Flight Dynamics ofthe TurboPlaneWhile reading this description remember that any force applied to the aircraft will have an output 90 degrees perpendicular to the input.It is also helpful to realize that a small amount lift is created on the disk in hover mode. A kind of injector system is at work. High velocity air blown downward through the center hole of the disk creates a low-pressure area on the upper surface of the ring wing. High velocity air will travel across the upper surface of the ring wing creating lift via the Coanda effect. The high velocity air blown downward through the center hole will create most of the lift but the lift created by the Coanda effect will help stabilize the craft by spreading the lift over a large area. A kind of circular vortex of air flows across, inward, and downward on top of the ring wing. This should slow down control inputs and make reaction times longer. Additionally the ring wing is spinning at a modest speed, which will increase the Coanda effect. I sat down with a plastic top from a yogurt container and was able to visualize the torque reactions created by the combination of the engine and the ring wing. It was easy if you hold the plastic disk up in front of your face like a bicycle wheel. Turn the disk like a wheel rolling away from you. If you lean the top of the disk left the disk would turn left just like riding a bike and conversely if you lean the top of the disk right the disk will turn right. Now you have a reference on how to visualize the rest of the action / reactions created when a force is applied to the disk. Assume that the engine turns cc and the ring wing turns cc will viewing from above. Assume that the whole device is stabilized in hover and forward flight mode by the gyroscopic action of the ring wing and propeller. Assume that the whole device is support by a combination of lift from the top of the Ring Wing and mostly from the thrust created by the Propeller. Since the entire device is hanging from the single plane or you could say localized point (top or the RW and Prop) you can see that the majority of the mass of the device hang like a pendulum from this point. It is pendulum force that makes the TurboPlan so stable in hover. The device will always hangs perfectly level with respect to the earth’s center. Thus achieving a stable hover. This pendulum force returns the device to level hover when the pitch flap is retracted. The whole device is strongly influenced by engine torque/ring wing torque, similar to a tail dragger taking off. It wants to turn left with the application of power, and to a lesser degree turn right with a reduction in power. The Turbo Plane likes to do every thing to the left. Turns to the right required much more rudder control input. Every control input affects the disk at a 90-degree output. Thus it climbs when turning left and dives when turning right. It should be much easier to land going in right-hand descending turns. The craft will respond more slowly and tip the disk down automatically for decent with a reduction in power. If he elevator (flap) is not deployed the rudder only turns the pod on axis. If the flap is deployed then the rudder will be able to steer the disk and affect a turn. On a sideline, when the flap is deployed the disk will turn left; when the flap is retracted the disk will turn right. Not much but some. Deploying the flap will allow the craft to accelerate on a heading, to hold the heading some or (maybe a lot) of rh rudder is required to offset the engine/ring wing (rw) torque. To turn right slowly: Deploy the flap and add rh rudder and wait. To turn right fast: Deploy the flap, add full rudder and reduce power. To turn left slowly: Deploy the flap and add a small amount of left rudder. To turn left fast: Deploy the flap, add a modest amount of left rudder and add power. Retracting the flap cause a small turn to the right, and the disk will return to level and forward speed will bleed off. It is returned to level by the pendulum force. Max ground speed is reached with complete deployment of the flap and full throttle. This device is stable because there is a force to balance all opposite forces. But it really likes to turn left. This is a function of the constant torque applied by the engine and the ring wing being driven by the prop blast. In fact if you look closely you will see some similarities to an automotive torque converter. It has stators, and vanes and uses a fluid to couple the engine to the drive train. The Turbo Plane has some of these features and uses air as the coupling fluid. Kelly McCombs Eugene Oregon USA August 6, 2004 kelly@obie.com |