History and Future of the Altigenerator

Clowns are sometimes the envy of others, but don't expect any compliments!


The crash.

It is 6:30 pm on August 17, 1984. The soaring flight on the cliffs of St Pabu between Erquy and Val André in the laminar wind facing the ocean is intoxicating. The altimeter after two passes along the cliffs of Saint Pabu indicates 320 meters.

I was hoping for more with 8m/s at take off but now it’s time to think about landing as night is near. The sun is setting on the horizon. The white crests of the waves pushed by a steady 10 knots North-East wind, the only indicators of the wind strength and direction, are less and less visible. The DSTI La Mouette profile with the famous pif-paf is a real treat to fly.

Perfectly tuned, this wing allows me to be always above my colleagues. The wind seems to be weakening. My hang glider friends who took off earlier have already landed on the beach, they have folded their wings and gone to reserve a table in a crêperie where we are to spend the evening together. I declined the invitation to have my car « lowered » near the beach.

The field near the take-off slope is a tempting place to land because my car is parked there. Landing in this field would avoid a good half an hour of jogging on the customs paths to get my old 4L back. This landing place has a bad reputation but each time I used it everything went well so with a little less wind there should be no problem.

To lose altitude I start a big circle over the sea and the nearby campsite. Without going too far back from the ridge so as not to get into the rollers caused by the cliff, I pull on the control bar to gain as much speed as possible in order to be able to cross the possible turbulence without stalling. As I skim the tops of the cypress trees on the approach path I notice that my ground speed is not reducing as expected and on my left side I catch a fleeting glimpse of the broom trees overhanging a steep dihedral exposed to the East. The wind has not weakened but has in fact turned 45° to the East. Realising my mistake I immediately released the pull on the control bar and turned right to head for a pass and dive back to the sea. Too late a lateral roll puts my wing in a dive, a dull pain in my whole body and nothing more… It is the calm that woke me up. It’s night time, the greasy earth of the recently ploughed field a few centimetres in front of my eyes smells strongly of humus and mould. The stars in front of my eyes dissipate into small, fleeting fireflies. Events slowly take their place in my mind. What surprises me is the absence of pain and also my left hand, it should be in front of me, it should even be in front of my forehead but it is not. The pain comes as soon as I try to move. My left humerus is broken and my left arm is behind my back. By wriggling I manage to get off the wing and drag myself to the neighbouring farm. Then it’s the classic pattern: Val André fire brigade, Saint Brieuc hospital emergency room, operating theatre…


A long and painful period devoted to recovering my physical abilities was the programme for the end of 1984. The spiral fracture of my left humerus disconnected the radial nerve. My right arm is paralysed: my right hand is as good as dead, it remains dangling and useless.

« No, you don’t get depressed because you won’t stay crippled », easy to say when everything is going well. To join the useful to the pleasant, it was necessary, the will only works by stimuli. Invalid for any work. I was even forbidden to drive my car with my only valid hand. Electrotherapy was my salvation. I had to continue to operate all the muscles that I could no longer control. With the help of a physiotherapist friend, we defined a battle plan for two hours a day where I mobilised all my willpower to bring my left hand back to life in his office. The rest of my time was spent in the workshop in my garage completing my rehabilitation.


As a child I was a fanatic of Jules Verne, then it was Henri Mignet and his « Poux du ciel » who fascinated me. Anyone could build a plane in their garage with pieces of wood. My parents had to hide all the pieces of wood and forbid me access to the workshop. My big dream was to fly over my house with an aircraft of my imagination. The first prototype was a kind of bi-turbine resembling an autonomous diving suit. Lying down in a prone position, this bi-turbine would push me forward like « Batman ».

Paris November 84. The Internet did not exist at that time, but the equivalent of tracing research in a specific field led to the INPI’s file of inventions. Several days were spent consulting the microfiche. A formula entered between two lines caught my attention:

F = M/f. In plain English: the power needed by an aircraft to zero (maintain its altitude) is equal to its mass divided by its glide ratio. So, weighing 70 Kg, if I add my wing and a 30 Kg propeller: that makes 100Kg. A delta wing with a glide ratio of about 10 (able to fly 100 meters from a height of 10 meters). With 10 kg of thrust I fly, with 11 I take off!

