Tipjets
Encyclopedia
Nozzle
A nozzle is a device designed to control the direction or characteristics of a fluid flow as it exits an enclosed chamber or pipe via an orifice....
s located at the tip of some helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
rotor blades. The objective is to spin the rotor, much like a Catherine wheel firework
Catherine wheel (firework)
The Catherine wheel is a type of firework consisting of a powder-filled spiral tube, or an angled rocket mounted with a pin through its centre...
.
Some tipjets rely solely on compressed air, provided by a separate engine
Engine
An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...
, to create jet thrust
Thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....
. Others use an afterburner
AfterBurner
The AfterBurner is a lighting solution for the Game Boy Advance system that was created by Triton-Labs.Originally, portablemonopoly.net was a website created to petition Nintendo to put some kind of light in their Game Boy Advance system...
type system to burn fuel in the compressed air at the tip (tip-burners) to enhance the thrust. Some are ramjet
Ramjet
A ramjet, sometimes referred to as a stovepipe jet, or an athodyd, is a form of airbreathing jet engine using the engine's forward motion to compress incoming air, without a rotary compressor. Ramjets cannot produce thrust at zero airspeed and thus cannot move an aircraft from a standstill...
s or even a complete turbojet engine. Some are rocket tip jets that run off stored propellant such as hydrogen peroxide.
Tipjets replace the normal shaft drive and have the advantage of placing no torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
on the airframe, so no tail rotor is required.
During the Second World War a German, Friedrich von Doblhoff, suggested powering a helicopter with ram jets. The first jettip powered helicopter was the WNF 342 V1
Doblhoff WNF 342
|-See also:-References:...
in 1943. After the war two WNF 342 prototypes ended up with the Americans and Doblhoff joined McDonnell Douglas
McDonnell Douglas
McDonnell Douglas was a major American aerospace manufacturer and defense contractor, producing a number of famous commercial and military aircraft. It formed from a merger of McDonnell Aircraft and Douglas Aircraft in 1967. McDonnell Douglas was based at Lambert-St. Louis International Airport...
who subsequently produced the McDonnell XV-1
McDonnell XV-1
|-See also:-Bibliography:* Connor, R. and R. E. Lee. . 24 September 2001. Smithsonian National Air and Space Museum, Washington, DC. Accessed 4 December 2007....
. The engineer who had actually produced the tip jet engines, August Stephan, joined the Fairey Aviation
Fairey
-People:*Charles Richard Fairey, British aircraft manufacturer*Francis Fairey, , Canadian politician,*Jim Fairey, outfielder*Shepard Fairey, American artist-Companies:*Fairey Aviation Company, British aircraft company...
company of the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
which used them in their Fairey Jet Gyrodyne
Fairey Jet Gyrodyne
|-See also:-Bibliography:* Charnov, Dr. Bruce H. The Fairey Rotodyne: An Idea Whose Time Has Come – Again? Retrieved: 18 May 2007.* Green, William and Pollinger, Gerald...
and Fairey Rotodyne
Fairey Rotodyne
The Fairey Rotodyne was a 1950s British compound gyroplane designed and built by Fairey Aviation and intended for commercial and military applications...
aircraft first flying in 1954 and 1957 respectively.
Eugene Michael Gluhareff
Eugene Michael Gluhareff
Eugene Michael Gluhareff was born in Saint Petersburg, Russia and moved to the United states in the early 1920s. Gluhareff was an engineer, the son of Michael Gluhareff of Sikorsky Aircraft. He is much acclaimed for his pioneering work on tip jets and was a contributor to the American Helicopter...
was an early pioneer of tipjets.
In engine-out scenarios the presence of tipjets on the rotor increases the moment of inertia, hence permitting it to store energy, which makes doing a successful autorotation
Autorotation (helicopter)
Autorotation is the state of flight where the main rotor system of a helicopter is being turned by the action of air moving up through the rotor rather than engine power driving the rotor...
landing somewhat easier. However, the tipjet also very typically generates significant extra air drag, which demands a higher sink rate and means that a very sudden transition to the landing flare must occur for survival, with little room for error.
Rotorcraft using tip jets
- Percival P.74Percival P.74|-See also:-References:NotesBibliography* Flight via flightglobal archive, 1955.* Winchester, Jim. The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books Ltd., 2005. ISBN 1-904687-34-2....
- underpowered, it never took off - Hiller YH-32 HornetYH-32 Hornet|-See also:-References:* Display information at Museum of Flight in Seattle, Washington* "The First 100 Years of Aviation"-External links:* * *...
had good lifting capability but was otherwise poor - Mil V-7Mil V-7The Mil V-7 was an unusual experimental four-seat helicopter with AI-7 ramjets at the tips of the two rotor blades. It had an egg-shaped fuselage, skid undercarriage, and a two-bladed tail rotor on a short tubular tail boom. Only one prototype was built in the late 1950s....
- soviet turbojet helicopter - Fairey Jet GyrodyneFairey Jet Gyrodyne|-See also:-Bibliography:* Charnov, Dr. Bruce H. The Fairey Rotodyne: An Idea Whose Time Has Come – Again? Retrieved: 18 May 2007.* Green, William and Pollinger, Gerald...
- provided data for the Rotodyne - Fairey RotodyneFairey RotodyneThe Fairey Rotodyne was a 1950s British compound gyroplane designed and built by Fairey Aviation and intended for commercial and military applications...
- 48 seater short-haul airliner design - Fairey Ultra-light HelicopterFairey Ultra-light Helicopter|-See also:-Bibliography:...
- four built for military use but no further orders - Fiat 7002Fiat 7002|-See also:-References:* Flight 1958* The Illustrated Encyclopedia of Aircraft , 1985, Orbis Publishing...
- Focke-Wulf Fw TriebflügelFocke-Wulf Fw Triebflugel-External links:* * * *...
World War II interceptor design — not built - McDonnell XV-1McDonnell XV-1|-See also:-Bibliography:* Connor, R. and R. E. Lee. . 24 September 2001. Smithsonian National Air and Space Museum, Washington, DC. Accessed 4 December 2007....
- Hughes XH-17 - flying crane (largest rotor of any type on a helicopter)
- Nederlandse Helikopter Industrie NHI H-3 Kolibrie (ca 11 built)
- SwissCopter of Innosuisse Corp. (DragonFly)
- Rotary Rocket Roton ATVRotary RocketRotary Rocket, Inc, was a rocketry company headquartered in a facility at Mojave Airport that developed the Roton concept in the late 1990s as a fully reusable single-stage-to-orbit manned spacecraft. Roton was intended to reduce costs of launching payloads into low earth orbit by a factor of...
- Sud-Ouest DjinnSud-Ouest Djinn|-See also:-References:* The Illustrated Encyclopedia of Aircraft , 1985, Orbis Publishing, Page 2975- External links :* rare photo of the single seat SO.1220 that tested the power concept -- ie bottom of page 128**...
- compressed air tip jets - JK-1 Trzmiel (polish prototype one-seat helicopter)
None apart from the Sud-Ouest Djinn have made it into production.