Targetware: Flight Model Development

Targetware ACM File Guide

PART REFERENCE: Prop

The following entries are unique to the 'prop' type.

bore = diameter of piston head in millimeters
stroke = length of stroke in millimeters
cylinders = number of cylinders
cycle = 2 and 4 cycle engines are supported
compression = compression ratio of engine
fuel_type = octane, methanol, nitromethane

Different fuels have different ideal mixture ratios, affecting fuel consumption

throttle_type = regulated, normal, none

The purpose of a manifold pressure regulator is to prevent over-boosting of the engine by limiting how much air goes into the cylinders regardless of the throttle setting that the pilot has chosen.  Without a regulator, it may be very easy to over-boost the engine at low altitudes with only partial throttle.

throttle_rate = inverse of the time to advance or retard the throttle completely
throttle_idle = number between 0 and 1 (0.05 works well), representing fraction of open throttle
turbocharger = set to 1 if turbocharging is available, otherwise set to 0
liquid_cooled = set to 1 if liquid cooled engine, set to 0 if air cooled
auto_blower = set to 1 if supercharger changes gears automatically, 0 for manual control
max_rpm = upper limit of propeller governor, for constant speed props
min_rpm = lower limit of propeller governor, for constant speed props
gear_ratio = the ratio of propeller rpm to crankshaft rpm
military_mp = manifold pressure at military power setting, in atmospheres
combat_dry_mp = manifold pressure for combat power setting, in atmospheres
combat_wet_mp = manifold pressure when anti-detonant injection (ADI) is in use, in atmospheres
num_crit_alt = the number of gears or speeds of the supercharger
crit_power = power at each critical altitude, separated by a comma, in kilowatts
crit_alt = critical altitude for each speed of the supercharger (no ram) in meters, separated by a comma

diameter = meters
prop_mass = kilograms

The propeller mass is important for engine response characteristics.

solidity = fraction of the propeller disc that is solid
rotation = clockwise or counterclockwise
pitch_type = fixed, variable or constant

A fixed pitch prop is only efficient at one speed/rpm combination, usually cruising, since that's where a plane spends most of it's flight.  Takeoff and climb performance usually suffer.   A variable pitch prop allows the propeller to keep it's efficiency over a greater range of speeds, but the pilot must manually set the pitch to the proper setting, which in turn will affect rpm and power output.  The constant speed propeller allows the power output and rpms to remain constant while automatically adjusting the propellers pitch for best efficiency, greatly reducing the pilot's workload.

min_pitch = minimum geometric pitch angle at 0.75 radius
max_pitch = maximum geometric pitch angle at 0.75 radius
pitch_rate = the rate, in deg/s, that the governor can adjust the blade pitch

The minimum pitch angle should be set low enough that full power can be obtained for takeoff.  The maximum pitch angle should be set so that the propeller does not hit it's limit before the maximum speed of the aircraft is obtained.  Once the pitch hits it's maximum limit, a continued increase in airspeed will force the propeller to overspeed and permanent damage may occur.

featherable = 1 if the prop can be feathered, otherwise 0
unfeatherable = 1 if the prop can be unfeathered, otherwise 0

Feathering a propeller sets the blade angle to 90 degrees, minimizing the drag.

max_alpha = see airfoil
min_alpha = see airfoil
zero_alpha = see airfoil
critical_mach = see airfoil
 

fire = path to particle file
leak = path to particle file
start_sound = path to sound file
sound = path to sound file
stop_sound = path to sound file
parent = name of parent part (engine), whereby if parent departs the airframe, so does this child part.

orientation = x, y, z