Elevators not lined up.

[Guest]

1 hour ago, Shadrach said:

Odd, it’s been in the family since new. Never been repainted. Tail has never been damaged nor removed. Don’t recall a thing in the logs about adjusting the elevators. I’ll see about adjusting it at annual.

I’m willing to bet that at some point in its life it’s had a rod end bearing in the tail section replaced, and a mis adjustment crept in.  The aft rod end at the elevator is adjustable so it’s easy to correct and match them again.

Clarence 

[Shadrach]

3 minutes ago, M20Doc said:

I’m willing to bet that at some point in its life it’s had a rod end bearing in the tail section replaced, and a mis adjustment crept in.  The aft rod end at the elevator is adjustable so it’s easy to correct and match them again.

Clarence 

Thanks Clarence. I’ll look for an unpainted rod end. It only has 3300TT so it’s now getting to a place where some rod ends are getting sloppy.

[Guest]

15 minutes ago, Shadrach said:

Thanks Clarence. I’ll look for an unpainted rod end. It only has 3300TT so it’s now getting to a place where some rod ends are getting sloppy.

It would have to be in the tail section, where the left and right push rods conned to the single push rod.

[Shadrach]

10 minutes ago, M20Doc said:

It would have to be in the tail section, where the left and right push rods conned to the single push rod.

I’ll look at them tomorrow tomorrow with a mirror. I think the bungees obscure a visual inspection. Is it simply a matter of loosing the nuts on the rod ends and turning the tube? I’m going to defer until annual but want to know what we’re getting into.

[Fly Boomer]

20 hours ago, Shadrach said:

My bird is upper end of speed for an M20F (150+KTAS)

Lots of rigging analysis above.  If I was at the top end for my model, I would leave it.

[EricJ]

20 minutes ago, Shadrach said:

I’ll look at them tomorrow tomorrow with a mirror. I think the bungees obscure a visual inspection. Is it simply a matter of loosing the nuts on the rod ends and turning the tube? I’m going to defer until annual but want to know what we’re getting into.

There are four rod ends, the two at the front and the two at the rear (50 and 52 in the diagram Clarence posted).   The rear ones can't be turned unless disconnected from the control surface.   The front ones are accessible through the inspection plates and the hinge joint covers under the stabilizer, to check for play there.   It could be that one of the front rod ends was swapped out as well, or the misadjustment happened there.

[Shadrach]

6 minutes ago, Fly Boomer said:

Lots of rigging analysis above.  If I was at the top end for my model, I would leave it.

There is wisdom in what you say for sure. However, there is no way that Mooney was doing a detailed rigging in 1967 when the factory was pumping out >3 planes a day. My guess is that “good enough” was the target. I theorize that my bird is on the upper end of the speed spectrum because it was a factory dealer demonstrator, or rather it was chosen for such a role for that reason.  There are a few folks here that have coaxed genuinely impressive speed gains out of already above average flying airframes but it takes time and attention. A task I might be up for.

[Shadrach]

2 hours ago, EricJ said:

There are four rod ends, the two at the front and the two at the rear (50 and 52 in the diagram Clarence posted).   The rear ones can't be turned unless disconnected from the control surface.   The front ones are accessible through the inspection plates and the hinge joint covers under the stabilizer, to check for play there.   It could be that one of the front rod ends was swapped out as well, or the misadjustment happened there.

I don’t think any of the rod ends can be turned unless disconnected. I was assuming the jam nuts for each rod end could be loosened and the tube turned to adjust length. Is this not the case?

Surprisingly there is almost no play from one side to the other. Someone with no knowledge of geometry might think they were a single unit.

[Fly Boomer]

11 minutes ago, Shadrach said:

There are a few folks here that have coaxed genuinely impressive speed gains out of already above average flying airframes but it takes time and attention. A task I might be up for.

Sorry.  I wasn't really paying attention to who (whom?) I was responding.  Point well taken.  I'm always torn between trying to make things better (or at least inspecting) on one hand, and the Mike Busch philosophy of not messing with things that are working on the other hand.

