Item 0111
DESIGN: SynchroLite ~
Fuselage - Tail - Stabilator Layout
Drawing:
Notes:
In hover the stabilator will present a larger area to the rotors downwash.
-but-
In forward flight the downwash will have a higher airspeed.
In hover the relative airflow will be at an angle of + 90 degrees (approx.)
In forward flight at 55 knots the relative airflow will be at an angle of + 11.5 degrees (approx.)
In autorotation the relative airflow will be at an angle of - 12.5 degrees (approx.)
In respect to the longitudinal axis (X) by having most of the torque located below the axis there will be a tendency to center the stabilator.
Make sure that application of yaw will not introduce roll; caused by unequal forces about X-axis. Perhaps the two airfoils could have a bend, making a very shallow 'W' when viewed along the X-axis.
A rudder, located aft of the disk and as high as possible, will still be required.
Basic assumptions re operation
The stabilator is level and inline with the centerline of the tailboom.
The tailboom is at an angle of 12ºs.
The stabilator is therefore at an angle of 12º to the tailboom. Angle of incidence = 0º.
|
Airflow |
Roll of stabilator (CCW) |
|
|
0º |
22.5º |
45º |
90º |
|
+90 º |
0º |
CCW |
CCW max. |
0º |
|
+12 º |
0º |
CCW max. |
0º |
CW |
|
-12 º * |
0º |
CCW |
CCW |
CCW max. |
Want CCW yaw.
* Stabilator pitched approximately 24+ degrees down.
This change in the angle of incidence should probable take place at a slower rate than the lowering of the collective. Its change should probably be related closely to the craft's change in vertical velocity through the air
I THINK. The yaw switches direction when the plane of the airfoil passes through the line of the airflow. In autorotation this can never happen.
Since the yaw tube rotates a maximum of 14.5 degrees make the ratio between the yaw tube in the tube and the yaw tube in the boom 1.5:1 ratio planetary gearing in plastic. This gives a maximum rotation or 21.75 degrees.
Idea: Could have opposite direction one at front, also.
From 'Gyroplane Stability' Article by Chuck Beaty on Horizontal Stabilizer Sizing:
" NACA investigated the problem and concluded that a horizontal stabilizer volume equal to 10% of the rotor volume would provide a solution. Modern helicopters generally follow this rule.
Rotor volume = Rotor blade area * Rotor diameter
Horizontal stabilizer volume = Horizontal stabilizer area * Moment arm length"
Introduction Page | Electrotor Home Page | SynchroLite Home Page | UniCopter Home Page | Nemesis Home Page
Last Revised: November 30, 2007