The BMAA 1970 - 1976
Proper hang-gliders arrived in the Old World at the end of 1972, with a Californian machine which Christian Paul-Depasse brought into France and marketed under the name 'Deltaplane'. Hardly had the Deltaplane taken off, than Bernard Danis brought out his own version, the 'Delta Manta' which became the best selling hang-glider of its time in Europe. Hang-gliding developed as one would expect, with a number of serious or fatal accidents, caused by mistakes or foolishness - it is not for us to judge. But we would do well to remember Otto Lilienthal's dying words: 'This is the price of progress!'
Once again, designers followed the well-trodden aviation path of modifying what is basically a glider to accept a motor. At first they called the result a powered hang-glider, and only later did the terms ultralight and its FAI equivalent microlight come into use.
But before we chart the mainstream development of the sport, we must mention three early machines which are ultralights in spirit even though they have no hang-gliding roots - Bob Hovey's 'Whing Ding', Homer Kolb's 'Kolb Flyer' and Michel Colomban's 'Cri Cri'. All three designers simply set out to create a light, fun aircraft, and only later found that their machines were attracting ultralight enthusiasts. The American 'Whing Ding', which first made its appearance in 1970, is still available in somewhat modified form today and was the progenitor of a whole series of Hovey designs, though Bob's predilection for biplanes has limited their influence on the mainstream of the sport. By contrast, Homer Kolb's 'Kolb Flyer' was a tube and fabric ultralight in what was to become the classic American configuration, and its influence would have been enormous had this genial, modest man not flown it purely for his own and his neighbours' amusement for fully 10 years. Only in 1980, by which time it was no longer revolutionary, did the world realise what a gem he had produced.
The 'Cri Cri' is different again. It is not a microlight according to the FAI definition, but it is mentioned here out of respect for its unique appeal, as the smallest twin in the world. Unveiled in 1973 at the French 'Oshkosh', it was an instant hit, with its 139 lb (63 kg) empty weight, Plexiglas blister canopy, a low wing as thick as a handspan and tiny 16.1 (4.9 m) span. Power came from two 8 hp Stihl chainsaw engines, but thanks to its tiny wing area it can cruise at very non-ultralight speeds, around 125 mph (200 kph) being normal for the higher powered later versions. It remains a fascinating machine, but one aimed at conventional pilots and intended for normal airfields, rather than the fore-runner of the new ultralight breed.
That same year, however, that forerunner appeared, for Bill Bennett was following in Barry Palmer's footsteps and attempting to motorise a Californian hang-glider. It was treated by the media as a huge joke. Bill had coupled a 12 hp engine to a pusher propeller and mounted the package on his back. This was a seductive solution to the problem of powering a hang-glider: there was no modification required other than a supplementary harness; the pilot still launched by running, his motorised back-pack then acting like a winch to get him to greater and more useful altitudes.
It did not, however, work particularly well, as the prop was almost completely masked by his large back, and what little efficiency remained was further reduced by the thick wire guard with which Bill was prudent enough to surround the package. So while gliding Rogallos were advancing rapidly in America and elsewhere, it was left to the Europeans to take up the challenge of finding a practical method of motorising them. The Americans had other things on their minds, for they were about to begin their love affair with hybrid and later three-axis controls, an ardour which shows no signs of cooling right to this day.
Why did America power pilots turn so decisively to fixed-wings? Part of the answer is undoubtedly Volmer Jensen, a gliding enthusiast who began his career in 1925 by building a Chanute biplane from plans published in Popular Mechanic magazine. He was smitten for life by the rustic pleasures of weight-shift and hybrid controls, and in 1941 completed his own design for a downhill glider called the 'VJ-11' a strut and wire braced biplane in the Chanute style but with the addition of a T-tail. Later he built a light aircraft and a slightly heavier amphibian, but despite these side-tracks he remained throughout the bleak (for low speed flight enthusiasts) days of the '50s and '60s one of the few designers who never ceased to think in terms of sporting aircraft, especially those capable of being foot-launched and easily transported. But even he could not go against the current of history; his ideas were years ahead of their time and the '60s would be over before people realised the fact.
However, by 1970 the world was catching up with him. Jensen, by then no longer a practising aeronautical engineer, stumbled across hang-gliding at Santa Ana in California. He was inspired! He built a monoplane hang-glider with a cruciform empennage and a rudder and called it the VJ-23 Swingwing. It was particularly advanced for its time and with the technology of its day could only be constructed with difficulty, so it was followed in 1974 by the VJ-24 Sunfun. Like its predecessor this needed an engine (of around 10 hp) to get the best out of it, and in motorised form is still in production - a testimony to its designers farsightedness.
Across in France, the oil crisis had arrived. Hang glider pilots were finding travel to the mountainous regions a long and expensive business, while gliding enthusiasts too were hit, as the price of towing increased dramatically. Parisian architect Jean-Marc Geiser realised that if the Rogallo could be effectively motorised, 'hang gliding' from the flatlands would become a reality, and glider pilots too would have an alternative. He sat down at his drawing board in 1974 and chewed over the problem…
What emerged was to become the Motodelta: a happy marriage between a Danis 'Delta-Manta' Rogallo and what we would now call a trike unit, although unlike modern trike units this one incorporated a tail boom and fin/rudder assembly. Fitted with a 12 hp flat twin, this assembly first flew in May 1975, without any major problems, and represented a major advance. Constructed from glassfibre, polystyrene, polyester and epoxy, the 'trike unit' was suspended from its wing by a single streamlined mast and did away as far as possible with the spider's web of cables. No trapeze here - instead a single top-mounted stick was attached to the wing, the conventional-control theme being continued by fitting rudder pedals in the normal fixedwing position.
