Weekend Rocket Activities

This past weekend was full of rocketry. First off I was able to see the fifth Sugar Shot motor test over at the FAR site. Look for more details and photos on the Sugar Shot site as the post test information is reviewed and analyized. My photos of the firing can be seen here.

It was also one of the busiest Reaction Research Society launches over at the RRS site that I've been to in a while. In talking with some of the other members I found out that their online gallery area has had a number of additional photos added recently. I haven't checked it out yet, but I suspect there are some great photos there. You'll have to register to view the galleries, but that's simple enough to do. Some of the highlights of the day were seven successful Zn/S rockets flown by a group of middle school kids. A static test of a film cooled 4000lb thrust engine. USC flew a large two-stage rocket. A Zn/S rocket with two nozzles at the top. I also had a good test of a 600lb thrust motor that I will be posting details of in the weeks to come. All of my photos of the RRS activites can be seen here.

Blog maintenence/missing photos

I recently activated my Picasa web album which is were the images uploaded to Blogger are stored. In an attempt to clean up some duplicate images in that album I inadvertently broke a bunch of photo links to some in my earlier posts. I think I've got them all fixed now.

Photos from November

Last November my friend James and I participated in a propellant class at the FAR site. James took some great pictures of the days events. The pictures above are of my KNO3/sugar motor and of my AP/AL/HTPB motor. The photo of the composite test was taken during the day but was "stopped down" in an effort to reveal the shock diamonds. Video of both of these firings can be seen here. More of James' photos of the days events are online here.

Harvesting Aluminum Flake From Paint?

Richard Nakka recently added a page to his site about harvesting aluminum flake from paint. Actually, there are several new additions to the igniter page that I found intersting. I'll defer to Richard's page about the usefulness of flake aluminum as a thermic agent for igniters and the harvesting details.

I haven't had much time to devote to rocketry lately, but this technique seemed so simple and the cost was so minimal that I decided to give it a try. One thing that I noticed was that the lip on the paint can made it difficult to get all of the slurry out of the can and it was difficult to determine how deeply to insert the siphon. Too deep and you just sipon out the actual aluminum. I ended up transferring the slurry to a baby food jar for the 2nd acetone wash. Not only was it easier to get the slurry out of that container, but being clear glass I was easily able to see when the aluminum had settled. It was also easier to see the placement of the turkey baster used to siphon out the acetone ensuring that a minimal amount of aluminum was siphoned out. I ended up with a yield of 34 grams from a half pint of Rustoleum 7715 aluminum paint which is easily enough for 50-75 igniters.

Amateur Icelandic Rocketry (AIR)

Magnus Gudnason and Smari Freyr Smarason of AIR recently static tested the two motors intended for a two stage project to be launced later this year. Some preliminary test results can be seen on their forum. I think that this could be one of the best "sugar" powered launches to date, definitely one to keep an eye on.

Old Launch Photos and Stuff

Going through some old photos and rocket related things recently, I came across some photos from 2002. At that time two of the largest motors that I had were designed around two inch diameter "washing machine standpipe" that I found at Home Depot. I decided to try these pipes at the time because they seemed to be very good quality, good/consistent weld, and dimensionally consistent. They also have a thin (0.035") wall thickness which makes for a very lightweight casing. I designed two motors that utilized this casing material. Both motors used identical casings, bulkheads, and closures, but one was designed to use a single unrestricted grain and the other a single restricted grain. The differences in the nozzles are shown in the drawing above. I was concerned about the low initial thrust of the motor that used the single restricted grain and tried to reduce the weight of the nozzle for that motor as much as possible. In the end both motors ended up weighing nearly the same (1.75 lbs). I static tested the unrestricted motor and the numbers correlated closely to the design. Ultimately both motors flew numerous times at the RRS. They were simple to prepare on site (due in part to the fact that each needed only a single grain and that the motor was used as the casting mould). The motors proved to be durable, consistent, and fun to fly.

In the first photo you can see the casing with its nice shiny zinc coating. It is not that shiny from Home Depot, but the finish didn't take much time. Unfortunately the zinc blistered after the initial firing, so the coating was removed with a quick dip in muriatic acid. The 5th photo shows Peter and I taking the rocket out to the launch tower. The 6th photo shows (from left to right) Greg Coleman, myself, Kevin Koch, and Alan Hoyt lifting the launch tower into position. The 7th photo is Kevin, myself, and Alan. The orange and black aeroshell flew a total of five times at the RRS on three different motors. I made it from three inch diameter heavy walled cardboard tube that Kevin found in a dumpster. The fins were cut from quarter inch plywood and were epoxied on to the tube and reinforced with a layer of heavy fiberglass. The nose cone was turned from a block of pine. Eventually, it became too small for the new motors that I was making and was retired. It was always difficult to adjust the tower for it correctly since it had three fins and the tower at the RRS is built for a four fin rocket.

Photos 6-10 were all taken by Tony Richards.

Camera Rocket Recovery Photos

I recently ran across a couple of photos that I hadn't seen before (here and here) of the rocket I launched in April 2007. I found the photos on the Mojave Desert Advanced Rocket Society website located here. I recognize a couple of folks in the web site's photo section from motor classes that I recently participated in including the MDARS president Kevin Metzler. The photos of my rocket were taken by Dave Allday.