Help calculating static thrust for a given engine and propeller

In summary, the conversation discusses the need for estimating the thrust of a turboprop propeller at sea level static. The formula for calculating this is TSFC x HP, with a typical TSFC range of 0.5-0.6. Additionally, the conversation mentions the potential decrease in engine power at higher altitudes and how this can be estimated using the Breguet Equation.
  • #1
Aeroguy101
3
0
Hi guys,

I need to be able to estimate the thrust that a turboprop propeller produces at sea level static. Say I have an 1100 hp pt6a engine and a 80 percent efficient propeller. I have seen formulas that calculate the thrust but you need to be moving. I want to know the static (your airplane is moving at zero velocity) thrust.

Also the next thing that i will need to do is calculate the thrust at any altitude or mach number. Will the engine lose power with altitude, in other words is there power lapse?
 
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  • #2
The formula for estimating thrust at sea level static is TSFC (thrust specific fuel consumption) x HP. The TSFC is usually around 0.5-0.6. So in this case it would be 1100 x 0.6 = 660lbs of thrust. In terms of power lapse, a turboprop engine will lose some power as altitude increases due to less dense air. This can be estimated using the Breguet Equation.
 

1. How do I calculate the static thrust for a given engine and propeller?

To calculate the static thrust, you will need to know the engine's maximum power output, the propeller's diameter and pitch, and the air density. The formula for static thrust is: Static Thrust = (0.5 x Air Density x (Propeller Diameter)^2 x (Propeller Pitch)^2 x Maximum Power Output). Make sure to use consistent units for accurate results.

2. Can I use the same formula for all types of engines and propellers?

Yes, the formula for calculating static thrust can be used for all types of engines and propellers. However, the values used in the formula may vary depending on the specific engine and propeller being used.

3. How does air density affect the calculation of static thrust?

Air density is an important factor in calculating static thrust because it affects the amount of air that the propeller can move. The higher the air density, the more thrust the propeller can produce. Air density is affected by altitude, temperature, and humidity.

4. Are there any other factors that can affect the accuracy of the static thrust calculation?

Yes, there are other factors that can affect the accuracy of the static thrust calculation, such as the efficiency of the engine and propeller, the airfoil shape of the propeller, and the airspeed of the aircraft. It is important to consider these factors when using the formula to calculate static thrust.

5. How can I use the calculated static thrust in practical applications?

The calculated static thrust can be used to determine the maximum weight an aircraft can lift off the ground, the rate of climb, and the acceleration of the aircraft. It can also be used to compare different engine and propeller combinations and make informed decisions for aircraft design and performance.

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