How do you feel about the Mooney tail?

[PT20J]

The thing I like best about the Mooney tail is that when people unfamiliar with airplanes ask how they will recognize us when we arrive, I just tell them we’ll be in the plane with the tail on backwards. Works every time. 

Skip

[Blue on Top]

On 4/25/2022 at 5:21 PM, PT20J said:

I believe there are two aerodynamic advantages to the forward-swept vertical stabilizer. First, the stabilizer will be more effective if all the airflow is normal to the quarter chord line as any spanwise flow component is not beneficial for generating an aerodynamic force. The most critical situation would be at low speeds where the dynamic pressure is lowest. At the higher deck angles for lower speed flight, the forward sweep will put the quarter chord line more perpendicular to the relative wind. This allows a smaller tail. The second advantage is that any spanwise flow will be away from the tip which will reduce the tip vortex and drag. This would be more important in cruise flight. I'm still learning and perhaps Ron @Blue on Top will come along and correct me if need be.

Skip

@PT20J nails it again! Sweep is defined at 25% chord. As aircraft AOA increases, the vertical stabilizer/rudder 25% chord gets closer to being perpendicular to the local airflow, making it more effective. In addition, the Mooney rudder effectiveness is greatly increased by the forward sweep of the hinge line. It's going to get a little technical here, but ...  all y'all will get it. In other words (and when looking at the pressure side of the vertical/rudder (the side the rudder is deflected toward), the local airflow wants to go DOWN the hinge line, but it can't because the pressures are higher there (larger chord). As a result, the flow goes straighter, back over/around/across the rudder. This makes the rudder more effective. Note: the flow also can't easily go UP the hinge line because that is forward (against the main airflow).  

Someone also mentioned control effectiveness with airspeed. The ailerons should stay more effective than the tail surfaces because the dynamic pressure (airspeed, Qc, etc.) over the ailerons remains close to the airspeed indicator. The tail surfaces on the other hand are seeing lower dynamic pressure (airspeed, Qc, etc.) because the wing, flaps and propeller are slowing it down. FYI, this is why Mooney aircraft have a down spring (low speed, longitudinal stability).

Additional FYI, the rudder-aileron interconnect doesn't know (change with) airspeed. In this case, force is force ... not dynamic pressure (airspeed, Qc, etc.) dependent.

PS. Hoping to have some really, freaking cool video for Oshkosh!