Ryan ST (oz13135)

About this Plan

Ryan ST. Free flight profile scale model. All-sheet design.

Quote: "An excellent project for our Sunday free fighters. Build this semi-scale quarter A version of famous old trainer for the max in flight performance for a minimum of effort. Ryan ST, by Dave Thornburg.

On a calm and unusually warm Sunday in March, I took the little Ryan out to the local flying field for the first time. After a single hand glide (trim your planes at home the day before, and you get a terrific reputation for models that fly right off the board) I turned her loose with 1/2 cc of fuel and a very rich engine. It was a free flighter's dreams: slow left climb, good transition, gentle glide to the right, one-piece landing.

I resumed breathing and retrieved the ship with affected carelessness, slyly watching a group of nearby modelers. Sure enough, one fellow broke from the group and came puffing over excitedly. A Ryan ST! he exclaimed. Scratch built?

Yes, I proclaimed modestly. He asked to borrow the plans and I assented happily, launching into a carefully planned extemporaneous oration about how easy and inexpensive the Ryan is to build. But he was lost in thought. Do you think I should go to an .049? he asked finally. Oh, no, I assured him, The .02 is more than enough power. The plane only weighs five ounces

I'd better use an .049, he decided. Mine will be heavier, what with the bellerank and leadout wires and push-rod.

Actually, the Ryan is a natural for control line flying: its low wing and profile fuselage give it the appearance of a ukie trainer. But acute muscular dis-coordination made me a diehard free flighter years ago - so you needn't ex-pect any construction tips from me!

CONSTRUCTION: Start construction of your free flight Ryan by choosing the balsa with care. For all of the flying surfaces, medium to light C-grain balsa is a must. Sig stamps their C-grain for easy identification, and publishes in the model magazines from time to time a 'Balsa ID Chart.' A really on-the-ball hobby dealer will have one of these charts handy, and will be glad to help you select your wood. The fuselage stock is less critical: a good straight piece of medium density wood will do nicely. One piece of 1/4 x 3 x 36 in will build the fuselage, engine cowl cheeks and wheel pant cores.

The first step is to cut out all of the major pieces from the appropriate wood sizes. Contact cement really speeds this kind of construction, although white glue or regular model cement will work fine. Whatever glue you use, take care to avoid applying too much, especially when making the butt-joints on the flying surfaces. The excess glue that squeezes out of a crack is hard to sand off later, and makes a good covering job dificult.

WING On a flat surface such as a drawing board or table, join the leading edges to the trailing edges, and sand the joint smooth when dry. (A piece of wax paper from the kitchen will keep the wings from sticking to the board.) You might round the leading edges just slightly for streamlining, but it's just as well to leave the trailing edges square: it makes them easier to cover neatly and more warp-resistant than a feathered trailing edge. Now add the four outer ribs to each panel, omitting the root ribs until the panels are joined at the dihedral break. The Ryan needs 3-1/2 in of dihedral in each panel for stability; this means you must block up one tip 7 in when gluing the dihedral joint (see photo.)

When the dihedral joint is thoroughly dry, add the root ribs and dihedral joint reenforcing. Light Celastic is ideal for this purpose, although gauze, silk or any other lightweight material will do. If you make the reenforcing strip about the size of the plywood wing mount, it won't show when the wing is in place.

FUSELAGE: The fuselage is a pushover. Just remember that the two inner cowl blocks must be 3/4 in thick. (If you haven't any scrap 3/4 sheet on hand, laminate them from thinner wood. Note that their grain should run vertically, while the cheek blocks need a horizontal grain for strength.) Cement these two pieces firmly in place, and sand the proper bevel in the front of them to accommodate the firewall at the angle shown on plans. Cut the firewall from 1/16 plywood, bore engine mounting holes, and cement in place. Add the cheek blocks and, when the glue is dry, carve and sand the entire nose to the shape shown on plans..."

Direct submission to Outerzone.

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