Written by David Andersen
As featured on page 58 in the March 2012 issue.
Read an except from the magazine and share your experiences.
Washout is a design characteristic built into the wing, where the angle of attack is reduced span-wise from root to tip, typically 1° to 2°. The reduction creates a situation where the root of the wing stalls before the tip, softening the stall and allowing the ailerons to be functional deep in the stall. Review some of the author's highlights from the magazine and share your experiences in the comment section below.
Washout is a twist in a wing that causes the wingtip to meet the airflow at a lower angle than the root in normal upright flight. Some airplanes don’t need it; some airplanes can’t fly without it.
Washout can be added after construction by slightly raising both ailerons. This is recommended for the maiden flights of a new model.
Bob Patton’s Cessna Aerobat uses drooped wingtips for stall control, typical of STOL aircraft.
The author’s Howard Pete has washout in only the last rib bay—enough for a nearly constant chord wing.
The glider-like wing of the author’s 114-inch span Focke Wulf Ta 152H requires washout for stability. The aircraft would be uncontrollable without it.
In case of engine failure, washout provides good yaw control in Greg Hahn’s B-17.
The author’s 1/3-scale Grumman Lynx has a constant chord wing with no washout. It instead uses Hoerner wingtips and stall strips, which are effective.
There’s no washout and no incidence in Dave Deschenes’ Wildcat—typical of constant-chord dive bombers.
Despite its thin, pointed wingtips, Dave Szabo’s Spitfire has excellent handling in part because of 2.5° of washout—roughly the same as the full-scale Spitfire. A low pass before a chandelle is shown here.
A 90° sharp-edge stall strip is added to the LE of the Grumman Lynx to lower the stall angle in the root area of the wing. This alternative to washout also works when inverted.
Leo Spychalla’s Ziroli Stuka has a gentle stall despite its pointed wings. The wings have 4° of washout, starting outboard of the landing gear.