Quote:
Originally Posted by KSagal
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Bob,
I said that the weight of the rider, if below the lift plane would add a level of stability. Are you really saying it would not?
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No. I'm saying it may be more stable than it appears, and not be worth the negatives involved.
Quote:
Originally Posted by KSagal
Just like on a segway, a high weight is a destabilizing factor. Just because when a segway is working properly, it can compensate does not mean it is more stable than if it were designed otherwise.
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Agreed. You are comparing higher/lower and more/less stable. I'm looking at how stable the actual device is. Both are correct. Yours is a basic physical principal. Mine is an estimate. So yours is MORE correct, if you'd like to compare.
Quote:
Originally Posted by KSagal
And most flying machines that I know of have to deal with all sorts of degrees of instability, and the better designed ones can recover from at least some level of it. Any machine designed to not be able to deal with at least some instability will not be much of a success, or use, or even safe.
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Yes, I tried to bring out this point as well. But remember, this is a test prototype, being deliberately operated very conservatively in a very controlled environment. The safety tradeoffs will be different, from a vehicle operated in a wide array of environments and weather conditions, by pilots of various skills, over longer periods of time, with more opportunities for lapse in attention -- any of the host of factors a real-world device must be safe.
Quote:
Originally Posted by KSagal
I guessed the white boxes on the arms below the motors were the battery packs, which would do a reasonable job of distributing the weight. If the entire machine were relatively symmetrical in weight, instead of a central weight and outlying lift arms, it would have a different flight characteristic. I don’t know that it would automatically be more or less stable, but by distribution the weight, individual components and frame members might be able to be made from lighter materials.
I agree, the empty machine (sans pilot) does look like the center of gravity is most likely below the props, but that pilot is a pretty big weight, and does appear relatively high to me.
Still, the whole device seems pretty light, and light duty. I am still curious, and if it came to a town near me, I might glide on over, and check it out.
As far as your first statement that the pilot would not want the thing coming down on him made me think that I would equally not want to fall off my perch and fall onto that field of spinning rotors either.
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I think he's adequately restrained from that happening. But with the assembly being lower to the ground, if he dumps, there's less freedom for it to rotate out of control. If it were above him, it could turn close to 90 degrees.
Also, his position gives him a clear view of many of the rotors, and he can watch both the device and the ground at the same time. I don't think he could do that if he were below it.
As a test setup, it doesn't seem like an unreasonable configuration to me.
Perhaps you're familiar with the Hiller flying platforms? They actually depended on the pilot's weight shifts and sense of balance for stability.
http://www.hiller.org/flying-platform.shtml