So, it's been a while since I did anything on this thread but I thought I'd continue while I'm on a semester break. We left the Musee at the Hall of the Cocarde and now we are in the Hall des Voilures Tournantes and start with the Pescara rotorcraft in the entrance. Firstly, Argentina-born Raul Pateras Pescara was something of a polymath and was trained as an engineer and a lawyer whilst conceiving a variety of aircraft designs not limited to rotorcraft. Before the Great War, he dabbled in the design of a torpedo-carrying seaplane of basic design, attempting to convince the Italian Naval Ministry of the feasibility of the concept and it was Capt Guidoni of the Italian Navy that carried lead weights in a canoe-shaped fairing that was dropped from a modified Farman seaplane in 1914, but the Farman was not powerful enough to carry a full-size torpedo aloft. On 26 February 1914, the Pescara-Guidoni PP twin float monoplane seaplane fitted with hydrovanes on its floats lifted an 875 lb dummy torpedo into the air and dropped it; this is recognised as the first airdropping of a torpedo from an aircraft, despite the torpedo being a dummy. Pescara's next aerial venture was rotorcraft and although by the time he began investigating them, the first helicopter had flown - Paul Cornu's pioneering rotorcraft first got airborne in 1907 - existing designs, such as those of his rival Étienne Oehmichen were, although more sophisticated were driven by secondary rotor blades for forward motion. Pescara's rotorcraft had no secondary means of propulsion except the main rotors. Pescara's rotorcraft in the Hall des Voilures Tournantes showing its contra-rotating biplane rotors.
Musee de l'Air 111
Evidently, Pescara got around as his first helicopter was built in Barcelona, Spain in 1919, being completed in 1920, but powered by a 45 hp Hispano Suiza engine was not capable of lifting itself off the ground. Moving to Paris, France he received government funding from Service Technique de I'Aeronautique
and his No.2 was capable of hovering about 1 and a half metres above the ground for short periods of time in 1922. His No.3 (named the No.2F in France) however was the breakthrough aircraft; powered by a 180 hp Hisso vee eight engine cooled by a Lamblin radiator mounted vertically in its tail, its rotors were biplane blades that were capable of warping in flight to alter their pitch, which enabled the coaxial rotors to achieve lift and thrust. In January 1924 named
The Marquis Pateras the No.3 achieved a record for rotor-wing craft by remaining in the air for 8 minutes and 13 seconds. Pescara's machine became the first rotorcraft to achieve a 1-kilometre closed circuit, which Pescara achieved in a time of 10 minutes and 33 seconds, but his attempt at the Grand Prix was disqualified as the aircraft hit the ground and sustained damage during the flight. After further distance and height records achieved by the No.3, Pescara lost interest in his new toy and he returned to Spain and went into automobile manufacturing. The Pescara aircraft in the Hall des Voilures Tournantes is unusual as it has the features of the No.3 but with a radial engine and devoid of the Lamblin radiator in its tail, but its rotor layout is the same. The museum's website doesn't identify the type, other than stating it's a Pescara design. Close up of the radial engine and rotor stem.
Musee de l'Air 112
From an elevated position, the rotor layout can be appreciated.
Musee de l'Air 113
This bizarre contraption was built by Pescara's rival Étienne Oehmichen, whose rotorcraft designs appeared at around the same time as Pescara's but were larger and less practical, relying on four main rotors unable to be actuated, for lift, and a series of wooden propellers mounted at different locations and plains around the crucifix framework that made up the body of his aircraft, for thrust. Like Pescara, Oehmichen was a capable individual who trained as a biologist but was also an inventor, who built a camera capable of shooting 1,000 frames per second. Beginning at around the same time as Pescara, Oehmichen's first helicopter first hovered in 1921 but his No.2, first flying in 1922 was the first reliable rotorcraft, and owing to its fixed-pitch rotors, the small propellers led to the development of the tail rotor as a means of steering the aircraft, which is universally applied to helicopters today. This device, Oehmichen's No.6 was, strictly speaking not a helicopter, but a steerable balloon with take-off and landing lift augmented by four upward-facing propellers he called a Hélicostat. Built in 1931, it was designed to be able to operate without ground crew, which lighter-than-aircraft relied on in numbers back then, so the theory went, although Oehmichen tested it inside the big airship shed at Orly it never saw practical flight. It was donated to the museum in February 1936.