The Biturbine often brings the gendarmes to the house because the tests take place in the yard. The machine is attached to a table and the table is attached to an apple tree. A scale fixed between the table and the apple tree gives me information on the thrust obtained. I then start the engine and run to hide behind a wall. From this protected place I control the accelerator. At the third explosion of the fairing, while the debris still falls on the neighbouring roofs, I know that I have reached the end of the patience of my neighbouring friends.

The turbine does not lead to anything satisfactory. I relied on the effects of the vortex at the end of the small propeller blades to obtain additional thrust, but this vortex creates such a deformation effort on the tunnel that this gain in power imposes a structure that is too heavy to ensure sufficient rigidity.

Back to square one. Why not fly upright with a simple propeller on your back. In a school slope, the flight is done standing up during the very first flights. Once upright, why tip your head forward when the control bar is a perfect footrest. I have tried all the best free flight harnesses. In search of the most comfortable. After a few hours, the lying position always becomes a real torture. The thoracic cage is under pressure from the pilot’s weight, accentuated by the jolts of turbulence. The cervical vertebrae also work very hard because in addition to the head there is the helmet to keep horizontal.

The first prototype is a large tennis racket. The engine in the middle of the racket, a canvas seat in front of it, a propeller behind it, all hooked to the wing beam by the end of the handle.

So I arrive at my friends’ delta club in Erquy with my blower racket. I demonstrate garden cleaning by propelling dead leaves from their garden into the neighbour’s garden. Unanimously they look at me with a saddened condescending air and say: « Serge, stop your nonsense ».

At the end of their arguments, which are very logical by the way, it is impossible for them to erase what is already flying around in my Breton head. The date, time and place of the first take-off is fixed by consulting the tide directory: The next big low tide. Well, they decide, since you insist, we’ll bring in the TV!



This morning there are indeed 3 km of smooth beach in front of me. Almost no wind. The TV is replaced by a camcorder but they are my friends and one of them Bertrand is a doctor.

At idle, the vibrations of the JPX 212 engine make me see trouble due to the combined effects of the low inertia of the 45 cm diameter propeller and the too stiff block silents. With full acceleration the comfort improves but the 12 kg of thrust seem ridiculous compared to the noise. Facing the sea, the wing is very horizontal. The pitch and roll control is very smooth as the wing is perfectly balanced. I let the wing go forward, holding it back less and less. I feel the wing sit on its air mattress, I let it choose its incidence and feel its mass progressively decreasing then I am lightened by my own weight. The strides I take on the ground are only symbolic, just in case I have to carry again. In fact my feet are already 50 cm and then one metre… above the ground. To be on the safe side, I maintain this altitude by pulling slightly on the trapeze struts and thus gain a little speed. I’m at an altitude of about ten metres. Without even realising it my feet have found their place on the control bar, the sea is approaching. I let it rise gently and start my turn over the first waves. There is not a ripple on the water, not a turbulence in the air. I would like to extend this ra dada to the waves, this impression of being able to walk on the water is new compared to free flight.

My friends are there in front of me as I walk up the beach towards them, I let my wing do its thing, I feel that it is won. I arrive on top of them with about twenty meters of altitude then I head towards the cliff to recover the dynamic ascents.

I must be at two hundred meters when my engine stops, the two litres of gasoline were consumed. Any change in a test flight provokes a small pinch in the pit of the stomach, the nose of the wing drops a little and we wonder what will follow, then the usual calm of free flight gives me confidence. With this unusual engine I was hardly feeling my way around the controls but here under my wing without this noise I am in my element again.

The efficiency of the piloting is staggering. A free flight harness is attached to the wing’s keel by a strap. Pushing or pulling on the bar does not directly shift the pilot’s weight as the body often gets in the way in the control triangle and minimises or even annihilates the effectiveness of the pendulum effect. Under the Altigenerator, the keel-harness connection prevents the harness from pivoting on its vertical axis and all the pilot’s actions are immediately followed by their effect.

I don’t dare to go as far as the stall, but I can’t resist as the control response is so clear in a few tight 360° turns. One doubt remains: the landing. In free flight you finish the landing by pushing hard on the trapeze struts in order to give the wing a very high incidence quickly. With my motorised harness the pitch angle is very much reduced. I am therefore afraid that I will have to perform a frantic cavalcade before stopping the wing. Moreover the wing is a competition profile « La Mouette » and like any DSTI it has a speed range that my little legs will have difficulty in spreading out. In fact the landing despite no wind is almost a walk in the park 3 meters in front of the camcorder. The improved efficiency caused by the rigid connection of the harness to the wing keel is as valid in roll as in pitch.

