Frustated Projects

[gekho]

The origin of the Me 264 design came from Messerschmitt's long-range reconnaissance aircraft project, the P.1061, of the late 1930s. A variant on the P.1061 was the P.1062 of which three prototypes were built, with only two "engines" to the P.1061's four, but they were, in fact, the more powerful Daimler-Benz DB 606s, each comprising a pair of DB 601 inverted V-12 engines, themselves derided by Reichsmarschall Hermann Goering as "welded-together engines" in August 1942. In early 1941, six P.1061 prototypes were ordered from Messerschmitt, under the designation Me 264. This was later reduced to three prototypes.

The progress of these projects was initially slow, but after Germany had declared war on the United States, the Reichsluftfahrtministerium (RLM) started a more serious programme for a very long range bomber, with the result that a larger, six-engine aircraft with a greater bomb load was called for. To meet this demand, proposals were put forward for the Junkers Ju 390, Focke-Wulf Ta 400 and a six-engine Messerschmitt Me 264B. As the Junkers Ju 390 could use components already in use for the Ju 290 this design was chosen. The Me 264 was not abandoned however as the Kriegsmarine (German Navy) separately demanded a long-range maritime patrol and attack aircraft to replace the converted Fw 200 Condor in this role. As a result, the two pending prototypes were ordered to be completed as development prototypes for the Me 264A ultra long-range reconnaissance aircraft.

 

[vikingBerserker]

I always loved the way that one looked.

 

[Gnomey]

Reminds me a bit of the B-29.

Good stuff!

 

[gekho]

The Cant z.511 Long Range Cargo Hydroplane was first designed by Fillipo Zappata. The first flight took place in Monfalcone (Trieste, north-eastern Italy) in October 1940. It's first operational start took place in February 1942 (Italian territory). The phase of study for the construction of this huge four-engined, double-floated hydroplane (the largest of its category in the world) started at the end of September 1937, when the technical department of CRDA accepted the order of Compagnia Ala Littoria, who requested a long range hydroplane for mail, cargo and passengers link with Latin America. After two years of hard work, the project manager Filippo Zappata and his team were ready with the first prototype. This aircraft – strong and beautiful, able to carry (in theory) 16 passengers to a destination of more than 5.000 km away, flew in October 1940 giving good impressions in spite of its dimensions and its imperfect engines' setting up (after he had tested some national engines, Zappata asked the High Command the permission to purchase six U.S. Wright Cyclone R-2600A propellers: due to the worsening of the diplomatic relationship between Rome and Washington, his request was not accepted).

The CANT Z.511 was then provided with four Piaggio P.XII RC.35 1500 hp engines, the only ones to guarantee acceptable performances on an aircraft weighing 34 tons. In April 1941, the prototype flew from Monfalcone to Grado (far from theunsafe Yugoslavian border) for other trials. On January 1942, the hydroplane had to be employed on different long range routes, as the war against the United States prevented the civil use of CANT Z.511 in the Atlantic area. The ideas were actually original and unusual. Among the projects taken into consideration, were plans to free fifty Italian soldiers and pilots imprisoned in Jeddah by Arab-English forces; to bomb some Russian ports on the Black Sea (Bathumi and Poti), on the Caspian Sea (Baku), or British bases on the Persian Gulf (Oil ports in Bahrein). Some had the odd idea of a spectacular mission (taking off from Bordeaux and twice supplying from German supply-submarines) in the skies of New York, launching one ton of tri-coloured leaflets. Some others thought about a non-stop Rome-Buenos Aires raid (8000 km!). None of these projects were carried out. And it was a real pity, since the test pilot, Mario Stoppani succeeded in taking off and landing fully loaded in very rough seas and 1.5 meter high waves with winds blowing at 55-65 kph during the last trials at the end of February – beginning of March 1942,

 

[Airframes]

Good stuff, and some rather advanced-looking types for the period.

 

[vikingBerserker]

Nice!!

