Discussion Le Pou du Ciel !

[Marcelo-Skyfly]

Hello from Canada !

Anybody knows where I can find plans to build the famous Henri Mignet Pou du Ciel ?
My idea is to make one out of Foam and electric powered.

Thank you very much !

[FLB]

HI,

It's not a plan for that plane but a webpage dedicated to it with different 3 views abd a lot of pictures. Hope it will help.

http://pou.guide.free.fr
http://pou.guide.free.fr/connaitre/hm380/hm380.htm
http://pou.guide.free.fr/connaitre/1...1959-sfasa.htm
http://pou.guide.free.fr/participer/...e_de_liens.htm


Sincerely.

FLB

[FLB]

Here it is. I found a nice plan of the Pou du Ciel. It is a bit small (FF size) but could be a good basis for an upraise plan. Email me and I will send it to you.

Regards.

FLB

[mignet]

Mignet Aircraft

[scoo2er56]

http://www.rcgroups.com/forums/image...ine=1240614108




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[mignet]

Do you know Barbapapou?

Behind this strange sobriquet lurks a voluminous beard (barb) whitened by the years. And behind that flowing beard, you find Yves Millien who was, from WWII to the 80's, a bard, a committed proponent, a missionary, an apostle of the Pou-du-Ciel.
I have spend hours on the telephone with him discussing the Mignet formula. An incisive – read sharp – author, he has written many pages for his ephemeral (alas!) pouducièlist paper entitled 'Our Aviation;' for Finesse 10, gone today; for 'Pilot privé' and for other aeronautical journals.
He was a fervent Pou-du-Ciel practitioner: he built and rigged them, flew them and voyaged all over France in them, even to Switzerland. He taught numerous pouducièlists. I benefited from his instruction, as débonnaire as effective, at the aéroclub of Noroît, otherwise called 'la Papouille d'Etampes.'
One day, in an HM-381, we continued a parachutal descent clear to the ground. With a burst of power at the last moment, the shock absorbers perfectly protected our respective sensitive derrières and the structure of the Pou-du-Ciel... There followed a roll of less than ten meters in practically no wind! What other formula could do as much?
He also opened an aeronautical bookstore on rue du Dahomey in Paris. During my Parisian escapades, I always stopped there. He always had something concerning the Pou-du-Ciel to sell that enriched my weak aeronautical baggage.
Then one day, no more! Vanished disappeared, no news of Millien...
What we didn't know was that his wife had an illness that handicapped her of which his reserve kept him from speaking. To be permanently at her side, he burned his bridges to the world of aviation.
He resurfaced recently: after ten years some saw him again at the fly-in at Saint André de l'Eure. I ranted against my job that kept me away from the gathering and the sharing with old friends. And then one of my clients, a wine producer at Pouilly and a friend, owner of I don't know what marvel of an ULM costing several tens of thousands of euros and also graced with a luxuriant beard, called me to say that he had met Yves and that I should call him on his cell phone.
That's what I did. If the years have whitened his beard and the flow of his words has slowed somewhat with age, his mind is clear and his memory accurate. He remains as acerbic and aeronautically incorrect as ever... That's what, among other things, attracted me from our first encounter in 1974. Today, while he is still a Parisian, I met him in the rustic decor of a dilapidated country house close to Nogent le Rotrou in the Eure and Loir at the beginning of October.
Barbapapou had wind of my purchase of an Airplume to restore (I'm a traiter to the pouchellerie!) and wanted to give me several warnings, little wishing that a fatal pitch forward accident should cause my wife to wear black permanently...
Flying entails a risk
To fly is not the natural destiny of man. In the air, he's no longer in his element! Before venturing there, he needs to remember this. If he's not willing to accept this fact, he'd be better off staying on the ground... and not hassle those who know and accept the risk but do everything possible to keep it at a reasonable level...
Each type of aeroplane dhas its danger zone. Even the Pou-du-Ciel risks entering an uncontrollable dive and flip onto its back when the front wing loses lift.
The Pou-du-Ciel and its dangerous dive
Why the vow of silence concerning the Pou-du-Ciel...when one can fly it with great security if everything is done with proper care (construction and rigging) and if the pilot is on guard? According to Yves Millien, the exceptional security of the Pou-du-Ciel at high angles-of-attack becomes insecurity at low angles-of-attack. He considers that the risk at low angles-of-attack is quite real, that it has killed many. However, it is possible to greatly reduce the risk with proper rigging and prudent piloting...
Yves showed me stability curves for the Pou-du-Ciel, zones of security, those that are hazardous, and those where the risk of an uncontrollable dive are high... He has gathered all the accident reports from the days of the original Pou-du-Ciel until the present along with observations of witnesses and of the machines after the accident along with his critiques of the machines he has tested before their accidents... The deaths where it is certain that the Pou-du-Ciel has not entered an uncontrollable dive are very rare...
I know, you will say that such a reversal by Millien is surprising for that ancient supporter of the formula! Yves has compiled a file that is nearly exhaustive on the Pou-du-Ciel and has validated his ideas in flight. It would be too bad if this precious research ends in the fire when he quits the planet... Don't forget that his knowledge of the aeronautical domaine is immense having worked in his youth in one of the companies that later merged to become Aérospatiale.
He believes the conspiracy of silence of the supporters of the movement (Henri Mignet included) has damaged the Pou-du-Ciel more than it has served it... He takes up arms against the pigheadedness of Mignet, who, even after the warning afforded by instability demonstrated in the first wind tunnel tests, didn't encourage the amateurs to use less risky cg placements.
