Just like it would be rather foolish to redline your car engine on each and every single gearshift.

 

Are you not supposed to do that then?,, No wonder my garage bills are expensive!  :lol:

You'd have to search quite some time to find an operator in real life that goes for a max unrestricted climb. Just because the aircraft can do it, doesn't mean it's necessarily a good idea.

Just like it would be rather foolish to redline your car engine on each and every single gearshift.

 

That's how VNAV works though. It doesn't moderate throttle for speed, it uses pitch. The throttle spools  up to the derated N1, and the AP moderates climb rate to maintain speed. in the sim with all 3 models At a derated Clb-2,  with payload maxed, and fuel set to meet the Max landing weight at arrival, your still going to get a rather high climb rate if VNAV i used. I think we are all missing something here on how real operations  of a 777 actually is.

 

 

 

... The throttle spools up to the derated N1...

 

Exactly... There's no reason to squeeze every last bit of performance out of the airplane, every single time.

Do people realize that the high rate of climb is because the wing generates so much lift and has more thrust than it knows what to do with? At light weights it will climb like crazy, and it is NOT unrealistic. The wing has to produce that much lift to carry the aircraft at MTOM, and MTOM minus climb fuel at cruise altitude. Power to weight ratio rules. If you take an empty jet plus 20000 lbs of fuel, the weight is approx. 366600 lbs, making for a thrust-to-weight of 0.60:1.0, which is no slouch.

 

It wouldn't surprise me at all if the 777 was capable of 30000 ft in under 10 minutes from brakes release when light. I'd guess under 8 minutes (that's only an average of 3,750 ft/min).

 

Best regards,

Robin.

Ah, thank you Robin! Precisely why I posed the question initially!

 

Martin

I also seem to remember Warren (I think that is his name!) from the Project Opensky forums indicating that he at some stage had the privilege to fly a 747-400 simulator, fairly lightly loaded and he recorded that the 747, even on a good derate, WANTED to climb at something like 6000 feet per minute initially.

 

Then you also have to take into consideration that not ALL operators even allow for derates!   So now imagine that 777-200LR with an operator not allowing the derates and doing maybe a 3000nm trip...  Yeah, sounds hectic LOL!

 

Kind regards