>The spinner is used because all your numbers are positive, since most people >have a hard time with negative numbers ( long time from algebra in school I >guess). Piper does the same thing. Cessna uses the firewall. The nice thing >about the firewall as the Datum line is that in most cases it will not move >or change.
An easy fix which will give all positive numbers is to put the "Zero" point well in front of the aircraft so that an easily remembered # (say 50" or 100") is used for the firewall (or any other fixed point). This means that the location for engine oil, prop., etc. will still be a positive # which can be figured by simple subtraction. Example: Prop. is 35" forward of the firewall, which is considered to be 100"; therefore, the moment for the prop. is 65". I can't claim this as an original idea since most Sikorsky Helicopters are figured that way. Allen G. Wiesner KR-2SS/TD S/N 1118 65 Franklin Street Ansonia, CT 06401-1240 (203) 732-0508 flash...@usadatanet.net