In his Pou-du-Ciel, in the wind tunnel at Chalais-Meudon, Mignet was unable to avoid pitching onto his back! Robert Robineau, his faithful collaborator, payed with his life for the decision to recommend a centrage too far in the rear. Why the determination to proceed thus?
 centrage in the rear significantly improves the rate of climb for the Pou-du-Ciel
 the Poux-du-Ciel of that day were very under powered (17 hp for the Aubier Dunne) and didn't take off, or did so with difficulty with the normal centrage
 the original wing profile, with its pointed beak, had minimal aerodynamic efficiency which decreased even more the performance of the Pou-du-Ciel
Yves Millien has experienced in flight two cases of zero lift on the front wing of an HM bi-place. He says that it can occur brutally in turbulent air, which was the case each time.
In one case, Yves, adept at the digestive siesta in flight, was startled awake by the phenomenon! His student, in a panic, pushed on the stick...which was quickly over-ridden by Yves who pulled the stick to the rear and chopped the power. Once the danger had passed, he told his student that if the situation had become irreversible he would have strangled the student before impact!
The unfortunate student had received earlier instruction in a standard aeroplane...which caused him to react in the way he did and which could have been fatal for them!
Naturally, at that time, Mignet ordered Yves Millien not to talk of these two incidents in order not to discredit the Mignet formula. His public image certainly would have suffered because it had not yet recovered from the after effects of the initial accidents.
Louis Cosandey, the Swiss pioneer of the Mignet Formula, with whom he was closely associated, told him of at least two pitching incidents with his Pou glider during turbulent conditions. By using his flaps (and having sufficient altitude since he took off from high mountain pastures) he was able to recover each time. In one case the recovery was so violent that he was afraid he might lose his wings! But he survived... And there too, following the old precept that «flies don't enter a closed mouth», the pouducièlist vow of silence closed the matter.
In the east of France, a Criquet also experience a dramatic loss of lift in the front wing. The builder had increased the movement of the front wing beyond that in the plans: with the stick clear forward the front wing was at -8° rather than the -4° prescribed by Croses. He also mass balanced the front wing control to compensate for its weight on the ground. Finally, the centrage was 100 cm from the leading edge rather than 90 cm as on the prototype. During stall practice with his instructor, the builder experienced a violent loss of lift in the front wing with the stick clear forward. The machine flipped forward and onto its back with a brutal loss of altitude (approximately 200 meters). The control rod for the front wing was broken. Returning to normal flight, the instructor was able to regain partial control of the Criquet and to land in the country without incident.
Others, according to Millien, have also experienced similar misadventures (flipping to the front), some survived and some died. In the end, the log of the martyrs of the Pou-du-Ciel is not complete.
Yves has documented most of the mortal accidents with the Pou-du-Ciel: those who saw the accident generally describe the fatal pitch forward. For those accidents without witnesses, often, the condition and the position of the wreck leaves little doubt to the cause of the crash.
But that must not be said and still less written...
Fly in security in the Pou-du-Ciel
Alas, one fears that the next mortal accident in a Pou-du-Ciel will occur after a fatal pitch forward! How can one evade that, if not by summarizing the counsels of those who are prudent and knowledgeable?
In case of known longitudinal instability, the stick will be progressively less responsive, or not not at all, or worse, will respond in the wrong direction. In case of such instability, immediately reduce the power, pull progressively and slowly on the stick and add up flaps on the trailing edge of the rear wing. In no case, push forward on the stick!
The best precaution, however, is anticipation:
 construction and rigging: respect the plans of the designer
 movement of the front wing: conform to the prescriptions of the designer; limit mechanically the forward movement of the stick to avoid zero or negative lift; don't set the rear wing at too great an angle
 initial rigging: the charge on the front wing in kg/m2 compared to that of the rear wing, between 1.4 and 2, ideally between 1.6 and 1.8. Less than 1.4 and the front wing will too easily arrive at zero lift. Within this range, the Pou-du-Ciel performs well and is secure at low angles-of-attack. This rule should be firmly respected
 centrage: definitely needs to be verified in case of unusual configurations, for example, if the pilot or passenger is heavier than usual
 rear flaps: indispensable for the counter torque they create in case of the fatal pitch forward. The ideal is to have their control on the stick using a command such as the lever for the brake on a bicycle (the access to the levers on the Criquet is too long according to the designer of the Criquet cited above!)
 an elevator on top of the rudder is an alternative strongly recommended by the Argentine pouduciélists
 stick movement: block forward movement of the stick to avoid creating zero or negative lift
 flying in turbulence: reduce speed and power, the Pu-du-Ciel is safer at high-angles of attack rather than low... if needed, land
 stall (maximum angle-of-attack, I know, a Pou-du-Ciel doesn't stall, or very little...) or to stop a parachutal descent: never push the stick forward as in a standard aeroplane, just lightly ease off on the stick to return to normal flight
 ballistic parachute: strongly counselled, at least in a bi-place
To finish, paraphrasing Daniel Dalby, the designer of the Pouchel, build seriously and fly with care!

[mignet]

Mignet Aircraft