Autogyro Disk Loading Question
Stephen Lund
I am wondering what might be the theoretical and/or practical MINIMUM
disk loading for an autogyro and what might be the characteristics or
dificulties in flying such a lightly loaded disk?
Steve Lund
xpz...@prodigy.com
Stan Gosnell
XPZ...@prodigy.com (Stephen Lund) wrote:
In order to get a lightly loaded disk, it would have to have a very
large diameter, & this causes all kinds of problems. The longer the
rotor, the stronger it must be just to hold up its own weight, never
mind the strength to lift the aircraft. As it gets longer, the
airspeed of the blade tips increases, perhaps approaching supersonic
speeds. Also, it becomes harder to control larger rotors.
In general, the smallest rotor that can provide enough lift is what
you want. What benefits of light disk loading, if any, are you trying
to ger?
Rob Foster
Varies in direct proportion to the size of your testicles, and/or desire
to meet your maker! Seriously, my gyro instructor said dont even THINK
about less than + 1 g.Erring on the side of caution perhaps,but its
worked for me so far! Rob
Stephen Lund
>In order to get a lightly loaded disk, it would have to have a very
>large diameter, & this causes all kinds of problems. The longer the
>rotor, the stronger it must be just to hold up its own weight, never
>mind the strength to lift the aircraft. As it gets longer, the
>airspeed of the blade tips increases, perhaps approaching supersonic
>speeds. Also, it becomes harder to control larger rotors.
>
>In general, the smallest rotor that can provide enough lift is what
>you want. What benefits of light disk loading, if any, are you trying
>
Actually I have two ideas or goals here....a low power to weight ratio...
and a very low power off sink rate.
The very low power/weight ratio might enable an ultralight autogyro a
greater range or duration.
If a very low sink rate (of perhaps 300 - 400 ft./min.) could be acheived,
it might be possible to actually soar in thermals; the relatively
smaller turning radius making it possible to remain in the stronger lift
near the center of the thermal.
I read somewhere that Igor Bensen's original gyroglider had an empty
weight of just over 60 lbs. and an early photograph would seem to
indicate a 21 ft. dia. rotor. With a 200 lb. pilot this should indicate
a disk loading of approx. .75 lb./ sq. ft. I have no idea what kind of
performance this craft might have had...or what might be possible with
materials and blade designs that are available today, but I find it an
interesting idea to ponder....and thought that some others might have
some data, thoughts, experience, or even opinions on the idea.
Steve Lund
Gene Shimko
Stan Gosnell wrote:
>
>>
> I don't remember exactly who did it, but extensive work has been done
> on a man-powered helicopter, by a university, I think. As I remember
> it actually flew, but it took a really strong pilot. Their work
> should help you, but as I said, I can't remember who did it. Maybe
> the same team who won the Kremer Prize for the man-powered airplane?
> Anyone know if this is available on the web?
Various human powered helicopters have been built during the last 15 or
so years. There are several web sites describing current machines. Not
many have been successful. There is a machine in Japan that hovered for
a short time. The American Helicopter Society has had an ongoing contest
for the first machine to hover for 1 minute and during that time achieve
an altitude of 3 meters. Current machines take advantage of ground
effect to reduce required power. Also, disc loading is necessarily kept
low. No one has claimed the prize yet. It's a lot tougher than human
powered airplanes.
Stan Gosnell
XPZ...@prodigy.com (Stephen Lund) wrote:
>I read somewhere that Igor Bensen's original gyroglider had an empty
>weight of just over 60 lbs. and an early photograph would seem to
>indicate a 21 ft. dia. rotor. With a 200 lb. pilot this should indicate
>a disk loading of approx. .75 lb./ sq. ft. I have no idea what kind of
>performance this craft might have had...or what might be possible with
>materials and blade designs that are available today, but I find it an
>interesting idea to ponder....and thought that some others might have
>some data, thoughts, experience, or even opinions on the idea.
>
>Steve Lund
I don't remember exactly who did it, but extensive work has been done
Eric Scheie
st...@hal-pc.org (Stan Gosnell) wrote:
>
>I don't remember exactly who did it, but extensive work has been done
>on a man-powered helicopter, by a university, I think. As I remember
>it actually flew, but it took a really strong pilot. Their work
>should help you, but as I said, I can't remember who did it. Maybe
>the same team who won the Kremer Prize for the man-powered airplane?
>Anyone know if this is available on the web?
>
There is a human powered vehicles web site, but the address escapes me at the moment. I found
it by doing a web search for human powered aircraft. There is a human powered helicopter
competition sponsored by the American Helicopter Society, and I think FAI will recognize
certain acheivements in that area as well. Last I heard the record endurance for a human
powered helo is 19.? seconds held by a team from a university in Japan I believe.
Eric Scheie
Craig
On 19 Mar 1997 07:55:00 GMT,
Stephen Lund <XPZ...@prodigy.com> wrote:
>I am wondering what might be the theoretical and/or practical MINIMUM
>disk loading for an autogyro and what might be the characteristics or
>dificulties in flying such a lightly loaded disk?
Typical disc loading is 1.2 to 1.4. Below 1.2 the gyro will be more
sensitive to turbulence. But also you will have a slower turning rotor,
making it easier to reach critcal low RPM if "G" loading is reduced.
Also, with a real low disc loading, climbing at a steep angle with full
power, you could potentially dangerously unload and slow down your rotors.
DocCraig
fick...@maroon.tc.umn.edu
AHRMAND
Leonardo DaVinci had a home build kit for a one man helicopter(pilot
powered) but
I don't think it ever got off the ground??? Mr. DaVinci has moved, and
has left no
forwarding address, and I am therefor unable to give you the loading curve
that you
asked about at this time. I will however continue to locate him in as much
as there
are several other questions that I would like to ask him.......I'll keep
you posted on
any future progress. P.S. Someone said that Igor Bensen, and
Mr."D" are
both at the same area code.................Ahrmand
nha...@aucklanduni.ac.nz
> I am wondering what might be the theoretical and/or practical MINIMUM
> disk loading for an autogyro and what might be the characteristics or
> dificulties in flying such a lightly loaded disk?
>
> xpz...@prodigy.com
If you mean wing-loading in cruise - it is a trade-off with flight speed. The bigger the disc, the lower the disc loading, the higher the hover-efficiency (or whatever you want to call it in autorotation - I don't think the momentum argument changes) but the lower the flight speed. Also, there are practical limits to rotor diameter to do with blade-droop and ground-handling. Most designs seem to be around 10 kg/m2. Above that the efficiency falls off.....