Hi.
This appears to be a Giro newcomer and newcomers need guidance?
In the past Model Aviation ran an introduction story on Autogyros. Responce to that by interested modelers was unblieveable. Question from majority was how does the rotor work? Good question, if you are to use something you would do
well to understand it's workings, right?
An Autogiro rotor self rotates, in the process lift is created.
A windmill's "blades" are vanes, basically flat. An Autogiro's blades are airfoils, wings. Thus the lift is created by rotating wings
and must be thought of as such
As with an airplane moving wings create lift, with a Gyro the
wing movement is rotation.
What creates rotation?>>>Two factors are used, first the rotor is arranged similiar to a windmill and as such the airstream striking it causes it to rotate. Rotation increases until rotor drag equals the airstream force.
Remember Giro blades are airfoils and that an airfoil always lifts
vertical to the line of flight. Knowing this the rotor is arranged so
that the vertical lift produced also has a forward force vector. This
forward vector tends to pull the airfoil, thus increase rotation.
Know that lift increases as a square of the air speed, rotation speed Giro-wise.
Thus as the windmill action increases rotation speed lift is increasing as a square of the speed. Thus as the windmill force
reachs it's maximum that forward lift vector has increased dramatically, this is labeled "autorotation" and it takes over the
rotation accelerating it until drag creates a limit
Happily for the Autogyro once airborne with the rotor autorotating forward speed is not required. it can be halted in a
hover and the rotor will still maintain it's RPM and lift
This explaination is neceesarly brief. Should say a report in depth and detail is scheduled for a coming issue of R/C Report magazine. Publication date? Ask editor Gordon Banks at E-Mail ([email protected])