Jack it up

[MooneyBob]

Looking for some ideas.

1.What people use to weight down the back of the M20J ( or any other plane) to put it on the jacks in order to do some maintenance on the landing gear? How much weight does it take?

How much up the jacks have to travel in order to lift the wheels off the ground.

2. Any tricks or anything I have to be aware of when changing tires?

Thanks.

BTW, I have bought EZ tow today for $200. Very happy.

[MB65E]

I wouldn't load the tail with anything. Get a small step ladder, put it under the tail, then jack the wings up. Finally to take the nose off the ground, jack the nose up with an engine hoist bringing the tail in contact with said small ladder. Don't load the fuselage , but just enough so it does not teeter on the main jacks fwd/aft.

-matt

[MooneyBob]

I meant to chain the tail to the weight on the ground through the tie down eye. I have seen mechanics do that.

[MB65E]

Some say that tie down ring was never designed to hold the weight of the tail. There has been some heated debate here in the past. I personally don't do it and find it easier to use the hoist thank to lug a tail stand filled with cement around.

-Matt

[Piloto]

I use 2x4 rear stand that attach to a bolt on the floor and the tie down ring. Easy to set up, remove and store.

José

[Hank]

I've seen people use a galvanized wash tub full of cement. Screw some wheels into the bottom, and fabricate something to hold the eyebolt in place, then fill the tub with cement. Maybe get an eyebolt with a long threaded section (4" or more) and bend it for better grip in the cement? It's not really hard to push around, and makes a nice place to set tail inspection panels, screws, etc., while in use.

Mooney sent out a revised SB around 2010 suggesting that this should not be done. Apparently they want to sell a lot of engine hoists! The same instructions also recommend not using a propellor jack. Apparently someone thinks both are unsafe after fifty-plus years' use on Mooneys worldwide. But what do I know? I'm just a PPL.

[PTK]

Mooney SI M20-114 outlines proper jacking procedure. It involves using an A frame with chain hoist on the engine lift points. It's a lot easier to tie a cement bucket on the tail but not what Mooney wants us to do!

I will not jack my airplane by weighing down the tail. But then again I will not move it around by the prop either!

http://www.mooney.com/wp-content/uploads/2014/03/m20-114.pdf

[Hank]

Mooney SI M20-114 outlines proper jacking procedure. It involved using an A frame with chain hoist on the engine lift points. It's a lot easier to tie a cement bucket on the tail but not what Mooney wants us to do!

I will not jack my airplane by weighing down the tail.

It's such a shame, Peter, that you bought a used aircraft that had been mistreated like this all it's life until that SB was issued recently . . .

[PTK]

Yeah Jim, call me weird!

It's one thing when the airplane is flying and a totally different thing when sitting on the ground!

Two totally different animals!

[PTK]

It's such a shame, Peter, that you bought a used aircraft that had been mistreated like this all it's life until that SB was issued recently . . .

[Guest]

There is no safe method, tail tie down rings are not strong enough to hold the tail down, but are strong enough to tie down in a wind storm. Propeller jacks will damage the blade bearings. I've seen a crankcase cracked from using the lift ring to support the engine and plane.

Personally I've lifted a Piper Cherokee by the tail tie down ring and its 4 #10 screws after it was rolled in a ball in a wind storm. The little screw held with no signs of damage to the skin with the entire weight of the plane hanging from it.

Clarence

[Mooneymite]

Ever since that SB came out, I've been very reticent to pull back on the yoke to lift the nose off the ground for takeoff.

I sure don't want the tail falling off during a critical phase of flight.

I now use an engine hoist to set the proper takeoff attitude, but getting the dang thing off during takeoff roll has been a bitch...especially on our turf runway.

[Piloto]

With the mains on the ground it takes two 170 pounds guys leaning on the stabilator to lift the nose off the ground. Less when on jacks. If you feel this is too much force to apply to the tail don't fly the plane because this is the same force in flight and three times in turbulence.

José

[aerohawk]

Engine hoist only cost a couple hundred, seems like cheap insurance to me

[N201MKTurbo]

When I got my hanger in 1993 the first thing I did was go to the Home Depot and buy the biggest lead anchor and comparable eyebolt I could find. I spent about two hours drilling through the very thick concrete with lots of very hard rock. It hasn't come loose yet and I've never seen any indication of dammage to the Mooney or the floor. Just be careful when climbing in and out of the plane while on jacks. I think that is the most abusive thing you can do to a Mooney on jacks.

[Bob_Belville]

I built this, copying one my A&P uses on various planes. As mentioned above, there is at least one long thread on this topic from a couple of years ago. The Mooney SI is discussed. It was initiated in order to communicate a Lycoming SB(?) which warned about using prop stands. We never agreed as to whether Mooney was recommending against the tail hold down techniques which are very common practice.

[StinkBug]

Depending on what you're doing to the plane may give you different options. For just changing a tire or doing other work that doesn't require swinging the gear you don't need the whole plane off the ground. When I changed my main gear tire a couple months ago I simply made a long extension for my regular floor jack that I use for cars in my shop, and a little conical seat for it to index onto that bolted in place of the tie down ring so it couldn't slide out of place. Couple pumps of the handle and the tire was off the ground. When I need to change the nose gear tire I'll probably fab up something that slides into the open tube of the truss to do the same thing. 

