S.L.R.
(Shugo's Last Ride)
This rocket is a little different than most of mine in that it has a bit more meaning. Because of this I had a difficult time deciding on an airframe/rocket that I wanted to use for this project.
This rockets first flight will be for our beloved Shugo, and will take some of his ashes above and beyond so as to be his last ride, where they will be scattered at apogee. Shugo was a special boy to us whom we couldn't save and who's story is to big to go into here. Suffice to say he meant the world to us and I couldn't stand the idea that his last ride was to a vet's office to be PTS, so I've decided this will be his true last ride.
I had a couple ideas at first, one was a large airframe that would make a good canvas for a custom paint job, one I thought about using to mimic Shugo's colors. This would be a difficult task but I considered it for a long time.
The second was for a slightly smaller framed bird that would get much more altitude and take him for one hell of a ride, I went with this idea and have decided to go for a memorial paint scheme in black and silver, also the bird I chose is a solid fiberglass frame, very stout and very strong just like Shugo boy, and I built it like a tank as you will see so as to handle any 75mm motors out there.
The kit I chose was a Performance Rocketry Competitor 4 rocket kit, all fiberglass components, 4" diameter and just shy of 8 ft tall, (94"), 76mm motor mount with the AeroPack tailcone retainer.
My first step was to take all components and weigh them individually and enter these weights and the rocket build into Rocksim and start simulations. This bird should be able to fly on J through M power from 4,000' up to and above 15,000' depending on motor choice. First flight motor has yet to be decided at this point.
The first step in the build was to sand down all components at all points that would have a glue joint, this included the fins, motor tube, booster tube, nosecone, avionics bay, centering rings and bulkplates.
After this was done I had to figure out both motor retention and how to secure the recovery harnesses in this close to minimum diameter rocket.
All though expensive and I've never chosen to go this route before I began looking at the AeroPack motor retainers, this is one flight that to me personally is as important as my L3 flight and I want the least amount of chances for anything to go wrong, so another $50+ was spend and I ordered the AeroPack tailcone retainer, 76mm to 4". Generally I've gone with Kaplow type clips I've made myself for retention but this particular bird doesn't leave much room for them so I felt this was the best way to go.
Motor retention was taken care of, now to attachment of the recovery harness in the booster, again not a whole lot of room here for eye bolts or U-bolts to attach to so I came up with something similar to what I did in my Mach 1 rocket.
I took an 8' piece of 1/2" tubular kevlar and fashioned this attachment. The tubular kevlar goes underneath the middle centering ring which will be seated down against the fins, and over the outside of the top centering ring, both places sandwiched between either the airframe or motor tube, then procedes out of the booster section loops back down into it and repeats the same attachments on the other side to creat one long loop. I had to dremel in a very slight notch into the centering rings to allow the tubular kevlar to fit in place. Now that was taken care of and time to start building.
Having everything sanded down and ready to go I proceded with building and making my first mistake. I started out with JB Welding the retainer collar to the end of the motor tube. I then went to bed to let it setup over night. About 2 in the morning I woke up and started thinking this wasn't going to work, I wanted this built to my usual tank specifications which meant centering rings were to be coated on either side with epoxy, with this retainer welded on first, I wasn't going to have access into the rear of the booster section to do this or to fillet the fins, so I was up at 2am cutting the retainer off the motor tube.
After cutting it off and another hour of work with a dremel cleaning out the JB Weld from the retainer I had the retainer collar salvaged and my mistake realized.
After that close call it was time to start building again. The way I wanted it build meant the fins had to be attached before the centering rings were epoxied in place.
So I placed the middle centering ring on the motor tube about a half inch above the fin locations, then inserted the motor tube into the rocket, placed the bottom centering ring onto the motor tube about a half inch below the fin locations, then placed the retainer collar and the tailcone retainer in place on the motor tube to insure proper measurements for these pieces.
After that I mixed up small batches of JB Weld and tacked the fins in place. After these had set overnight and fully set I took the middle centering ring and with a wood dowel tapped it down into place seated tightly on top of the fins. Then the bottom centering ring and motor retainer hardware was removed.
With the middle centering ring seated firmly against the fins the rocket was inverted and I then made a poor of Aero Poxy down between the airframe and motor tube onto the centering ring, this was a big poor of 15cc's of epoxy with 5cc's of milled fiberglass added for strength, this then tied the fins, airframe, motor tube, and centering ring all in together in that pour.
Above the centering ring is in place with the epoxy poured and is now curing, you can almost see through this fiberglass stuff and if you look closely below the fins you can see the ring, it's now double in thickness because of that large poor.
It was then time for internal fillets on the fins.
Before the fins were tacked on they were sanded with 60 grit to assist in adhesion of the epoxy and I also went back to one of my old tricks and drilled the fins on each side. 4 holes were drilled halfway into the fin along the root edge so that the epoxy could fill into the holes and form epoxy nails.
There wasn't much room to get those fillets in there, only a half inch of room and I wanted to make sure the entire fin root was covered well so I ended up using a syringe with some fish tank air tubing to reach into there and get the epoxy where it needed to be.