 

[gekho]

The Heinkel He 100 story starts in 1933 with the Reichsluftsfahrtministerium (Reich Air Ministry, or RLM) competition to produce the first modern fighter for the re-forming Luftwaffe. Four designs were submitted; Arado's Ar 80, Focke–Wulf's Fw 159, Heinkel's He 112 and the Messerschmitt Bf 109. All four planes were tested competitively in early 1936 with interim engines, and the Ar 80 and Fw 159 were quickly eliminated. Both the 112 and 109 were considered worthy of further testing, and orders were sent out for 15 additional aircraft from both companies. Although Heinkel was considered the favorite to win the contract, the more modern and better performing 109 won over the Flight Acceptance Commission. By late March of 1936 the 109 was considered the favorite. At that point Heinkel was allowed to redesign the 112, which resulted in the largely all–new 112B. The 112B was considerably improved and was as good or better than the 109, but the 109 won anyway.

The 112 had a few problems that lost it the competition. The first was that the airframe was rather complex; it included a large number of compound curves and its elliptical wing was labor intensive. The RLM was looking to produced hundreds of planes, so cost in both dollars and manhours was a factor. The prototypes also suffered from a series of accidents, even if they weren't related to problems with the plane they still left a bad taste in the mouth. But the biggest problem for the 112 was that after learning that Supermarine had started series production of the Spitfire, the Luftwaffe was desperate to get a modern fighter into squadron hands. Heinkel might have won the competition had the B model been available in early 1936, but by the time they were ready in the second half of the year the 109 was already in series production.

Nevertheless some small scale contracts for the plane were finally secured with a variety of air forces in Europe and Japan. Thirty were bought by Japan, but twelve of these were used briefly by the Luftwaffe during the Sudetenland Crisis. Another nineteen were then sold to Spain where they served long careers. Thirty were sold to Romania, they served in combat in 1941 but were quickly worn out. Finally three more B's were sold to Hungary as the vanguard of a license production series that never took place. By 1939 production of the He 112 ended, and it appeared that Heinkel was out of the fighter business.

Even by early 1936 the RLM became interested in a new fighter that would leap beyond the performance of the Bf 109 as much as the 109 had over the biplanes it replaced. There was never an official project on the part of the RLM, but Roluf Lucht felt that new designs were important enough to ask both Focke–Wulf and Heinkel to provide "super–pursuit" designs for evaluation. Since the super–pursuit type was not an official recommendation, it was possible that Heinkel would be told to stop work on the project. Thus the work was kept secret, in a company Memo No.3657 on January 31st this was made clear; "The mockup is to be completed by us... as of the beginning of May... and be ready to present to the RLM... and prior to that no one at the RLMis to know of the existence of the mockup."

Walter Günter —one of Heinkel's most talented designers— looked at the 112 and decided that nothing more could be done with it. He started over with a completely new design known as "Projekt 1035". Learning from past mistakes on the 112 project, the design was to be as easy to build as possible while still offering good performance. That good performance was set at an astounding 700km/h (435mph). Keep in mind that fighters with this sort of performance didn't appear on the battlefield until 1944. To ease production the new design had considerably fewer parts than the 112, and those that remained contained considerably few compound curves. In part count the 100 was made of 969 unique parts and was held together with 11543 rivets, in comparison the 112 had 2885 parts and 26864 rivets. The new straight-edged wing was a source of much of the savings, after building the first wings Otto Butter reported that the reduction in complexity and rivet count (along with the Butter brothers's own explosive rivet system) saved an astonishing 1150 man hours per wing.

In order to get the promised performance out of the plane, the design included a number of drag reducing features. On the simple end was a well–faired cockpit, the absence of struts and other draggy supports on the tail, and fully retractable gear (including the tailwheel) which were completely enclosed in flight. These and similar changes applied to the 109 for the F model would boost performance of that plane 50km/h. The engine was mounted directly to a strong forward fuselage as opposed to internal struts, so the cowling was very tight fitting and as a result the plane has something of a slab sided appearance. The design used a shorter wing than the 109, trading altitude and turn performance for speed. In order to provide as much power as possible from the DB 601 engine, the 100 used exhaust ejectors for a small amount of additional thrust. In addition the supercharger inlet was moved from the normal position on the side of the cowling to a location in the leading edge of the left wing, where the clean airflow improved the ram-air effect and increased boost.

