The International Cessna 170 Association

Hi folks,

As if I don't have enough troubles going on with old girl (been down for engine overhaul since early August... long story), we just found one of my main gear legs is loose!

I'm wondering what are the easiest and most secure methods to lift the airframe off the ground so we can investigate and repair whatever is going on in there? Even better, if you could provide a picture or two for me to replicate, that would be great.

Thanks in advance!

Should I assume there have been no replies to this because there have been similar (but not identical) requests recently?

I looked in the 100-series manual but it seems to describe a cradle that wedges onto the base of the gear legs themselves. That doesn't work if I'm looking to possibly pull one of the legs out for service...or maybe I'm misinterpreting?

-Kennet

The cradle in the 100 series manual is what you're looking for.
It contours the gearbox but doesn't wedge into the legs so they can be removed.

If it were me, I'd pick ip the plane by the motor and lower it onto the cradle at a height to take the weight off the legs.

If your engine mount is still attached you can lift it by the upper mount where it attaches to the firewall. (See the "Hoisting" Section of the Service Manual.)

Here's the section from the 100-series manual that I'm seeing. It sure looks to me like it wants you to wedge against the gear. Also, doesn't it block access to the holes underneath such that you couldn't reach the single nut on each gear leg?

I played around with hoisting by the mount using straps and an engine hoist this evening. I lifted from a lower point than where George suggested. I'll try the upper mount points next to see if it makes a difference in stability.

That jacking block is made to bear against the landing gear and to clear the fuselage, both points clearly stated on the drawing.

Kennet,
If you're going to be working on the main gear I think the support stand illustrated in fig. 19-1 might work better than the one that wedges between the gear.

I hadn't thought to look in the structural repair section.

Looks like a trip to the hardware store is in my future.

Thanks Gary!

I don't see a dimension for the webbing sag to the fuselage contour.

John

My mistake. I was talking about the wood block and thinking about the cradle with the strap.

Years ago I had my right main gear leg become loose so when taxing on grass I could hear a bump every time I hit a clump or a small hole. Checking I found the gear was moving backward or forward about 1/4 inch if I pushed on the tire. Turned out the lower shim inside the gearbox was cracked on one and broken on the second one. Replacing them cured the problem and I have had no issues since. Must have been 15 yrs ago. I'd venture that that is the cause of the problem unless the main attach nut has become loose. I lifted my plane via a come-a-long and a heavy parachute strap used for dropping cargo out of C-130's. Placed it just behind the main gear if I remember. Other methods are probably better.

bagarre wrote:...If it were me, I'd pick ip the plane by the motor and lower it onto the cradle at a height to take the weight off the legs.

Lift by the mount as close as possible to the firewall. DO NOT LIFT THE WHOLE AIRPLANE BY THE ENGINE LIFTING LUG! The sight of a case in the junk pile with a chunk broken out of the backbone will make a believer out of you.

I didn't pick up (pardon the pun) on that earlier... Yes, lifting the airplane by the "motor" is a particularly bad idea.
The 100 Series Service Manual is explicit on Hoisting instructions and recommends the upper engine mount near the firewall. Hopefully everyone working on these things has a copy of that inexpensive yet valuable manual.

Lucky for me, my mount is currently unobstructed since the engine is removed for overhaul. I'll pick it up by the upper mount locations at the firewall as everyone is suggesting and plan to build the cradle shown in the 100-series manual this weekend. If it looks good when I'm finished with it, I'll post a picture here.

As far as my loose gear leg, I'm hoping for the loose shim scenario. It seems the most likely from what I've seen so far without removing components.

Perhaps you might do what is pictured as I did on main gear change-out. Easily built with cheap materials and had the luxury of overhead rigging to the hangar beam which also steady the 2X4 frame structure using a come-a-long to do the initial lift. It was hung for several weeks like this with no problems even though we were doing extensive replacement of the corroded gear outer brackets with new P.Ponk brackets and beef-up kit. As far as lifting by the motor, most of the weight (emptied fuel tanks to make lighter) is actually divided between the cargo straps located on the lower lift struts as well as the motor. Only removed one side at a time so opposite gear still was in full contact with the floor and a 2X4 carefully placed on the upper wing strut (locked into the tie-down ring) to prevent repair side from moving. Certainly an unusual rig but worked extremely well. However, now that I have new knowledge from these posts, I would do the initial lift from the motor mounts as close to the firewall as possible next time and not the motor eye hook itself. See this post....http://www.cessna170.org/forums/viewtop ... 13#p121416