maximum speed: 820 km/h (512 mph)
• Range: 370 km (230 mi)
• Service ceiling: 10,000 m (32,000 ft)
• Rate of climb: 1,145 m/min (3,756 ft/min)

Armament

• 3 × 20 mm MG 151/20 cannons

(Wiki)

NORTH AMERICAN F-107

The North American F-107 was North American Aviation's (NAA) entry in a United States Air Force tactical fighter-bomber design competition of the 1950s. The F-107 incorporated many innovations and radical design features, and was based on the F-100 Super Sabre. The competition was eventually won by the F-105 Thunderchief, and the F-107 prototypes ended their lives as test aircraft

Design and development

A side-view photograph of the F-107A

In June 1953, North American initiated an in-house study of advanced F-100 designs, leading to proposed interceptor (NAA 211: F-100BI denoting "interceptor") and fighter-bomber (NAA 212: F-100B) variants.^[2] Concentrating on the F-100B, the preliminary engineering and design work focused on a tactical fighter-bomber configuration, featuring a recessed weapons bay under the fuselage and provision for six hardpoints underneath the wings. Single-point refuelling capability was provided while a retractable tailskid was installed. ^[3]An all-moving vertical fin and an automated flight control system was incorporated which permitted the aircraft to roll at supersonic speeds using spoilers.^[4]The flight control system was upgraded by

the addition of pitch and yaw dampers.^[3]

The aircraft's most distinguishing feature is its dorsal-mounted Variable Area Inlet Duct (VAID). While the VAID was a system unique to the F-107A, it was an early form of a variable geometry intake ramp which automatically controlled the amount of air fed to the jet engine.^[5] Although the preliminary design of the air intake was originally located in a chin position under the fuselage (an arrangement later adopted for the F-16), the air intake was eventually mounted in an unconventional position directly above and just behind the cockpit.^[6] The VAID system proved to be very efficient and NAA used the design concept on their A-5, XB-70 aircraft and XF-108 Rapier designs. ^[7]

The air intake was in the unusual dorsal location as the USAF had required the carriage of an underbelly semi-conformal nuclear weapon. The original chin intake caused a shock wave that interfered in launching this weapon. The implications this had for the survivability of the pilot during ejection were troubling. It also severely limited view to the rear. Although this was not considered terribly important for a tactical fighter-bomber aircraft, it is characteristic of the era, when it was assumed air combat would be via guided missile exchanges outside visual range. ^[8]

In August 1954, a contract was signed for three prototypes along with a pre-production order for six additional airframes.^[6]

[edit] Designation and names

Extensive design changes resulted in its redesignation from F-100B to F-107A before the first prototype flew. The F-107 was never given an official name, but was sometimes informally called the "Super Super Sabre"^[9]referring to North American's earlier fighter design, the F-100 Super Sabre.^[10] The flight crews referred to it as the "man eater," in reference to the position of the air intake directly above the cockpit.^[11]

The designation "F-107A" was the only one assigned to the aircraft,^[12][10]though "YF-107A" is often used in publications.^[3][13]

[edit] Operational history

An F-107A in flight

The first F-107A (s/n 55-5118) with North American's chief test pilot Bob Baker at the controls, made its initial flight on 10 September 1956, attaining Mach 1.03.^[14]Although successfully carrying out its flight, the brake chute did not deploy, which resulted in a "hot" landing with the nose gear strut breaking.^[14] The aircraft first achieved Mach 2 in tests on 3 November 1956.

The second F-107A (s/n 55-5119) made its first flight was on 28 November 1956. It was used for weapons testing with both conventional and atomic bombs. The last prototype, (s/n 55-5120) had its maiden flight on 10 December 1956.

At the conclusion of the F-107A's successful test program, the Tactical Air Command decided to hold a fly-off competition between the F-107A and the Republic F-105 which was designed to same mission requirements and used the same engine. Although the competition was close, the F-105 was selected as the new standard TAC tactical fighter. The three F-107A prototypes were relegated to test flying while the pre-production order was cancelled. ^[15]

In late 1957, prototypes #1 and #3 were leased to the National Advisory Committee for Aeronautics (NACA) for high-speed flight research, while aircraft #2 was flown on 25 November 1957 to the National Museum of the United States Air Force near Dayton, Ohio. In September 1959, with Scott Crossfield at the controls, aircraft #3 was damaged during an aborted takeoff. The aircraft was not repaired and, ultimately, it was used for fire fighting training and was destroyed in the early '60s.^[16]

