The Cessna 172R is an all-metal, high-wing monoplane which, unlike the more-recently designed pretenders to its throne, is utterly conventional in design.
The wing is a simple two-spar structure of 10.29m span, built in two halves which are bolted to the cabin frames and joined by a carry-through structure in the cabin roof. The rear spar extends only as far as the half-span of the long Frise-type ailerons, and the channel-section main spar is stiffed from the wing root to just outboard of the mounting points of the single diagonal bracing struts. The rest of the wing structure uses pressed ribs and rivetted, stressed skins, with glass-fibre-reinforced plastic end-caps. The inboard end of each half-wing forms an integral fuel-tank, each side having a capacity of 95litres and being filled through an over-wing gravity filler.
The single-slotted flaps are driven by an electric motor and screw-jack housed just in front of the rear spar of the starboard wing, and linked to the opposite flap by cables running through the cabin roof. The ailerons are connected directly to the control yoke forward of the two control wheels by cables, as is the two-piece elevator on the simple two-spar tailplane. While the ailerons have internal mass-balances, the elevator has horn balances.
There is a flight-adjustable trim-tab on the starboard side of the elevator. There is also a trim tab on the rudder, mounted on the simple two-spar vertical stabiliser, but this tab can only be adjusted by bending while the aircraft is on the ground.
The fuselage is an extremely simple semi-monococque structure, based around eight frames and large single-piece upper and lower skins. It terminates at its forward end in a stainless-steel firewall, to which is attached the mounting-frame for the Textron Lycoming IO-360-L2A four-cylinder engine and its all-metal two-bladed, fixed-pitch McCauley propeller.
The fixed tricycle undercarriage consists of a "Land-O-Matic" sprung, cantilever main leg unit, and an oleo- strut-mounted nosewheel. This nosewheel is mechanically steered through the rudder pedals, and the mainwheels have hydraulically operated disc brakes.
Source: Flight International
