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Hangar ceiling mount

Swiss14A

Active Member
Hi guys

I am hoping to drain your brain for a solution to mount our RV14A to the hangar ceiling. In Switzerland hangar places are rare and hangars are packed with planes, wingtip to wingtip. The ceiling mount is a nice solution, keeping your aircraft away from others and avoiding damage when moving planes around...
The lift and mounting principle will look something like on that Legacy:

50792224072_a5ce998880_c.jpg


I have a hangar space now for my Vari Eze and intend to use it for the RV.

The main attach bracket will be on the main spar, looking something like that. I will exchange the close tolerance bolts to attach the spar with longer ones and install the bracket on the aft side. A hole in the upper wing root fairing will enable a long bolt to be installed into the bracket. There is a threaded, vertical hole in the bracket.



I checked various loadings. The main force will be on these two brackets, but I need a forward attach point for the remaining 150-ish kilograms, 330 lbs.



Thinking many options through and discussing with fellow builders I ended up with two options. Both will require two small holes for bolts through the upper cowling that I will eventually close with two small doors. And again there will be a threaded hole to attach a bolt from the lift.

Option A
Use the FF01400 engine mounts upper horizontal bars on the left and right side for two attach brackets bolted around the engine mount bars.


Of course the engine mount was not designed for a lifting force, but keeping in mind that it will be roughly 75kg per side (170 lbs) it is not a lot, even with a safety factor of 4...

Option B
Use the engine attach bolts (AN7) and attach two brackets.


Again, the bolts have not been designed for that load, although it is roughly the engine weight, it would almost kind of equal the load ;)

Any inputs and preferences?

Thanks in advance
Fabian
 
The Spar Is Close To the CG

Doubt if you'll find many qualified structural analysis engineers to comment, but please consider the center of gravity with respect to the main spar. It'll change with the fuel in the tanks and any possible cockpit or baggage that might be in the plane. My concern is that if the CG is aft of the main spar, the plane will tip backwards. Could you find a suitable attachment point well aft the spar, perhaps at the main gear location or even aft of that instead?

Dave
 
Couple thoughts:

In general, attaching to the engine mount tubes isn't what you want to do. They are designed for loads in tension or compression. Tension in the case of the ones you're considering. They probably shouldn't be loaded in bending. The engine mount cups seems like a better way to go. Where/how do the Legacy's front lift points attach?

Instead of using a threaded attachment for your lifting fitting, I'd use a clevis with a shear bolt or pin on all 4 connections.

Please follow-up with your final design and show a picture of your suspended RV!
 
Consider a propeller sling

You may consider a sling on the propeller. I do this to lift a Glasair. Jack pads on the wing spar at the tie down bolts provide the main lifting. The nose is lifted with a sling around the base of the propeller. It would save having to remove and store the upper cowling anytime the plane is hangared. I can send a picture if you like. The nose will be a small fraction of the total weight of the plane.
 
Sorry I’m no help with your structure questions, but I do recommend you hang the Vari Eze — your going to want quick access to the 14 when you get it flying. :D:D
 
Does everybody in Switzerland paint their planes red/white?
Good Luck with the project, keep us updated.
 
Not a structural Engineer but, I would question the ability of the ceiling joist and span to support the aircraft or multiple aircraft in your case first, then decide how best to lift up an individual aircraft. That latter question could be best decided by the CG location of the specific aircraft. Most hangers in the USA will not accept any more load on the ceiling , and don't forget snow load as being a significant load factor. Would hate to see a two or three airplane crash inside the hanger!!!

Most stacked storage options I have seen in the USA use a floor mounted hydraulic or winch lift with the ability to park a second plane below the first elevated one.
 
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The other obvious question is...

There's a nosegear RV suspended in the background. How does that guy (?) lift the airplane?
 
How about using a lifting platform? Roll the aircraft on to a square low-profile metal frame (devise a suitable chocking arrangement), attach the four overhead cables to the frame's four corners and lift away. The frame could be sized to accommodate a variety of wheel configurations.
 
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Does everybody in Switzerland paint their planes red/white?

Luckily no, those are only the most visible ones :D
We have quite a few RVs flying around here (same as for the virus :(, e.g. highest per capita) and plenty are yellow, blue or whatever.
And as I’m informed, the OP’s -14 won’t be any of those colors neither :cool:

Xcuse the thread drift Fab...
 
