Greg:
Anyone in the So. Cal. area have a Jack/Tail stand I can borrow for awhile during my engine change? The base (March) will not allow a fifty gallon drum to sit under the aircraft while on the ramp. I guess it would be an eye sore.
Editor:
You can make an inexpensive tailstand out of a small galvanized wash tub and concrete. The washtub handles make it easier for two people to move. Get a good quality tub from a farm supply, not a hardware store junker. Some people like to have rollers under the tub, but I don’t. It reduces the security and stability of the plane when it is on jacks, unless they are very expensive casters that can be locked. NOTE: There are kits sold for this purpose. I have yet to see one that wasn’t very flimsy, with a poor grade of tub and a loosely-fitted thinwall tube arrangement that allowed the plane to rattle around on the stand while jacked. You are far better off making your own.
Use two sizes of galvanized pipe that slide inside one another; I seem to recall that the smaller pipe is one inch and the larger is one and one-quarter inch (pipe sizes, not tape measure sizes). You can get the pipe lengths cut someplace like Lowes, and have them left unthreaded. The threads won’t hurt; they just rust more easily and you don’t need them. You put a bolt (or threaded fitting) on the bottom of the large piece so it can’t pull out of the concrete. Cut a notch in the top of the small pipe that will straddle your tail hook, drill a hole through the resulting tab, and smooth all the edges before spraying it with cold galvanizing spray paint. The tabs and hole should be designed so that when the tabs straddle the tie-down ring and a 3/8″ bolt is slid in place, the plane cannot go up nor down, and the fuselage doesn’t hit the edges of the pipe. This is easier than it sounds to make, with a hacksaw and files.
Drill a series of holes through the part of the large pipe that protrudes from the concrete about a foot. Space the holes about two inches apart, with the first one about a half-inch below the top of the pipe. Drill matching holes in the smaller pipe, about one and one-quarter inches apart, starting at least three inches from the bottom of the small pipe. You can measure under your tail hook to get the best pipe lengths. The ideal is to have the small pipe about two or three inches longer than the big pipe, so it can’t get lost when dropped into the big one. You want to push a piece of firm rubber into the bottom of the big pipe, to cushion the small one when it is dropped. The reason for the different hole spacings is to make sure that there will be a number of possible different heights depending on the holes used, and not just in half-inch or one-inch increments.
You’ll need two bolts that are at least Grade Five, long enough so that the unthreaded portion fills the bearing areas; the threads should only be outside the bearing areas. Grade Eight will be more wear and corrosion resistant, and more resistant to thread damage, if you wish to spend an extra buck or two on it. You can make pipe bolt usage easier by bending a large flat washer up across the bolt head to make finger tabs; grind a starting taper on the threaded end; and use a large wing nut. There probably won’t be room for this in the tiedown ring, so just taper the starting threads and make sure that the nut is easy to spin on by hand. All the pipe and hardware can be sprayed with cold galvanize spray for corrosion resistance. LPS makes the best type, in my opinion, if you can find it; but there are other more common brands available at Lowes, etc.
You’ll want to make certain that the big pipe is vertical, and sealed against the bottom, when you put in the concrete. I doubt you will need more than a couple of 80-pound bags of mix, but you can always add another bag as long as you don’t get too small a tub. Oddly enough, I have had to add weight to use these stands on homebuilt planes, due to their short fuselage. One simple and neat way to add a small amount of weight for “fine tuning” is to go to a salvage or discount store that sells used stuff, and pick up one or two large weightlifting weights. They can slide down over the center pipe; just make sure that the center hole is large enough before you buy them. Making the stand much heavier than needed just makes it harder to move around.
The detail makes this sound complicated, but you can easily make a good and inexpensive tailstand in less than a day.
Wes Knettle:
Simply put, what is needed is a short post to support the weight of the tail when there is no engine on the front. Just go to your local welding shop and have them take a 24″ square sheet of 1/8″ plate steel. Lay it flat on the welding table. The take a piece of 1 1/2″ square steel tube about 3/32″ to 1/8″ wall thickness and 24″ long. Weld one end to the center of the plate. Make a vertical notch in the top wide enough for your tail tie down to fit in. The drill a 5/16″ hole horizontally through the notch are so when you slip the slotted area up on your tail tie down you can slide a 5/16″ bolt through the hole and the tie down. The stand will now hang loosely from your tail tie down until you remove the engine at which point she’ll be firmly planted on the ground. Make sure the notch in the square tube is not so deep it allows the two tangs of the tube to touch the tailcone skin.
Now this stand can also be use to hold the tail down by laying four 75
pound sand bags on it, and then you can jack the wing points and get all
three gear off for gear or tire work.
Remind your welder the weld joint should be able to handle 2000 pounds
pushing down or pulling up on the square tube.