Best way to Jack Up a Mooney to Change a Tire?

[cliffy]

Thought provoking wasn't it? 

Have had many very good friends over the years as FAA types. Have had a few as adversaries. One notable one in MDW twice about  737s I was flying for an airline. Most who did ramp checks were true gentlemen. Some were, shall we say, less than gentlemen. It all depends on whom you connect with. Actually, I always preferred an FAA person to give me my type rides. Always a better ride.  55 years in this game brings about numerous interactions that just a few years might not be able to comprehend. It also brings about caution in all dealings. 

As I've noted in other postings, fairings are covered in preventative maintenance.

I've also noted in previous posting (going back years here), to go ask the FSDO and see what they recommend. They hold all the cards. Or, as you haven't been around long enough to remember, it used to be - go to the GADO office and ask. 

[Yetti]

5 hours ago, cliffy said:

Do you or have you ever replaced the bolts and nuts with new that hold the wheel together? Can you visualize the stress on those bolts as the wheel hits the ground in a skid? Say after 50 years of service? Corrosion? Have you ever (or do you ever look for) seen broken wheel bolts missing there heads? I've seen many. Now you have a wheel being held together with just 2 bolts. How's the stress on that wheel now? 

Again, thought provoking ain't it?

 

It's not quite like that, all the stress is not on the bolts.   The majority of the stress is along the seams that the two wheel haves fit into.   The bolts only have the function of the side stress that would could pull the haves apart.  Which is not that much.

just a PP not a gineer

[RobertGary1]

5 hours ago, cliffy said:

To the above-  The MM specifically states to do FIVE gear retractions after any tire change! You shouldn't be doing the work if you don't have and follow the MM. LEGALLY you have to have the manual available when doing any maintenance. The FAA states that the manufacturers instructions must be followed. I know, I'm beating a dead horse but it bears repeating.

 

Not my manual. 

-Robert

[ShuRugal]

22 minutes ago, Yetti said:

It's not quite like that, all the stress is not on the bolts.   The majority of the stress is along the seams that the two wheel haves fit into.   The bolts only have the function of the side stress that would could pull the haves apart.  Which is not that much.

just a PP not a gineer

The clamping load on the bolt is going to be, far and away, the most significant force that those experience.  Parts diagram for the Cleavland wheels on my bird call for AN4-22A through bolts, which appear to be 1/4-28.  Not sure what SAE grad Mil-b-6812 specification translates to, but the assembly manual from Cleaveland says 75-90 in-lbs, which makes it at least grade 5, and gives us ~2,000 lbs clamping force.

In short, there's around 3 tons of clamping load holding those wheels together.  You could put the upper rim on a crane, and suspend the plane from the lower rim, and the bolts won't be what fail.

[cliffy]

Without the AN bolts the wheels would come apart with the side load. All the side load is transferred from the tire bead to the wheel flange and then to the inner hub and bolts. Think of the leverage arm along that path. The "ledge" on the inner half is not very large. The axle nut is not tight and doesn't provide clamping force to hold the wheel halves together. Uneven tightening of the bolts can lead to wheel failure (AC 43.13-1B, 9-18). The "J" model and all subsequent have the 5 retractions referenced in 32.40-02, after item 17 with reference to 43.13-1B, 9-18. (Sorry couldn't get the bold off)

So, all the wheel bolts that I have seen broken I guess weren't really there. I've seen them broken on Boeings also. 

Airframe (AN) Bolts

These fasteners are manufactured to rigorous quality control standards from raw material to final plating. They offer a combination of properties that are simply not available in SAE graded hardware. They have a tensile strength of 125,000 psi and a shear strength of 76,000 psi, but the most important difference is that they are not as brittle as SAE bolts. If they are overstressed, AN bolts will bend first rather than snapping.

[ShuRugal]

Without the AN bolts the wheels would come apart with the side load. All the side load is transferred from the tire bead to the wheel flange and then to the inner hub and bolts. Think of the leverage arm along that path. The "ledge" on the inner half is not very large. The axle nut is not tight and doesn't provide clamping force to hold the wheel halves together. Uneven tightening of the bolts can lead to wheel failure (AC 43.13-1B, 9-18). The "J" model and all subsequent have the 5 retractions referenced in 32.40-02, after item 17 with reference to 43.13-1B, 9-18. (Sorry couldn't get the bold off)

So, all the wheel bolts that I have seen broken I guess weren't really there. I've seen them broken on Boeings also. 

Airframe (AN) Bolts

These fasteners are manufactured to rigorous quality control standards from raw material to final plating. They offer a combination of properties that are simply not available in SAE graded hardware. They have a tensile strength of 125,000 psi and a shear strength of 76,000 psi, but the most important difference is that they are not as brittle as SAE bolts. If they are overstressed, AN bolts will bend first rather than snapping.

I'm not sure what you're getting at here. I'm not suggesting that the wheels would hold together without their through bolts, nor am I suggesting that bolts cannot be made to fail... This post seems to be attacking something, but I can't figure out what...

 

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[RobertGary1]

Is someone suggesting not using AN hardware? Seems like a silly savings and an easy fsdo catch. When I had my engine out the fsdo was all over my plane; oddly the engine was about the only thing they didn’t care about. 

-Robert

[Hank]

3 minutes ago, RobertGary1 said:

Is someone suggesting not using AN hardware? Seems like a silly savings and an easy fsdo catch. When I had my engine out the fsdo was all over my plane; oddly the engine was about the only thing they didn’t care about. 

-Robert

All I've seen is disagreement about the load on the wheel bolts. Then from nowhere is a discussion about the properties of AN-series bolts, with zero tie-in to the load actually placed on them. 

I'm still not sure what the relationship between behemoth Boeings breaking wheel bolts, and my tiny Mooney which probably grosses out around the weight of a single Boeing main wheel . . . . .

[Yetti]

The max side load is 2700 lbs. by the g force that is required for the tire to lose traction and start skidding.  Straight line side load is the tire PSI - the holding power of the tire sidewall.  Not that I would ever do it, but I don't think the hub would not go that far if the bolts were removed with 30 PSI on the tire.  Maybe a couple of feet.  Yes I know about split rims and tire cages.  My brain is tired from imagining all this stuff.

Edited March 24, 2018 by Yetti

[Mooneymite]

On 3/22/2018 at 10:22 PM, Gary0747 said:

What is the best way to jack up a single wheel to change a tire when wing point jacks are not available? 

I saw a Mooney parked at the FBO with a flat tire.  When the owner found it, he removed all the wheel retaining hardware, then asked the three linemen to lift the wing while he slid the wheel off the axle.  They used three large rubber chocks under the axle while the owner diappeared with the wheel to get a new tire.  About 90 minutes later, with the new tire mounted, the linemen lifted the wing while the owner slid the wheel onto the axle and resecured it... the Mooney disappeared into the sunset shortly thereafter.

I restrained myself from calling the linemen a bunch of jackpoints.

[HRM]

When in doubt, let the hangar fairies at it.

 

[ArtVandelay]

I saw a Mooney parked at the FBO with a flat tire.  When the owner found it, he removed all the wheel retaining hardware, then asked the three linemen to lift the wing while he slid the wheel off the axle.  They used three large rubber chocks under the axle while the owner diappeared with the wheel to get a new tire.  About 90 minutes later, with the new tire mounted, the linemen lifted the wing while the owner slid the wheel onto the axle and resecured it... the Mooney disappeared into the sunset shortly thereafter.
I restrained myself from calling the linemen a bunch of jackpoints.

I hoped he tipped them generously.