Huntair Pathfinder II
Single-seat single-engined high-wing monoplane with conventional three-axis control. Wing has unswept leading edge, swept for-ward trailing edge and tapering chord cruci-form tail. Pitch control by elevator on tail; yaw control by fully flying rudder with additional fin; roll control by half-span ailerons; control inputs through stick for pitch/roll and pedals for yaw. Wing braced from above by kingpost and cables, from below by cables; wing profile, modified 23012; 100% double-surface. Undercarriage has three wheels in tricycle formation with additional tailwheel; no suspension on nosewheel and steel-spring suspension on main wheels. Push-right go-right nosewheel steering connected to yaw control. No brakes. Aluminium-tube framework, with optional pod. Engine mounted below wing driving pusher propeller. Aluminium tubing to British HT3OTF specification. Polyester sailcloth.
The Pathfinder II is similar in concept to the Pathfinder I and is a logical development of the previous design. Visually the most obvious difference is the large diameter single upright, which replaces the two uprights originally used, but there are many other changes too. A fully double-surface wing is used, with curved underside, lower camber (3%), 12% aerofoil, shorter span and slightly lower area, changes which make the aircraft less affected by turbulence and, as a bonus, faster.
To improve handling, rigid ailerons are used, constructed similarly to the tail surfaces of the Pathfinder I The rudder has been made smaller and the fin area larger. Although the 330 engine is unchanged internally, the mounting system has been changed to reduce vibration and the fan-cooling dispensed with, saving weight and increasing power. Other improvements are the inclusion of a carburettor heat facility and a more durable design of drive shaft.
The combined effect of these changes is an aircraft which is faster, lighter and more compact than its predecessor. Although the pod remains optional, it is a standard fitment.
Steve Hunt designed the wings of the Pathfinder II to fold in four minutes, allowing the aircraft to be stored in a small space without being totally dismantled.
Engine: Robin EC34, 35 hp at 6500 rpm.
Propeller diameter 54 inch, 1.37 m.
V-belt reduction, ratio 2.4/1.
Max static thrust 210 lb, 95 kg.
Power per unit area 0.24 hp/sq.ft, 2.6 hp/sq.m.
Fuel capacity 5.4 US gal, 4.5 Imp gal, 20.4 litre.
Length overall 21.0 ft, 6.40 m.
Height overall 8.5ft, 2.59m.
Wing span 29.0ft, 8.84m.
Chord at root 5.3ft, 16.3m.
Chord at tip 4.5ft, 1.37m.
Dihedral 1 deg
Sweepback 0 deg
Total wing area 146 sq.ft, 13.6 sq.m
Wing aspect ratio 5.8/1.
Wheel track 4.4ft, 1.34m.
Nose-wheel diameter overall 13 inch, 33 cm.
Main wheels diameter overall 13 inch, 33 cm.
Optional floats, dimensions: 12 ft, 3.66 m long.
Optional skis, dimensions 3.8 ft, 1.16 m long.
Empty weight 260 lb, 118kg.
Max take-off weight 540 lb, 245kg.
Payload 280 lb, 127 kg.
Max wing loading 3.70 lb/sq.ft, 18.0 kg/sq.m.
Max power loading 15.41b/hp, 7.0kg/hp.
Load factors: +6.0, -4.0 ultimate.
Max level speed 80 mph, 129 kph.
Never exceed speed 90 mph, 145 kph.
Max cruising speed 75 mph, 121 kph.
Economic cruising speed 60 mph, 97 kph.
Stalling speed 26 mph, 42 kph.
Max climb rate at sea level 500 ft/min, 2.5 m/s.
Take-off distance 300 ft, 90 m.
Landing distance 300 ft, 90 m.
Service ceiling 12,000 ft, 3660 m.
Range at average cruising speed 180 mile, 290 km.