Technical data

13773-001
53-10
Page 1
MAIN FRAME
1. DESCRIPTION
This section describes those structural components which make up the main frame including vertical stabi-
lizer, firewall, bulkheads, spar tunnel, and roll cage.
A. Firewall
The firewall is designed to separate the engine compartment from the rest of the fuselage and support
various airplane components on both the forward and aft sides. The firewall, constructed of a fiber-
glass composite sandwich, includes metal fittings for supporting the engine mount, and incorporates
several hardpoints for support of various engine components. In addition the firewall assembly also
supports the compression tube that is used to absorb CAPS deployment loads. Fire protection is pro-
vided by a layer of aluminum foil, FiberFrax paper, and a stainless steel sheet mounted on the bulk-
head’s forward side.
B. FS 222 Bulkhead
The FS 222 bulkhead is constructed of fiberglass composite sandwich and solid laminate. The upper
portion of the bulkhead is reinforced with additional fiberglass to support reaction loads during CAPS
deployment and to support passenger seat shoulder harness attachments. The bulkhead also contains
hardpoints which support cargo attachment loads.
C. FS 289 Bulkhead
The bulkhead at FS 289 is fabricated from fiberglass laminate. This bulkhead provides buckling sup-
port to the empennage.
D. FS 306 Bulkhead
The FS 306 bulkhead, located below the horizontal stabilizer, is fabricated from fiberglass laminate to
carry loads generated by the attached rudder/elevator actuation system.
E. Spar Tunnel
The spar tunnel is comprised of solid laminate and supports wing reaction loads. In addition, seat track
attachment channels are mounted to the front and rear face of the spar box.
F. Roll Cage
The roll cage is composed primarily of bi-directional fiberglass but also contains unidirectional fiber-
glass to add bending strength. The main structural components of the roll cage are side longerons,
which support in-flight bending loads, and hoop sections surrounding the right and left doors. The
remaining components provide local stiffening to cutout regions of the fuselage.
30 Nov 2000