[A64Pilot]

 I can’t imagine Mooney didn’t get the rigging correct, last thing in the manufacturing process an aircraft is inspected by a DMIR (Designated Manufacturers Inspection Representative) for conformity. My DMIR refused to do the inspection until after the test flight, which irritated me, but his concern was that I could do something to make the aircraft no longer conforming. 

Then of course the Test Pilot inspected it prior to flight and flight controls get special interest.

I’d be very surprised if it left that way.

Of course record any adjustment if in the really unusual case it slows down, you can always put it right back.

My bet is that it won’t make any measurable difference, but by putting it to spec you will be correcting a discrepancy. But who knows you may pick up a kt or two. I think you will, but a kt or two is tough to validate.

[EricJ]

10 minutes ago, Shadrach said:

I don’t think any of the rod ends can be turned unless disconnected. I was assuming the “B” nuts for each rod end could be loosened and the tube turned to adjust length. Is this not the case?

Surprisingly there is almost no play from one side to the other. Someone with no knowledge of geometry might think they were a single unit.

The rod ends would have to be threaded opposite directions in order to allow adjustment by turning the rod like a turnbuckle, and I doubt that's the case.   There are a few different kinds of rod ends used, but usually the difference is whether they're threaded in the rod or held in with roll pins, pressed, welded, etc.    I don't know of any left-hand threaded rod ends being used, but who knows.

[Shadrach]

10 minutes ago, Fly Boomer said:

Sorry.  I wasn't really paying attention to who (whom?) I was responding.  Point well taken.  I'm always torn between trying to make things better (or at least inspecting) on one hand, and the Mike Busch philosophy of not messing with things that are working on the other hand.

For complex machinery like engines, etc…I am totally against fishing expeditions. Turning a rod into a few times to match up my elevators should easily be undone…famous last words.

[Shadrach]

24 minutes ago, EricJ said:

The rod ends would have to be threaded opposite directions in order to allow adjustment by turning the rod like a turnbuckle, and I doubt that's the case.   There are a few different kinds of rod ends used, but usually the difference is whether they're threaded in the rod or held in with roll pins, pressed, welded, etc.    I don't know of any left-hand threaded rod ends being used, but who knows.

I thought the nose gear linkages had reverse threads on one end to facilitate preload adjustments, but I could be misremembering.

[A64Pilot]

Left hand thread rod ends aren’t uncommon, we used them on our aileron servo tabs, for the express purpose of breaking the jam nut loos and adjusting like a turnbuckle.

I wouldn’t expect one to be here though as I wouldn’t expect once assembled that any adjustment would be required.

If the airplane hadn’t been in the family, I’d bet the elevator had been replaced. Being where they are, they are often damaged

[gmonnig]

21 hours ago, Shadrach said:

So the question is could I gain a knot or two with careful rigging? My bird is upper end of speed for an M20F (150+KTAS) but one of the aileron horns protrudes ever so slightly above the wing tip in level flight and the elevators are not precisely matched.

 

I'll let you know what I find out. I feel like I have a fast-ish E model. I was doing 145-147kts TAS with the step not retracted. The step is safetied up now (plane is in the shop for new windshield and electric step conversion) and I'm doing 148-150kts now. My ailerons are slightly off in cruise too. I think a rigging will make her even faster! There is a Mooney Service Center at my home drome, so I'll call them tomorrow.

[Guest]

No left hand threaded rod ends in a Mooney that I’ve ever seen, that’s a Piper Cherokee flap thing.  Item 49 is the elevator aft pushrod.  The forward bearing is a special rod end which is drilled and pinned to the tube, the aft end has a sleeve which is also pinned to the tube, the threaded aft rod end is screwed into this sleeve and secured with a jam nut.

 Clarence 

[Shadrach]

1 hour ago, gmonnig said:

I'll let you know what I find out. I feel like I have a fast-ish E model. I was doing 145-147kts TAS with the step not retracted. The step is safetied up now (plane is in the shop for new windshield and electric step conversion) and I'm doing 148-150kts now. My ailerons are slightly off in cruise too. I think a rigging will make her even faster! There is a Mooney Service Center at my home drome, so I'll call them tomorrow.

