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  1. H

    Discussion: Conceptual Design of an "Inexpensive" Single-Seat Motorglider

    Tough one, since that's below Vmc for Concorde. I'd put L/D at 145 mph somewhere between a brick and an anvil. :grin:
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    I was bored last night so I designed a seaplane

    Then why don't you get us a mile closer? Post a sketch of what you're talking about, because I don't understand your point.
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    bendy wings ?? how much bend is practical and what are advantages ? any of non ??

    Re: bendy wings ?? how much bend is practical and what are advantages ? any of non ? It will vary from design to design, but a rough guide I've heard is 1" of deflection per g. This number came from Orion, a professional aircraft designer who, sadly, is no longer with us.
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    Lightest Plane in the World: Design Criticism and Discussion

    The Pietenpol Sky Scout is far from the lightest aircraft in the world. Weights will vary some, but it has an empty weight of 250kg. Another plane of similar configuratin, the Fly Baby, has an empty weight of 274 kilograms. This gives a pretty general idea of where single seat wood and fabric...
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    Cruciform tail for 3-axis control?

    Recall that the early Rutan Vari-EZ's had differential elevons on the canard for pitch/roll control. Burt Rutan later added ailerons to the wing after early builders reported poor roll authority. A cruciform tail could work, but run the numbers to see what the control authority is.
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    Take Measurements of Drawings and Much More

    Neat tool, but the thought of scaling drawings for fabrication purposes makes me shudder.
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    Very low aspect ratio planes?

    What is the design methodology for this sort of configuration? Do you start with the planform?
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    Please Critique this strut design

    You should be able to figure out the stresses involved. Here's a link to some formulas for screw threads. I have some of this on my computer at work, but I don't have access to it right now. Screw thread Calculations
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    (Electric) Self Rotating Wing

    I managed to track down one of the OP's threads on this concept on another forum. The configuration in that thread is one where there is a wide-chord rotor with propellers out near the tips. The rotor is rotated by the propellers. I saw no mention of the control system, but all of the OP's posts...
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    Pipistrel Panthera first flight

    +1 on Autoreply. The t-tail has lower drag and the necked down fuselage has less wetted area and is more efficient structurally. It's part of what gives the aircraft it's performance.
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    Recreational slow, draggy, solar ever-flying bi-plane: Is it possible ?

    Not likely. 2000 watts is only 2.6 horsepower. Drag is your enemy here.
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    Engine size developement in jet aeroplanes !

    I usually stay out of this sort of thing, but you're missing a critical concept of supersonic aerodynamics. Wave drag is a function of the distribution of the cross sectional area, not frontal area. Volume Wave Drag
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    Engine size developement in jet aeroplanes !

    I don't think you're doing your drag buildup correctly. BTW, aircraft drag coefficients use the reference wing area.
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    Flying wing with pitch control canard?

    Limit the control authority of the elevators/elevons so they can't raise the angle of attack enough to get past the critical angle of attack. Whether this is advisable is another matter entirely.
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    experiamental fighter jet style aircraft

    Don't let the picture fool you. Rare Bear's tailwheel is adequately sized. Remember that a Bearcat is a BIG airplane. The prop is 15 feet in diameter.
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    experiamental fighter jet style aircraft

    Like anything turbine powered, if you have to ask what the fuel bill is you can't afford it. Efficiency is nice, but remember that in many cases time is more precious. That, and being able to climb over the weather is useful.
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    experiamental fighter jet style aircraft

    And the Rocket will probably cost the same to build when all is said and done.
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    XFLR5 and inverted airfoils

    What he's getting at is that the airfoil doesn't care which way is up. All it cares about is the angle of attack and velocity. The data will be the same whether the foil is upright or upside down.
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    Orion's "Composite Think" in Plywood???

    Absolutely not. I have always assumed a factor of safety of at least 2 in my design exercises. And you're absolutely right about the properties of the part after milling, drilling, riveting, etc. I wasn't trying to say that you can look at a test report and design the component so the failure...
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    Orion's "Composite Think" in Plywood???

    I beg to differ when it comes to the metals. Every batch (heat) of material from the mill gets tested for mechanical properties and chemistry. The basic sample undergoes a standardized tensile test that tells you the yield strength, the ultimate tensile strength, the reduction of area, and the...
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