HISTORY OF MODEL FLYING
The Chinese were flying kites by 1000 B.C. and may have tried to make them fly stringless, but in Europe it all started, as did so many things, with Leonardo da Vinci in around 1500. After trying to imitate bird flight with flapping wings, and failing to realise that man’s muscle power was not enough to produce lift by flapping, he designed a device with a fixed wing with flapping tips, and thus separated the functions of lift and thrust. He also had the idea of a helical screw helicopter, probably powered either by clockwork or by a twisted steel wire. He died in 1519 and his notes were not discovered till the nineteenth century. Without this 300 year lapse, gliders at least might have been flying by 1600, though the lack of suitably light yet strong materials held back development; cord, cane, paper, leather and feathers was all that was available.
It was Sir George Cayley who really made the breakthrough. He realised that instead of letting the wind push against a kite, it ought to be possible to make the kite push against the air. He replaced the kite string with a weight and added a stabilising tail. This tail included a fin and could be adjusted to alter the tailplane incidence and fin setting; the nose weight could be slid to alter the centre of gravity. You can see a replica in the Science Museum.
Cayley used a whirling arm test rig to develop airfoils and realised that a cambered airfoil produced more lift than the flat surface of his kite glider; he also found that dihedral improved lateral stability.
Frenchman Alphonse Penaud in 1871 did more than most to popularise air-mindedness and model flying. He demonstrated an inherently stable rubber-powered model, spanning only 18 inches and with a feather-bladed pusher propeller. His Planophore flew for 11 seconds and covered 131 feet during a demonstration in the gardens of the Tuileries in Paris. His name lives on today with the Penaud Trophy, awarded to the top-placing national team flying rubber-powered F1B Wakefield models at the World Free-Flight Championships.
Probably qualifying as the noisiest model aircraft ever, Gustave Trouve produced a wing-flapper or ornithopter that was powered by twelve blank revolver cartridges that fired into a curved, springy Bourdon tube, as used in barometers. As the tube straightened it pulled the wings down and as it returned to its normal shape they sprang back to the upper position. Although this device flew for a couple of hundred feet Trouve then sensibly concentrated on propeller research.
In Australia Lawrence Hargrave built successful rubber-powered ornithopters, using a stiff leading edge but a power-driven flexible rear part. He and his models recently appeared on the $20 bill.
Various experiments with helicopters continued, but it was the lack of an engine that had a high enough power/weight ratio that held back both rotary winged and fixed wing development.
After the Wright brothers made the first manned powered flight in 1903 things accelerated, with many of those involved in aviation starting their careers as model flyers. Among them were Fairey, Sopwith, Handley-Page, de Havilland, Hurricane designer Sidney Camm and A. V. Roe. All were members of the Kite and Model Aeroplane Association, which later became the Society of Model Aeronautical Engineers, now the BMFA, and the world’s oldest model flying organisation. Later model flyers included Sir Frank Whittle, Neil Armstrong and Paul Macready, whose Gossamer Condor was the first successful man-powered aircraft. It was Macready who designed the first slipstream deflectors now used on top of the cabs of many articulated trucks to reduce drag and improve fuel consumption.
A. V. Roe flew a nine foot span rubber-powered model in a competition at Alexandra Palace in 1907, beating 129 other flyers with a flight of 30 yards, and using his winnings of £50 to build his first man-carrying triplane. He went on to found the Avro company which produced the Lancaster.
The following year T.W.K. Clarke set up business in Kingston, near the site where the Sopwith factory would soon be producing Pups and Camels. The Clarke Patent Flyers were rubber-powered and came in four sizes from one foot to three feet long. The largest had wings carved from cedar wood and were capable of 400 foot flights. One is on display in the Science Museum.
In 1909 the K&MAA ran a popular series of weight-lifting contests for rubber-powered models that had to weigh at least a pound, and the trophy for this is now the BMFA’s oldest contest award, today being for free-flight gliders to the World Championships specification.
Regular contests were flown in Windsor Great Park, Warwick racecourse and on Wimbledon Common, and photos exist of competitors dressed in plus fours, straw hats and stiff collars, clutching a variety of rubber-powered aircraft. A-frame pushers were common, with a canard layout and twin propellers at the rear.
Later, in 1914 just before the outbreak of war, David Stanger built a V-twin petrol engine that turned a 22 inch propeller, put it in a seven foot span canard biplane which he took to Hendon airfield and set a British record of 51 seconds, duly timed by Royal Aero Club observers.
Another motive power was compressed air. Thin copper cylinders, wire-bound to withstand the pressure, were hand-pumped to 200 p.s.i., and drove multi-cylinder motors; like full-size aircraft of the time their wings were wire braced to resist flexing in flight and many had a projecting skid to protect the vulnerable propeller on landing. Most models were covered with oiled silk, and the structure was of steel wire and spruce or birch.
Across the Atlantic, Armour Selley had been experimenting since 1910 with a new material from South America, balsa wood; over here, however, it wasn’t till a US flyer, Joe Earhart, won the coveted Wakefield Cup in 1931 with a balsa and tissue model that British model flyers caught onto the fact that balsa might have something to offer.
