What is the equation for approximating propeller thrust at a known RPM?

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    Propeller Thrust
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SUMMARY

The discussion centers on calculating propeller thrust at a known RPM, emphasizing the importance of propeller efficiency, engine horsepower (HP), and velocity. Users reference Raymer's book "Aircraft Design" by AIAA, specifically page 396, for detailed equations and methodologies. The distinction between static and dynamic thrust is highlighted, particularly in the context of FAA-certified aircraft versus model airplanes. Additionally, proprietary information from manufacturers like McCauley is noted as a potential resource for accurate data.

PREREQUISITES
  • Understanding of propeller efficiency metrics
  • Knowledge of horsepower (HP) calculations
  • Familiarity with thrust measurement concepts
  • Basic principles of aerodynamics related to propellers
NEXT STEPS
  • Study the equations for thrust calculation in Raymer's "Aircraft Design"
  • Research propeller efficiency and its impact on performance
  • Explore the differences between static and dynamic thrust
  • Investigate proprietary data sources for propeller specifications
USEFUL FOR

Aerospace engineers, aircraft designers, and hobbyists involved in propeller design and performance optimization will benefit from this discussion.

thomasxc
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Is there some equation i can use in order to approx. find the trust created by a prop at a known RPM??




-Tom
 
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prop websites normally have this graphed, though as you may know, static thrust is different than dynamic thrust.

I designed an airplane and competed with it once.

Attached is my teams report. You may find some interesting information in this document.
Pg 24 talks about thrusts and stuff.

enjoy...
 

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thomasxc said:
Is there some equation i can use in order to approx. find the trust created by a prop at a known RPM??

-Tom

You can look up the propeller efficiency. You need to know this number, along with the velocity and HP of the engine to calculate the net thrust.

Page 396 in Raymers book, "Aircraft design" by the AIAA explains this.
 
Nick Bruno said:
prop websites normally have this graphed, though as you may know, static thrust is different than dynamic thrust.

I designed an airplane and competed with it once.

Attached is my teams report. You may find some interesting information in this document.
Pg 24 talks about thrusts and stuff.

enjoy...

Actually, that's proprietary information they don't give on their websites. I've had to call up the engineers at McCauley to get this information.

I think you are talking about model airplane propellers, whereas I am talking about propellers for FAA certified aircraft 2000lbs+.

Nice CAD drawing. All in all, looks like a very fun senior design project (if that's what it is).
 
yes, i was talking about models :).

and yes it was a senior design project. was a lot of fun lol
 
Cyrus said:
You can look up the propeller efficiency. You need to know this number, along with the velocity and HP of the engine to calculate the net thrust.

Page 396 in Raymers book, "Aircraft design" by the AIAA explains this.

Agree, energy method is very useful at initial sizing and that suits you case.
But make sure you get the loading rate that's a good problem.
 
I have encountered a vertically oriented hydraulic cylinder that is designed to actuate and slice heavy cabling into sections with a blade. The cylinder is quite small (around 1.5 inches in diameter) and has an equally small stroke. The cylinder is single acting (i.e. it is pressurized from the bottom, and vented to atmosphere with a spring return, roughly 200lbs of force on the spring). The system operates at roughly 2500 psi. Interestingly, the cylinder has a pin that passes through its...

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