A Vexing Question on Tail Angles

[Jeff_S]

Hey all,

I'm hoping y'all can help me solve a question that I've had recently. It has to do with the characteristic shape and look of the Mooney tail.  I've always associated the Mooney with a vertical stab that goes straight up from the empennage and then straight back, for a nice square look.

But lately I've seen photos, especially of some later-model Acclaims and such (see Andy Smith's gallery: http://www.mooneyspace.com/index.cfm?action=gallery&userGallery=388) where it looks as though the angle of the stab and top are tilted slightly backward. I could swear I've even seen this on some J model pics as well.

So, is this just an optical illusion, or maybe the result of the the plane being in a tail-down attitude? Or was this a slight design change at some point? I know, it's probably a silly question but I'm curious.

Jeff

[MooneyMitch]

Hi Jeff.

The angle of the "straight up" leading edge of the Mooney tail changes, depending on trim setting.   As we rotate the trim setting wheel for up or down trim, the entire empannage moves forward or backward respectively, thereby changing the angle of that straight up looking tail. 

Depending on where the pilot leaves the trim setting after flight, does affect the sight picture of the tail.  Hope that helps. 

 

[Jeff_S]

D'oh! Of course that's the answer. I hadn't factored in how trim changes the whole attitude of the tail section, and in cruise flight it will be angled backward to reduce downward force from the elevator. Makes perfect sense...thanks!

[MooneyMitch]

For me, I do like that straight up look when the plane is on the ground, but...............I usually set the tail and rudder trim for the takeoff postion before shutdown.  Just my little Rod Machado "so what" factor.   

[Hank]

After landing, my trim is often very near where I position it for takeoff. Light, touching the top of the "Takeoff" mark; heavy, lined up properly. But then again, I rarely make full-flap landings.

[jlunseth]

I have an item on my checklist to return the trim to takeoff position after landing, so my tail is always in the correct Mooney-looking position when the plane sits on the ramp.  Wouldn't want someone to mistake it for a Cherokee or such like.

[MooneyMitch]

Quote: jlunseth

I have an item on my checklist to return the trim to takeoff position after landing, so my tail is always in the correct Mooney-looking position when the plane sits on the ramp.  Wouldn't want someone to mistake it for a Cherokee or such like.

[carusoam]

Take a look at how much the tail sweep actually is.  Anyone with the ADF wire still on the tail will recognize the length of the spring required to adsorb all of the tail motion.  In some cases with the trim all the way up the ADF wire is laying on the roof of the fuselage.

Don't let anyone tighten your ADF wire while the trim is in the up position.  It leads to a huge surprise after take-off.

Best regards,

-a-

[Jeff_S]

Quote: jlunseth

I have an item on my checklist to return the trim to takeoff position after landing, so my tail is always in the correct Mooney-looking position when the plane sits on the ramp.  Wouldn't want someone to mistake it for a Cherokee or such like.