X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [66.94.81.250] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 5.0c1) with HTTP id 668928 for lml@lancaironline.net; Sun, 14 Aug 2005 18:03:26 -0400 From: "Marvin Kaye" Subject: Re: torqued to death To: lml X-Mailer: CommuniGate Pro WebUser v5.0c1 Date: Sun, 14 Aug 2005 18:03:26 -0400 Message-ID: In-Reply-To: <001d01c5a0e1$60581c00$680a0b3e@interbusiness.it> References: <001d01c5a0e1$60581c00$680a0b3e@interbusiness.it> X-Priority: 3 MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Posted for "Robert Overmars" : Brent Regan wrote: "Given the 745 available horsepower (near sea level) and the 2,067 RPM prop speed I calculated an engine reaction torque of 1,893 foot pounds, roughly the same as putting a 200 pound weight about mid span on the aileron" No argument about that Brent but I think there's more involved. To counter the torque the pilot manipulates the control to drop the port aileron for more lift on that side. Corresponding to that, the stbd aileron is raised and reduces the lift on the stbd side, so to balance the torque we have an increase of lift on the port side but a reduction of lift on the stbd. Lets for the sake of the illustration say that the increase of lift on the port outboard section is 100lbs and the reduction of lift on the stbd outboard section is 100 lbs we've balanced the torque but have a net reduction of lift by 100lbs necessitating a small increase in pitch AoA to produce 100lbs more lift to maintain a stable flight path. Now in this situation we have a slight increase in AoA, plus the port aileron is lowered which results in the port outboard section working at a higher coefficient of lift but which brings it closer to the stalling AoA. Remember basic training? ...drop an aileron and the upwash angle at the wingtip increases. With more upwash on the port outboard section than on the stbd which brings it closer to the stalling AoA than the stbd, pull more backstick to flatten out the flightpath.... and I'm getting that that queasy feeling down in the stomach just in this little thought experiment. Then it gets really messy when considering P factor and prop wash on the vert stab, need a Cray brain to work all that out. Blame it on the Sunday run endorphins.... ciao, Roberto d'Italia.