Replacing M20B rudder bellcrank?

[lifftchi]

Hi everyone,

So I've been finding that, even in pretty light crosswinds (maybe 5kts xwind component), the M20B rudder authority isn't that great.  I know that there's been some discussion on this in the past, with advice to replace the rudder bellcrank with the M20C version.  (http://mooneyspace.com/topic/8340-crosswind/?do=findComment&comment=88938 , and http://www.mooneyevents.com/cmodel.htm .)

I'd like to have this done, but the description seems a little terse.  Is there anything more involved?  I can buy the part and give it to my mechanic, but it's not clear to me how the stops should be adjusted.  I also don't know what needs to be done from a regulatory standpoint.  Any advice?

[carusoam]

How familiar with Mooneys is your mechanic?

The longer rudder and longer rudder throw are both greatly appreciated.

Essentialy you are converting a B tail to a C tail.  All of the C tail procedures including settings will be followed.

Documentation of the time being 'terse' is a complement. 

I would prefer to have somebody that works on the control surfaces of my plane be one that has done it before.  Not reading the manuals for the first time.  Too critical, too easy to mis-install hardware and too tersely documented...

This topic has come up before.  With some search effort, it may still be available...

I found some old memories while searching here...

http://mooneyspace.com/topic/1888-wind-how-much-wind-is-too-much/#comment-20494

I am only a PP, not a mechanic.

Best regards,

-a-

[mike20papa]

Just where is this bellcrank? I don't think the rudder replacement is practical as it would require basically changing out the empenage.  I know the lack of right rudder thing as I fly an A model.  Take off is always right foot hard to the floor..if you dare let up even just a little, there is not enough right rudder to bring it back.  You can be looking at the left side of the runway at lift off.  On xwind landings, I find the rudder/aileron balance adequate.  In other words, if I'm in a strong enough x wind I can't track the runway on final with bank (aileron) yaw (rudder) is not my concern.

Probably a phone call to the guys at LASAR is the best bet to find out what's involved.

[lifftchi]

 

5 hours ago, mike20papa said:

Just where is this bellcrank? I don't think the rudder replacement is practical as it would require basically changing out the empenage.  I know the lack of right rudder thing as I fly an A model.  Take off is always right foot hard to the floor..if you dare let up even just a little, there is not enough right rudder to bring it back.  You can be looking at the left side of the runway at lift off.  On xwind landings, I find the rudder/aileron balance adequate.  In other words, if I'm in a strong enough x wind I can't track the runway on final with bank (aileron) yaw (rudder) is not my concern.

Probably a phone call to the guys at LASAR is the best bet to find out what's involved.

Yeah, I definitely hold the right pedal down on takeoff.  It's especially bad when I let go while trying to pull up the gear.  The plane goes sideways pretty fast.

The bellcrank is a pretty small part in the tail section (I think). It's part of the control linkages, not the rudder itself.  That would be a big job!

That's a good point about landings.  I haven't had crosswinds strong enough to not be able to track the runway -- it's gotten to the point where I was using most of the available rudder, and my perception was that I still had some bank to work with.  Could be wrong there.

[lifftchi]

5 hours ago, carusoam said:

How familiar with Mooneys is your mechanic?

The longer rudder and longer rudder throw are both greatly appreciated.

Essentialy you are converting a B tail to a C tail.  All of the C tail procedures including settings will be followed.

Documentation of the time being 'terse' is a complement. 

I would prefer to have somebody that works on the control surfaces of my plane be one that has done it before.  Not reading the manuals for the first time.  Too critical, too easy to mis-install hardware and too tersely documented...

This topic has come up before.  With some search effort, it may still be available...

I found some old memories while searching here...

http://mooneyspace.com/topic/1888-wind-how-much-wind-is-too-much/#comment-20494

I am only a PP, not a mechanic.

Best regards,

-a-

Thanks for the link!  Good point about the mechanic.  Mine has a fair amount of experience, including pretty complete rebuilds on various aircraft types, but I'm not sure that he's actually got relevant experience for this project.  I'll have to think about it some more.

[lifftchi]

1 hour ago, pmccand said:

I have an M20B and feel your pain.  I have also tried to change the bellcrank using a "C" model bellcrank part.  Now having said this, you need to realize that you can't legally change the bellcrank to another part number as it is a modification which would alter the flight characteristics of your aircraft and deviate from your TCDS (yes rudder travel is specified in the TCDS).  The most common way to deviate from this would be the obvious 337 or STC.

HOWEVER, there is a little-known workaround this from the Fred Flinstone days in the form of a letter from the manufacturer stating that the part is acceptable to use in the "B" as as it shows no significant design changes from the "B" to the "C" model...

I have such a letter from Mooney.  I got mine through Paul at LASAR.

Now here's the bummer...  I installed the "C" model bellcrank in my "B", but I have a bulkhead in the tail section of the fuselage that the bellcrank banged into in one direction of the rudder motion..  It would allow the full "C" model deflection in one direction, but not the other.  I could not find an acceptable resolution to this, so I removed the "C" bellcrank and tossed it into my spare parts bin and steamed off.  I guess I will just learn to live with the limits of the +/-18 degree rudder...  (Pfffft!)

 

Thanks, this is great info.  I hadn't known about that workaround.  I had guessed that a 337 would be necessary.

Also interesting to hear that it didn't work -- that's a tidbit that I hadn't turned up in my searching.  I'll have to look at the bulkheads and such.  It also looks like I'll be calling LASAR at some point soon.