Hi all,I have started to learn to fly Alphasim's awesome U-2S. I have been trying to fly a high-altitude airway flight at FL700, from Nellis to Beale AFB. Apparently thinking that the U-2 is some kind of commercial airliner, ATC will direct me into what I call a "stepped climb"--incrementally bumping me up to my cruising altitude ("Climb to FL180"..."Climb to FL330"..."Climb to FL600"...etc). As per the instruction manual included with the aircraft package, I try to keep my speed as close to 100 KIAS as possible--even if this means cruising at idle throttle in between ATC-ordered altitude changes. Realistically, I cannot fly above FL350 or so. Above around 40,000 feet, the aircraft stalls--even with autopilot on!Is this accurate? Are real U-2 pilots allowed an "unrestricted climb" up to 70k feet, or do they also have to climb in increments? The Alphasim manual doesn't cover cruising below 56,000 feet. Is there any way I can accurately fly the thing up to FL700 without the aircraft stalling?

Hi all,I have started to learn to fly Alphasim's awesome U-2S. I have been trying to fly a high-altitude airway flight at FL700, from Nellis to Beale AFB. Apparently thinking that the U-2 is some kind of commercial airliner, ATC will direct me into what I call a "stepped climb"--incrementally bumping me up to my cruising altitude ("Climb to FL180"..."Climb to FL330"..."Climb to FL600"...etc). As per the instruction manual included with the aircraft package, I try to keep my speed as close to 100 KIAS as possible--even if this means cruising at idle throttle in between ATC-ordered altitude changes. Realistically, I cannot fly above FL350 or so. Above around 40,000 feet, the aircraft stalls--even with autopilot on!Is this accurate? Are real U-2 pilots allowed an "unrestricted climb" up to 70k feet, or do they also have to climb in increments? The Alphasim manual doesn't cover cruising below 56,000 feet. Is there any way I can accurately fly the thing up to FL700 without the aircraft stalling?

When you're using the default ATC for an IFR flight, it will always impose random climb limits ("Climb to FL210 etc.) but usually just before you reach that altitude it clears you to the next one until you are finally cleared to your filed flight level. It's not exactly "real world" but it's not unusual for ATC to give incremental altitude clearances when flying in the real world... If it was operating within controlled air space, the U2 would have to operate within the same ATC limits as other aircraft.The inability of the U2 flight model to handle very high altitudes doesn't surprise me - I have run up against the same kind of altitude limitations with other high performance FS aircraft that should have been able to easily operate above FL400 but couldn't. I can't help you in "tweaking" the flight model but perhaps someone reading this could make some suggestions. The likely problem is that improving very high altitude performance will probably result in unrealistic behavior at the lower altitudes, but there are often ways to work some FS magic if you have the expertise... Good luck with it...Ian

Thanks for the advice, but I was asking more for advice on how to fly the aircraft. Very interesting information though!

Some help would be greatly appreciated :(

Anyone?

I seem to remember from reading age-old posts that there is an altitude limit in FS9 such that aircraft such as yours, X-15, F104 etc. cannot reach their rated ceiling.Perhaps you should try a search?