Some time back I had the opportunity to pick up a used Walston Retrieval transmitter and receiver. Everything works, but the transmitter is huge compared to my original transmitter.
My original transmitter was purchased for use with the receiver owned by one of my fellow Idaho rocketeers. Unfortunately that transmitter is not on a frequency received by my receiver, so it is of no use to me here.
The new transmitter, in addition to being huge, has the non-rechargeable batteries potted in epoxy and is controlled via a normally-open, magnetic reed switch. This means that a magnet must be attached to the transmitter at all times in order to keep it turned off. All this means that it will be very difficult to replace the batteries when they run out and I have no idea how much time is left on them since the equipment was purchased used. Additionally I have found the magnet detached on more than one occasion, burning more time off the batteries needlessly.
I attempted to contact Walston to purchase one of his smaller transmitters, like my original, at a frequency I could use with this receiver. Unfortunately he proved impossible to contact and rumor has it that his health is failing, so I was forced to search for another vendor that could supply me with a transmitter which would work with my
receiver.
After discussing the issue on one of the rocketry forums I contacted L.L. Electronics and purchased one of their transmitters. They were a pleasure to do business with with friendly, informative staff.
My new transmitter arrived yesterday and, as promised, my Walston receiver started chirping away when I turned it and the transmitter on. The new transmitter is more compact than my original Walston, thanks to my having selected the "loaded antenna" option. I know I've traded some range in exchange for compactness, but I suspect I was sacrificing range with the Walston because I was having to loop the antenna around to get it to fit in my nose cones. It isn't as if I'm one of the guys launching to +20k', so I think I'll be fine. If I should ever decide I want the non-loaded antenna for a bigger rocket they are available for a modest price. I just wish I'd thought of that when I ordered my transmitter so I could save on the shipping!
Digging into my rocketry gear I located my AltimeterTwo still installed in Flying Colors from the last time that I flew. I plugged it into a USB port and left it charging overnight. The next day found that it was still indicating it was charging, which I would not have expected. Still, after that long on the charger it should show me something if I turned it on, so I unplugged it and did just that only to discover that it wouldn't turn on. I contacted Jolly Logic support and they advised me that the Lithium batteries used in many devices, such as your cell phone, including the ones in their altimeters must be kept charged or they will discharge to a point that they can't be recovered. The only option was to have the battery replace, a service they provide. I shipped my altimeter off to California where they did a quick battery change and promptly shipped it back to me. I received it yesterday and was able to immediately turn it on and see the data from my last flight was still available. It is now fully charged and I have a calendar reminder to recharge it once-a-month.
As promised, Amazon delivered my new scale and calibration weight this morning. I just got off work and decided to take another shot at applying Icing. I intended to mix a 5g batch, but wisely started by measuring the hardener, since this is a tiny amount compared to the putty. As careful as I was being, I still ended up with a 0.2g dollop of hardener, so my batch immediately became a 10g batch. The smaller batch was much easier to work with and I got most of it applied to the rocket and spread out thin, so I'll have much less sanding to do!
As anticipated, my Icing order arrived yesterday. When I got off work I mixed up the smallest batch I could measure (49g paste, 1g hardner) and applied it to my rocket. Unfortunately the working time for this stuff is very short and it quickly started setting up on me, to the point that I got less than half of it applied to the rocket. What I did get applied ended up being thicker than I wanted in many places and got botched in one area, as I tried working it too long. The net result is I'm going to end up sanding off most of what I got applied! I spent a fair bit of time sanding yesterday, until my hands hurt too much for me to continue. More sanding this afternoon, time permitting.
Obviously I need to mix smaller batches. Since my current scale only measures in increments of grams I really have no choice but to purchase a new scale. I've had such a scale in my Amazon wishlist for a long time, as I'd already determined I needed one for weighing black powder ejection charges. I placed an order this morning for a scale, but not the one I had saved. The one I ordered has twice the range of the one I had saved, 200g, while having the same resolution, .01g. I should be able to mix very small batches now, if I need to.
To help ensure accuracy of the scale I also purchased a 200g calibration weight. I just hope the weight is accurate. While the vast majority of reviews on Amazon praise the weight, you will always find those that complain. If the complaints are accurate there are times these weights aren't worth using for fish sinkers! I'll just have to use my best judgement when it all arrives.
Earlier this week I went out in the garage to mix up some of the Icing filler, that I purchased while living in Idaho, and work on finishing my tubes. I don't know if it was just time or the high heat our goods went through while being shipped from Idaho to Texas but both the putty and activator were destroyed. Since I only got a single use out of that supply it was an expensive use. Tried to find a supplier locally, but nobody seemed to know what I was talking about, so I ended up going on-line and ordering through Amazon. It looks like it should be here tomorrow.
I really can't believe it has been this long since I last posted. After a brief spurt of activity my rocket building went back into idle mode. Now I've set myself serious goals in order to give me a reason to get busy. I am planning on attending XPRS 2017 and BALLS 2017. To do so means I need to build rockets and get at least one ready that I can fly on a "K" or "L" motor, since the smallest commercial motor allowed at BALLS is a "K".
Last week I finally epoxied the fin can and motor retainer to my scratch built rocket. I applied a band of five-minute epoxy at the aft end of where I expected the fin can to mount and then slid the fin can up, twisting as I went to help distribute the epoxy in the join. I had to wipe off some excess epoxy from the front of the fin can, but it wasn't a major issue. I left that to set for 24 hours before using JB Weld to mount the retainer. I followed a very similar process for the application of the epoxy and sliding on the retainer. Clean up of excess weld was a bit more difficult. I ended up resorting to paint thinner in order to get the excess removed.
Next step is to mix up some of the filler to help smooth out unevenness in the epoxy on the airframe tubes and then sand, sand, sand.
I received 8 aluminum bulk plates from a rocketry friend back in Idaho. These were cut on a water jet, which left the edges rather rough. A coworker offered to make me a arbor to mount the plates on so I could easily sand/file the plates to size and keep them round. Works like gang busters! Thanks to both Dave and Michael for helping me move my rocket forward.
