Recent content by E'lir Kramer

Apparently my idea actually works in theory. Or at least, aircraft designers at Georgia Tech have designed a STOL fixed-wing aircraft based on the same principle, which is that the apparent airspeed over the wing is what generates lift. They're calling it a "blown wing" design...

How does the foil know that the air which is moving over it is compressed air and not "free" air? It just sees air moving over it. We already agree that a foil in a stationary tunnel experiences lift. What's the difference here? From the frame of reference of the foil there is no difference...

I understand that my question leaves this interpretation open, but this is what I had in mind: https://docs.google.com/drawings/d/1WhC7r3491KIbeSNgewC9NnJqyDCJpwl46nwnKOSw6WY/edit?usp=sharing The air would be deflected out of the back of the craft, not touching the walls. The difference...

Could an aircraft achieve lift by blowing a fast stream of air over an internal fixed wing? I.e., by having an onboard wind tunnel with a wing suspended inside? Couldn't that be used to achieve fixed-wing VTOL without a T:W ratio greater than one?

Ok, this is clearly the source of my confusion. And, I suppose I still don't understand how that is true. It feels like violates a conservation law, but actually I see now that it doesn't. (Though I don't understand how it's true, I can see that it's not impossible). That's true! I didn't...

Let me put this another way. I don't understand how a plane can take off when its thrust to weight ratio is less than one. Yet, many planes do so. The 747-400 has a T/W of 0.27. Can someone explain how a plane can take off (and a fortiori stay aloft) when its T/W is less than one?

I understand that this is the assertion. I am hoping someone can come in here with a more convincing analysis. At the moment that liftoff occurs, the lift on the airfoils is 9.8x N. Thus the drag is > 9.8x N. If the engine is not producing 9.8x N of thrust, then the plane slows down and the...

I am studying to be a pilot and something I've read in the book confuses me. It is that Vertical Takeoff and Landing (VTOL) engines need to be heaver than their corresponding traditional takeoff/landing counterparts. Wikipedia says the same thing here. I am going to interpret "larger" and...

Funny story, but |A| is 60, not 55. Proof by enumeration: Prelude> length [ (i,j) | i <- [0..10], j <- [0..10], i /= j, (i + j) <= 10] 60 Prelude> *[ (i,j) | i <- [0..10], j <- [0..10], i /= j, (i + j) <= 10]...

Ohh, thanks. I see his thought process now in his answer. Anyway, we are right, and I just confirmed that in Haskell. So I'll email him with the revision. Haskell program: Prelude> length [ (i,j) | i <- [0..10], j <- [0..10], i /= j, (i <= 5 || j <= 5)] 90

This is a solved problem and I am having a hard time working through the answer. Question . Choose two numbers uniformly but without replacement in {0,1,...,10}. What is the probability that the sum is less than or equal to 10 given that the smallest is less than or equal to 5? Answer...

Thanks for the link, Tim! That fully clears it up for me. One of the biggest frustrations with mathematics self-study is that it math isn't a linear progression of knowledge, but rather a web of knowledge, and whatever thread I pursue is constantly touching other threads which are still in the...

Makes sense, thanks.

Here's another. Now, what does 2^{\Omega} mean in this context? Omega is a set; how do you raise an integer by a set?

Oh, I think I get it. It is fair to say that the big cup in \bigcup _{n}A_{n} should read like \sum_{n}A_{n} in big sigma notation?