[edit] Survivors

• Aircraft #1 (s/n 55-5118) is currently on display at the Pima Air and Space Museum in Tucson, Arizona.
• Aircraft #2 (s/n 55-5119) is on display in the experimental aircraft hangar at the National Museum of the United States Air Force in Dayton, Ohio. It was delivered to the museum in 1957.^[17]

[edit] Specifications (F-107A)

Data from ^[18]

General characteristics

• Crew: 1
• Length: 61 ft 10 in (18.85 m)
• Wingspan: 36 ft 7 in (11.15 m)
• Height: 19 ft 8 in (5.89 m)
• Wing area: 376 ft² (35 m²)
• Empty weight: 22,696 lb (10,295 kg)
• Loaded weight: 39,755 lb (18,033 kg)
• Max takeoff weight: 41,537 lb (18,841 kg)
• Powerplant: 1× Pratt & Whitney YJ75-P-9 turbojet, 24,500 lbf (109 kN)

Performance

• Maximum speed: Mach 2+
• Range: 2,428 mi (2,109 nmi, 3,885 km)
• Service ceiling: 53,200 ft (16,220 m)
• Rate of climb: 39,900 ft/min (203 m/s)
• Wing loading: 106 lb/ft² (516 kg/m²)
• Thrust/weight: 0.62

Armament

• Bombs: 10,000 lb (4,500 kg)

(WIKIPEDIA)

SAUNDERS-ROE PRINCESS, BRIT'S GIGANTIC SEAPLANE

The Saunders-Roe Princess was a British flying boat aircraft built by Saunders-Roe, based in Cowes on the Isle of Wight. The Princess was one of the largest aircraft in existence.

By the 1950s, large, commercial flying boats were being overshadowed by land-based aircraft. Factors such as runway and airport improvements added to the viability of land-based aircraft, which did not have the weight and drag of the boat hulls on seaplanes nor the issues with seawater corrosion.

Design and development

In 1945, Saunders-Roe was asked by the British Ministry of Supply to bid for a long range civil flying boat for British Overseas Airways Corporation (BOAC), who planned to use them on transatlantic passenger services. Saunders-Roe's bid was successful, and it received an order for three aircraft in May 1946.

The Princess was powered by ten Bristol Proteus turboprop engines, powering six propellers. The four inner propellers were double, contra-rotating propellers driven by a twin version of the Proteus, the Bristol Coupled Proteus; each engine drove one of the propellers. The two outer propellers were single and powered by single engines. The rounded, bulbous, 'double-bubble' pressurized fuselage contained two passenger decks, with room for 105 passengers in great comfort.

The ailerons and rudder were split into multiple sections such that if a part of the servo-powered control system failed the faulty section could be "trailed" so that it did not act against the working sections. The planing bottom of the hull had only a slight step in the keel to minimize drag in the air.

Flight testing

In 1951 BOAC changed its mind about its needs and decided it had no requirement for the Princess. It was announced that construction of the three aircraft would continue as transport aircraft for the RAF. However, in March 1952, it was announced that while the first prototype would be completed, the second and third would be suspended to await more powerful engines. The prototype, G-ALUN, first flew on 22 August 1952 and was flown by test pilot Geoffrey Tyson off the Solent. A planed two-three hour flight was curtailed because of erroneous readings on airscrew bearing temperature. Three more flights followed in that week and then it appeared at Farnborough that year.

G-ALUN was the only one to fly - making 46 test flights in total, about 100 hours flying time. It appeared at the Farnborough Airshow in 1953.

Princess Air Transport Co., Ltd was formed with the object of studying the factors affecting the operation of the Princess flying-boats and to tender for their operation should the opportunity have arisen. The Directors were M. D. N. Wyatt (chairman), Sir Archibald Hope, Mr. G. A. V. Tyson, Mr. P. D. Irons and Capt. H. W. C. Alger (general manager). Three-quarters of the share capital were held by Saunders- Roe, Ltd., and one quarter by Airwork, Ltd.

Termination of production

Two other Princesses (G-ALUO and G-ALUP) were built, but they never flew. After a number of years in mothballs, two at Calshot Spit, awaiting further use, NASA considered using them as heavy-duty freight aircraft for transporting Saturn V rocket components. Aquila Airways offered £1 million pounds each for the Princesses in 1954 The nascent Airbus consortium thought of using two for transporting A300 fuselage sections, but opted to use Super Guppies instead. All three Princesses were broken up in 1967.

