Mooney Vertical Stabilizer

[201er]

Ok, so what's the deal with the Monoey vertical stabilizer? What's the thinking behind it?

Here's my theory. By having the leading edge vertical and the trailing edge tapered, it actually provides more rudder authority with a lower forward facing drag profile. I think if you'd measure the leading edge of the Mooney vertical stabilizer compared to that of other planes, it would come out noticeably less. The slanted ones have to add surface area for all the extra surface from being slanted. Think hyoptenuse. Yet the Mooney enjoys a bigger rudder this way because the slant on the rudder provides more surface area (tall) rather than having a deeper rudder which makes more drag in the turns. What do you think?

[Txbyker]

Rudder is verticle in climb, more efficient?

[yvesg]

One thing I noticed when moving to Mooney from Cessna 172 is the difference in yaw axis stability. The Cessna is more stable, less need to use the rudder (asnd specificall during descent). I always thought this was due to the surface difference between the two.

Yves

C-FQKM

[FloridaMan]

I read somewhere that the profile was to provide greater authority at higher angles of attack. I'm thinking it may be so you can still have a larger rudder with less forward profile (as you said), and, at the same time, reduce the amount of force placed on the rudder at full deflection. I'm wondering if the technical aspects of the flying tail could have something to do with it as well.

If you look at the profile of aerobatic aircraft rudders, you'll notice that they have more surface area near the elevator. I understand this as being there to compensate for the airflow interruption from the elevator.

[fantom]

Over analyzing it, guys.....it's to be different, and look cool.

[Hank]

I always heard that the rudder slants forward so that it is approximately vertical in the landing configuration, to improve low speed / high-alpha control. Making the stabilizer straight up was just a cool option rather than having both slant in like on the pretty aerobatic bird above.

Aircraft with the entire stabilizer/rudder combo slanting backward give up some rudder authority during landing. Slant the rudder backwards, then raise the nose, the rudder is at a pretty good angle to the relative wind; our rudders are almost perpendicular to the relative wind.

[carusoam]

I'm with Gary on this one. It Looks cool, and works fairly well...

Al Mooney had a sense of humor when building planes. In 66, he increased the surface area of the rudder, because it was too small.

Look back to the 60s for vertical tales on B and C types. In the 70s everyone was mimicking the 'jet age'... Mooney installed the butler button hook and stinger on the tail to really go along with the style...

Fortunately the J and later were designed using aerodynamics as the guideline... Customers like that better...

My take on aviation history anyway...

Best regards,

-a-

[fantom]

I'm with Gary on this one. It Looks cool, and works fairly well...

....and it's what Roy LoPresti told me!

[OR75]

more s..y look on the ramp ...

[jlunseth]

Well, I hate to break it to you but about the only place where the tail is vertical is sitting on the ramp after you have trimmed up for landing, and while you are trimmed up for takeoff. The rest of the time the tail angles back along with the rest of the rear empennage that articulates about the bolt that holds in onto the airplane. It can look a little like a Cherokee.

[N201MKTurbo]

The rudder, horizontal stabilizer and wing have straight leading edges because it is the cheapest and easiest shape to assemble, wrapping a piece of sheet metal around anything other than a straight edge wastes material. Read Al Mooney’s book, it wasn’t done for any particular aerodynamic reason.

[Jerry 5TJ]

Somewhere in the Al Mooney lore is the claim that the distinctive Mooney tail was designed to roll better...hmmm, it looks like the tail on the Extra, with the maximum rudder area nearest the longitudinal axis of the plane, doesn't it?

[RobertE]

I haven't read Al Mooney's book but I'd make a big, big bet the rudder is as it is for one reason - it was cheaper to produce in small volumes. The rudder and elevators are built, I think, in the same jig. They have an identical cross-section. If you were starting a company, had no idea how many units you were going to sell but knew you could save money and produce a distinctive shape at the same time, what would you do?

[201er]

I haven't read Al Mooney's book but I'd make a big, big bet the rudder is as it is for one reason - it was cheaper to produce in small volumes. The rudder and elevators are built, I think, in the same jig. They have an identical cross-section. If you were starting a company, had no idea how many units you were going to sell but knew you could save money and produce a distinctive shape at the same time, what would you do?

This is an interesting theory, plausible, and possibly true. But... why don't we see this on more airplanes then!? I would guess the 172 (cheap trainers) or other low volume planes would have this. If your theory is true, then I would expect this tail type to be the norm and the fancy bent tail to be the rarity.

