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From: Sky2high@aol.com
Date: Tue Mar 18, 2003 7:26:35 PM America/Detroit
Feathers, et al:
When one studies the SUN 100 course, it can be shown that ... 360 high speed turning degrees.
Using Fig 2.29 (Constant Altitude, Steady Turn Performance) in "Aerodynamics for Naval Aviators" (NAVWEPS 00-80T-80) on can find that at 200 KTAS and a 60 degree banked turn, the radius is 2000 feet. Thus, Pi x D = 12566 feet or 2.07 Nautical Miles.
The turning radius for 200 KTAS, 30 degrees is about 6000 feet or 3 times that of a 60 degree turn. Thus, taking turns at 30 degrees would add 6.2 NM to the course.
Grayhawk
N92EX
Grayhawk & Grease,
I finally thought that I would do the calculations in great detail for the Sun 100 Race. I used 7 points to calculate the distance. They were:
1) 500 ft from the touchdown end of runway 9
2) 500 ft past the end of runway 9
3) the SE GPS coordinates of the course
4) the SW GPS coordinates of the course
5) a point 1/4 nm W of the touchdown end of runway 9
6) the starting point
The total distance came out to be 77.1 nm. Being the course is listed at 82 nm, it looks like 4.9 nm was added to the course length or about 5 nm.
To verify this distance, I talked the Jerry Agular(sp) at Aircraft Spruce(AC). Jerry is in charge of the course.
I had Jerry explain why the course was listed as 82 nm. His response was that it had been listed at 82 nm since before there were GPSs or recorded history. He said that a few years ago the GPS coordinates were taken on the ground. The coordinates seemed to confirm that with turns the course was about 82 nm.
The exact distance of the Suffolk 100 is 87.5 nm. If we add about 5 nm to that we get 92 nm. We have listed on the Suffolk 100 web page that the course is 93 nm. The calculated speed differential caused by this one mile distance would be 92/93*200 = 2.2 kts. In other words, we would be showing higher speeds of about 2.2 kts when compared to the Sun 100 race.
I hate to recommend it but i think that we should set the Suffolk 100 course distance at 92 nm. With this setting our speeds will compare directly with the Sun 100 speeds.
Other opinions are welcome.
--
Lorn H. 'Feathers' Olsen, MAA, DynaComm, Corp.
248-478-4301, mailto:lorn@dynacomm.ws
LNC2, O-320-D1F, N31161, Y47, SE Michigan
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