travel boards in Europe / how to check rigging with a protractor

[tmo]

I am looking to borrow a EU based set of travel boards that would work for a 1980 M20K, to buy a set (location not critical), or a drawing / CAD file to have them fabricated locally.

Absent that option, can someone please describe the process using a protractor? I have not been able to find a description on how to do it without the boards. The Service and Maintenance Manual I have tells me to use the travel boards (27-30-00). I am looking at the elevator, since it seems the easiest, but would want to do all of them eventually. I've seen a few people mention it is doable but tedious, so I want to give it a shot. I don't think I have a need to adjust anything, just want to go through the motions as a learning exercise. I know the angles are in the TCDS, but am not sure how to apply those values / what to measure them against.

Many thanks in advance!

Edited August 2, 2020 by tmo

[EricJ]

28 minutes ago, tmo said:

I am looking to borrow a EU based set of travel boards that would work for a 1980 M20K, to buy a set (location not critical), or a drawing / CAD file to have them fabricated locally.

Absent that option, can someone please describe the process using a protractor? I have not been able to find a description on how to do it without the boards. The Service and Maintenance Manual I have tells me to use the travel boards (27-30-00). I am looking at the elevator, since it seems the easiest, but would want to do all of them eventually. I've seen a few people mention it is doable but tedious, so I want to give it a shot. I don't think I have a need to adjust anything, just want to go through the motions as a learning exercise. I know the angles are in the TCDS, but am not sure how to apply those values / what to measure them against.

Many thanks in advance!

The Maintenance Manual is available free online if you don't have one, and in the SMM for the J (which I think is the same as the K in this case) elevator rigging is in section 27-30.  Basically, level the airplane, align the stabilizer (via trim) and elevator with the level screws or the sheet metal seam along the avionics hatch/empennage (Fig 27-3A), and adjust travel between the stops to +/- 22 degrees with +/- 2 degrees tolerance at each end.   There is guidance in the manual regarding about where the various adjustments should be at that point, but the main thing is that it hits the stops with those deflections from neutral.    So a digital level/protractor can be used easily to do this, especially since the travel boards are pretty rare, even in the states.   The "station" mentioned for the travel board is the location on the elevator where the measurement should be made, and Fig 27-3A shows this as well.

Edited August 2, 2020 by EricJ

[Hank]

1 hour ago, EricJ said:

The Maintenance Manual is available free online if you don't have one, and in the SMM for the J (which I think is the same as the K in this case) elevator rigging is in section 27-30.  Basically, level the airplane, align the stabilizer (via trim) and elevator with the level screws or the sheet metal seam along the avionics hatch/empennage (Fig 27-3A), and adjust travel between the stops to +/- 22 degrees with +/- 2 degrees tolerance at each end.   There is guidance in the manual regarding about where the various adjustments should be at that point, but the main thing is that it hits the stops with those deflections from neutral.    So a digital level/protractor can be used easily to do this, especially since the travel boards are pretty rare, even in the states.   The "station" mentioned for the travel board is the location on the elevator where the measurement should be made, and Fig 27-3A shows this as well.

The problem with this is that the wing and tail surfaces are not flat, they are sloped top and bottom at dissimilar angles. Travel boards take these angles into account, and follow a third taper angle to the Zero point. 

You may come close by aligning the upper and lower control surfaces with the airfoil, and measure the deflection angle from the hinge point.

Not an A&P, but I've seen a set of travel boards used on my plane . . . .

[EricJ]

3 hours ago, Hank said:

The problem with this is that the wing and tail surfaces are not flat, they are sloped top and bottom at dissimilar angles. Travel boards take these angles into account, and follow a third taper angle to the Zero point. 

You may come close by aligning the upper and lower control surfaces with the airfoil, and measure the deflection angle from the hinge point.

Not an A&P, but I've seen a set of travel boards used on my plane . . . .

With the elevator "flat" as per the SMM, which can be aligned using the balance weights as reference once the trim is flat wrt the empennage seam, a digital level/protractor can be set to zero while on the elevator.   It will then indicate when the elevator has deflected up or down 22 degrees, as indicated in the SMM.

Did it both ways in A&P school.   I found the digital level to be easier and faster and more repeatable, but that's just me.   Travel boards can be kind of a pain and are still subject to significant errors.  

[tmo]

Thanks, guys. This is great.

I did look, many times, over SMM 27-10-00 but when looking at the description under Fig. 27-8 (.. with travel board ..) I assumed the process there requires them. Thank you for explaining how my understanding was wrong. Reads like I'll be able to tackle the challenge.