Each fin has one internal fillet on each side, each fillet consistes of 15 cc's of Aero Poxy again with 5cc's of milled fiberglass added for strength, this amount was enough to coat the fin root and create sufficiently heavy fillets all the way from the motor tube to the airframe tube.
The internal fillets are now drying, the picture angle is bad so it doesn't look like it but I poured the fillets, evened them out and all the way to the bottom of the fins the way I wanted them and then placed the rocket in these towels to cradle it, I then used a level to every so slightly tilt the front of the airframe down, just enough to keep the epoxy running to the back end and getting in the way of the rear centering ring.
After all the internal fillets were complete and cured I then mixed up another batch of epoxy, again same amount which seemed to stay constant through out the build, 15cc's epoxy 5cc's milled glass, I poured this into the booster tube in equal amounts between each set of fins, then tapped the rear centering ring into place quickly and then set the booster section upright on it's bottom end so that it would then flow down and coat the bottom centering ring and tie all the parts together.
Since it was in this position now I went ahead and also coated the top of the centering ring that was on top of the fins, again with the same amount of expoxy and milled glass.
Here you can see the syringe I was using, it's attached to a length of air hose for the fish tank upstairs, hope the fish didn't need that hose........... hmmm
A note here, when using milled glass, you're better off sucking the epoxy mix up into the air hose rather than pouring it into the syringe and forcing it down, it ended up clogging the syringe nozzle because of the milled glass, it seemed to congregate there at the nozzle, when I sucked it up into the air hose which has a much bigger I. D. it worked fine.
After the epoxy had cured on those centering rings the top centering ring needed to get epoxied into place. I made another epoxy pour into the airframe from the top, then pushed the top centering ring down the airframe and over the motor tube, remember this all had to be done while working with the recovery harness keeping it all lined up, it was a bit of a feat to say the least but I got it in place and then flipped the rocket over so that the epoxy would run down and coat the bottom side of the top centering ring.
While it was inverted again I also coated the bottom side of the bottom centering ring. Here you can see the middle and bottom centering rings through the airframe tube on either end of the fins. They're both about 3 times thicker now because of the added epoxy pours.
When this was cured the booster tube was again flipped upright and the top side of the top centering ring was coated. All of these centering rings were sanded down well with 60 grit for better adhesion.
Keeping track? We're up to 180cc's of epoxy thus far mixed with 60cc's of milled fiberglass.
After all of this had cured and set I then at the right time, JB Welded the retainer collar in place on the end of the motor tube.
Now it was time for external fillets, and I've always liked them sufficiently big and strong so again the fins were drilled with holes for epoxy nails and sanded well with 60 grit, each fin received a fillet of 15cc's of Aero Poxy with 5cc's of milled glass added for strength.
External fillets being poured.
I don't know what i was doing with the picture angles here but again that booster tube is leveled so that the epoxy settles out evenly along the fins.
Here again you can see the 3 centering rings now in place and epoxied in and much thicker now.
Next the nosecone bulkplate was fitted with an eye bolt and fender washer/nuts. It was then epoxied into the nosecone with a full batch of epoxy (15cc + 5cc) on the top of the bulkplate and the bottom.
I had already sliced a 1" section of airframe tubing off the top of the booster section and this was now epoxied to the center of the 11" long coupler tube for the avionics bay.
I like the way the bay was setup for this kit, with the 11" piece of coupler tube and then bulkplates for each end for both the coupler tube and airframe tube to make caps for the ends.
You can see the avionics bay here and the end caps. It's held together with one piece of 5/16" allthread and then 5/16" U-bolts on each end through the caps. Each bulkplate was 1/8" thick G10. The sled inside was also a nice full width G10 sled for the altimeter/altimeters.
I still need to setup and wire the sled at this point.
Now that all of this epoxy has been poured and set all parts were then placed into a curing oven and hit with 150 degrees for a 3 hour cycle to finish off the curing and strengthen the epoxy.
Here you can see the external fillets fully cured now, as well as the Aero Pack motor retainer.
The entire rocket complete minus paint. The nosecone will be retained by friction fit as well as 3 2-56 nylon screws for shear pins. The booster section will be shear pinned to the avionics bay as well. Avionics bay to the payload bay will be attached via 4 plasic rivets.
At this time I need to wire the avionics bay, attach standard rail buttons and drill some pressure relief holes and it will be all set.
I have a black/silver paint scheme with some graphics to include a head shot (picture) of Shugo that will be going on the rocket and then we'll be all set. This is my first bird that will be professionally painted and I'm in the process of getting that worked out now.
Stay tuned for pictures after paint, should be up within the next few weeks.
Painting
After 7 coats of primer and allot of sanding it's time to apply some paint. The colors I want are Black and Silver, however silver spray paint can be a pain to work with but I was willing to try it as it was what I wanted.
After the first attempt, everything looked good except for some imperfections in the fillets that I didn't catch during prep, so I stripped the whole thing down, fixed those and started over. Again after allot of primer and sanding it was ready for the second attempt at silver.