Two of the bulk plates. The one on the left is the unfinished edge produced by the water jet. The one on the right has been sanded using the arbor.
The mounting surface of the arbor.
Another shot of the mounting surface of the arbor.
For the first time in over two years I put some work into one of my rockets. Things are going to be slow as my budget is limited, but I'm looking to get going again.
I received a Slimline Qwik-Lok motor retainer for my 54mm project I started several years ago. Since the tubes are LOC Precision tubes with a layer of glass on them I had to sand down some of the glass in order to get the retainer to go on. Next I have to work out exactly how I want to proceed in epoxying on the fin can and retainer.
I puzzled over how to name this post for quite some time. I'll tell the tale and then you'll see why.
We had a late start on our day at the range due to Sam having a school event in the morning, so it was afternoon before we got to the launch site.
As I unloaded the car I realized that I hadn't charged my AltimeterTwo since I last flew it more than a year ago. That meant it was almost certainly "flat" inside my rocket. I cracked open the payload bay and sure enough, there was no charge at all. I fortunately had come prepared to charge USB powered devices and got the altimeter plugged in and charging while I worked on the rest of the rocket.
I began loading up the 232H123-14A motor I purchased last and pulled out my Android with OpenRocket on it to determine what delay I should use, only to discover that I hadn't gotten the motors loaded into the rocket configuration file and therefor couldn't run a simulation. I was left to guess as to expected altitude and what delay I needed to use. Based on past experience I guessed I would fly 2000'-2500' and opted to not make any adjustment to the delay grain, as they have always been just right, or on the short side for Flying Colors, and loaded the motor.
I then waited around while the altimeter was charging. I set up my cameras at the pad and test recorded a flight of another Vulcanite. With the number of rockets headed to the pads slowing to a trickle I decided it was time to get Flying Colors assembled and flown. Final assembly was quickly completed and soon Flying Colors was on its way, atop a column of black smoke and sparks. I lost sight of it for a short time, but spotted the smoke trail as it was descending and saw the recovery system deploy. Since it had headed up wind it landed reasonably close to the launch site. Samantha and I quickly reached it. Everything looked fine at first, but then Sam spotted the "zipper." Thanks to the fiberglass reinforcement I did during the build it isn't bad and should be reparable, but it could keep me from flying next month. I need a number of supplies in order to do the repair right. It has been suggested that I cut off the damaged portion, but if I do that the payload bay coupler is going to hit the recovery system mount point inside the airframe.
Of course this damage could have been avoided if I had made appropriate decisions. When I discovered I couldn't simulate the flight I should have aborted the launch. If I had simulated the flight I would have seen that I needed to adjust the delay grain by 3 seconds. Since I didn't make this adjustment Flying Colors descended some 400' before ejecting the recovery system which allowed it to build up a head of steam which resulted in the "zipper" when the recovery system did deploy. I'm lucky to have gotten off with as little damage as I did and will definitely take this lesson to heart. Don't guess, simulate. If you can't simulate, don't fly.
So, back to naming this post. With the damage that occurred to the rocket during the flight I considered several names for the post, along the lines of "Rocket vonZipper!", but decided most folks wouldn't get the reference. Also I'm not happy about the outcome of the flight, so I'm not really in the mood to joke about it.
The last post was actually posted long after the event, as I forgot to take care of it right away. Lots of screwy stuff was going on at work which culminated in permanent layoff in December. I'm hoping to get back to flying soon and discovered the launch was missing from the blog.
When we do get back to flying it will be at a new location. I landed a new job in Texas and expect to be flying with the AARG (Austin Area Rocketry Group).
It was another fine day for flying, with clear skies and mild temperatures. I sent FLying Colors flying on it's 10th voyage, powered by a CTI 538I303-16A, to an altitude of 6374'. Everyone lost track of it, so I was forced to rely entirely on my Walston Tracker to locate the rocket. This was the first time I had to rely entirely on the tracker. It led me on a bit of a circuitous route since my rocket had landed beyond a ridge, but I did locate it.
When I returned from recovering Flying Colors we loaded a motor in my wife's Wildman Wildchild that she has named Wild Flamingo on a CTI 108G68-13A motor. My AltimeterOne altimeter was attached to the shock cord using the vendors included wire clip. When we recovered the rocket there was no sign of my altimeter and it appears to be lost for good. It was a first generation AltimeterOne which differed in a couple ways from the current product, so I'm not happy about having lost it.
After getting several days of rain last week, the BLM cleared the launch site for use. The weather forecast looked good for Saturday, so yesterday was our first launch of the fall season.
My daughter got to launch her new Dark Star Mini on a Cesaroni 84-G88-1A to 1754'. The expected altitude was 2287', but the wind was blowing pretty good when she flew and that likely had a significant effect.
After recovering the DS Mini I flew Flying Colors on its ninth flight. I loaded an 819J354-16A, the highest impulse motor I expect to be able to load in this rocket and sent it to 8091' AGL, a new personal best. In addition to my AltimeterOne, I had my new AltimeterTwo mounted and was looking forward to getting data from it, but due to some delays after I armed it, it apparently timed out and turned itself off before launch. This flight was projected to be supersonic and I really wanted to see if I made it. I'll have to wait for spring now to see if I'm actually exceeding Mach 1 as predicted and to test if I exceed the single-axis G limit of the AltimeterTwo, as none of my remaining reloads for this season will do either of those jobs. In addition to my altimeters I was once again flying one of Vern's prototype "Kate" nose cones. She performed up to her usual high standards and did an excellent job reporting the events of my flight. Thanks to the landing coordinates she provided I was able to once again walk right to Flying Colors, which was recovered in excellent condition.
Unfortunately, due to other commitments, we were unable to stay for the entire day. The winds were calming as we left and it looked like a number of big rockets and motors were being prepped for flight.
