Hanging Wheel

[Tony__L]

Hi All,

 

I have a problem, I think, with my right wheel/gear hanging down a bit while in flight.  Now, I have shown this to my maintenance organisation who said that this is normal and that it doesn't look nearly as bad from the front (see Before picture, without snow).  The plane was in for some maintenance shortly after this picture was taken and they worked on the rigging and said that nothing more can be done (see After picture, with snow)!  Unfortunately I could not see what it was like when it was on the ground and on the stand to see what it looked like from the front.

 

Surely though this is not as good as it gets?  What effect if any will this have on performance?

 

Any advice on how to get this sorted out, bearing in mind that I am in South Africa.

 

Thanks

 

Tony

[Marauder]

The gear should not hang down like this. I had a gear hanging lower than the other and the owner's mechanic before me thought it was fine to "trim" out the drag by playing with the flight surfaces.

It caused drag and slowed my plane by several knots. Your pictures should be enough to convince him this is a problem.

[Bob - S50]

Take it to a Mooney Service Center.  See what they say.

[Tony__L]

The gear should not hang down like this. I had a gear hanging lower than the other and the owner's mechanic before me thought it was fine to "trim" out the drag by playing with the flight surfaces.

It caused drag and slowed my plane by several knots. Your pictures should be enough to convince him this is a problem.

 

I showed them the picture and they said it was not unusual.  I don't think this is correct!  

[Tony__L]

Take it to a Mooney Service Center.  See what they say.

 

I have!  I have taken it to the Mooney agents, both sales and service, for Africa. 

[Tony__L]

Put the plane up on jacks and take a look.  My manually-operated M20B has the exact same thing happening on the left wheel, and I have scheduled a repair to the short 5" over center linkage member associated with the landing gear.  This will require the complete removal of the landing gear, as the bolts are forward-mounted and cannot be removed without dropping the gear.  This worn part does not affect the lock-down overcenter gear-down lock linkage, and it doesn't immediately affect safety (at least on my bird), but it does need to be repaired.

 

Phil Mc

 

Thanks, I will ask them about the 5" linkage and see what they say.

[N201MKTurbo]

To get this right will take a bit of work. First off what kind of plane is it?  Does it have manual or electric gear?

 

It only gets this way if someone  has done major repairs to the gear system and not rigged it correctly.

 

Start by removing the links from the main gear doors so the doors hang freely.

 

You will be adjusting the long rods with the springs in them on each leg.

 

Shorten the rod on low hanging leg by 1/2 turn, lengthen the rod on the other leg by the same amount. Do this until the two legs hang even.

 

 It is easy to adjust these rods when the gear is in the 1/2 retracted position.

 

Next you want to adjust  the length of the rods so the springs are 1/2 compressed with the gear down and locked. If they are not compressed at all your preloads will be too light if they are completely compressed you risk damaging the system. You can tell that they are completely compressed because all the coils will be touching each other.

 

If one is too lightly compressed lengthen both rods the same amount until both springs are compressed and not over compressed. Check your preloads they should be correct. if not adjust both rods the same amount until they are in range. If they won't get high enough without fully compressing one of the springs consider replacing the springs.

 

Put the gear up and re-attach the gear doors and re-rig the links so they close completely.

[Tony__L]

To get this right will take a bit of work. First off what kind of plane is it?  Does it have manual or electric gear?

 

It only gets this way if someone  has done major repairs to the gear system and not rigged it correctly.

 

Start by removing the links from the main gear doors so the doors hang freely.

 

You will be adjusting the long rods with the springs in them on each leg.

 

Shorten the rod on low hanging leg by 1/2 turn, lengthen the rod on the other leg by the same amount. Do this until the two legs hang even.

 

 It is easy to adjust these rods when the gear is in the 1/2 retracted position.

 

Next you want to adjust  the length of the rods so the springs are 1/2 compressed with the gear down and locked. If they are not compressed at all your preloads will be too light if they are completely compressed you risk damaging the system. You can tell that they are completely compressed because all the coils will be touching each other.

