Cierva Gyrodyne

My paper on the Cierva (later Fairey) Gyrodyne is also available for those interested. This appeared in a 2008 edition of Vertiflite.

Email me at [email]jph@wt.net[/email] for a copy.

I have researched the Air Horse extensively and have obtained a large number of documents on the aircraft from the UK National Archives (that place is a gold mine of aviation history).

A few facts:

There was persistent heavy vibration in the front rotor that was only partially ameliorated.

Top speed never exceeded about 70 mph because of vibration.

Control was a problem since opposite rigging was required for powered flight vs. autorotative flight. The demonstration flights at the 1949 Farnborough Air Show included mainly right turns because of poor control authority when making left turns. Vibration when flying to and from Farnborough was also a serious concern.

The Air Ministry imposed a fixed-price development contract on the project which left the Cierva Autogiro Company chronically short of funds with too much effort spent in requesting further finances. On the bright side, the AIr Ministry praised the Cierva Autogiro Company for efficient management of resources during the course of the contract.

The crash was caused by fai;ure of the swashplate driving link in the front rotor – poor machining was involved as in the Fairey Gyrodyne accident – which caused the collective pitch to increase to maximum value and resulting in the reported pitch up followed by the dive into the ground.

I have studied the history and development of gyroplanes quite extensively, own and operate two Air & Space 18A gyroplanes, and hold CPL/CFI in gyroplanes (among other qualifications) and offer the following observations for your considered opinions.

1. A gyroplane must be designed, constructed, and maintained to accepted aeronautical standards to be considered safe and reliable for everyday use. The Autogiros of the Cierva company (and its licensees), though each successive model incorporated sometimes significant improvements or differences from those preceding, were produced and operated by aviation professionals. This resulted in the outstanding safety record for this type of aircraft in terms of fatalities and injuries, even though accidents occurred with some regularity. Experimental gyroplanes, with very few exceptions, are designed, built, and operated by amateurs which has resulted in the very bad reputation now attached to this type of aircraft.

2. When the gyroplane was superceded by the helicopter, development of the former ceased and further rotorcraft advances passed it by. The helicopter has benefited enormously from concentrated development over the past 65 years; conversely, the gyroplane was developed during the period of 1920 – 1940 (or so) by probably less than 50 qualified engineers worldwide.

3. The gyroplane can easily land in an area from which it cannot take off, unless substantial jump-takeoff performance is available. A jump-takeoff is a low performance maneuver since most the energy is expended is the first five seconds and used to sustain the aircraft in the air while it is accelerated to a climb airspeed which may or may not provide adequate performance to clear obstacles. The minimum permissible gyroplane rotor r.p.m. for takeoff should provide jump takeoff capability.

4. Gyroplanes need a tail rotor. Any aircraft that can routinely operate at airspeeds where control about one or more of its axes is degraded must be fitted with a control system to eliminate that deficiency.

5. Gyroplanes should avoid operating from runways, particularly at busy airports, when possible, to avoid traffic conflicts due to the time required for takeoff, and the airspeed differential between it and faster airplanes during climb.

6. Gyroplanes can easily operate from a non-runway area on an airport when such operations can be conducted without hazard.

7. Gyroplanes should not takeoff when insufficient clear area is available under the flight path in the event of emergency.

8. The maximum climb angle attainable by a gyroplane after liftoff is at best equivalent to that of STOL airplanes.

9. Gyroplanes can maneuver as necessary after takeoff to avoid obstructions, depending on performance available.

10. Gyroplanes should not execute a landing approach to an area where conflicting traffic can appear at the last moment since go-around performance in the landing flare is at best marginal.

11. Gyroplanes can especially benefit from a combination of a modern hingeless rotor and vibration control technology.

12. Gyroplanes can be safely maneuvered without regard to minimum airspeed or rotor r.p.m. as necessary to meet a potentially hazardous situation.

13. Gyroplanes can fly safely at altitudes and airspeeds which are unsafe in other types of aircraft, particularly at low altitude.

14. The inherent safety of the autorotating rotor significantly reduces pilot stress and workload in both normal and emergency operations.

15. Irreversible controls, three axis trim and a rotor stability augmentation system significantly reduce pilot fatigue on a long flight in a gyroplane.

16. Gyroplanes can easily execute a precautionary landing, off-airport if necessary, without hazard to persons or property.

17. Gyroplanes must have provide payloads comparable to airplanes of similar size to be useful.

18. Gyroplane performance must enable the completion of flights of reasonable range within periods comparable to those commonly undertaken with comparable aircraft, e.g. two to three hours or so.

19. Controllability and performance necessary to successfully and reliably execute landings in crosswinds up to at least 10 knots must be provided. Crosswind landings in an Air & Space 18A, for example, are not recommended, even though approved in the flight manual, due to the ease with which loss of control can occur at the very last stages of the maneuver.

20. Pilot training for gyroplanes is available but sometimes hard to find.

Included herein are observations published in my article available at http://www.gyroplane.aero/gyroplane_xc_article.html