Wow, now that's depressing...im really sorry, sadly with Wright Stuff gone next year you won't get a chance at redemption....That was the first time it had ever happened...I repaired the plane in less than a minute, but then the next 2 rubber bands snapped at low torque. I only got off that first flight, which lasted less than eighteen seconds, as compared to my consistent four minutes. It's okay though, because I won every other competition I entered, even against JC Booth at Solon, my biggest moment of pride. I wound up in 54th at nats.
And helicopter could never take Wright Stuff's place...
Edit: Btw, how do u get a plane to move so slowly? I don't really understand the physics in this event, but it's really cool.
Here are replies to the questions posed above, mamley, "How is stab twist/stick bending caused? High torque?"
The prop hanger and the rear motor hook place the wound rubber motor below the motor stick, causing it to bow. This is because the rubber motor pulls on each end of the motor stick similar to the forces exerted by a bow string when a bow and arrow are used to shoot an arrow. The bowing on the motor stick is very difficult to see, but since the tail boom extends many inches from the end of the motor stick the effect is accentuated, often resulting in positive stab incidence when you usually want about one degree of negative stab incidence.
The higher the torque, the more the bending, depending on the stiffness of the motor stick. The amount of bending of a solid motor stick depends on the nature of the wood, mostly the lbs per square foot and the cross - sectional area. Solid motor sticks should be carefully selected by weighing them individually and testing them on a stiffness measuring device. A couple of dowel pins inserted in vertically extending planar piece of hardwood will suffice to hold the inner end of the motor stick. A weight can then be hung on the free end of the motor stick and the deflection measured using graduated markings on the surface of the hardwood.
The same rubber motor torque temporarily causes the motor stick to twist around its longitudnal axis, causing the stab tilt to disappear or even go in the opposite direction to that desired. This can cause your plane to fly in a wide circle at launch, instead of the smaller circle desired, and can result in the plane hitting the wall.
Motor stick twisting can also tempmorarily remove wash - in, i.e. the designed - in lower trailing edge on the inboard side of the main wing. The motor stick twists between the main wing posts, causing them to change their relative angles and inducing an undesired warp in the main wing. Removal of the wash - in could cause the plane to spiral into the floor at launch.
Rolled motor sticks are less suspetible to undesirable motor stick bending and twisting. However they require considerable time and skill to build properly.
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