The same year that Lindbergh crossed the Atlantic solo, 1927, Lord Wakefield, who owned the Castrol oil; company and was a major patron of aviation, donated a cup to the SMAE, and model flying went international. The Wakefield contest was at first for aircraft with any form of power and there was a maximum weight limit of eleven pounds. The models had to take-off from the ground and flight duration was the sole aim. Soon the event was for rubber-powered aircraft only and the Wakefield Cup contest was held every year till the War interrupted things. The challenge of competition led to free-wheeling propellers to reduce drag after the rubber power was exhausted, and then propellers with folding blades; some models had return gears so twice the motor length could be held in the fuselage, thus doubling the power run. Flyers soon found that more turns could be wound onto a rubber motor by stretching it, sometimes to 6 or 7 times its normal length. Today’s Wakefields, or F1Bs, can be hand launched, are limited to just 30 grams of rubber, - about an ounce, - must weigh 230 grams or more and have a maximum surface area limit. Designing and flying an aircraft to get the maximum performance out of a limited amount of energy is still at the heart of free-flight today.
In the early 1920s American physicists doing research into optical diffraction needed a very thin transparent film, and found that a cellulose material called collodion, poured onto the surface of water, would spread out like an oil film a few microns thick to give them just what was required. Pretty soon model flyers in New York, who held winter indoor contests in school halls and armouries, heard about this material and modified it to become microfilm. Tissue-covered indoor models had been managing flights of around ten minutes, but at the 1932 US Nationals three microfilm-covered aircraft all flew for almost double the time. The 1930s were the time of airships, and hangars in the USA built to house the Akron and Macon were used for indoor competitions; in Britain the airship shed at Cardington is still used for indoor flying today and a salt mine in Romania is often the venue for World Championships.
In Britain the Kite and Model Aeroplane Association had merged with the London Aero Models Association and in 1922 the name was changed to the Society of Model Aeronautical Engineers, a name suggested by Sidney Camm, designer of the Hurricane and other Hawker aircraft. The SMAE, today known as the BMFA, is the world’s oldest model flying organization.
At the 1933 US Nationals Maxwell Bassett flew a model powered with a spark ignition engine and beat many of the other flyers using rubber power. The engine was an early version of the 10 c.c. Brown Junior, and soon after that separate classes were run for rubber power, compressed air or internal combustion engines. Meanwhile Bill Brown sold 50 thousand of his engines in six years to a nation that was becoming increasingly air-minded.
The world airsports organisation, the Fédération Aéronautique Internationale, introduced contest rules for model flying in 1936, and several annual international contests were held. Germany and the USSR quickly saw the potential for model flying as a means of encouraging air-mindedness in young people. Hitler Youth organized national competitions and almost every Young Pioneers centre in the USSR had model building workshops; in the East bloc countries this massive support for model flying resulted in numerous international wins and a lot of technical development. The Master of Sport title was awarded to top-ranking Soviet model flyers as well as to gymnasts and footballers.
In 1937 at the US Nats there was a contest for radio-controlled models. Of the six entries, three flew and one of them, Chester Lanzo’s, appeared to be under radio control, as it deviated slightly from its straight course when the flyer operated the transmitter key. The model had a nine foot wingspan and the on-board gear weighed two pounds. It used the 80 metre amateur radio band and occasionally would respond to signals from amateurs hundreds of miles away Competitors built their own equipment, all, of course, valve-based; most early models had only the rudder controllable and that either fully left, fully right or neutral. The following year another flyer arrived with a fourteen foot model weighing 28 pounds and using four separate receivers, one each for left and right rudder and up and down elevator. It failed to fly, but was awarded second place.
When the War started, Reginald Denny, a well-know film actor and model flyer, developed radio-controlled target drones for gunnery training, and it was a variant of this equipment that was used on the explosive-filled B-17s in the experimental Aphrodite project. A malfunction of the gear killed President Kennedy’s brother who was piloting it onto its course before intending to bail out and leave it to RC.
During the War the flying of petrol-engined models was banned in Britain because of the risk of confusion with hostile aircraft, but two-stroke model diesel engines, or more correctly compression ignition engines, were developed in Switzerland and after the War became popular in Europe. Early British engines like the Mills 1.3 and the 2 c.c. ED Competition Special made power flying accessible to people who could not afford the high cost of American spark ignition engines. Due to import restrictions and the shortage of dollars, one source of US engines was via jazz musicians playing on the transatlantic liners, who would smuggle Super Cyclones and Ohlsson 23s back to the UK, along with nylons and smart shirts.
Another wartime development in the USA was control-line flying; developed by Jim Walker, who had won the RC event at the 1941 US Nats with the first model with proportional rudder control. Walker’s famous Fireball got many people started in CL flying, or U-control, as it was known in the USA. A great showman, Walker flew three Fireballs at once at demonstrations, with a control handle mounted on a special helmet, and two speed ignition control, which enabled the models to be hovered vertically so that he could burst balloons with a pin on the tail of each model.
