Extra large Helicopters

[Eddie]

Building a helicopter with one rotor twice as nowadays big would be problematic as the rotor's ends would break the speed of sound and explode.

Only if you don't halve the rotational speed in the process. This leaves the average linear speed constant, and therefore the average lift per blade-inch will also remain constant. Since lift per blade-inch is constant, doubling the blade length will double the lift.

Anyone who's taken fluids recently care to refute?

Yes you do get the same average linear speed but I wouldn't have thought the total lift would double because half of the blade would be traveling as a lesser speed than the innermost part of the shorter blade. So you'd get either 1.25 or 1.5 times the lift as the original. I don't really want to stress my mind out right now to see if that's right or not though.

[DaleStan]

Yes you do get the same average linear speed but I wouldn't have thought the total lift would double because half of the blade would be traveling as a lesser speed than the innermost part of the shorter blade.

Wait. What? The innermost point of the shorter blade is traveling at a linear speed of (to a first approximation) zero. I'm quite sure no point on the longer blade is traveling at a negative speed. (In fact, "negative speed" is a contradiction in terms. Speed is a magnitude, and hence always non-negative.)

The innermost half of the longer blade is at the same average linear speed as the innermost half of the shorter blade, not slower. This is the same problem as before, just with blades half as long.

Please be more specific about what you mean by "part".


Yes, I did consider stall speeds the first time around. The ratio of wasted (below stall) blade length to total blade length is the same for any two blades with the same linear speed at the blade tip.

[Eddie]

Fair enough, I was being short sighted. Best thing to do would be to Google 'Propeller Thrust Calculator' or similar and plug in some of the variables in question with equal constants elsewhere.

[PikkaBird]

Of course, if you want that doubled lift to actually lift the ship instead of bending the blade, you need to (double?) the stiffness of the blade and the strength of the swashplate components. The collective servos will also need to be (four times?) more powerful to overcome the additional forces.

There are reasons why larger helos have more blades, rather than bigger disks.

[athanasios]

Dudes, this a games forum, not an engineering one.
Graphics first and we can correct the rest at a later time. Don't get stuck with the blades. First we need to have the sprites for the hull.

[APDAF]

How about 4 small rotors in pods?

[gks]

ch54_01.jpg (34.58 KiB) Viewed 2665 times

Something like this is neccessary.
Just think that you have an industry in between two montains...this helicopter can cayy like a container of cargo no?

[Korenn]

yes, that's what the big empty bit is for beneath the helicopter, to fit a container.

[555gln22]

Payload is approx 9t on one of those. I think this is the heaviest lifting chopper in the world, the Russian MI-26:



http://en.wikipedia.org/wiki/Mil_Mi-26

[Grigory1]

Mi-26
Useful loading: 20000 kg of cargo in a cabin or 18500 kg on a suspension bracket.

[gks]

I had a magazine somewhere talking about heavylifting helicopters,i should find it.

[DaleStan]

I think this is the heaviest lifting chopper in the world

Strange. I would have expected the heavy-lifters to be double-rotor choppers. But Airliners.net agrees with you.