In aviation maintenance, "level" is flat. When you weigh an aircraft to determine empty CG, for instance, it is placed on jacks and leveled--both along the X-axis and along the Y-axis as well. However when an aircraft such as the 172 is sitting (empty) on a ramp, the "pitch attitude" is determined in large part by the inflation of the oleo nose strut. With the proper oil quantity and nitrogen gas inflation, the strut will be extended by some distance. As the main gear legs are relatively rigid, it is therefore the nose strut that will determine the angle in question. In Aviation Maintenance school, we were taught that the proper distance is "about a pack of cigarettes," which is about 3 inches give or take, and allows for a compromise of view over the nose during ground operations, and the avoidance of bottoming of the strut upon landing. However to some degree, there is a range of acceptable values--and one person's "pack of cigarettes" is another's cigar, I suppose. Never having been a smoker I simply measured it at about three inches, and this is the value I always tried to achieve. But I stress that this is only a guideline, as it is rare to achieve an *exact* degree of extension; simply due to the nature of the process. And as soon as the pilot/copilot/passengers get into the aircraft, this amount changes of course.
That being said, I believe that I do have access to service manuals for the 172-series of aircraft. Although I don't work in the industry any longer, several friends do--and I could likely get the proper dimensions from one of them without any difficulty. I will make a couple phone calls and report back in a day or so. Given the limitations of setting the exact oleo strut inflation, I would simply recommend that the nose angle be computed and set based upon the dimensions given in the Cessna drawings, which *should* be available in the service manual. TB ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
