Airframe Construction-Helicopters

The airframe of the Helicopter covers a wide range of materials, mainly due to the advances in technology that have taken place in the 50 years since the first helicopters were manufactured. For the most part the materials used in helicopter construction are the same as those used in fixed wing aircraft.

There are 3 (three) basic types of construction normally used for the fuselage, tail cone and pylon, these are:

• Tubular or Truss type
• Monocoque or Semi-Monocoque type, Sheet Metal Construction
• Bonded Construction  

There are two types of tubular-truss construction, known as the PRATT TRUSS and the WARREN TRUSS.  In both cases the structure is built up around longerons which provide the main strength to resist Torsional and Bending loads

 

Aircraft Structure Zoning System

Zoning of large aircraft is specified by the Air Transport Association of America in the ATA-100 Specification.
A zone is identified by one of three indicators, depending upon whether it is a major zone, major sub-zone, or simply a zone.

 Major zones are identified by three digit numbers as follows:
Major Zone                                       Area
 No.                                 
100              Lower half of the fuselage to the rear pressure bulkhead (below the main cabin deck).
200              Upper half of the fuselage to the rear pressure bulkhead.
300              Empennage, including fuselage aft of the rear pressure bulkhead.
400              Power plants and struts or pylons.
500              Left wing.
600              Right wing.
700              Landing gear and landing gear doors.
800              Doors.
900              Reserved for uncommon differences between aircraft types not covered by standard series numbers.

The standard series is from 100 to 800 and the special series numbers are in the 900 bracket. \