Eric Truax Holiday Bell (Plan)
Contributed by John Lee 
Brief: The 2009 Holiday Bell is Erik Truax's Christmas gift to the rocketry community for 2009. It is a rocket powered
flying model of a Christmas bell. He offered downloads of the plan on TRF and must have had substantial response
because all attempts I made to download it were met with a server error stating that the maximum downloads had been
reached. He was kind enough to send me the Zip file for the rocket and I immediately thought that putting it together
sounded preferable to filling out end of year paperwork. Construction: I began the process by starting to cut out the various pieces and gluing them together to form the various "rings". First up for me was the "aft bulkhead" which is actually the interior surface of the bell. It was nice because it had a minimum of "shark's teeth" to deal with. This and all other parts were cut out with a fresh X-acto with the piece lying on top of one of my wife's butcher plates. (Don't tell her!) When it was cut out, a very light coat of white glue was applied to the glue tab and it was glued together to form the interior cone.
I next turned to the conic section that would be second from the top. It was chosen because it happened to be the next one I picked up. Again, there were not too many of the teeth to cut out and, once cut, it was glued along the tab line. The top section came next for much the same reason. It also had a lug hole to cut out. The main body of the bell came next. By this time, the teeth were becoming tedious and I adopted a procedure of making all the cuts in one direction first and then trying the other. It seemed to help. The bottom rim of the bell was the most tedious part. It had teeth along both edges. In time,though, it too was cut and glued, just in time for me to do the Christmas Eve service at my church.
The "body tube" of this rocket is actually the bell handle. It was fairly easy to cut out since it is essentially a rectangle with some glue tabs. Since rolling paper tubes is a known weakness of mine, I decided to pre-roll the handle around a wooden dowel of smaller diameter than the actual handle is supposed to be in order to get the final handle to holds its shape more easily. The handle was then glued into a tube at the marked line.
As the glue on the NC petals was drying, I cut out the band that would form the shoulder of the nose cone. The band was then glued into a loop using the marked line to determine the circumference. While that set up, I applied a little glue to form the 4 lobes of the cone into two, giving it an even more pronounced curve. That was given an hour to dry and then the final two sets of tabs were glued into place to finish forming the leader surface. A coating of white glue was also applied to the inside of the cone to strengthen as help to seal it a bit.
Fortunately for me, I had the presence of mind to test fit the shoulder band of the nosecone into the body tube (handle) before trying to affix it to the nose cone. It was too big and did not fit either because I had rolled the tube too tightly or because I had not rolled the band tight enough. A check with a spent motor casing revealed a bit of both. The motor was tight but did fit. I cut a slit out of the NC band and reglued it with a tight but not too tight fit. When that had set, some glue was put on the sawtooth tabs of the band and it was fixed to the cone proper. The launch lug intended for this project is hand rolled from the same cardstock as the rest of the project. To me, that did not sound fun and I cheated and glued on a piece of 1/8" lug I had sitting around.
The instructions for the Holiday bell leave the builder to make decisions about the shock cord system but do say that Mr. Truax recommends elastic attached by means of a slit as some of the old Estes designs use. I went with a trifold and a piece of Kevlar® because I happened to have it sitting handy. One end of the Kevlar® was knotted and then glued into a very ugly trifold cut from a piece of the instructions already used. The mount was then glued into the tube using a 1/2" bolt to press it into place. The other end of the Kevlar® was also knotted and then bent double into the NC. A large glob of white glue was then poured in to fix in into place.
I test fitted the aft bulkhead with the handle and slid them into the bell to take note of where everything would line up. Some glue was then applied to the handle and the bulkhead was glued in place to the handle. When the glue on the handle was dry, I slipped it back through the bell and began the process of gluing the teeth to the bulkhead a few tabs at a time. A clamp was used to hold everything in place as the glue set. Towards the end of the process, I found that my alignment had not always been as good as it should have been. I found myself using a larger clamp to pull thing back to where they were supposed to be and that led to its own warping. After that, I applied some white glue fillets where there were gaps or things looked weak and the Holiday bell was ready to fly. Finishing: Construction Rating: 3 out of 5 Flight: At my recent makeup launch it was one of 2 rockets that HAD to be flown. For the maiden flight, I located a piece of streamer, cut it to size and tied it to the Kevlar®. I then selected a B4-4. I had to strip some of the paper off but I got it in and then let Tiger hook it up. It was his first time. We had to wait while Todd's Ricochet took off... ...then I got bogged down with something and had to let Andrew's Sky Dart XL take my turn. Of course Tiger wanted to help Andrew retrieve his Sky Dart and Andrew was generous enough to allow him to do it so that Stu's Titan III Dyna Soar slipped in ahead of me. Due to stability issues, retrieving the Dyna Soar was not an option so, at last, it was my turn. The bell actually looked pretty good under thrust and was one of the straightest flying rockets I have ever flown. It decelerated quickly after the thrust ended and began to tumble down. Then the nose cone popped and the streamer deployed and the rocket drifted safely down. Since Andrew had already set the example, I decided to let Tiger and Lindsey run out to retrieve the rocket...good as new!
Flight Rating: 5 out of 5 Summary: Overall Rating: 4 out of 5 Other:
What You Can Do
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While
the glue set up on the bell and handle portions, I turned my attention to the nose cone. I started out by using an
X-acto to cut out the floral shaped piece that would be folded into the cone. For my clumsy fingers, it was an exacting
process. When it was cut out and I had shaved off the excess paper as best I could, I applied a touch of white glue to
the tabs of 4 of the cone sections. These were not four adjacent panels but 4 spaced out to form a cross. These four
pieces were then mated to the adjacent panels, turning the piece from a 8 petaled flower into a 4 petaled one. This
order was adopted based on the recommendations in the instructions and made putting the cone together much easier than
it otherwise would have been.
Messing
with the nose cone gave a chance for the various rings to dry and they seemed ready to assemble. The instructions
reveal that alignment of the bell sections is achieved with a series of tick marks that are aligned with seams. With
that known, I began to put the sections together, putting a little white glue on the shark's teeth and gluing a little
bit at a time. When that was dry, I would do a little more. When the first two pieces were together, I started on the
next and found that a little clamp was helpful. Then came the top section which was slowly glued in place in the same
way.
While
the glue on the handle was drying, I took a pair of needle nose pliers and bent back all of the shark's teeth around
the bottom of the bell to prepare it for receiving the bulkhead.
About
this time I noticed the paper band for the thrust ring still sitting where I had forgotten about it. I never intended
to roll my own. Instead, I cut a ring from a spent 18mm casing. Because my handle tube was a bit tight, I had to peel
some paper off the ring. Some glue was then swabbed into the tube and another casing was used to push the ring into
place. This helped to pull everything back into round again.
I finally got
to fly my bell.
The
second flight of the Holiday Bell was with an Estes C6-5. It was prepped with minimal wadding and taken to the pad
where it was supposed to fly right after Andrew Cooper's Extended Payload A.S.P. Andrew was up first and commenced his
countdown and all were watching his A.S.P. All were surprised when my Bell took off instead. Andrew had activated the
correct circuit but the leads had been switched out at the pad. I was a bit startled so I did not get many photos of
the flight. I can say that it was another performance like the previous one where it flew well and straight with a
quick deceleration after the boost phase. When it ejected the streamer came out and and it drifted down pretty close to
the pad again.