How To Make a Windsock Mast

Ralph Sickinger

SO... There you are; all those trips up the training hill have paid off, and your instructor has finally decided that you're ready for "the big one"... your first mountain flight! You've got your glider, your harness, your helmet, and your parachute. You probably have a radio too, (You've taken the ham radio exam, right?), and you've spent plenty of time visualizing your flight; from pre-flight, through launch, flying out to the LZ, making your approach, right on down to the perfect flare and a no-step landing. Have you forgotten anything?

When you fly the training hill, you know which direction to land in: probably the same direction you took off in. Or, there were a bunch of streamers out in the field, placed there by your instructor; but out in the mountains, you're responsible for your own flying. The wind in the LZ can be very different from the wind that you launched into, and you're going to have to figure out which way it's blowing (and how hard), all by yourself. The advanced pilots can give you all sorts of advice on determining wind direction from the air: looking for smoke or dust blowing, ripples on water, circling and establishing drift direction... These are all good techniques to keep in the back of your mind, but nothing beats a good old windsock standing in the middle of the LZ.

Recognizing that your observer is an advanced-rated pilot, who normally flies cross country (when he isn't generously sacrificing his flying time to throw you off the mountain), if you want to have a windsock in the landing field, you're going to have to put it there yourself. USHGA has a very nice sock available on their web site, which I highly recommend, but you'll have to make your own mast for it. Here is a design for a windsock mast which is inexpensive, fairly simple to construct, very compact and transportable, and quick and easy to set up and break down.

First, a little bit of background on the design: My windsock mast has gone through several iterations since I first built the original in 1999. For my original design goals, I wanted a mast that was quick and easy to set up; but it had to fit in the trunk of my car (which dictated a maximum length of 4' for any segment). It had to be at least 7' long (the sock itself is almost 5', and the mast has to be tall enough for the sock to clear tall grass), and sturdy enough to be free-standing (guy wires take too long to set up, especially if they get tangled while they're in the car). My original inspiration was a pool cue; I built my mast out of wooden dowels, and it took me weeks to construct the screw mechanism to join the two halves. It was a sturdy design, but it took too long to thread and un-thread the pieces, and then one day, somebody hit the windsock while landing. As I gazed at the wreckage of my masterpiece, I realized two things: first, if you put a windsock in the LZ, at some point it WILL get hit; and second, because of this, the design needs to be impact-tolerant. Ideally, the mast will give when it gets hit, so it doesn't upset or damage the glider that hits it. You also want the pieces to be easily replaceable, so that you can repair the damage quickly and easily. My design is for a two-piece mast made out of inexpensive PVC pipe, with a wooden dowel core; the two halves are joined with 3/4" hardwood dowel which should serve as a break-away if the mast gets hit. It's anchored by a 17" long 3/8" steel rod, which will hold the mast up even in soft, damp, Spring earth. All in all, it's a pretty simple design, so this shouldn't take too long to build. Ready to get started?

Let's go shopping...

In addition to the USHGA Windsock ($44.95), you'll need the following parts from your local hardware store (Lowes or Home Depot):

(1) 10' x 1" (o.d.) PVC pipe
(3) 4' x 3/4" round hardwood dowel
(1) 3' x 5/16" round plated steel rod
(1) package [10 pcs] #10 x ½" pan head
sheet metal screws
(1) 5/16-18 x 1" hex cap screw (bolt)
(2) 5/16" flat washers

Total cost of the parts: $12.50

The PVC pipe [actually, it's 3/4" electrical conduit] can be found in the electrical section of the hardware store. You'll want to find one that is as straight as possible - a lot of them have pretty severe bends in them, and you won't be able to straighten them. If you can't find one that's straight, try to find one with the bend in the middle, so that you can at least get two straight sections out of the ends. You'll know you have the right size if the 3/4" wooden dowel just barely fits inside the pipe.


In addition to the above, you'll need a 3/8" auger bit and some way to grind metal. If you don't have an actual bench grinder, you can use one of those combo sanding/cutting/grinding disks, the kind that go in a hand drill.

Cutting things down to size...