For the rest of the designed performance increase, Walter turned to the risky method of cooling the engine via surface evaporation. Inside the engine the fluid is kept under pressure which stops it from boiling even though it's allowed to heat above its normal boiling point, the fluid is then run to cavity with lower pressure where it quickly starts to boil and releases steam. Since steam contains considerably more energy than the same temperature water, if you can remove the steam you can remove a lot of heat. The stream can be cooled by allowing it to condense in a series of pipes inside the plane. With no external openings at all, it's basically a zero-drag cooling system. On the down side the system is complex and hard to maintain. Worse, it greatly increases the chance of killing the engine in combat due to a "radiator hit" on the now much larger cooling system. Other designs would attempt to use the same sort of design, but invariably returned to conventional radiators due to the complexity. A number of people had already tried the system and given up on it, but Heinkel had good experiences with it on their He 119 high speed bomber project and decided to press ahead.

In the Heinkel system —designed by Jahn and Jahnke— the engine was run at 110 Celsius and the superheated fluid was then sprayed into the interior of a centrifugal compressor, allowing the pressure to drop and steam to form. The water, being heavier, was forced to the outside of the pump by centrifugal force and returned to the engine. The weight of the water forced the steam into the only available space, the inside of the pump, where it was removed. The steam was then allowed to flow into a series of tubes running on the inside surface of the leading edges of the wings, where it would condense back into water and be pumped back to the engine. A number of pumping systems were tried, and eventually a system of no less than 22 small electric pumps (all with their own failure indicator lamp in the cockpit) was settled on.

 

[gekho]

Unlike the cooling fluid, oil cannot be allowed to boil. This presents a particular problem with the DB 601 series of engines, because of a particular design technique that results in a considerable amount of heat being transfered to the oil as opposed to the coolant. To cool the oil a small semi-retractible radiator was fitted under the wing. This radiator was later replaced on some of the prototypes with a system in which the oil was sent to a heat exchanger where it boiled methyl alcohol to carry away the heat. The alcohol was then cooled in a similar fashion to the engine fluid, by running it to tubes on the top surface of the rear fuselage and leading edge of the vertical stabilizer. Walter was killed in a car accident on May 25th, 1937, and the design work was taken over by his twin brother Siegfried, who finished the final draft of the design later that year. The wing started out flat and then bent upwards about 1/3rd along the span, and the portions inboard of the bend were thicker to hold the wheels. The gear retracted inward and thus were wide set when opened, resulting in a significant improvement in ground handling over the 109. The rear of the fuselage sloped down to the tail from a point at about eye level at the rear of the cockpit, so while it didn't have the visibility of the 112's bubble, it was still significantly better than the 109. A small retractable radiator was added for running on the ground where the surface cooling system wouldn't work. The plane was small, slightly smaller than the 112 that spawned it, and considerably lighter.

At the end of October the design was submitted to the RLM, complete with details on prototypes, delivery dates, and prices for three planes delivered to the Rechlin test center. At this point the plane was being referred to as the He 113, but the "13" in the name was apparently enough to prompt Ernst Heinkel to ask for it to be changed to the He 100 (even though it had previously been given to Feiseler). In November Messerschmitt took the speed record for landplanes in a modified 109. In response Ernst Heinkel made plans to use the He 100 design as a record setting plane (less serious plans for this appear to have been in the works all along). Much of the fuselage was as smooth as it could get, so the modifications were limited to the canopy and a newer set of much shorter wings. The racing version would need another airframe, so a fourth prototype was added to the series. In a December meeting at the Heinkel factory with Ernst Udet and Roluf Lucht the plans were changed slightly. V1 through V3 were to be used for testing and record attempts, V3 sporting the clipped wings. V4 was to a testbed for series production. The RLM went ahead with the plan, due in no small part to Udet's (Generalluftzeugmeister, Minister for Aircraft Production in the RLM) plans to fly the plane in a series of record attempts.

Throughout the prototype period the various models were given series designations (as noted above), and presented to the RLM as the basis for series production. The Luftwaffe never took them up on the offer. Heinkel had decided to build a total of 25 of the planes one way or the other, so with 10 down there were another 15 of the latest model to go. In keeping with general practice, any series production is started with a limited run of "zero-series" machines, and this resulted in the He 100D-0. The D-0 was similar to the earlier C models, with a few notable changes. Primary among these was a larger vertical tail in order to finally solve the stability issues. In addition the cockpit and canopy were slightly redesigned, with the pilot sitting high in a large canopy with excellent vision in all directions. The armament was reduced from the C model to one 20mm MG/FF-M in the engine V firing through the propeller spinner, and two 7.92mm MG17's in the wings close to the fuselage. The three D-0 planes were completed by the summer of 1939 and stayed at the Heinkel Marienehe plant for testing.

