From: Tony P. <ton...@co...> - 2014-12-15 15:45:28
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Coefficients are normalized by the speed, not the velocity. The coefficients them selves define the direction in which they act. -- Tony Follow your heart, don't give up, and try like hell to not be stupid. Repeat when, not if, the latter occurs. > On Dec 15, 2014, at 5:46 AM, Elias Tarasov <eli...@gm...> wrote: > > Hello! > Situation: Datcom produces coefficients in the stability axis system. JSBSim requires it to be in a body or a wind axes. > Since body differs from stabilty only at the AoA, it seems rationally to convert stability to body. > The way to convert (assumption): > 1. Get coefficients from <Airplane_Name>.out file, produced by Datcom. > 2. Evaluate respective force or moment. > 3. Convert F or M into Body axis. > 4. Evaluate coefficients form the F or M that now in a body system. > > Is that way correct? Or there are some other ways do exist? > > The problem i have encountered: > > Since for instance F = qbar * S* C, then qbar is an obvious vector. > qbar = (1/2)*density*V^2. > So: > 1. When we do a step №2 and evaluate the Force wrt to Stability axis do we have to express V as a vector wrt to Stability? > 2. When we do a step №4 and evaluate the coefficients wrt to Body axis do we have to express V as a vector wrt to Body? > > These 2 questions seems an obvious, but since in Datcom we cannot input Beta, and don't have it in an output file, that means we > can't get or calculate the components of V and therefore can't get qbar wrt Body or Stability axes. > > Cannot find the solution at Stevens and Lewis and Datcom User Manual. > Can anybody point how to solve that problem? > > Thanks a lot and best regards. > ------------------------------------------------------------------------------ > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > with Interactivity, Sharing, Native Excel Exports, App Integration & more > Get technology previously reserved for billion-dollar corporations, FREE > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > _______________________________________________ > Jsbsim-devel mailing list > Jsb...@li... > https://lists.sourceforge.net/lists/listinfo/jsbsim-devel > _______________________________________________ > The JSBSim Flight Dynamics Model project > http://www.JSBSim.org > _______________________________________________ > |