Another rigging question ...

[170driver]

Hello All,

 

During annual in July of last year the flaps on my '68 C were adjusted. They hadn't been extending as far as the should, and when retracted they were a bit "high" so that on the starboard side the corner of the inboard trailing edge contacted the fairing and rubbed a small hole in it.

Now, with the yoke centred the trailing edges of the flaps and ailerons are perfectly in line, but the aileron counterweights are sitting about 1/2" high of the wing surface on each side.

It seems to me that I must be losing some cruise speed, both from the drag of the counterweights sticking up in the wind and from the bit of extra camber in the wing. The plane flights pretty straight - verrrry slow left turn when trimmed in cruise with PC disconnected. I know tinkering with rigging can open a can of worms, so I'd like to ask the Mooney spacers who have faced this situation - is it worth adjusting all the trailing edges up so the counterweights lie flush? Might have to bend the flap to fuselage fairing up a tiny bit - otherwise the same number of turns would be required on each side to make the adjustment.

 

Dave

1968 M20C

C-GAVX

 

 

Sent from my iPhone using Tapatalk

[RLCarter]

Your going to need the "Travel Boards" to rig correctly

[Guest]

  On 2/11/2018 at 5:05 AM, 170driver said:

 

Hello All,

 

During annual in July of last year the flaps on my '68 C were adjusted. They hadn't been extending as far as the should, and when retracted they were a bit "high" so that on the starboard side the corner of the inboard trailing edge contacted the fairing and rubbed a small hole in it.

Now, with the yoke centred the trailing edges of the flaps and ailerons are perfectly in line, but the aileron counterweights are sitting about 1/2" high of the wing surface on each side.

It seems to me that I must be losing some cruise speed, both from the drag of the counterweights sticking up in the wind and from the bit of extra camber in the wing. The plane flights pretty straight - verrrry slow left turn when trimmed in cruise with PC disconnected. I know tinkering with rigging can open a can of worms, so I'd like to ask the Mooney spacers who have faced this situation - is it worth adjusting all the trailing edges up so the counterweights lie flush? Might have to bend the flap to fuselage fairing up a tiny bit - otherwise the same number of turns would be required on each side to make the adjustment.

 

Dave

1968 M20C

C-GAVX

 

 

Sent from my iPhone using Tapatalk

 

Expand  

The aileron mass balance should be flush with the notch in the wing tip in cruise flight, the flaps should be even with them as well.

The manual allows for drooping both down maximum of 2 degrees. The amount depends on how much free play there is in the control system.

Clarence

[cliffy]

You need to pull both ailerons up at the same time to remove any slack in the system to see where they sit when "loaded" in flight. Static sitting they will always droop a little.  To rig then you need to start at Point 0 in the MM and work your way out to the wing tips. 

[N201MKTurbo]

The easiest way to adjust the aileron position is to loosen the jamb nut on the outboard rod end of the long tube that runs from the center link to the bell crank in the wings. Then remove the bolt between the tube and center link. 

Now you can easily rotate the whole tube 1/2 turn at a time. Much easier than trying to adjust anything at the bell crank.

As Cliffy says you need to adjust both the same. If you don't you won't end up with asymmetrical ailerons, you will end up with a tilted yoke.

my experience is the higher you rig the flaps and ailerons the faster your plane will go. Any amount of droop is like putting your flaps down.

Edited February 11, 2018 by N201MKTurbo

[170driver]

Okay, now the follow-on question that has been asked more than once ... where to get a set of travel boards? Hangar Toolbox seems to be defunct. I checked the zip file posted elsewhere on the forum and it contains a scan of the rudder travel board only. Does anyone have technical drawings of the wing boards for a C model, or is there another place to rent them from ?

[Guest]

  On 2/11/2018 at 5:31 PM, 170driver said:

Okay, now the follow-on question that has been asked more than once ... where to get a set of travel boards? Hangar Toolbox seems to be defunct. I checked the zip file posted elsewhere on the forum and it contains a scan of the rudder travel board only. Does anyone have technical drawings of the wing boards for a C model, or is there another place to rent them from ?

Expand  

There are only 2 MSC’s in Canada, one in Calgary, and mine in Ontario.  It’s not really a tool I’d ship across the country.  You may find an MSC south of the board who are closer and able to help you.

Do you have a maintenance manual for your plane?

Clarence

[170driver]

  On 2/11/2018 at 8:00 PM, M20Doc said:

There are only 2 MSC’s in Canada, one in Calgary, and mine in Ontario.  It’s not really a tool I’d ship across the country.  You may find an MSC south of the board who are closer and able to help you.
Do you have a maintenance manual for your plane?
Clarence

I have the maintenance and parts manuals for the plane. The shop that does the annuals is good about letting me do work under supervision. I haven't looked carefully at the manual yet, but it seems to me the rod ends at the flaps need to be lengthened an equal amount on each side to get the counterweights flush, and flap stops adjusted equally after that to get trailing edges aligned.

Dave


Sent from my iPhone using Tapatalk

[Guest]

  On 2/11/2018 at 9:28 PM, 170driver said:

I have the maintenance and parts manuals for the plane. The shop that does the annuals is good about letting me do work under supervision. I haven't looked carefully at the manual yet, but it seems to me the rod ends at the flaps need to be lengthened an equal amount on each side to get the counterweights flush, and flap stops adjusted equally after that to get trailing edges aligned.

