Machinbird
Well lets get started. Let's examine these facts.
My favorable experience with jet engines at high AOA does not include experience with Fan type wing mounted engines. Why are Fan type engines so much more finicky (if they indeed are)? And as always, others are welcome to join in.
Since the J79 engine (an augmented turbojet), nearly all the newer military fighter engines are actually augmented turbofan engines. A major difference, of course, is the diameter of the fan. The core of the CFM56 engine is basically the same as the core of the F101/F110 engines. There are some key differences that are addressed in different manners. On military fighter engines, the flight envelope is more extensive than a commercial turbofan flight envelope and therefore must handle more severe conditions, more or less whatever the pilot wants the fighter to do. Engine controls have advanced providing more operating stability across the flight envelope. For both commercial and fighter engines, the control systems are designed to regulate engine power and efficiency by manipulating available variables as a function of sensed parameters. The manipulated variables are varied to schedule or set the controlled variables. The controlled variables and sensed parameters are selected to meet system requirements.
All turbofan engines have unique component requirements to maximize efficiency and ensure stall free operation. For example, fighter engines require a fan IGV (inlet guide vane) that can be varied for inlet distortion control. In the CF6-80E engine, the high pressure compressor inlet is "supercharged" by the low pressure compressor that consists of the hub section of the big fan and 5 airfoil stages.To provide adequate stall margin, a VBV (variable bleed valve) system is incorporated into the fan frame, which are actually hinged doors. The doors are open at idle to discharge air into the fan flowpath (bypass), but at high power the doors are closed to improve engine performance.
So, controlled variables include fan speed (N1), core speed (N2), HPT blade temperature (T4B) on fighter engines, exhaust gas temperature (EGT), compressor discharge pressure (PS3), augmenter fuel flow (WFR) on fighter engines, fan discharge Mach number (M25, ∆ P/P) on fighter engines, and fan and compressor variable geometry (IGV's, VSV's and VBV's).
The manipulated variables which are modulated directly by the control system to maintain control of the above controlled variables are as follows:
1. Main fuel flow (WFM)
2. Augmenter fuel flow (WFR)
3. Exhaust nozzle area (A8)
4. Compressor variable stator vanes (VSV's)
5. Fan variable inlet guide vanes (IGV's)
6. Variable bleed valves (VBV's)
7. Thrust reverser
This is only a short listing where stall prevention is prime, but demonstrates quite a few similarities and some differences in today's modern turbofan engines, commercial or military.
In my opinion, big turbofan engines today are no more or no less "finicky" than their modern day fighter engine counterparts. I should add one other comment: Most of this technology evolved from the military J79 engine, the difference being the J79 produced 17,000 pounds of thrust and the F110-129 produces 30,000 pounds of thrust!
TD