189
edits
JSBSim Engines: Difference between revisions
Jump to navigation
Jump to search
→Parameter definitions
| Line 42: | Line 42: | ||
=== Parameter definitions === | === Parameter definitions === | ||
{| class="prettytable" | {| class="prettytable" | ||
|minmp | |||
|this value is the nominal idle manifold pressure at sea-level without boost. Along with idlerpm, it determines the throttle response slope. | |||
|- | |||
|maxmp | |maxmp | ||
| | |this value is the nomial maximum manifold pressure at sea-level without boost. Along with maxrpm it determines the resistance of the aircrafts intake system. See air-intake-impedance-factor | ||
|- | |||
|displacement | |||
|this value is used to determine mass air and fuel flow which impacts engine power and cooling. | |||
|- | |||
|bore | |||
|cylinder bore is currently unused. | |||
|- | |||
|stroke | |||
|piston stroke is used to determine the mean piston speed. A longer stroke results in an engine that does not work as well at higher speeds. | |||
|- | |||
|cylinders | |||
|number of cylinders scales the cylinder head mass. | |||
|- | |||
|cylinder-head-mass | |||
|the nominal mass of a cylinder head. A larger value slows changes in engine temperature | |||
|- | |||
|compression-ratio | |||
|the compression ratio affects the change in volumetric effeciency with altitude. | |||
|- | |||
|sparkfaildrop | |||
|this is the percentage drop in horsepower for single magneto operation. | |||
|- | |||
|maxhp | |||
|this value is the nominal power the engine creates at maxrpm. It will determine bsfc if that tag is not input. It also determines the starter motor power. | |||
|- | |||
|static-friction | |||
|this value is the power required to turn an engine that is not running. Used to control and slow a windmilling propeller. | |||
|- | |||
|cycles | |||
|Designate a 2 or 4 stroke engine. Currently only the 4 stroke engine is supported. | |||
|- | |||
|idlerpm | |||
|this value affects the throttle fall off and the engine stops running if it is slowed below 80% of this value. The engine starts running when it reaches 80% of this value. | |||
|- | |||
|maxrpm | |||
|this value is used to calculate airbox resisance and bsfc. It also affects oil pressure amoung other things. | |||
|- | |||
|maxthrottle | |||
|Deprecated / unused | |||
|- | |||
|minthrottle | |||
|Deprecated / unused | |||
|- | |||
|numboostspeed | |||
|see notes | |||
|- | |||
|boostoverride | |||
|see notes | |||
|- | |||
|boostmanual | |||
|see notes | |||
|- | |||
|ratedboost[123] | |||
|see notes | |||
|- | |||
|ratedpower[123] | |||
|see notes | |||
|- | |||
|ratedrpm[123] | |||
|see notes | |||
|- | |||
|ratedaltitude[123] | |||
|see notes | |||
|- | |||
|takeoffboost | |||
|see notes | |||
|- | |||
|bsfc (Advanced) | |||
|Indicated Specific Fuel Consumption. The power produced per unit of fuel. Higher numbers give worse fuel economy. This number may need to be lowered slightly from actual BSFC numbers because some internal engine losses are modelled separately. | |||
|- | |- | ||
| | |volumetric-efficiency (Advanced) | ||
| | |the nominal volumetric efficiency of the engine. Boosted engines require values above 1. | ||
|- | |||
|air-intake-impedance-factor (Advanced) | |||
|this number is the pressure drop across the intake system. Increasing it reduces available manifold pressure. | |||
|- | |||
|ram-air-factor (Advanced) | |||
|this number creates a pressure increase with an increase in dynamic pressure (aircraft speed). | |||
|- | |||
|cooling-factor (Advanced) | |||
|this number models how effecient the aircraft cooling system is. | |||
|- | |- | ||
|} | |} | ||