Elevator position in relaxed on ground parked!

[RocketAviator]

Had a guy come out to the ramp where I have a second home and he had just seen a couple other Mooneys fly formation with me who had a question for me!

Why does your Mooney elevator relax to the full down position and mine does not he ask?

He has a 69E

I had no idea and had never paid any attention to elevator position in relaxed condition. Looking at several pictures what I found online of other E & they appeared to have the elevator in slightly down relaxed position.

I see in another forum some topic about elevator rigging setup by serial #.

[N201MKTurbo]

The 231 has a bob weight in elevator system. The E does not.

[Piloto]

I used to have a M20C model with the elevator spring but not on the M20J model I have now. I think the spring is for flutter prevention which later on they opted for weights. The spring may cause an elevator/stabilator divergent condition that could cause added drag thus lower speed. 

 

José

[Hank]

Every Mooney I've ever seen up through J parks with elevators level. K, M & S drop to Full Down; don't remember what Rs do, and I've never seen a TN in person. (Let me know, Joe, if you're ever in the area . . . )

When I asked the K owner in some surprise about it, his answer was much like yours, along the lines of "I dunno, I never noticed."

So now we know, floppy tails they have weights in them. What does it accomplish?

[cliffy]

Any Mooney with spring bungees on the elevator is rigged to a certain amount of UP elevator at a specified stabilizer setting. You can read what it is by model on the TCDS sheet. The actual angle observed, at rest, will vary with whatever stab (elevator trim setting) setting the airplane landed or parked with. 

Per Bill Wheat (when I asked him last summer), Al Mooney used bungees to help provide the correct amount of elevator force required by design specs while keeping the tail surfaces as small as possible to reduce drag. He said they allowed him to use surfaces 25% or more smaller than similar airplanes and still have the require control authority. 

Later models did away with the bungees. 

[N201MKTurbo]

The bob weight counteracts the aerodynamic forces on the elevator and and adds stability by making a down pitching force when g loads are applied.

[EDNR-Cruiser]

With my 66 F model it's a question of trimming. If I leave the trim wheel in full nose up position as for landing, my elevator will even be in the up position at the ramp... - which looks quite stupid. Therefore I trim my M20F nose heavy for parking, causing the elevator to relax in the full down position. 
The yoke moves in sync with the elevator position and it's easier to enter or leave the plane with the yoke in full forward position than in the full aft position.

[carusoam]

The O's elevator is a bit heavy.

It is most noticeable to the pilot when checking the flight controls. Any GPS on the yoke will make contact with the panel unless some back pressure is applied....

To balance the force required, just add throttle...

[Andy95W]

Any Mooney with spring bungees on the elevator is rigged to a certain amount of UP elevator at a specified stabilizer setting. You can read what it is by model on the TCDS sheet. The actual angle observed, at rest, will vary with whatever stab (elevator trim setting) setting the airplane landed or parked with. 

Per Bill Wheat (when I asked him last summer), Al Mooney used bungees to help provide the correct amount of elevator force required by design specs while keeping the tail surfaces as small as possible to reduce drag. He said they allowed him to use surfaces 25% or more smaller than similar airplanes and still have the require control authority. 

Later models did away with the bungees.

Excellent explanation and description. Thanks, Cliffy.

[1964-M20E]

With my 66 F model it's a question of trimming. If I leave the trim wheel in full nose up position as for landing, my elevator will even be in the up position at the ramp... - which looks quite stupid. Therefore I trim my M20F nose heavy for parking, causing the elevator to relax in the full down position. 

The yoke moves in sync with the elevator position and it's easier to enter or leave the plane with the yoke in full forward position than in the full aft position.

+1

[Awqward]

As an aside, I use a spring loaded control wheel lock which connects between the yoke and the rudder pedals...thus the elevator is in the full down position when parked.....I think this is better than passing a seatbelt through the yoke and having the elevators in the up position because of the drain holes which are on the trailing edge....leaving them causes them to fill with rain water leading to corrosion...

[Hank]

I run a bungee between the yokes. Clip on one, round the other, back to the first and clip again. Seems to restrain the elevator and the ailerons. Done after I exit the plane, it does not affect elevator position,  just keeps it where it is.

 

Similarly, I've never seen my trim position affect elevator position, it tilts the whole blooming tail and will change horizontal stabilizer position.

[John Pleisse]

The bob weight counteracts the aerodynamic forces on the elevator and and adds stability by making a down pitching force when g loads are applied.

 

I thought the bob was a counter weight for the larger 231 engine? This is only for the 231's and 252's right? The long bodies are neutral as well because the fuselage is stretched, right? All Mooneys except the 231-252 should be neutral with only a small droop?

[N201MKTurbo]

The bob weight replaces the spring bungees. The big difference is that the bob weight responds to g loads and the spring bungees don't.

 

The bob weight adds stability, the down side is it adds weight. With the 231 they needed some weight in the tail to balance the heaver engine so they had nothing to loose.

 

 

 

 

 

 

[RobertGary1]

I often run the trim full forward to make it easier for pax to get out without getting caught on the yoke.