They were the last fixed-wing commercial aircraft produced by Saunders-Roe. The company built one more fixed-wing design, the Saunders-Roe SR.53 mixed-power (rocket and turbojet) fighter design; aside from that, the company concentrated on helicopters and hovercraft after this point.

Whilst the prototype aircraft had advanced (but conventional) hydraulic controls, S-R intended production aircraft to use an analogue system based around electrical servos with hydraulic final control actuators. Such a system was built and ground-tested, but the Princess project was cancelled before any aircraft was fitted with the system.

Specifications

Data from British Flying Boats and Flight 1952

General characteristics

• Crew: 2 pilots, 2 flight engineers, radio operator and navigator
• Capacity: 105 passengers in tourist and first class cabins
• Length: 148 ft (42.1 m)
• Wingspan: 219 ft 6 in (66.9 m)
• Height: 55 ft 9 in (17 m)
• Wing area: 5,019 sq ft (466 m²)
• Airfoil: "Saro-modified Goldstein section" to "modified N.A.C.A. 4415 Series" at tip
• Empty weight: 190,000 lb (86,184 kg)
• Loaded weight: 330,000 lb (150,000 kg)
• Max takeoff weight: 345,025 lb (156,500 kg)
• Powerplant: 10× Bristol Proteus 600/610 turboprop, 2,500 shp (2,386 kW) plus 820 lbf (3.66 kN) jet thrust each
• Propellers: 4 bladed De Havilland constant-speed, quick-feathering propellers, 1 (inner pairs contrarotating on common axis) per engine
  • Propeller diameter: 16 ft 6 in (5.03 m)
• *fuel capacity 14,000 Imperial gallons in inner wings

Performance

• Maximum speed: 330 knots (380 miles per hour (610 km/h)) at 37,000 ft (11,300 m)
• Cruise speed: 313 knots (360 miles per hour, 580 km/h) at 32500 ft (9,900 m)
• Stall speed: 98 knots (113 mph, 182 km/h) Flaps down
• Range: 5,720 miles (4,974 NM, 9,205 km)
• Service ceiling: 39,000 ft (11,887 m) Absolute ceiling
• Rate of climb: 1,900 ft/min (579 m/min) at sea level

BRISTOL BRABAZON, BRIT'S GIGANTIC AIRLINER

The Bristol Type 167 Brabazon was a large airliner, designed by the Bristol Aeroplane Company to fly transatlantic routes from the United Kingdom to the United States. The prototype was delivered in 1949, only to prove a commercial failure when airlines felt the plane was too large and expensive to be useful. Despite its size, comparable to a Boeing 767, it was designed to carry only 100 passengers, albeit in roomy conditions not generally found on modern aircraft. In the end, only a single prototype was flown; it was broken up in 1953 for scrap, along with an uncompleted second fuselage

Background

In 1943, a British government committee met under the leadership of Lord Brabazon of Tara to investigate the needs of the British civil airliner market.

The Brabazon Committee delivered a report, known as the "Brabazon Report", calling for the construction of four of five designs they had studied. Type I was a large transatlantic airliner, Type III a smaller airliner for the Empire air routes, and Type IV a jet powered 500 mph (800 km/h) airliner. The Type I and IV were considered to be very important to the industry, notably the jet powered Type IV which would give the UK a commanding lead in jet transports.

Bristol had already studied a large bomber design starting as early as 1937, but nothing had come of this. In 1942 the Air Ministry published a tender for a new super-heavy bomber design, and Bristol dusted off their original work and updated it for their newer and much more powerful Bristol Centaurus engines. This led to a design with a range of 5,000 mi (8,000 km), 225 ft (69 m) wing span, eight engines buried in the wings driving four pusher propeller installations, and enough fuel for transatlantic range. This "100 ton bomber" and designs from the other major manufacturers were in many ways the British analogues to the American Convair B-36. However in expectation of long development times, the Air Ministry later changed their mind and decided to continue development of the Avro Lancaster, (leading to the Avro Lincoln) instead.

