Build session report, Troop 232, Lino Lakes (10/16/2010)
On Monday I attended the weekly troop meeting of Boy Scout
Troop 232 at the Living Waters church in Lino Lakes. I helped 9
scouts built various Level 1 kits from a Custom Rockets Variety Bulk
pack. It contained various SL 1 kits based around BT-50 (24mm) size
body tube, 18mm motor mount, 4 fins and 12 inch chute. They are all
similar to size and shape of an Estes Alpha (with an extra fin!).
I did not pick the kits. The Scout Master had ordered them. While
the kits from Custom are great SL 1 rockets, they are tough to
finish in a 60-90 minute build window. The following problems arise
in trying to get these done that quickly:
1. Custom still has die-crunched fins. This means the kids have to
finish cutting them out.
2. Die-crunch fins require more sanding than laser cut fins
3. It takes time to build the 18mm motor mount for a BT-50 rocket.
These mounts use 2 centering rings, motor clip and motor block. You
have to build it and then let it dry long enough to slide it into
the main body tube w/o moving the centering rings on the motor tube.
4. Custom has you assemble the 12 inch chute in the same manner as
traditional Estes parachutes (cut out the plastic, cut and attach
the shroud lines)
5. These are 4FNC vs 3FNC models. Takes time to attach that 4th fin
6. You have to cut out body tube marking guide and shock cord mount
(Estes type paper mount glued to inside of body tube)
I knew what the kits were going to be ahead of time so I did the
following to try and speed things up a little bit:
1. I pre-cut 12" lengths of Kevlar shock line. I had the scouts
attach the sock line to their motor mounts and the supplied elastic
shock cord a-la Quest. This avoided the need to cut out the shock
cord mount and glue it in.
2. I brought along several of the yellow plastic tube marking guides
from the Estes tube marking and cutting kit. I had 3 to bring. This
was faster than cutting out the paper tube marking guide, wrapping
and taping it to the body tube and marking from that.
3. I got a 36 inch length of 3/8" Plastistrut V-channel and cut it
into 4" lengths. These are great to use to mark the fin alignment
lines on small body tubes. They are self-aligning. I didn't have
enough of the Estes tube cutter/markers to go around so this was
quick and easy.
4. I used VCP (it was handy) to print out fin alignment guides for
BT-50 based, 4FNC rockets with 3/32 fins. I glued these to pieces of
cardboard. I cut a couple of the guides out myself and got some of
the adults at the troop meeting to finish cutting them prior to the
start of the meeting. These are great bot both holding the fins on
the rocket and keeping then perpendicular to the body tube.
5. I use fast drying yellow glue and kept reminding the boys to
apply THIN layers of glue to let then set faster. I also had then
pre-glue both the fin roots and body tubes right after the tube
marking was done. Then when they applied the fins they reglued the
fin roots, waited for a minute or so, attached and held for 30
seconds, and the fins were tacked into place.
Even with the above, I think only one of the boys building 4FNC kits
finished. All told we only have about 65 minutes of build time
during the troop meeting. However, I let all the boys take home the
plastistrut tube markers and the cardboard fin alignment guides. My
attempts to 'save time' helped overall but there are things I
realize I could have done differently that would have saved even
1. I saved time by the boys not cutting out paper shock cord mounts.
I lost time diverging from the instructions to explain the alternate
process of attaching the Kevlar line to the motor mount and elastic
shock cord. Next time, I will just print and cut out a bunch of
paper shock cord mounts and bring those. Saves the cutting time, the
boys don't cut out parts of the instructions and I don't have to
worry about Kelar line.
2. I saved cutting time using the Estes fin marking tools but lost
time because the boys had to sharer a couple of them. Plus, I was
again diverging from the instructions. Next time, I will just print
out fin marking guides using VCP. Between #1 and #2 all of the paper
cutting time gets eliminated and we can just follow the instructions
all the way thru.
3. Attaching 4 fins takes more time than 3 fins. I would print out
both 3-fin and 4-fin marking and alignment guides and suggest they
build the rockets as 3FNC.
Despite not quite finishing, the boys all seemed to have a great
time building. It was obvious this was the first glue-together model
of any type (would, plastic, ...) that some of them had ever tried
to assemble. We plan to fly the rockets on Nov 6.