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    Lazair on Floats with Rotax 185's needs more power, Ideas?

    I can't tell you anything about this particular set up. But theoretically speaking, 5500 rpm would be a 10% increase above 5000 rpm. Torque is proportional to the square of rpm. So the torque on the propeller shaft would be increased 21% (because 1.1x1.1=1.21). The horsepower needed to increase...
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    Lazair on Floats with Rotax 185's needs more power, Ideas?

    That's the way I figure it too.
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    Lazair on Floats with Rotax 185's needs more power, Ideas?

    An increase of horsepower from 9 to 12 is a 33% increase. So your new horsepower will be the old horsepower times 1.3333333. Horsepower is proportional to the cube of rpm. It takes 8 times as much horsepower to double the rpm. So HP1/HP2 = (rpm1/rpm2)^3. So if (rpm1/rpm2)^3 increases by a factor...
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    Tail boom strength

    How does the vertical tail loading compare to the horizontal tail loading?
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    Tail boom strength

    Do you have any idea why control surfaces can be designed with lesser loads? It seems like a 100 mph wind will give the same lift per square foot on a control surface that it would on a wing surface. I can see how a sudden updraft would cause increased loading of the wings, but decreased loading...
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    What did you do on your airplane project today?

    Riveted some leading edge. I'll let the students finish up.
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    Patenting a design

    I heard a fellow say, one time, "I love that new wife smell." Congratulations on landing her, and thanks a lot!
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    Patenting a design

    Maybe so. An article I recently read said most patents are worthless. A high school friend, who is president of the largest lawn mower blade manufacturing company on Earth, owns at least one patent and he isn't wild about the idea of getting a patent. He says someone can tweak something and say...
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    Patenting a design

    Kinda like this:
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    Patenting a design

    This wing has in-flight-adjustable washout. This feature should make spin recovery much easier, even--and especially--in instrument meteorological conditions. A few years ago a Gulfstream engineer spoke to the Vidalia Experimental Aircraft Association. But he didn't come to talk about...
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    Patenting a design

    How do you decide whether or not an airplane design should be patented?
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    Wing strut compressive load test.

    Yes, Fe is Euler stress. Thanks for telling me about Bruhn.
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    Wing strut compressive load test.

    We were thinking about 35 inches of bigger pipe in the middle, with 25 inches of existing pipe on each end. But the jury strut is certainly something to consider.
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    Wing strut compressive load test.

    Now we need to figure out how long a teardrop-shaped pipe, riveted to (outside of) this existing pipe, will increase the strength by a factor of 2.7.
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    Wing strut compressive load test.

    The load is the difference in my weight pulling on the lever, which was 50 horizontal inches away from the pivot point of the chain binder. The logging chain parallel with the compressed strut was in a line 1-7/8 inches away from the pivot point. The strut buckled when 42 pounds of force was...
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    Wing strut compressive load test.

    Thanks, Bilski. This is EMT, not 4130. I used the equation I found on assakkaf.com (Fcr=0.877Fe) and obtained 1,216 pounds (assuming 36,000 psi yeild stress and 30 million psi Young's modulus). We'll find out tomorrow how strong it is when we test it.
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    Wing strut compressive load test.

    This backhoe trailer was used to test several wing truss and tail boom mock-up components. It was also used as an anvil to hammer out wing trailing edges. It's a handy work bench. The wing strut mock-up is attached, at one end, to the top of the A-frame. The other end is attached to the wing...
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