X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-02.southeast.rr.com ([24.25.9.101] verified) by logan.com (CommuniGate Pro SMTP 5.1.2) with ESMTP id 1573163 for flyrotary@lancaironline.net; Thu, 16 Nov 2006 13:19:00 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.101; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-098-162.carolina.res.rr.com [24.74.98.162]) by ms-smtp-02.southeast.rr.com (8.13.6/8.13.6) with SMTP id kAGIIHvc015239 for ; Thu, 16 Nov 2006 13:18:20 -0500 (EST) Message-ID: <000501c709ab$98637160$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] FW: Where am I? Date: Thu, 16 Nov 2006 13:18:19 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 X-Virus-Scanned: Symantec AntiVirus Scan Engine Hey, what any engineer wants - a basic simply to understand explanation of a situation - or failing that a complete obstrufication of any possible useful information to where a normal person (or even an abnormal person) is completely dumbfounded by the brilliant juxtaposition of words to seeming mean something when it doesn't. I like it{:>). Ed ----- Original Message ----- From: "Mark R Steitle" To: "Rotary motors in aircraft" Sent: Thursday, November 16, 2006 11:05 AM Subject: [FlyRotary] FW: Where am I? While not specifically "rotary" in nature, I thought this would be of interest to at least few on the list. I suspect it was likely written either by a technical writer or an engineer. Enjoy... -----Original Message----- ==================================== A pilot gave the following explanation when asked, why in this age of FMS, GPS, RNAV, VNAV, ATC, and Inertial Nav, he got lost: "The aircraft knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is the greater), it obtains a difference, or deviation. The Inertial Guidance System uses deviations to generate error signal commands, which instruct the aircraft to move from a position where it is to a position where it isn't, arriving at a position where it wasn't, or now is. Consequently, the position where it is, is now the position where it wasn't, the Inertial Guidance System has acquired a variation. Variations are caused by external factors, the discussions of which are beyond the scope of this report. A variation is the difference between where the aircraft is and where the aircraft wasn't. If the variation is considered to be a factor of significant magnitude, a correction may be applied by the use of the autopilot system. However, use of this correction requires that the aircraft now knows where it was because the variation has modified some of the information, which the aircraft has, so it is sure where it isn't. Nevertheless, the aircraft is sure where it isn't (within reason) and it knows where it was. It now subtracts where it should be from where it isn't, where it ought to be from where it wasn't (or vice versa) and integrates the difference with the product of where it shouldn't be and where it was; thus obtaining the difference between its deviation and its variation , which is variable constant called "error"." -- For archives and unsub http://mail.lancaironline.net/lists/lml/ DO NOT ARCHIVE -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/