---------------------------------------------------------- RV10-List Digest Archive --- Total Messages Posted Tue 01/26/16: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:09 PM - Re: Numbers (dmaib@me.com) 2. 05:27 PM - Re: Numbers (Bob Turner) 3. 07:34 PM - Re: Re: Numbers (Kelly McMullen) 4. 08:34 PM - Re: Numbers (Bob Turner) ________________________________ Message 1 _____________________________________ Time: 03:09:19 PM PST US Subject: RV10-List: Re: Numbers From: "dmaib@me.com" Checked today and GRT Hxr allows display of TAS VNE as IAS. So, today at 3500 feet msl and about 12 degrees C, my VNE was shown as about 191 KIAS. I haven't had a chance to check that on the whiz wheel, but the number seemed reasonable. -------- David Maib RV-10 #40559 New Smyrna Beach, FL Read this topic online here: http://forums.matronics.com/viewtopic.php?p=452319#452319 ________________________________ Message 2 _____________________________________ Time: 05:27:24 PM PST US Subject: RV10-List: Re: Numbers From: "Bob Turner" I'm sure Vans' lawyers are telling him to never say anything, but I do wish the company was a little more forth-coming. Was the prototype dived to some speed? At what altitude (surely higher than sea level)? This whole business of specifying Vne as a TAS, when the FARs require specifying it (along with altitudes, if necessary) in IAS for normally certified aircraft, just bothers me. PS Dave, your ias/tas conversion looks about right to me. -------- Bob Turner RV-10 QB Read this topic online here: http://forums.matronics.com/viewtopic.php?p=452329#452329 ________________________________ Message 3 _____________________________________ Time: 07:34:19 PM PST US Subject: Re: RV10-List: Re: Numbers From: Kelly McMullen Van's has a white paper on the subject on their website. Thy physics say the design flutter speed is a function of TAS. They make the case that extra horsepower via turbo or other engine mods risks being able to exceed the number in level cruise at altitude around 12K and up. Type certified aircraft have to convert that to IAS with some empirical evidence of margin of safety via dive testing. Doing the testing is likely to be rather expensive by the time you instrument the airframe, mount drag chutes, quick release doors and risk loss of the aircraft if calculations are wrong. While loss of an aileron is relatively benign, loss of elevator or rudder is considerably more serious. On 1/26/2016 6:18 PM, Bob Turner wrote: > > I'm sure Vans' lawyers are telling him to never say anything, but I do wish the company was a little more forth-coming. Was the prototype dived to some speed? At what altitude (surely higher than sea level)? This whole business of specifying Vne as a TAS, when the FARs require specifying it (along with altitudes, if necessary) in IAS for normally certified aircraft, just bothers me. > > PS Dave, your ias/tas conversion looks about right to me. > > -------- > Bob Turner > RV-10 QB > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=452329#452329 > > ________________________________ Message 4 _____________________________________ Time: 08:34:55 PM PST US Subject: RV10-List: Re: Numbers From: "Bob Turner" Kellym wrote: > Van's has a white paper on the subject on their website. Thy physics say > the design flutter speed is a function of TAS. They make the case that > extra horsepower via turbo or other engine mods risks being able to > exceed the number in level cruise at altitude around 12K and up. > > [/quote] I've read the white paper. It contains a certain amount of nonsense. Flutter depends on TAS and air density. IAS depends on TAS and density. So between TAS, IAS, and density one can choose any two to express the equations. For example, with lift, we often choose IAS and density, because the density magically drops out of the equations. Does this mean lift doesn't depend on density? Of course not. It's included in just the right way in the definition of IAS. Now with flutter, there are many possible modes, and the relationship between density and TAS varies from one mode to the next. So it is not possible to define it away for all cases. You need, in general, two variables. It is not correct to say "flutter depends on (only) TAS". This business of higher than standard power is a red herring. Any standard -10, when light, can climb well into the flight levels. Nose it over to come down, and you can easily get as high a speed as desired. I would like to know, whether thru analysis or testing, where certain airspeeds (IAS or TAS) AND densities need to be observed as limiting. -------- Bob Turner RV-10 QB Read this topic online here: http://forums.matronics.com/viewtopic.php?p=452335#452335 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv10-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV10-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv10-list Browse Digests http://www.matronics.com/digest/rv10-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.