Baby Bowlus (oz15975)

About this Plan

Baby Bowlus. Radio control sport-scale model glider. All-sheet balsa model. Wing uses Jedelsky style construction.

Direct submission to Outerzone.

Update 17/4/2025: Added kit review from Model Builder Aug 1973, thanks to theshadow.

Quote: "Products In Use: Southwestern Sailplanes' Baby Bowlus. By Bill Northrop.

Quick and dirty doesn't exactly sound like the kindest combination of adjectives to use in describing an R/C sailplane kit. However, this particular expression is quite familiar to most modelers, and they realize what it means - a kit that goes together fast, and even though the designer has cheated by cutting unnecessary corners and achieving results in a functional way only, the resulting model does its thing up in the air and that's what counts the most anyway.

Southwestern Sailplane's Baby Bowlus would create howls of laughter from static scale judges and those who go for streamlined this and filleted that's, but when you suddenly find yourself fresh out of R/C gliders, it's the quick and dirty way to get back in the air by next weekend - and the cost is only $19.95.

The SS Baby Bowlus is a stand-way-off-scale model of a famous glider which dates back to the 1930's. The designer Dave Thornburg employs sheet balsa construction throughout in creating this 72 inch model. Tail surfaces are machine-cut to shape from sheet stock and only require light trimming and sanding. Fuselage sides are also machine cut, as is the noseblock profile.

Fuselage construction consists merely of glueing triangle stock in place, joining the sides with the noseblock in between, and then planking away until it's all boxed in.

The wing consists of two panels, joined at the center in hand-launch glider fashion, with the joint reinforced by applying a layer of celastic (supplied) top and bottom. Each panel, as fur-nished in the kit, is made up of two sheets of balsa, joined Jedelsky style but without ribs, and the tips cut to an elliptical (scale outline). We felt it appropriate, and in keeping with the fast-completion image of the kit, to merely finish the glider in natural grain. Three coats of sanding sealer were applied, smoothed after each coat with the same piece of 400 wet-or-dry (by the last coat, the back of the paper is as smooth as the working side). Finally, we paste-waxed the whole thing,

For a radio, we literally 'stuck' in an RS system. One of the many plus points about R/C soaring is the fact that the radio equipment manufacturers don't get up tight if you install their servos with double-stick foam tape - in fact, not even if you use double stick carpet tape (no foam)! To complete the installation, the receiver and battery pack were wrapped in foam (yep, scraps of under-padding rescued from the new living room carpet installation!), and stuffed into the nose. We didn't use the airborne switch - it's just too easy to reach in the open cockpit and shove the connectors together.

The RS radio has several interesting features, and 'small' is one of them. The receiver is the smallest multi-channel digital proportional unit on the market (see this month's ad). To really appreciate it, you had to be fooling around with R/C 10 to 15 years ago. You could put half a dozen RS receivers inside of one Bramco 8-channel (that corresponds to 4 control functions as we know them now) case and they'd still rattle around!

Came the time to test glide the assemblage. Since it was about 2 AM and we still carry traces of being a typical modeler, off we went to the front yard. The lack of angular difference between the wing and stab had us worried, but trusting Dave implicitly, we lined up a glide path between the lawn sprinkler pipes, twitched the controls, and heaved. The nose of the Bowlus almost removed our big toe. Back at the workbench, we quickly eyeball-cut a V-shaped shim which put about a 1/4 inch of incidence in the wing. It's now a permanent installation. Also, we glued back on a piece of the rudder which was broken off as it dragged through the grass. The bottom rudder was then trimmed short so that it was protected by the forward bottom fin.

The next glide (at 2:35 AM) was fine - right between the sprinklers, thanks to R/C.

Several days later we had a chance to really fly the Bowlus from the nearby slope in Laguna Niguel. With a final apprehensive glance at the near-flat, V dihedral (After all, we couldn't trust Dave any more following that incidence business!) we threw the Baby Bowlus into its maiden flight. The ship flew quite well, working its way back and forth on the slope until it was pretty well overhead. One thing was obvious though; for the less experienced modeler, and for more relaxed flying by the old hand, something had to be done about the constant threat of tip stalls.

Our first thought was to chop the wings off about 12 to 15 inches from the tip and put in polyhedral - but this didn't seem like the right way to treat even a Stand-Way-Off Scale glider, so instead we decided on washout, a pretty standard precaution among R/C sailplaners.

After several futile attempts to steam washout into the fairly thick sheet wings, we finally opted to cut 'ailerons' out of the tips and glue them each with about 3/16 inch of permanent 'up'. The operation is performed by using all of a 12 inch metal ruler, juggling its position until a straight cut can be made, from the bottom, almost through to the top. Next, crack the ailerons upward and then pin them in position, using a straight edge to check equality. A bead of glue is then simply run into the open slot. Voila! Washout!

The Baby Bowlus is a pleasant change from the usual sleek canopied glider and always brings lots of attention. It can be put together quickly, and with moderate care, will perform nicely (with the recommended modifications).

RS Systems, distant relative of the famous Bonner radios of the 1960's, has been hanging in there for quite a few years, always on the fringes of notoriety. It has been quietly and continuously improving, becoming noted for its reliability and for its prompt factory service. We expect to see it established as one of the few major R/C equipment manufacturers within the next year."

Update 20/4/2025: Added kit review from RCM, May 1973, thanks to RFJ.

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