CFM conversion to thrust Help

  • Thread starter addzkebabs
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    Cfm Thrust
In summary, Addz is a new member seeking help with converting cfm to thrust. They have found a formula, but are struggling to understand it. The formula involves calculating mass flow rate and velocity using Newton's Second Law of Motion and the length of a propeller blade. The final equation for thrust also includes density and the area of the propeller blade. Addz specifically needs help understanding the calculation for the area of the blade.
  • #1
addzkebabs
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Hey guys! I'm new to the forums here and was after some help for something that I am currently working on. I need help converting cfm to thrust, i have found the formula though i can't get my head around it.

Here it is:

CFM = Cubic Feet per Minute = Volumetric Flow Rate

Mass Flow Rate = (Density) x (Volumetric Flow Rate)

Newton’s Second Law of Motion: Force = (Mass) x (Acceleration), or F = ma

F = ma = (Mass Flow Rate) x (Velocity), given a constant flow velocity
(i.e., constant propeller speed and pitch angle).

Velocity = (Volumetric Flow Rate) / (Area), where Area = (Pi) x (r^2), the
length of a propeller blade is a good approximation for the radius, r.

Thrust = (Density) x (CFM^2) / ((Pi) x (r^2))


The amount of cfm i need to convert is 2750cfm. Any pointers?

Cheers, Addz.
 
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  • #2
Ummm... to be a bit more specific I'm having trouble with this segment:

Area = (Pi) x (r^2)

What is r^2?

Although most likely dead simple for you guys, it isn't for me so don't kill me lol! (I'm really new to all of this so thanks)

Cheers, Addz.
 

Related to CFM conversion to thrust Help

What is CFM and how does it relate to thrust?

CFM stands for cubic feet per minute and is a unit of measurement for the volume of air flow. It is commonly used in the aviation industry to measure the amount of air that a jet engine takes in and expels. This air flow is directly related to the amount of thrust that the engine produces.

How is CFM converted to thrust?

The conversion of CFM to thrust is not a simple calculation as it depends on various factors such as the type of engine, altitude, and air temperature. In general, a higher CFM results in a higher thrust. The conversion can be done using specific engine performance charts provided by the manufacturer.

Why is CFM conversion to thrust important?

CFM conversion to thrust is important because it helps engineers and pilots understand the performance and capabilities of a jet engine. It allows them to make informed decisions regarding aircraft design, engine selection, and flight operations.

What is the difference between static and dynamic thrust?

Static thrust is the amount of thrust produced by an engine while it is stationary on the ground. Dynamic thrust, on the other hand, takes into account the forward motion of the aircraft. Dynamic thrust is typically higher than static thrust due to the added force of the air moving through the engine.

Are there any limitations to using CFM conversion to thrust?

While CFM conversion to thrust is a useful tool, it is important to note that it is not the only factor that determines an engine's performance. Other factors such as engine design, aircraft weight, and external conditions can also affect thrust. It is also important to use accurate and up-to-date data for the most accurate conversion.

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