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  1. S

    Legal question about copyright

    Cm Been in use for at least 100 years: Pumped-storage hydroelectricity - Wikipedia
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    Static thrust

    Having worked in prop and helicopter rotor aero for several years, I can say that we never talked about torque. The structures and gearbox guys did, because, well, bolts, bending moments, and sizing shafts and things like that.
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    Pitch vs angle

    Pitch and radius have to be in the same units (inches, meters, feet, furlongs, whatever). The angle returned from arctan will be in radians or degrees, depending on how your calculator's set. In a spreadsheet, it will return radians.
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    How to do what I want without using a 3LS design ?

    Forward sweep isn't common because it tends to require much more torsional stiffness. While there are advantages, especially at high angles of attack, when compared to sweep back, a swept-forward will will need to be much stiffer than a straight or swept back wing to avoid aeroelastic...
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    How to do what I want without using a 3LS design ?

    Instead of the Do335 layout, try that of the Do28:
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    How to do what I want without using a 3LS design ?

    Two place twin? Who remembers the Wing Derringer?
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    How to do what I want without using a 3LS design ?

    This way they could use pretty much all the existing tooling for the fuselage and landing gear.
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    Crashes in the News - Thread

    I have a warm spot in my heart for the BAe 146, since I got a nice 5-week stay in the UK while BAe was clearing the engines' ability to deal with icing in altitude conditions. The NGTE, in Pyestock, was definitely cool (hey, I'm an engineer), as was the plant in Hatfield, where BAe's...
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    You thought amateur drones were dangerous, what about the jetpacks?

    Or observant enough to notice the large aircraft.
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    The Prop windmilling on RX1/Apex engines

    The answer is yes. A freely windmilling prop will have more than one slowed by being attached to an engine.
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    The Prop windmilling on RX1/Apex engines

    Generally, windmilling props have higher drag than stopped props, which may be important. For a crankcase-scavenged two-stroke, it’s probably important to make sure engine isn’t windmilled, as fuel flow is likely needed for lubrication, but four-strokes use engine-driven oil pumps.
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    Contra rotating propellers

    Not that again. No. Fewer blades are not always more efficient. We've discussed this numerous times in the past. Like any other lifting device, a propeller's drag is from a mix of induced and skin friction drag. Increasing the number blades reduces the total induced drag. The optimum...
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    Boeing - Design Issues...

    Think of the reaction at Oshkosh
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    Boeing - Design Issues...

    Perhaps an F-104 derivative would be a better choice? I present the Lockheed Lancer. The bigger wing would help. Getting the right engine would still be tough, but I'm sure that a surplus RB.199 would be relatively cheap and has the advantage of lower sfc for cruise than the J-79 or F-100...
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    Contra rotating propellers

    It takes no more energy to remove the swirl from the forward propeller than it cost to put it there in the first place; it's a result of the downwash that results from the lift of the propeller blade. The net result is that coaxial props have a net efficiency about 1 to 3% greater than single...
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    Ultralight struts/cantilever/additional weight

    A high wing will have the struts in tension during flight; this will mean they are lighter and smaller. They will also tend to cause less interference with the wing than struts on a low-winged aircraft, which will need to be in compression in flight, so their size will be determined by...
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    Propeller position research?

    The NACA did a series of experiments to find the best vertical location of propellers in relation to the wing; I believe they found the best was to have them below the wing by some amount. Here are some articles to check out...
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    Contra rotating propellers

    If you're driving coaxial propellers with separate engines, making a center-line thrust twin, the mechanical complication may be worth it. Of course, to make the two systems independent, the engines will need to be as isolated as possible, with independent ignition, induction, exhaust, and...
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    $10 gallon Avgas

    Saudi Arabia, especially, has a very low marginal cost of production: they can increase output quite a lot without any significant increase in operating costs. I suspect the same applies to Russia. The effect -- it may even be the plan -- will be to push high-cost petroleum and alternatives...
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    An argument in favor of multi-engine design

    The presence of propellers increases drag, but altering the lift distribution along the wing. Some modern aircraft will tailor the wing to minimize the effect during cruise, but doing so requires a good CFD program, with a rotor module, and it will only be minimized at one condition. For...