Boulton Paul Balliol

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The Boulton Paul Balliol and the related Sea Balliol were monoplane military advanced trainer aircraft built for the United Kingdoms Royal Air Force (RAF) and the Royal Navy Fleet Air Arm (FAA) by Boulton Paul Aircraft. The Balliol was designed to replace the North American Harvard trainer and used the Rolls-Royce Merlin engine, with the Sea Balliol a naval version with folding wings and arrestor hook for training in deck landing.

1 Development
2 Operational history
3 Production
4 Operators
5 Specifications (T.2)
6 References
7 External links

[edit] Development

The Balliol was developed to meet Air Ministry specification T.7/45 for a three-seat advanced trainer powered by a turboprop engine, competing against the Avro Athena. The first prototype first flew on 30 May 1947, being temporarily powered by an 820 hp Bristol Mercury 30 radial engine. The second prototype, powered by the intended Armstrong Siddeley Mamba first flew on 17 May 1948, the world's first single engined turboprop aircraft to fly. ^[1] The Air Ministry had second thoughts about its training requirements, and issued a new specification, T.14/47, requiring a two seat trainer, powered by a Rolls-Royce Merlin engine.

The Merlin powered Balliol, designated Balliol T.2, first flew on 10 July 1948^[1], and after extensive evaluation, it was chosen over the Athena, with large orders being placed to replace Harvards in RAF service.^[2]

By 1951, however, the Air Ministry changed its mind about its training requirements yet again, and decided to introduce a jet-powered advanced trainer.

[edit] Operational history

Pre-production Balliols were delivered to the RAFs Central Flying School in 1950, but with the change in air-training policy, the Balliol was only delivered to one Flying Training School, -No 7 at Cottesmore, later serving at the RAF College, Cranwell. The Balliol served with the RAF until replaced by the de Havilland Vampire T.Mk.11 in 1956. ^[2]

[edit] Production

P.108 Balliol T.Mk 1

Prototypes. 3 built. Powered by Armstrong Siddeley Mamba

Balliol T.Mk 2

Two-seat advanced training aircraft for the RAF. 196 built, (166 built by Boulton Paul, and 30 built by Blackburn Aircraft).

Sea Balliol T.Mk 21

Two-seat advanced training aircraft for FAA. 30 built by Boulton Paul.

[edit] Operators

United Kingdom
- Royal Air Force
- Royal Navy, Fleet Air Arm].
Ceylon (Sri Lanka).

[edit] Specifications (T.2)

Data from Aircraft of the Royal Air Force^[1]

General characteristics

Crew: 2
Length: 35 ft 1½ in (10.71 m)
Wingspan: 39 ft 4 in (11.99 m)
Height: 12 ft 6 in (3.81 m)
Wing area: 250 ft² (24.2 m²)
Empty weight: 6,730 lb (3,059 kg)
Loaded weight: 8,410 lb (3823 kg)
Powerplant: 1× Rolls-Royce Merlin 35 V-12 piston, 1,245hp (929 kW)

Performance

Maximum speed: 250 knots (288 mph, 464 km/h) at 9,000 ft
Range: 574 nm (660 mi, 1063 km)
Service ceiling: 32,500 ft (9,909 m)
Rate of climb: 1,790 ft/min (9.1 m/s)
Wing loading: 33.6 lb/ft² (158 kg/m²)
Power/mass: 0.148 hp/lb (0.243 kW/kg)
Endurance 3 hours at 220 mph
Climb to 10,000 ft 6 minutes

Armament

One 0.303 in Browning machine gun
Provision for four 60-lb rockets.

[edit] References

^ ^a ^b ^c Thetford, Owen (1957). Aircraft of the Royal Air Force 1918-57, 1st edition, London: Putnam.
^ ^a ^b Donald, David (Editor) (1997). The Encyclopedia of World Aircraft. Aerospace Publishing. ISBN 1-85605-375-X.