Why is Elevator Control so Heavy?

[MBDiagMan]

When I had my C, the controls in it were extremely easy in all axis.  While I still had it, I flew a friends F and when it was time to rotate I had to just tug hard on the yoke to get it off the runway.  It was quite a surprise.  I have flown a DC3 and it wasn’t as heavy on the pitch control?  Not long after I flew my friends F, I injured my shoulder and had to move to an Electric Gear plane.  I ended up with an electric gear F with all the J aerodynamic improvements and wonderfully equipped.  It took a while to debug it, but it’s now a wonderful airplane.  Ever since I took delivery of it, the stiff elevator control has been something to deal with.  Since my friends F was the same way, I have accepted that this must just be the nature of the beast.

Today, a good friend of mine who is a high time, lifelong professional pilot went with me to help with my landings.  He gave me some invaluable help and has me on the right track toward a better landing method.  In the course of this he commented about the heavy elevator.  To be clear, it takes pulling REAL hard to get it off the runway and I think it hinders control when trying to use finesse in the flair.

It’s as if there is something that needs to be lubed or is binding.  This isn’t normal is it?

Thanks in advance for whatever help you might can share.

[N201MKTurbo]

Set your trim a bit higher when you take off. That mark on the trim indicator is just a reference mark, not a hard requirement.

[MBDiagMan]

Thanks for the advice, but the control is stiff and binding even when the plane is on the ground, engine off.

[ShuRugal]

Thanks for the advice, but the control is stiff and binding even when the plane is on the ground, engine off.

Sounds like maintenance is required. Sliding bearings on the pushrods may be gummed up, or may be improperly positioned.

Sent from my Pixel 3a using Tapatalk

[PT20J]

Is it really stiff, or are you just feeling the effect of the trim assist bungees when you move the elevators on the ground?

Is it also heavy in the landing flare? If not, it sounds like the trim isn't set correctly for takeoff.

A quick way to tell if the trim indicator is properly set is to adjust the trim until the elevator is in trail with the stabilizer and note the trim indicator position.

Many find that starting the takeoff roll with about 5 lbs. of back pressure and proper trim allows the airplane to fly off when it's ready.

Mooney's don't have the lightest elevator forces, but I've also flown a DC-3 and it's control forces are heavier than any Mooney I've flown.

Skip

[ilovecornfields]

If it’s been that way since you bought the plane I would ask the person who did that annual if they noticed anything. If I recall correctly, it was from a shop that claims to be pretty good with Mooneys.

[N201MKTurbo]

3 hours ago, MBDiagMan said:

Thanks for the advice, but the control is stiff and binding even when the plane is on the ground, engine off.

Then I would lube the control system and make sure it is assembled correctly. There are rods in the tail that can be assembled wrong and will bind the elevator. Don’t neglect lubing the yoke shafts.

 

Bring it by and I’ll take a look at it.

[carusoam]

Cleaned and lubed… the yoke should operate smoothly…

As the year goes by, the lube goes away… and some stickiness appears along the range…..

 

Our ground stance (wheel leg height) keeps the nose pretty well planted past Vr…

A firm pull, raises the nose into flying attitude…

The same trim for T/O should work pretty well through the initial climb….

 

Use caution when increasing the trim… balance the unstick force with ease of setting off the stall horn….

Essentially the leg heights are giving a firm unstick requirement…

Once unstuck, relaxing the hold on the yoke let’s the trim setting do it’s thing…

 

PP thoughts only,

-a-

[Bartman]

Remove the belly pan and look for a screw that was too long and binding the elevator push pull tube. 

[Guest]

Check that the cup, item 13 is not too tight causing the phenolic ball item 12 to be seized in the cup.  I’ve also seen control column shafts with a slight bend causing it to bind in the ball.  Also look for anything behind the panel snagging on the controls.

Clarence

[Vance Harral]

I think what you're really asking here is, "what's normal"?  The replies to this are going to be model specific, because different models of Mooneys had different elevator pitch control systems: some have bungees, some have a counterweight, etc.  Concentrate on replies specifically from other F model owners.

In our 1976 M20F, the spring bungees incorporated into the pitch control system result in a stiff elevator feel, even when everything is properly assembled and lubricated.  With the trim set to the takeoff position, I would estimate it takes nearly 20 lbs of pressure to hold the yoke either fully back or fully forward against the stops.  That's the effect of the bungees.

When I fly the airplane with two passengers in the front seat, and set the trim indicator about 1/2 inch further up than the marked takeoff setting (a very reasonable choice with no weight in the back seats), I wind up pulling about 10 lbs of force on the control wheel to get the nosewheel to unstick.  Once the nose comes up, I relax that pressure, and the airplane climbs nicely at that trim setting.

So if you're experiencing around 10lbs of force from time to time, I'd call that normal.  If you're experiencing 20/30/more lbs of force, something is wrong.

[Guest]

You could also disconnect any one control joint separating the system in to two halves, and see if there is any resistance in the front or back half of the control system.

Clarence

[carusoam]

To get a feel for heavy elevators… try the Long Body.   

No bungees, the elevator hangs down when not moving….

