thumb|right|Turbo PA-30 with tip tanks and vortex generators installed
thumb|right|PA-30 Twin Comanche with modified dorsal fin and modified air intake in nacelles
thumb|PA-30 Twin Comanche
The Piper PA-30 Twin Comanche is an American twin-engined cabin monoplane designed and built by Piper Aircraft. It was a twin-engined development of the PA-24 Comanche single-engined aircraft. A variant with counter-rotating propellers was designated the Piper PA-39 Twin Comanche C/R.
Development
The Piper PA-30 Twin Comanche was designed as a twin-engined variant of the Piper PA-24 Comanche. A complex light twin, with retractable landing gear, seating 4 (in original models) to 6 (in later models), and cruise speeds ranging from 160–210 mph on twin 160 horsepower engines, it competed with the more-powerful Cessna 310 and Beech Baron, and later with Piper's other light twins. The design was designated the PA-30 on March 17, 1962 and named the Twin Comanche. For marketing reasons, the type was re-designated the PA-39 and received FAA Type Approval on November 28, 1969. The first production aircraft was completed on December 23, 1969. Collins pointed out in another article that year that one FBO had suffered four fatal V<sub>MC</sub> roll-over spins. Two were in a Twin Comanche, One in a Beech Travel Air and one in a Beech Baron. It is not surprising that the Twin Comanche had a higher number of such crashes as it was used more often as a training aircraft. The FAA performed a series of flight tests on the Twin Comanche and NASA conducted wind tunnel tests and found no unusual tendency to spin beyond what would normally be expected given the airflow of the normally rotating propellers.
In the 1970s, the FAA changed its training standards and required flight instructors to obtain a separate rating to teach in multiengine aircraft. The V<sub>MC</sub> crashes dissipated dramatically. In 1997, the Aircraft Owners and Pilots Association (AOPA) Air Safety Institute published a safety review of the Comanche series aircraft and concluded that the Twin Comanche showed no greater tendency for V<sub>MC</sub> roll-over spins than comparable aircraft. Kristin Winter, a long time Twin Comanche instructor, operator, and trained accident investigator, reviewed the NTSB records for a ten-year period ending in 2014 and concluded that the Air Safety Institute's report was correct in its conclusions. Of the six single engine loss of control crashes, most resulted from inexperienced pilots and substandard training.
Prince William of Gloucester bought a Twin Comanche and used it as his personal aircraft for several years in the 1960s. He flew it from the United Kingdom to Nigeria, where he held a diplomatic post; then later returned in it to the United Kingdom and flew it to Japan when he took up a diplomatic post in that country.
A Twin Comanche was flown in the 1992 and 1994 French Arc en Ciel air races. It is the only US aircraft to have raced twice around the world. In the pilot-skilled races, 1992 pilot and Pioneer Hall of Fame enshrinee and 100 Aviation Hero for the First Century of Flight, Marion P. Jayne and her daughter Nancy Palozola placed second. In 1994 Jayne and her daughter, Patricia Jayne (Pat) Keefer won the FAI Gold Medal in what, so far, is the longest race in history at over 21,000 miles flown May 1–24, 1994. With FAA approval the twin carried a total of 252 gallons in 11 tanks and at maximum power went over 2,100 miles nonstop between Marrakech, Morocco and Istanbul, Turkey in 11:19 hours.
All Twin Comanche engines have long times between overhaul (2000 hours for the B1A, 1800 for the IO-320-C1A) and have developed a reputation for reliability.
Following a string of crashes involving pilot loss-of-control in single-engine flight (due to engine failure, or in pilot training for engine-failure conditions), Piper sought to alter the plane's single-engine behavior at low airspeeds (such as takeoff and landing). The resulting PA-39 Twin Comanche C/R was a modified version with counter-rotating engines (to eliminate the "critical engine" which, when failed, created the greatest risk of loss-of-control). The PA-39 replaced the PA-30 in the early 1970s. At least one comparative study of U.S. crash rates for the PA-30 and PA-39 indicated that crash rates for the counter-rotating PA-39 were only one-third of those for the conventional PA-30. Piper subsequently expanded the counter-rotating engine development to its other light twins.
Piper PA-30 Twin Comanche has had multiple safety incidents, including fatal accidents also in the 21st century. As of November 3, 2019, 80 PA-39's remain on the Federal Aviation Administration (FAA) registry.
Variants
Three versions of the PA-30 were produced: the original, a B model, and a C model. The B and C models can carry six passengers and can be identified by the additional side windows. Factory turbocharged engines became available with the B model. Turbo models can be identified by the presence of vents on the nacelle sides. These use Rajay turbochargers with manual wastegates operated by twin knobs under the throttle quadrant. They are properly termed "turbonormalized" since the compression ratio and maximum manifold pressure remained unchanged. Pilots are required to use care to avoid overboosting at low altitudes, since no overboost popoff valves are used. Since there is no accompanying power increase, the B/C models simply give owners a fuel vs. passenger tradeoff. The two rearmost seats, occupying the baggage compartment, are quite small.
;PA-30 Twin Comanche
:Four-seat twin-engined cabin aircraft powered by two 160 hp (119 kW) Lycoming IO-320-B1A engines in wing-mounted nacelles. The aircraft was available in five levels of equipment fit:
::Standard.
::Custom – additional instruments
::Executive – additional instruments and radio equipment
::Sportsman – Palm Beach interior and exterior and AltiMaticII autopilot
::Professional – full IFR panel
;PA-30 Twin Comanche B
:PA-30 with a third cabin window on each side and an optional fifth or sixth seat
;PA-30 Turbo Twin Comanche
:Turbonormalized version of the PA-30B Twin Comanche, powered by two Rajay turbonormalized IO-320-C1A piston engines
;PA-30 Twin Comanche C
:Twin Comanche B with new instrument panel, switches, and other minor variations. Optional turbonormalized version.
;PA-30-200
:Experimental variant with two 200 hp Lycoming engines, one built
;PA-30-290
:Experimental variant with two 290 hp Lycoming IO-540-G engines, one converted from PA-30 prototype
;PA-30 Twin Comanche D
:Original designation for the PA-39.
;PA-39 Twin Comanche C/R
:PA-30 with counter-rotating 160 hp Lycoming IO-320-B1A engines and modified wing leading edges
;PA-39 Turbo Twin Comanche C/R
:Turbocharged version of the PA-39 Twin Comanche C/R
;Piper PA-40 Arapaho
:Developed and fully certified version of PA-39 with entirely different wing and extensive fuselage modifications. Three prototypes only.
Specifications (PA-39)
frameless|right|3-view line drawing of the Piper PA-30 Twin Comanche B
See also
References
;Notes
;Bibliography
- The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985), 1985, Orbis Publishing
External links
- Piper Twin Comanche C/R – Flying