The final evolution of the short He 100 history is the D-1 model. As the name suggests the design was supposed to be very similar to the pre-production D-0's, the main planned change was to enlarge the horizontal stabilizer. But the big change was the eventual abandonment of the surface cooling system, which proved to be too complex and failure prone. Instead an even larger version of the retractable radiator was installed, and this appeared to completely cure the problems. The radiator was inserted in a "plug" below the cockpit, and as a result the wings were widened slightly. While the plane didn't match it's design goal of 700km/h once it was loaded down with weapons, the larger canopy and the radiator, it was still capable of speeds in the 400mph range. A low drag airframe is good for both speed and range, and as a result the He 100 had a combat radius between 900 and 1000km compared to the 109's 600km. While not in the same league as the later escort fighters, this was at the time a superb range and may have offset the need for the 110 to some degree. By this point the war was underway, and as the Luftwaffe would not purchase the plane in its current form, the production line was shut down.

 

[gekho]

On 22 November 1941, the Army Air Corps signed the development contract for an XB-35; the contract included an option for a second aircraft, which was exercised on 2 January 1942. The first was to be delivered in November 1943, the second in April of the next year. Detailed engineering began in early 1942. A fuselage-like crew cabin was to be embedded inside the wing; it included a tail cone protruding from the trailing edge. This tail cone would contain the remote sighting stations for the gunners in the production model. In the rear of the cabin, there were folding bunks for off-duty crew on long missions. The aircraft's bombload was to be carried in six small bomb bays, three in each wing. This design precluded the carrying of large bombs, including early atomic bombs. Production aircraft would have defensive armament of 20 .5 in (12.7 mm) machine guns or 20 mm cannon, carried in seven turrets, three on the aircraft's centreline and four above and below the outer wings. The B-35 would take advantage of a new aluminium alloy devised by Alcoa; it was considerably stronger than any alloy used previously.

In June 1946, the XB-35 made her first flight, a 45-minute trip from Hawthorne, California to Muroc Dry Lake, with no problems. The XB-35's engines and propellers were Army Air Force property, and had not been tested for engine-propeller Compatibility by either Pratt Whitney, Hamilton Standard, or by the AAF which bought them at Wright Field without testing them or assuring reliability, and then shipped them to Northrop. Microfilmed records of reports and correspondence of the XB-35 program relate that after three or four flights powerplant-propeller vibrations increased, and the very efficient countra-rotating propellers began failing with frustrating frequency. Meetings were called by Northrop, of the AAF, Pratt Whitney and Hamilton Standard where no one would take responsibility for correcting the AAF's engines and propellers. In addition the AAF failed to supply the AC electrical alternator, insisting on Northrop using an automotive engine powered unit which limited the high-altitude, high-speed XB-35 to test flights below 15,000 feet. The AAF also refused to allow Northrop proposed modification of the bomb bays to carry the standard Mk 3 atomic bomb, while at the same time declaring the AF would not buy the bomber unless it could carry the A-bomb. Northrop reluctantly agreed to try a single-rotation propeller which slightly increased takeoff distance and reduced rate of climb and maximum speed.

Problems with the driveline continued until finally Jack Northrop himself grounded the XB-35s until the government would fix their propulsion system. Concurrently, the AAF ordered Northrop to modify two of the YB-35 airframes into YB-49s, essentially just substituting eight jet engines in place of four reciprocating engines, and the airframe promptly flew to more than 40,000 feet and topped 520 mph in flight tests, verifying the XB-35 airframe's aerodynamics, but at the price of range. The prop-version had a design range capable of reaching targets 4,000-miles away, but the jet-engine version's range was cut in half. The new version disqualified it for the Air Force's top priority mission as a strategic bomber, which at that time meant striking at the USSR's industrial and military complexes in the Ural Mountains. The Air Force, itself involved in a confusion of rank and job changes, eventually cancelled the XB-35 project, while continuing testing the B-35 airframe in the YB-49, even ordering 30 of the jet-powered airframes after the first YB -49 crashed. The first and second XB-35s were scrapped on 23 and 19 August 1949, respectively.