Issue #293 of Apogee Components' Peak of Flight newsletter was published today with the feature article I wrote about mounting the AltimeterTwo for use in high-G rockets. This is the first time I ever wrote an article for anything, so I'm quite pleased. I should have included thanks in the article to my friend, Jamie, who provided substantial feedback when I asked her to review the article for me. I should also have thanked John at Jolly Logic for confirming details about the construction of the AltimeterTwo which were necessary to correctly design the mount. Now I just have to wait a couple more months before I can fly the altimeter in Flying Colors. Presently Tripoli Idaho is in its summer launch hiatus due to the annual fire risk here. Come on Autumn!
Supplemental and higher resolution photos of the build are available in this photo album:
Yesterday was our final launch opportunity of the spring season. We had a very good turn out with many launches. I shot quite a lot of video, capturing 15 launches in 13 segments. There were many more launches than that, but I wasn't always in position to take video. I was there to fly my own rocket after all.
We got to the site early so we could set up our own equipment and help with the launch equipment. I was still working on setting up the weather station when other people, including the person towing the club trailer, showed up. With a number of people working on it, the range was set up well in time for the opening of the launch window at 10:00.
Vern Knowles, "parent" of the ever-popular "Kate", is working on making a version of her available for sale. Kate is an automated flight data reporting system that receives GPS data transmitted from a rocket and announces the details of the flight in near-real-time. Vern had prototype transmitters, pre-installed in various size nose cones, available for test flights at this launch. For various reasons I was the only person to take Vern up on the chance to give Kate a ride at this launch. Having Kate on-board meant I would not be able to include my Walston Tracker, which is installed in my usual nose cone. I was still able to fly my AltimeterOne, which meant I'd have two sources of data regarding my maximum altitude. The Kate nose cone is also heavier than my usual nose cone, so I anticipated a lower than estimated flight. Based on RockSim v9.0 my expected altitude was 6830' AGL. According to my AltimeterOne I reached an altitude of 6210', while Kate reported 6449'. Kate did lose GPS during the ascent, but reacquired a fix before apogee and reported data for the rest of the flight. It is a good thing she did, as I never saw Flying Colors after it left the pad. There were people that spotted it, but I think they were able to due to Kate's reporting. Since Flying Colors landed 1.33 miles from the launch site I probably would not have received a signal from the tracker if I'd been flying it, particularly after Flying Colors landed. With Kate having provided landing coordinates it was a simple matter of punching them into a hand-held GPS unit and walking right to my rocket. Thank you Vern for letting me fly your transmitter for you.
We infrequently have weather information, primarily wind speed, available at our launches. I own a wireless weather station that I've not been using much at home and decided that I'd see about arranging so I could transport it to the launch site and set it up. On Friday I picked up the hardware I would need to implement this decision and today I built it. I took a 56" length of 1010 rail that I acquired at a local recycling store, along with some accompanying hardware, and built a support structure I can attach to my Yakima roof rack system. I cut the 1010 rail into 36", 12", and 8" sections. I used the hardware to connect the 8" section at right angles to the 36" section. This forms the base portion, with 2.5" long, 1/4" carriage screws slid into both ends of the 36" and the end of the 8" section. These screws pass through clips borrowed from my bike rack to mount the base to the Yakima round bars. The 12" section is then mounted vertically, at right angles to both of the base sections. I used hose clamps to mount a 10' length of conduit to the 12" upright 1010 rail. The wind vane/anemometer of the weather station is mounted to the top of the conduit.
I assembled the support structure and mounted it on the car. Everything worked as planned. I'll probably mount the weather station's transmitter, which includes barometer, temperature, and relative humidity sensors, on the 1010 rail, but for today I just set it on top of the rail. After I had the system set up I went in the house to collect the receiver/display. Even in my office it was displaying the wind speed and direction, so I expect we'll be able to place the display on the LCO table and have it work, as I hope to do.
Presently I'm using a steel conduit. I had thought it was aluminum until I went to put it on top of the support. If I can locate an aluminum one I'll probably replace it in order to make the system easier to erect.
I also realized that I had to solve how to transport the conduit, since it won't fit in the car. That was easily solved though by using the hose clamps to fasten it along the 36" section of 1010 rail. We will need to be careful about opening the trunk of the car while the conduit is in this position. I think I'd better come up with some foam padding for the end of it, just in case.
Yesterday was our regularly scheduled launch day and the rocket gods smiled on us and gave us decent weather. We got stopped by a train across railroad tracks on the way to the launch site, so things were pretty much set up by the time we arrived. Our president had had to bring out the club trailer, meaning he didn't bring his personal trailer, which had his rocket tracker receiver in it. Since for now I'm borrowing his receiver when I fly my rocket, I was quite nervous about launching up over a mile and trying to find it. Given these considerations I decided to proceed with a flight, but use the I255 motor I had instead of the I303, since it was supposed to provide me a slightly lower flight. I armed my tracking transmitter and installed it in my nose cone as a precaution against my rocket going missing, the idea being that if I did lose my rocket I'd be able to go back out to the launch site with the receiver and locate it. I took my time prepping the rocket and ancillary gear so I didn't forget to do anything this time. I took my rocket out to the pad once I had it loaded up and inspected, but before I had everything else ready to go. I think I irritated some of the other rocketeers by tying up the pad for a while as I was getting everything else ready. I'll need to modify my preparations to make sure I don't do this again.
By the time I had video cameras ready to roll, GPS receiver up and running, and binoculars, camera, and FRS radio located and checked Coldfire was loaded up on the away pad and ready to fly. I re-situated my tripod mounted video camera so it could capture both Coldfire's and Flying Colors' flights. I asked Coldfire's owner if he would launch first so I could watch Coldfire fly without worrying about losing track of where Flying Colors landed. I don't think he understood my reasoning, but agreed and that is how things proceeded. It did prove to be a mistake in one regard in that I ran out of memory in my camera at the base of the launch pad prior to Flying Colors launching, so I have no video from it.
