Recent content by anders

Off topic, but: I'm probably just going to show I have a very vague grasp of what viscosity is, but wouldn't an incredibly thin gas behave like a fluid with very very low (near 0) viscosity? After all, if there's hardly any interaction between particles at all, there shouldn't be much...

What is \Phi in this equation?

Do you think that is significant? Does helicopter downwash air heat up? Ah, good point. Perhaps one could introduce some kind of dimensionless parameter to model this? Agreed, there is a contradiction. What I meant was that the air would first be set into motion by the rotor, then be blown...

I don't understand what you mean by making an integral momentum balance, and what you mean by relative speed. The relative speed between the rotor and the air? Solenoidality! Hehe, that was a new word for me. I suppose because of the similarity to the shape of the magnetic field around a...

Ok, I agree that the rotors are moving. But the situation might be different from that of airplanes. Each rotor is flying in the wake of the rotor before it. Couldn't this be quite significant? Each rotor is flying in air that is already moving downwards (set into motion by the rotor before...

Hello! First - thanks for taking the time to even begin to answer my question! I agree that 'how strong will the downwash be' is not very clear. What I mean is this: What will the mass flow through the rotor arc be (kg/s)? Classius: You say that the lift equals the product of the mass flow...

Hello! We all know that helicopters can hover, stand still in the air. As they do this, a powerful downwash, down-directed wind, results. This is very obvious when the helicopter is near the ground, since the downwash often kicks up a dust cloud. My question is this: How strong will this...

I think I read somewhere that a very approximate value for the lift coefficient of a flat plate is L=1.05*sin(2*a) where a is the angle of attack (I have to say again that this is just a ballpark figure). Also, the lift-coefficient can be determined analytically for some very simple...

Is it possible to use big gyroscopes to directly control yaw, pitch and rotation of aircraft? Let's make the assumption that the system must be able to produce a specific moment (force couple) for an arbitrary length of time, without the power necessary to do so increasing. An example...