Mooney Aerodynamics

[PT20J]

Just now, 0TreeLemur said:

Skip I"m curious- do the ailerons on the J extend all the way to the wingtip as they do on the C?  The interaction between the aileron end and the tip vortex add to heaviness in roll.   The later models of M20 put 10" of wing outside the aileron to detach it from the tip vortex.  If the J has that then that will be a factor too.

The original J was the same as the F with ailerons going all the way to the tips. I think it was around 1981 that the plastic wing tips and enclosed balance weight were incorporated. The other thing that doesn't help is the chord. It takes a certain area to get the effectiveness desired. A lot of span got used for the flaps so that makes it necessary to increase chord to get the required area. I believe that the hinge moment varies linearly with span and as the square of the chord.

Skip

[Fry]

Aerodynamics question: What's the purpose of the two horizontal pieces of sheet metal riveted to the vertical stabilizer?

I'm sorry if this has been asked before.

[Blue on Top]

1 hour ago, Fry said:

Aerodynamics question: What's the purpose of the two horizontal pieces of sheet metal riveted to the vertical stabilizer?

@Fry  The two pieces of "sheet metal" are the VOR/Localizer antennas.  On some airplanes, they have an added/bonus benefit of slowing vertical airflow on the vertical stabilizer.  This is not the case on Mooney aircraft, which do not have that vertically upward flow (because the vertical surface is forward swept).  I think you might be referencing Don Maxwell's photo on Facebook this morning.  The only dumb question is the one that is not asked.  Hope this helps.  

[Fry]

Thanks. I really did not know this, although the VOR antennas e.g. with Cessnas are typically located at the same place (however look like two wires arranged in a V shape).

Every day something new...

PS. I do not have a Facebook account. What did Don Maxwell post?

Edited June 15, 2020 by Fry

[Blue on Top]

4 hours ago, Fry said:

Thanks. I really did not know this, although the VOR antennas e.g. with Cessnas are typically located at the same place (however look like two wires arranged in a V shape).

Every day something new...

PS. I do not have a Facebook account. What did Don Maxwell post?

@Fry  Here is what Don Maxwell posted on Facebook (I added the red arrow):

There are 3 common shapes of VOR/Localizer antennas: the blade (pictured), wires in a "V" shape (as you mentioned) and what people call "towel bar" antennas.  The "towel bars" are roughly the same external/outside dimensions as the blades but look like a 1/2" rod bent in a rectangular, "U" shape …. like a towel bar for a wash cloth.  Hope this helps!

PS. Forgot to mention that the lowest drag of the 3 is the two wires in a "V".  This is counter-intuitive as most people (including me … an aerodynamicist) would think that the blades are the lowest drag.  The blades have more surface area (drag) and are more sensitive to local angle of attack.  Bonus info  

Edited June 15, 2020 by Blue on Top