LSA Tail Stand

Home shop machinist.

A tail stand is a useful accessory for tri-gear owners who regularly access
the tail boom innards, be it for annual ELT inspections or to check control riggings. The little fin to the right of the stand is the transponder antenna.

I decided I needed a tail stand after my transponder inspection last spring. A normal transponder inspection is pretty basic: Turn on the avionics and, after everything boots up, a technician walks around the airplane with a fancy (and expensive) gizmo that measures both the content and output signal strength of your transponder. If all goes well, you get a logbook entry, pay and go home. Other than it being the first time at a new shop (Accurate Aero in Minden, Nevada), I expected the procedure to be routine.

This time around my transponder output was low—way below the required level. This was a surprise because I thought my system was hunky-dory. In fact, just before the inspection, I had downloaded an FAA public ADS-B performance report (PAPR) from a recent flight. It showed no red flags or failure indications. To quote the FAA’s website: “PAPR data provides information on the performance of an aircraft’s ADS-B system for a specific flight and will verify proper ADS-B system operation or identify specific parameters received by the FAA’s ground system which failed to comply with established standards.” The PAPR report, however, does not count as a transponder inspection. It only reports what the system picked up on the specific flight in question and does not measure or confirm the transponder signal strength.

The 1-inch-round (left) and ¾-inch-square (right) tubes were sawed to length with the aid of a Park Tool saw guide. You can find this handy tool (or one like it) at your local bicycle shop.
A digital angle finder (left) was used to set the leg angle for mitering with the 1-inch hole saw (right).

I wasn’t sure how the guys at Accurate Aero would react. I’ve heard that some avionics shops don’t like dealing with Experimental/Amateur-Built aircraft. Pull the panel in a certified aircraft and you’ll find all the wiring neatly organized. Pull the panel in an Experimental and there’s a 50-50 chance it will look like a spaghetti bowl of wires instead of resembling a professionally wired certified plane (the latter being the standard of KITPLANES® subscribers/builders, right?).

A machinist square was used to transfer the miter position to each subsequent leg (left). After all three legs were mitered, a square was used to verify the lengths were equal (right).
The mill head was tilted (left) to make the miters for the feet in the ends of the legs. Note that all three legs were batch milled to maintain equal length (right).
Using the same tilt setup of the mill head, a miter was cut on one end of each of the 3/8-inch leg braces.

I had to give it up for the crew at Accurate Aero! After double-checking their equipment, they brought out their head guy, Mario Filice, who suggested a few quick checks to see if they could determine the issue. First, they pulled the transponder from the tray (thank you Garmin for making that easy) and plugged in a “known-good” unit from their shop. Same result. Next, they checked the connections from the transponder to the Garmin GDL 82 ADS-B unit and from the GDL 82 to the antenna. For that, I had to crawl into the tail boom to disconnect the coaxial from the antenna. But not before having someone “spot the tail” to keep it from crashing down on the pavement. Like most lightweight tri-gear aircraft, on mine, you can easily lift the nose gear off the ground by pushing down on the tail boom. Which means that anytime you’re working in the aft end, you need a spotter or something under the tail to keep it from doing a wheelie.

The pivot brackets were made from angle iron. A ¼-inch hole was drilled for the pivot (left) and then the mounting holes were drilled (right).

It turned out the antenna was the culprit. A simple swap to a known-good unit from the shop and the transponder was squawking at full strength. Go figure. For whatever reason, the dipole antenna I had been using wasn’t broadcasting anymore. The antenna they used for the test was a RAMI AV-74, shark-fin style antenna. I ended up buying it and took it home to install it.

Back at the hangar, I set about figuring out how and where to install the new antenna. Before climbing into the boom, I set up the usual stack of lumber and foam under the tail. While certainly stable enough, I realized it was a Mickey Mouse setup.

The pivot head was machined from a 2×1-1/4-inch-diameter piece of aluminum. The shank was first turned to 1 inch long by 0.875 inch diameter to fit the inside of the center tube. A light “skin kit” was made to true up the large end (left). It was then rounded over using a 5/8-inch-radius router bit (right). For more detail about rounding over using a router bit, see the Kitplanes® December 2022 issue.
A 5C indexer was used to hold the pivot head for milling the flats on each side (left). With the part index to 90°, the tip and side were touched off using an edge finder (right) to precisely locate the pivot hole.
Drilling the center hole (left) and test fitting the pivot head (right). The pivot head was epoxied into the post at final assembly.

What I needed was a dedicated tail stand. Something both sturdy and worthy of a professional-looking shop. In other words, a perfect project for the Home Shop Machinist!

The design I came up with is similar to the axle stands featured in the March 2019 issue of Kitplanes®. The main difference is that this is a tripod design. With four-legged stands, the wider the stance, the more they are affected by uneven floors.

The leg braces were tack-welded in position using a paper printout as a clocking guide (left). A feature of TIG welding is the ability to quickly and precisely concentrate the heat. Done correctly, there’s little risk of the paper pattern catching fire (right). In any event, always have a fire extinguisher nearby when welding!
The legs were carefully positioned and then tack-welded to the post (left). The tack welds were made on one lower corner of each miter. This allowed some tweaking into realignment before final welding (right).

A typical commercial tail stand has a shackle or yoke with a cross pin to attach it to a corresponding tie-down point on the tail. The Jabiru doesn’t have that feature, so I designed my stand with a pivoting 8×12-inch plywood table. Together with a generous foam pad to protect the paint, the table spreads the load over a wide area.

While the single post may look spindly, it easily handled my full weight (180 pounds) with nary a wobble. In use it will never see that much load. I figure during a typical ELT inspection, the most it will need to support is about 80 pounds and only slightly more if I have to reach the antenna connection.

The antenna install went well. I included the ground plane recommended by the shop, and when I went back for a retest, it passed with flying colors.

The pivot head, brackets and support table were lined up using a combination square (top). A self-centering VIX bit was used to drill the pilot holes for the wood screws (bottom).

Download the detailed drawing of the LSA tail stand. That’s it for now. Time to get back in the shop and make some chips!


  1. A beautiful piece of work that required a:
    Milling Machine
    Drill Press
    A $60 pipe stand from Amazon would do as well.


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