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- GalaxyFlyer
- Posts: 12406
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Re: maximum speed
What do you mean--indicated, Mach, true airspeed? In what flight regime? By what type?
Re: maximum speed
When asked the way it was asked, the OP is almost certainly asking about ground speed.
Re: maximum speed
There are too many variables to answer.
Civil/military/experimental/all?
Any altitude or restricted?
Do we include vertical launched objects such as rockets?
What powerplant? Any, rocket, jet, piston?
Judging whether GS/TAS/IAS and what units is the least we should worry about.
Cheers,
Adam
Civil/military/experimental/all?
Any altitude or restricted?
Do we include vertical launched objects such as rockets?
What powerplant? Any, rocket, jet, piston?
Judging whether GS/TAS/IAS and what units is the least we should worry about.
Cheers,
Adam
Re: maximum speed
Fedric1234 wrote:What is the maximum speed reached during the flight?
Highest speed is reached during the cruise phase, the exact amount of which depend mainly on the aircraft type and how much you work the engines. A 737 Classic, for example, typically cruises at Mach 0,75. An A320 usually does around .78. A 747 is around .85 and a Gulfstream 650 can make it to .92.
In other words 'how long is a piece of string'.
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- maortega15
- Posts: 362
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Re: maximum speed
B777LRF wrote:In other words 'how long is a piece of string'.
Depends on how you cut it.
Re: maximum speed
maortega15 wrote:B777LRF wrote:In other words 'how long is a piece of string'.
Depends on how you cut it.
Twice the length from it's centre to one end.
Works every time 
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- Fedric1234
- Posts: 5
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Re: maximum speed
Gloom thanks your reply.
1) everyone
2) Any altitude
3) no
4) jet
1) everyone
2) Any altitude
3) no
4) jet
Re: maximum speed
I would imagine the fastest true airspeed of an aircraft would be at the altitude where you transition from indicated airspeed to indicated Mach.
For example for a CRJ-700 the transition is at FL316 indicating 335kts and M0.85 you get a true airspeed of around 495kts
For a 320 the altitude is FL246 at 350kts and M0.82.
That’s if you ride the edge of the envelope.
When you climb higher than the altitude of the speed/Mach transition, your Mach number remains the same but your true airspeed will decrease. Using the CRJ-700 example flying at M0.83 at FL360 will result in a true airspeed of around 465-470kts
The winds then affect the actual ground speed achieved by the aircraft.
For example for a CRJ-700 the transition is at FL316 indicating 335kts and M0.85 you get a true airspeed of around 495kts
For a 320 the altitude is FL246 at 350kts and M0.82.
That’s if you ride the edge of the envelope.
When you climb higher than the altitude of the speed/Mach transition, your Mach number remains the same but your true airspeed will decrease. Using the CRJ-700 example flying at M0.83 at FL360 will result in a true airspeed of around 465-470kts
The winds then affect the actual ground speed achieved by the aircraft.
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- SheikhDjibouti
- Posts: 2348
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Re: maximum speed
Fedric1234 wrote:Gloom thanks your reply.
1) everyone
2) Any altitude
3) no
4) jet
I realise you are new to these boards, as indeed I am too, so maybe you will permit me to help clarify your question/comment.
Gloom wrote / you answered...
There are too many variables to answer.
Civil/military/experimental/all? "everyone"
Any altitude or restricted? "Any altitude"
Do we include vertical launched objects such as rockets? "no"
What powerplant? Any, rocket, jet, piston? "jet"
Unfortunately this still leaves us asking more questions.
Are you asking a simple question, i.e. what is the fastest aircraft ever? The main candidate would be the SR-71
Or are you asking something more complicated, such as the fastest speed that a particular type of aircraft might achieve? (typically in level flight)
Whilst it is great to open a discussion here on a.net, I also find that Wikipedia is usually a good resource
https://en.wikipedia.org/wiki/Flight_airspeed_record
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- Fedric1234
- Posts: 5
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Re: maximum speed
Thank you for your reply, I am new to these boards.
Re: maximum speed
Fedric1234 wrote:Thank you for your reply, I am new to these boards.
Start here: https://www.nasa.gov/sites/default/file ... le_k-4.pdf
Re: maximum speed
Fedric1234 wrote:Gloom thanks your reply.
1) everyone
2) Any altitude
3) no
4) jet
Mach speeds from 0.78-0.92 would pretty much cover all commercial jets in currently in operation. At 35,000ft this would equate to 515mph-610mph. Most modern widebody jets (like the 787 or a350) cruise at mach 0.85, which is 564mph at 35,000ft.
However, in terms of how fast you're moving over the ground (ground speed) it varies wildly due to wind. Aircraft can fly into 150mph headwinds, reducing their ground speed by that amount, or fly with a 150mph tailwind, increasing the ground speed by that amount. Incidentally, I was on a 747-400 from the US to the UK and our tailwinds were so strong that the ground speed on the moving map read 750mph.
To give you anything more detailed than that you're going to have to be more clear of what you need.
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- Starlionblue
- Posts: 21730
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Re: maximum speed
As hinted above, one of the issues with answering the question is that an apparently simple concept such as "speed" is not that simple in an airliner. We have indicated airspeed, calibrated airspeed, equivalent airspeed true air speed, Mach and ground speed. The relations between them are not constant. They vary due to density, compressibility effects and wind.
For example in the cruise we might be at Mach 0.82 with a ground speed of 480 but the indicated airspeed is only 240, while 20000 feet lower indicated airspeed might be 310 with a lower ground speed and Mach 0.6.
You can get lots of fun info here, including the maths. https://en.wikipedia.org/wiki/Airspeed
On the 330 normal cruise is at Mach 0.82. On the 350 it is M0.85. Ground speed with nil wind is around 480 knots. However given wind effects ground speeds anywhere in the 350-600 range aren't unusual
For example in the cruise we might be at Mach 0.82 with a ground speed of 480 but the indicated airspeed is only 240, while 20000 feet lower indicated airspeed might be 310 with a lower ground speed and Mach 0.6.
You can get lots of fun info here, including the maths. https://en.wikipedia.org/wiki/Airspeed
On the 330 normal cruise is at Mach 0.82. On the 350 it is M0.85. Ground speed with nil wind is around 480 knots. However given wind effects ground speeds anywhere in the 350-600 range aren't unusual
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