Input and Output Units

You can enter the values of input parameters in any available units, freely mixing Metric (SI) and U.S. Customary systems. The program automatically converts all entered values to the Metric system, which is standard internal representation of both input parameters and results of calculation.

The following conversion factors are used to convert values in non-SI units to values in SI units:

Name	Value	Description
CONST_ATM	101325.0	Conversion factor from atm to Pa
CONST_AT	98066.5	Conversion factor from at (technical atmosphere) to Pa
CONST_BAR	100000.0	Conversion factor from bar to Pa
CONST_PSI	6894.75729316836	Conversion factor from psi (pound-force per square inch) to Pa
CONST_T0	298.15 K	Temperature 25 C
CONST_R0	8.314472 J/(mol·K)	Universal Gas Constant
CONST_G	9.80665 m/s2
CONST_POUND	0.45359237	Conversion factor from lbm (pound mass) to kg
CONST_POUND_FORCE	(CONST_POUND*CONST_G)	Conversion factor from lbf (pound-force) to N (newton)
CONST_FOOT	0.3048	Conversion factor from international foot to m
CONST_INCH	0.0254	Conversion factor from inch to m
CONST_MILE	(5280.0*CONST_FOOT)	Conversion factor from international mile to m
CONST_LBM_FOOT3	(CONST_POUND/CONST_FOOT3)	Conversion factor from "lbm/ft3" to "kg/m3
CONST_LBM_INCH3	(CONST_POUND/CONST_INCH3)	Conversion factor from "lbm/inch3" to "kg/m3"
CONST_MASS_FLUX	(CONST_POUND/CONST_FOOT2)	Conversion factor from "lbm/(ft2·s)" to "kg/(m2·s)"
CONST_LBM_MOLE	(1000.*CONST_LBM)	Conversion factor from lb-mole to mole
CONST_BTU	1055.05585262	Conversion factor from Btu to J
CONST_CAL	4.1868	Conversion factor from calorie to J
CONST_BTU_LBM	(CONST_BTU/CONST_LBM)	Conversion factor from Btu/lbm to J/kg
CONST_BTU_LBM_MOLE	(CONST_BTU/CONST_LBM_MOLE)	Conversion factor from Btu/lb-mol to J/mol
CONST_BTU_LBM_R	(1000.*CONST_CAL)	Conversion factor from Btu/(lbm·R) to J/(kg·K)
CONST_BTU_LBM_F	CONST_BTU_LBM_R	Conversion factor from Btu/(lbm·F) to J/(kg·K)
CONST_BTU_LBM_MOLE_R	CONST_BTU_LBM_R	Conversion factor from Btu/(lb-mol·R) to J/(mol·K)

The Metric system is also used by default to display the results of calculation. You can change it to U.S. Customary system, using dialog window Preferences.

References:

• SP-811. NIST Guide for the Use of the International System of Units (SI). B.8 Factors for Units Listed Alphabetically
• Glossary of terms and table of conversion factors used in design of chemical propulsion systems. NASA SP-8126. 1979.
• George P. Sutton, Oscar Biblarz. Rocket Propulsion Elements, 7th Edition (pp.727-729).
• NASA-STD-3000. Man-Systems Integration Standards. Volume II. Appendix E - Units of Measure and Conversion Factors

Last modified: May 14, 2011