New Glider to Soar With Sails (Aug, 1929)

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New Glider to Soar With Sails

THE WORLD’S first sailplane, something new in gliding, has just been constructed by John Demenjoz of Bridgeport, Connecticut. This novel glider represents nearly a year of work. It has a 40-foot wing spread, is 30 feet in length, and altogether weighs less than 600 lbs.

It has no motor, and is to be propelled by wind only. Mr. Demenjoz is shortly to take his machine to Old Orchard, Me., where he will make it the location for the crucial tests of his new invention.

Original in his idea of making a plane go both ahead and into the air by the use of sails similar to those of a boat, the French inventor has carefully calculated all the requirements of stability, he says, and is confident that with a wind of 20 miles an hour he should be able to fly. He further predicts that he will be able to fly as high as there is any wind. He estimates his craft will attain a speed of 40 miles an hour.

The principle of making sails propel vessels and vehicles other than boats has been widely applied in the past to railway handcars, road wagons, and the like.

To the editors of Modern Mechanics, however, who are watching the forthcoming trials with much interest, it would seem that a more logical way for the application of the sail would be to have a counter sail under the landing carriage to balance the high center of effort of the present mainsail. This could be folded, and unfurled when in flight to add to speed and stability. That is, of course, providing the principles are sound and the glider actually flies. At all odds the inventor is to be complimented for his innovation and for his enterprise.

  1. Jari says: May 3, 20118:46 am

    What next? A flying schooner?

  2. vse says: May 3, 20119:29 am

    Wow! Even in 1929 there should have been plenty of guys around knowing their physics well enough to predict that this will not work. Probably everyone ever having operated a sail boat?

  3. Toronto says: May 3, 201110:42 am

    Think of the size of the daggerboard!

  4. Tim says: May 3, 201112:45 pm

    Here’s a short write-up of the test:…

  5. Jari says: May 3, 20112:47 pm

    Toronto: I was thinking of 400kg lead core keel 🙂

    Tim: I’m surprised that the thing get to be airborne without flipping over in slightest crosswind.

  6. John says: May 3, 20112:48 pm

    Tim: That was an excellent find! Thanks.

  7. Hirudinea says: May 3, 20113:01 pm

    This reminds me of Christopher Columbus’s first airplane.

  8. Timaay says: May 3, 20118:04 pm

    Looking at these old articles one gets the impression that the editors would print anything with a picture. I mean, were we really that stupid back then or were they just that desperate to fill their pages? I’ll admit it’s an interesting story and a nice build-up, but a little level headed commentary from the editor would have kept me from scratching my head and wondering if it was a joke or not.

    Hirudinea, your comment made me laugh.

  9. Timaay says: May 3, 20118:13 pm

    I’m not an aeronautical engineer, but I do know how an airfoil works. The air must pass over the wing in the opposite direction of travel. In order for the sail to function the air must push against the sail in the same direction of travel. The wind can’t blow both ways at the same time! The whole thing is ridiculous for crying out loud! Oh, I give up!

  10. John says: May 3, 20118:32 pm

    Timaay: Back then? Never heard of Polywater, Fleischmann’s Cold Fusion & Archaeoraptor, the MMR vaccine controversy?
    And before you get too smug remember all of those stupid, unsupported e-mail myths that everyone keeps forwarding

  11. Cristian Raicu says: May 4, 20113:47 am

    If you want to build this:

  12. Cristian Raicu says: May 4, 20113:59 am
  13. Charlene says: May 4, 201111:45 am

    Timaay, the editors often would print anything that had a picture attached. Often they’d find an appealing picture and write an article to match. Hence all the stories about items for “milady” that were really excuses to get pictures of pretty girls into the magazine.

    Not that there’s anything wrong with pictures of pretty girls, but it isn’t always easy to get them into Modern Mechanics without a little creative editing.

  14. Frauke says: May 21, 20114:54 pm

    see the 100th anniversary at the Wasserkuppe. And in 1929 sailplanes flew already at the west coast

  15. Stefan says: July 30, 201110:26 am

    … well, that was never going to work. Seriously skewed basic knowledge of physics on the part of the designer.

    Besides, that ain’t no glider or sailplane. Those work just fine. Have done ever since some time after Otto Lilienthal died trying.

    My personal favorite when it comes to crackpot aircraft:…

    That one even has a perpetuum mobile wrapped into it. Wont’ work, either. It’s the laws of nature … 😉

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