The Boulton Paul P.29 Sidestrand was an twin_engine biplane medium bomber of the Royal Air Force. Named after a village near Boulton Paul's factory in Norwich, the Sidestrand first flew in 1926 and entered service in 1928. It remained in service until 1936, only ever equipping one squadron; No. 101 Squadron RAF. It was an agile and relatively fast aircraft that was capable of aerobatic manoeuvres such as loops, rolls and spins.

Only 20 Sidestrands were ever built. The first two, essentially prototypes, were designated the Mk I. Originally intended to be powered by two Napier Lion inline engines, the Mk I was eventually fitted with 425 hp (317 kW) Bristol Jupiter VI radial engines which also powered the first six production Sidestrands, designated the Mk II. The remaining 12 aircraft were powered by 460 hp (343 kW) Jupiter VIIFs and were designated the Mk III. The six Mk IIs were also re-engined to bring them up to the Mk III specification.

The Sidestrand had three open defensive gun positions; nose, dorsal and ventral. The crew usually consisted of three personnel; pilot, nose gunner and a single gunner for the dorsal or ventral positions, the choice depending on where each individual plane was intended to fly in a formation. Armament for each position was a single .303 in (7.7 mm) Lewis gun. The Sidestrand's bombload was limited to 1050 lb (476 kg) which did not compare favourably with its contemporaries such as the Martin B-10.

In the early 1930s a Mk III Sidestrand was fitted with Bristol Pegasus IM3 engines. This was intended to become the Mk IV Sidestrand but eventually became the prototype for the redeveloped Boulton Paul Overstrand which would begin replacing the Sidestrand in service in 1936.

Specifications (Sidestrand Mk III)

General characteristics

• Crew: three or four; pilot & two/three gunners
• Length: 46 ft (14.02 m)
• Wingspan: 71 ft 11 in (21.92 m)
• Height: 14 ft 10 in (4.52 m)
• Wing area: 979 ft² (91 m²)
• Empty: 6,000 lb (2,726 kg)
• Loaded: 10,179 lb (4,627 kg)
• Maximum takeoff: lb ( kg)
• Powerplant: 2 x Bristol Jupiter 9-cylinder air-cooled radial engines, 460 hp (343 kW) each

Performance

• Maximum speed: 140 mph (225 km/h) at 10,000 ft (3,050 m)
• Range: 500 miles (805 km)
• Service ceiling: 24,000 ft (7,300 m)
• Rate of climb: 15,000 ft (4,572 m) in 19 minutes
• Wing loading: 10.4 lb/ft² (50.8 kg/m²)
• Power/Mass: 0.09 hp/lb (148 W/kg)

Armament

• 3 x .303 in (7.7 mm) Lewis guns in nose, dorsal and ventral gun positions
• 1,050 lb (476 kg) bombs

Related content

Related development: Boulton Paul Overstrand

Comparable aircraft:

Designation sequence: P.9 - P.29 - P.75 _ P.82 - P.108