Linked Questions

33
votes
5answers
12k views

How does a fan differ from a propeller?

Why is the fan in a turbofan different than a propeller in a small airplane? Why do propellers typically have 2 or 3 blades, but the fan has a lot more? And why is the fan shrouded but the propeller ...
17
votes
4answers
7k views

Why are three-bladed helicopters relatively rare?

I admit that this observation is entirely subjective, but it seems to me that there three-bladed rotors are significantly less popular than two or four. Factors that I'm guessing contribute - ...
9
votes
4answers
6k views

Does a 4 bladed prop have almost twice the thrust of a 2 bladed prop?

Does a 4 bladed prop have almost twice the thrust of a 2 bladed prop? As a general rule, I'm told GA planes generate 4 lbs of thrust per horsepower. (Source: Zenith School of Airplane Design, Flying ...
46
votes
3answers
19k views

Why is the Tu-95 so efficient despite having propellers that spin faster than the speed of sound?

I've ready many, many times that propellers are not efficient near the speed of sound because it's so hard to get a tip-speed above Mach 1. Then I came across this: It's the Tu-95 "Bear", a ...
26
votes
2answers
29k views

What are the advantages of more than 4 propeller blades?

I have heard that propellers with more than four blades are not as efficient as 4 or less blades because of lower thrust which may result from interfering prop-streams. But I see the ATR-42/72 and ...
26
votes
2answers
7k views

Is it possible to fly with counterbalanced single blade engines?

Refer the image for counterbalanced single blade (Source http://www.aviastar.org/helicopters_eng/bo-103.php). In ground school, they took us for aircraft inspection at end of our ground school ...
1
vote
2answers
379 views

Why Consumer Drones don't use multi-blade (more than 2) propellers?

Maybe unusual question but it's related to Aviation world, even if is more directly related to Drones one. Why almost all consumer drones like DJI's and Yuneec's ones (but it's true also for other ...
19
votes
1answer
5k views

Why don't aeroplanes use propellers with more blades like the intake on a fanjet?

The air intake on a fanjet typically has many small angled blades. A wind pump in an American film might have many broad slatted blades. My desk fan has 3 very large scooping blades and seems quite ...
2
votes
1answer
1k 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?
1
vote
1answer
122 views

Is there any equation on propeller thrust that takes into account the number of blades [duplicate]

I had a look at both What is the equation for calculating static thrust? and Is there any equation to bind velocity, thrust and power? However, it does not mention how much would the thrust be ...
1
vote
1answer
8k views

How to calculate the thrust of a piston or turboprop engine? [duplicate]

This spawns from a related question. Propeller-drive engines (piston/turboprops) seem to always list their output in horsepower or kilowatts, which are units of power. I want to know the engine's ...