Boeing L-15 Scout
|YL-15 (foreground) of US Fish & Wildlife Service|
|First flight||13 July 1947|
The Boeing L-15 Scout or YL-15 was a small, piston engine liaison aircraft built by Boeing in very small numbers after World War II. It was a short take-off and landing (STOL) aircraft powered by a 125 hp Lycoming engine. The L-15 was an attempt by Boeing to expand its product line as World War II drew to a close and Boeing's production of combat aircraft declined. Boeing decided against marketing the L-15 as a general aviation aircraft, and the twelve that were produced went to the United States Army for testing then were transferred to the U.S. Fish and Wildlife Service in Alaska for various duties.
The scout was a conventional geared aircraft that was also tested on ski and float gear. The unique fuselage tapered sharply behind the pilot similar to a helicopter fuselage, with a high-mounted boom supporting the tail surfaces. The original design included a single vertical stabilizer, but two small downward-mounted stabilizers were used on production models. Spoiler-ailerons were used for roll control, and full length flaps were mounted on the trailing edge of the wings. The rear fuselage was all-window, and the tandem co-pilot could swivel the chair rearward.
Although its cruise speed was only 101 mph, the aircraft was rated to be towed by another aircraft at speeds up to 160 mph.
One airworthy example still exists, owned by the same family for over 63 years (YL-15 EAA video)
Data from Boeing Aircraft since 1916 
- Crew: Two (pilot and observer)
- Length: 25 ft 3 in (7.70 m)
- Wingspan: 40 ft 0 in (12.20 m)
- Height: 8 ft 8½ in (2.65 m)
- Wing area: 269 ft² (25.0 m²)
- Empty weight: 1,509 lb (686 kg)
- Loaded weight: 2,050 lb (932 kg)
- Powerplant: 1 × Lycoming O-290-7 four cylinder air cooled horizontally opposed engine, 125 hp (93 kW)
- Maximum speed: 97 knots (112 mph, 180 km/h)
- Cruise speed: 88 knots (101 mph, 163 km/h)
- Stall speed: 30 knots (35mph, 56 km/h)
- Service ceiling: 16,400 ft (5,000 m)
- Rate of climb: 628 ft/min (3.2 m/s)
- Wing loading: 7.62 lb/ft² (37.3 kg/m²)
- Power/mass: 0.061 hp/lb (0.10 kW/kg)
- Endurance: 2¼ hours normal, 5½ hours with external fuel
- Plane and Pilot. July 1967. Missing or empty
- Bowers 1989, p.374-375.
- "Grasshopper's Eyes Widen" , March 1947, Popular Science article with explanation of unique features of L-15A
- "Eye For Ground Forces Fly As Low As 50 mph" , March 1947, Popular Mechanics good photo of rear observer's unique position
- "XL-15 Folds Up For A Tow" , February 1948, Popular Science middle of page
- Flight, November 20th 1947, page 573 bottom of page shows XL-15A on floats, with specification when operated as float plane
- "New Eyes For The Army Ground Forces" , October 1947, Popular Science US Army recruiting ad featuring L-15A
- "EAA video: Boeing YL-15 - Defying Physics" , EAA YouTube Published Oct 20, 2017