Jimmy Yawn's Page
Profile Information
- I Belong To:
- National Association of Rocketry, Tripoli Rocketry Association, Other
- About Me:
- Career counselor by trade, rocket geek by nature
- My Website:
- http://www.jamesyawn.net
- My Interests:
- Rocketry, of course, primarily KN/sucrose but all other kinds as well.
Photography, video, web design
Music - I play several instruments, none of them well.
Cooking. Eating. Playing with rocks.
- Things I'd Like To Do:
- Go more places, fly more rockets.
- People I'd Like To Meet:
- Pat Gordzelik, John Wickman, Terry McCreary, Jim Kennedy...
- I Can Provide Expertise On:
- Sugar rocketry, especially KN/sucrose
- Favorite Rockets:
- Saturn V
Proton
Or do you mean my rockets? I only have one, so it must be my favorite.
- Favorite Music:
- Classical, Ragtime, Early Jazz
- Favorite TV Shows:
- Nova. Not much else that is worth the time.
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The year so far:
January NEFAR launch, did a drag race between two Sugar Rush clones, each with a camcorder running. Video is at: http://www.nefar.net/gallery/2008-01/index.html
Tried it again in February, with Marc Slabbinck providing the KN/sorbitol BATES grain motor for one, me providing a KN/SU moonburner for the other. Marc's motor worked great, beautiful flight. I made a dumb mistake, substituting a hardware-store washer for the stainless nozzle support ring. (geez, it looks the same! Turns out is not the same. Nozzle exited the motor upon ignition, camera destroyed, rocket substantially damaged. I have not yet put this one on the web. But if you are up for a 90 meg download of raw, unedited video, I put the in-flight .mov file from the one that worked on the web at:
http://www.jamesyawn.net/NEFAR-2-9-08/SR2-in-flight.mov
Did a propellant-making workshop for Greg Peeble's student rocketry group at FIT a few weeks ago, which was a great success. I got to see their fancy new test stand, and we made a motor that will be tested on it sometime soon. The stand senses not just thrust, but rotation and angular forces. The motor is a moonburner so we can see some off-axis thrust. The sensors on this stand are supposed to be good enough to test anything from an A motor to a P motor. I took some pictures, I'll upload one when I find it again. This stand is a thing of beauty.
Students made propellant, then model-rocket motors, then larger motors for static tests. I feel that these events are sadly incomplete if there is no launch, so I offered to bring mini-saucers, which can be launched in a small area. Greg indicated that his students might want to build their own saucers, so I put my method on the web at: http://www.jamesyawn.net/CD-Saucer/index.html
Here's another page I've been working on that is not yet linked to my home page - it's on making the ramming-tool for forming clay nozzles in C motors:
http://www.jamesyawn.net/modelrocket/ramming-tool/index.html
Page is not quite finished - a lot of photos and text are repeated, but everything is there, at least once!
These little rammers work well for making packed-propellant motors too. Over Christmas break, I was in correspondence with a young man and his mom - he was working on a science fair project, wanted to use sugar propellant, and because of safety concerns did not want to cook it. So I worked up a procedure, ramming dry-mixed KNO3 and powdered sugar on top of a Bentonite nozzle using this former. They worked surprisingly well. Not as well as rcandy, but not bad, a longer burn time and about 2/3rds the total thrust. The kid won his local science fair, and placed well enough in the regional fair that he is going on to the state science fair. Validates my faith that rockets and kids can be a good thing, with proper parental supervision and support.
Right now I'm working to get it together for the April 12th NEFAR launch, where Ed Mallory of FSU will be bringing an electronics package for the "mini-shot" prelude to the Sugar Shot to Space. Parts of this package are being built by Hans Olaf Toft in Denmark and Craig Strudwicke in Australia. Ed will be getting it all together and fitting it into 3 inch tube to fit the aft section of the Sugar Rush. Calling it the "micro-shot," this will be to flight-test the electronics. I'll make the grain today or tomorrow.
Upcoming... I've managed to volunteer myself into a fun mess, helping 48 middle-school kids build the Snap Dragon kit in their Science class. We won't attempt to fly them, just build. Whew! Similar event for the local Boy Scout troops, where we will build Snap Dragons as part of the Space Exploration merit badge. We hope to do one of the required launches at my school later that day.
