The Nord 1500 Griffon was an

experimental An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when ...

ramjet A ramjet, or athodyd (aero thermodynamic duct), is a form of airbreathing jet engine that uses the forward motion of the engine to produce thrust. Since it produces no thrust when stationary (no ram air) ramjet-powered vehicles require an ass ...

-powered

interceptor aircraft An interceptor aircraft, or simply interceptor, is a type of fighter aircraft designed specifically for the defensive interception role against an attacking enemy aircraft, particularly bombers and reconnaissance aircraft. Aircraft that are cap ...

designed and built by French state-owned aircraft manufacturer

Nord Aviation Nord-Aviation ( en, Northern Aviation) was a state-owned French aircraft manufacturer. The bulk of its facilities were based on the site of Bourges airport, in the département of Cher, in central France. On 1 October 1954, Nord Aviation was cr ...

. The Griffon was developed to become a Mach 2 follow on to the supersonic

Nord Gerfaut The Nord Gerfaut (Gyrfalcon) was a French delta-wing experimental research aircraft. It was the first European aircraft to exceed Mach 1 in level flight without the use of an afterburner. A pair of aircraft were built for the primary purpose o ...

research aircraft. Development of the aircraft began in earnest after the receipt of a letter of intent in 1953 for a pair of unarmed research aircraft. The design featured an innovative dual propulsion

turbojet The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...

configuration; the former being used to

takeoff Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff. For aircraft that take off horizontally, this usually involves starting with a t ...

and attain sufficient speed to start the latter. The first

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...

, named Griffon I, made its

maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. The maiden flight of a new aircraft type is alwa ...

in 1955 and eventually reached a speed of Mach 1.3. Because it lacked the ramjet engine, it was mostly used for exploring the aircraft's aerodynamic properties and its systems. Its flight testing was terminated shortly after the ramjet-equipped Griffon II made its first flight two years later. This aircraft attained a maximum speed of Mach 2.19 and set a world record for a small closed course in 1959. It was last flown in 1961 and currently resides in the '' Musée de l'air et de l'espace'' outside

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

, France.

Development and description

The Nord 1500 Griffon originated from a state-sponsored study into delta and swept wings. To provide data for these studies

Arsenal de l'Aéronautique Arsenal de l'Aéronautique (commonly named Arsenal) was a national military aircraft manufacturer established by the French Government in 1936 at Villacoublay. In the years before World War II, it developed a range of technically advanced fighter ...

(SFECMAS's nationalised predecessor) built a wooden glider, the

Arsenal 1301 The Arsenal 2301, Arsenal Ars.2301, SFECMAS 1301 or SFECMAS Ars.1301 was an experimental French air-launched glider, built to test the aerodynamics of aircraft of novel configuration at full scale. It first flew in 1951 with swept wings but after ...

, that could be fitted with both

delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...

and

swept wing A swept wing is a wing that angles either backward or occasionally forward from its root rather than in a straight sideways direction. Swept wings have been flown since the pioneer days of aviation. Wing sweep at high speeds was first investigate ...

s and with and without canards. Towed to the release point by

SNCAC Martinet The SNCAC Martinet was a German-designed but French-built twin-engined military trainer and light transport monoplane. It was operated by the French military and in small numbers by French airlines from the late 1940s. Development To aide the Ge ...

Douglas DC-3 The Douglas DC-3 is a propeller-driven airliner manufactured by Douglas Aircraft Company, which had a lasting effect on the airline industry in the 1930s to 1940s and World War II. It was developed as a larger, improved 14-bed sleeper version ...

