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Using thrust data in the propeller XML file

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Using thrust data in the propeller XML file

Postby WittyOldman » Fri Mar 23, 2018 8:56 am

I have got the actual thrust data, a 3D table, of an aircraft. As I went through the C172p aircraft's XML files, I understood that it is using Thrust Coefficient (C_THRUST table) and finding the thrust.

How to integrate the actual thrust data, into the XML file? Do I need to edit the FGPropeller.cpp file, so that instead of finding thrust using a mathematical formula, it can take it directly from the lookup table?

I don't have a clear picture of the property tree and how it works. Anyway, I tried editing the aircraft's propeller XML file, present in the Engines folder of C172p, only to get some osg error.

If anybody can help a bit, that would be really appreciable. Thank you.

EDIT: Thrust table is added successfully. My previous XML file had an error. That is why OSG error was being shown.
Last edited by WittyOldman on Sat Mar 24, 2018 12:09 pm, edited 1 time in total.
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Re: Using thrust data in the propeller XML file

Postby Richard » Fri Mar 23, 2018 9:08 am

Can you post the thrust data table so we can see what it looks like and what parameters it takes.
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Re: Using thrust data in the propeller XML file

Postby daveculp » Fri Mar 23, 2018 3:27 pm

JSBSim uses the standard equation of thrust: Thrust = (K)(rho)(n)(n)(d)(d)(d)(d), where K is the Thrust Coefficient, rho is the air density, n is the rotational rate in rotations per second, and d is the diameter in feet. JSBSim uses the FPS (i.e. English) system of units internally.

You'll have to calculate "backwards" for each data point to get the Thrust Coefficient you need to build the table.
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Re: Using thrust data in the propeller XML file

Postby WittyOldman » Sat Mar 24, 2018 11:59 am

Richard wrote in Fri Mar 23, 2018 9:08 am:Can you post the thrust data table so we can see what it looks like and what parameters it takes.


It is a 3D table with fields altitude, throttle, and velocity.
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