Wish me luck!
Jimmy
jyawn@sfcc.net
In the meantime, it's at...
http://www.nefar.net/gallery/2007-11/index.html
... and almost finished. I have a bunch of videos with no data on the flier, the motor, or the rocket name. I'm thinking I'll put them out there anyway and make a simulated milk carton with a picture and a caption: "Have you seen this rocket?" Get other folks to tell me the facts. Or make them up.
The Sugar Rush did not get quite as good a video this time as in October, which was the best so far. It spent much of it's flight time looking up at the clouds, and I don't need a rocket to do that.
I've acquired a high-definition version of the Aiptek camera, and plan to make a mount for it before the January launch. Video quality is much better. I hope it survives. I see that Panasonic is now making a similar camera that is marketed as "shock proof." I might help them test that contention at some point.
The biggest motor I've flown was the Big Sugar, 2005. It was a team effort with Steve Ghioto, who made the motor casing, Richard Creamer, who made the airframe, and me, who made the propellant. I got the fun job! It was a 2-grain PVC motor in 4-inch tubing, and tested into the "L" range.
Launches documented at:
http://www.jamesyawn.com/bigsugar/index.html
and
http://www.jamesyawn.com/bigsugar/NEFAR11-12-05/index.html
The first flight was better than the second.
There is talk of resurrecting this project. I'm going to vote for a metallic motor, perhaps even bite the bullet and buy one. That might be a good start toward a level 3 project.
For most flights I use commercially-made motor casings - Loki, Dr., Rocket, Rouse-Tech, DPS, plus a nice motor that Jonathan Carter custom-made for me, modifying the Loki design to my specs.
For avoiding trees, we rely primarily on luck. Luck is a great time-saver, cost-effective, and very reliable when it works. Unfortunately, there have been some quality control issues. For an example, see the recovery of Big Sugar #1 above. It was a dual deployment recovery - parachute at apogee, palm tree deployed at 30 feet. Descent time was 22 hours, 43 minutes and 16 seconds, requiring a tall ladder, a pole saw, and a large primate.
Makes me wonder - There are troops of feral monkeys at Silver Springs which is not far from the launch site. I hear they escaped while Tarzan movies were being filmed there in the 30's. I wonder if we could train them to bring back treed rockets? Put a banana in it?
Hi Clarence! Good to hear from you again! You know, I still have one of the flying 4x4s - maybe I'll send it up again someday. Funny that my largest flying fence post weighed less than the Sugar Rush does now. Recovery of that model was very reliable, if a bit scary and certainly not PC.
But it occurs to me that I might make an airframe from long plywood box so that it that looks like a 4x4 but has a normal recovery system. Could even paint it pressure-treated green. That would shake some heads, wouldn't it! Hmmm... I have some hardwood plywood out there...
Jimmy Yawn
How do you guys keep your rockets out of all those BIG trees? Thats something that we don't have. You might see some mequite, but nothing big.
Jimmy, whats the biggest sugar motor that you have launched in one of your rockets? Did you make the motor case or use someone else's such as AMW, Loki, Aerotech, ?
Harry Keyes
This might not help me much because I've made a zillion batches and know what to look for. But I would like to offer an "objective" method to others which is based upon measurable parameters. As you observe, it could help newbies make the stuff, but also might allow me make it more consistently. My burn rates vary a bit from batch to batch, and I'd like to be in full control.
An alternative on the "art" side of the equation would be to make a few batches of butterscotch or peanut brittle, so that one leans the cues from a less expensive, less hazardous, and tastier recipe.
Perhaps it wouldn't gain you all that much since you have the experience to have a feel for when it is getting close, but for someone less experienced.
Trouble is that the stuff is a heavy glop, and generally a thin layer on the top of the skillet. So a standard immersion-type thermometer would not likely work.
I have one of those infrared thermometers, which might serve, but it only looks at a spot, and the temperature varies from place to place on the pan surface... I keep stirring it to distribute the heat evenly, and to let the water vapor escape.
But I would be delighted to have a way to measure the temperature accurately, as I believe it would be a good indicator of cooking progress.
Any ideas?
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