The Smith X-99 Prop-Jet was a six-seat turboprop powered business aircraft designed in the United States in the 1980s. Only one was built.

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Design and development

The Prop-Jet was an attempt to produce a small, propeller driven business aircraft capable of cruising at speeds above 350 mph (560 km/h). It was powered by a 550 shp (410 kW) Pratt & Whitney Canada PT6 turboprop engine, mounted in a long nose and driving a four blade, constant speed propeller. The fuselage was a monocoque constructed from graphite and glass-fibre epoxy sandwich. The pressurised cabin accommodated pilot and five passengers in three rows of seats, with a baggage space behind. Access was by port side doors forward and another over the trailing edge on the other side. The tail unit was made from Kevlar/graphite/glass fibre epoxy sandwich. The fin was swept and the tailplane mounted, with anhedral, almost at the top of it. The elevator carried an electrically driven trim tab.[1]

To speed the completion of the first prototype, the Prop-Jet used the wing and undercarriage of a Beechcraft Baron 58P, though a composite structure wing was envisaged for production aircraft. The Beech wing was a two spar aluminium box structure, without sweep and mounted between mid and low positions with dihedral of 6° and fitted with slotted Fowler flaps. The tricycle undercarriage was enclosed behind doors after retraction.[1]

The Prop-Jet flew for the first time on 29 July 1982. By 1985 Mike Smith was reported as seeking financial backers[1] but only the one prototype Prop-Jet was built.[2]

Specifications

Data from Jane's All the World's Aircraft 1985–86[1] All performance figures at maximum take-off weight except where noted.

General characteristics

• Crew: One
• Capacity: Five passengers
• Length: 30 ft 7 in (9.32 m)
• Wingspan: 37 ft 10 in (11.53 m)
• Height: 10 ft 6 in (3.2 m)
• Wing area: 119.0 sq ft (11.06 m²)
• Aspect ratio: 12.02
• Airfoil: modified NACA 23016.5 at root, 23012 at tip
• Empty weight: 3,153 lb (1,430 kg)
• Max takeoff weight: 6,000 lb (2,722 kg)
• Fuel capacity: 220 US gal (832.5 L; 183 Imp gal)
• Powerplant: 1 × Pratt & Whitney Canada PT6A-41 turboprop, 550 hp (410 kW) derated from 634 kW (850 hp)
• Propellers: 4-bladed Hartzell Propeller Type HC-B4TN-3AL/LT1073F-12-5, 7 ft 6 in (2.29 m) diameter constant speed

Performance

• Cruise speed: 325 mph (523 km/h, 282 kn) economical, at 31,000 ft (9,450 m)
• Stall speed: 86 mph (138 km/h, 75 kn) flaps down,power off
• Range: 1,448 mi (2,330 km, 1,258 nmi) with maximum payload
• Ferry range: 1,544 mi (2,485 km, 1,342 nmi) with maximum fuel
• Service ceiling: 31,000 ft (9,400 m) service
• Rate of climb: 3,500 ft/min (17.8 m/s) at sea level at weight of 5,182 lb (2,350 kg)
• Wing loading: 50.0 lb/sq ft (244.1 kg/m²)
• Power/mass: 0.093 shp/lb (0.150 kW/kg)
• Take-off distance to clear 50 ft (15 m): 2,376 ft (724 m)
• Landing distance from 50 ft (15 m): 2,498 ft (761 m)

Avionics

• Collins nav/com, ADF, transponder
• Texas Instruments TI-9100C LORAN
• Full blind flying instrumentation

References

External links

• NACA 23012 airfoil