 

If one is too lightly compressed lengthen both rods the same amount until both springs are compressed and not over compressed. Check your preloads they should be correct. if not adjust both rods the same amount until they are in range. If they won't get high enough without fully compressing one of the springs consider replacing the springs.

 

Put the gear up and re-attach the gear doors and re-rig the links so they close completely.

 

Hi Turbo

 

Sorry, I should have added some specifics in my original post.  Plane is 1967 M20F Executive.  Gear is manually operated.

 

Thanks for your advice and will run it by my AMO to see what he says!

 

Tony

[Hank]

My plane began not fully retracting one wheel during cold weather. Sometimes I could lower and raise it again and it would go up; sometimes it would go up by itself after 10, 20 or 30 minutes and the plane would accelerate almost 10 MPH. Your post surprised me because old pucks show up like this in winter, and right now temperatures are in the mid-30C range; then you mentioned S. Africa, and it's winter there.

Replacing the pucks cured this immediately, made for smoother taxiing and softer landings.

Bad news: 11 pucks at $105 each, and expect 4-6 hours labor if they know what they're doing, more if they don't. A special tool is required to compress the new pucks at install; several people can sit on the wing to compress the main gear pucks, but that won't work for the nose gear. Someone here has made the tool and may share the plans with you.

Your gear should retract fully on both sides, hanging down is NOT normal.

Check your pucks, they have the manufacturing date molded into the edge. If they are more than 10 years old, they are most likely the culprit. Good luck, and fly safe.

[N201MKTurbo]

As far as the over center links are concerned, the aluminum link can get worn where it pushes against the steel link. It can take more extension of the retraction rod to get the preloads correct with worn links.

 

If you remove the retraction rods so you can swing the gear by hand, you can remove the over center assemble without removing the gear leg.

[Tony__L]

Thanks for all the advice and tips! Keep them coming :-)

[cliffy]

You should have a small rubber pad in the top of your wheel well The gear should just touch this pad when retracted. Put the bird on jacks, raise the gear and then go push up on the wheel to see how much "play" you have between hanging and up against the pad. With the gear partly retracted disconnect the two retract rods for the main gear at the johnson bar (retract handle) and then push the gear down and locked. Check for wear in the down lock links by trying to move the wheel toward and away from the wing tip. If you have play find the offending bolts, bushings or rod ends.

One last item. Has the plane ever been landed gear up or collapsed? If it has and the link rods from the johnson bar to the bellcrank may have been changed and the wrong ones installed. I ran into this on a shop bird not too long ago. 

BTW, I have friends up near Warmbath SA.Limpopo area. 

[Tony__L]

You should have a small rubber pad in the top of your wheel well The gear should just touch this pad when retracted. Put the bird on jacks, raise the gear and then go push up on the wheel to see how much "play" you have between hanging and up against the pad. With the gear partly retracted disconnect the two retract rods for the main gear at the johnson bar (retract handle) and then push the gear down and locked. Check for wear in the down lock links by trying to move the wheel toward and away from the wing tip. If you have play find the offending bolts, bushings or rod ends.

One last item. Has the plane ever been landed gear up or collapsed? If it has and the link rods from the johnson bar to the bellcrank may have been changed and the wrong ones installed. I ran into this on a shop bird not too long ago. 

BTW, I have friends up near Warmbath SA.Limpopo area.

Another good tip, thanks :-)

[N201MKTurbo]

You must be talking about the bolt that attaches the over center link to the gear leg. If I recall the last time I did it there was a cut out in the sheet metal that allowed the bolt to slide out. I will be out at the hanger tomorrow, I'll take another look at it.

The only thing hard about removing the gear leg is that damn garage door spring. I have the special tool for it. It helps a little...

[N201MKTurbo]

Yes, now that you mention it someone on here did recommend it. Give us a pilot report on how it works.

[carusoam]

Believe it or not...

Put quarters and spring in the search area, and you get a list of things...

http://mooneyspace.com/topic/5604-gear-rigging-tools/?hl=%2Bspring+%2Bquarters#entry91000

Remember to search the forums or you will get this thread.

Best regards,

-a-