lml@lancaironline.net Mailing List Archive

To find equivalent airspeed change for the same energy, look at the difference of the speeds squared 1/2 x m x((v + dv)^2-v^2). It doesn't take much change in forward velocity to generate the equivalent energy. This however ignores all the drag/time issues, so this calculation underestimates the speed increase required.

Chris

From: Colyn Case at earthlink <colyncase@earthlink.net>
To: lml@lancaironline.net
Sent: Thu, January 28, 2010 9:43:45 AM
Subject: [LML] Re: Airspeed sensing switch /Auto gear extension / Engine out gear down Issue!

Chris said,

AOA will compensate for weight very nicely. It doesn't know, however, what descent rate is being flown and how much energy is needed to arrest that sink. The energy needed goes up as a squared function of the vertical speed. In the 360, I span descent rates from 500 to 2,000 fpm on final (ILS to short approaches). The energy thus varies by a factor ~16. It is the higher end of the scale where one can get into trouble.

Is "energy" equivalent to mv^2 in this case?

so if you double your sink rate you would need to double your speed above stall to compensate?