Glossary of gyroplane terms

How it flies

Autorotation

The rotor spinning under the force of air flowing up through the disc, rather than being driven by the engine. It is the principle a gyroplane flies on continuously, and the state a helicopter enters after an engine failure.

Gyroplane also Gyrocopter, autogyro, gyro

A rotorcraft whose rotor is turned by airflow rather than by the engine, with a separate propeller providing thrust. Regulators generally use "gyroplane"; autogyro and gyrocopter mean the same aircraft. Rotorcraft is the wider category and includes helicopters, so it is not a synonym.

Autogyro also Autogiro, gyro

Another name for a gyroplane. The same aircraft, not a different one. "Autogiro" with an i was Juan de la Cierva's trade name for his machines; the spelling with a y became the ordinary word and is still common in older books and outside the United States.

Gyrocopter also Gyro

Another name for a gyroplane, and the one most people search for. It came into use as a trade name and spread to mean the type generally. Regulators write "gyroplane"; almost everyone else says gyrocopter, and they mean the same machine.

Rotorcraft

The category of aircraft that get their lift from rotating blades rather than fixed wings. It covers helicopters and gyroplanes both, so it is a wider word than either: every gyroplane is a rotorcraft, and so is every helicopter, but a rotorcraft is not necessarily a gyroplane.

Rotor disc

The circle swept by the turning rotor blades. Much of how a gyroplane handles comes down to how the disc is tilted and how much air is flowing through it.

Prerotation

Spinning the rotor up mechanically before takeoff, so the blades are already turning when the ground roll begins. It shortens the roll; it is not what keeps the rotor turning in flight.

Rotor RPM also Rrpm

How fast the rotor is turning. Managing it is central to flying a gyroplane, and the acceptable range is specific to the type. The figures that matter are in the aircraft flight manual for your aircraft, not in a general reference.

Blowback

The rotor disc tilting back as airspeed increases, a natural consequence of the airflow through it.

Power push over also PPO, bunt over

A loss-of-control event associated with unloading the rotor while thrust is applied, more likely on certain airframe geometries. It appears repeatedly in accident reports, which is why type-specific instruction matters. Treat any general description, including this one, as background rather than as training.

The machine

Rotor head

The assembly at the top of the mast that carries the rotor blades and allows the disc to tilt. One of the components a pre-purchase inspection should look at closely.

Mast

The vertical structure carrying the rotor head above the airframe.

Pusher configuration

Engine and propeller mounted behind the cabin, pushing rather than pulling. The common arrangement on modern gyroplanes.

Enclosed and open cockpit

Whether the cabin has a full enclosure or the occupants sit in the open air behind a windscreen. Affects comfort, useful season and, usually, price.

Tandem and side-by-side

Whether the two seats are one behind the other or next to each other. Affects instruction, loading and cabin width.

Empty mass also Empty weight

The mass of the aircraft without fuel, occupants or baggage. Subtracting it from the maximum take-off mass gives what you can actually carry.

Maximum take-off mass also MTOM, MTOW

The heaviest the aircraft may be at the start of the takeoff roll. A limit set for the type and, in some countries, capped further by the category the aircraft is registered in.

Buying and owning

Airframe hours

Total hours flown by the airframe since it was built. Read it alongside engine hours: the two are often very different, and both should match the logbooks.

Time since overhaul also TSO, TBO when referring to the interval

Hours flown since a component, usually the engine, was last overhauled. The interval before the next overhaul is set by the manufacturer and is a real future cost to price in.

Airworthiness directive also AD

A mandatory instruction from a civil aviation authority requiring an inspection or modification on a type. Ask which ones apply and whether they have been carried out. Compliance is not optional and it can ground an aircraft.

Service bulletin also SB

A manufacturer notice recommending or requiring work. Whether it is mandatory depends on the authority and the category the aircraft sits in.

Logbook

The maintenance record for the airframe and engine. A gap in it is a negotiating point at best and a reason to walk away at worst. Verify advertised hours against it before agreeing a price.

Kit build

An aircraft assembled from a manufacturer kit rather than delivered complete. Build quality varies with the builder, which is why who assembled it is worth asking about.

Price on request also POR

A listing with no published price. On this site a price-on-request listing carries no price field at all rather than a hidden or placeholder figure.

Lien

A registered financial claim against the aircraft. In several jurisdictions it follows the airframe rather than the seller, so it can become the buyer's problem. Search for one before money moves.

Flying it

Type rating and conversion

Training specific to an aircraft type, taken in addition to the licence itself. What is required, and whether existing fixed-wing or helicopter hours count toward it, is set by your national authority.

Currency

Having flown recently enough to meet the requirements that let you carry passengers or act as pilot in command. The thresholds are national and they change; check yours.

Approval reference

The identifier a flight school publishes to show it is approved to instruct. This site reproduces what a school publishes and does not verify that it is current. Confirm it with the authority that issued it.

What is deliberately not here

Typical figures. There is no entry giving a usual rotor diameter, cruise speed or empty mass, because those vary by type and an average invented for a glossary is exactly the kind of number this site refuses to publish. Type figures live on the manufacturer pages, sourced individually.

Licence requirements. They differ by country and they change. The training directory lists schools by country; your national civil aviation authority is the only source that counts.

Once you have read a few of these, the knowledge quiz draws questions from them at random. Every answer links back to the term it came from.