Abstract:
A compound helicopter is a hybrid vehicle, fundamentally a
helicopter. It uses an auxiliary lift and propulsion
device(s) in order to eliminate the lifting rotor high speed
limitation of retreating blade stall effects, thus allowing
flight characteristics comparable in many respects to those
of fixed-wing aircraft.
The primary objective of this thesis was to perform a design
study investigating the validity of the concept of
compounding, then selecting and designing a shaft-driven
single compound helicopter intended for use as a ground
support and anti-tank VTOL aircraft. The selection included
a complete parametric and sizing analysis which were based
on three defined maj or mission requirements: a maximum
forward speed of 250 knots; payload of 1500 lb and cruising
endurance of 3 hours at 225 knots.
Of the many configurations studied, a single-rotor compound
helicopter featured with convertible tail prop/rotor was
found to be the most suitable for the intended application.
Stability/control characteristics and performance capability
of the designed aircraft were found to meet or exceed
military specifications and flying quality requirements.
structure, dynamics and cost analysis were considered to be
beyond the scope of the design study.
