Breda Ba.32

Breda
Industry	Aerospace
Headquarters	Italy

Template:Infobox aircraft

The Breda Ba.32 was a prototype airliner developed and manufactured by the Italian firm Breda.^[1]

This aircraft featured a low-wing trimotor monoplane configuration, equipped with fixed main landing gear covered by streamlined fairings. Propulsion was provided by three nine-cylinder air-cooled radial engines of the Pratt & Whitney R-985 Wasp Junior type. The crew consisted of two members, while the cabin was designed to carry up to ten passengers.^[1]

The Ba.32 prototype made its inaugural flight in 1931 and displayed promising handling qualities during test flights. Despite these positive results, the aircraft did not secure any production contracts, resulting in no further units being manufactured.^[1]

Design and development

The Breda 32 incorporated several advanced aerodynamic and structural elements for its time.^[2] The pursuit of aerodynamic refinement was balanced carefully with essential structural requirements. Additionally, the interior included various comfort features to meet operational expectations comprehensively.^[3] The fuselage exhibited sleek and aerodynamically efficient contours, shaped through experimental work related to the Breda CC.20 and extensive wind tunnel testing specific to this model.^[2] Particular attention was given to components such as the central engine cowling—which enclosed the exhaust manifold—the windshield, and the upper cockpit section, all optimized for minimal aerodynamic resistance.^[3]

The aircraft was outfitted with a low-mounted cantilever wing characterized by a relatively high aspect ratio and tapering in both planform and thickness along its span. This wing closely resembled one designed for a larger trimotor project underway at Breda during the same period, differing primarily in scale.^[2] Its design aimed to maximize aerodynamic efficiency while ensuring strong lateral stability, achieved through a pronounced dihedral angle. Lateral control was provided by large ailerons occupying about half of the trailing edge; their hinges were aligned to provide partial aerodynamic balancing.^[2]

The streamlined nacelles housing the two outboard engines were smoothly integrated into the wing structure, with propellers positioned ahead of the leading edge to reduce induced drag and minimize aerodynamic interference. The outboard engines were slightly angled inward toward each other, enhancing fin and rudder effectiveness and compensating somewhat for asymmetric torque if one engine failed.^[2] The tail unit's fixed surfaces were relatively thin and supported by streamlined steel struts, wires, and bars.^[3] Each tail surface’s framework consisted of two duralumin spars riveted to duralumin ribs and covered with metal skin; both rudder and elevator surfaces were aerodynamically balanced.^[4]

The landing gear comprised two wheels located beneath the outboard engines, partially enclosed within fairings that caused minimal drag interference with the wing.^[3] Each wheel was equipped with compressed air-operated brakes capable of differential application, facilitating tight ground maneuvering thanks to their wide track spacing.^[5] Shock-absorbing struts connected the gear to the airframe, while a tail wheel fitted with a balloon tire was mounted on a swiveling fork.^[5]

Constructed entirely from metal, both the airframe’s internal structure and exterior skin utilized all-metal techniques.^[3] The fuselage framework consisted of four steel tubular longerons combined with duralumin lattice frames to which riveted metal sheeting added rigidity.^[3] These primary fuselage components shared similarities with the wing spar design. Spherical joints connected sections of both fuselage and wings, allowing for easy disassembly and rail transport.^[3] The wing’s internal structure featured a single square-section spar supported by multiple ribs and covered by metal skin; this innovative design was protected by several patents.^[3] Positioned at the wing’s thickest point, the spar provided substantial resistance against torsional and bending forces. Stamped light sheet duralumin formed the ribs, which attached directly on either side of the spar.^[3] The wing covering was riveted to rib flanges; its rigidity was enhanced by stamped corrugations in the metal skin. Static tests confirmed that this covering contributed significantly to overall wing strength.^[3]

Powerplant installation consisted of three nine-cylinder Pratt & Whitney Wasp Junior radial engines.^[6] Each air-cooled engine featured a crankcase cooling regulator to maintain proper oil temperatures. Twin-bladed metal propellers adjustable on the ground were fitted to all engines.^[6] Engines were mounted on bearers made from welded steel tubing with bolts, rubber sockets, and buffers providing vibration isolation.^[5] These bearers attached either directly to the fuselage or wing spar depending on engine position. Engine cowlings were also mounted on these bearers independently of fuselage or wing structures and could be opened easily via multiple hooks for maintenance access.^[5] Numerous inspection ports located beneath the fuselage and within wings allowed monitoring of piping and controls.^[5] Oil systems operated independently for each engine and employed air cooling.^[5]

Fuel tanks resided within separately ventilated compartments in the wings outboard of each engine nacelle. Each tank included pilot-controlled dump valves as well as stopcocks regulating fuel flow.^[5] The fuel system incorporated a collector pocket supplying delivery pipes feeding each engine, manual pumps, plus a pair of gravity tanks sized to sustain flight should other tanks be compromised or pumps fail.^[5] Brass construction facilitated easy removal of tanks through access panels in wing surfaces. Large steel pipes interconnected tanks enabling simultaneous refueling via a single point.^[5]

Passenger access was generally through a wide door; an emergency exit could be installed based on customer preference.^[6] Typically configured for eight passengers seated three per side plus two on a rear sofa; up to three additional central tip-up seats could increase capacity to eleven seated occupants.^[6] Side seats were spaced to allow adjustable backrests enhancing comfort. Cabin illumination came from two rows of windows per side fitted with triplex safety glass panes that could be opened during flight.^[6] Heating was supplied by air drawn from the central engine’s exhaust manifold. Interior walls and seats were upholstered with fabric edged in leather; cushions contained feather filling covered with fabric-leather combinations. Carpeting covered cabin floors while overhead racks provided baggage storage alongside two spacious compartments fore and aft capable of holding up to 200 kg (441 lb.) each.^[6]

The cockpit offered excellent forward and lateral visibility featuring adjustable glass panels allowing pilots to extend their heads outside if necessary.^[6] Two leather-covered seats accommodated pilots while smaller chairs served flight engineer and radio operator positions. Linoleum covered cockpit flooring; walls combined leather and fabric upholstery.^[6] Night operations benefited from several reflecting lamps in cockpit plus indirect lighting within passenger areas.^[7] Instrumentation included luminous markings; external lighting comprised landing lights concealed within wings operated via cockpit lever during landing phases alongside navigation lights. Electrical power derived from a generator driven by central engine supplemented by a substantial battery backup ensuring current supply if generator failed.^[7] Electrical systems powered starter motors for engines as well as lighting and radio equipment; radio featured both fixed and movable antennas. Navigation instruments met requirements for operations under adverse weather conditions enabling instrument flight capability.^[7]