DSC_0313
This next rotorcraft is as bizarre a concept as the Hélicostat, but was applied successfully in its original designed role, that of observation. The Focke-Achgelis Fa 330A-0 Bachstelze (Water Wagtail) was an unpowered rotor kite carried by U boats. Here's a comprehensive description from the Smithsonian National Air and Space Museum: "The navy asked Focke-Achgelis GmbH to build a rotor kite that a U-boat could tow aloft to search for targets. The aircraft had to fly high enough to substantially boost the scouting range, yet remain small, easy to store, and mechanically simple to maintain and operate. Focke-Achgelis proposed a clever design best characterized by simplicity. The Fa 330 was simple to fabricate, easy to assemble on deck for flight, and weighed so little that two men could comfortably hoist the entire machine. The Fa 330 needed no engine because the submarine towed the gyro kite through the air. Like a gyroplane, the rotor kite flew by autorotation, meaning that the movement of relative wind through the rotors caused them to turn with sufficient speed to generate lift.
The airframe consisted of two 6.35 cm (2.5 in) diameter steel tubes joined to form an inverted 'T.' One tube served as the fuselage of the aircraft, which mounted the pilot's seat and rear control surfaces. The other tube served as the rotor mast. A control stick hung from the blade hub atop the mast. The pilot moved the stick for direct (no intervening control linkage) pitch and roll control, and he used foot pedals to move the large rudder and control yaw. The horizontal stabilizer had no moving control surfaces. Weight was saved on the rotor hub by using steel cables to support the blades against blade droop when the aircraft was not flying. The cables also limited the blades' range of movement when during flight. Instrumentation consisted of an altimeter, airspeed indicator, and tachometer. Its landing gear consisted of two small skids.
The three-bladed rotor turned freely but was limited to 250 rpm. This limit was reached if the aircraft attained a never-exceed speed of 80 kph (50 mph). Normal flight rpm was about 205 at a standard towing airspeed of 40 km/h (25 mph). A minimum speed of 27 kph (17 mph) was required to maintain autorotation. Blade pitch could only be set before flight by turning adjustment screws. The blades used flapping and dragging hinges equipped with variable dampers. The rotor blades consisted of a 3.2 m (10 ft 4 in) steel spar that supported plywood ribs. The blades were 0.3 m (12 in) wide and skinned with fabric-covered plywood. The blade airfoil was almost symmetrical. The blades were precisely balanced during the manufacturing process, which eliminated the need for difficult and time-consuming manual balancing at sea.
The Fa-330 was stowed in two tubes of approximately 3.75 meters (12 ft 4in) length built vertically into the U-boat's conning tower. One tube contained the blades and tail and the other contained the fuselage. Four crewmen could assemble the entire structure in three minutes in calm conditions. Rotation of the blades in preparation for flight could be done by hand, but if a course pitch (which provided the best operating performance) was preset on the rotor blades this became extremely difficult. In that case, a rope wrapped around the drum on the rotor hub was used to get the rotor turning. The Fa 330 took off from a small platform attached to the aft railing of the U-boat's conning tower. A towline extended from an electric winch to a quick release coupling on the Fa 330. Since the primary duty of the Fa 330 was to spot suitable targets, communication with the towing vessel was essential. The pilot used an interphone system that consisted of a telephone cable, which paralleled the towline. Upon landing a rotor brake was provided to quickly stop the rotor spinning. Disassembly time was not much greater than that required for assembly. If the U-boat came under attack and had to make a crash dive the pilot could pull a quick-release lever above the seat, and the towline would separate from the aircraft in addition to releasing the rotor hub from the mast. As the rotors departed they pulled a line out, which deployed a parachute. Once the parachute opened, the pilot released his seat buckle, which allowed the remainder of the aircraft structure to fall away. Additionally, the towline quick-release coupling could be manually operated without engaging the rotor release."
This example, Wk Nr 100150 served aboard U 196 and was recovered in Bordeaux and tested by the French navy in the wind tunnel at Chalaix-Meudon in July 1945. Elements from two other Bachstelzes were used in its restoration.
Musee de l'Air 116
This particular autogyro is quite famous when on 18 September 1928 it became the first rotorcraft to fly internationally when it crossed the English Channel and arrived in France. The only Avro built Cierva C.8L Mk.II, this aircraft is based on the fuselage and engine of the Avro 504N two-seat trainer powered by a 180 hp Armstrong Siddeley Lynx IV and received the Avro type designation Type 611 and the civil registration G-EBYY. Built in 1928, the C.8L Mk.II was ordered by Air Commodore James 'Jimmy' Weir, Scottish industrialist and financial backer and chairman of the Cierva Autogiro Company, which, devoid of facilities of its own contracted the construction of aircraft fitted with Juan de la Cierva's rotor technology to different aircraft firms, including Avro. Front view of G-EBYY.
