240 views

### Can the measured thrust of a propeller be greater than the max thrust predicted by Froude's theory?

Can the measured thrust of a propeller be greater than the maximum possible thrust predicted by Froude's Propeller Theory? Is Froude's theory reliable in practice regarding the upper limit of the ...
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512 views

### How much is a swashplate system more energy efficient than a fixed blade system for the same load

When reading about the lifting capacity of swashplates (as found in helicopters) vs fixed blade systems (as found in e.g. DJI drones), I read a lot of comments about the fact that the bigger rotors of ...
• 117
965 views

### Would large, low aspect ratio fan/propeller blades be more efficient? Why not?

With reference to this answer We read in the above that accelerating a larger mass of air by a smaller amount is (theoretically) more efficient. This is an advantage of a larger propeller than is ...
18k views

### Is there any equation to bind velocity, thrust and power?

I am designing a remote controlled airship. I will tune it so that the lift given by Archimedes' Principle will exactly balance the weight of all the structure. It will be propelled by brushless ...
• 383
695 views

### How much energy/prop efficiency does the e-volo copter sacrifice by having a smaller propeller?

It seems like on an electric aircraft, it would be very important to have a high energy efficiency. Wouldn't the e-volo copter be much less efficient due to the small radius of the propellers when ...
• 1,359
616 views

### Matching the Drag Equation to Real Airplane Data

I am trying to compute airplane performance for a piston-driven airplane with constant speed prop using the standard equations for Lift, Thrust and Drag. I have found that there are a couple of useful ...
• 1,013
3k views

### Is there a special way to calculate the (parasitic) drag produced by the propeller?

Is there a special way to calculate the drag produced by the propeller? Can I compute it with the standard formula for parasitic drag, with the circular area of the propeller as the wetted area? To ...
2k views

### What is the difference between types of propeller? [closed]

I have been noticing almost every Multirotor vehicle uses a single thin double-bladed propellor on each axis. And yet clearly, there are some that do not fit the norm. Can someone explain what the ...
134 views

### What is the range of ratios between optimal propeller efficiency and true propeller efficiency?

In https://aviation.stackexchange.com/a/15383/20394, the optimal prop efficiency is given as: \eta^{opt}_{Prop} = \frac{1 - \frac{\Delta v\cdot \left({v_{\infty} + \frac{\Delta v}{2}}\right)}{d_P^2\...
• 5,172
2k views

### Is there a mathematical formula to find the most efficient propeller? [duplicate]

Is there a mathematical formula to find the most efficient propeller? Is a five-blade better than a four-blade? Does software exist to aid in the calculations there?
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1 vote
183 views

### Is flow attached at fixed propeller blade at every RPM / speed conditions?

Propeller blade AoA depends on tangential veloctiy caused by rotation and forward speed "head wind". If propeller has fixed pitch is flow attached on blade at every RPM / speed conditions? ...
1 vote
94 views

### What are some first-order drag approximations for airframe/propwash interactions?

What are some first-order drag approximations for airframe/propwash interactions, both for dynamic flight and for static thrust, in a traditional tractor configuration?
• 5,172
1 vote
416 views

### How energy efficient is an aircraft take off?

How much work is generally done by an aircraft (e.g. B737NG) in order to reach V_rotate, and how does this compare to the energy content of the fuel that is used?
• 11
1 vote
3k views

### What is the Efficiency of Cessna-150's Propeller?

From that Cessna-150's data, it used Continental 0-200-A 100 HP (75 kW) at 2,750 RPM and with Fixed Pitch propeller with its diameter=69 inches. If power is delivered maximum to the propeller (through ...
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