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What about a lift? I knew a guy that had 4 of them in his hangar. They worked really well and you don't have to worry about modifying the airframe.

http://armaerospace.com/

Any idea of the cost of these? I am trying to come up with a solution for potential floods. I think there was a maybe 2 feet during harvey, bought the house after. Also, would like more floor space either way.
 
Why not use the lift point on the engine?

That lift point is stressed for the weight of the engine and the lifting arrangement could require a bigger lifting force than the case was designed to hold. If the case fails, you just spent a LOT of money.
 
Aero Lift

They are not cheap but do a nice job of freeing up hangar space. They also come in handy when it's time to change from wheels fo floats.

I did have issues with the lift in the beginning, It would not work correctly for the RV10. The arms needed to be modified to accommodate the position of the wheel pants and keep the plane within the COG. The yellow platforms for the main wheels also needed to be widened to accommodate the wheel pants. Aero Lift was good about it and provided the re-designed arms at no additional cost.

If anyone is planning on using this for a RV10 and has questions of what needs to be ordered send me a private message.

Gary
 

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How about using a lifting platform? Roll the aircraft on to a square low-profile metal frame (devise a suitable chocking arrangement), attach the four overhead cables to the frame's four corners and lift away. The frame could be sized to accommodate a variety of wheel configurations.

Ding ding ding!! We have a winner.
 
Hi guys

Thanks so far for your replies and comments. I try to sum up some answers to questions:

The ceiling and lifts are strong enough to support the weight. As you can see in the picture it is a massive wood construction, made for the purpose to have all the lifts. Also the lifts slide out of the hangar before you lower the aircraft, so it is really a quick way of storing your aircraft :) that's why the Eze will be gone and the lift occupied by an RV :)

The RV7A in the background is swisseagle's :) He has a platform. Very nice and solid design and certainly my backup solution, should I fail to find a proper one. The main advantages of hanging the aircraft directly are:
- access to gears and tires
- more flexibility with aircraft below, because it is easier to circumnavigate a high vertical stab around three single gears of the aircraft on the ceiling, versus a platform which is blocking all possibilities
- smaller total weight on the crane
- and... personal preference :)

I have to check the Lancairs attach points. Certainly somewhere on the engine mount or firewall bolts...

Any inputs regarding the two options?

Thanks
Fabian

PS: No Dan, not many colours on our plane, but anyway still a while until painting :)
 
That lift point is stressed for the weight of the engine and the lifting arrangement could require a bigger lifting force than the case was designed to hold. If the case fails, you just spent a LOT of money.

I also made some calculations on this. Actually in my case it would be around 250 lbs on the lift point. But as Kyle pointed out, if the **** hits the fan, you split your engine case...
 
You may consider a sling on the propeller. I do this to lift a Glasair. Jack pads on the wing spar at the tie down bolts provide the main lifting. The nose is lifted with a sling around the base of the propeller. It would save having to remove and store the upper cowling anytime the plane is hangared. I can send a picture if you like. The nose will be a small fraction of the total weight of the plane.

Hei Skysailor. Could you post some pictures? Do you have any way of securing the slings, e.g. if the prop would turn slightly and a sling slides of... :eek:
I'll calculate the weight up front, but I guess still around 50kg/110lbs
 
Consider displacing the center lift backwards with a yoke with a saddle down to the propeller so that the nose is slightly higher regardless of fuel quantity.

The slight leveling pressure, nose down, won't over stress the engine mount.

FWIW
 
disclaimer: not a structure Engineer myself...

I had some thought about your problem. There are quite a few aircraft hanging in the hangars around here, and most solutions appear good enough. Good enough? Yes, meaning holding up and easy to install and remove :)

One problem you didn't mention, but worth consideration, is lateral balance, or rather imbalance... as you know there are 2 types of winch systems in use on your field, 2 and 3 pointers. Yours is a 2 pointer, which means you will have to balance the fuel in your tanks, or use additional weights on the lighter wing, to permit lifting your -14 in a wings level attitude.

I had a look a while ago at the system as used on another hanged Lancair Legacy (YMI), and remember the forward attach points on the engine mount/firewall structure, which I think is the best solution. One threaded tube each side accessible thru a small hole on the top cowling.