[fantom]

The rudder and elevators are built, I think, in the same jig. They have an identical cross-section.

From the many times I've been through the factory, I know the above is factual.

[PTK]

The theory is that the vertical tail positions the rudder so as to maximize its effectiveness when really needed, such as in nose high attitudes.

But when you actually look at the entire empennage as a whole, and consider that the pitch trim control moves the entire empennage, it becomes evident that you want the tail to be vertical!The vertical position of the tail actually minimizes the stress on the pitching mechanism. By sitting vertical its center of gravity is perpendicular, thus eliminating unwanted or unfavorable cantilever forces. These forces would greatly stress the pitch trim control mechanism probably making it impossible to have the all pitching tail design.

Some other less known aircraft utilize similar design elements of the all pitching empennage...Boeing 777 & 747!

Mooney...simply brilliant!!

[jetdriven]

The 747 and 777 (and most other jet transports) have only an all-moving stabilator, but AFAIK the Lockheed JetStar is the only other airplane with a completely pivoting tail, designed by Al Mooney, of course.

our tail might be backwards, but none ever fell off. Of course, Beech fixed their V-tail thing in the 80s, and none have failed since then. They look pretty cool too.

[Marauder]

I always heard that the rudder slants forward so that it is approximately vertical in the landing configuration, to improve low speed / high-alpha control. Making the stabilizer straight up was just a cool option rather than having both slant in like on the pretty aerobatic bird above.

Aircraft with the entire stabilizer/rudder combo slanting backward give up some rudder authority during landing. Slant the rudder backwards, then raise the nose, the rudder is at a pretty good angle to the relative wind; our rudders are almost perpendicular to the relative wind.

And I always thought mine was installed backwards!

[BigTex]

This is one many things I love about Mooney's. These planes are so cool at many levels. I consider them to be the Mac's of aviation. They have soul.

[Marauder]

This is one many things I love about Mooney's. These planes are so cool at many levels. I consider them to be the Mac's of aviation. They have soul.

Amen brother! I'm with you!

[201er]

I consider them to be the Mac's of aviation. They have soul.

Please, don't make me puke

[Marauder]

Please, don't make me puke

Puke away young gun...

[RobertE]

This is an interesting theory, plausible, and possibly true. But... why don't we see this on more airplanes then!? I would guess the 172 (cheap trainers) or other low volume planes would have this. If your theory is true, then I would expect this tail type to be the norm and the fancy bent tail to be the rarity.

Again, I haven't read Al Mooney's book nor been to the factory. I'm just piecing things together. But a reason not to do what Al seems to have done is that it means you're forced to have a symmetrical horizontal stabilizer rather than one that produces downward lift. And carrying that a bit further, might that have led to Al deciding to move the entire tail assembly to achieve trim? Otherwise, the elevator would have to be deflected pretty significantly at the upper or lower ends of the speed range to maintain trim.

[KSMooniac]

Most light planes have symmetrical airfoils on the horizontal tail, believe it or not. I would think that would be a great area to optimize with a more effective/lower drag airfoil but I guess there are compelling reasons not to do it.

Al Mooney did indeed maximize simplicity (and thus minimize cost) with the empennage design thru the straight leading edges and symmetrical sections. The all-moving empennage to accomplish trim is extremely efficient in structure (and cost) while it minimizes drag and complexity associated with a conventional trim tab and the greater deflections of the elevators for any given flight condition compared to what we have on the M20. Extremely elegant in this aero engineer's opinion! There are a lot of well thought-out details throughout the M20 airframe.

[FloridaMan]

Most light planes have symmetrical airfoils on the horizontal tail, believe it or not. I would think that would be a great area to optimize with a more effective/lower drag airfoil but I guess there are compelling reasons not to do it.

Al Mooney did indeed maximize simplicity (and thus minimize cost) with the empennage design thru the straight leading edges and symmetrical sections. The all-moving empennage to accomplish trim is extremely efficient in structure (and cost) while it minimizes drag and complexity associated with a conventional trim tab and the greater deflections of the elevators for any given flight condition compared to what we have on the M20. Extremely elegant in this aero engineer's opinion! There are a lot of well thought-out details throughout the M20 airframe.

Might be a little unrelated, but I'm under the impression that some newer designs, such as the DA-20 have their horizontal stabilizer canted slightly to counter-balance some of the effects created by the prop/engine.