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Old May 13, 2004, 05:12 PM
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Info on Macreadys pterosaur?

Does anybody have any information on the 1/2 scale pterosaur made by Paul Macready in the 80's? I believe its the same one in the movie "War Games". I have looked all over google and can only find vague references to it. Thanks.
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Old May 13, 2004, 06:46 PM
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Macready Pterosaur

Nihil , Goto :
http://www.rcgroups.com/forums/showt...3&page=1&pp=15
http://ovirc.free.fr/McCready.php
Robert Korobelnik
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Old May 13, 2004, 11:38 PM
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MacCready's pterodactyl was not the model used in the War Games movie.
The one in the movie was a fixed wing glider with a movable head. I have no idea who created that. Possibly one of the movie studios.

War Games came out in 1984, the same year the news broke in RCM about the MacCready project but the project was just mid-way then and not near completion. I remember it well. I then waited and waited to hear about the status of the project but it wasn't until 1985 or 1986 until the model flew.

The pterodactyl project was produced by a grant from the Smithsonian and the main purpose of the project was to film the model flying for an IMAX film called "On the Wing". I recall in the 1984 article the project was granted $100,000.00. I remember that being an inconceivable amount of money at the time and feeling sick with both disbelief and envy.

The pterodactyl did not really qualify as an ornithopter because it could not sustain flight. It was towed into the air by a van along with a stabilizing tail appendage that dropped off in flight. It had a sophisticated onboard stabilizing computer which had to be activated before the tail appendage dropped off. Then, the flapping commenced and it flapped its way through a glide to the ground.

The flapping system was powered by two Astro cobalt 40 electric motors on God knows how many big heavy ni-cad batteries! The bird weighed more than 40 pounds! The flapping mechanism was not cyclical but recipricating, with the motors reversing direction at the top and bottom of each stroke. The motors used cog belt pulleys coupled to a ball screw jack system made of composite materials.

To this day, I have no idea what they made the wing membrane out of.

Pitch control was accomplished by a system that moved the main wing spars fore and aft changing the CG. Roll control was managed by moving "fingers" out on the wings that acted like spoilers. Not sure about yaw, but I think the long beaked head moved side to side. All of these functions were computer stabilized.

Although I think the filming of the model (which was done out at the Bonneville salt flats) was a success for the IMAX film, later there was one unforgettable PR nightmare for the MacCready team and that was at some exibition where the Pterodactyl suffered a most embarrassing crash..I think it was at the opening of the Mid-America Mall or something but it was all over the news. I recall seeing the event on the news. They model had been towed up and right upon release it went into a violent "lamshevak" tumble and plummeted to the ground totally out of control. I felt really sorry for them.
They blamed the problem on the onboard computer malfunctioning.
The tow van was then seen rushing to the scene lof the crash like an ambulance to a plane crash. Really embarrassing and on national news!

I think the pterodactyl was rebuilt for display at the Smithsonian and it's there today. I never saw the IMAX film but I certainly would like to.

Sean
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Old May 14, 2004, 02:51 AM
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thanks for all the info guys. I am thinking about building my first flapper, and though the bird shaped ornis look great, the pterosaur has completely grabbed my attention. I have found that the MacCready ptero used a Liebeck LPT102B airfoil at both root and tip, but winfoil knows nothing about this airfoil, and I am not sure where to start. Any suggestions?
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Old Aug 09, 2014, 08:00 PM
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An old thread, but interesting. Paul was a friend, and gave me some of his in-house calculations and trial video for his QN project. He used Astroflight 60's to power it. Had he used paired 40's, it would have maintained level flight. The 60's wouldn't reverse and accelerate fast enough to achieve the flapping rate required by the living animal, but the 40's would have. The weight of his replica was pretty close to that of an actual Quetzalcoatlus of that size.

His budget was about $550,000.

His wing "membranes" were semi-rigid with compression battening instead of tension and were not intended to emulate Pterosaur membranes. Aileron control of the replica was at the wrist by means of a mortise and tenon joint between the location of the distal carpal and the 4th metacarpal.

The Washington crash was due to the neck breaking under loads incurred during the winch launch.
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Old Aug 09, 2014, 09:16 PM
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Quite the necro-bump, but I'm glad you did. Do you still have any of his data? With more modern technology, it should be possible to make a properly flyable pterosaur.
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Old Aug 09, 2014, 10:04 PM
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I still have his data and in-house video, though it is quite outdated now (it is still a remarkable body of work anyway).

Personally, I'm far more interested in the smaller morph (Quetzalcoatlus species, 15.75 foot average wingspan) than I am in the big guy (Quetzalcoatlus northropi, 36 foot wingspan).

A full scale Qsp would span about 4.8 meters and weigh about 20-21 kg. The fossil remains are far more complete for Qsp than for Qn. A full scale Qn would weigh about 150 kg.

The biggest problem in building one that flies properly is in emulating the properties of the brachiopatagium (the wing membrane). Materials technology isn't quite there yet.

Flapping frequency for Qsp is about 1.65-1.85 Hz. For Qn, it is about 0.9 Hz.
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Old Aug 10, 2014, 12:26 AM
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There is some info guys
http://ornithopter.de/daten/maccready_pm.pdf

http://pterosaur.stanford.edu/Propos...escription.pdf


http://ornithopter.de/daten/maccready_bunte.pdf
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Old Aug 10, 2014, 07:29 AM
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In the first link, the fingers in the detail photo captioned 'Drei bewegliche', the fingers are mounted backwards. They are oriented correctly on the adjacent illustration, but both images show them on the antero-ventral (front bottom). side of the wing. They were actually on the antero-dorsal (front top) side.

Paul's QN replica flew with an impossible 'broken' neck configuration in order to shift the head further aft (Paul knew this and did it to reduce the destabilizing effect of the head in flight).
The attached illustration shows the maximum deflections possible without breaking the animal's neck. Note that the neck in the profile view is in neutral position, not flight position. Flight position was more swan-like. Also notice the difference in the shape of the head.

BTW, the uropatagium (hind limb membrane) in the attached illustration should attach slightly further aft on the biological tail. The hind limb membrane flew in upload configuration carrying about 85% of the weight of the hindlimbs. Cruise lift coefficient of the tail was about half that of the wings.

To create a yawing moment, you drop one leg at the hip. The head was not used as a primary rudder. If the neck is deflected right, the head will usually be simultaneously deflected left to minimize the yawing force.
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