by JerryH » Tue Sep 28, 2004 5:45 pm
Rafiki,
There are no simple answers to your question. Let me try to explain what I mean by that.
The best way to increase the ceiling altitude from 30,000 to 45,000 is to redesign the aircraft with a much longer wing span, lower gross weight and a substantial increase in the thrust of the engines.
We can fake this by changing some numbers in the aircraft.cfg file, but there will usually be unintended consequences. Under the category of (flight_tuning), put in a value for cruise_lift_scalar of 2.0 or higher. In the category of (TurbineEngineData), double the value for static_thrust. These are just starting points.
Now, fly the CRJ and see how much the ceiling and speed have improved. After that, try an approach and landing at your favorite airport. Chances are that the above changes will cause a nose-down attitude during approach and possibly a higher setting for idle thrust. In other words, we've improved one problem area and messed up another phase of flight. In short, that is the risk of "tweaking" the flight dynamics. I know; I've messed them up more than once.
Back to the original problem. My search for CRJ-200 specs tells me that the ceiling altitude is 41,000 feet and the high-speed cruise is Mach 0.81. I'm sure the ceiling spec is for the aircraft at a low-fuel condition. If you're trying to fly to a very high altitude after a max gross weight takeoff, it just might not be possible.
Let me know if I've interpreted your question correctly, and sorry if the above sounds like a lecture. All of us want to make our favorite aircraft fly "right". I'm just trying to point out that it usually isn't as easy as tweaking a few numbers.
Regards,
JerryH
