Sunday Glider (oz15586)

About this Plan

Sunday Glider. Radio control glider model. Uses the Ace 'Sunday Wings' foam wing.

Quote: "Sunday Glider. Designed and drawn by Ken Willard. Traced and inked by Roger Greene. Sport glider for Ace 'Sunday Wings'. Suitable for thermal training and for slope soaring in winds up to 30 mph."

Note plan also shows optional installation of Cox .020 Tee Dee in the nose.

Direct submission to Outerzone.

Cleanup by theshadow.

Note this plan used the Ace Foam wing. For a plan showing how to construct a replacement wing in balsa (both tapered and straight-chord) see Ace Foam Wing (oz8557) thanks to AndyKunz.

Update 27/5/2026: Added article, thanks to dfritzke.

Quote: "Some time ago I designed a little six-foot glider for general sport use. It was easy to build and repair, and had a reasonably good glide which would let it catch moderate thermals. But on the slope it wouldn't penetrate too well. The maneuverability though, was great, and I used it to make all my spot landings for LSF Levels I and II. Then I hung it up in the workshop and went on to other projects.

Recently, with the increasing interest, both thermal and slope, for gliders I had an idea how to make the little sport glider an all-purpose model for Sunday flying. Thus was born the Sunday Glider. The idea was very simple; I'd take four Ace foam wings, like the Ace High, and fit them on the Sunday Glider fuselage.

However, there was one change; instead of using the tapered panels outboard, four straight panels would he used, with the intent of reducing any tip stall tendency to the absolute minimum (tapered wings without washout will almost invariably have a bad tip-stall characteristic).

Flights with the prototype were almost unbelievably successful. The first
flights were made with a Cox QZ 049 in the nose. It was too much power, so I replaced it with an 020 - the Tee Dee, not the Pee Wee - and that gave just about the right amount of power for a slow climb to around 400 feet. Several times, when the 020 quit I continued to thermal soar for five to ten minutes, with a couple of flights over 20 minutes. Not bad for a job that was really intended more for penetrating on the slope.

Next, I tried towing it up with my hi-start, which is a light. one. It went up fine, but occasionally I did notice a ten-dency to veer off. Tom Christian, a modeling, friend, had built one and his did the same thing, only worse, That worried me. It seemed that the bending load on the center panels was more than they were designed for, so there had to lie a reinforcing 'fix.' And it came very easy. Using a razor, I cut a triangular slot in the top of the center panels and inserted a piece of 3/8 triangular balsa stock, using Titebond to secure it, and making sure that the top of the balsa was flush with the foam.

That was all it needed. With the added strength in the center panels, hi-starts went straight up without veering, and then I put the QZ back in, with the prop on forward, and sent the model up to do some loops, rolls and pullouts to check the strength. No problems. And again, some thermal flights of over five minutes. Admittedly, it takes a bit of skill to make it thermal, but because of its maneuverability it can turn inside a 20-foot updraft once you learn how.

On the slopes you wouldn't believe it. We had a slope race recently, and when the wind was light and the unlimited class racers wouldn't stay up, the Sunday Gliders were racing very well. Then later on, the wind picked up to around 30 mph and the Sunday Gliders were still penetrating without any difficulty.

It's a fun machine - one you can build in a few hours and repair in a few minutes with five-minute epoxy.

Wing: It's made from four Ace foam wings. To make it even easier, Paul Runge of Ace will be packaging the wings with the proper amount of dihedral already cult in the wing tips. This will save you about an hour and a half of cutting, sanding and fitting to get the 3-1/2° accurately shaped before joining the wings. All you need to do is coat the tips with five-minute epoxy and butt-join the panels..."

Supplementary file notes

Article.

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