EAA Sport Aviation - January 2010

Jack was able to purchase. Phil Riter of Defiance, Ohio, built the new mast and fabricated new sheet metal for the cockpit and engine cowlings. ;e four rotor blades were a bit mangled, but the spars were usable; however, the rotor ribs and everything else was made new.

The more conventional parts of the structure presented the usual restoration challenges, but most of the fuselage and tail surfaces are original, while the wings are mostly new. ;e engine was missing, and with Kinner R-5s practically unobtainable, a later Kinner R- 55 model was obtained and sent to Al and Brad Ball in Santa Paula, California, for overhaul.

Kinner experts advised that it was a bad idea to use a metal prop on a Kinner because of the harmonics, but the type certificate data sheet for the PA- 18 says “metal propeller,” so a field approval was needed for this and for the different dash number engine. This was a struggle, but with the help of Scott Fohrman of the FAA’s Chicago Aircraft Certification Office, all was sorted out, and by June 2008, Jack had a new airworthiness certificate. With the original N number now reassigned, he had to settle for NC1267B.

FLYING THE AUTOGIRO/ A typical flight in the Pitcairn
PA- 18 starts with a thorough preflight inspection, paying
special attention to the rotor head. I’ve never heard of any
major problems with Pitcairn rotor heads, but I don’t want

to be the first to learn of them. Like many antique aircraft, the PA- 18 is flown from the back seat; the cockpit is roomy enough, and all of the controls fall to hand easily. ;e instrument panel is typically sparse for the era, and aside from the usual gauges it contains a rotor tachometer. ;e compass is mounted below the panel on the back of the front seat, and we’ve hidden a modern electronic rotor tach just above it since the 1932 one gives inaccurate readings, which can be critical.

On the left sidewall of the cockpit, in
addition to the throttle, are two handles
jutting out horizontally that move fore

;e Kinner engine has good impulse magnetos, so it usually starts easily, with its characteristic clatter. ;e original aircraft had a Heywood compressed air starter, but we don’t have this and have to hand prop. Taxiing has to be done carefully because the tail wheel is non-steering and full swiveling, and the aircraft is short coupled, which can make it more susceptible to ground looping, although the old cable-operated mechanical brakes work well enough.

Once the ’giro is at the takeo; posi-
tion, the parking brake is set, and cockpit
checks are done, the throttle is set to 800
“Autogiros have always been somewhat of a Holy
Grail for antique airplane enthusiasts, mysterious
and (almost) lost to history.”

and aft in quadrants. ;ey will be unfamiliar to fixed-wing pilots and are labeled “Rotor Starter” for the aft one and “Rotor Brake” for the forward one. ;ey’re inter-connected, so you can’t put one on while the other is on. ;e brake actuates an automobile-type drum brake in the rotor head to help slow down the rotor after landing, and the rotor starter engages a clutch on the back of the engine to spin up the blades before takeo;.

rpm and the rotor starter lever is slowly moved forward to engage the clutch. ;is turns the drive shaft to the rotor and starts the big blades turning. Because the blades have lead-and-lag hinges as well as flapping hinges, the center of gravity of the rotor is o; center to start. From about 20 rpm to 60 rpm there is a ground resonance that shakes the whole machine. It smooths out as the rpm goes over 60, and when the rotor tach shows a steady 67 or

THE GENIUS OF JUAN DE LA CIERVA’S AUTOGIRO

Having each blade hinged at the root allows the rotor system to equalize lift around the entire rotor disk. The hinges allow the advancing blade to rise while the retreating blade descends.