Now for the rear attach points... ideally a good distance behind the CG to improve stability.
Solution A (I don't have the -14 plans) would be some bar or threaded tube extending from the rear spar. Problem here could be insufficient lateral clearance of your cable/chain system to the sides of the fuse.
Solution B, is there any way to maybe reinforce and use the foot steps base as anchor? (again, no plans, no Engineer)
Solution C would be to use a sling, positioned on one or several bulkheads, maybe using a kind of sled made outta CFK or aluminum (also in your hangar, the yellow Votec is using something like this) to spread the load.
 

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If you use a sling, don't use those handy ubiquitous plastic connections. Use a bit of rope to go from the strap to a marine shackle, something like one of these. You can get them to carry the load and they are reliable.

Snap Shackle.jpg

Dave
 
follow up

Hi guys

as a follow up, this is how we did it in the end: one bracket at the engine mount (both sides) and one bracket as in the construction drawing earlier on the aft side of the main spar. Had to get longer close tolerance bolts of course, but got them from Genuine Aircraft Hardware Co.
Of course I calculated all possible c.g.'s. Works very well so far.

IMG_1586 by Fabian Hummel, on Flickr

IMG_0663 by Fabian Hummel, on Flickr

IMG_0668 by Fabian Hummel, on Flickr

IMG_1886 by Fabian Hummel, on Flickr

IMG_1887 by Fabian Hummel, on Flickr

IMG_6214 by Fabian Hummel, on Flickr

IMG_1862 by Fabian Hummel, on Flickr
 
I would like to see a video of lifting the RV sometime if possible. Very nice.
One concern on the front mounts. If I recall the engine mount bolt passes thru a larger bore pipe until it gets to the firewall and the washer that is welded to make the mount. Wouldn't that allow a bending moment on the firewall bolts?
 
I would like to see a video of lifting the RV sometime if possible. Very nice.
One concern on the front mounts. If I recall the engine mount bolt passes thru a larger bore pipe until it gets to the firewall and the washer that is welded to make the mount. Wouldn't that allow a bending moment on the firewall bolts?

I try to film it next time, if I remember it :) but it is not really spectacular, just very slow. We can control in/out and up/down.

You are right, there is a hollow „tube“ at the engine mount, and the bolt is not exactly centered, probably to account for tolerance during welding. A friend of ours produced two bushings to account for that. They keep the bolt from bending. Unfortunately I don‘t have a picture of that.
 
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Nice looking plane and it looks like a great solution to your situation.
Do you just unscrew the tie down bolts when you are ready to fly?

I think I may have gone for a lift but since you had the whole system there already, great job making it work. It looks easier to use than a lift too.
 
That's a slick solution all around, and beautiful plane. What do you use to plug the holes in the wings and cowl while flying?
 
Yes exactly, we just unscrew the rings (they are actually not tie down rings, but similar function with the appropriate rating to lift the weight) and leave them in the hangar. The advantage of hanging the plane instead of a putting it on a lift is, that it‘s a no brainer to change tires :)
Actually we leave the holes open. Wings are half an inch, the front ones even less. Front ones are covered by the canopy cover if we park outside. Both threaded holes underneath have drain holes for water…
 
building design

I’m not an aircraft structural engineer but I am a BUILDING structural engineer. Others have commented about the possible consideration for the (increased) loading on the roof structure. OP says his building is sufficient for it and this one does look like it could have been designed for such loading.
My expectation is that for buildings that are already designed for a significant snow load (such as northern US states) may be adequate, provided the snow load does not occur at the same time.
I don’t know about snow load requirements in Switzerland but, I would NOT expect a building that is located in any mid US or southern state to be adequate based on the ordinary building design parameters. Of course they CAN be designed for such loading but I would not expect it to be ordinary.
Still, that lift looks pretty sweet.
 
I’m not an aircraft structural engineer but I am a BUILDING structural engineer. Others have commented about the possible consideration for the (increased) loading on the roof structure. OP says his building is sufficient for it and this one does look like it could have been designed for such loading.
My expectation is that for buildings that are already designed for a significant snow load (such as northern US states) may be adequate, provided the snow load does not occur at the same time.
I don’t know about snow load requirements in Switzerland but, I would NOT expect a building that is located in any mid US or southern state to be adequate based on the ordinary building design parameters. Of course they CAN be designed for such loading but I would not expect it to be ordinary.
Still, that lift looks pretty sweet.

Well what I can says is that in Switzerland we also do have requirements for snow loads.
 
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