The wing is stopped as soon as you push on the struts much better than with a conventional harness. In fact, it is enough to come to a pitching position at one meter from the ground and then to let the wing slow down by pushing progressively to refuse the landing before the feet touch the ground.


Two prototypes followed each other to end up with the structure I still use today, with the Solo 210 cc engine I got 2m/sec of climb rate.

Living in a summer resort by the sea, aerial photography was immediately open to me. My neighbours were so intrigued by my work that they encouraged me to photograph their houses from up there. This very lucrative activity motivated my focusing efforts considerably.

A series of 20 structures were made. 17 were sold. The Altigenerator was presented at most aeronautical events from 1987 to 1991. To prove the performance of the system, a French distance competition in the motorised foot-launch category was held. The French Microlight Federation even judged the Altigenerator worthy of appearing on its promotional brochure.

From 1990 to 2004 my professional activities made me travel a lot. I always carried an Altigenerator in my luggage to see from above the landscapes I was discovering. I then took my Altigenerator on a sailing boat and headed for Los Angeles. By combining business with pleasure, I realised my second dream: to combine the sea and the sky with my everyday life. « To « beach » my boat at high tide and to have all the beaches of the world to take off and land next to my boat house, to fly over from a great height or from a low angle this mirror which reflects on both sides the happiness inaccessible to the man too earthly, this is really the plan of my life.

The Altigenerator opened many doors for me, first in the United States where I was invited to fly on many sites and aeronautical events, then in Mexico where the government hired me to photograph the entire coastline from San Diego to Ensénada to make an environmental point. In British Columbia the real estate speculation was very demanding for aerial photographs that I could take at low altitude. I then had the unique opportunity to unfold and fly over a large number of paradisiacal sites in the Pacific before arriving in New Caledonia; my current residence.


In 2004 I used the possibilities of the internet by publishing a set of plans to answer the request of many enthusiasts.

Plans were sent to all countries in the world, but the objective of this approach was not achieved. Of course, the worst fear I had was to contribute even indirectly to an accident. To this day, no one has reported to me any incident that resulted in personal injury through the use of an Altigenerator. The Altigenerator is very forgiving. If the device is not perfectly centred it is impossible to take off. It is possible to bend the tubes, but nothing more. The feet-first, body-strapped position in the middle of a cage of tubes and cables is very secure. What I deplore is that the recipients of my plans too often want to redesign the Altigenerator and end up with strange and uninteresting machines. This phobia of always wanting to add wheels when all my energy consists of removing them, of wanting to add when I am struggling to remove and define the minimum necessary to finally be free in the sky…

The objective I have set myself since the first flights is to explore the limits of the Altigenerator system to define the right compromise.

– The reduced
Several Altigenerators equipped with a propeller speed reducer have been marketed. Although the reduction in noise and the increase in propeller thrust have brought a significant improvement, a reduction gearbox requires a more significant transformation of the wing to use a larger propeller.

– Fairing
At the request of a customer we made a fairing allowing to have the instruments under the eyes and the feet warm as in a real plane.

– Front beam replacing the rear cables
We then explored the solution of removing the rear cables from the wing and replacing them with a front beam. This allowed the instruments to be mounted in front of you on the beam and to get around the limitation of the diameter of the propeller imposed by the presence of the rear cables.

– Electric
For the past two years we have been building an electrically powered prototype, which is now complete. We are carrying out the first flight tests. All these options have the merit of being able to be combined and why not envisage a reduced electric Altigenerator without rear cables. However, let’s not forget the basic rules: the Altigenerator must be light and for that it must remain simple.


Today, with the paragliding market running out of steam, the hang-gliding market could take off again if it is revived. The obvious solution to all the disadvantages of hang-gliding is auxiliary propulsion to individualise the activity. Auxiliary propulsion dispenses the hang glider from collective structures such as bases, listed sites, springboards, recovery vehicles…it opens access to a multitude of new sites and unique flight plans.

I’ll be 73 in October and I’m waiting for my new Ellipse wing to test my latest electric prototype…

Wing manufacturers, think and work together, I am at your disposal.

Serge Bessault