Original article
JDMS
Journal of Defense Modeling and
Simulation: Applications,
Methodology, Technology
9(4) 347–360
Ó 2011 The Society for Modeling
and Simulation International
DOI: 10.1177/1548512911422240
dms.sagepub.com
Evaluation of visual cues of three-
dimensional virtual environments for
helicopter simulators
Ya se mi n C¸ etin, Erdal Yıı lmaz, and Yasemin Yardıı mcıı C¸ etin
Abstract
Visual cues are an essential part of helicopter flight simulators. The required cues for hover are particularly large, due to
closeness to the ground and small movements. However, the research on low-altitude helicopter flight is limited. In this
research, the density and height of the three-dimensional (3D) objects in the scene are analysed to find their effect on
hovering and low-altitude helicopter flight. An experiment is conducted using a personal computer-based flight simulator
on 10 professional military pilots. The results revealed that 3D object density and 3D object height affect both horizontal
and vertical hovering performance. In hover and low-altitude flight, altitude control is positively affected by smaller
object height. Paradoxically, the pilots preferred the scenes composed of tall and mixture objects. Pilot distance estima-
tion was significantly affected by the knowledge of both object density and object height, but these factors do not indivi-
dually improve distance estimation.
Keywords
flight simulator, helicopter, hover, low-altitude flight, three-dimensional object, visual cue
1. Introduction
Helicopter flight simulators are used in military, commer-
cial and civil aviation for training, research and develop-
ment. Simulators offer advantages to the users in terms of
safety, availability, versatility and cost saving. They can
also provide the opportunity for training in unlikely and
emergency situations. Personal computer-based flight
simulators (PC-FSs) are an alternative to enhanced flight
simulators with their low cost and portability.
With the improvement in PC and Internet technologies,
simulators have improved rapidly and are more wide-
spread. Wider use also brings up new questions about
simulators in terms of their reliability, validity and risks.
Studies
1–3
show that PC-based simulators affect some
stages of aircraft flight training positively. Examples of
these stages are procedural training, recurrent training,
instrument training and new tasks. However, lack of fide-
lity gives rise to longer training time and relearning of
some manoeuvres.
D’Alessandro
1
conducted a literature survey about the
effectiveness of PC-based simulators. He stated that
previous studies indicate positive training transfer from
PC-based simulators to real aircraft.
The negative transfer of training from the simulator to
a real flight environment is a serious problem. Effective
flight simulators provide pilots with cues that are equiva-
lent to those of the real world. Therefore, the necessary
visual and peripheral cues should be clarified in order to
determine the effectiveness of PC-based flight simulators.
Identification of the Out the Window Scene (OTWS) cues,
adequate for performance and bringing minimum system
load, is a concern for designing an optimized simulator
balancing effectiveness and cost.
Middle East Technical University, Ankara, Turkey
Corresponding author:
Yasemin C¸ etin, METU, Informatics Institute, Information Systems
Department, 06531, Cankaya, Ankara, Turkey.
Email: ycetin@ii.metu.edu.tr
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