A~rcrnfl Publ~cnt~ons
Pipcr
Com:lnchc
250
(Early
Model)
Section
-
7
S!'stcrns
Description
SYSTEMS
DESCRIPTION
PA-24-250
*
2800
LBS
GROSS
WEIGHT
INTRODUCTION
The PA-24-250 Comanche is a high-performance, single-engine, low-wing, retractable-gear
monoplane of all-metal construction.
It
has four-place seating, two-hundred pound baggage
capacity, and a 250 horsepower engine with a constant-speed propeller.
AIRFRAME
The structures of the PA-24, except for the tubular-steel engine mount, steel landing-gear struts,
and other miscellaneous steel parts, are of sheet-aluminum construction, alodine treated and
completely primed with zinc-chromate primer, then covered with acrylic lacquer on the exterior
surfaces. The extremities (wing tips, stabilator and rudder end pieces) are constructed of fiberglass
or
ABS
thermoplastic. The fuselage is an all-metal semi-monocoque construction composed of
bulkheads, stringers, stiffeners and longitudinal beams to which the outer skin is riveted.
The laminar-flow wing is of all-metal stressed skin, full-cantilever design. The wing section is a
NACA
64, A215 airfoil with maximum thickness approximately forty-percent aft of the leading
edge. This permits the main spar to pass through the cabin under the rear seats, providing
unobstructed cabin-floor space. The extruded-beam type main spar is joined with high-strength
butt fittings at the center of the fuselage making in effect a continuous main spar. The spars are
attached to the fi~selage at the side and in the center of the structure. The wings are also attached
at the rear spar and at an auxiliary front spar. The ailerons are cable and push-rod controlled and
are statically and dynamically balanced. The trailing-edge wing flaps are manually operated. Flush
riveting is used over the forward part of the wing up to the main spar.
The all-metal empennage group is a full-cantilever design consisting of a vertical fin, rudder, and
stabilator with an anti-servo tab. The rudder and stabilator are statically and dynamically balanced.
The stabilator and vertical fin have two-channel main spars running
111
length. The stabilator is
attached to the fhelage by a torque tube supported by bearing blocks.
ENGINE
AND
PROPELLER
The Comanche 250 is powered by a Lycoming 0-540 series engine rated at 250 bhp, at 2575 rpm.
The 0-540 series engines are six cylinder, direct drive, wet sump, horizontally opposed, air cooled,
and have 541.5 cubic inches of displacement. The engine is designed to operate on 91/96
(minimum) octane aviation-grade fuel. Major accessories furnished with the engine are a geared
starter, 50-ampere, 12-volt generator, a vacuum pump, a direct-drive fuel pump, a wire mesh or
dry automotive-type carburetor air filter, and dual magnetos.
Engine cooling is accomplished without drag producing cowl flaps, exhaust augrnenters, or cowl
flanges.
An
external oil cooler is mounted in the front of the engine baffle.
The engine utilizes a Marvel-Schebler single-barrel, up-draft, float-type carburetor and
is
normally
aspirated. The carburetor is equipped with a manual mixture control and idle cut-off mechanism.
Copyright:
1993
Page
7-2
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