Inertial Measurement Unit, rate of inertia, angular momentum ?????? I dont have a clue what you guys are talking about. All I know is you go out, turn the heli on, let the HH gyro, inertial measurement unit, angular momentum indicator, or what ever you want to call the thing initialize, fire up your heli and and go fly. The damn thing always keeps my heli pointed in the right direction and thats enough for me! How people flew w/o them in the early days is beyond me. To make this sailplane related- if you want to exercise that left thumb, fly helis for a while. Then go back to your sailplane and turn off that aileron/rudder mix- you may find using that left thumb isnt such a chore after all. Walter --- GG
On Sun, 16 Feb 2003 15:58:06 Jim Thorne wrote: >Rob- > >The name "inertial measurement unit" is completely correct, and it >doesn't depend on a second order effect. The problem with your earlier >statement was your reference to a "rate of inertia," which doesn't >exist. The rate information you mention below has to do with changes in >angular momentum. But, I said that before. I'll be happy to discuss >this further offline, if you like. > >Happy trails to you, too... >Jim > > >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] >Sent: Sunday, February 16, 2003 3:10 PM >To: [EMAIL PROTECTED] >Cc: [EMAIL PROTECTED] >Subject: [RCSE] Re:gyros - inertia vs. momentum > > >Jim - > >You sound like a physicist. > >You are right, in a way. Objects at rest do have inertia. Inertia is >what makes them want to remain at rest. We use inertial sensors to >detect this resistance, and we can infer both vector and rate >information from the right kind of sensors. There are sensors that >detect Doppler shift in a light beam to give the same information, but >they are pretty pricey and not commonly used in commercial or hobby >applications. > >Most folks who work with them would call a gyro or an accelerometer an >inertial sensor. The black box that lives in a spacecraft, missile, >submarine, car, or plane that spits out the data to tell the flight >computer where it is and where it is going in space is commonly called >an inertial measurement unit. It may not be strictly correct, and it may >be second order, but it works. > >happy trails - Rob > > > >Inertia is a property of matter that does not depend on motion, so there >is no such thing as a "rate of inertia" for a gyro to measure. Inertial >properties of an (intact) object do not change with rotation or >translation, but the momentum can change at some rate when forces are >applied. So, one could say that a gyro senses the rate of change of >angles from an angular momentum vector that is supposedly fixed in >inertial space. For that matter, inertial space doesn't actually exist, >according to general relativity. One possible exception is my own set >of inertial properties, which seem to be increasing as I get older and >sit motionless in front of the computer too much... > >Jim Thorne >in wintry Arlington, VA > > > > > ____________________________________________________________ Get 25MB of email storage with Lycos Mail Plus! Sign up today -- http://www.mail.lycos.com/brandPage.shtml?pageId=plus RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