From what I’ve read a well rigged E is good for 155kts+ with the balls to the wall. Good luck! 

[gmonnig]

1 hour ago, Shadrach said:

From what I’ve read a well rigged E is good for 155kts+ with the balls to the wall. Good luck! 

That would be nice. All the POH numbers numbers suggest that this plane should be damn near as fast as my Comanche 250. Nope, I’m at least 10-15kts slower. I think Mooney was optimistic on some of their numbers. The goal is to get to 155 on 10gph, (my 250 was a 161ktas at 13-14gph). Even with the crap 100LL prices, I haven’t felt the squeeze because of fuel burn difference. 

[Shadrach]

9 hours ago, gmonnig said:

That would be nice. All the POH numbers numbers suggest that this plane should be damn near as fast as my Comanche 250. Nope, I’m at least 10-15kts slower. I think Mooney was optimistic on some of their numbers. The goal is to get to 155 on 10gph, (my 250 was a 161ktas at 13-14gph). Even with the crap 100LL prices, I haven’t felt the squeeze because of fuel burn difference. 

My F runs very close to my buddy’s old Comanche 250. So close as to make almost no difference in block speed. You should  see 150kts without much trouble. 

[Guest]

18 hours ago, gmonnig said:

That would be nice. All the POH numbers numbers suggest that this plane should be damn near as fast as my Comanche 250. Nope, I’m at least 10-15kts slower. I think Mooney was optimistic on some of their numbers. The goal is to get to 155 on 10gph, (my 250 was a 161ktas at 13-14gph). Even with the crap 100LL prices, I haven’t felt the squeeze because of fuel burn difference. 

In my experience a clean 250 should out run an E model, unless the E model is highly modified, in which case it should be a match.

Clarence

[Shadrach]

18 hours ago, gmonnig said:

That would be nice. All the POH numbers numbers suggest that this plane should be damn near as fast as my Comanche 250. Nope, I’m at least 10-15kts slower. I think Mooney was optimistic on some of their numbers. The goal is to get to 155 on 10gph, (my 250 was a 161ktas at 13-14gph). Even with the crap 100LL prices, I haven’t felt the squeeze because of fuel burn difference. 

https://web.archive.org/web/20160218210613/https://www.mooneypilots.com/mapalog/m20e.html

[cliffy]

With your elevators at different angles static and neautral as shown they were disconnected at one time and reconnected incorrectly. 

They DID NOT  leave the factory this way!!!  Every airplane has undocumented maintenance in its history, every one, period. 

They should be even in deflection at ZERO stabilizer (thrust line) and faired evenly. Airplane needs to be level 4 ways- this means jacks underneath. 

Yours are not. 

As with many items Mooney there is no "quick fix" to do it right.

You need to start from ground zero and do a complete rigging according to the maintenance manual. You won't find any short cuts that work. Too many 

places to check for proper rigging to drop in the middle some where.  Sorry to be the bearer of bad news. 

Its no different than a landing gear rig. You gotta start from the beginning. 

Once the elevators are square with each other (from the begining) then you get to set the bungee deflections FOLLOW THE MANUAL AND TCDS LIMITS FOR YOUR AIRPLANE (they are different for different models of Mooneys- INCLUDING down to serial numbers in some cases). 

Once that is done then you get to reset the trim indicator (IIRC 2 degrees LE down stabilizer is the middle of the TO trim  but check it out) 

With all the anomolies you talk about on your trimming you have but one choice but to start from ground zero on all 3 axis and rerig per the manual

I know of no added bendable trim tabs on Mooneys.  The balancing of each control surface can/will be upset by adding extra unauthorized trim tabs. 

I find it interesting that after so many years on this forum we always seem to come around the same corner and retell the same issues 

Maybe, hopefully, this can help some newer Mooney owners apprciate the unique nature of the airplane we fly. 

 

[Yetti]

I would run the trim up and down and make various measurements along the way of both sides.    In level flight that is not how the elevator sits depending on loading.   You will find that mostly the anitiflutter weight is about up 3/4 of an inch from level.   So I would put the trim there and see how they look.