You can feel the weight as you lift it…

If you drop it, it crashes what ever device you put on the yoke into the instrument panel….

 

The right feel sure is tough to describe….  
 

There is a design description for how much force is used to operate the controls…

Without calibrated arms… it is pretty hard to tell without using a scale….

If you have good memory, and you go to the gym often…  you can compare the force of one to the the other… 

 

-a-

[ArtVandelay]

The springs (bungees) make the J elevators control feel heavy except for small movements, it would be nice to use weaker springs. I had mine lubed and checked for binding.

[markgrue]

On the ground pull the yoke about halfway back and hold it.  Does it take more force to move it than to hold it?  If so it is a stiff linkage somewhere if not then you are just feeling the elevator bungees and it may be rigged improperly unless it just needs a trim adjustment.  Also look at the weight and balance.  Is it exceptionally heavy on the nose?  My airplane was heavy on the nose to the point that it could not be trimmed to hands off on a short field approach.  Weight was too much on the nose.  with 2 in the front seats and half fuel it was out of the cg forward limit.

 

Mark

[Ragsf15e]

I have an F.  Based on your description, I would say mine isn’t close to that heavy in pitch.  There are good suggestions here, especially from Skip and Doc.

[Bartman]

My elevator is heavy on takeoff if not trimmed up sufficiently. However, if it is trimmed up so that it flies off the runway I have to start trimming down very quickly after takeoff. It is best to trim such that I have to add some small amount of pull on the elevator with the takeoff roll and then relax after rotation, but still have to trim down a lot. The trim indicator is a little higher than the indicated takeoff mark, but I have gotten used to it. 

[Ragsf15e]

1 hour ago, Bartman said:

My elevator is heavy on takeoff if not trimmed up sufficiently. However, if it is trimmed up so that it flies off the runway I have to start trimming down very quickly after takeoff. It is best to trim such that I have to add some small amount of pull on the elevator with the takeoff roll and then relax after rotation, but still have to trim down a lot. The trim indicator is a little higher than the indicated takeoff mark, but I have gotten used to it. 

Sounds like not an issue for you, but adjusting where the trim indicates is a 2 minute job if you have the bottom panels off. It’s nice to know that the takeoff mark is pretty close.

[Hank]

23 minutes ago, Ragsf15e said:

Sounds like not an issue for you, but adjusting where the trim indicates is a 2 minute job if you have the bottom panels off. It’s nice to know that the takeoff mark is pretty close.

So do you set the takeoff mark for solo with half tanks, or two FAA+ people, or gross with rear CG? Cause all are different positions. 

The Owners Manual for my C says to pull hard to lift the nose then release some of the back pressure. What's in the Book for the F?

[Ragsf15e]

11 minutes ago, Hank said:

So do you set the takeoff mark for solo with half tanks, or two FAA+ people, or gross with rear CG? Cause all are different positions. 

The Owners Manual for my C says to pull hard to lift the nose then release some of the back pressure. What's in the Book for the F?

Not sure what it says for rotation but I use the common technique about holding back about 5lbs pressure during the roll.  With the trim set on TO, the weight doesn’t seem to make much difference unless there’s two large folks in the front and no baggage.  I just like having a known position for the trim before takeoff.

[Bartman]

For my usual mission of me and the wife, full fuel and luggage at or near max gross 2,740 lbs I set the bottom of the movable indicator bar at the top of the fixed reference mark and it’s not worth trying to adjust it. If it’s me and an instructor or passenger I set it the same and adjust with pull on the yoke. The biggest issue at the home airport is bumps at 1,000 feet on both ends which can launch you before she is ready to fly.  

[Browncbr1]

The TO trim marking is ok if there are people in the back seat and luggage.  If it’s just me or two up front, I trim at the top or a half dot above the upper marking, but it requires lots of down trim as I speed after lift off.  

[MBDiagMan]

On 1/22/2022 at 1:18 PM, PT20J said:

Is it really stiff, or are you just feeling the effect of the trim assist bungees when you move the elevators on the ground?

Is it also heavy in the landing flare? If not, it sounds like the trim isn't set correctly for takeoff.

A quick way to tell if the trim indicator is properly set is to adjust the trim until the elevator is in trail with the stabilizer and note the trim indicator position.

Many find that starting the takeoff roll with about 5 lbs. of back pressure and proper trim allows the airplane to fly off when it's ready.

Mooney's don't have the lightest elevator forces, but I've also flown a DC-3 and it's control forces are heavier than any Mooney I've flown.

Skip

Yes, it is heavy in the flare.

[MBDiagMan]

On 1/22/2022 at 1:30 PM, ilovecornfields said:

If it’s been that way since you bought the plane I would ask the person who did that annual if they noticed anything. If I recall correctly, it was from a shop that claims to be pretty good with Mooneys.

Yes, the shop does make that claim and it has been this way since I bought it.

[Bartman]

27 minutes ago, MBDiagMan said:

Yes, it is heavy in the flare.

I continue to trim in the flare all the way to eventual stall and when I do touch down there is very little back pressure on the yoke.  After landing I have to trim down quite a bit to get back to takeoff settings.