Bird of Time ARF

DYNAFLITE

Return of a classic sailplane

For many years one of Dynaflite's most popular kits, the Bird of Time (BoT) sailplane is now being offered by the company in an almost-ready-to-fly (ARF) version. The BoT's distinctive wing planform and legendary flight performance combine to make it a classic that's immediately identifiable. With minimal building time and inexpensive radio gear, you can enjoy the majestic beauty and magnificent flight characteristics of its 3-meter-span, thermal-soaring design.

The BoT design was created by Dave Thornburg for F3B multitask soaring competitions in the 1970s back when "iron men in wooden ships" reigned at such contests. With the availability of more modern materials and designs for full-on competition machines, the wooden-wing BoT is now more suited to lazy-day sport flying, and it's also perfectly at home in rudder-and-elevator-only contests. After three decades, it is still one great soaring machine.

KIT CONTENTS

The BoT ARF arrives almost entirely built. The kit includes an immaculately molded, shiny white fuselage with expertly filled seams and to which a decorative stripe has already been applied. The vertical stabilizer is part of the molding, so you don't have to mount and align a fin. The elevator-pushrod guide and an antenna tube are already installed, and the nose weight is in place.

Three built-up balsa wing sections come covered in Top Flite MonoKote film in an attractive color scheme, and a large decal of the "Bird of Time" logo is included. The complete hardware package provides the towhook, pushrods and all the necessary small fittings; a dark-tinted canopy and an extensive, 20-page instruction manual that contains eight drawings and 34 photographs round out the kit. The well-written manual presents substantial information on flight preparation and flight safety. For an advance peek at it, you may download a copy from Dynaflite.com/manuals/index.html.

Little else is needed to build the sailplane; only medium CA, epoxy, Goop glue, wing-joining tape, common hand tools and a 2-channel radio. The manual also lists 20 optional supplies and tools.

CONSTRUCTION

I completed construction of this prebuilt kit in just 7 ½ hours over the course of a week. The first order of business is to install the servos and elevator pushrod using Goop glue, which I find does a splendid job of joining wood, plastic, foam and fiberglass parts. The instructions call for a standard servo to be mounted in the tray for the elevator and a microservo with an extension cable in the tail for rudder, but I decided to build a new servo tray to accommodate two standard servos (see "Click Trip") to avoid having to use the long extension cable because it can cause the servo to jitter.

Epoxy the wing-joiner assemblies, and while they cure, install the elevator pushrod, if you have decided to put both servos up front. Holes for the second pushrod are provided in the pre-installed bulkheads, but you'll have to curve and firmly mount the rear end of the elevator pushrod. Some of the fuselage seam-joiner fiberglass tape was unattached on my fuse-lage, so I affixed it with epoxy and used a clothespin to hold it in place overnight.

Carefully fit the wing joiners; I had to grind mine a little. Then fit the rudder. The slots for the rudder hinges were out of alignment, but it was easy to cut new ones.

Now install the rudder control horn, and assemble the rudder and elevator control-cable fittings. On my BoT, the elevator control rod rubbed against the crescent-shaped cutout in the fin, but I easily corrected this with a Dremel Moto-Tool (you could also use sandpaper). Epoxy in the wing-incidence pins and the wing's leading-edge mounting pegs.

Fit the rear-wing hold-down plate and apply epoxy to another area on the loose seam tape. Install the adjustable towhook mount with Goop, and allow the adhesives to cure overnight.

Assemble the sailplane, and then check its center of gravity (CG), lateral balance and wingtip washout. To balance at the recommended point, mine needed 3A ounce of additional nose weight, no wingtip weight and no washout adjustment. Cut a piece of foam for the receiver mount, which also holds the battery pack in place.

FLIGHT PREPARATION

The instruction manual covers in detail how to confirm and adjust the fore-and-aft CG balance, the wings' lateral balance and the control-surface throws; all are important to the way the plane flies. It's also important to check wing washout. You want the wings to have a slight twist so that the tips' leading edges are down and their trailing edges are up when compared with the center of the wing. This is so that the wing center stalls before the tips and causes the stalled airplane to fall straight forward (easier to control) rather than to tip-stall first (more difficult to control).

The tips' distinctive shape makes it impossible to check for washout in the traditional way (holding the wing halves flat on the workbench). I used an incidence gauge to check my wing washout and found it to be slight-about 0.5 degree at the longest-chord portion of the tips (mine flew fine).