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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 ...
6k 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 ...
3k views

How much horsepower to weight is required for a 1:1 thrust ratio?

I did a math experiment today, but wanted to verify the results. I wanted to figure out how much horsepower is needed for an aircraft to hover in midair with no wings/lifting body (1:1 thrust/weight)....
4k 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 ...
3k views

How does blade solidity ratio relate to thrust/power/torque of a propeller?

for quite some time I was using ABBOTT formula for static thrust estimation on a two-bladed propellers: $$T=6.8\times10^{-5}\times D^{3}\times p\times RPM^{2}$$ $T$ is Static Thrust (N); $D$ is ...
2k views

Why do toy (RC) helicopters have curved flat surfaces and larger rotors on true helicopters have a solid aerofoil shape? If the rotor was mechanically strong enough to lift the desired weight, is ...
2k 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 ...
595 views

How much lift is created by a half-sized rotor?

I wonder if lift is directly proportional to the diameter of the rotor disc. For example, if an engine spinning a 26 ft diameter rotor can lift 635 kg, will a 13 ft diameter rotor using the same ...