tail tiedown weight

[bonal]

Thanks Ron 

[RLCarter]

If you remove the engine completely as with most single engine aircraft the tail WILL hit the ground, by lifting from the engine (while attached) you are actually lifting less than the engine weighs which is putting less strain on the mounting attach hardware than it has when just sitting in the hangar. Most A&P’s have been weighing the tails down and/or using a prop stands on various aircraft for years with no issues. I’m not sure what prompted Mooney to publish SI M20-114 but they did, so that is the procedure that I follow. What I find odd are the ones that think only MSC’s can work on their birds but neither the owner or the A&P follow the current protocol for lifting the aircraft. Two things to think about, 1) The FAR’s state you have to follow the Manufactures recommended procedures, so are you in violation? 2) You or someone doesn’t follow SI M20-114 and the aircraft falls off the jacks or gets damaged in some way, does the insurance have to pay?

[Guest]

In my experience not all Mooney's will fall on their tail with the engine removed, some are actually balanced.  I would think that if the shop working on your plane dropped or damaged it, their shop insurance would cover the repairs.  Assuming that they have insurance, a good question for the mobile mechanic.

Clarence

[HRM]

11 hours ago, RLCarter said:

I’m not sure what prompted Mooney to publish SI M20-114... 

This is the operative phrase here.

I conclude it was a CYA to CYA.

Mooney issued it because it was a "Here's your sign!" phenomena and the SI describes a 'safer' procedure. This covers them in the same way that all those stickers on a ladder and my favorite "Don't use while showering" on hair dryers does.

Generally insurance covers stupid (the source of many accidents) regardless of how they occur unless blatantly intentional.

I imagine if the tail came off in flight and the Feds knew you to be a notorious tail-weigher they might do something to you, but then again, there wouldn't be much left to do anything to.

[M20F-1968]

The use of the tail weight alone is not recommended.  I have a tail weight with an adjustable vertical arm with a hardwood block into which the tail hook fits tightly.  I hold the engine with a 2000 lb engine hoist with a hook.  For additional stability I use the tail weight and hardwood block and the airplane is very stable with the 4 points controlled.

John Breda

[Bob_Belville]

Just now, M20F-1968 said:

The use of the tail weight alone is not recommended. 

John Breda

By whom? Not by anyone? I recommend it? But not "alone", I think you'll need a set of wing jacks. 

[M20F-1968]

There I go again - assuming that the obvious is understood. 

John Breda

[MisfitSELF]

Any recommendations on an A-frame or engine hoist to use for Jacking (and even engine removal).  I've seen them range from $500 to >$5000.  Of course if the $500 one works that's what I'd want to get.

 

Bruce

[Bob_Belville]

11 minutes ago, bluehighwayflyer said:

I think my engine hoist cost $100 at Harbour Freight 11 years ago. It will slowly leak down if I leave weight on it for a long period of time whereas my higher quality wing jacks from The Jack House will not, but this has never really been a problem as I would never leave a load on any of them for a long period of time anyway.  

Jim

There's a 2 ton "foldable shop crane" in the latest Harbor Freight mailer for $179.99 that is lighter than industrial grade but ought to work. Boom extends out to about 5', height adjusts from about 6' to about 7-1/2'.

[N6758N]

I'd love to see if anyone could provide real evidence proving using a tail weight alone causes any kind of damage, particularly on a short body. 

[RLCarter]

I built my own jacks, A-frame and tail stand, jacks can be pinned at 1.5" increments and no fear of bleeding down. A-frame uses a chain hoist so it can't bleed down, tail stand to firm everything up. Spent somewhere around $350.00 and a weekend cutting & welding, will try and get some pics up tonight, I also have drawing/plans if needed

[tigers2007]

There's a 2 ton "foldable shop crane" in the latest Harbor Freight mailer for $179.99 that is lighter than industrial grade but ought to work. Boom extends out to about 5', height adjusts from about 6' to about 7-1/2'.

Look for their perpetual coupons. I bought my first one for $89 20 years ago and bought a second one last year for $99 with the coupon last year. Harbor Fright is turning into Best Buy - only things worth buying are when they are "on sale" otherwise they charge 3x the price.


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[Sabremech]

A little birdie told me the concern was with the hardware attaching the tail tie down to the aircraft. I checked mine and have gone back to using my tail tie down weight. 