Dave


Sent from my iPhone using Tapatalk

Expand  

The rod ends on the I/b ends of the flaps determine down travel, the stop bolts on the o/b end of the flaps controls up positioning.

Aileron rigging starts at the yokes, then the centre bellcrank positioning under the floor, then the aileron bellcrank positioning in the wings as measured from the spar face, then ultimately the aileron positioning based on a travel board.  However the mass balance should be centred in the wing tip notch in cruise flight and flaps should align with the ailerons.

Clarence

[170driver]

  On 2/11/2018 at 10:38 PM, M20Doc said:

The rod ends on the I/b ends of the flaps determine down travel, the stop bolts on the o/b end of the flaps controls up positioning.
Aileron rigging starts at the yokes, then the centre bellcrank positioning under the floor, then the aileron bellcrank positioning in the wings as measured from the spar face, then ultimately the aileron positioning based on a travel board.  However the mass balance should be centred in the wing tip notch in cruise flight and flaps should align with the ailerons.
Clarence

I meant to say rod ends at the ailerons, not the flaps. The yoke is properly centred in wings level cruise, and the plane flies more or less hands off with the PC disconnected, so wouldn't I just have to lengthen the rod end at each aileron by the same amount each side until the mass balances are centred? After that the flap stops would be adjusted "up" by the same amount on each side until trailing edges aligned with ailerons.

Dave


Sent from my iPhone using Tapatalk

[Guest]

  On 2/11/2018 at 10:48 PM, 170driver said:

I meant to say rod ends at the ailerons, not the flaps. The yoke is properly centred in wings level cruise, and the plane flies more or less hands off with the PC disconnected, so wouldn't I just have to lengthen the rod end at each aileron by the same amount each side until the mass balances are centred? After that the flap stops would be adjusted "up" by the same amount on each side until trailing edges aligned with ailerons.

Dave


Sent from my iPhone using Tapatalk

Expand  

From your description you have it correct.  I would also measure the positioning of the aileron bellcranks while you’re at it.

Clarence

[170driver]

  On 2/11/2018 at 11:20 PM, M20Doc said:

From your description you have it correct.  I would also measure the positioning of the aileron bellcranks while you’re at it.
Clarence

Thanks Clarence
Will probably be a couple of weeks before I get to this. I'll be sure to record before & after cruise speeds & post the numbers.


Sent from my iPhone using Tapatalk

[Sean S]

I am working on a 1976 M20F at the moment. Followed the rigging instructions in the manual and found a few rod ends that need adjustment. With the ailerons locked on neutral using a strait edge on the yoke they are properly faired a 0 to -2 degrees down. Once the straight edge is released they have a right wing down spring back. I must be missing something. Maybe @M20Doc or @Sabremech has some insight?

Video on you tube.

 

 

[N201MKTurbo]

  On 2/16/2018 at 3:39 PM, Bayern Speed said:

I am working on a 1976 M20F at the moment. Followed the rigging instructions in the manual and found a few rod ends that need adjustment. With the ailerons locked on neutral using a strait edge on the yoke they are properly faired a 0 to -2 degrees down. Once the straight edge is released they have a right wing down spring back. I must be missing something. Maybe @M20Doc or @Sabremech has some insight?

Video on you tube.

 

 

Expand  

To set the aileron positions properly you need to have someone on each aileron pushing up. that is what happens in flight. The spring back you are seeing is coming from the rudder aileron interconnect springs. Don't worry about it. You could remove the springs while you are rigging it if it makes things easier. 

[N201MKTurbo]

BTW, making everything look perfect is not what you are after, what you want is for your plane to fly straight and fast. The two will probably not happen at the same settings.

[Guest]

  On 2/16/2018 at 3:39 PM, Bayern Speed said:

I am working on a 1976 M20F at the moment. Followed the rigging instructions in the manual and found a few rod ends that need adjustment. With the ailerons locked on neutral using a strait edge on the yoke they are properly faired a 0 to -2 degrees down. Once the straight edge is released they have a right wing down spring back. I must be missing something. Maybe @M20Doc or @Sabremech has some insight?

Video on you tube.

 

 

Expand  

Is the nose wheel straight?  You’re getting some input from the aileron/rudder interconnecting springs under the pilot’s seat.

Clarence

Edited February 16, 2018 by M20Doc

[N201MKTurbo]

BTW you cannot get a Mooney to fly straight with travel boards. You can get it to a good starting place, but the final adjustments will need to be made with test flights.

[Sean S]

@M20Doc nose wheel is straight. Even jacked aircraft to get any possible unintended pressure from nose wheel out of the system. As far as I can tell it is the mixer springs. One appears visually to be tighter that the other. I guess we will go fly it and report back.

[Sean S]

  On 2/16/2018 at 4:00 PM, N201MKTurbo said:

To set the aileron positions properly you need to have someone on each aileron pushing up. that is what happens in flight. The spring back you are seeing is coming from the rudder aileron interconnect springs. Don't worry about it. You could remove the springs while you are rigging it if it makes things easier.

Expand  

I considered that! I think we will fly it and verify good or bad results.

[N201MKTurbo]

  On 2/16/2018 at 5:45 PM, Bayern Speed said:

I considered that! I think we will fly it and verify good or bad results.

Expand  

That is the best way. You will just have to look at them and say that it seems up about an 1/8" or so and then adjust them where you want them. Then repeat until you are tired of adjusting it.