Now, to properly level the plane, I need the "jack points" instead of the tie-down rings I currently have. Are they really just a screw with a washer shaped like the Apollo command module so it sits well in the jacks? Asking, because waiting for a set from LASAR (or Dan, if he hasn't sold his yet) will take many weeks, and it looks like something I could have made locally within the hour, based on the tie-down rings currently installed.

EDIT: I now see I should be able to do the elevator by letting air out of the front wheel. Even better. But I'd still want to make, or buy, a set of jack points, so the above question stands. Might do a W&B while we're having fun, why not.

Are other control surfaces much harder to verify rigging on? If there are any tricks to doing them well, I'd love to learn them before we move forward.

I'm trying to learn my plane while bribing a couple of the local EASA certified mechanics to take an interest in it, so I have a local resource when a need comes. So far it's been working, and dare I say, it's been a learning experience, both for me, of course, but also for them. We got some of the inspection panels off, they got to complain how non-Cessna all the solutions were, but after one of them commented that it is like some of the gliders they maintain, things got interesting.

As a bonus, I'll get to play with the emergency gear extension mechanism, yay!

At a risk of sounding like a broken record - thanks, guys, this is great!

Edited August 3, 2020 by tmo
added bit about air in front wheel (proving I can read and understand, if I try real hard)

[Guest]

11 hours ago, EricJ said:

The Maintenance Manual is available free online if you don't have one, and in the SMM for the J (which I think is the same as the K in this case) elevator rigging is in section 27-30.  Basically, level the airplane, align the stabilizer (via trim) and elevator with the level screws or the sheet metal seam along the avionics hatch/empennage (Fig 27-3A), and adjust travel between the stops to +/- 22 degrees with +/- 2 degrees tolerance at each end.   There is guidance in the manual regarding about where the various adjustments should be at that point, but the main thing is that it hits the stops with those deflections from neutral.    So a digital level/protractor can be used easily to do this, especially since the travel boards are pretty rare, even in the states.   The "station" mentioned for the travel board is the location on the elevator where the measurement should be made, and Fig 27-3A shows this as well.

How do you set the stabilizer in the correct neutral position without the travel board?  The stabilizer/elevator board has 2 parts, the first is a platform which you set your level on, this allows you to set the stabilizer at the correct incidence angle relative to the fuselage levelling points.  Without this tool you have no idea where to place your level and what angle it’s set to.

The second part is a curved scale to measure and adjust the elevator travel.  I’ve never compared this scale to a digital inclinometer but will do it soon.

Clarence

[tmo]

I understand this process is to align the chord line of the stabilizer + elevator at 0 degrees (neutral) with the level line defined by the leveling reference screws above the large inspection panel, where the battery and avionics live. This is done using trim. While they will not be the same line, they will be parallel to each other. Measuring the 20 degrees deflection then uses that chord line as a reference.

I'll attempt to take pictures when we do our measurements, so if I'm doing it wrong, you can point out where the error is.

[skykrawler]

I found that jacking the airplane to get it level required a raising the airplane substantially more than required to swing the gear.   This results in climbing in and out of the airplane to set the stab when high on jacks.   Using a digital level or iPhone app the angle of leveling points on the access panel can be obtained for reference and subtracted from the value obtained for the stabilizer.  The stab can then be set neutral without leveling the airplane. 

 

[EricJ]

2 hours ago, M20Doc said:

How do you set the stabilizer in the correct neutral position without the travel board?  The stabilizer/elevator board has 2 parts, the first is a platform which you set your level on, this allows you to set the stabilizer at the correct incidence angle relative to the fuselage levelling points.  Without this tool you have no idea where to place your level and what angle it’s set to.

The second part is a curved scale to measure and adjust the elevator travel.  I’ve never compared this scale to a digital inclinometer but will do it soon.

Clarence

One way is to pick a spot on the stabilizer and measure the angle from horizontal on both the top and bottom surface.   If the surfaces aren't parallel you can subtract half the difference to get the angle from level.

Another way (I use sometimes to level scales to weigh race cars) is to put a water level (clear tube with water in it) with ends on the leading and trailing edge.  When the ends match the water levels, it's level.   This requires that the airplane be level, though, and the other way you can work from whatever angle the airplane is measured at.

There are probably more ways to do it. 

[RLCarter]

2 hours ago, skykrawler said:

I found that jacking the airplane to get it level required a raising the airplane substantially more than required to swing the gear.   This results in climbing in and out of the airplane to set the stab when high on jacks

I’m still not a fan of having my plane on jacks, I have leveled mine several times for various reasons. I have (2) 2x12’s cut to 14” which are placed on 14x14x3/4” plywood, then lower the nose air pressure to level it out. My hangar floor is pretty level so left to right has never been an issue but if it had needed it I would have adjusted the tire pressure on the mains

[Guest]

4 hours ago, EricJ said:

One way is to pick a spot on the stabilizer and measure the angle from horizontal on both the top and bottom surface.   If the surfaces aren't parallel you can subtract half the difference to get the angle from level.