Testing

The Mk.I aircraft, registration G-AGPW, rolled out for engine runs in December 1948, and flew for the first time, over Avonmouth for 25 minutes, on 4 September 1949 captained by Bristol Chief Test Pilot Bill Pegg. It flew to about 3,000 ft (910 m) at 160 mph (257 km/h) and landed at 115 mph (185 km/h), throttling back at 50 ft (15 m). Four days later, it was presented at the Farnborough Airshow before starting testing in earnest. It was demonstrated at the 1950 Farborough Airshow with a take-off, clean configuration fly-past and a landing. In June 1950, she visited London's Heathrow Airport, making a number of successful takeoffs and landings, and was demonstrated at the 1951 Paris Air Show. By this point, BOAC had lost any interest in the design, if it ever really had any, and although some interest was shown by BEA on flying the prototype itself, various problems that would be expected of a prototype meant it never received an airworthiness certificate.

Cancellation

By 1952, about £3.4m had been spent on development (£53.4m year in year-2000 pounds) and it showed no signs of being purchased by any airline. In March, the British government announced that work on the second prototype had been postponed. The cancellation of the project was announced by the Minister for Supply (Duncan Sandys) on 17 July 1953 in the Commons saying that it had given all the useful technical knowledge it could but with no interest from civil or the military they had no justification for continuing to spend money on it. About 6 million pounds had been spent and a further 2 would be required for the completion of the Mark II. The buildings and runway had cost a further £6 million.^[4] In October 1953, after 164 flights totalling 382 hours flying time, the first prototype was broken up, along with the uncompleted Mk.II prototype. All that remains are a few parts at the Bristol Industrial Museum and Scotland's Museum of Flight.

Although considered a failure and a white elephant, the record of the Brabazon is not entirely unfavourable. At least half of the large sums spent on the project were put into infrastructure, including the large hangars and runway at Filton. This meant that Bristol was now in an excellent position to continue production of other designs and the hall was used for building the Britannia aircraft. In addition, many of the techniques developed as a part of the Brabazon project were applicable to any aircraft, not just airliners.

Bristol had also won the contract for the "unimportant" Type III aircraft, which they delivered as the Bristol Britannia. Using all of the advancements of the Brabazon meant the Britannia had the best payload fraction of any aircraft up to that point, and it kept that record for a number of years. Although the Britannia was delayed after problems with the Type IV, the de Havilland Comet, it went on to be a workhorse for many airlines into the 1970s. The Britannia is still considered by many^[who?] to be the ultimate propeller driven airliner.^{[citation needed]}

Specifications (Mark I)

Data from Flight

General characteristics

• Crew: 6-12
• Capacity: 100 passengers ^[5]
• Length: 177 ft (54.0 m)
• Wingspan: 230 ft (70 m)
• Height: 50 ft (15 m)
• Wing area: 5,317 ft² (494.0 m²)
• Airfoil: Root T.P.4 (mod) Tip T.P.5
• Empty weight: 145,100 lb (65,820 kg)
• Max takeoff weight: 290,000 lb (130,000 kg)
• Powerplant: 8× Bristol Centaurus radial engines, 2,650 hp (1,860 kW) each
• Propellers: paired contra-rotating 3-bladed Rotol
  • Propeller diameter: 16 ft ()
• Fuel capacity 13,650 Imp gal

Performance

• Maximum speed: 300 mph (260 kn, 480 km/h) at 25,000 ft
• Cruise speed: 250 mph (220 kn, 400 km/h) at 25,000 ft
• Range: 5,500 mi (4,800 nmi, 8,900 km) at 250 mph and 25,000 ft
• Service ceiling: 25,000 ft (7,600 m) at full weight
• Rate of climb: 750 ft/min () at sea level
• Max wing loading: 54 lb/ft² (270 kg/m²)
• Minimum power/mass: 0.073 hp/lb (120 W/kg)

(wikipedia)

About Centaurus Engines

To achieve the necessary reduction in drag and also achieve the design criteria, i.e. non-stop across the Atlantic with 100 passengers, a serious rethink was needed. Bristol had done some initial design work for the aborted Type 159 long-range bomber. This had been a 100 ton bomber with a range up to 5000 miles.

Analysis of the current designs showed that conventional wing mounted engines accounted for 30% of the overall drag, although only 5% was needed for cooling. It became clear to the design team that power plants completely submerged in the wing were thus likely to reduce total drag by 25%, if technically feasible.

The wing would have to be at least as thick as the height of the engine, and coupling several engines side by side to a single airscrew would leave the outer wing free from interference and available for fuel storage. By using this method the larger range required could be easily achieved.

(www.aviationarchive.org.uk)