Plane & Pilot
Monday, December 5, 2011

The Littlest Boeing

Boeing’s venerable Stearman is one of the smallest landplanes the company built

Lloyd Stearman created the first Stearman in the early '30s and subsequently sold his company to Boeing. The then-Wichita-based company later won the contract to provide basic trainers to the Navy and Army Air Force, and the Stearman (sometimes branded by students as the "Yellow Peril") was the airplane of choice. The model 75 had spruce wings, tube-steel fuselage and fabric covering, and was considered dramatically overbuilt for its mission, so well constructed that back in the mid '30s, each airplane cost just over $11,000 to produce (in contrast to a Beech Staggerwing B17L that sold for $8,000). Translated to today's dollars, you could probably buy a decent used Lear 23 for equivalent money.

Stearmans were fitted with a bewildering variety of radial engines, everything from Continentals and Jacobs to Lycomings and Wrights, ranging in hp from 220 to 420. Mike Hanson's Stearman Kaydet features the original seven-cylinder Continental, rated for 220 hp.

After the war, the airplanes were pressed into civilian service and modified as necessary with such improvements as wheel pants, a cowling and speed fairings. These were employed as barnstormers, air show/wing walkers, mail planes and a hundred other jobs, some retrofitted with the huge Pratt & Whitney R-985 engine, boosting power to 450 hp. Hundreds of Stearmans were converted to crop dusters by simply mounting an aerial applicant tank up front and spray booms beneath the wings.

Hanson's airplane, like many of the early Stearmans, was equipped with a wood prop that provided limited performance. Hanson flew with the wood blades out front for the first thousand hours. "I call those the 'good-for-nothing' props, in between good climb and good cruise," says Hanson. He later retrofitted his airplane with the ground-adjustable all-metal McCauley prop, and picked up 10 knots cruise. (A Hamilton-Standard also is available.)

That's not to suggest cruise was a Stearman strong point, whatever the prop. With the drag of two open cockpits and accompanying wind shields, guy wires, struts, landing gear and two fat wings hanging in the wind, the Stearman has all the aerodynamic sophistication of a boxing glove. It's surprising that the stock Stearman managed the speed it did, about 90 knots. With 43-gallon tanks topped and a burn of 13 gph, the Kaydet has 2.5 hours endurance plus reserve at max cruise, enough for 230 nm range.

The airplane has a baggage compartment behind the aft pit, approved for up to 60 pounds. Typical useful load was about 750 pounds. Hanson's payload works out to a generous 492 pounds, two big folks and all the luggage you can stuff inside the baggage area.

With two wing walks, you can climb aboard from either side, but tradition suggests you treat the airplane like a thoroughbred—mount from the left. Step up on the wing, throw a leg over the sidewall, step down onto the seat and ease your rear end into the chute/cushion.

Labels: Piston Singles


Add Comment