And on this second attempt I nailed it and got just what I wanted. Unfortunately I made a mistake and clear coated too early, I was a bit testy after that as the clear coat crazed, or spider webbed all over the silver.
So for the second time I had to strip it all the way down again.
Finally however I got it done the way I wanted, gave the paint 4 days to set and then clear coated it and it held fine. $40 worth of decals later it was time to get it finished up. I think the sign shops here make a killing personally.
Painted, clear coated, and decaled.
Once I can get some sunny weather I'll retake some pics, as the cloudy weather just doesn't show the paint very well.
Some simulation information.
I've still got to add in epoxy weight, for those interested, I mixed a batch of epoxy and let it fully dry and cure, 15cc's of AeroPoxy with 5cc's of milled glass added and then weighed it. This batch weighs in at .8 oz wet, and then after it dried it was .7 oz. Works out to be a 12.5% reduction in weight when dry.
General sim info.
Motor sims. She'll fly nice on anything from an I600 on up to the M1400 breaking 1,000 MPH.
Flight 5-21-06
We were finally able to make the maiden flight on 5-21-06 with TQC in Walcott, Ia.
One of those days where everything seemed to be a challenge but eventually worked out ok. When we got up early in the morning it was way too windy, but a check of the forecast indicated that the wind was supposed to die down around 10 am so we made the decision to go.
When we got to the launch site around 9 am the wind was still going strong, after waiting 2 hours it seemed to finally start showing some signs of letting up so the decision was made to prep and get ready to fly hoping it would continue to die down.
By noon the wind had finally let up sufficiently that I was willing to go for launch. After prepping the electronics bay with dual Missile Works RRC2's for control of the recovery system we began assembly of the recovery systems.
I still wasn't happy with the fit of the R12, and made a last minute decision to purchase a SkyAngle Classic 60 for the main, some help from Justin Farrand, (read here he packed the chute for me) and I was much happier with the fit of the main.
Upon completing the booster section it was time to get Shugo on board, at this point there was a bit of emotion but I didn't cry, I just got some dust in my eye.
After that the main was loaded and the rocket prep was completed.
A check with Tim found my motor of choice in stock so it was purchased and then assembled. The CTI K510 a 75mm K was loaded into the rocket and the tailcone retainer installed.
Shugo and SLR were then taken out and put on the pad and readied for launch. Both Alts had good continuity and we were ready to go.
Time for a few quick pictures first.
S.L.R. on the pad, myself and my number one rocket helper Meesha ready to go.
I'd chosen the CTI K510 for a couple reasons, it's flight profile with this bird was what I wanted, and most importantly the reputation of reliability with CTI motors played a big part, quick starting and always going off without a hitch which would make getting good video and pictures easier.
However like I said it was one of those days that nothing seemed to go just right. I'd made mention at the RSO table that if this flight to go off ok I was done with rockets. What no one seemed to really understand was the importance of this flight to myself, and the rest of my family, I did everything I could to insure it would go well. The RSO didn't really like that comment....knowing that nothing is guaranteed with these birds, but it's the way I felt, this flight was more important to me than my L3.
We were ready to go, cameras everywhere were ready as well as video were ready, so after the countdown, the button was pushed, and then the next hiccup.
The ignitor lit, and the motor began to fizzle, a strange noise and for two full seconds, past the buffer range of basically all of the cameras at the launch the rocket sat there like picture above fizzling. The ignitor was installed as per the instructions using the supplied "standoff" to keep it at the top of the motor but it seemed that the bottom of the motor had lit.
My heart sunk as I was instantly certain that it was going to burn up on the pad. I've seen it before and couldn't understand how the bottom lit first. After more than two full seconds somehow, the motor pressurized, it seemed almost as though there was some intervention on the flight...
Photo credit Tom Farrand
Finally pressurized S.L.R. started up the pad.
Photo credit Tom Farrand.
When it did come up to pressure she was off, how much of the motor actually burned off during that time I don't know, but the flight was nice. At the top she arced over and the RRC2's did their job firing the apogee charge and Shugo got out for a beautiful view of the springtime landscape.
Altitude was reported at 7,611 feet. Shy of the 8,500 predicted but I do believe what burnt off down on the pad may very well have been enough to make up the 1,000 difference.
Again emotions ran high but it was a nice flight for Shugo.
Falling drogueless down to 1,000' the RRC2's again performed flawlessly and ejected the SkyAngle main which caught air instantly and gently lowered S.L.R. down to the ground about a half mile away.
Upon cresting a small hillside on my way to recover S.L.R., the next hiccup. At the bottom of the hill was a small waterway and it appeared from my vantage point that I probably landed right in it.
As I approached the rocket I found it layed out with the very tip of the parachute hovering over the water and the rest layed out to the north away from it. Another little scare.
Overall everything worked out, and somehow allot of the way the day went reminded me of Shugo, always just a little difficult.
Sweet ride Shugo, we miss you.