Monday, February 23, 2009
Saturday, February 21, 2009
Today we tested a new catalyst pack for the blue ball. This is not the motor that we have been machining recently, its a new solid catalyst for the older stainless motor we flew last year. The test was almost perfect. We had no setup issues and everything just worked. The catalyst warmed up on the first burp and ran really well.
I have not yet reduced the data, but visually and audibly it was a better catalyst than anything we have run to date. There is a lot of literature and contradictory information on peroxide catalysts. I’ve personally watched others struggle to get a catalyst to work. A few posts ago I mentioned that I could not really talk about the catalyst design, I still can’t talk about the design, but I can offer some background. I’m always surprised by the number and scope of people that follow along on our journey. One of the people that stops in from time to time is Anthony Cesaroni of Cesaroni Technologies. He offered to help me with a known good catalyst recipe. Its a traditional peroxide catalyst, but Anthony provided me with an exact recipe and some tips on subtle mechanical issues I would have never figured out on my own. All I can say is it works exactly as advertised, I followed the recipe and it worked perfectly on the first firing.
I’ve posted two of the most Boeing you tube videos in history. You see absolutely nothing, which is as it should be for a properly working peroxide catalyst.
I’ll have some comments on the recorded data in the next few days.I know I got data and I have not had time to look at in in detail.
Thursday, February 19, 2009
How it all goes together. The bare chamber
1/2 The split throat outer on the chamber
Both halves of the split throat outer on the chamber.
End of the motor assembled (Rear outer not installed, its really just a sleeve.)
Detail showing the fit between the chamber outer and inner.
Detail of the end where passages end and go into the chamber above the cat pack
All welded up
Lastly doing the water flow showing no leaks on the bottom and all cooling channels are open and free.
I still have to work on the top end closure and top side catalyst retainer, but its really close and I’m happy with the results.
Tuesday, February 17, 2009
For weeks the suspense has been building…. I’m making the last cuts on the aluminum chamber.
The Second Passage (Too nervous watching to catch first pass)
A third of the way around….the black line is a Sharpie ink mark not a cut.
It should be done by morning. I’m going to bed and my Son is Babysitting the mill.
I live about a mile inland from the beach in California, we get a lot of salt air, everything rusts. You can see rust on the mill even though that spray you see going everywhere has soluble oil in it. This setup was about two inches too long to put the normal spray guards on the mill so I’m trying to keep the lubricant in the mill with some Plexiglas pieces. I’m getting coolant on EVERY thing.
Sunday, February 15, 2009
The Cat screens and Cat assembly is complete. The modified Motor for the Blue ball is 100% ready to test. We hope to test next weekend. Depending on how the 2009 LLC rules turn out we could be doing flight test in as little as two or as many as 10 weeks. If there is some rule advantage to flying the 90 second vehicle soon we are basically ready. If there is no advantage to flying that before the 180 second vehicle we are a 4 weeks away from doing a full up static test of the 180 second vehicle and probably 6 to 10 from flying it. After I finished the motor for the blue ball I spent an hour aligning the Rotary table and rotary Table Tail stock. This was in preparation for cutting the slots in the aluminum regen motor for the 180 vehicle. After watching armadillos efforts on the 180 second vehicle with the various burn through issues or longevity with insufficient performance issues I’m somewhat convinced that one needs to run a regen motor to get to 180 seconds. John or someone else could easily prove me wrong, but thats my current opinion. Thanks again to armadillo for being so public about their process publishing both good results and bad.
We have to run some materials out to the test site, so Monday (A holiday for Netburner.) will be lost to the drive. We will be going out again at the end of the week to test.
Wednesday, February 11, 2009
I’m building a screen based catalyst for the blue ball. Unfortunately I can’t talk much about the catalyst construction, I have a NDA with a third party that covers parts of the design I have parts that are from public sources and parts are my own creation alas its hard to tell what part I’m free to discuss here so I won’t really give any details. One of the steps in the process involves cutting about 100 disks from some screen material. I want these to be fairly tight in the bore of the cat holder, so I measured precisely , twice and got the disks all cut at thunderbird water-jet. After all the subsequent processing the disks were all about 0.05” too big. They bowed big time when forced into the bore. So I spent my evening building a fixture for the CNC mill that precisely places the slightly too big disk, clamps it around the edges and then mills off 0.05” from the diameter. In the final process I did the disks 6 at a time with a clamp, rotate 90 degrees and re-clamp step in the middle. It took me about 2.5 hours AFTER I built the fixture. Arghhhhh. In any case I’m going to go to bed before 11:30!!! What a treat. Remember boys and girls sleep is a no credit elective!
Monday, February 09, 2009
I finished the shells for the regen motor. So I have the inner core and the outer shells almost all done. All I have left to do is cut the cooling channels in the inner core. I only made one minor error in the set of pieces and I fixed that with some valve lapping compound and 3 hours of elbow grease. Based on what I can see and measure the worst case gap between the shell and inner is 0.005” Most places its tighter than that.
If all goes well I’ll start cutting the cooling channels Monday night. And I’ll have it ready to test by Friday.
Whine the weekend was spent machining one can never seem to avoid writing software ;-)
I wrote a lot of software this weekend. I have several good programs to convert CAD drawings into instructions for the milling machine, I have not found a good one for the Lathe. I tried a demo of an expensive lathe cam package and it crashed on about 50% of my drawings. So if the demo crashes how good is the production S/W going to be? So I wrote some code that takes the line geometery for the part to be made and makes lathe G code. It works for both inside and outside roughing and finishing. Some day I’ll even put a UI on it so you can change things like tolerances and mode without recompiling. CAM software for the lathe is something I’ve been meaning to do or research and buy for a long time, I just got tired of measuring a bunch of points and shapes on the cad drawing, moving them to excel then doing a bunch of geometry calcs in excel, and finally hand translating them to g code in a text editor. My one macining error looks like it was a transposition of two digits on the coordinate for the center of an arc. I’ll take pictures of the parts and maybe even a short video showing how it all goes together.
Monday, February 02, 2009
One very long day and two evenings and I’ve turned a 65 lb chunk of aluminum into a 4.5 lb chunk of aluminum shaped like a rocket motor. My turnings recycling bin and spare trash can both are full the overflow is on the floor….
The result looks nice….
Now to make the outer shells and cut the cooling channels.