For this flight there was a high layer of thin clouds. This is exactly the kind of situation where I lose track of my rockets. I simply can't see them against the clouds. I think everyone lost it this time, so it may have actually gone above the clouds, but it is not clear. We watched and listened and for what seemed for an eternity there was no sign of Flying Colors. Finally somebody called out that they saw it and soon many people were tracking it. Eventually even I spotted my brilliant red parachute. In this case I think I would have been blind to not ultimately spot my descending rocket as it landed a mere 288.8' from the launch pad, per my GPS. I made the short walk out to it and did my usual post-flight inspection, including checking my AltimeterOne to see how high I actually flew. I was disappointed in this case to find that my altimeter had malfunctioned and was only reporting a peak altitude of 953' AGL. This was with the altimeter installed in my ported payload bay in the same configuration as the previous 5 flights.
I returned to base with my rocket and contemplated the skies. Soon we had a large patch of blue develop right over us and I decided to go for a second launch, this time on the I303 I had brought along as my primary motor. I reset my AltimeterOne and, hoping for better results, assembled my rocket. Since I already had my gear lined up from the first flight I was much quicker getting ready to fly when I took Flying Colors out to the pad. Soon the LCO gave the count and hit the launch button. Flying Colors flew beautifully up into the clear blue skies and I watched it from launch to landing. I walked straight out to it with no difficulty, though before I reached it I was really beginning to think I must have some how walked past it. It had landed beyond a small ridge and once I crested the ridge the parachute was easily spotted. I really didn't think it had landed as far out as it had, at 1244' from the launch site. I popped open the payload pay to see how my AltimeterOne had performed on this flight and found it reporting a perfectly normal looking reading of 6661' AGL.
So, with one small hiccup I had a really nice day of rocket flying with two successful flights of Flying Colors. In all there were 6 HPR launches, though I only managed to record 3 of them. There were a number of LPR rockets flown, at least one of which went AWOL. It was a rather detailed model, so I hope it can yet be found.
Here's hoping that I've met the blood and tears quota for my new rocket. I was sanding out the latest fiberglass work on the new airframe tube this afternoon. After getting the sanding to a point where I was satisfied I dry fit all the pieces together (fin can, 2 airframe tubes, 1 coupler, and nose cone) and showed it to my younger daughter. I had started disassembling the parts when my older daughter came out. I wanted to show her so started reassembling the rocket by attempting to insert the nose cone in the upper airframe tube. Despite the fact that I'd just had it all together and easily assembled and disassembled it, the nose cone wouldn't go in. In fact it got stuck and wouldn't go in or come out. I applied more force and suddenly it popped loose. Of course my elbows bent and the nose cone described an arc right into my face. Thank goodness I was wearing my glasses. They took a good bit of the energy and deflected the nose cone such that it hit my brow ridge. I still ended up with cuts on the bridge of my nose from my glasses and a puncture wound in my eyelid from the tip of the nose cone. That is far closer to losing an eye than I ever hope to come again. I'll be lucky if I don't get a black eye from this. So consider this an object lesson you need not repeat. If that nose cone gets stuck and you are tempted to apply more force to get it out, at least put on your safety glasses/goggles before doing so.
Today I undertook reinforcing the airframe tube and two coupler tubes for my next rocket. Like Flying Colors this rocket is being constructed from LOC/Precision 54mm kraft paper tubes reinforced with 3" light biaxial sleeve fiberglass from Soller Composites.
I started by fiberglassing the airframe tube as I did the practice tube that will be the second airframe tube in the new rocket. I once again used the treated shrink tubing to squeeze out excess epoxy using the process described on the Soller web site. I was able to strip the shrink tubing off by late this evening and I'm very happy with the results. Clearly the best of all the tubes I've done to date.
Once I had the airframe tube hung up to cure I started work on the coupler tubes. As can be seen elsewhere in this blog, I used biaxial sleeve to reinforce the coupler tube for Flying Colors, but while successful it was not a process without its problems. I had issues with the fiberglass pulling away from the inside tube wall if any force was applied that would pull towards the outer ends of the tube, as if the sleeve were a Chinese finger trap. It also kept pulling away from the tube at both ends where I had folded the sleeve back over the outside of the tube. These two problems tended to feed on each other as trying to correct one tended to result in the other being exacerbated.
While it is likely that using a vacuum bagging process would cure these issues, I do not have the equipment to implement such a process at this time. I have spent a fair bit of time thinking about the trouble I'd had and had come up with a possible solution that I decided to attempt implementing for these coupler tubes.
I started my new process by taping wax paper around the outside of the coupler tube in order to minimize transfer of epoxy to the outside of the tube. The wax paper was trimmed to match the ends of the coupler tube. Next the fiberglass sleeve was inserted into the tube. One end of the sleeve was folded back over the outside of the tube and secured with masking tape. This was done in order to restrain the sleeve within the tube while the remaining work was performed. The other end of the sleeve was not secured, thus essentially eliminating the possibility of the finger trap effect occurring, so long as I didn't pull on the sleeve from the unsecured end. I then used a disposable fiberglassing brush, available at your local hobby shop, to apply the epoxy to the sleeve, working from the end of the tube with the sleeve secured to it. I made sure that any force applied to the sleeve was a pulling motion towards the end of the tube I was working from. This forced the sleeve to expand against the wall of the coupler tube. Once I had all of the fiberglass wetted with epoxy I inserted a rolled up tube of waxed paper and then expanded it to contact the wall of the tube. I then inserted an uninflated balloon, purchased at the local party supply store, inside the tube, stretched the balloon to reach both ends of the tube, and inflated it with my air compressor. The balloon helped hold the fiberglass against the tube while the epoxy cured, while the waxed paper served as a release to keep the balloon being bonded to the tube. When the epoxy had cured to the gel stage the balloon was popped and the internal waxed paper removed. The fiberglass then received a rough trim and the external waxed paper was also removed. This process was duplicated for the second coupler tube and the tubes are now being allowed to fully cure before any further work is done.
