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overspeeds at cruising altitude (Read 867 times)

Feb 19^th, 2004 at 9:07pm

BeukStylez03 Offline
Colonel

Posts: 137

Ok, I have this problem with every single aircraft I use. I finally get to her level cruise altitude...for example, I'm using a Cessna Citation II and she cruises at 35,000 feet at a max speed of about 420 mph...why is it that I can't get her even close to that without hearing my controls go crazy and seeing "overspeed" in the corner of the screen? I just don't get it.

help?

-Steve Butka

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Reply #1 - Feb 20^th, 2004 at 7:00am

Ivan Offline
Colonel
No, I'm NOT Russian, I
only like Russian aircraft
The netherlands

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Use IAS instead of TAS

Russian planes: IL-76 (all standard length ones), Tu-154 and Il-62, Tu-134 and An-24RV&&&&AI flightplans and repaints can be found here

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Reply #2 - Feb 20^th, 2004 at 12:32pm

BeukStylez03 Offline
Colonel

Posts: 137

Quote:

Use IAS instead of TAS

I have the IAS button engaged on the autopilot. ???

-Steve Butka

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Reply #3 - Feb 24^th, 2004 at 1:58am

congo Offline
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Make BIOS your Friend
Australia

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Use TAS.

Indicated airspeed shows as much slower than the True airspeed at altitude, because the air is not as dense up there, fewer air molecules are striking the pitot tube, ie. lower air pressure = lower reading on the ASI.

While cruising, change briefly back to True Airspeed for a look.

Structural limits on the aircraft are more closely related to Indicated Airspeed, not true airspeed, hence we retain the use of IAS, it provides us with an easy reference so we don't stress aircraft.

If you are setting the Indicated Airspeed hold to 500kts at altitude, then you are trying for supersonic, that's why you are getting speed warnings.

Mainboard: Asus P5K-Premium, CPU=Intel E6850 @ x8x450fsb 3.6ghz, RAM: 4gb PC8500 Team Dark, Video: NV8800GT, HDD: 2x1Tb Samsung F3 RAID-0 + 1Tb F3, PSU: Antec 550 Basiq, OS: Win7x64, Display: 24" WS LCD

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Reply #4 - Feb 25^th, 2004 at 11:30am

OTTOL Offline
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Fintas, Kuwait (OKBK)

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Posts: 918

Use MACH!

Above FL310 you should be using Mach, for the purposes of ATC querries and Autopilot settings. At this Altitude, IAS AND TAS are for planning and reference ONLY! You may see magazines and Jane's books and manufacturer brochures expressing cruise speed in Knots(or MPH(especially in the case of the manufacturer! ) This is mostly done for a matter of reference(it's easier for a non-pilot or a pilot for that matter to relate speed when expressed in knots. IE: at FL350>Mach.80=230KIAS=450TAS Which one makes the most sense to you? The last one does for me(the speed at which the A/C is actually travelling through the air). Nonetheless, Mach is still used for Autopilot reference and ATC planning.

.....so I loaded up the plane and moved to Middle-EEEE..........OIL..that is......

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