Musee de l'Air 117
Test flown by famed Australian aviator Bert Hinkler at Hamble, it took part in the King's Cup Air Race at Hendon on 20 July but it was forced to retire after a forced landing due to fuel shortage. In August, test pilot A. H. Rawson flew it on a 3,000-mile tour of principal airports around the UK, stopping at Jimmy Weir's estate at Dalrymple, near Turnhouse, Edinburgh. During its successful Channel crossing, it was flown by Cierva himself with French journalist Henri Bouché of the magazine
La Aéronautique as a passenger, from Croydon to Le Bourget, making stops at Saint-Ingelvert and Abbeville. After service in various individual hands in France, it remarkably survived World War Two and was exhibited in the museum sometime after the war.
Musee de l'Air 118
This next autogyro is the SNCASE C.302 and was built under licence following experience building Cierva C.30s by Lioré et Olivier (LeO) in 1931. Nationalised as a part of SNCASE in 1937, LeO manufactured around 100 C.30s and 120 of the French specific C.301 powered by a 175 hp Salmson 9 nine-cylinder engine as opposed to the Armstrong Siddeley engine in the C.30. Four LeO C.30s went to Groupe Aérien d'Observation 504 at Chartres in 1937 as the French military's first rotorcraft but were not fully operational at the time of the German invasion in May 1940 as there could not be found a practical use for them. Built from salvaged parts, two C.302s were cobbled together by SNCASE after World War Two and were similar to the C.301 apart from an altered rotor head, which enabled the rotor to be driven by the engine for what was known as a jumping start, a near-vertical take-off, although after take-off the rotor was disengaged from the engine drive shaft. This one, F-BDAD was the second built and was formerly a part of an aero club at the SNCASE airfield at Marignane before coming to the museum. It's seen here with Channel crossing Cierva C.8L Mk.II G-EBYY for comparison.
Musee de l'Air 119
This Piasecki HUP-2 Retriever represents one of 15 operated by the Aeronavale between 1953 and 1965, although it is an ex-US Navy example gifted to the museum and decorated in the markings of No.130086 of Escadrille 23S at Saint-Mandrier in 1954, the unit being the first in the Aeronavale to operate helicopters. The Aeronavale Retrievers were primarily used for plane guard and utility duties aboard the French aircraft carriers of the LaFayette Class, the former USS Langley as LaFayette and USS Belleau Wood as Bois Belleau, and the Colossus Class Carrier Arromanches, formerly HMS Colossus.
Musee de l'Air 120
A ubiquitous Bell 47, construction number 710, F-MBCV.
Musee de l'Air 121
Finally for today, this is the SNCASO SO.1220 Djinn, the first helicopter powered by a gas turbine that drove rotor tip jets. Powered by a single Turboméca Palouste 4, this is the second prototype of the production SO.1221 Djinn; wiki describes the use of the tip jets in detail: "The Sud-Ouest Djinn was the first tip-jet propelled rotorcraft to enter production. As such, the propulsion system involved a Turbomeca Palouste gas turbine engine that drove a pump to produce compressed air, which was in turn fed into the aircraft's hollow rotor blades to exit at their tips, causing the blades to rotate. The rotor hub assembly, which freely oscillated around a spherical thrust bearing, was mounted on a steel pylon by means of a ball joint and rubber shock absorbers. Unlike some of the experimental tip-jet designs of the era, a 'cold' tip-jet approach was used: that there was no combustion activity present at the exhaust nozzles installed at the ends of the rotor blades. Consequently, the nozzles produced little noise in operation, and were claimed by Sud-Ouest to be "noiseless".
The all-metal rotor blades, through which the compressed air travelled to be ejected at the blade tips, consist of a spar of tapering thickness, a honeycomb-filled trailing edge, and feature faired roots to increase their lift coefficient. It was claimed that the blades possessed a highly homogenous structure, a highly finished surface and a constant profile, and could be easily dismantled to facilitate inspection of the main spar. The blade had no risk of icing owing to the internal current of warm air. The Djinn used relatively standard flight controls, such as the collective pitch control (upon which the throttle was positioned) and adjustable friction trims."
Making its first flight on 2 January 1953, 178 examples of the Djinn were built, with the type seeing military service with the Armee de l'Air and the Bundeswehr.
Musee de l'Air 122
Next, more rotorcraft...