The results are considerably better than I achieved on Flying Colors' coupler tube, with the fiberglass well bonded from end-to-end. There are signs that the internal waxed paper wrinkled and trapped some of the excess epoxy. Use of a proper release directly on the balloon would likely alleviate this issue. The balloons were also only able to exert a limited amount of force since the expanded outside the tubes as more air was blown into them. This limitation means that they didn't squeeze out as much excess epoxy as I would have liked. It is likely that the only cure for this would be to use a proper vacuum bagging process, however, use of a long balloon in place of the round balloon I chose to use my yield better results. I used the round balloon as I wanted the heavier walls such balloons tend to have. The photo album should help clarify the process.
After scrubbing last week's scheduled launch due to marginal weather conditions we got a "Go" for Saturday's "rain date." We got to the site with clear skies and cold temperatures. Once the sun got up for a bit it warmed up nicely and we had a great launch day. Shortly before noon I had a Cesaroni 649J335-15A loaded and was ready to launch Flying Colors on it's 5th flight. When the LCO pressed the launch button we were treated to a brilliant laser red flame, white smoke, and blue skies as Flying Colors leapt off the pad and raced to an altitude of 7588' AGL, setting a new personal altitude record for me. After recovering my rocket about 2/3 mile from the pad I spent much of the rest of the day shooting videos of other launches.
After scrubbing the last two weekends due to weather we finally got a "go" for launching today. Early in the day weather conditions were not very favorable for flying. Winds were coming from the north-northwest at approximately 15 mile per hour. Those rockets that were flown were targeting the 2000'-3000' range due to the winds and a low ceiling. I could have flown my Dragon Fly with the last of the G76 reloads I purchased last year, but with the cold temperatures I really didn't want to risk the non-ignition fiasco of our last outing. That meant I needed a much higher ceiling and preferably lower winds so I could fly my Flying Colors. The expected altitude for the smallest reload I had available, a Cesaroni 517I255-16A, was 6471'. After noon we started getting some blue patches of sky going over, so I prepared Flying Colors for flight with the I255 reload. When the next patch of blue rolled over us my rocket was launched atop a brilliant red flame and zoomed off into the sky. It weather-cocked a bit into the wind and deployed near apogee as expected. I had a long walk to recover it and discovered that my rocket had received new cosmetic damage, this time on both the payload bay and one of the fins. Due to paint transfer evidence it is obvious that the two parts collided, presumably during deployment of the recovery system. My altimeter recorded a maximum altitude of 6479'.
While waiting for a chance to fly my own rocket I shot video of a number of other launches. The videos will be posted to my YouTube playlist for the day as I get them processed.
Tonight I started work on a new rocket. It actually has been in process for a little while, but up to now it has been planning and parts acquisition. This is going to be a scratch built, 54mm, minimum diameter rocket using the practice tube I did before building Flying Colors and additional materials. I've purchased another LOC Precision 54mm airframe tube that I will fiberglass in the spring, once temperatures have warmed up. I have an Acme 54mm fin can that was picked up for me at the 2010 XPRS launch. I also just received a Performance Rocketry 54mm Von Karman nose cone that I ordered on a pre-Christmas sale. When I went to test fit this nose cone in the airframe tube I discovered that not all 54mm's are equal and the nose cone would not go into the tube. A quick check with my micrometer showed that the nose cone was 0.6mm too big, so tonight I took it out to my shop and carefully sanded down the nose cone until it fit into the airframe tube. Already this is starting to look like a cool rocket, but it has a long way to go.
Yesterday was the last launch opportunity for Tripoli Idaho for this year. Normally we don't launch on back-to-back weekends, but there were enough people interested in flying that we decided to take advantage of the last date we applied for in our FAA waiver.
We got out to the launch site and had overcast skies, though the clouds were higher than last week. Site set-up went well with many hands helping to get things done. Soon it was time to start thinking about flying rockets. I'd managed to acquire a reload for Flying Colors from one of the other TIR members who wasn't going to be at the launch. This was a Cesaroni 540I470-15A. As there was fog lurking in the Snake River canyon and obscuring some of the hills off to the North-West I was concerned that it was going to move down and sock us in, so I decided to get my flight off while I could, despite the grey skies. Once again assembly was very straightforward and I quickly had my rocket at the pad. I did have to borrow masking tape to secure the batteries in my tracker as my roll had been removed from my tool bag the previous week, Fail #1. In my haste to get the flight card to the LCO I forgot all about setting up my video camera, Fail #2. Consequently I have no video from this flight. Flying Colors made another brilliant flight, but once again I was unable to see the chute deploy. The winds carried it to the East, close to the same track as flight #2, but not as far out. I grabbed my GPS to get landing coordinates and couldn't get it to work as apparently the battery was dead, Fail #3. I recovered the rocket and found it to be in excellent condition, with no evidence of any damage from this flight.
After grabbing a bite to eat I started prepping Dragon Fly for a flight. In preparation for going out to the site I'd trimmed down what I would carry out and only grabbed one of the two G76-10G reloads I had available. In the process I'd failed to grab the grease for lubricating the O-rings and threads, Fail #4. I had to borrow grease to assemble this motor. Assembly was straight forward, but as I started to head to the pad I glanced at my work table and saw the container of black powder used to deploy the recovery system still sitting in the plastic bag the motor shipped in, Fail #5. I would have discovered this when I got to the pad and didn't have the cap to secure the igniter in the motor, but was glad I saw it when I did. I quickly rectified this situation and headed out to the pad. One of the other rocketeers was also flying an Arreaux on a G76G and had his at the pad ready to go. I asked if he'd like to fly his in a drag race with mine and he agreed. When it was time to launch his rocket launched while mine spit out the igniter, Fail #6. My competitor had already had 2 or 3 such failures on previous launches of his rocket that day.
Once Coldfire had flown I serviced Dragon Fly at the pad. I had to borrow a replacement Copperhead igniter, having left my spares at home along with my grease, Fail #7. I got the igniter installed and made another attempted launch. Again the motor failed to start and the spent igniter was spit out, Fail #8.
