Tag Archives: Catapult

Catapult Glider and an old Squirrel

Experimental, , ,

I took a walk to the park to test out the Sparrow Catapult Glider (designed and built by Lloyd Shales).

These things are awesome! If you want one get in touch with me! The better flights are towards the end of the video.

I flew my old Squirrel too. This one is several years old as you can see by the numerous tissue repairs. 🙂

We also had the Chinese prefab catapult glider. We got it to fly by adding lots of reflex by bending the body quite a bit. Didn’t fly very well compared to the real genuine balsa flyer. I think a parachute would be simpler and work better.

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Folding Wing Gliders

Experimental

Brett and I did a test of a folding wing glider

I got it at Walmart for something like 10 bucks (end of summer sale).

It flew poorly. We could not get it to pitch up. It comes all ready to fly. I can see that they designed some wing reflex into it but perhaps because of flat packaging it wasn’t enough. I bent some more into it. It helped a bit but it still couldn’t raise the nose.

The construction methods are interesting. Very robust with the use of a fabric like wing surface and injection molded parts. Too heavy for rubber-power at this scale but just right for a toy catapult glider. Also the hinged folding wing worked fairly well.

There is a traditional type of folding wing glider concept by Jim Walker.  I added the patent pictures below. They have a DIY/kit over at make that I’d like to try. Bill Kuhl also has done some recent experiments.

I feel that there is a lot of complexity in the traditional design. So when I took a stab at catapult gliders not too long ago. I decided to not do a complex folding wing but instead try a spinning maple seed type descent. As it turns out, a spinning maple seed doesn’t work as well when you scale it up. They work but they don’t have the beauty since the efficiency seems to drop off. This is an awesome marvel of nature.

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First real model airplane project (age 9)

Chronology

When I was about 9 years old our family did a three year stint living at the mouth of the Moisie River.

At one point, my dad had to go away for 2 weeks (may have been a week) for a course.

I was pretty busy with my projects which included my Meccano set, macramé, , kite flying, acrylic painting (was taking courses on that), drawing, chasing girls, motorcycles (we had a Honda CT70 minibike!), playing with my dog Charlie, making my own inventions out of junk, imagining my own inventions that I could not make and much more.

But my dad felt he should get an extra project for me for while he was gone.

It was two model airplane kits. These were of high complexity using balsa and silk-span. He spent an evening or two sitting with me showing how to assemble balsa parts including cutting with a hobby knife, gluing, attachment of silk, shrinking of silk, doping, sanding and other finishing.

I got one of he models completed. It was quite a disaster. I remember that I could not get the center wing rib angle right for the dihedral joint. The covering was pretty sloppy. The wing root was not very strong. I had no idea about proper winding or trimming the aircraft. I remember being ready to fly the plane and my mother objecting saying that the wind was much too strong today (she was right). We all know how much this sort of thing means to kids. I insisted and went to the front lawn to try the plane. I wound it up and it did not fly. It pitched up and then fell back. I tried a couple more times and it kept pitching and falling back like a leaf. Today I know that it required a balast to get the center of gravity right. I tried it till the wing root failed. Perhaps five tries.

I was pretty pleased with this experience. I was now imagining a beautiful balsa frame with a perfect job of covering it with silk-span and imagining it could sail very high up. But of course my current project didn’t fly yet, but I intuitively knew that I would sort it out some day.

This really stuck.

My dad returned and after his assessment he produced some ready to fly catapult planes for my brother and I. We had a lot of fun with those over the next month or so.

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