Help Reading F-106 Delta Dart Performance Charts Contained in the F-106 manual

[hawker111]

Hello,

 

I have been studying a couple of charts from the F-106 Delta Dart flight manual, and the speeds shown are in mach.

 

Since mach changes at different altitudes, I was curious to know if the charts in the manuals showing mach numbers use static mach numbers (1Mach = 661.47knots).

 

Or, do the mach numbers on the charts need to be converted to knots with an aviation calculator such as the one on this page:

 

http://www.hochwarth.com/misc/AviationCalculator.html

 

If you would like to see the charts in the F-106 manual, you can download the manual here:

 

http://www.f-106deltadart.com/manuals_documents.htm

 

The manual I downloaded is:

 

T.O. 1F-106A-1 (1969, rev.1972)

 

Please take a look at pages 6-8 to 6-18.

 

I appreciate the help very much!

[Fubar512]

Mach 1.0 is Mach 1.0, regardless of altitude. The airspeed indicator always reads indicated airspeed, which varies with altitude. Only certain aircraft types (the F-4 Phantom being one of them), had a ground-speed readout in addition to the airspeed indicator.

[hawker111]

Thank you, Sir.

 

The reason why I asked is because I read this yesterday:

 

"The speed of sound (otherwise known as Mach 1) varies with temperature. At sea level on a “standard day,” the temperature is 59°F, and Mach 1 is approximately 761 mph. As the altitude increases, the temperature and speed of sound both decrease until about 36,000 feet, after which the temperature remains steady until about 60,000 feet. Within that 36,000–60,000 foot range, Mach 1 is about 661 mph. Because of the variation, it is possible for an airplane flying supersonic at high altitude to be slower than a subsonic flight at sea level."

 

But according to the USAF flight manuals, when a chart says . . .

 

MACH .2 at 5,000 ft.

and says

MACH 2.0 at 35,000 ft.

 

. . . what I need do to get the speed in "true airspeed knots" is to . . .

 

multiply .2 x 661.47 = 132 knots

multiply 2.0 x 661.47 = 1,323 knots

 

?

 

I wasn't sure if I should multiply the mach numbers by different numbers because each mach number is for a different altitude.

[Fubar512]

That is correct, it is temperature that causes a variation in Mach, not pressure.  I found it a bit hard to understand at first, until I saw this chart.  I hope it helps you, as well:

 

 

 

 

 

[hawker111]

Therefore, I can't simply use this formula to convert the mach numbers on the F-106 charts to true airspeed knots?

 

multiply .2 (which is at 5,000 ft) x 661.47 = 132 knots

 

multiply 2.0 (which is at 35,000 ft) x 661.47 = 1,323 knots

[hawker111]

So I will have to use this conversion tool:

 

http://www.hochwarth.com/misc/AviationCalculator.html

 

according to this tool:

 

mach .2 at 5,000ft = 130 knots (true airspeed)

mach 2.0 at 35,000ft = 1,153 knots (true airspeed)

 

But this tool is not calculating the numbers correctly.

[hawker111]

I'm sorry, I think the tool is calculating correctly!

 

Could you please delete the reply I made above?

 

Thank you!