Dimensions and Wing Geometry

Hangar planning, wingtip clearance and the figures an examiner expects at your fingertips all come out of one short table. Every number below is stated by the manual itself to be approximate — these describe the airframe, they are not tolerances.

At a glance

• Wing span11.63 m (38 ft 2 in)
• Overall length8.06 m (26 ft 5 in)
• Overall height1.97 m (6 ft 6 in)
• Wing area13.244 m² (142.6 sq ft)
• Mean aerodynamic chord1.171 m (3 ft 10 in)
• Aspect ratio10.223
• Dihedral5°
• Leading edge sweep1°
• AirfoilWortmann FX 63-137/20 - W4
• Aileron area (left and right together)0.654 m² (7.0 sq ft)
• Wing flap area (left and right together)1.56 m² (16.8 sq ft)
• Horizontal tail area2.34 m² (25.2 sq ft)
• Elevator area0.665 m² (7.2 sq ft)
• Horizontal tail incidence-3.0°
• Vertical tail area1.60 m² (17.2 sq ft)
• Rudder area0.47 m² (5.1 sq ft)

NOTE — All the dimensions in this lesson are stated by the manual to be approximate.

The three outside numbers

The wing spans 11.63 m (38 ft 2 in). The aeroplane is 8.06 m (26 ft 5 in) long and 1.97 m (6 ft 6 in) tall. Those three decide whether it fits through a hangar door and how much room a wingtip needs on a crowded apron.

Figure: General arrangement with principal dimensions (redrawn).

The three-view drawing itself carries only two dimension callouts — span 11630 mm (38 ft 2 in) and length 8060 mm (26 ft 5 in) — and both repeat the dimensions table exactly, in millimetres.

The wing

The wing uses the Wortmann FX 63-137/20 - W4 airfoil. It covers 13.244 m² (142.6 sq ft) with a mean aerodynamic chord of 1.171 m (3 ft 10 in) and an aspect ratio of 10.223. It is set with 5° of dihedral and 1° of sweep at the leading edge. The ailerons contribute 0.654 m² (7.0 sq ft) of area between them and the wing flaps 1.56 m² (16.8 sq ft).

The tail

The horizontal tail covers 2.34 m² (25.2 sq ft), of which the elevator is 0.665 m² (7.2 sq ft), and it is rigged at -3.0° of incidence relative to the longitudinal axis. The vertical tail covers 1.60 m² (17.2 sq ft), of which the rudder is 0.47 m² (5.1 sq ft).

Both tail surfaces are worth memorising as a pair with their control surfaces: the movable part is roughly a quarter to a third of each total, and the two totals are the figures most easily confused with one another.

Check yourself

• What are the wing span, overall length and overall height, and what does the manual say about the precision of all three?

• Which airfoil does the wing use, and what are its area and aspect ratio?

• How much dihedral and leading-edge sweep does the wing carry?

• At what angle of incidence is the horizontal tail set, and relative to what?

• Which two dimensions appear on the three-view drawing, and do they agree with the dimensions table?

Study aid — always fly your aircraft's current AFM/POH.