Confused about cruise speed
Printed From: Just Flight Forum
Category: Just Flight Products
Forum Name: DC-8 Jetliner Series 10 through 70
Forum Description: Discussion area for the Just Flight DC-8
URL: http://forum.justflight.com/forum_posts.asp?TID=31411
Printed Date: 16 Apr 2024 at 7:59pm
Topic: Confused about cruise speed
Posted By: flyforever
Subject: Confused about cruise speed
Date Posted: 17 Apr 2017 at 1:29am
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The dc8 specs indicate a cruise speed of 480kts. How does one test this. I get overspeed conditions when the IAS reaches 340 kts. As I bring the aircraft to a higher altitude, not much changes. What's the secret? tony ------------- FV |
Replies:
Posted By: Mustang1977
Date Posted: 17 Apr 2017 at 7:38am
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Yo, The 480 kts is the GS - Ground Speed. The 340 is correct, as you can see the values in the aircraft.cfg (here the 32): cruise_speed=460.0 max_indicated_speed=370.000000 max_mach=0.88 The max indicated speed can only be reached in a specific height - this you have to find out. This varied from airplane to airplane. Generally between 25.000 - 28.000 ft for Jetliners. But attention: The GS can easily distorted with wind. So, for best Testresults you have to disable a possible Weatherengine and select the neutral weathermodel. |
Posted By: Hangar200
Date Posted: 30 Apr 2017 at 5:17pm
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Actually, a DC-8 once went super-sonic. http://www.airspacemag.com/history-of-flight/i-was-there-when-the-dc-8-went-supersonic-27846699/" rel="nofollow - http://www.airspacemag.com/history-of-flight/i-was-there-when-the-dc-8-went-supersonic-27846699/ …I don't suppose that part of the flight envelope was written into JustFlight's version.  ------------- R/ Hangar 200 |
Posted By: Mike70
Date Posted: 30 Aug 2017 at 12:52am
| Use 300 knots Indicated below FL310; 0.80 Indicated Mach above FL310 for a decent cruise profile for mid-long range |