One of the other attendees expressed the opinion that the Mojave Green propellant used in the G76G motors is hard to light under the colder conditions we were experiencing yesterday. Based on the number of failed ignitions I'm inclined to believe him.
After this failed launch attempt one of the other participants launched his rocket, Thumper on it's second flight on a "K" class motor. In the video you can hear the motor come up to pressure, with a sound like a bottle being filled with water. Warning, if you turn up your volume to hear this effect the noise at launch will be very loud. This phenomenon is also audible in the Coldfire launch presented earlier.
As you can hear this flight ended horribly. The chute failed to deploy and the rocket descended ballistically and impacted disturbingly close to the launch site, landing just East of the North-South road to our East. The nose cone was buried about 1.5' to 2' into the ground.
I borrowed another igniter, this time a "home brew" one and prepared the motor yet again. I had gotten lucky on the previous igniter installation and managed to feed it through the nozzle without having to disassemble the motor. The new igniter wouldn't feed through the nozzle, so I had to remove the rear closure and nozzle. When I pulled out the nozzle it pulled up the fuel grains as well. I was a bit concerned by this, but decided the forward insulator and O-ring were undisturbed, so proceeded with reassembly. This time the Dragon Fly flew when the LCO pressed the launch button, unfortunately, due to a misconfiguration of the launch controller so did another rocket sitting on the next pad.
The Dragon Fly won this unintentional drag race, leaving the pads first, going higher, and landing last. This result was predictable however since the other rocket was a Level 2 certification attempt flying on a "J" motor. Bigger motors take longer to come up to pressure, so my little "G" motor launched quicker. The thrust-to-weight ratio also favored my rocket, consequently my higher altitude (expected: 2724.57995', actual:2863).
As can be seen in the videos, the skies improved during the day until we got a nice big blue patch above us. This allowed a Level 3 certification flight to launch on an "M" motor. The flight was awesome and successful, going at least 14,000'. I attempted to record this launch, but due to technical difficulties at the launch pad I ran out of battery power about 2 seconds before it flew.
After this flight there was a test flight on an "L" motor of a rocket that will be
flown in the spring for another rocketeer's Level 3 certification attempt. This flight also was very nice.
Saturday, October 30, was finally the day to put my new LOC/Precision Vulcanite H76 to the test and attempt to get my Tripoli Rocketry AssociationLevel 1 certification. If all went well I also intended to go for my Level 2 certification as well. We got to the launch site early so I could get our shelter set up before the other rocketeers arrived and it would be time to help set up the launch equipment. Precisely at 9:30 the other people started showing up and we quickly got the gear unloaded and set up. By shortly after 10:00 we were ready to go, so I started preparing my new rocket, Flying Colors for launch. For my L1 certification attempt I would be flying a Cesaroni 538I303-16A motor with the full 16 second delay. The preparations went smoothly and I soon found myself standing at the launch pad double checking my check list. This was the first time I'd flown a Cesaroni motor and I couldn't believe how easily it had gone together. With some trepidation I turned in the flight card for my rocket and when the Launch Control Officer (LCO) was ready to go quickly started the video camera rolling and got back to the flight line. Here is the launch, both at full-speed and at 1/30th normal.
After walking 1.21 miles I found my rocket in good order laying on the desert floor. Actually I should say that I found Jim, our local rocket finder, standing next to my rocket laying on the desert floor. After snapping some photos to document the condition of the rocket I opened the payload bay to check my altimeter. The altimeter reported a maximum altitude of 6732'. Pre-flight simulations had predicted 6735.91841'. Apparently it is unusual to have a prediction that close to the actual altitude as several comments were made about it.
I didn't initially find any damage, but when carrying it back to the launch site I noticed that I had lost some paint toward the leading edge of the sustainer, apparently from an impact with something. I had not initially seen it because it was on the side of the rocket that was laying on the ground. The underlying fibreglass and kraft paper tubing was undamaged, so I passed my L1 certification flight!
By this point the weather had degraded to the point that I could not attempt my L2 certification due to low ceilings. I grabbed some lunch and prepped my Aerotech Arreaux, Dragon Fly for flight. This is the rocket that was lost for nearly 2 weeks in the Spring on its second flight. I had not had time to paint it in the Spring, so this was the first time it would be flown in a completed state. I had acquired 3 Aerotech G76G-10 reloads for this rocket for use in the Fall launch window. I prepared the motor and was about half way through when I discovered that the reload kit had included the wrong igniter. There were actually three igniters in the package and all of them were too short to be used. Fortunately one of the other rocketeers was able to provide me with a a suitable igniter and I finished preparing the rocket. As I was completing the assembly of the rocket the skies decided to clear and it was obvious that I could go for my L2 attempt, but I didn't want to leave a loaded rocket sitting around and I could not unload it, at least not without compromising the ejection charge of black powder. I hastened to get the Dragon Fly launched and recovered so I could get going on the Flying Colors. Below are the videos for the Dragon Fly's launch.
Dragon Fly landed .34 miles from the launch site and achieved an altitude of 2948' vs. a pre-flight estimate of 2665.10535'. Recovering it was straight-forward, but ate quite a bit of time. By the time I got back to base we had clouds moving back in and I had to hurry to get my L2 attempt ready to fly. For this flight I would be using a Cesaroni 658J357-17A with the full 17 second delay. The ease of assembly of this motor really helped get me to the pad quickly, so quickly that I went through my check list twice again to make sure I'd not forgotten anything. With even more nerves than before I turned in the flight card for my L2 attempt. Again I started the camera rolling when I got the sign from the LCO and cleared the area. Flying Colors once again leapt off the pad and tore off into the sky. Below are the videos for this launch.