SNCASE Languedoc The SNCASE SE.161 Languedoc was a French four-engined airliner produced by SNCASE (Sud-Est). Developed from the Bloch MB.160 and known in the late 1930s as the (SNCSO) Bloch MB.161, the SE.161 was in service with Air France and the French milita ...

transport aircraft, the glider provided valuable data for the design of the Gerfaut.Hartman 2007, p. 12 To utilise this data SFECMAS's chief designer, Jean Galtier, initiated the 1400, 1500 and 1910 interceptor projects with delta wings and different types of propulsion systems. The 1400 developed into the

series, the 1500 became the Griffon, while the 1910, ambitiously specified with two large

engines, was never pursued. Galtier envisioned the Griffon as the Mach 2 successor to the supersonic Gerfaut. By this time Arsenal had been privatised as SFECMAS - ''Société Française d'Etude et de Construction de Matériel Aéronautiques Spéciaux''. Powered by a large ramjet with turbojet sustainer, the Griffon was renamed from the SFECMAS 1500 Guépard (Cheetah) after SFECMAS was merged with

SNCAN SNCAN, (abbreviated from ''Société nationale des constructions aéronautiques du Nord''), or commonly, Nord, was a state-owned French aircraft manufacturer in the pre- and post- World War II era. The company had been formed as one of six state ...

to form

. On 24 August 1953, a pair of prototypes were ordered, although the final contract (No. 2003/55) would not be issued until 1955. Although intended by Nord to eventually fulfil a requirement for a light

interceptor Interceptor may refer to: Vehicles * Interceptor aircraft (or simply "interceptor"), a type of point defense fighter aircraft designed specifically to intercept and destroy enemy aircraft * Ford Crown Victoria Police Interceptor, a police car * ...

capable of using grass airfields, these two aircraft were ordered without any military equipment installed, being intended for research purposes only. Much like he did with the Gerfaut, Gaultier opted for a straight-through air duct to keep the air entering the engines as calm as possible and positioned the single-seat cockpit immediately above the semi-circular ventral air intake. The large tubular fuselage supported the same

delta wing A delta wing is a wing shaped in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta (Δ). Although long studied, it did not find significant applications until the Jet Age, when it proved suitabl ...

as used on the Gerfaut and the swept

vertical stabilizer A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...

with

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

. The forward fuselage had small triangular canards positioned at either side of this cockpit to counteract the center of pressure of the delta wing's tendency to depress the nose as the aircraft approached

transonic Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transonic ...

speeds. The aircraft was fitted with a

tricycle undercarriage Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', arranged in a tricycle fashion. The tricycle arrangement has a single nose wheel in the front, and two or more main wheels slightly aft of the center of gravity. Tricycle ge ...

that retracted into the wings and the underside of the air intake. A key innovation of the Griffon was its dual-propulsion arrangement, which incorporated a

powerplant. The turbojet would enable the aircraft to perform unassisted takeoffs (ramjets cannot produce thrust at zero airspeed, and thus cannot move an aircraft from a standstill) while the ramjet would providing additional thrust once the aircraft had attained an airspeed in excess of 1,000 km/h (600 mph). To reduce risks in using the turbo-ramjet powerplant, the first Griffon (Nord 1500-01 Griffon I) was built with only the

afterburning An afterburner (or reheat in British English) is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat ...

SNECMA Atar 101 The SNECMA ATAR 101 is a French axial-flow turbojet engine built by SNECMA. It was derived from engines and design work carried out at BMW in Germany during World War II, and extensively developed though a progression of more powerful models. T ...

G21 turbojet engine installed with the ramjet to be added at a later date.Buttler & Delezenne 2010, p. 186

Flight testing

The Griffon I made its

on 20 September 1955, piloted by

André Turcat Major André Édouard Turcat (23 October 1921 – 4 January 2016) was a French Air Force pilot and test pilot celebrated for flying the first prototype of Concorde for its maiden flight. Turcat was born on 23 October 1921 in Marseille (Bouches-du ...

. Flight testing quickly proved the aircraft to be underpowered, a determination that was compounded by the cancellation of plans to install the planned ramjet propulsion system. Despite this reported lack of power, the Griffon I still managed to attain a maximum speed of Mach 1.15 on its first supersonic flight on 11 January 1956. At some point during its life the air intake was enlarged, probably when the more powerful Atar 101E engine was installed and before the aircraft attained its maximum speed of Mach 1.3 at an altitude of . Although the initial flight testing showed that engine performance above suffered, the aircraft's handling qualities were excellent. Its nose gear collapsed on 19 June when Turcat was

taxiing Taxiing (rarely spelled taxying) is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircra ...

