# Recent content by Dave Hodges

1. ### 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...
2. ### Lazair on Floats with Rotax 185's needs more power, Ideas?

That's the way I figure it too.
3. ### 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...

5. ### 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...
6. ### What did you do on your airplane project today?

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

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

Thanks
9. ### 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...
10. ### Patenting a design

Kinda like this:
11. ### 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...
12. ### Patenting a design

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

Yes, Fe is Euler stress. Thanks for telling me about Bruhn.
14. ### 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.
15. ### 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.