Homemade Helicopter: For the People.

Mech_Engineer

What machine are you referring to? Link?

mtworkowski@o

It's line from the 1965 film "Flight of the Phoenix". Hardy Kruger is very convincing as an aeronautical engineer.

mtworkowski@o

RonL
Well said and worth saying.

Mech_Engineer

A helicopter that is able to fly out of the ground effect (e.g. altitude greater than the rotor's diameter) will have larger power requirements, hence why the human-powered Davinci helicopter's power requirements are not applicable. Given that the Davinci copter was at an "altitude" of 8in, and has a blade diameter of 50 feet, it was obviously well within the ground effect phenomenon.

http://www.cavalrypilot.com/fm1-514/Ch2.htm

mtworkowski@o

Mech Engineer,
That website was very informative and easy to read. Just the thing for dopes like me. It reminds me of a book I read 30 yrs ago. Calculus Made Easy by Sylvanus P. Thompson. Motto: Cut to chase. I like those simple explainations.

DaveC426913

"Heh heh heh heh HAH HAH model planes HAH HAH He builds model planes! AH HAH HAH HA HAH"

(I have the 1:72 scale Flying Boxcar model kit still in its shrinkwrapping waiting for the day when I build the diorama of the film.)

FredGarvin

It's what Army aviators need in their instructional sources. No big words. Just the way we like it.

mtworkowski@o

DaveC426913,
thank you for recognising a joke. By the way that was a great movie. Check out IMDB.COM. Some interesting stuff. Out......














S

RonL

Might be that your a "real engineer"

1.The Wright brothers had instant success, and acceptance ?

http://en.wikipedia.org/wiki/Wright_Brothers#Childhood

2.Model airplanes, and real ones powered by rubber ?

http://www.rubberbandit.org/

3. The power of leverage has been, and can be used almost everywhere.

http://en.wikipedia.org/wiki/Image:SFTMHandcar.jpg

If one man can supply movement to things like this, stop and think of how a double acting piston can move air through a rotor, to tip jets.
The first few strokes will be harder, then as the air pushes the rotor to faster RPMs the movement of the piston becomes much less of an effort. (think of a rotor moved by air, as a streamlined balloon, like the example of Newton's law in almost every physics book).



Gyro pilots prespin their rotors by hand, which reduces the takeoff distance required.
All I'm trying to say, is things that seem too simple, or, not likely to work, get passed over very quickly.

Because of limits on budgets this kind of, "crazy stuff" falls into the realm of modeling in most cases.

"There's POWER in crazy stuff"

Ron

mtworkowski@o

Right on Mr. Ron.

FredGarvin

For a pure hover, more power is required than what a fixed wing will need for a rolling take off. The numbers won't lie if you apply them correctly.

mtworkowski@o

That even seems intuitive. Analogous to winding roads going up a mountain as opposed to trying to drive straight up the side. But I would thind more power would be required throughout he whole flight, as compared to fixed wing. Are you saying that hover requires more power than cruising along?

RonL

Fred,
I agree that you are correct with that statement. (which takes me back to this post)

Can this question be answered using the information provided? I think blade width, and airfoil design can be adjusted based on other performance needs, but for pure hoover (above ground effect).

I feel it will be beyond human power, but far less than most people would think.

Mech_Engineer

I've done quite a bit of research into power requirements for helicopters (and airplanes), and the definitive answer is there is no definitive answer. Calculating the power required depends on too many variables like efficiency of the rotor, geometry of the body, altitude, air properties, etc. Basically, all you can do is look at a bunch of different helicopters and their power/weight ratio for an attempted scaling (although scaling linearly is probably not accurate).

That being said, ultralight helicopters in the "economy" performance category tend to have about 40 hp for a gross weight of 400-500 lbs. That is considered a "bare minimum" power requirement, and higher-performance versions will have 70-100 hp for the same weight. Interestingly, ultralight airplanes in similar GWR classes have similar power requirements (but ultralights with 40hp are considered sluggish).

Example: G-1 Ultralight Helicopter

Regarding tip jets:
http://en.wikipedia.org/wiki/Helicopter

Example of a tip-jet helicopter: YH-32 Hornet

Mech_Engineer

Some very cool "helicopters" are the Fairey FB-1 Gyrodyne and the Fairey Rotodyne. They are very cool mixing of tip-powered rotor technology and autogyro technology.

Dragonich

Hi Guys,
I'm new - I just joined about 30 seconds ago, after seeing this page. Me and my friend (though pretty much just me) are working on making our own aircraft. I'm covering helicopters, and he's meant to be covering fixed-wings. Anywayz, I've been testing out some very basic fuel (bi-carbonated soda+vinegar) but I'm trying to make it be released slowly, as right now it's going out in less than 2 seconds. I've tried a couple of thing but they've failed. So, my question to anyone who can be bother answering this (thanks if you do), how could I make bi-carbonated soda+vinegar be released slowly?

RonL

What are you using as a pressure vessel ?