Interservice/Industry Training, Simulation, and Education Conference (I/ITSEC) 2012
2012 Paper No. 12432 Page 1 of 11
Sideslip Misconceptions in Helicopter Simulators
Steven J. Smith
FlightSafety International Simulation
Broken Arrow, OK
steven.smith@flightsafety.com
ABSTRACT
Single rotor helicopters must have a means to balance the side force generated by the tail rotor. In hover, a slight
roll attitude tilts the main rotor thrust sideways to counteract the tail rotor translating tendency. But in forward flight,
a sideslip angle acting on the fuselage and vertical fin is commonly used to counteract the tail rotor effects. A non-
zero sideslip biases aircraft heading from the course and since there usually is no other frame of reference, pilots
assume this bias is instead due to a crosswind. Regardless, the net result is the same and pilots simply adjust head-
ing accordingly to track a course.
High fidelity training devices are designed to exhibit the same performance, handling qualities and instrumentation
as the aircraft. Therefore, as in the aircraft, non-zero sideslip angles in the simulator can result in pilots assuming it
is due to a crosswind. Unlike the aircraft, however, pilots (or instructors) in the simulator have direct control over
the winds and readily notice the difference between the wind effects they perceive and the simulated atmospheric
winds.
This paper describes how in the U.S. Army Flight School XXI UH-60L OFT simulator, this difference between per-
ceived and programmed winds was misinterpreted by pilots as a programming or instrument error in the device.
This perception resulted in the pilots rejecting the credibility of the simulator fearing it would result in negative
training habits. Many technical solutions were explored to unsuccessfully address a pilot perception problem. To
prove this concept, this paper presents flight test data from a fully instrumented UH-60M demonstrating the real
world difference between pilot perceived winds in the cockpit vs. ground based wind measurements.
ABOUT THE AUTHOR
Steven Smith is a Senior Staff Engineer at FlightSafety Simulation. In his 17 years at FlightSafety, Steven has been
involved with the design, implementation and regulatory approval of real-time, high fidelity, flight dynamics models
for fixed and rotary wing flight simulators. Steven holds Bachelor and Master of Science degrees in Aerospace En-
gineering from the University of Kansas.
