Between 80 - 90% is what you're normally operating at. You could go higher is you follow the indicated parameters, watching EGT and also watching your airspeed indicator insuring you're not over stressing the air frame.
If that was the specific case for operating conditions on the Jumo 004B-4, then my original comment would apply to staying very near that range and not throttling down in order to slow down during combat conditions like a piston engine fighter would. (pulling sharp maneuvers - or using air breaks to bleed of speed when the situation merited it or especially when it was a matter of otherwise risking diving beyond the mach limit -or for allowing landing approaches with the throttle high enough to allow for a go-around without waiting for the engines to spool back up)
Again, I think brakes aerodynamically designed and placed to help facilitate critical mach pull-out would be ideal, and was under the impression that the P-80's belly brake did allow this in addition to slowing the plane down.
stoichiometric? In my experience that term is normally associated with recips as the mixture can be controlled. An adverse stoichiometric fuel mixture in a turbine engine is something beyond operator control, and could tell you that most pilots don't even know what that is!
Turbine engines are normally designed to maintain a near-stoichoimetric fuel/air mixture within the flame tubes within cans or burners in annular combustion chambers (so-called 'combustors' in most turbine engine terminology I've seen, or at least the British references) with the hot combustion products then combining with the majority of remaining compressed air before entering the turbine section. Throttling up too quickly on the 004B would allow over-fueling of the engine and introducing a rich mixture to the flame tubes, partial combustion and further combustion of the products when introduced to that excess air stream, thus resulting in a higher turbine inlet temberature (or a spike in temperature until the compressor could spool up to the proper mass flow for the fuel being injected)
In any case the net effect (from the perspective of the turbine inlet) is the engine running less-lean and thus runs hot. (jet engines normally running extremely lean with mostly air passing through the system and a limited amount of hot combustion products adding the energy to drive the turbine)
I say 'less lean' rather than 'rich' because rich implies more fuel than there is air to oxidize it, which is not the case.
At what point would divebrakes/airbrakes be necessary in the execution of this attack? Deploying divebrakes/airbrakes in the middle of a bomber stream would achieve two results:
1 - it would allow more exposure for the defensive gunners to put a round in your engine or other vital portion of the aircraft
2 - it would allow the escorts to gain closer ground to intercept you.
Brakes are for when things go wrong or might go wrong, not for use during an attack, and they'd apply to similar cases where they'd be useful on the Meteor or P-80 (or YP-80) BEFORE the post-war models with better thrust to weight ratios. The P-59 could have done with brakes too given it tended to have such good gliding ability that it would 'float' on landing approaches and was hard to get it to set down. (low wing loading and relatively low drag at low speeds -it had problems with transonic drag at moderate speeds mostly due to the engine nacelle design, I believe)
So:
- avoiding diving too fast or assisting in recovering from critical mach dives
- holding down maximum speed on landing approaches (very similar context to controlled dives) while keeping throttles up to allow rapid acceleration for a go-around if needed.
- least desirable case: fighter on your tail or other situation where the best (desperate) option is to force an overshoot to provide enough time to dive and accelerate away before they can make another pass.
The context isn't that much different from post-war examples, but certainly more dramatic in different performance envelopes. The F-86 vs Mig 15 might be one of the closer cases given the Saber diving better and having better top speed (and higher critical mach and better ability to cope with supersonic speeds) while the MiG had lower wing loading and better thrust to weight ratio for better climb, turn, and acceleration. (also better speed control through throttle allone, less inertia/mass and more control over thrust -you can't control your weight, so that gravity 'thrust' in dives on the F-86 is going to he high regardless of throttle settings) You wouldn't want to use the brakes unless you had to, but when you DID need them, you'd sure be glad they were there.
Also remember that even though the F-86 COULD recover from a supersonic dive, it also needed a good amount of altitude to do so and while I don't believe the brake was safe to operate at such speeds, it WAS useful as a preventive measure.