The appearance in 1930 of the four-engined troop carrier (TC) TC.33 was a complete break from their tradition and was the only four-engined aircraft that Gloster ever built. It was designed led by Henry Folland to meet Air Ministry specification C.16/28, which required the ability to carry 30 troops and their equipment for 1,200 miles (1,930 km) and was the same specification that produced the Handley Page H.P.43 and the Vickers Type 163.
The TC.33 was a large single bay all-metal biplane with no stagger and 7° sweepback. Both wings had metal lattice spars and metal ribs with fabric covering. The lower wing was unusual in that its centre section had marked anhedral so that the main spars met at the top of the fuselage, leaving the interior unobstructed. The outer end of this centre section was strut braced to the lower fuselage. The TC.33 also had a lower wing of (slightly) greater span than the upper.
The four evaporatively cooled Rolls-Royce Kestrel engines were mounted in two nacelles, each containing a tractor-pusher pair together with their steam condenser and mounted between the wings at the end of the centre section. They were each carried by two vertical struts above the nacelle, complicated strutting below and by further strutting to the lower wing roots. The wide (22 ft 6 in (6.8 m)) split axle undercarriage had vertical legs from the front wing spar at the same point and bracing from the axles to the fuselage.
The fuselage was oval in cross section and smoothly metal skinned. The cockpit was enclosed, but there were open gunners' positions at nose and tail. Like the cockpit, the long main cabin was heated and soundproofed. There was a large hatch in the floor for heavy loads with an integral hoist mounted above it, plus a smaller roof hatch through which loads could be lowered by crane. The biplane tail unit had conventional fabric covered endplate fins and rudders, but the tailplanes were sesquiplane type. The upper tailplane and elevator was strut mounted above the fuselage and the much narrower chord lower part fixed to the lower fuselage.
The prototype was completed in January 1931 and, because the hangar doors were low, the undercarriage had to be assembled in two trenches. The aircraft was winched in and out of the hangar by way of these trenches.
The TC.33 first flew on 23 February 1932. Development flying showed it had good performance but suffered from elevator and rudder flutter. The former was cured with mass balancing but the rudder flutter persisted, particularly in high speed dives until the rudders were redesigned.
It was exhibited at the 1932 RAF Hendon Display and then went on to RAF Martlesham Heath for trials. Once in the air, the TC.33 was judged a pleasant machine to fly, but it was crucially let down by its full load take off performance. Even at Martlesham it was hard to get it off the ground in a reasonable distance. The undercarriage behaviour was also criticised. Because of these concerns over take off performance at English temperatures and altitudes, the Air Ministry did not place an order, judging it would not cope with the hot and high conditions found at many RAF fields across the Empire. Thus J9832 was the only one of its kind. None of the C.16/28 contenders were awarded a production contract.
Engines: 2 × Rolls-Royce Kestrel IIIS, 580 hp (432 kW) & 2 × Rolls-Royce Kestrel IIS, 580 hp (432 kW)
Props: 12 ft 6 in (3.8 m) diameter two bladed fixed pitch tractor & 11 ft 0 in (3.3 m) diameter two blade fixed pitch pusher
Length: 80 ft 0 in (24.38 m)
Wingspan: 95 ft 1 in (28.98 m)
Height: 25 ft 8 in (7.82 m)
Wing area: 2,493 ft2 (231.60 m2)
Empty weight: 18,399 lb (8,346 kg)
Gross weight: 28,884 lb (13,101 kg)
Maximum speed: at 13000 ft (3,960 m) 142 mph (227 km/h)
Service ceiling: 19,100 ft (5,821 m)
Rate of climb: to 10,000 ft (3,050 m) 408 ft/min (2.1 m/s)
Armament: 2 × 0.303 in (7.7 mm) Lewis gun, in front and rear positions & 3,600 lb / 1,633 kg bomb load on racks below fuselage
Capacity: 30 troops