Another way (I use sometimes to level scales to weigh race cars) is to put a water level (clear tube with water in it) with ends on the leading and trailing edge.  When the ends match the water levels, it's level.   This requires that the airplane be level, though, and the other way you can work from whatever angle the airplane is measured at.

There are probably more ways to do it. 

All of that is fine but is not in the Maintenance Manual.  As we’re checking/adjusting flight control travels which are called out in the type certificate I’d prefer to use the Mooney tool and process.  As professional maintainers it’s what we’re supposed to do.

Clarence

[EricJ]

16 minutes ago, M20Doc said:

All of that is fine but is not in the Maintenance Manual.  As we’re checking/adjusting flight control travels which are called out in the type certificate I’d prefer to use the Mooney tool and process.  As professional maintainers it’s what we’re supposed to do.

Clarence

Which is awesome when travel boards are available.   Nearly always these days they're not.

 

[carusoam]

TMO,

If the Jack point question didn’t get answered....

They are machined inverted Christmas tree looking devices.... the tree trunk is small enough in diameter to fit in the threaded hole, but not threaded in place....  The point fits into the cavity of the jack...

So it is aptly named the jack point...

Lasar sells some fancy device that is both a jack point and a tie down ring at the same time.... nicely machined, bolt, and heavy gauge sheet metal....

Best regards,

 -a-

[tmo]

Thanks A; I actually found this thread on jack points and have already found possible solutions in my box of mixed screws; will remove the tie-down rings and make sure the metric thread matches, if it does not, I'll make a set on a lathe or have one CNCed for me. I have to make sure the jacks we have at the club will fit under the Mooney.

[tmo]

15 hours ago, M20Doc said:

All of that is fine but is not in the Maintenance Manual.  As we’re checking/adjusting flight control travels which are called out in the type certificate I’d prefer to use the Mooney tool and process.  As professional maintainers it’s what we’re supposed to do.

Clarence, I fully agree with you, and I hope to eventually pick up a set of travel boards, or, preferably, plans to make them, but for the time being I just want to see where I can get without them. We will not be making any adjustments, just checking it all out. If our checks indicate that something is amis (which I don't expect to happen, the plane flies well), I'll either check in with the German MSCs, or up my search for the boards.

But for what I want to attempt, the solutions proposed by Eric sound workable.

Wouldn't it be grand if Mooney updated the procedures to take advantage of modern tools?

[Hank]

1 hour ago, tmo said:

Thanks A; I actually found this thread on jack points and have already found possible solutions in my box of mixed screws; will remove the tie-down rings and make sure the metric thread matches, if it does not, I'll make a set on a lathe or have one CNCed for me. I have to make sure the jacks we have at the club will fit under the Mooney.

Your threads are likely not metric, unless someone before you has modified them. Mine are 5/16", I think; standard pitch, not fine, I just don't remember. I keep a pair of socket head cap screws on my hatrack to use in a pinch, the jack point fits nicely in the spot made for the allen wrench.

[M20F-1968]

I have made travel boards for myself and have the necessary templates to do it again.  The problem comes is that making them by hand is an arduous process.  

If there are enough people interested I may be convinced to make them again. 

John Breda 

[EricJ]

2 hours ago, M20F-1968 said:

I have made travel boards for myself and have the necessary templates to do it again.  The problem comes is that making them by hand is an arduous process.  

If there are enough people interested I may be convinced to make them again. 

John Breda 

Somebody needs to put it in a cad file so that they can be laser cut and etched cheaply.

[M20F-1968]

17 hours ago, EricJ said:

Somebody needs to put it in a cad file so that they can be laser cut and etched cheaply.

My mechanic tried that route and the scale was cut into the travel board itself (Aluminum).  The geometry was not accurate.  One could cut the travel board outline byt laser or other similar device, but the scale should be hand fitted and calibrated.  I think it would be unlikely that the CAD file can be programmed so that the scale is appropriately and accurately aligned and cut out into the body the the Travel Board the first time.  it would likely be a more involved trial and error process.  An accurate protractor scale, hand fitted and calibrated to the rest of the Travel Board, and attached so it would not move, is likely an option.  Then there is the question of how to make the scale.  They have been made by graphics arts (sign shops) as a full scale copy, but these would be acrylic mounted on a har surface.  Silkscreened is not work.

John Breda