[Jerry Pressley]

am I correct in assuming that while the plane is flying, the tail holds the nose up?  even when the plane is in awkward positions the pressure is on the middle (tailcone)?   seems like there is more pressure on the tail when the nose is abruptly pulled up than would be by tying down the tail on jacks.  No?

 

[carusoam]

So, the total forces are the same, but the distribution is completely different... air pressure is so nicely distributed.

Following this thought...

1) you can hold the tail down with a bag of big rocks, but the sheet metal may be damaged by it...

2) you can hold the tail down by pulling on the tie down ring, but if the threads have been cross threaded or worn over the years, it may not hold the expected amount.  Whatever the tail tiedown ring was designed to withstand has very little to do with how much the tail plane forces are.  

3) the tail structure in its design and construction can handle the forces, but if it no longer matches the original design or its construction has changed... age and wear have a bearing on this... put in an improper tail bolt from Home Depot...

4) In our planes, gravity and tail tiedowns are operating in the same direction, in the hangar, and in flight.  Not so, for canards...

So many things come down to the details followed while doing the work.  A belt and suspenders approach may actually make sense.

PP thoughts only, not a mechanic...

Best regards,

-a-

[Guest]

If there were failures while using the tail tie down, I would guess that the bolts were damaged or the tie down itself was ground thin from a tail strike.

Clarence

[Jerry Pressley]

who in mooney said not to tie down the tail for lifting?  In later life Bill Wheat was not as informative as earlier.  Initially if you needed advice on how to do something out of the ordinary He had a reasonable Solution.  Later nothing was ever approved.  I knew him for lots of years (my first mooney was a woodwing just after the B come out)  and dearly loved the guy but as with all of us, including myself now, we are not as sharp when older. He as the man who showed me how to jack a Mooney .  

[RLCarter]

No sure but here is the document they issued M20-114

[Hank]

I like the way it says, "DO NOT leave tie down rings installed during flight," as if it could cause an accident. Mine come out every year at annual, then go right back in. In ten years, they've never even been loose . . . . Must have hired a new lawyer in 2008, maybe Chicken Little's son?  

[Jerry Pressley]

Bill Wheats directive.   a salvage operator I know pulled the lift point u along with a chunk of the case out of a Lycoming by trying to lift the plane during a salvage retrieval.   Don't think Mooney thought this one out very well.

 

[Bob_Belville]

Thanks to those who recently resurrected this old thread that I started, really as a cheap bas*ard brag. I had to go back and refresh my memory through 4 pages of posts. I'd forgotten how much fun it was! 

Jerry's last post ought to seal the fate of the advocates for engine hoists. So... make sure the tail tie down ring is sound and use a tail weight that stabilizes the tail vertically - up and down.

[outermarker]

It seems that there are two separate issues being blending here.

1. There is the aircraft jacking procedure, Mooney SI M20-114.

2. The groups "common sense" procedure to stabilizing the aircraft AFTER it has been lifted.

As someone who wants to acquire the tools to lift and stabilize my aircraft, this thread has been a good read.

I’d like to see more photos and links to where I can buy the things I need to buy. I’ll find a welder for what needs to be welded.

Thanks!

[Prior owner]

Nothing needs to be welded, unless you are going to fabricate your own wing jacks.. A portable shop crane such as one from HF works great for the nose- remove the upper engine cowling and dog house cover and hook into the engine lifting eye.

Lifting Mooney nose from lift eye

[Bob_Belville]

1 hour ago, outermarker said:

It seems that there are two separate issues being blending here.

1. There is the aircraft jacking procedure, Mooney SI M20-114.

2. The groups "common sense" procedure to stabilizing the aircraft AFTER it has been lifted.

As someone who wants to acquire the tools to lift and stabilize my aircraft, this thread has been a good read.

I’d like to see more photos and links to where I can buy the things I need to buy. I’ll find a welder for what needs to be welded.

Thanks!

In the very first post when I started this thread I listed the items I used to build a tail tie down tub.

[EricJ]

For those inclined to use a tail weight for gear swings, how much weight is sufficient for a short- or mid-body Mooney?    I've seen 160-250 lbs mentioned.    I'm in the process of planning putting one together and am trying to sort out how much is enough.   Right now I'm shooting for 200 lbs, but less would obviously make it easier.

I'd not have thought that keeping all those old brake rotors and flywheels around would pay off...