James Kirby’s Skybolt is an aerobatic pilot’s Pot o’ Gold.
(From Kitplanes, 11/1995, Page 15)
By Howard Levy
James Kirby resides at Rainbow’s End: a private grass strip airport at Penns Grove, New Jersey, that is truly a homebuilders dream. There he found his own personal Pot o’ Gold — a Steen Skybolt that he built in his home workshop.
That wasn’t his first. Kirby has built three airplanes and assisted on another. The latter was a Stits Playboy he constructed with six other flying club members while serving as a Sikorsky H-19 Army helicopter crew chief in Germany during 1952 and 53. He returned to the United States before seeing it fly, and after completing military service, Kirby became a helicopter technical rep for Sikorsky Aircraft. His first true homebuilt was a Breezy that he built from plans obtained through designer Carl Unger.
The Breezies
Kirby went to work on his first Breezy in late 1969, and 18 months later he made its first flight. The airplane, designated Model JCK-1, had Piper PA-12 wings (Unger recommended Piper Cub or Aeronca Champ wings) and other PA-12 parts. It was powered by a 108-hp Lycoming 0-235 engine and was built at a total cost of $4500.
Kirby logged 460 hours on the airplane during the following 11 years and then sold it. “That was a bad idea,” Kirby said. “I really missed having it, so after a while, I dug out the plans and commenced work on another one,” he said.
Eighteen months later, his second Breezy — JCK-2 — took to the air, again with PA-12 wings, but with a 100-hp Continental 0-200 engine up front and a construction cost of nearly $10,000. “When building the first Breezy, I was able to obtain a good-condition Cub at a bargain price. With the second JCK-2, I had to purchase wing panels and other parts separately and rework them,” Kirby said.
Building a Skybolt
In 1985, another airplane was offered to Kirby — a Steen Skybolt biplane. Don Bennett, owner of Rainbow’s End and a Skybolt builder, had a second Skybolt project going. “It was a project that Don acquired but didn’t have a whole lot of time for. The fuselage was 60% welded and the wings had just been started, but since I was acquainted with Don’s air-plane and I knew what a fine aircraft the Skybolt is, I decided to take it on. Besides, I like projects.”
Kirby began work on the plane in March 1985, and worked on it evenings and weekends. The airplane was completed in May 1991. It was designated JCK-3 and its first flight lasted 30 minutes. “The only problem with the air-plane was a slight right rudder condition, which was corrected by adding a trim tab. Otherwise, the aircraft performed flawlessly,” Kirby said.
Skybolt Specs
JCK-3 is powered by a 180-hp Lycoming O-360-A3A engine and swings a 76×54 Sensenich metal propeller. The airplane’s construction is typical with fabric-covered wood wings and fabric-covered tubular steel fuselage and tail feathers. According to Steen’s plans, the top wing employs an NACA 632A015 airfoil and lower wing an NACA 0012. The upper wing is swept back 6 and has no dihedral, while the lower panels have no sweep but do have 2.3 of dihedral, and wing gap 47 inches at the lower wing roots.
Wing spars are solid spruce planks-the main spars in the top wing are located at 14% percent of the 42-inch wing chord, measure 5 inches high and 1-inch thick. Rear spars are at 57% chord, and are 4 inches high by 1 inch thick. Spar lengths are 12 feet. Lower wing panels have similar chords and spar positions, but the main spar is 4 inches high and 1 inch thick, and the aft spar is 3 inches high and 1 inch thick. Bottom wing spars are 9 feet 11 inches long.
All leading edges are made from 0.020 gauge 2024-T3 sheet aluminum that extends back to the main spars. Ailerons are Frise type and are installed on all four panels. Construction is similar to that of the wings except have leading and trailing edge spars.
All wood is glued with Chem-Tech T-88 epoxy. Wings are braced at the center section by tubular steel cabane struts, as well as outboard tubular steel I-struts. These have foam streamline fairings. Dual flying and landing wires are streamlined stainless steel.
The fuselage structure is of welded 0.25-inch-diameter 4130 tubes, with tubular longerons welded on and 0.25-inch by 0.8750-inch aluminum stringers. Both cockpits are 24 inches at the combing and 27 inches at the seats. The airplane is flown from the rear cockpit, and contains a Narco AT-I50 transponder and 810 corn and a II Morrow Apollo loran.
