SurClaro Flight Simulator Resources

Posted: Thu Jul 26, 2007 11:17 pm Post subject: Limited Speed at High Altitides

Hey,
when i fly larger jets (Like 757's etc.) at higher altitudes their max speeds get lower. E.G. When i fly a boeing 737 up to around 32,000 ft, the maximum speed before the overspeed banner starts ticking, is only 200 or so knotts. The speed below around 27,000 ft is fine at around 350knots, but as you climb the red bar that shows the maximum allowed speed gets lower and lower.
can you help me?
thanks
kieran Confused

Posted: Thu Jul 26, 2007 11:46 pm Post subject:

its normal. Its because at higher altitudes the air gets thinner. Im sure someone with more knowledge and isnt as tired will be able to tell you about it. But after FL290 (i think?) you switch over to mach. Look at the groundspeed as youl climb. You will notice it increase as you go higher as ther is less resistance.

Im sure someone else will be able to explain better than i could, but it is perfectly normal and there isnt a problem with your aircraft.

(I have been there before and thought the same thing)

Posted: Thu Jul 26, 2007 11:48 pm Post subject:

Hiya again...try this...go to SETTINGS/REALISM AND WEATHER/INSTRUMENTS AND LIGHTS....and make sure the little circle that says 'Display true air speed' is checked....geez, I hope I'm right on this one, I had the same question when my hypersonic jet always seemed to be on valiums at high altitudes. Best of luck. Wink

Posted: Fri Jul 27, 2007 12:12 am Post subject:

If you want to be realistic, leave it at indicated airspeed. If you don't want to be realistic, and want the airspeed indicator to display the speed you're traveling at in relation to the ground, do what hark said.

The lower speed readings are normal. Air is thinner at higher altitudes, therefore the indicator displays a lower speed. But, check your GPS on the other hand, and you'll discover that even though indicated is lower, most likely you'd be traveling faster than you would in relation to the ground if you flew at a low altitude.

Posted: Fri Jul 27, 2007 12:13 pm Post subject:

Thanx guys thats all great and fixed the problem
CHEERS!

Laughing

Posted: Fri Jul 27, 2007 1:10 pm Post subject: a no-no

Nw you have true A/S. Are you using "True North" also? Might as well have everthing TRUE.

I have yet to see ANY commercial birds AND ABSOLUTELY NEVER EVEN HEARD OF A MIL-JET using TRUE Air Speed.

Why?

All gauges are made for INDICATED AIRSPEED, (barometrically inclined)

All NAV Charts are made to travel at speeds relevant to INDICATED AIRSPEED. NEVER EVER TRUE Air Speed.

HEY, they figured that out for us. CALLED it GS= GroundSquirrel, I mean ground speed. Look in the ADI window of the PDF.

With true a/s, you will never make a perfect landing to spec. DUE TO all numbers/prameters are in Indicated Airsped.

ETC., ETC., ETC.

READ up on it's TRUE use.

Tomcatdriver

Posted: Fri Jul 27, 2007 9:47 pm Post subject:

This is an excellent question and you received some great answers. I sounds like you are the type of person who likes to dig deeper down into the "Hows and Whys".

Since this is a "technical" type of question that involves a technical answer, I wish to make one suggestion based upon my own personal experience.

Use your library card and check out a few books. I have spent many hours at the local library doing research about Aviation.

Here are two books that I have seen listed recently on the internet. I have the first book and highly recommend it:

http://www.bruceair.com/

http://www.wiley.com/WileyCDA/WileyTitle/productCd-0764588222,descCd-DOWNLOAD.html

PS: I just know that GroundSquirrel is going to reply to my response. Both of us encourage you'all to use your library card. You'all should know how to read before you'all learn how to fly.

GS will probably reply, "SKIP, YOU ARE ASKING THEM TO READ".

Posted: Sat Jul 28, 2007 6:50 am Post subject:

Make that 3 there Skipper. I believe in the library, and have posted alot to go there for info.

It's a free resource, if you want to know or learn about anything and everything.

RD

Posted: Sat Jul 28, 2007 7:08 am Post subject: 4

4...i am a terrible typist, so PLease do what GS, SKIP & RD, said,

READ & PLEASeE don't beat this old dog to death