[FEATURE] Improved Jet Engine fuel Burn Characteristics

[decaff42]

Feature Description
YSFlight & YSCE fuel consumption is currently only a function of throttle position, which is not realistic in most jet aircraft scenarios.

How would this function work?
Ideally the fuel consumption would be based on altitude.

Why is this feature important?
Provides better realism and allows for more realistic penalties of flying low-level in combat profiles.

Any examples as to how this feature would work?
This could be done in several ways. I think #1 would be a good compromise for all types of engines for now.

1. FUELMILIT and FUELABRN would define sea-level performance. The value would linearly reduce from sea level to 1/3 at REFACRUS and maintain 1/3 for all higher altitudes. This is approximately what was shown experimentally by NASA in a Global 5000
2. The jet-engine efficiency factor would be applied to burn rate to simulate the function of altitude.

[NodokaHanamura]

Sorry for the delay - Went ahead and assigned peeps to it.