AR-1 (oz6339)


AR-1 (oz6339) by Jack Caldwell 1982 - plan thumbnail

About this Plan

AR-1. Radio control slope soarer model.

Quote: "If you like speed, you've got to have a ship that will penetrate this is it! AR-1 by Jack Caldwell.

For years, the thrill of slope soaring has been an obsession with me. At first I haunted the nearby hills of Livermore, California, where I flew a variety of floaters. Sometime later, my brother in-law introduced me to coastal soaring at a site near Santa Cruz, California. We stood on a cliff overlooking a stretch of sea, whose beauty and sound were a treat in themselves. I'd never seen so many types of gliders in one place. I was surprised to see the speeds attained and the aerobatics performed. I could hardly wait to start building and flying the type of gliders needed to meet the challenge of the coastal conditions.

Recently, the spiraling cost of gasoline for the 150 mile round trip to Santa Cruz has forced me to do my flying closer to home again. My SR-7 and leadsleds won't fly well without that great coastal wind. I've had to find a plane with the same capability as the fast slope ships, that will fly in the lighter lift of the Livermore hills. It has taken some time and experimenting, but I've finally designed one that makes inland soaring as exciting as the coastal variety.

Some of the special feautures of the Ar-1 are: a sharp entry on the leading edge; landing flaps and a T-tail design. The Ar-1 flies inverted, has a respectable roll rate and does inside and outside loops close enough in size to make vertical Figure 8's a snap. It has a very gentle stall and the recovery is quite smooth.

If you like speed you've got to have a ship that will penetrate the wind. For a slope ship to do this, one must increase the wing loading. Want to go faster? Add more weight. But heavy airplanes don't fly in light air, so we trade weight for streamlining, hence the sharp leading edge. (Don't be tempted to deviate from the design if you want top performance.) The AR-1 is not recommended as a first airplane, but if you are tired of flying rudder-elevator, and have experience with quick response, high performance floaters, the AR-1 will be a nice change. When you can't fly with seagulls, the AR-1 will keep you up there with the buzzards.

The construction sequences may seem strange to you, but as you build, the reasons for my method will become clear.

Vertical Fin: Select the lightest material for the inner core parts. Cut core parts from soft 1/4 in balsa. Cut outer skins from medium-hard 1/16 balsa. The grain of the core pieces should be parallel to the tailpost. The grain of the outer skins will be parallel with the leading edge of the fin, Cut a piece of drive tubing 28in long. Cut a 1/8 x 1/16 shim to center the drive tube in its slot. Pin a skin over the plans, glue the front core piece in place and add the shim..."

Update 26/2/2023: Replaced the article file, full copy 10 pages in total, thanks to metalwizard.

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AR-1 (oz6339) by Jack Caldwell 1982 - model pic


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User comments

Site is awesome, big fan. The AR-1 should be identical to the Craft Air Freedom, I have one on order and will compare once I get the print.
Adventurerider - 11/03/2015
Photos of completed scratch build of AR-1 [more pics 003-009].
EricRMetzdorff - 03/11/2016
Here are some pics of my new AR-1, scratched from plans here printed at home and taped together [more pics 010-015]. Thank you for the plans.
John - 25/06/2018
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