Track v.s. Heading

[Michael Laggis]

Great explanation Don, That makes it perfectly clear.

Thanks
Michael Laggis 

________________________________

From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of Don Ramsey
Sent: Monday, June 06, 2005 2:53 PM
To: Discussion NSRCA
Subject: Track v.s. Heading


OK, here's my thoughts on heading and track.  They are very different terms.
Track is the path of the model over the ground.  Heading is the direction
the nose is pointed.  With no wind, heading and track are the same.  The
downgrades for some turnaround maneuvers are absolutely incorrect when there
is the statement, "Model heading does not finish exactly opposite direction
of entry."  
 
Let's take an example:
Say the course parallel to the flight line is north-south (360 or 180
degrees).  Assume the 180 degree heading is from left to right.  With no
wind, if the model is flying parallel to the flight line the heading and
track will be 180 degrees from left to right. Now assume an in blowing wind
that requires a 15 degree correction to maintain a path parallel to the
flightline.  Remember the track of the model must be wind corrected to track
parallel to the judges.  The heading is now 165 degrees but the track is 180
degrees.  The model is crabbed into the wind 15 degrees with the wings level
as required by our regs and the nose is pointed away from the pilot.  Now
assume you do a half loop as a turnaround.  The opposite heading to 165
degrees is 345 degrees.  And that heading points the model into the
flightline not away as would be required for wind correction.  How many
judges would award a perfect score if the model was pointed into the
flightline when an opposite correction was required?  These mis-stated
downgrades in the regulations have been ignored for years (at least I hope
they have).  Substitute track for heading and the model is now required to
exit the half loop on an exact opposite track.  In other words, parallel to
the flightline entering the maneuver and parallel to the flightline on exit.
 
Don
 
PS: On all modern jetliners the NAV display has pointers for both heading
and track and they are seldom the same in the air.


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