Autogiro Principle Adapted to Helicopter (Oct, 1931)

Autogiro Principle Adapted to Helicopter

HARRY T. NELSON, a war-time aviator now living in Dallas, Texas, has recently developed a helicopter which has proved very successful in the model stage and which he believes to be a solution of the problem of vertical flight.

One outstanding feature of the machine is the means of rotating the large horizontal propeller at the top. This is done by the slipstream of the powered propellers situated directly below it and turning in opposite directions. This big propeller, which rotates freely; in much the same manner as the rotor blades of an autogiro, not only assists in lift

and getting a “toe-hold” on the air, but acts as a vertical stabilizer and as a parachute in landing.

The lower propeller takes hold similar to the clutch on a bicycle, and coasts when the motors are dead. The speed of the large propeller may be built up gradually just before taking off vertically, thereby giving elasticity to the contact between the motors and the large propeller. As soon as the speed is built up a vertical drop is impossible.

As soon as the desired altitude is reached, horizontal travel is attained by tilting the machine slightly in the desired direction.

  1. Stephen says: October 13, 20116:31 am

    All those vanes and struts add up to a huge amount of extra drag and weight.

  2. Hirudinea says: October 13, 20119:46 pm

    So he drives a propeller with propellers? Seems kind of wasteful to me.

  3. Pardik says: October 14, 20113:43 am

    Hirudinea, the modern helicopter’s turboshaft engine actually does just that:…

  4. Pardik says: October 14, 20113:52 am

    Or rather not, it drives a propeller with the expanding hot gas. but the “elastic clutch” priciple is similar…

  5. Dan says: December 5, 20117:11 am

    From what I understand is that it allows for a safe landing even if there is no power! Nice in an age when motors weren’t as reliable as they are today.

  6. Toronto says: December 5, 20118:43 am

    Dan: A helicopter can autorotate to a safe landing with no power, given sufficient altitude, space, and skill.

  7. observer says: January 26, 20122:56 am

    Toronto: an engine failure in a helicopter at anything less than 200 feet is always invariably fatial, regardless of how well trained or skillful the pilot might be

  8. Charlie says: January 27, 20127:52 am

    observer: Wouldn’t that imply that an engine failure at 6″ would be fatal?

  9. Nomen Nescio says: January 27, 20128:02 am

    a better way to put it is that engine failures in a helicopter below about that altitude are unrecoverable, meaning the pilot can do nothing and Newtonian mechanics alone determine the outcome. autorotation is a critical emergency procedure for helicopter pilots to learn and practice, but it does indeed require enough altitude that a fall from considerably less might still kill you.

    i suppose there might be some way to die from a six-inch fall, even if you’re seated in a padded helicopter chair. i can’t think of one at the moment, but my imagination isn’t perfect either.

    (true autogiros can and do autorotate at any altitude. it’s how they stay in the air, and how they land. pity they’re as slow as helicopters while still requiring the runway of a small fixed-wing plane to take off, among other shortcomings.)

  10. Charlie says: January 27, 201212:34 pm

    Nomen: I guess the easiest way to die from a 6″ fall would be if your helicopter was upside down.

  11. observer says: January 30, 20122:31 am

    Charlie: If your helicopter was upside down at a hieght of 6′, it would mean your helicopter has flipped possibly as a result of ground resounance. Add to that if the blades are spinning when it hits the ground then I wouldn’t want to be the unfortunate pilot or anyone close by, ESPECIALLY WITH BROKEN BITS OF BLADE FLYING ALL ABOUT OR FIRE FROM SPILT FUEL Indeed even if a strapped in pilot were to experience a belly in landing from a hieght of 6′ there is a very good chance he/she could die – not so much from body injuries but from damage caused to the brain by sudden and violent impact of the aircraft with the ground. In fact many pilots die each year from seemly minor aircraft crashes that in therery they should have walked away from, because of this very reason!!

    Nomen: True Auto giros are in fact faster than an equivilant helicopter. [Witness the Farey Gyrodyne which broke a number of speed records, the Fairey Rotodyne, the Carter Copter to name but three] Their speed only being limited by how powerful the propelling engine is. However because most modern Autogiros or girocopters are classed as microlight aircraft by most governments and therefore restricted to how powereful an engine they can have, their maximun speed as a result is quite slow compared to a helicopter. It is also wrong to say Autogiros still need a short runway to take off, Autogiros can be and have been fitted with jump start mechanism which completely do away with any need for a run way. Autogiros can also hover like a helicopter if facing in to a sufficently strong wind ie the wind strength balances [or cancels out] the force of forward thrust produced by the engine and prop and because the autogiro is facing in to the wind, the wind continues to turn the blades generating lift, even though the autogiro is stationary.

    And one other thing Autogiros are safer than a helicopter. The number of autogiro accidents that do occur can in the main be attributed to inexperienced pilots or insufficent engine power for the pilot to get out of a difficult situation

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