Photograph:
Bygate Tiger Hawk ZK-THK (c/n 1) at Omaka, New Zealand (David C Eyre)
Country of origin:
New Zealand
Description:
Single-seat light sport aircraft
Power Plant:
One 101 kw (130 hp) Subaru EJ-20 alloy, four-cylinder, horizontally-opposed, carburetted, engine driving through a belt reduction drive
Specifications:
- Wingspan: 7.26 m (23 ft 9 in)
- Length: 5.9 m (19 ft 3 in)
- Height to top of tail: 1.6 m (5 ft 3 in)
- Wing area: 8.08 m² (87 sq ft)
- Max speed at sea level: 259 km/h (161 mph)
- Cruising speed at 4,500 rpm: 185 km/h (115 mph)
- Cruising speed at 4,750 rpm: 204 km/h (127 mph)
- Cruising speed at 5,000 rpm: 213 km/h (132 mph)
- Stalling speed full flap: 56 km/h (35 mph)
- Initial rate of climb: 366 m/min (1,200 ft/min)
- Time to 1,372 m (4,500 ft): 4.5 mins
- Fuel capacity: 68 litres (15 Imp gals)
- Endurance: 3 hrs 40 mins
- Range: 754 km (468 miles)
- Wing loading: 13.88 lb/sq ft
- Loaded weight: 542 kg (1,195 lb)
History:
The Tiger Hawk was a small ultralight amateur-built sport aircraft designed and built by Mr Tim P D Bygate of Nelson, NZ. The first example was completed in 2002 and registered as ZK-THK (c/n 1), painted in an attractive Tiger colour scheme, making its first flight on 7 September 2001 at Hanmer Springs, North Canterbury.
The Tiger Hawk was a single-seat, low-wing monoplane of wood and fabric construction with a spacious cockpit, a compartment for luggage, a bubble canopy and large tyres to enable it to operate from rough fields. It had a spring-steel tailwheel undercarriage, a conventional tail and rudder, tailplane and elevator with electrical elevator and rudder trims. The cockpit had heating / cooling with a windscreen demister. Fuel was contained in two 34 litre (7.5 Imp gal) tanks, one in each wing.
If produced in quantity or as a kit, the aircraft was to be made available with three different engines, all from the Subaru EJ range. The Subaru EJ-20 provided 101 kw (130 hp) and was a four-cylinder double camshaft engine driving a three-blade Ivoprop through a SUB4 reduction box, considered to be the most suitable for the airframe. Other engines were the EJ-22 which provided 108 kw (145 hp) and EJ-25 which provided 127 kw (170 hp). All three engines are light alloy four-cylinder units with EFI, ‘link’ computer-controlled remotely from the cockpit, all units driving through the SUB4 propeller reduction gearbox [which was common to all Subaru EJ-20, EJ-22, EJ-25 and SVX-33 engines – the latter being a six-cylinder boxer type] using an Ivoprop medium three-blade ground-adjustable, carbon-fibre propeller with spinner.
During the development stage all three engines were fitted in the airframe and it was found the EJ-20 was the most successful, using 13.33 litres (2.93 Imp gals) per hour at economical cruise, and 17.5 litres (3.84 Imp gals) per hour for cross country work with a few circuits during consumption tests. All these engines were easily interchangeable.
The aircraft was not available in ‘kit form’ or ‘plans only’ form but construction drawings were to be available to provide a ‘plans only’ form if there was sufficient interest. Consideration was also given to installing the Subaru AE-81 63 kw (85 hp) all-aluminium four-cylinder boxer engine with a carburettor driving a two-blade wooden propeller through a belt reduction drive.