Britain lagged behind the USA in adopting CL flying but at the second British Nationals in 1948, the first contests for aerobatics and speed were held; later on team race and combat were added. The first team race contests had three man teams and allowed engines up to .29s, rather than the current 15s allowed for F2C. After some early rather dubious control-line speed records the anti-whip pylon was required from 1949.
The previous year saw 685 people competing in the six free-flight contests at the first Nationals at Gravesend airport. In that same year, 1947, the Fédération Aéronautique Internationale decided that model flying was now so large a sport that it needed its own commission and CIAM, the Commission Internationale d’Aeromodellisme was formed, with British delegate Alex Houlberg as its first president. In the late 1950s Houlberg received the OBE for services to model flying.
In Britain several large annual contests were held in the 1940s and ‘50s; the Northern Heights club ran their event at Hawker’s airfield at Langley, with newly-built Tempests and Sea Furies lined up near the hangars, St Albans ran the All-Britain Rally at Handley-Page’s airfield at Radlett, with TV and cinema newsreel coverage, and the Yorkshire Evening Post and Stockport Express also sponsored contests. Northern Heights had several high-level contacts, including its president, aeronautical research pioneer Dr. A. P. Thurston. As a result various VIPs ranging from the Queen to a First Sea Lord and test pilot Neville Duke were on hand to present the prizes.
Until the 1950s most airfoils used for models were similar or identical to those used on manned aircraft. However, in Hungary in 1944, as US Liberators were bombing Budapest, a young engineer called György Benedek was the other side of the Danube, testing some new airfoils specifically designed for duration models; till then wind tunnel tests had been at quite high Reynolds numbers but Benedek used the absolutely still air of a Central European dawn to do flight measurements that produced radically different sections that are still used for free-flight today. He also realized the importance of turbulators to improve lift on free-flight model wings.
Jetex solid fuel rocket motors appeared in 1948; contests for this class were held for several years in Britain.
1949 saw the first RC aerobatic contest at the British Nationals; out of 42 competitors only 9 managed to score any points. Early equipment used super-regenerative receivers and rubber-powered or sometimes clockwork escapements, allowing either left or right rudder or else neutral, obtained sequentially, so it was important to remember what rudder position the last signal had produced in order to decide how often to press the transmitter key for the next one. More advanced equipment gave throttle control via a quick blip on the key; superhet receivers gave better selectivity and allowed more than one model to be flown at once. Other control systems included the Ruddervator; behind the tailplane was an angled rotating vane which could be stopped in one of four positions to give up or down elevator effect and left or right rudder. Later developments involved tuned reeds; different tones could be transmitted and the receiver fed these to a bank of tuned reed relays, each responding to just one tone and operating one of the aircraft controls in one direction. This allowed full deflection of the chosen control surface. Rudder and ailerons were on the right hand whilst progressive throttle, elevator and progressive elevator trim were on the left. Although only one control on each hand could be activated at once, they were fully selective for the first time. . and this was the forerunner of what we now know as Tx Mode 1. Proportional control which gave more precise and trimable control on all control surfaces simultaneously was developed through the late 1960’s and is the preferred method of operation today.
The SMAE negotiated with the Post Office to obtain the first RC 27MHz frequencies, and a licence was required until 1963. The arrival of CB radio caused serious interference problems in the 1970s and eventually the 35 MHz band was obtained exclusively for model aircraft.
After the War there were two magazines in the UK covering model flying, Aeromodeller and Model Aircraft; the latter was initially “The Journal of the SMAE”, but later was available on newsstands. For a couple of years another magazine, Model Aviation, appeared spasmodically, with more of an American slant on model flying. US magazines like Air Trails, Flying Models and Model Airplane News were eagerly sought and read. In 1960 the first British magazine aimed solely at RC flyers appeared, Radio-Controlled Models and Electronics, followed later by Radio Modeller..
In 1950 the FAI introduced specifications for the free flight A/2 or Nordic glider, Wakefield rubber and power classes in the form of F1A, B and C, with three-man teams in each. Britain ran World Championships for the Wakefield rubber class at Cranfield in 1949, ’53 and ’58, and later the three classes together formed the World and European FF Championships, held in alternate years. By 1953 there were RC contests on the FAI calendar and in 1962 we held the second-ever World RC aerobatics Championships at RAF Kenley, with British flyers Harry Brooks and Chris Olsen in second and third places. As in all classes of model flying, competitions were the spur for development, as they still are, and before long the engines and RC equipment that was needed by contest flyers was available across the counter. As another example, at the 1966 Control-Line World Championships, held at RAF Swinderby, US speed flyer Bill Wisniewski won the F2A class at 166 m.p.h., using a tuned pipe exhaust for the first time, and gave a talk on this development after the contest. From this came both an increase in engine power and a reduction in noise.
The Cardington airship hangars are one of the world’s best sites for indoor free-flight duration and the UK ran World Championships for the F1D class there in 1961,’62, ’72 and ’86.