 

[vikingBerserker]

Interesting read on the B-35

 

[Gnomey]

Good stuff!

 

[gekho]

The Fairey Spearfish was a 1940s British torpedo bomber designed and built by Fairey Aviation for the Fleet Air Arm. It was one of the largest single-engine aircraft to ever operate from a British aircraft carrier. The Spearfish was designed by Fairey Aviation to Admiralty Specification O.5/43. Having learned the lessons of the Barracuda, the Spearfish had a much more powerful engine and an integral ASV anti-submarine radar (the external installation on the Barracuda caused problems with longitudinal stability). Problems with the Bristol Centaurus engine delayed the first flight until 5 July 1945.

Only five aircraft were built before victory over Japan in August. After the end of the war and the proposal for a more advanced turboprop anti-submarine aircraft (which became the Gannet), further work on the project was stopped and an order for 152 production aircraft cancelled. The Admiralty refused to accept the Spearfish for service use. The aircraft had such heavy controls that in bad weather a pilot circling a carrier while waiting to land was forced to fly such a wide circuit that he could not keep the carrier in sight.

 

[Gnomey]

Nice shots!

 

[vikingBerserker]

Wow, that must have been like trying to fly a bus.

 

[gekho]

The Atlantic Aircraft Corporation of Teterboro, New Jersey was the American subsidiary of the Holland-based Fokker aircraft manufacturing company. It manufactured some Fokker-designed commercial airliners in the United States. Among these were Fokker's series of pioneering high-winged monoplane airliners. Atlantic submitted a monoplane design in response to a 1927 Army competition for a successor to the Martin-designed NBS-1 bomber. A single prototype was ordered under the designation XLB-2. The serial number was 26-210. The XLB-2 was developed from the Fokker series of monoplane transports, and had the distinction of being the first USAAC bomber designed as a monoplane. It was powered by a pair of 410hp Pratt Whitney R-1340 Wasp radials suspended underneath the high cantilever wing. A crew of five was carried. The bombardier position was housed inside a glazed area in the lower nose. A pair of 0.5-inch machine guns were mounted in each of two open defensive gunner positions, one situated in the extreme nose and the other in a dorsal position on the upper rear fuselage. A single gun could be fired through a position in the lower rear fuselage. A 2050 pound load of bombs could be carried. The aircraft was later fitted with a pair of 525 hp R-1690-1 radials, which raised the maximum speed from 116 mph to 123 mph. However, the performance of the XLB-2 was not much better than that of existing Army biplane bombers. In addition, the Army was quite reluctant to consider such radical innovations as cantilever monoplane designs, and the XLB-2 was not ordered into production.

 

[gekho]

Just one week before the outbreak of World War II, Germany flew the world's first jet aircraft. That plane was the Heinkel He-178 which, had its development been pushed, might have altered the course of history. The first successful flights of the world's first turbojet-propelled airplane took place over a German forest on August 24 and 27, 1939, with Luftwaffe Captain Erich Warsitz at the controls. The tiny Heinkel HeS38 jet engine that powered the He-178 produced only 838 pounds of static thrust. But that was enough to push small single-seat monoplane to a speed of well over 400 miles per hour. Thus, even in its earliest test flights this remarkable aircraft demonstrated performance superior to that of many operational fighters.

The Heinkel jet engine was the brainchild of a brilliant young German scientist named Pabst von Ohain, who was only 25 years old when the He-178 made aviation history. The aircraft itself was designed by Heinkel engineers, working under the personal direction of Ernst Heinkel, head of the Heinkel aircraft manufacturing company. That firm financed the development of the He-178 without either the knowledge or financial support of the Nazi government. The 4,400-pound Heinkel He-178 was literally built around the Ohain engine. It had a barrel shaped 24½-foot-long metal fuselage,with stubby 23½-foot wooden wings mounted high on its sides. The aircraft utilized the conventional three-point retractable landing gear, rather than tricycle configuration which was later adopted for other jets.