[PTK]

I'm amazed at the resistance to change! It's like trying to teach old dogs new tricks!

To me it doesn't matter how it's been done before or for how long or why they decided to change it.

This is how Mooney wants us to do it going forward. It may be new engineers saw things differently and decided this procedure is better done this way. It could very well be that they are not comfortable with the multiple moments and the moment arms of the forces developed when weighing down the tail.

I don't know and certainly not going to argue with them!

I'm just happy it's just an SI and they didn't issue an AD to check the tail!

And this argument that the tail is so strong to lift the nose on takeoff etc etc, I'm not sure is relevant when all that weight is concentrated on the tail tiedown with clumsy humans jumping on the wings in and out to swing the gear.

To me that's as relevant as the prop argument. The prop is strong enough for flight therefore it can be used to pull/push the plane on the ground. This right in the face of McCauley who, emphatically, says don't do it!

I don't see the connection of either argument frankly!

[DS1980]

It makes me wonder what else Mooney pilots use as not designed.

Do they use their self-propelled lawnmower as a car?

Toaster as a space heater?

Bars of gold as paperweights?

 

I'm sure these sound ridiculous!

 

Name something you did 40 years ago you do the same way now.

[cliffy]

I'd like to see the difference in "pull" between a 4 cylinder Mooney and a 6 cylinder Mooney on the tail ring

as the nose wheel clears the ground. I suspect the forces are much higher even considering the longer arm of

the long bodies but I could be wrong.

How many tail rings have failed while on the jacks?

What kind of "damage" has been encoured by using the tail ring?

How many failed tail rings were compromised by having contact with the ground while flying?

How many of the failed rings were examined to determine why it failed?

Is there emperical data to support the acertion that the tail ring is not able to do the job

even after doing it for more than 50 years?

Or is the SI just drawn up from speculation or as CYA?

How do you lift from the engine lifting ring on a "dog house" vintage Mooney?

What if there is no lifting ring?

Just asking questions I haven't heard asked or answered yet.

[MB65E]

Who knows, I just wrap the engine biscuits with a strap and then use the hoist. I don't like pulling on the case except for engine weight, plus the dog house needs to come off. Some have told me they creat an inspection panel for the dog house. An inspection panel for an inspection panel. Lol.

I just like how stable the airplane feels when mains are jacked, nose is hoisted and the tail is supported by a small step ladder.

-Matt

[Bob_Belville]

I'd be interested in seeing some actual engineering data. The tail tie down ring surely has been engineered to sustain significant forces when being used as intended to secure the plane in wind gusts if not tornadoes. Where does the greatest load on the tail ring of the jacked up airplane fit in the design limits of the hold down specs.

 

I am convinced the SI from Mooney was really not a condemnation of the tail tie down procedure as it was a response to the Lycoming warning re prop yokes.  

[Hank]

 

Name something you did 40 years ago you do the same way now.

I still eat my cereal with a spoon, cut my meat before eating, read under a lamp without glasses and lie down to rest.

Seriously, Mooney just made a legal CYA move to protect themselves from a common A&P practice. I wasn't flying 40 years ago, still being in elementary school, but I'd guess that many aircraft service procedures have changed very little since then. Most have. I need to change, as servicing a magneto built to a 50 year old design can change very little (remove from engine, open up, replace worn/broken parts, reassemble, remount).

The way I jack up my car has changed, because the cars have changed. If I was to work on another 1976 Chevy truck, I'd jack it up the same way, but the frame and suspension components on the Ranger are different and require different methods.

[Bob_Belville]

I still eat my cereal with a spoon, cut my meat before eating, read under a lamp without glasses and lie down to rest.

Seriously, Mooney just made a legal CYA move to protect themselves from a common A&P practice. I wasn't flying 40 years ago, still being in elementary school, but I'd guess that many aircraft service procedures have changed very little since then. Most have. I need to change, as servicing a magneto built to a 50 year old design can change very little (remove from engine, open up, replace worn/broken parts, reassemble, remount).

The way I jack up my car has changed, because the cars have changed. If I was to work on another 1976 Chevy truck, I'd jack it up the same way, but the frame and suspension components on the Ranger are different and require different methods.

 

I was flying (more than) 40 years ago (GPS is way cooler than ADF). 

 

And I was working on my '66E almost that far back. We do have some clever tools today to made a few tasks easier but much is the same. 

[Guest]

I'd be interested in seeing some actual engineering data. The tail tie down ring surely has been engineered to sustain significant forces when being used as intended to secure the plane in wind gusts if not tornadoes. Where does the greatest load on the tail ring of the jacked up airplane fit in the design limits of the hold down specs.

 

I am convinced the SI from Mooney was really not a condemnation of the tail tie down procedure as it was a response to the Lycoming warning re prop yokes.

I've emailed Lycoming to ask their opinion on jacking/ lifting the nose of a Mooney by the lift ring as shown in the S/I. So far no reply from them.

I'll ask during Oshkosh.

Clarence