We lost track of it for a while but it was spotted coming down on the chute. While this was the highest flight of the day, it was also the shortest walk I had, landing only .34 miles from the launch site. There was no new damage. I took a picture of the rocket as it lay, but somehow I don't have it in the camera. Apparently I didn't get the shutter release fully depressed. I did open the payload bay to see my altimeter and have a photo of it, the only one I thought to take of it all day. So my highest flight to date has photographic record. The pre-flight estimate for this flight was 7408.37892'. The actual altitude was recorded as 7434'. This should have been my first supersonic flight with a predicted maximum velocity of 1180.7712 ft/s (805mph), but unfortunately I don't own the instrumentation necessary to verify that. Given the accuracy of the height prediction however, I strongly suspect that I achieved at least that velocity.
Below are photos taken during the day by my daughters and myself.
During yesterday's recovery system deployment test I observed some scorching on the parachute. Today I got better pictures of the damage. Nothing that will keep me from using the parachute, but I definitely have to find a way to ensure it doesn't happen again. The last thing I need is for my rocket to come down with the parachute going up in flames.
Today I finally got the recovery system ejection charge tested. I'd been concerned about the system deploying correctly due to how tightly it seemed to fit inside the airframe.
The first challenge to performing this test was the fact that while I'd managed to obtain a spent rear closure for my CTI Pro-38 motor case, I didn't have a forward closure to properly simulate the burn-out condition of the motor. The forward closure in these motors is part of the reload kit. Looking around my garage for something to fabricate a closure from I saw the can I'd been using to mix epoxy in for fiberglassing the airframe and fins. Fiberglassing the fins had in particular resulted in quite a bit of unused epoxy. I cut the can off the epoxy and then used a hole saw to cut a blank from the cleaner portion of the material. I mounted the blank on my hand drill and used this arrangement as a lathe to turn the blank down to the final diameter I needed. I also turned a shoulder on the part to insert into the front of the motor case. The hole saw left too large a hole through the blank, so I epoxied a washer with a small hole on the forward end of my pseudo-closure. I placed tape on the back of the washer before mounting it so that I was able to fill the central hole with epoxy on a second pass. Once the epoxy cured I drilled a 1/16" hole through the epoxy to simulate the hole between the delay charge and the ejection charge in the real motor. I applied double-sided outdoor carpet tape to the shoulder to secure it to the motor case once I had the ejection charge prepared.
I prepared a 1g charge of FFFF black powder by containing it in the tip of the thumb from a nitrile glove. I chose the thumb because I was able to obtain a large opening to pour the pre-measured powder into. Once the powder was in the tip the excess material was cut off. An Estes igniter was placed into the powder. One leg of the igniter was insulated with masking tape in advance of the insertion. Masking tape was used to gather the end of the glove tip together and tightly compact the powder. A drop of CA glue was applied to the opening to help insure it remained closed. The leads of the igniter were threaded through the 1/16" hole in the front of the simulated closure. The leads were restrained on the back of the closure by attaching them with double-sided tape after twisting them with the wires I'd be using to trigger the charge. More tape was placed over these weak unions to help insure they didn't separate. The wires had previously been threaded through the retainer ring, aft motor closure, and the motor case itself. At this stage the protective film was removed from the carpet tape and the simulated closure was stuck to the front of the motor case. Excess wire was drawn back through the motor and the rear closure attached. The assembly was then inserted into the rocket and the retainer ring installed. All that remained was to start the video camera recording, back off to a safe distance, and remotely trigger the charge with a 9-volt battery.
I finally finished the paint job on the Arreaux. I had it nearly finished and then screwed it up. It would have looked better than it does if I hadn't had to rework it. I still have a bunch to learn about spray painting I guess.
...Rocketry order delivered, equals one small step forward for me. I ordered my Cesaroni Pro38 motor case, delay adjustment tool and spacers from Giant Leap Rocketrylast week. The order was shipped last Friday, 3 days after I placed it. Today my order arrived. Everything looks great. My only complaint about the ordering process is a lack of transparency. After receiving confirmation for my order there wasn't any additional feedback. No order number for future reference, no shipment notice when the order shipped, or tracking information for the shipment. Since the order shipped USPS with delivery confirmation they could have at least sent the tracking number to me, though USPS doesn't show much in the way of information until after the package is delivered. I would certainly do business with Giant Leap again, despite my nit-picking.
On Friday evening and Saturday morning I worked on installing nuts for my railbuttons. I had gotten some special nuts from another local rocketeer that were supposed to embed in the wall of the airframe from the inside. Unfortunately they were not intended for use in kraft paper tubes and wouldn't seat. I ended up having to epoxy them into place which was rather tricky, since the forward nut was nearly two feet down the inside of my 2+" tube.
On Sunday I got back to work on the rocket and got the payload and nose cone mostly painted. I got the airframe primed. The photos show the airframe ready for painting, with bolts threaded into the nuts to keep paint from getting into them and tape over the bolts to keep them from being stuck to the nuts.
I finished sanding out the fillets on the fins and decided to get going this evening on the reinforcement of the fins. I set up the airframe on my workbench and applied fiberglass to one side of one set of fins. This time I applied the epoxy before applying the fiberglass. I still had to apply epoxy to the fiberglass after I laid it on the rocket. Unfortunately I'm going to have more sanding to do as the epoxy has obviously settled into the area of the fillets. I'll also have to apply more epoxy to fill the texture of the fiberglass after the current round of epoxy has cured. I'll only be able to do one side of one fin at a time as I'll have to have the fin horizontal while the epoxy is curing. I'm going to first get the glass applied to all three sides of the rocket before I tackle this step. The thing I hate most about it is how wasteful it will be of my epoxy. I have to mix a full pump up and won't come close to using it all. I don't have any projects waiting in the wings that I can use excess epoxy on either. :-(
On Friday afternoon I installed the centering rings on my engine tube. Since I plan to install an Aero Pack Engine Retainer I had to alter the assembly instructions slightly. The instructions call for the centering rings to be mounted 1/8" from each end of the engine tube, but the motor retainer requires 3/8" for mounting. I checked the fit with the rear centering ring moved 1/4" forward and found that that puts the forward edge of the ring right at the back of the fin slots in the tube, so proceeded to assemble the engine tube in this configuration. I then prepped the bad area of fiberglass on my payload bay tube for patching by sanding out the bad area and feathering out the surrounding area.
