Obsolete: revised on 11/7/04

for archive only

**West Coast Challenge
The Longest Flights
On Short Days**

Original posting 11/3/04

Updated 11/4/04 Rev A superseded by

Updated 11/6/04

This is obsolete Rev B, superseded by Rev C Dated 11/7/04

Our South Coast Flying is some of the best to be had on short days. To demonstrate, we offer a challenge to all unpowered foot launched aircraft on the West Coast. The winner will be determined by the formula:

**miles times x**

- Where
- Miles = Total straight line miles between two points over-flown by an unpowered aircraft that was foot launched from anywhere in one of the USA states that borders the pacific ocean (California, Oregon, and Washington)
- x = (cos(d/2)
^{2}- where d is calculated by subtracting 15 from the calendar day of the year and clamping d so that d is not less than zero or more than 360.

**Rules:***Aircraft*: any unpowered aircraft, but the launch method for the flight must be unassisted foot launch (no wheeled launches or towing, but you may use a people to assist without the aid of mechanical devices)*Entry Fee*: None*Registration*or prior declaration: None Required*Documentation*: A reasonably descriptive article must be posted to the SCPA flight discussion forum under the thread titled Challenge (thread date:11/3/04). Flight articles must be posted by the end of January, 2005.*Contest Period*: From Jan 1st 2004 through Dec 31st, 2004

**Prizes:**To be awarded by The Sundowner at the February SCPA general membership meeting (attendance not required)- 1st place flight $100
- 2nd place flight $50
- 3rd place flight $25

- The formula is not as bad as it looks
- Calculate "d" by taking the day of the year (counting up from Jan 1) and subtracting an offset of 15 (to stretch the middle and account for seasonal lag). Clamp the calculation so that d is not less that zero or more than 360.
- Divide "d" by 2 and take the cosine of that number (in degrees)
- Squaring the cosine causes the curve to fall off more aggressively in the midrange and then curve again the other direction toward an asymptote rather than a cusp. It also forces the result to be positive

Examples

- a 50 mile flight on Jan 1st
- d computes to 0
- x computes to 1
- 50 times x = 50 points

- a 100 mile flight on May 1st
- d computes to 107
- x computes to 0.3538
- 100 times x = 35 points

- 50 mile flight on Dec 21st
- d computes to 360
- x computes to 0
- 50 miles times x = 50 points

- a 50 mile flight on Feb 15th
- d = 31
- x computes to .9286
- 50 miles times x = 46 points

- a 75 mile flight on April 1st
- d = 77
- x computes to .6125
- 75 miles times x = 46 points

Auto Calculator Pending

Formula Adjustment Notes: We may need to increase the exponent in future years if late spring and early fall flight scores are better than those in the middle of the year. We can also tune the offset if deemed necessary. We'll see what happens for 2004 and likely run again in 2005.