Lorn Writes:

 

 I calculate the length of the Lakeland 100 mile race at 76.1 nm or 87.5 statute miles.

 Gentleman,

 

It is true that GPS distances are 6 miles less than course computed speeds.  I suspect that 2 miles were added to each of 3 x 120 deg turns (or 2 x 120 turns and 2 x 60 deg turns depending on how you look at it). 

 

This increase in distance is arguable based on speed & G (varying turn radii).  Although it has to be somewhat arbitrary (varying bank angle) , the fact that it exists is accepted and added to triangle courses.  No airplane that I'm aware of could simply turn on a dime (accept the NASA HARV-F/A-18)  We used to use a Combat Plotter in the Navy that had speed and bank angle distances.  It had 1 NM tick marks around the radius of the turn.  This way you could fly up to a visible turn point and turn with a known distance.  This would make low level ingresses accurate to within a few seconds with very little pilot skill required (which was very helpful to me of course). 

 

Hope this helps to clarify and minimize "the timers cheated" syndrome from lack of understanding.

 

Larrry Henney

N360LH

My plaque reads 209.96 Kts

I claim with a straight face that it flew and flys 210 kts.