Breakaway thrust
 

I am a student and am building an acf taxing emission model for congested airports taking into consideration the stop-go-stop-go condition . I need an equation for calculating breakaway thrust.

Every time an acf stops while taxing it has to burn up extra fuel to generate the breakaway thrust for moving again. This extra fuelburn has never been accounted for, in surface emission calculations. Now I need help to come up with an equation for breakaway thrust from which I will be calculate the excess fuelburn and resulting emissions.

I have read stuff posted by XPMorten. Is there a paper/documentation that I can read to know more about breakaway thrust, friction coefficient, drag etc related to aircrafts?

There's no equation. Some aircraft need some added thrust at some gross weights in various conmbinations of temperature, wind, and surface conditions. Some aircraft may even need it to continue taxi.

Are you going to try to compute the fuel burned using reverse to slow while taxiing?

This maybe "anti-green" and, God knows I am, but are you kidding?

GF

Ask Newton. N1, weight, rpm/flow, shouldn't be too hard. But don't tell the tax man. (or the taxi, man)

"Breakaway thrust" will vary with the aircraft type, the temperature of the grease in the wheel bearings, the tire inflation, the aircraft weight, the gradient of the taxiway or ramp/apron, wind, engine efficiency, taxiway surface, tire condition, temperature, and other such factors. Each is a variable, and each will affect aircraft operating under identical conditions, differently. Accordingly, you're not going to be able to put together a formula which accomplishes what you want.

Don't you worry.... he'll find an oversimplified formula to make his point, just like the oversimplified climate computer models used to "prove" "climate change".

Poor students... made to "live the lie" right from the start. :ugh:

CJ

Further to your equation, will include the pavement conditions. Ex: Good old solid conrete, in cold weather at JFk and you'll need little thrust to get things moving. On the other hand, the cheap crap that was used in Bangkok with the much higher tempuratures, and the airplane sinks like a leaky old boat. Hence, damb near need TOGA just to break into a slow taxi.

Thank you all