The Piper Cheyenne is a medium-sized turboprop aircraft designed and developed by Piper Aircraft. Designed in the early 1970s, it was one of the most innovative designs of its time. This article explores some innovative aspects of the Cheyenne family of aircraft.
1
Wingtip fuel tanks
Total fuel capacity: 390 US gallons
- Fuel is carried in six tanks
- Three interconnected tanks in each
- A wing-wet nacelle tank
- Two bladder-type fuel cells
- Two optional wingtip tanks
The Piper Cheyenne was one of the first aircraft to design and use wingtip fuel tanks successfully. A unique feature seen in the early Cheyenne aircraft in the late 1960s, the 30-gallon wingtip fuel tanks provided additional range for the aircraft.
Remarkably, the wingtip fuel tanks were offered as an optional feature on the aircraft. However, almost all operators selected the option.
2
The flight stability augmentation system
For longitudinal stability
| Piper Cheyenne | III (PA-42) | IIIA (PA-42-720) | 400 (PA-42-1000) |
|---|---|---|---|
| Crew | 1-2 | ||
| Passengers | 6-9 | ||
| Length | 43ft 5in / 13.2m | ||
| Span | 47ft 8in / 14.5m | ||
| Height | 14ft 9in / 4.5m | 17ft 0in / 5.18m | |
| Wing area | 293sq ft / 27.2 m2 | ||
| Cabin W × H | 4ft 3in by 4ft 8in / 1.30m by 1.42m | ||
| MTOW | 11,080lb / 5,026kg | 11,200 lb (5,080 kg) | 12,050 lb (5,466 kg) |
| OEW | 6,389lb / 2,898kg | 6,837 lb (3,101 kg) | 7,565 lb (3,431 kg) |
| Fuel Capacity | 562 US gal (2,130 L) 3,752 lb (1,702 kg) |
582 US gal (2,200 L) 3,819 lb (1,732 kg) |
|
| 2× Turboprops | P&WC PT6A-41 | P&WC PT6A-61 | Garrett TPE331-14 |
| Unit power | 720 hp (537 kW) | 1,000 hp (746 kW) | |
Following the two Boeing 737 MAX crashes in October 2018 and March 2019, and the type’s reputation, the aviation world is aware of the Maneuvering Characteristics Augmentation System (MCAS). It may be surprising for some that the Piper Cheyenne featured a similar system, the flight stability augmentation system, in the 1970s.
The system was designed to control the longitudinal stability of the aircraft, which was affected by its powerful engines. Notably, the following variant, Cheyenne I, was released with less powerful engines to tackle the problem. Subsequently, the new variant was certified without the use of the flight stability augmentation system.
3
The most versatile load hauler
The Cheyenne IIXL
- Manufactured: 1981 – 1984
- Fuselage stretch: two feet
- Climb power limit: 500 shaft horsepower
- Seating: Eight
- Nose and aft baggage areas: 200 lbs each
- Cruise altitude: 29,000 ft
- Cruise speed: 250 knots
- Range: 1,170 NM
- Endurance: 4 hours 30 minutes
- Total number produced: 81
The Cheyenne IIXL was one of the most versatile load haulers among all the Cheyenne models. The type was designed to seat eight people, each with up to 170 lbs of load and full fuel. The fully loaded aircraft could efficiently takeoff and climb to an altitude of 29,000 ft and cruise at a speed of 250 knots.
With a full load of passengers, baggage, and fuel, the IIXL had an IFR range of 1,170 NM and an endurance of four hours and 30 minutes. Cheyenne’s innovative approach to components and systems led to the best variant for high payload operations.
The Cheyenne I was powered by two Pratt & Whitney PT6A-11 turboprop engines, each generating up to 500 shaft horsepower at takeoff. The reverse-flow free turbine arrangement engines had a maximum propeller speed of 2,200 RPM.
4
Corrosion-resistant structure
Highly-treated structural materials
| Piper Cheyenne | III (PA-42) | IIIA (PA-42-720) | 400 (PA-42-1000) |
|---|---|---|---|
| Cruise | 290 kn (537 km/h) | LR 282–305 kn (522–565 km/h) Max | LR 298–351 kn (552–650 km/h) Max |
| Range | 1,330 NM / 2,463 km | 2,270 NM (4,204 km) | 2,240 NM (4,148 km) |
| BFL | 3,920 ft (1,195 m) | 3,363 ft (1,025 m) | 3,180 ft (969 m) |
| Ceiling | 33,000 ft (10,100 m) | 35,000 ft (10,700 m) | 41,000 ft (12,500 m) |
| Climb rate | 2,380 ft/min / 12.1 m/s | 2,235 ft/min (11.35 m/s) | 3,242 ft/min (16.47 m/s) |
| Wing loading | 37.8 lb/sq ft (185 kg/m2) | 38.2 lb/sq ft (187 kg/m2) | 41.1 lb/sq ft (201 kg/m2) |
| Power/mass | 0.13 hp/lb (0.21 kW/kg) | 0.13 hp/lb (0.21 kW/kg) | 0.17 hp/lb (0.28 kW/kg) |
Over the course of the aircraft’s operational career, it had remarkably few major structural maintenance issues. With only a handful of airworthiness directives issued for the type, the Cheyenne family has mostly weathered well over the years. Piper has extensively used anti-corrosion materials for the structure, making it less prone to corrosion fatigue.
The use of anti-corrosion epoxy primers on structural materials resulted in a long-lasting airframe that required only minor maintenance. Moreover, Piper endured that parts for older aircraft types were not only in production but quite easily available for replacement. Piper takes pride in making the part upon request if one is not readily available.
According to the Aircraft Owners and Pilots Association (AOPA),
“For an aging airplane, the Cheyennes have remarkably few major maintenance problems or airworthiness directives. Structurally, they have weathered well over the years. Corrosion of the airframe has been rare, thanks to Piper’s use of extensive anti-corrosion treatments and epoxy primers. Parts availability for older Cheyennes hasn’t been a problem. Piper still stocks a lot of parts, but if a Cheyenne part is unavailable, Piper will still make you one.”