across a grass field and the aircraft did not fly again until 26 July. The Griffon I was largely similar to the later ramjet-equipped Griffon II; amongst the few visible differences between the two aircraft were the smaller intake and the two-position exhaust nozzle used only on the Griffon I. It was retired on 16 April 1957. The Griffon II was fitted with the combination of an Atar 101E-3 turbojet and Nord ramjet. To accommodate the diameter of the latter, the aft fuselage was lengthened and widened and its greater requirement for air meant that the ventral air intake had to be enlarged. The aircraft made its first flight on 23 January 1957 and its first supersonic flight occurred on 6 April. Performance was disappointing as it failed to exceed the Mach 1.3 of the Griffon I as the ramjet was still not receiving enough air to fully power it. The Griffon II subsequently had the intake enlarged yet again and reached Mach 1.85 on its first test flight afterwards. The Griffon II set a speed record of on 5 October 1959.Gaillard, p. 35 It attained a peak speed of Mach 2.19 at while being piloted by Turcat on 13 October. Turcat had earlier broken the world record for the closed-circuit course by over with a speed of on 25 February, an achievement for which he was honored with the

Harmon Trophy The Harmon Trophy is a set of three international trophies, to be awarded annually to the world's outstanding aviator, aviatrix, and aeronaut (balloon or dirigible). A fourth trophy, the "National Trophy," was awarded from 1926 through 1938 to t ...

. The

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...

(USAF) contributed some money for the flight testing until 1960. No flights were made at all between February and July of that year and the Griffon II made its last flight on 5 June 1961. The flight-test program had revealed several technical difficulties were present in the aircraft, including concerns regarding

kinetic Kinetic (Ancient Greek: κίνησις “kinesis”, movement or to move) may refer to: * Kinetic theory of gases, Kinetic theory, describing a gas as particles in random motion * Kinetic energy, the energy of an object that it possesses due to i ...

ally-generated heat. One particular area of concern was the ramjet exhaust temperature which frequently damaged the tailpipe, another was the skin temperature of the airframe's

Duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''. Its use as a tra ...

-alloy skin. Flight tests also focused on trying to control the ramjet, which could not be throttled up or down, just on or off, via adjusting the fuel/air ratio. Pilots reported that the Griffon II's flight characteristics were excellent at all speeds: the ramjet could be ignited across a very wide band of speeds and its air intake was insensitive to

angle of attack In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...

issues. Furthermore its ability to maintain acceleration in a turn was instrumental to its success in the closed-circuit record performance.

Variants

;SFECMAS 1500 Guépard :The original designation and name of the initial design studies carried out at SFECMAS. ;Nord 1500-01 Griffon I :The first aircraft completed with only the SNECMA Atar 101F afterburning turbojet component of the planned turbo-ramjet powerplant. ;Nord 1500-02 Griffon II :The second aircraft fitted with the definitive turbo-ramjet powerplant.Carbonel 2016, pp. 93–94

Operators

;

Aircraft on display

The Nord 1500 Griffon II is presently on display in the

French Air and Space Museum French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

, at

Le Bourget Le Bourget () is a Communes of France, commune in the northeastern suburbs of Paris, France. It is located from the Kilometre zero#France, center of Paris. The commune features Paris - Le Bourget Airport, Le Bourget Airport, which in turn hos ...

, near Paris.

Specifications (Nord 1500-2 Griffon II)

References

Citations

Bibliography

*Buttler, Tony and Jean-Louis Delezenne. ''X-Planes of Europe: Secret Research Aircraft from the Golden Age 1946-1974''. Manchester, UK: Hikoki Publications, 2010. *Carbonel, Jean-Christophe. ''French Secret Projects 1: Post War Fighters''. Manchester, UK: Crecy Publishing, 2016 * El-Sayed, Ahmed F. ''Fundamentals of Aircraft and Rocket Propulsion.'' Springer, 2016. . * * *

External links

Overview of the Griffon program
(in French)

(in French)

(in French)

(in French) {{Nord aircraft 1950s French experimental aircraft Ramjet-powered aircraft Low-wing aircraft Griffon Canard aircraft Aircraft first flown in 1955