How you guys doing using the speed select ? I'm trying to go by the book and climb out  using 225 knots  to 29,000 ft. then Mach .60 from there to 43000 where i like to go to , but it doesn't seem to hold for me so i don't know if i'm doing some thing wrong. She does go up like  a jack rabbit , the real world test says it will go to 43,000 ft in 20 min. and it sure does that well.Ray sent me an awesome set of  charts which are so complete a little more and it would tell how to change a flat tire . I'm having trouble with charts for distance load  load and time - yesterday i ran out of fuel on desend and was way over my arrival time according to the charts so  i'm fiddling with that at now --600 mi. trip @ 43,000ft.  says 1:30hr ETA  and fuel 1,637 pounds  for fuel, so i'll see what happens-- i got 50 knots on the tail,  grounding 490 knts - 88%N1 and .75Mach  . Man , Rays charts  has are unreal , gonna be interesting   to his his Avsim review. 

You may have run out of fuel because your airspeed and Rate of Climb were both too fast.

 

Some of the performance statistics quoted in the most dependable sources may have been accomplished with a minimum crew, no passengers or cargo and a quick up to max. altitude, then reduce throttle to almost zero for a descent and landing at the base airfield.

 

To conserve fuel on a normal flight you might try an initial climb at 180kts IAS at 1800ft/minute rate of climb, when you reach 18,000ft change to standard barometric pressure of 29.92" and increase speed to 200kts IAS and a rate of climb to 2,000ft/minute.

 

You won't make 43,000ft in 20 minutes using the above method but you might avoid a deadstick landing.