On Saturday I fiberglassed, patching my payload bay tube and adding a layer of the fiberglass sleeving to the engine tube between the centering rings. The primary motivation for adding the fiberglass to the engine tube is to account for the extra thickness of the airframe tube when mounting the fins. There is an added benefit in that the fiberglass should also strengthen the connection between the engine tube and the centering rings.
One of these days I will learn that fiberglass doesn't like making 90° bends. I cut the sleeve for the engine tube quite a bit longer than the tube in order to allow for fraying as I worked the sleeve over the centering ring and stretched it out on the engine tube. I thought I'd be able to bend the sleeve up along the centering rings. This proved harder than I anticipated. Once I had my epoxy applied I found that I couldn't keep the fiberglass in contact with the tube as it approached the centering rings. I had a length of the shrink tubing available that was the right length, but I couldn't see how I was going to keep it from contracting lengthwise while I shrunk it as the centering rings would keep me from holding it with my pliers. I decide that I had to try using the tubing anyway, as I wasn't getting what I wanted without it. When I tried to pull the shrink tubing on over the engine tube the fiberglass pulled off the engine tube and ended up a wadded mess inside the shrink tubing. I pulled the shrink tubing back off and straightened out the fiberglass. I ended up doing this twice as a second attempt yielded the same results. I finally resorted to cutting two lengths, each about 1" in length, from the shrink tubing and working them onto the engine tube. After sorting out the fiberglass yet again I put one at each end of the engine tube and shrank them in place, using my stirring stick from my epoxy to push the tubing sections towards the centering rings as I heated them. I did a better job of this apparently at the forward centering ring than at the aft one. The finished product has a fairly tightly radiused curve in the glass as it transitions up onto the centering ring with the gap under the radius filled with epoxy. At the aft end the radius isn't as tight and there are areas that are not epoxy filled.
On Sunday I installed the engine tube in the airframe and proceeded to install the fins. I had to use my Dremel with an engraving cutter to cut out the radiused fiberglass at the aft centering ring in order to get the fins to insert into the slots. The poor bonding at the aft centering ring worked in my favor in this case, making it easy to remove the obstruction.
On Monday I used Loctite Repair Putty to form fillets between the fins and the airframe. I worked on sanding out the fillets, but ran out of time. More sanding tonight.
I sanded out the bulge in the fiberglass on the payload bay. Almost as soon as I touched it with the sand paper it disintegrated, leaving a nasty void in the fiberglass with epoxy underneath. Now I have to figure out how to fix it.
I sent an email this morning inquiring about the refund for the nitrile gloves I cancelled from my order. About 3 hours after I sent the email I had a reply stating the funds had been refunded to my credit card. They haven't shown up on VISA yet, but I assume it takes time for them to process the refund to my account.
So today was the day to strip the shrink wrap from the practice tube and see what I had. I'm not completely happy with the results. As you can see in the photos there are areas the appear to correspond with where I started heating the shrink wrap that are not bonded to the underlying tube. The areas are also rough when compared to areas further away, as if there is significantly less epoxy in them. My first impression was that I may have held my heat gun on these areas too long and somehow caused this.
With this information in hand I proceeded to glass the real airframe and payload bay tubes. I decided that the easiest way to do them would be to mount them up adjacent to each other on a single PVC pipe, with a small gap between them. I then slid the fiberglass on them and secured it. When applying the epoxy I again found myself working excess fiberglass down the length of the tubes. Apparently the epoxy is acting as a lubricant and allowing the glass to slide along the tube and I suspect even more importantly along the weave.
I made what I feel was a mistake when I started putting the shrink wrap tubing on. Without thinking about it I started sliding the tube on from the end that I had worked the excess fiberglass down to. As I was pulling the tubing up I started seeing the fiberglass come off of the airframe tube as I was obviously pulling slack up the with the shrink tubing. I stopped and pulled the shrink tubing back off and then pulled it on from the opposite end.
I made sure my heat gun was on its low temperature setting to ensure I didn't overheat the fiberglass, due to my impressions from the practice tube. I shrank the tubing without any apparent complications until I got down to the payload tube. There I had a bulge that I could not get out.
I hung the tube up and let it cure. I then grabbed the practice tube and sanded it with 80 grit paper to prep it for a layer of epoxy per Soller Composite's recommended process. With the tube prepped I applied the epoxy and hung it up to cure.
Next I took the coupler tube and used the fiberglass sleeve to line it. This proved to be somewhat tricky, as the sleeve's natural tendency is to contract, not expand (think Chinese finger trap). This proved to be a real problem after I applied the epoxy. I ended up working the fiberglass until the epoxy got very tacky in order to get it adhered to the inside of the tube. Any force that pulled toward the ends of the tube would cause the sleeve to contract and pull away from the tubing. The ends absolutely refused to bond, particularly the end where I'd started applying the sleeve and had come hard around the end of the tube. It finally got to the point where the epoxy was so tacky that attempting to manipulate the fiberglass any further was doing as much harm as good due to it attempting to adhere to my glove.
Late in the day I was able to use the coupler tube as a gauge and determined that I could strip the shrink tubing from the airframe and payload bay tubes. I was really eager to do this in order to see my results and investigate the bulge on the payload bay. As you can see in the photos the bulge is an area that is not bonded to the underlying tube. My conclusion at this point is that when I smoothed the fiberglass back out after pulling the shrink tubing on from the wrong end that I missed a spot. I thought I had it all, but the evidence speaks for itself.
The main airframe tube looks great. I applied scotch tape over the pre-cut fin slots in order to prevent them getting filled with epoxy. It looks like I left a scrap of tape on the tube, though I really don't remember it. I don't see this as a real problem.
I don't think I'll be able to repair the bulge on the payload bay tube. I do have a solution though. The practice tube has plenty of good sections, so if the original payload bay is unsalvageable I'll cut a new one from the practice tube.