Despite the He-178's spectacular performance, the German Air Force at first showed scant interest in the plane. It wasn't until October 1939 that high-ranking air force officers agreed to inspect it, and although the He-178 clearly had great potential, it was never produced in quantity. Slow to push development work, the German Air Force didn't have an operational jet fighter plane until August 1944, too late to have a decisive effect on the outcome of World War II. Nevertheless. through the foresight of Ernst Heinkel and the brilliant engineering of Pabst von Ohain, the He-178 ushered in the jet age.

 

[gekho]

The Republic XP-72 was an American prototype interceptor fighter developed as a progression of the P-47 Thunderbolt design. The XP-72 was designed around the Pratt Whitney R-4360 twenty-eight cylinder radial air-cooled engine with a supercharger mounted behind the pilot and driven by an extension shaft from the engine. The armament consisted of six 0.5 in wing-mounted machine guns and underwing racks for two 1,000 lb bombs. The XP-72 development paralleled that of another Republic design, the XP-69 that was to be powered by an experimental forty-two cylinder Wright R-2160 radial engine mounted behind the pilot and driving contra-rotating propellers through an extension shaft. The XP-69 was intended for high altitude operations and featured a pressurized cockpit and armament of two 37 mm cannon and four 0.5 in machine guns. As the XP-72 displayed greater promise than the XP-69, the XP-69 was canceled on 11 May 1943 and an order for two XP-72 prototypes was placed on 18 June 1943.

The XP-72 flew for the first time on 2 February 1944, equipped with a four-bladed propeller. The second prototype was completed on 26 June 1944 and was equipped with an Aero-Products contra-rotating propeller. As the XP-72 displayed exceptional performance during flight tests an order for 100 production aircraft was awarded. The order included an alternate armament configuration of four 37 mm cannon. By this time the war had progressed to where the need was for long-range escort fighters and not high-speed interceptors. Also, the advent of the new turbojet-powered interceptors showed greater promise for the interceptor role. Thus, the production order for the P-72 was cancelled.

 

[gekho]

Two prototypes were created by attaching an extra pair of inner-wing segments onto the wings of basic Ju 90 and Ju 290 airframes, and adding new sections to lengthen the fuselages. The first prototype, the V1, (bearing Stammkennzeichen code of GH+UK), was modified from a Junkers Ju 90V6 airframe (werke number J4918, civil registration D-AOKD) from July 1940 to April 1941, then to the Luftwaffe as KH+XC, from April 1941 through April 1942, then returned to Junkers and used for Ju 390 V1 construction). It made its maiden flight on 20 October 1943 and performed well, resulting in an order for 26 aircraft, to be designated Ju 390 A-1. None of these were actually built by the time that the project was cancelled (along with Ju 290 production) in mid-1944.

The second prototype, the V2 (RC+DA), was longer than the V1 because it was constructed from a Ju 290 airframe (using the fuselage of Ju 290A1 werke number J900155). The maritime reconnaissance and long-range bomber versions were to be designated the Ju 390 B and Ju 390 C, respectively. It has been suggested that the bomber could have carried the Messerschmitt Me 328 parasite fighter for self-defense, and some test flights are believed to have been performed by a Ju 390 prototype equipped with the anti-shipping PC 1400 Fritz X guided glide bomb.

 

[gekho]

The Curtiss XP-62 was the final propeller-driven fighter built by its manufacturer and the second largest single-seat fighter of orthodox layout developed during World War II, its dimensions being exceeded only by the Boeing XF8B naval fighter. The XP-62 was ordered by the USAAF on 27 June 1941 as a vehicle for the 1715kW Wright R-3350 radial engine. Initial plans called for delivery of one XP-62 and one XP-62A and later for 100 production P-62 fighters, but it was clear almost from the beginning that the design was overweight, underpowered, and an uneconomical alternative to continued Curtiss production of the P-47G Thunderbolt. Because it would be an effective testbed for dual-rotation propellers and a pressurized cabin, it was decided on 18 July 1942 to proceed with a sole airframe, the remaining machines on order being cancelled.

Development of the XP-62's cabin pressurisation system was delayed and the aircraft did not fly until early 1944. By then even the XP-62's value as a test ship was marginal and the programme was terminated after a few hours' flying time. Though the unbuilt XP-71 and the jet XF-87 still lay ahead, the great days of Curtiss as a leading fighter manufacturer were now to become history.

 

[vikingBerserker]

Great info!