Aero Boero AB-115 - Design

Design

The AB-115 is a high-wing monoplane, with strut-braced rectangular wings (NACA 23012 profile). The wing and nacelle are made of aluminum alloy, with fiberglass wingtips, while the rest of the fuselage and the empennage are made of welded steel tubes covered by fabric.

The trainer version, the most common variant, contains two seats in tandem configuration, with the pilot-flying/student pilot in the front seat, and the instructor/pilot-not-flying seating in the rear. Behind the rear seat there is a cargo hold, with capacity of up to 25 kg (55 lb). The front seat has a three-point seatbelt, while the rear one has a simple, abdominal belt. Both occupants enter and exit the aircraft through one single, large door in the right side of the cockpit.

The flight commands are duplicated, with the front seat's center stick, throttle lever, rudder pedals and brake pedals mechanically connected to the rear seat's. The rear stick and the throttle lever can be disassembled when carrying passenger(s).

The primary flight commands are actuated by cables and pulleys. The ailerons are made of aluminum alloy, while the rudder and elevators are made of steel tubes and fabric. The flaps have four positions (neutral, 15°, 30° and 45°), and are actuated manually, by a lever in the upper left part of the cockpit. The pitch trim tab is located in the trailing edge of the left elevator, and is actuated by a handle in the left side of the cockpit. The rudder and the left aileron also have trim tabs, bu these can only be adjusted on the ground.

A Lycoming O-235-C2A air-cooled engine, rated at 115 hp (87.5 kW), drives a Sensenich Propeller model 72 CK-050, metallic fixed-pitch twin-bladed propeller. The fuel injection system uses a FACET MA 3PA carburetor, equipped with carburetor heat. The engine is also equipped with one Prestolite alternator, two Bendix Scintilla S5LN magnetos and one Prestolite starter motor. The lubricant is stored within the engine's crankcase. The lubricant system also includes an oil radiator in the front of the engine's air intake, which is triggered by a bi-metallic thermostatic valve.

The maximum fuel capacity is 115 liters, while the actual useful load is 110 liters. The engine can be fed with either 80/87 octanes, 100LL or 100/130 octanes Avgas. There are two aluminum fuel tanks, fixed by metallic belts in the roots of each wing. The fuel load is displayed by two separate sight glasses, in both sides of the cockpit. There are two separate fuel selectors, for each tank, which can be independently opened and closed.

The aircraft features a conventional undercarriage. Each of the two main gears is fixed to the fuselage in three points - two articulated joints, plus one shock absorber. The wheels are made of aluminum alloy and magnesium, and are equipped with independent hydraulic-actuated brakes. The aircraft, however, doesn't have parking brakes - when parked, it must be necessarily secured by chocks. The tailwheel is connected to the rudder by two springs, but it can also rotate freely when "unlocked".

The instrument panel is relatively simple, since the AB-115 is mostly used for basic flight training. The included flight instruments are an airspeed indicator, altimeter, VSI and a turn coordinator. The engine's instruments are a tachometer, two gauges for oil pressure and oil temperature, and an ammeter for the alternator. For navigation, there is a magnetic compass. The panel also includes one Bendix/King VHF radio, and one Bendix/King transponder. The cabin is equipped with a flood light, which is turned on by the navigation lights' switch, and the luminosity can be adjusted by a potentiometer. The aircraft is also equipped with two landing lights, both on the right wing's leading edge, but these can not be used continuously for more than five minutes.