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New biscuits, very bouncy nose


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Hello all, 

We just installed new donuts on the nose wheel along with a LASAR steering horn and a rebuilt nose truss. The steering is much more responsive and no play whatsoever.  There is no more shimmy right before rotation now. So overall a pretty noticeable improvement. What I am not happy about is how exaggerated every bump in the pavement feels. My plane bounces like a low rider on Sunset Blvd. 

Is this the way a Mooney is supposed to feel when taxiing? Anyone else have the same reaction after replacing their donuts?

Thank you in advance for your responses,

Steve

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52 minutes ago, Chupacabra said:

My plane bounces like a low rider on Sunset Blvd. 

Is this the way a Mooney is supposed to feel when taxiing? 

Dunno, but if that's the case you should pimp it out further. I'm picturing purple metallic paint and spinners on the wheels. Maybe a giant subwoofer in the baggage compartment. The Mooneys do ride low :lol:

I had my original pucks replaced after prebuy so have nothing to compare to. But the nose does oscillate a bit after hitting even a small bump.

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Thanks for the replies.

9 hours ago, Bob_Belville said:

You're driving a roadster and you'll feel the road more than in a Mercedes limo. But you might be sure the tires are not seriously over inflated...

Bob, Yes, I double checked . It's 49 PSI. Good call though.

 

4 hours ago, Hyett6420 said:

Ive just had ALL my pucks replaced.  She is noticeably smoother on the ground, yes she bounces, they ALL do, check out the video attached.  This is EGTR in the UK with its not quite so smooth pavement.  

If you hold the yoke back it reduces the bounce, also don't taxi fast.  

IMG_0174.MOV

Andrew, after watching your video I feel better. I guess that's the way they are supposed to ride on the ground. I thought the ride would be more cushioned because there is always talk of how worn out pucks will contribute to fuel tank leaks.

Nice video by the way. What a gorgeous Mooney!

51 minutes ago, rbridges said:

It makes sense to me. Kind of how a car has a softer ride when the shocks are bad. 

I did the steering horn swap, and boy was I glad to get rid of the shimmy. 

The steering horn made a huge difference. Highly recommend to anyone with shimmy or sloppy steering.

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12 minutes ago, Chupacabra said:

30 mains and 49 on the nose. I wonder why the difference? It would seem the weight would be the same up front.

When they stretched the plane 10" I suspect they had to move the engine, which is the same IO360A1A, further forward to control the CG which put more weight on the nose gear. But I'm just guessing. The "arm" for my oil is -6.5" and the starter is -18". If you have your original W&B from the factory it might be interesting to see how much weight was on the nose wheel. (I don't have that info here for mine but I'll get it out of the plane unless someone can 'splain it to us before I get out there.) 

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Just now, Bob_Belville said:

When they stretched the plane 10" I suspect they had to move the engine, which is the same IO360A1A, further forward to control the CG which put more weight on the nose gear. But I'm just guessing. The "arm" for my oil is -6.5" and the starter is -18". If you have your original W&B from the factory it might be interesting to see how much weight was on the nose wheel. (I don''t have that info here for mine but I'll get it out of the plane unless someone can 'splain it to us before I get out there.) 

Bob, I just read in an older post that when Mooney started using a 6 ply tire on the nose, they upped the PSI to 49 from 30. Do you know if you have a 6 ply or a 4 ply n the nose? Mine is a 6.

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Just now, Chupacabra said:

Bob, I just read in an older post that when Mooney started using a 6 ply tire on the nose, they upped the PSI to 49 from 30. Do you know if you have a 6 ply or a 4 ply n the nose? Mine is a 6.

4 ply. But I suppose the heavier tire was to handle heavier loads. Our mains are 6 ply and inflated to 30 psi.

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5 hours ago, Chupacabra said:

Bob, I just read in an older post that when Mooney started using a 6 ply tire on the nose, they upped the PSI to 49 from 30. Do you know if you have a 6 ply or a 4 ply n the nose? Mine is a 6.

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

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49 minutes ago, Lance Keve said:

And I believe 6-ply mains would be 42psi, up from 30.  Mine are 6-ply all around and I run 42 mains, 49, nose.

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

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6 hours ago, Bob_Belville said:

When they stretched the plane 10" I suspect they had to move the engine, which is the same IO360A1A, further forward to control the CG which put more weight on the nose gear. But I'm just guessing. The "arm" for my oil is -6.5" and the starter is -18". If you have your original W&B from the factory it might be interesting to see how much weight was on the nose wheel. (I don't have that info here for mine but I'll get it out of the plane unless someone can 'splain it to us before I get out there.) 

I am 99.99% sure that the station of the engine is the same on all four cylinder metal Mooneys regardless of model. The cage is the same which is what the motor mount is fastened to.  The motor mount part number is the same for the E and the F (the weight difference between the E and the F is just 40lbs). The C and D share a different part number. My IPC does not include the G model, but I'd bet it uses the same mount as the C/D model.  Interestingly enough, the elevator travel is different for the mid bodies of the short (at least it was for the early birds).

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From the TCDS:

For M20E, datum is the centerline of the nose gear support bolts and is fuselage station 0.0. The Leading Edge of the wing at wing station 59.25 is 33.00 inches aft of fuselage station 0.00.

For M20F, datum is 5.00 inches aft of the centerline of the nose gear support bolts and is fuselage station 0.00. The Leading Edge of the wing at wing station +59.25 is 33.00 inches aft of fuselage station 0.00.

 

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1 hour ago, Lance Keve said:

And I believe 6-ply mains would be 42psi, up from 30.  Mine are 6-ply all around and I run 42 mains, 49, nose.

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

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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?


Sent from my iPhone using Tapatalk Pro

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7 minutes ago, mooniac15u said:

From the TCDS:

For M20E, datum is the centerline of the nose gear support bolts and is fuselage station 0.0. The Leading Edge of the wing at wing station 59.25 is 33.00 inches aft of fuselage station 0.00.

For M20F, datum is 5.00 inches aft of the centerline of the nose gear support bolts and is fuselage station 0.00. The Leading Edge of the wing at wing station +59.25 is 33.00 inches aft of fuselage station 0.00.

 

Then there is 5" more "wheel base" and the nose wheel does support more weight in the F than the E.

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