The French authorities were completely disoriented by this sudden apparition, for which they had no applicable regulations and which could land and take-off almost anywhere. The bureaucratic logic was inescapable: 'If it isn't a hang-glider - and it can't be, because it has an engine - then it must be a lightplane, and if it's a lightplane the pilot must have a license and the aircraft must be certificated as a homebuilt'. On top of all this, Jean-Marc Geiser is a perfectionist to extremes. A combination of careful development, bureaucratic problems, and a few mishaps, meant that the Motodelta didn't go on sale until 1982, fully seven years later!
By that time the trike proper was well established and within a few months production ceased, but there is a happy ending to the story, for the design has re-emerged virtually unchanged in Japan.
We do not know how much of the Motodelta was due to Geiser's inventiveness and how much he was inspired by others, but certainly he was not the only person thinking along such lines in the early 70s. Almost simultaneously with the Motodelta, a Daf powered trike-like device appeared in Italy, while a glance at Dan Poynter's 'Hang Gliding' book, published in 1973, reveals an aircraft carrying the number N4411 and consisting of a Bensen gyrocopter with its blades replaced by a Rogallo but with its rudder retained.
There were two other noteworthy French pioneers. J Duvaleix flew a tubular-construction hybrid-control machine very like a modern trike but with twin fins, exposed to the wash from the pusher prop, each with its own rudder. Between the fins was a monobloc elevator. Controls were conventional stick and rudder, though there was an element of weight-shift in its control system as the pilot could alter the angle of a trellis of tubes and cables. Behind the pilot, mounted to the wing support struts, was a 1500 cc VW engine of some 45 hp. No more was heard of this unique machine.
Even odder was the unfinished prototype built by Jean-Pierre Grammare. Beneath a Danis 213 ft2 (19.8 m2 ) Rogallo was suspended what we can only describe as a GRP sarcophagus, inside which the pilot lay flat on his stomach. This assembly was suspended from a triangular arrangement of tubes fixed to the wing and which also carried the main wheels of the under-carriage. Fortunately, Grammare never got as far as test-flying his 'Chrysalide', and in deference to his life expectancy turned instead to other homebuilding projects, which he has completed successfully.
Now for the first time since Cayley and his reluctant coachman-turned test pilot, an Englishman enters the story - Len Gabriels, founder of the Skyhook company.
Hang-gliding was growing strongly in the UK, and just as elsewhere pilots were getting fed up with hauling their gear up hills before take-off. Gradually the back-pack idea was discredited, and small wing-mounted power packs were substituted. These early experiments went largely unrecorded, even in log books let alone the press, because the pioneers were uncomfortably aware that the addition of an engine made the craft liable to registration and airworthiness legislation, and the pilot liable to licensing.
Foremost amongst these clandestine experimenters was Len, who himself cannot remember whether his first keel-mounted power pack was tried in late '73 or early '74 (his logbook being curiously blank at this point)! But, he does recall that the McCulloch-engined machine was not a great success, providing enough thrust to assist flight but not enough for a flat land take-off. One way or another, it didn't seem worth the hassle, and it was not until 1977 that he pursued the idea seriously.
But across the English Channel, French-men Maurice Bruneau and Dr Peres were thinking along similar lines, and early in 1975 mounted a 4 hp Flymo motor on their 'Delta Manta'. Near Paris that same year, Veliplane proprietor Roland Magallon was also hard at work, clandestinely testing various methods of powering his company's products. At first he fitted a triangular structure of tubes to his trapeze and tapered it back to support a 12 hp McCulloch engine at the end of this 'fuselage'. Later he replaced the engine with one of 15 hp, which drove its prop at a dizzy 9000 rpm, but he prudently concluded that it wasn't wise to market such a device, believing that it wasn't possible to make it safe. His interest in power remained, but it would be a few years before he would make his greatest contribution. The day of the trike was yet to come.
Meanwhile in the Antipodes, ultralighting had taken off, in every sense. The first flights of the Ron Wheeler's 'Scout' took place in May 1974, and the aircraft went on sale immediately, the world's first commercially available fixedwing ultralight (Bob Hovey's 'Whing Ding' was only offered as plans). Santos-Dumont would have been proud of it - a light aircraft reduced to the absolute minimum, a latter-day 'Demoiselle' with a conventional tail and relieved of its hotch-potch of wires.
The Australian Department of Transport were quicker off the mark than their European counterparts, and in 1976 created the first ultralight legislation, bringing the 'Scout' within the law and really opening up the market. One of the first to take advantage of this was Col Winton, who that year introduced his 'Cricket', a design as influential in its homeland as the 'Quicksilver' was to be in the US.
Back in America, things were really warming up. There was still no quantity production of ultralights, but a wide variety of new designs was appearing. At the '75 Oshkosh, for example, Larry Haig showed his extraordinary 150 lb (68 kg) 'American Eaglet' with 12 hp McCulloch engine, a beautiful ultralight motor glider which was featured in the first edition of this history. However, with its completely enclosed cockpit, it appealed more to licensed pilots or sailplane enthusiasts than to hang gliders, and it thus met with only limited success. Georges Applebay's 'Zia' was unveiled in its canard guise at the next Oshkosh, but this too remained more of a curiosity than a force in the market place. Well before either of these came the Birdman 'TL-1A' and 'TL-1B' by Emmett M Taly, an interesting design produced from 1976-82. In truth, however, none of these designs really launched the movement in the US in the way the 'Scout' had in Australia; that would have to wait until 1977.
Meanwhile, a Mormon from Utah called John Chotia had since 1975 been working on a two-axis ultralight which was to be a major influence on the growth of the US ultralight movement.