Paul,

Do you have details on autogiro's running rotaries ? Pardon my
thoughts, but I think a rotary would work well.


Thanks,

Barron

I don't have any dwgs but Gary Buster might help you out.

http://www.youtube.com/watch?v=QOwb8QRHrMY

Paul Lamar



Back in the days of the late Cierva and before the Advent of the
helicopter the autogyro was quite a capable machine. It had heavy two
or more bladed rotor systems which stored a great amount of energy.
Todays autogyros on the other hand in my opinion as a rated Chpl with
IFR must be the daftest thing out there. Flimsy contraptions with
energyretention on the scale of a chopstick. You would not find my
behind in One of them on a calm, stable day let alone in any kind of
turbulence. Surprises me they are legal.

Lutz Strobel

Have you looked at the you tube video?
http://www.youtube.com/watch?v=QOwb8QRHrMY

I filmed the video. Looked pretty good to me. However it was a calm
day.

IMHO the main problem is MPG.

Paul Lamar

Actually the main problem is negative G's When that happens the disk
is no longer loaded and looses momentum, which is where the lack of
stored energy due to the low mass of the rotor system comes in....
the second severe problem is the underslung rotorsystem most of the
nowadays ( refuse to callem modern ) autogyros employ. It can kill
You fast. In summary stay away from them, even if a crash of one of
them would have nothing to do with being powered by a Rotary engine,
it would still rub off. - Lutz Strobel


We are not doing outside loops here :)

There are a lot of them in the States. If the accident rate were much
higher than other experimental aircraft the FAA would be all over
their case.

Paul Lamar


A lot of people think a gyro works by weight shift, it does not, the
teetering rotor and gimbal head allow the rotor to in effect change
pitch around the circle as the advancing blade would have more lift
than the retreating blade if it did not teeter They are not as simple
as they look.

John Evans



Lutz you should try them although I think no one could pursuance you
to do so now.  They are fun and safe, and handle turbulence very
well.   If fact you do not feel any at all even in very high wind.
The "rigidity" which is the percent of lifting surface in the whole
disc is very small, compared with that of a plane which is 100%, so
turbulence is no issue for a gyro.

Gordon Gao

Thanks for the warning Lutz, but I think if flown properly the gyro's
are as safe as the next aircraft.  Many people see the "open cockpit"
and can't imagine flying them.  This is because people don’t
understand them, and this is understandable as they are not as common
as their fixed wind counter parts.


Thanks,

Barron

There are 100's flying in the states and I'll bet the accident rate
is no higher than hang gliding. People don't fly them in
thunderstorms and they don't use them for getting from one place to
another. Strictly recreational.

You would not fly your hang glider in a thunderstorm would you?

Just put a tach on the rotor disc and an alarm :)

How people choose to kill them selves is nobodies biz but their own.
When is the last time a gyro crashed and killed some one on the
ground?

Government, get  out of my life and I don't want to pay them to do
it.

Paul Lamar



Hi!: by entering SAE.org  the store, and/or entering the search word
'autogyro' in the box at top right side of page, you can find some
technical papers about this flying machines, some from its inventor:
Juan de la Cierva, and others from people in the USA companies that
produced autogyros, and other engineers specializing in Aeronautics.
Is $24 downloading each paper, no need to be a member, and for the
articles that exist in SAE paper version as well as an article in
SAE Journal, the cost of downloading a full back issue is $14. By
digging in the Table of Contents of each issue, most are available
while others don't, you may find good reports on many issues
connected to engines and aircraft; as no major progress was done
since WWII in the field of reciprocating engine and propeller speed
range aerodynamics, many old articles still have a value, and the
goal is not outperforming of making out of date the NASA work.

Thanks for your attention, have a good week. Best regards. Salut †


Jose Gros-Aymerich

Madrid, Spain

The two biggest Autogyro problems are 1. They have a lot more drag
per lift than a fixed wing. 2.When you reduce the angle of attack of
the rotor disk too fast, the top drag reduces pitching the nose down
and can result in tumbling forward! Not survivable.

Dave James

Agreed, this is why it is important NOT to "HOTDOG" in an autogyro.

Thanks,

Barron



The auto gyro rotor speed is maintained by what is referred to as
rotor loading.  Rotor loading is a handy term that means that the air
is flowing up through the rotor.  The action of the rotor results in
a large drag against the flow of the air up through the rotor putting
a load on the rotor.

All is well during take off and climb phases of flight because the
rotor is tilted back relative to the airflow around the machine and
the engine thrust is set to a high value causing the whole craft to
pitch upward because the rotor drag is above the thrust line further
increasing the flow of air up through the rotor.

The problem comes when the throttle is reduced.  The pitching moment
of the engine thrust is reduced and thus the pitch attitude of the
whole craft is reduced.  This "unloads" the rotor causing it to
slow.

If the thrust is reduced suddenly, say by an engine failure, the
downward pitch of the craft can exceed the ability of the rotor drag
to prevent the pitch decreasing to the point where the air flow
through the rotor is reversed from up to down.

The same thing can happen if the pilot tilts the rotor forward too
quickly.

When the airflow through the rotor reverses the rotor almost
immediately slows to the point where the rotor blades begin to flap
due to lack of centripetal force to keep them straight.  The blades
usually come in contact with the propeller and/or tail structure
further slowing the rotor and damaging the rotor, propeller, and tail
structure.

At this point you're just a passenger on a rapid trip to whatever
solid surface may be below you.

A very similar thing happens with canard aircraft if the pilot
manipulates the controls such that the upward pitching rotation
exceeds the ability of the canard wing to arrest the upward pitch
rotation. The result is that the main wing stalls resulting in an
unrecoverable trip to the ground.  Auto gyro fatal pitch down, canard
fatal pitch up. Both ways you end up just as dead.

There are other ways to unload the rotor.  Let's say that the pilot
is flying at a low speed, usually close to the ground when
approaching a landing, when a gust from the rear, or sudden reduction
in wind speed from the front, reduces or reverses the airflow up
through the rotor causing the rotor rotation to slow.  Again, all
kinds of bad stuff ensues.

This happens often enough that they have a special name for it. It's
called "bunting over".  The result is invariably fatal.

There are very good reasons why the conventional, wings in the front
tail in the back, configuration is so common in successful flying
vehicles.

-- Mark LaPierre



Every aircraft has its lethal characteristics for which the pilot must be trained. Th biggest trap with the gyro is the experienced fixed wing pilot who "knows it all" , the controls seem conventional enough, but he must be trained to act in a manner to which he is unaccustomed in certain circumstances, particularly the ultralight pilot who has been trained to move the stitch forward smartly in an engine failure, thus unloading the rotor.
For a properly trained pilot I would contend that the gyro is by far the safest form of sport aviation. GOOD THOROUGH TRAINING IS ESSENTIAL
Most pilots have a lot to unlearn.

John Evans
Old gyro pilot


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