From: henry@monod.Biol.McGill.CA (Henry Pasternack)
Newsgroups: rec.models.rc
Subject: Re: Heli flight simulator.
Date: 14 Nov 92 03:28:51 GMT
Organization: McGill University


   I couldn't resist telling you about an interesting helicopter flight
simulator I had a recent opportunity to play with.  It's the Lynx Full
Mission Trainer at the Royal Navy helicopter base in Den Helder, Holland.
The simulator is built by CAE Electronics, Ltd., of Montreal.  Although
this isn't strictly about RC models, I thought some of you would find
it interesting.

   The simulator duplicates precisely the cockpit of the Lynx helicopter
used by the R.N.L.N. for anti-submarine and anti-surface warfare on the
North Sea.  It is installed on a full motion platform, and includes out-
of-cockpit visuals, sound effects and seat vibration.

   To start the helicopter, one first sets all of the electrical and
fuel system switches in the central ceiling control panel to their 'ON'
positions.  The two engine throttles are located on the front ceiling
and have red knobs on their ends.  Push in the knobs until they stick
and advance both throttles to their ground idle detents.  The turbine
temperature and RPM gauges will slowly come up to their normal starting
levels, at which point the starter buttons will pop out.  Advance the
number two throttle slowly to the full position, monitoring the gauges
to avoid excessive values.  Then advance the number one engine throttle.
Now retard the number one engine back to idle and switch the drive
selector from ACC to MAIN.  When the indicator clicks to MAIN, readvance
the number one throttle to full.  Adjust the torque and torque balance
controls so both engines show 20% torque.

   Unlock the wheels, turn on the navigation lights, engage the automatic
flight controls.  You're ready to go!  Keep your feet off the rudder
pedals to enable the automatic yaw position hold.  Gently pull up on
the collective and apply a little left cyclic.  See the runway lights
recede as the helicopter gains altitude.  Apply a bit more collective
and push the stick forward.  The Lynx picks up airspeed and begins to
climb.

   The helicopter is easy to fly with the flight control system engaged.
Separate pitch, yaw, and roll systems are selectable.  Turn them all off
and it takes very steady hands and feet to maintain a smooth flight.
In forward flight, the Lynx feels somewhat like a fixed-wing aircraft.
Apply some bank to initiate a turn and rudder to keep the nose pointed
into the wind.  A bit of back stick helps the helicopter come around
in a turn.  Pull back too much, and the Lynx runs out of airspeed.  There
is no stall buffet as one instinctly expects.  Instead, the helicopter
becomes very sensitive in yaw and difficult to control.  It is possible
to skid sideways or backwards, which is disconcerting.  The Lynx is
quite maneuverable and will do aerobatics, including barrel rolls.
Sorry, it doesn't fly inverted.

   You can try landing like a fixed wing (pick a pattern speed, fly
approach, downwind, base and final.  Touch down at 70 knots and
instantly die).  Proper landings are tough.  It's best to keep the
feet off the pedals and let the flight control system control the
heading.  Even so, it is difficult to maneuver over a precise landing
spot while maintaining height control with the collective.  I think
a nose-in hover is tough, even in the real thing.  The helicopter 
likes to bounce if you don't set it down smoothly.

   I wrote some software to created programmed sequences of
malfunctions.  One scenario simulates a missile strike.  For the
moment, it's triggered by pitching up the nose to 30 degrees.  A
sizeable chunk of the main rotor gets blown off, one engine catches on
fire and seizes.  For the next eight minutes, things get progressively
worse.  In the end, a hydraulic servo valve seizes and the stick slams
irreparably to the left.  The ground spins and rises up to meet the
Lynx.  It's quite alarming.

   The motion system is not used during simulator testing and
development for fear of emulating a paint shaker should something
go wrong.  You could easily be killed if the simulator started to
shake and you weren't belted in.  Even so, the illusion of motion
is quite convincing.  When the horizon tilts, it seems as though
the cockpit is turning in the opposite direction.  Without actual
motion cues, the inner ear and eyes conflict, producing a queasy
feeling in the stomach.  I tended to stagger out of the simulator
feeling dizzy for a few minutes.

   I'm hoping to fly an Apache simulator this December at Moffett
field in Mountain View, CA.  This simulator uses a helmet-mounted
display system for its visuals that senses pilot head position. 
If people are interested, and I get my chance, I'll write a report.

-Henry
Newsgroups: rec.models.rc