Finding Airspeed: Pressure Altitude, Temp & Mach Number

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In summary, the conversation is about finding various airspeeds and pressures at a pressure altitude of 12km with an ambient temperature 15 degrees Celsius higher than the standard atmosphere, and a cruise Mach number of 0.85. The equations used are Veq = sqrt(sigma)*V, M = V/a, and T = Tsea + a(h-hs). The process involves using the altitude and temperature to find the standard temperature, calculating sigma, and using Mach to find the true airspeed. The difference between correctly and incorrectly calibrated airspeed is unclear from the notes.
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physics_197
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Homework Statement



Pressure altitude of 12km,
Ambient temp is 15 celsius above that of the standard atmosphere,
cruise mach number is 0.85.

Find equivalent airspeed, total pressure at pitot tube, correctly calibrated airspeed, and incorrectly calibrated airspeed (Compression is ignored).

Homework Equations



Veq = sqr(sigma)*V
M = V/a
T = Tsea + a(h-hs)

The Attempt at a Solution


[/B]
Here is my process, please correct if needed, I took the altitude and found out what the temp should be. Then do I go and find sigma by using this temp I just found or use the 15 degrees above it? Then I should be able to use Mach to find the true airspeed and plug those into the eqn to find Veq.

And then, what is the difference between correct and uncorrect? The notes are very bare in these terms.

Thanks, feel free to ask questions!
 
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Can you provide a reference to an online treatment of this topic?
 

FAQ: Finding Airspeed: Pressure Altitude, Temp & Mach Number

1. What is airspeed?

Airspeed is the measure of the speed at which an aircraft is moving through the air. It is typically measured in units of miles per hour (mph) or knots (nautical miles per hour).

2. How is airspeed affected by pressure altitude?

Pressure altitude is the altitude in the standard atmosphere where a particular pressure can be found. As pressure altitude increases, the air becomes less dense, which reduces the airspeed of an aircraft.

3. What role does temperature play in airspeed?

Temperature affects airspeed because it affects the density of the air. As temperature increases, air becomes less dense, which causes a decrease in airspeed. This is because the molecules in warmer air are more spread out, resulting in less resistance for the aircraft to move through.

4. How is Mach number related to airspeed?

Mach number is the ratio of an aircraft's speed to the speed of sound. It is an important factor in airspeed because once an aircraft reaches or exceeds the speed of sound, it enters the transonic and supersonic regimes, which can have significant effects on the aircraft's performance.

5. Why is it important to calculate airspeed accurately?

Accurate airspeed calculations are crucial for safe and efficient flight. A pilot needs to know the airspeed to properly control the aircraft and to determine the amount of lift and thrust needed. Additionally, incorrect airspeed calculations can lead to dangerous situations such as stalling or exceeding the aircraft's structural limitations.

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