HAFNER GYROPLANE-Solving the Cyclic Control and Jump Take-Off.
Raoul Hafner was born in 1905 in Austria. He received his education at the University of Vienna and followed this with additional training at a technical college where he became fascinated with the ideas then circulating in the concept of rotary-wing flight. Following his education he was employed by the Austrian Air Traffic Company but he had this great desire to persue the development of a practical rotary wing aircraft and its potential of safer flight over fixed wing aircraft of the period. It should be recalled that many early aircraft did not have the stability of the aircraft of today. Stalls were a common cause of early accidents and Raoul, like Juan de la Cierva in England, believed the rotating wing concept to be the most practical means to overcoming this problem to aircraft safety.
In his spare time, Raoul began designing his first aircraft the R1. The “R” in the designation standing for “Revoplane”. This design suffered many problems of control and stability that many other early attempts at rotary-winged flight also encountered but Hafner was not that easily put down by the lack of success and started working on another design the “R2”.
In 1929 Hafner, with the financial backing of a cotton millionaire by the name of Major Jack Coates, left his job with the Austrian Air Traffic Company to solely concentrate on building the “R2”. The R2 “Revoplane” was a winged aircraft of single engine and single seat design. The aircraft had a single rotor that utilized a swashplate for controlling blade pitch and was one of the earliest forms of aircraft to employ this means of control. Outside of some somewhat brief tethered flight, the design was not successful in achieving free flight. 1932, Hafner moves to England and orders that the R2 be delivered to England as a rotor test rig. In 1933 Coates had the R2 delivered to Heston and it was in England were Hafner was able to make contact with the Cierva Company.
Cierva was finding success with his trademark “Autogiro” and Raoul was able to learn to fly in Cierva C.19 and C.30 Autogiro’s. Hanfer emigrated to England where he continued to study rotorcraft development independent of Cierva but also realizing that the autogiro design was the step needed for further testing and development toward a powered rotor.
While in Austria Raoul had the design idea for a third aircraft, the AR III, or R3, but building of the design did not begin until his move to England. The AR designation stood for Auto Rotation. This design incorporated design features of both the R1 and R2. This autogiro was designed at Hanworth, built by Martin-Baker Aircraft LTD. of Denham. The aircraft would become a very important historical aircraft in the development of powered rotary-wing flight control. The R III was an autogyro design which had a sensitive pitch control by use of the rotating swashplate and also included a mechanical means for collective control. In comparison, Cierva was controlling the rotor by simply placing the rotor on a gimbal with a stick control. Hafners design was to come to be called the spider cyclic-pitch control system.
In 1934, Hafner began full fledged construction of the R3 design with his new company the AR III Construction ( Hafner Gyroplane) Company. The R III used a hinged rotor design and with this incredible amount of rotor control was able to perform some of the most impressive “jump takeoff” demonstrations up to this period of technology. The craft was not able to hover as it was truly a gyroplane design. The RIII was able to achieve speeds up to 120mph, with a length of 17 feet and a rotor diameter of 32 feet 10 inches and a gross weight of 900 pounds.
The aircraft first flew in September of 1935 and made many demonstration flights from 1937 through 1940 registered as G-ADMV. The last flight being conducted in mid 1941.
Partly owing to the success of the design was the reliability of the 80 hp engine powering the aircraft. The powerplant used for the Hafner RIII was the Pobjoy Cataract engine. Douglas Rudolf Pobjoy began his engine work with Roy Fedden at Cosmos Engineering following World War I. Unfortunately Cosmos engineering fell into problems following the war and filed for bankruptcy. The remaining assets of the company were bouhgt out by the Bristol Aeroplane Company. Freeden stayed with Bristol which would later produce some very fine engines of their own.
In regards to the A.R. III, following a landing incident at Farnborough, the aircraft was fitted with a 95 hp Pobjoy Niagara III engine and christened the MKII model. The MKII first flew in February of 1937.
Douglas on the other hand entered service with the RAF as an education officer and met Nicholas Comper, designer of the Comper Swift. Comper needed an engine for his Swift and sought the work of Pobjoy. Pobjoy partnered with Parnell to develop the engine for Comper’s Swift. Rather than choosing to build a cheaper cast block in-line engine. They decided to produce a more expensive radial engine this radial arrangemenrt would provide for better cooling and a lighter weight for the same hp engine produced. The Swift would fly from London to Australia in nine days and two hours.
The success of the Swift saw additional requests for the engine and Pobjoy started producing various engine sizes many of which also found use in gyroplanes or autogyros of the time. Initial production began in Wirral (1928-1934). In 1934 the company moved to Rochester, Kent to be closer to their largest customer of their engines, Shorts. The bad economy from the Great Depression and the costs of moving the Pobjoy plant spelled financial ruin for the company and was bought out by Shorts.
Douglas Pobjoy would continue to work in aviation designing deicing equipment for high altitude aircraft. On the fourth of July, 1948 Pobjoy was on a return flight from Helsinki when the DC-6 he was aboard collided with an Avro York in cloud cover, killing the 39 passengers within the two planes. Douglas Pobjoy and his remarkable little engines powered many successful aircraft including the Hafner RIII.
Raul Hafner married, in 1936, to Eileen Myra McAdam, and they had one daughter, Ingrid Hafner born in the same year. Eileen McAdam was a descendant of John Loudon McAdam who invented the process of macadam, or tarmac road construction. Ingrid would grow up to become a rather well known actress.
