That's a nice assortment...
How much is PVC? I would like to build a couple to work on some MPR.
Lets say you have a rocket that's 30" in length, how far apart should the supports be? Would 20" work??
PVC is pretty cheap, especially in 1/2" and 3/4". Starts getting pricier in larger sizes. Attached is an article I wrote a few years ago for our section newsletter (the photos are in previous posts). The only requirement on size is that the Cg of the section you put on the stand has to be between the uprights. That sometimes gets to be an issue if your fins are long, as they hang off the end.
Easy Weekend Projects with PVC
Polyvinyl chloride is a biologically and chemically resistant plastic commonly used for drainage and ventage systems in household plumbing, where cost and corrosion limit the use of metal. PVC products are abundant, relatively inexpensive, and lend themselves readily to projects useful in sport rocketry. The term "schedule" refers to the thickness of the pipe wall. Schedule 40 is the most commonly available, and a good assortment of pieces can be found at any home improvement center (Lowes, Menards, Home Depot, etc.). The outside diameter of the pipe, and the inside diameter of the fittings, are the critical dimensions. The inner diameter of the pipe is not particularly consistent, and may even vary down the length of the same piece of tubing. One limiting factor is that not all the pieces may be available locally in all sizes. For example, while you can get Elbows, Tees and Crosses in almost any size, none of my local building super stores carries corner pieces at all (called a "side out", with 3 sides at 90° angles to each other, like the XYZ origin in Cartesian coordinates.) This would make a great tripod hub, but evidently has no practical application in local do-it-yourself plumbing. A quick google search will find internet suppliers with every piece you can imagine. Plan ahead so as not to be caught short.
Another limiting factor is the hazardous odor emitted from the brush-on primer and solvent used to physically connect the pieces. Use only in well-ventilated areas. The typical rocketeer is already safety conscious as well as familiar with chemical precautions from the epoxies and paint we commonly use in rocket construction. The glue is two part, but you don't have to measure or mix it. The parts come in screw-top metal cans with a brush in the lid, you paint the primer on both surfaces, then paint the solvent on both sides, then press them together and hold for a few seconds. You don't have a lot of time before it sets. The good news is you can get a lot done in one build session, as things go together quickly. The bad news is you pretty much have only one chance to change your mind, so take care to get things lined up and straight the first time.
The pipe comes in 10 foot lengths, and can easily be cut with any saw. I use a radial arm saw with a jig, as I prefer to cut a bunch of pieces at once. Having them all the same length and with square ends also helps avoid alignment problems when venturing into the third dimension.
One of the most common project made from PVC is the field stand. Field stands are ubiquitous - a wide variety of them can be seen at most every launch gathering. They are wonderful for the assembly of components during build, storing your rockets between launches, transporting your rockets in the car, and holding them during pre-flight setup in the field. Many sizes, many styles, but all seem to share the "cross" in the center of each end. I made four sets of these using 3/4" PVC pipe, a little larger than required for my then biggest rocket, the 4" Rogue Comet. When my fleet expanded to 5.5" tubes, these stands still worked fine. When I added 7.5" and larger rocket bodies, I made two more slightly larger sets using 1.25" PVC, which have no difficulty holding 10.0" tubes and the corresponding gain in weight. Pre-slit pipe insulation fits perfectly over the 3/4" PVC, making nice cushions to protect your rocket's paint. I could not find suitable insulation to make the pads for the bigger PVC, so I segmented and cored out the insides of a styrofoam pool float toy, which works just fine.
Another common sight at launches is the PVC launch pad. They can be made as simple as a straight tripod (with three or four legs), and/or with adjustments for windage and elevation. Strong and light, removable legs, easy to rinse off the exhaust residue with no corrosion, and low financial investment are all big pluses for the PVC pad. I have two, made from 1.5" PVC, and I doubt I had over $10 tied up in the project initially. (Originally, my legs just pressed in the 45° elbow joints at each corner of the cross hub. I later copied Scott's pad design with screw in leg fittings, which made field disassembly easier but about doubled the cost.) Mine are not adjustable in launch angle, but the legs can be shimmed to tip the rod as necessary when required. My pads have 1/4" and 1/2" rods, the latter of which has launched J impulse motors with no difficulty.
A variation of the field stand is another great PVC project - the transport rack - when you have to bring a bunch of rockets with you to the launch site without breaking anything. While surfing through the excellent photo gallery archives of
www.CoolRocketry.com (thanks, Mark!), I came across this most excellent transport device (see Photo 7). The rocketeer who built this can haul a whopping 32 large rockets with no worry about them getting scratched on the way. Totally awesome. Never too proud to steal a good idea, I measured the cargo bay of my Trailblazer and downscaled one to fit. It also holds a bunch of rockets up off the floor while being stored in my basement, which led to the final variation of the field stand... the storage rack. Very similar to the transport rack, except there is no way this thing will fit in anybody's car. As my fleet has grown in both numbers and size, storage space becomes more important. I ended up running out of floor space while storing rockets horizontally on field stands, knocked them over like bowling pins while storing them vertically, and hanging them from the ceiling is not always an option. Out of necessity was born the PVC storage rack. Taking up about 3' x 6' of floor space (plus some overhang when necessary), it can stack 15 rockets with full 10" diameter bodies - more if smaller bodied and double-stacked. Photo 11 shows it almost completed, just needing the 45° elbows on the ends of individual shelf rods (to keep rockets from rolling off onto the floor), and it's feet put on (to raise it high enough to utilize the bottom rack). Also, I am searching for a suitable product to pad the shelf rods, leaning now towards foam and socks.
Of note, PVC is also used medically to describe Premature Ventricular Contraction, a relatively common event where one's heartbeat is initiated by the heart ventricles rather than by impulse-generating tissue in the right atrium. A PVC may be perceived as a "skipped beat". In a normal heartbeat, the ventricles contract after the atria, maximizing the amount of blood to the body and to the lungs. In a PVC, the ventricles contract first and circulation is inefficient. PVC frequently occurs spontaneously with no cause, and single beat PVC events do not usually pose a danger in healthy individuals.