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RV-12 saw horse collapse

DonFromTX

Well Known Member
Since most everyone has had to park their 12 on sawhorses for the gear SB, this should provide some caution. I almost did the same, using old plastic sawhorses, at the last minute I bought some 1000 lb capacity steel ones. This is a friends build, it crashed when he was not even around it so he was not injured. No big damage to the airframe was reported either.
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YIKES!

Oh....:eek: that is just ugly.

When building there were so many times I would check recheck, and over engineer all the supporting stuff.

Even now when changing tires etc, padded 2x8 special U box for the tail, motorcycle lift under belly with a wooden padded box and then supports under each wing.

If i did that to my plane during the build....there wouldnt be enough beers in the fridge to make it ok.

Hope all is ok.
 
Disturbing photo

I'm using the very same sawhorses in my project. Because of this mishap, I intend to conduct a good FMEA scrutiny of them. Thanks for posting, Don. Maybe it will save others from a similar fate.
 
I am working on my wing spar and skeleton on those same sawhorses and just the other day I got paranoid and tied all the legs together to prevent this exact scenario. Won't build the fuse on these though, for sure.
 
That was the intended purpose of the post. Had I not had a trip scheduled to Harbor Freight that day for something else, mine would have been on the identical sawhorses.

I'm using the very same sawhorses in my project. Because of this mishap, I intend to conduct a good FMEA scrutiny of them. Thanks for posting, Don. Maybe it will save others from a similar fate.
 
Ouch! I'm doing the SB now. I back up the sawhorse on the side I'm working on with a Kevlar sling to a shop crane. I'm only removing one gear leg at any given time so if it drops the remaining gear catches one side and the sling supports the other.
 
Gotta Share This Story

....Even though it concerns a non-RV, it DOES involve a sawhorse.

I was changing the engine on my Cessna 180 at the Oxnard, CA airport. I decided to pull the landing gear off and have the legs magnafluxed. Home Depot at that time sold wooden sawhorses that they claimed were good for something like 2,500 pounds or so, and I bought one.

At the end of Sunday, the plane was resting on the sawhorse under the gearbox, with the landing gear and engine off, tailwheel on the ground. It wasn't too solid. We wedged the belly so that it wouldn't rock. The right wing overlapped a friend's Cessna 185. Another friend shook his head and said, "Man, if there's an earthquake, this place is history."

Well, that was the night of the Northridge earthquake. Even up the coast where I was staying then, it shook the cottage. Without thinking about downed bridges, I boogied on down to the hangar. It was completely intact. No damage at all. That wooden HD sawhorse did the job.

A few days later we flew the 185 out to look at the damage. It was like all over the place for maybe a hundred mile circle. Fresh cliffs in the hills, tarps over roofs in the Valley, bridges down. In fact, I later noticed some damage at my cottage 45 minutes up the coast in Carpenteria.

The sawhorse? Right now it's holding up the fuselage crate for my RV-3B. It's shown here when the kit was delivered.

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That's one sawhorse that has a job for as long as it wants.

Dave
 
I have the same set of saw horses in use in the garage now. They are rated for 500 lbs at 30". That engine wouldn't be close to 500 lbs, would it?
 
I used the short Burro brand wooden saw horses for my project. They worked great with no chance of collapsing. Also, using one of them and a couple of scissor jacks under the fuselage (and tying down the tail) I can jack up the plane. They are rated for a ton.
 
Nylon straps caution too.

Crashes can happen several ways even when no one is around. Never hang airplane parts from cheap ratchet straps where sunlight can reach the straps. I had to build a new elevator because mine fell about 10 feet when the strap dry rotted from the sun and came apart. It was a new strap when I hung the empennage and had never been wet. They came from Harbor Freight, BTW.
 
I settled for these, $32 at HF, and you can clip a coupon for 20 % off in most magazines. They do require about four inches cut from the bottom of the legs, but that took only a couple minutes with a hot saw. They are rated at 1000 lbs each, fold for storage, and are just the right length for an RV12 without alteration. I figured if I was going to have an RV12, then these would just be part of my maintenance supplies.
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Heavy Stand Page 1-9 MM

One option to buying some stands is to make the heavy stands shown on page 1-9 of the RV-12 Maintenance Manual.
Here is a dimensioned drawing:
IMG_0005-M.jpg


Parts cut to size:
CTT_4294-M.jpg


Finished stands:
CTT_4297-M.jpg


Fuselage on stands:
CTT_4320-M.jpg


If you can build an RV-12, these stands should be a breeze and are cheaper and much steadier than most hardware store horses and they are designed to fit the aircraft. They do not fold for storage and they therefore cannot fold and dump your fuselage.

Tony
 
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Me too!!!

I used the short Burro brand wooden saw horses for my project. They worked great with no chance of collapsing. Also, using one of them and a couple of scissor jacks under the fuselage (and tying down the tail) I can jack up the plane. They are rated for a ton.

The Burro brand are great. I've cut them down to make working on the fuselage much easier. Use them all the way through the canopy and panel work.

I don't mount the engine or LG until everything else possible is done. Too hard to work with the thing sitting high on the gear.

Burro's make it simple.
 
Gil, I've used the Black plastic ones you showed. They cracked under the weight of another project. I'd recommend using a brace across the legs on each end to prevent the legs from spreading and cracking the top plastic piece.
All the best,
Dave
 
Gil, I've used the Black plastic ones you showed. They cracked under the weight of another project. I'd recommend using a brace across the legs on each end to prevent the legs from spreading and cracking the top plastic piece.
All the best,
Dave

Yes, I added a cross brace for stiffness.

As far as cracking, the thick polystyrene does seem to hold up well to the AZ heat, unlike some other plastics. I have had many more failures with the folding plastic type.

I like them because they are easy to rebuild in different height for specific tasks...
 
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I finally took the time a few weeks ago to fabricate two sturdy wooden saw horses. Made them a few inches shorter but then added about 4 inches of layered card board and capped with carpet. No idea if they meet the 500lb load capacity test but with carpenters glue and lots of screws, they sure appear strong. (thanks Tony for the schematic above) Using new 2"X4"s but otherwise scrap lumber, whole project was only $20.

One has to be careful about the placement of the aft sawhorse if the fuel tank vent is installed - would be a PITA if the drain tube was inadvertently shoved back into the fuselage.
 
back to the op

Hope there is no engine damage. That crankshaft looks very close to the floor.
 
One option to buying some stands is to make the heavy stands shown on page 1-9 of the RV-12 Maintenance Manual.
Here is a dimensioned drawing:
IMG_0005-M.jpg


Parts cut to size:
CTT_4294-M.jpg


Finished stands:
CTT_4297-M.jpg


Fuselage on stands:
CTT_4320-M.jpg


If you can build an RV-12, these stands should be a breeze and are cheaper and much steadier than most hardware store horses and they are designed to fit the aircraft. They do not fold for storage and they therefore cannot fold and dump your fuselage.

Tony

Thanks Tony,

I'm probably missing something, but all I see on the referenced page to the MM is a grayed out picture of one already built. No dimensions.

I'm thankful you included the pictures!

Oh and I haven't seen straight 2x4's like that in over a decade! :(


Bob
 
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