New biscuits, very bouncy nose

[Bob_Belville]

3 minutes ago, Hyett6420 said:

Bob

mine got that pressure differential at the refit and olacarded as well. I'll take photos tomorrow for you. 

That's your J - 2900 gross?

[Lance Keve]

24 minutes ago, Bob_Belville said:

Lance, do you have documentation for that? My manual calls for 30 psi all around. '66E. (I can bounce pretty high with soft tires...)

 

3 minutes ago, Bob_Belville said:

Per the attached service manual (104 CDEF) the mains for C/D/E/F are all 6 ply and take 30 psi. The F only has a 6 ply nose wheel tire and takes 49 psi.

manual 104 CDEF tires page.pdf

Hi Bob - I'll have to do some digging.  As I recall, I'd seen it on MS from earlier discussions (few years back).  I checked with Air-Mods (MSC) and they said that was correct.  The reason I began thinking about it was my tires looked quite flat at 30.  Turned out they were 6-ply and required the newer, higher, psi pressure.  It doesn't bother me if it is a few lbs. less but down at 30 and they are really soft and noticeably don't roll as well.

[Lance Keve]

6 minutes ago, Lance Keve said:

 

Hi Bob - I'll have to do some digging.  As I recall, I'd seen it on MS from earlier discussions (few years back).  I checked with Air-Mods (MSC) and they said that was correct.  The reason I began thinking about it was my tires looked quite flat at 30.  Turned out they were 6-ply and required the newer, higher, psi pressure.  It doesn't bother me if it is a few lbs. less but down at 30 and they are really soft and noticeably don't roll as well.

Rang the MSC but A/P was offsite and in the middle of something.  Will check in with me tomorrow.  If I'm high on the mains, I'll concede.  Don't want any misleading info out there.  

[FoxMike]

Your mechanic may have put the collar on upside down.  The hole in the collar is not drilled in the center but close to center.  If you flip it over the plane will likely handle much better.  A look at a parts Manual sec 32-20-00 will help.

[Bob_Belville]

Hi Bob - I'll have to do some digging.  As I recall, I'd seen it on MS from earlier discussions (few years back).  I checked with Air-Mods (MSC) and they said that was correct.  The reason I began thinking about it was my tires looked quite flat at 30.  Turned out they were 6-ply and required the newer, higher, psi pressure.  It doesn't bother me if it is a few lbs. less but down at 30 and they are really soft and noticeably don't roll as well.

The mains were always 6 ply so that does not mean much.

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[Hank]

2 hours ago, Marauder said:

Since we are talking about nose wheels, do most of you hear any sounds when you cross over rough pavement. I have always heard a slight clunking sound that I attributed to the nose gear doors. Anyone else hear this?


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When it's bumpy, it sounds so clunky . . .

[Hank]

4 hours ago, rbridges said:

My c model has 49 psi stamped on the gear door. It came with a 6 ply when I bought it.

My C runs 30 psi on all tires, as shown in my Owners Manual. 

Memory says the mains are 6.00 x 6, the nose 5.00 x 5, but I don't recall the plies.

Edited March 27, 2017 by Hank

[Bob_Belville]

4 hours ago, rbridges said:

My c model has 49 psi stamped on the gear door. It came with a 6 ply when I bought it.

I doubt that that is right. Even if it is stamped.

[Bob_Belville]

9 minutes ago, Hank said:

My C runs 30 psi on all tires, as shown in my Owners Manual. 

Memory says the mains are 6.00 x 6, the nose 5.00 x 5, but I don't recall the plies.

Check the pdf file I posted above.

[Skates97]

49 minutes ago, Hank said:

When it's bumpy, it sounds so clunky . . .

I don't have any shimmy and it tracks straight as can be, but it does make a clunk sound when it's bumpy.

[XXX]

3 hours ago, Marauder said:

Since we are talking about nose wheels, do most of you hear any sounds when you cross over rough pavement. I have always heard a slight clunking sound that I attributed to the nose gear doors. Anyone else hear this?


