Published in 'Model Engineer' in 1909, this 18 in. span model with a "heavy cardboard" wing and 9 x 7½ oak propeller, weighing nearly 2 lb, was claimed to have flown for eight minutes. The builder also claimed an O.O.S flight with a 12 sq.ft model carrying a 6 lb accumulator.
In an issue of 'Model Engineer' dated October 21st 1909, there appeared an account of an electric powered free flight (F/F) model which, it was claimed, had been constructed and flown. The validity of this claim was questioned some 48 years later by the renowned Colonel H. J. Taplin, who on the 30th June 1957 made the first officially recorded electric powered radio controlled model flight. Col. Taplin was prompted to offer £100 to anyone who could produce a replica of the 1909 model and make it fly.
Electrical power for the Col.'s model was supplied by 25 silver/zinc cells weighing a total of a little over 28oz. Motor weight was 30oz. and the total model weight 8lbs.
|The interior of Col. Taplin's Radio Queen. The forward bay holds a hard-valve receiver, suspended on its side by rubber bands, with HT & LT batteries beneath. Next are the banks of silver-zinc cells with, behind them, an E.D. clockwork timer mounted above a three speed controller, the timer providing an overall shut-off if the radio link failed. Just in the bottom of the picture is the clockwork escapement, connected to the rudder by two external cords, which was the only other control.|
|The 30 oz 24v government surplus Emerson motor which on 30v and 8 amps would lift the 7 ft, 8 lb model off a smooth runway. The model was the seven year old Radio Queen prototype, normally flown with a 3½cc dieseL|
Further developments in the field came from the great German pioneer, Fred Militky, who first achieved a successful flight with a F/F model in October 1957 using a special motor.
'Silentius' by Fred Militky.
In February 1959, a Dr. Ing. Fritz Faulhaber walked into the offices of the German magazine 'Modell' and enquired if a motor he had developed for use in remote controlled camera shutters might be of use in modelling. This was the now famous Micromax, a coreless motor with integral gearbox.
With this motor, Militky developed a series of designs for the Graupner firm which brought practical electric flying models within the reach of the average modeller. (See drawing of 'Silentius' above).
At this time, the nickel/cadmium cell was still to appear and batteries used for these early flights were either small sealed lead/acid batteries (accumulators) or salt water activated cells.
Militky went on to develop lightweight R/C models, then the more sophisticated Graupner 'Mosquito' and 'Hi-Fly' designs and was to play a leading part in the design of a man-carrying electric aircraft.
The late Fred Militky with his 'Hi-Fly', the starting point for the
first manned electric plane, the 'MBE 1'.
Following a lull in the commercial side of electric flight, 1972 saw the introduction of the Mattel 'Super Star'. This ready formed plastic and foam aircraft was powered by a Japanese Mabuchi motor taking its current from two fast charge nickel/cadmium cells. A novel feature was the inclusion of a cam, gear driven from the motor, which moved the rudder and gave a degree of flight programming. Recharging was accomplished by connecting the model to a 6 volt zinc/carbon 'lantern' battery.
The Mattel 'Super Star' appeared in 1972, a plastic and foam free-flight model with cam programming.
Gear reduction was a feature of the Mattel power unit.
This principle was continued in the Mabuchi A.1. power unit which appeared in 1974. Here provision was made for the modeller to adapt things to his own requirements, with the 6 volt charger being fitted with 4 - U2 ('D' size) batteries and the nickel/cadmium cells being removed from the power unit for charging. Unlike the Mattel unit, however, the propeller was driven directly rather than via reduction gearing. This unit is still available. At this point, numerous units began to appear from Japan, Germany and the USA. These catered for almost any type of model from small F/F aircraft to large R/C models.
The Mabuchi A 1 power unit, first seen in 1974, with its charger,
using dry batteries to charge the flight nicads.
While development continued in these countries, Britain appeared to lose interest. The advent of almost-ready-to-fly models such as the Nitto 'Kitty', Kyosho 'Sportavia' and Acoms 'Cessna' did little to improve the situation (In fact the 'Sportavia' is still unknown in the U.K., while only small numbers of the 'Kitty' were seen) and only a small band of enthusiasts still persevere.
One of the early radio control models commercially available for electric flight was the 'Electra-Fli'.
In Europe, electric R/C models have gone from strength to strength with numerous contests being held for duration, aerobatics, pylon racing, scale etc. Motors using samarium cobalt magnets and fed from 30 or more cells have produced performance levels nearly equal to models powered by internal combustion engines.
Fortunately, in the 20 years since the above was written, things have changed dramatically.