3k views

How does the nozzle diameter affect the thrust of a ducted propeller?

I currently do some experiments with ducted propellers in which I try to figure out which effect a nozzle has on the thrust produced. My theory goes like this: If I reduce the exit diameter of the ...
• 351
3k views

Is 1 propeller always more efficient than 2?

Based on other answers I've read here (1) (2) (3), a single large blade propeller is the most efficient type of thrust you can get. There are 2 reasons for this (as I understand it). Firstly, ...
• 1,201
3k views

What is the maximum theoretical lift of a plane as a function of engine power and surface of the wings?

Maximum theoretical lift of a plane as a function of engine power and surface of the wings? I know that the maximum static thrust of a propeller turned by an engine of power $P$ can not be greater ...
• 3,371
4k views

Why don't contra-rotating propeller configurations with more than two propellers exist?

I wasn't able to find a single example of more than two propellers stacked axially in a contra-rotating configuration. There is a huge number of contra-rotating propeller setups, but it is always a ...
3k views

How does climb-rate vary with density/pressure altitude?

I'm seeking to write a little web or phone app which can help me choose the best cruising altitude based upon winds aloft. I know Garmin Pilot (and probably Foreflight) have a cruising altitude ...
• 309
691 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 ...
• 1,349
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 ...
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 ...
• 4,411
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 ...
2k views

static thrust vs. prop RPM data?

edit: question was too long, and is actually simple, so I removed unneccesary description Background: There are many questions here about: propeller efficiency changes to thrust when it is dynamic ...
813 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 ...
• 3,524
458 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 ...
451 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
229 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 ...
• 41
1 vote