Eileen Hafner is best remembered for her role as Carol Wilson in the first season of the television series The Avengers. She had also played Amanda Gibbs opposite Ian Hendry in the series Police Surgeon. Ingrid studied at the Bristol Old Vic Theatre School and followed her schooling by joining the Old Vic under Michael Benthall, where she played ‘Sylvia’ in “The Two Gentlemen of Verona”; ‘Lavina’ in “Titus Andronicus”, ‘Iris’ in “ Anthony and Cleopatra” and ‘Lady Anne’ in “Richard III”.
Other theatre includes repertory at Windsor, Colchester, Glasgow Citizens, Richmond Theatre (15 plays), “From the French” at the Strand Theatre in the West End, “Jungle in the cities” at Stratford East and numerous productions as Bristol Old Vic, including her first appearance there in “Cyrano” in which she played ‘Roxanne’:
The Hafner clan certainly seemed to have the blessing of becoming famous but for our concern over Raul Hafner he would continue to support the advance of the autogyro and development of the helicopter. Within England an ensuing controversy between proponents of the autogyro and of the helicopter would develop. Hafner made his views clear in a Royal Aeronautical Society lecture on October 14, 1937, when he advocated the rotating wing concept.
From 1938 he was with Pobjoy-Short at Rochester, but in 1940 was interned as an enemy alien, being released when his naturalization came through. He then developed the Rotachute, a rotary parachute to be towed behind an aircraft, for landing agents in enemy territory; this was made and tested at the Airborne Forces’ Experimental Establishment development section at Sherburn-in-Elmet. The little aircraft would inspire future gyroplane builders such as Ken Wallace. The Rotochute was followed by the Rotabuggy, a rotor-equipped Willys MB, but nether project entered known active service. The Rotochute would become the inspiration that would later fuel the homebuilder market for personal gyroplanes.
The Rotochute was developed, initially, as a personal recovery device to be used in place of a parachute. The project began in 1940 due to shortages of silk for parachutes and in the quest for an acceptable alternative Hafner proposed the Rotochute. The design was a two bladed backpack device that when deployed the blades would unfold and descend the occupant safely to the earth. Directional control of the device was accomplished by the jumper changing his body position. The first design, with a three foot rotor diameter was a failure and completed on 16 October of 1940. In November another attempt was conducted and proved to be a success. Various test were then conducted with different launch methods and even a delivery system using a ten foot rotor designated as the M-10 which flew on March 14, 1941.
This testing revealed that the launch phase was critical and the idea to continue as a manpack device was scraped for the idea of using the design as a basis for a small, air-deployable, delivery system. The original designation being the H-8 for this aircraft. Again, while elements of each of these first two developmental phases showed success; the ability to deploy the aircraft from another suitable aircraft was proving to be a difficult obstacle. The next phase, and the design we are most familiar with today, is the design being used as a towed gyrokite that when near its intended destination would be released from its tow cable and the soldier being deployed into the area of operation undetected in his small and virtually silent delivery system. In the truest sense of the term the Rotochute was the first stealth rotorcraft ever designed and built. Several variants of this design were successfully flown over the years into 1943. Over 20 different aircraft built conducting over 50 flights model number ran from P1 and subsequent. P5, which is a MkIII Rotochute is on display at the Museum of Army Flying at Middle Wallop.
The idea to make air deployable ground vehicles was the inspiration for the Rotabuggy. The design did not go very far in the research phase as the D-Day landings had shown that vehicles could be delivered in an easier fashion employing gliders and air-dropping with parachutes.
Many Thanks to Malcolm Auld for providing the rotorchute / rotobuggy video.
In 1944, following the build-up for the “D Day” invasion there was little left for Harfner and his team to do at the Airborne Forces’ Experimental Establishment and transferred to the Bristol Company to begin helicopter design and manufacturing.
This became the end of Hafners’ days of experimenting and designing gyroplanes and turned his devotion to helicopter research and design. He became the Chief Designer and developed the Type 171 helicopter which went into service with the RAF as the Sycamore. In terms of the use of the helicopter Hafner was more interested in the use of the aircraft in civil use rather than in military applications which led to the Type 194 in 1950. This design never reached fruition as the Bristol and Westland Aircraft Company merged in 1960.
Hafner was appointed technical director, holding this position until his retirement in 1970, and thereafter continued in a consulting capacity. During his decade with Westland he further propounded his convertible rotor ideas, as a means of increasing the helicopters range and speed by tilting its rotors for forward flight.
Raul Hafner unfortunately lost his life in 1980 in a sailing accident.
Raul Hafners direct contributions toward gyroplane development cannot be undermined as his RIII design was truly a state of the art machine and had all of the practical elements in one aircraft that directly led to the successful development of a practical helicopter.
Indirectly, Hafners work with the Rotachute would inspire future designers in Europe and abroad to develop practical gyroplanes for the average person after autogiro development practically ended with the development of the helicopter. In many ways the small gyrokites developed by Hafner and the Germans had a much larger contribution to future gyroplane development than the Cierva or Pitcairn designs. Hafner’s Rotochute and the German gyrokite would lead to the founding of small gyroplanes for sport and pleasure use. From this home spun revival of the autogyro design the future of the gyroplane as an industry may lie. From these humble designs, companies such as Groen Brothers and Carter Technologies have sprung who continue to test and push the advancement and applicability of gyroplane use.
My deepest appreciation to Malcolm Auld for providing the rotorchute / rotobuggy video.
“British Research and Development Aircraft, Seventy Years At The Leading Edge” by Ray Sturtivant, Published by Haynes Publishing Group, Sparkford, Nr Yeovil, Somerset BA22 7JJ, England. 1990. ISBN: 0-85429-697-2. Library of Congress card number, 90-80218.
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