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blackshire
05-14-2009, 05:15 AM
Hello All,

This week I found the web site for the "resurrected" company called American Junior Classics (see: www.americanjuniorclassics.com ), which produces unusual "double-folding-wing" catapult-launched gliders that were pioneered by Jim Walker, the founder of the company. (He also invented the Control-Line model airplane and developed sound-controlled gliders years before R/C model airplanes appeared.)

The "Plain Jane" and "404 Interceptor" folding-wing gliders (see: www.americanjuniorclassics.com/ajstore/planejane.htm ) look like they could be readily converted into boost-gliders or rocket gliders. In both gliders, the wings are rotated 90° at their roots, then are folded rearwards (flat against the profile fuselage) for catapult launch. The airflow keeps the wings folded flat during ascent. As the glider slows down, a rubber band first unfolds the wings and then rotates them back into glide position.

For a boost-glider or rocket glider conversion, the pop pod (or motor pod) could have a small "slide-away" clip that would hold the wings flat and prevent them from fluttering during the rocket-powered ascent. When the pop pod separated (or the motor pod slid backwards, in a rocket glider conversion), the clip would slide off the wings and allow them to unfold.

In addition to using motors with shorter delays, it would be prudent to use a stronger rubber or elastic band to ensure that the wings would unfold in the event that the model coasted past apogee (perhaps due to weathercocking) and the motor's ejection charge fired when the glider was falling at a significant airspeed.

I hope this information will be helpful.

gpoehlein
05-14-2009, 07:27 AM
A lot depends on the balsa these guys are made from - The cheap hand-launch gliders I've seen in the stores use such light balsa that they will shred on anything more powerful than a 1/4A (Ask me how I know! :rolleyes: ) You might trace out the parts on higher quality balsa and then build it.

Greg

Mark II
05-14-2009, 08:19 PM
Double-folded wing, folded scissor-wings, and flop-wings have been around for awhile in model rocketry. They are more commonly seen in International competition. At NARCON, Trip Barber showed a masterfully-engineered and exquisitely-built glider that folded down and fit inside a regulation Internats airframe. I had seen folded-wing designs before, but that one just blew me away.

Incidentally, the Estes Trans-Wing Super Glider was a folded-wing design. Venus Model Rocketry (http://www.venusrocketry.com/index.html) sells a couple of Mark Petrovich's scissor flop-wing designs: the Giblet B/G and the Gizzard R/G. His kits have absolutely fantastic quality for very affordable prices.

In Tim Van Milligan's Model Rocket Design and Construction there is a brief mention and a diagram of a "rotary flop wing" glider (designed by a Nevilles E. Walker) that strongly resembles an American Junior Classics folded wing glider (404 Interceptor?) It is shown in Figure 11-37 on page 97 of the second edition.

MarkII

blackshire
05-15-2009, 01:33 AM
Double-folded wing, folded scissor-wings, and flop-wings have been around for awhile in model rocketry. They are more commonly seen in International competition. At NARCON, Trip Barber showed a masterfully-engineered and exquisitely-built glider that folded down and fit inside a regulation Internats airframe. I had seen folded-wing designs before, but that one just blew me away.

Incidentally, the Estes Trans-Wing Super Glider was a folded-wing design. Venus Model Rocketry (http://www.venusrocketry.com/index.html) sells a couple of Mark Petrovich's scissor flop-wing designs: the Giblet B/G and the Gizzard R/G. His kits have absolutely fantastic quality for very affordable prices.

In Tim Van Milligan's Model Rocket Design and Construction there is a brief mention and a diagram of a "rotary flop wing" glider (designed by a Nevilles E. Walker) that strongly resembles an American Junior Classics folded wing glider (404 Interceptor?) It is shown in Figure 11-37 on page 97 of the second edition.

MarkII

Yes, that (N. E. Walker) is Jim Walker, as the former name also appears on his U-Control model airplane patent.

jflis
05-15-2009, 07:54 AM
A lot depends on the balsa these guys are made from - The cheap hand-launch gliders I've seen in the stores use such light balsa that they will shred on anything more powerful than a 1/4A (Ask me how I know! :rolleyes: ) You might trace out the parts on higher quality balsa and then build it.

Greg

Ah, yep. I would be familiar with the same pitfall... (http://jflis.com/hobbies/rocketry/photos/balsaglider01.jpg) LOL

Not pretty, but sure looked cool