In step one we're going to cut the conduit, the dowels, and steel rod. We'll use a hacksaw to cut the steel rod into two parts; this will give us two spikes, so we'll have a spare in case one gets bent. (It happens.) I like to cut 16"-17" from each end, leaving a 2"-3" middle section as scrap. You could just cut the rod in the middle, but you'll end up with 18" spikes, and that's that much more that you have to drive into the ground. In my opinion, that's longer than you need, and you'll appreciate the shorter spikes in August, when the ground is baked and every inch makes a difference! Next, we'll cut two pieces from the PVC pipe; the bottom section should be 46" long, and what will eventually be the top section should be 44" long. One end of the conduit is flared, and we'll cut that off and discard it. This will leave us with a leftover piece approximately 28" long; we'll save this for use as an optional center extension. Next, we'll cut 4 pieces from the wooden dowels: 36" long, 28" long, one the same length as the center extension, and one piece about 6" long. Figure 2 shows all of our assorted pieces-parts, labeled and ready to be worked.

The shape of things to come...

Now comes the fun part. The steel rods need to be ground down into spikes. The best way to do this is with a bench grinder and a hand drill. I put the end of the rod in the drill chuck, and hold the other end against the side of the grinding wheel. The drill keeps the rod turning as it gets ground down, resulting in a nice round point. If you're not using a bench grinder, you can use the grinding disk, or a even a file, and simply file the rods down to a square or triangular point. It's up to you decide how sharp a point to put on your spikes, and how long you want to taper them. It takes more time to grind a longer taper, but it will go into the ground much easier.

Now that we're done with both spikes, we can move onto the base core. This is the 28" wooden dowel, and we want to bore a 3/8" diameter hole down it's axis, as shown in Figure 3. We want to make this hole as deep as possible, and the 3/8" auger bit will bore a hole 6 ½" deep, which will do. It's important to keep this hole as straight and as centered as possible.
Next, we'll take the top core [the 6" dowel piece], and drill a 1" deep hole using a 1/4" drill bit. We actually want the hole to be just a little larger than 1/4", but not as large as 5/16", so we'll "wiggle" the drill bit a little to expand the hole. We'll take the hex bolt, and use a wrench to carefully turn the bolt, so that it screws itself into the wooden dowel, creating it's own threads as it goes. Be patient when you do this - it's easy to cross-thread the bolt and strip the threads that you're creating. Also, keep in mind that you only need to thread the hole about ½" deep - the other half of the 1" bolt is going to extend beyond the end of the mast to hold the windsock itself.

At this point, we're almost done; if you want to paint your mast though, now is the time to do it, before we go into final assembly. I recommend sanding the outside of the PVC pipe, for two reasons. One, the paint will adhere better; and two, if you don't remove the lettering on the outside of the pipe, it will show through the paint, even through 3 coats! (Don't ask me how I know this.)

Putting it all together...

Now we need to mount the two fixed core pieces into the main mast sections. For the bottom piece, insert the core until about a 1/4" is left protruding from the end of the PVC tubing. Using a 3/32" drill bit, drill three holes all the way through the PVC and the wooden dowel (see Figure 4). Make sure that the first hole is at least 8" from the end of the pipe - you don't want to go through the drilled core of the dowel! Insert a pan head screw into each end of each hole (total: 6 screws), to anchor the dowel within the PVC (see Figure 5).
Now do the same with the 6" dowel piece and the top mast tube, which only needs one hole drilled through it and 2 anchor screws. And we're done! Figure 6 shows all of the completed parts, laid out side-by-side. I added some pieces of bicycle inner tube near the bottom, to hold the spikes when they're not in use. You can also use rubber bands for this purpose, or just call me - I have plenty of inner tube left!

In the field...

To set up your windsock, drop the rope loop over the top of the mast; place one of the washers on the bolt, and insert the bolt through the grommeted hole in windsock's plastic frame. Place the other washer on the bolt, and then screw the bolt into top of the windsock mast, as shown in Figure 7.

Be careful not to tighten the bolt - you want the sock to be able to rotate freely!

Insert one of the spikes in the hole in the base, and drive it into the ground. If the spike hasn't gone into the ground far enough, you can actually use the base to pound it in further. (This is why the core is anchored to the PVC with screws, instead of just being glued in.) Drop the center core [the 36" dowel piece] into the base, and then put the top part of mast over the core.
(See Figure 8.) And that's it!

With our completed windsock, we are now ready to go fly the mountains.