Piper PA-30 Twin Comanche
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| PA-30 Twin Comanche | |
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| Type | Cabin monoplane |
| Manufacturer | Piper Aircraft |
| Maiden flight | 1963 |
| Number built | 2,142 |
The Piper PA-30 Twin Comanche is a American twin-engined cabin monoplane designed and built by Piper Aircraft. It was twin-engine development of the PA-24 Comanche single-engine aircraft. A variant with counter-rotating propellers was designated the Piper PA-39 Twin Comanche C/R.
[edit] Development
The Twin Comanche was designed to replace the Piper Apache in the company's line up of products. The Twin Comanche was developed from the single engined Comanche by Ed Swearingen who at the time operated a facility that specialized in the modification of production aircraft. The normally aspirated aircraft was equipped with two 4-cylinder 160 hp (120 kW) Lycoming IO 360 -B1A fuel injected engines, but 180 hp (135 kW) and 200 hp (150 kW) engines were available as a Miller modification. A version with turbocharged engines for higher altitude flight was also developed, using IO-C1A engines of the same nominal power. All Twin Comanche engines enjoyed long TBO's (2000 hours for the B1A) and developed a reputation for reliability. The PA-39 was a version with counter-rotating engines (to eliminate the critical engine) that replaced the PA-30 in the early 1970s. The Twin Comanche was produced on the same Loch Haven, Pa., production line as its single-engine cousin; production ceased when the factory was flooded in 1972. Piper chose at that time to focus on its equally-popular Cherokee 140/180/235/Arrow line, manufactured in Florida, and its highly popular twin-engine Seneca, which is essentially a Twin Cherokee Six. The Piper PA-40 Arapaho had been scheduled to replace the PA-39 in the 1973-4 timeframe. Three were manufactured, and the aircraft was already fully certified when the decision was made not to proceed with the manufacture. One of the three Arapahos was destroyed in a flat spin accident in 1973; the test pilot (who was none other than future aviation entrepreneur Clay Lacy) successfully escaped. One was scrapped by Piper. One remains flightworthy as of this writing but is not currently being flown.
[edit] Design
The Twin Comanche is a low-wing cantilever monoplane with a retractable tricycle landing gear. The Twin Comanche is the most fuel efficient aircraft in its class. With tip tanks, the aircraft holds 120 gallons (454 l) of fuel. Fuel burn at typical cruise settings is approximately 15.5 gph (58.7 lph) with a cruise speed of 165 kts. It easily climbs to 18,000' (5,500 m) when desired (24,000' - 7,300 m - if turbocharged). When compared with the Seminole (in reality a Twin Arrow), the Twin Comanche goes faster, carries more, burns less fuel, climbs more rapidly and ultimately higher, is quieter, and is more difficult for a novice to land. When compared to the Seneca, which is really quite a different aircraft, the more noticeable differences are in handling. Other contemporary competitors to the Twin Comanche were the Raytheon (Beech) Travelair, and the Grumman Cougar.
[edit] Operational history
An early high-ratio of training accidents on the original Twin Comanche was reduced by raising the minimum airspeed at which engine-out flights were conducted. In the 1960s, engine-out stalls were performed as part of multiengine training at low altitudes. This, combined with the Twin Comanche's ease of entry into a flat spin if an engine-out stall is taken too far, led to many early accidents. A revision of training procedures combined with revised placarded speed restrictions for single engine operation as well as a service bulletin which added a rudder-aileron interconnect and leading edge stall strips resulted in significant improvement in the accident rate.
[edit] Variants
Three versions of the PA30 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 in 1965. These used Rajay turbochargers with manual wastegates operated by twin knobs under the throttle quadrant. They were properly termed "turbonormalized" since the compression ratio and maximum manifold pressure remained unchanged. Pilots were required to use care to avoid overboosting at low altitudes, since no overboost popoff valves were used. Since there was 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 Comanche
- PA-24 with engine removed and nose faired in and powered by two Lycoming IO-320-B1A engines in wing mounted nacelles. Options included turbochargers, deice boots, tip tanks (for 120 gal total).
- PA-30 Twin Comanche B
- As PA-30 with a third cabin window each side and an option fifth or sixth seat. Optional turbocharged version with Lycoming IO-320 engines.
- PA-30 Twin Comanche C
- As Twin Comanche B but with new instrument panel and other minor variations. Optional turbocharged version.
- PA-30-200 Twin Comanche B
- Experimental PA-30 with two 200hp Lycoming engines, one only.
- PA-39 Twin Comanche C/R
- PA-30 with counter-rotating 160hp Lycoming IO-320-B1A engines and modified wing leading edges. Optional turbocharged version with two IO-320-C1A engines.
- PA-40 Arapaho
- Developed and fully certified version of PA-39 with enlarged six-seat fuselage and modified landing gear and larger windows. Three prototypes only.
[edit] Specifications (PA-39)
Data from The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 2735
General characteristics
- Capacity: four/six seat
- Length: 25 ft 2 in (7.67 m)
- Wingspan: 36 ft 9½ in (11.21 m)
- Height: 8 ft 3 in (2.51 m)
- Wing area: 178 ft² (16.54 m²)
- Empty weight: 2270 lb (1030 kg)
- Gross weight: 3725 lb (1690 kg) each
Performance
- Maximum speed: 205 mph (330 km/h)
- Range: 1200 miles (1931 km)
- Service ceiling: 20,000 ft (6095 m)
Related development
[edit] Reference
- The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing
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