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Nothing that I would attribute to the nose gear doors, but I do recall clunking. I'm not sure if it still does it after the rebuild. I'll try to pay attention next flight.

[XXX]

2 hours ago, FoxMike said:

Your mechanic may have put the collar on upside down.  The hole in the collar is not drilled in the center but close to center.  If you flip it over the plane will likely handle much better.  A look at a parts Manual sec 32-20-00 will help.

I'm pretty sure the collar only fit one way as the hole doesn't line up when it is flipped over. We did put the spacer in as called for by SB M20-202. I'm hoping the bounce will settle a bit as observed by @Antares.

 

 

 

[Cruiser]

Slow down! you are taxiing too fast. Bouncing will stop.

[rbridges]

1 hour ago, Bob_Belville said:

I doubt that that is right. Even if it is stamped.

I'll double check the paperwork. I had the 201 cowling added. I don't know when/why the increased psi started. Until this thread, I never knew there was a difference. 

[bonal]

28 minutes ago, Cruiser said:

Slow down! you are taxiing too fast. Bouncing will stop.

Agreed, I'm always pulling power to under 1000rpm and tapping the brakes it doesn't take much to start building too much speed I guess Mooneys just like to go fast

[rbridges]

3 minutes ago, bonal said:

Agreed, I'm always pulling power to under 1000rpm and tapping the brakes it doesn't take much to start building too much speed I guess Mooneys just like to go fast

I have to juggle throttle and brakes too. I think I read somewhere to maintain 1k rpm to keep oil splashed on the crank (in lycomings anyway.)

[takair]

My E clunks on sharp bumps and bounces when taxing too fast.  I always thought the clunk was some where on the main pivot bushing.  Almost everything is rebuilt, so not sure what else it could be.  Glad I'm not alone with that sound. I typically run around 32PSI and the nose tire looks kind of flat at that pressure.  The bounce is why you need to be extra careful on grass or bumps.  Use of elevator can help manage it, especially on bumpy takeoff or landing.  

[Flymac]

I hear some clunking as well '78 J over bumps occasionally.

Will (hopefully) soon get to test out new ride as well and see if I notice much bounce like you noticed....replaced 1997 biscuits all around!  They certainly didnt owe anymore time, but really werent badly bulged or hard.  LASAR rebuilt the nosegear and the discs certainly are pre-loaded to get the collar back on.

[Andy95W]

My M20C used to "clunk" fairly badly.  2 years ago, I replaced all of its bushings, bolts, and associated hardware.

It still clunks.

At this point I'm pretty sure it is the leg assembly moving up and down in the truss at the main steering pivot point.  Even properly shimmed, bushed, and torqued there is about 1/16" up and down play.

 

[RLCarter]

As the disks age the rubber gets compressed and becomes harder than Chinese arithmetic, with new disks the rubber is compressible, add that to the trailing link system and you get a "bobbing ride", just my theory......

[Marauder]

Good to "hear" I'm not the only Mooney clunking. With the GoPro camera technology available, I'm surprised someone hasn't put a camera in the wheel well and taxied around to see if they can find the source. My bet is on the gear doors.


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[Mooneymite]

My Mooney still has the original shock on the nose gear.  I'm wondering if it's primary purpose was to stop the bouncing?  Anyone still have theirs?

[Hank]

3 minutes ago, Mooneymite said:

My Mooney still has the original shock on the nose gear.  I'm wondering if it's primary purpose was to stop the bouncing?  Anyone still have theirs?

I have holes where mine used to be . . . Later models don't even have that.

[Mooneymite]

Just now, Hank said:

I have holes where mine used to be . . . Later models don't even have that.

Just about every older Mooney I see has had that shock removed.  Mine is an anomaly, but I'm wondering if having it still installed dampens the bouncing.  I'm guessing it does.

 

[Hank]

Your guessnis as good as mine.