James Kirby built this Skybolt that incorporates a custom-designed smoke system.
The forward cockpit has dual controls, but the panel mounts only basic VFR flight instruments. Usable fuel is 28 gallons and is carried in an aluminum fuselage tank in the forward cockpit behind the instrument panel. An additional 8.5-gallon tank is installed in the upper wing center section.
Tail components have no airfoil. The tubular steel fin and stabilizer structure are braced with stainless steel wires. Elevator movement is by push-pull tubes and bell-cranks, as are the ailerons. The rudder has cables. The airplane is covered in Stits HS-90X with two coats of Aerothane clear and Daytona white, International Orange and Regal Red paint.
The Kirby-built Skybolt takes off with Ray Cella and Joe Flood aboard.
Cella, left, and Flood purchased the plane from Kirby, who wanted its aerobatic capabilities to be used.
The fixed maingear struts are built from 4130 tubular steel with aluminum fairings. Shock absorption is by bungee cords. Wheels have McCauley disc brakes with Cleveland master cylinders, and the tires are Goodyear 6.00×6. The wheelpants are fiberglass. A steerable 8-inch Scott tailwheel system is employed.
Beyond the Norm
It’s obvious from the fit and finish of the Kirby Skybolt that he likes to go a bit beyond the standard, so it’s no surprise that the plane incorporates a few changes not found in the plans.
The maingear has been moved 5 inches and made 2 inches longer to overcome the design’s tail heaviness. A Cessna-type worm drive is used in the horizontal tail surface trim system, and the cockpits contain an outstanding wood floorboard of marine teak veneer.
Kirby also designed the plane’s smoke system with the tank nicely concealed in the forward cockpit under the floor, and Kirby added cabin heat to both cockpits. The sliding blown canopy is a MacKenzie fabrication, as is the Firebolt-type nosebowl.
Nearly $40,000 was spent getting the plane into the air. The 25-hour restricted area flying was completed in 14 flights, and the airplane was signed off in December of 1991. However, it then sat on the ground through May 1993. It seems Kirby had more fun flying his Breezy.
The end result was that JCK-3 N36JK was purchased by Joseph Flood and Ray Cella of Lindenwold and Sicklerville, New Jersey, respectively. Why did he sell it? Kirby said, “The Skybolt is really an aerobatic airplane, and since I am not inclined to do much aerobatics, I wanted someone to have the airplane who would make use of its capabilities and appreciate what it can do.”
The New Owners
Flood, age 33, has owned 25 aircraft, most of which were taildraggers, and a mixed bag of older homebuilts and factory builts. Some of them he built; others he restored. His prior airplane was a Smith Miniplane project, obtained 40% complete, which he finished, flew for 100 hours, and then sold to purchase the Skybolt. Cella has a Hatz and a Pitts S-2E, both homebuilts, and is presently refurbishing an EAA Biplane.
Performance
Flood and Cella fly the Skybolt to its aerobatic potential. Loops, rolls, spins, inverted flight and snap rolls are standard weekend maneuvers. But why did they latch onto Kirby’s JCK-3? “I, in particular, wanted something faster than my Miniplane, as well as a two-seater with canopy and heat,” Flood remarked. “This airplane has all that, and besides, it’s one of the nicest Skybolts in the country.”
Flood reports that the Skybolt takes off in 400 feet at 65 mph. Climb rate is 1500 fpm at 80 mph, and cruise is 145 mph at 75% power at 2400 rpm with a resulting 8-gph fuel consumption. Approach and over-the-fence speeds are 80 mph, and touchdown is at 60 mph. The airplane has a 200-mph VNE speed, and stalls at 45-50 mph.
The front cockpit, rear cockpit and baggage area show Kirby’s attention to detail. Note the teakwood floor.
The Builder’s Future
Kirby plans to overhaul the engine in his 1946 North American Navion and give the airplane some TLC. “Then I’ll take a little time off before looking for another airplane,” Kirby said. “I always need a project to work on, you know.”
SKYBOLT PLANS are available from Steen Aero Lab for $165. Contact the company at 1451 Clearmont St. NE, Palm Bay FL 32905; call 321/725-4160. An info pack costs $10. [Address updated from original article – ed]