Manufacturer: | Estes |
Style: | Futuristic/Exotic |
Brief:
Fiberglassed body and fins. 3mm Kevlar® shockcord. LOC precision 16"
parachute. Centering rings were glued using 5 minute epoxy. All joints were
glued using epoxy.
Modifications:
The Silver Comet is a great looking kit which I felt deserved to be built to
last and fly on E and F motors. To this end I decided to re-enforce the body
and fins (balsa) with fiberglass using West Systems Epoxy and my trusty food
saver to vacuum bag them both. Prior to laying up the fiberglass I had a some
wooden mandrels turned to keep the thin Estes body tube from being crushed by
the atmospheric pressure from the vacuum bagging process. The mandrels were
turned from cedar but any wood will do since all you want is to provide a solid
tube 'within a tube' to support your airframe during the fiberglassing and
vacuum bagging process. I used a 4oz fiberglass cloth since it is light yet
strong in a single covering. The resulting tube was still flexible but strong.
The fins that come with the kit are made from balsa so it was obvious these would have to be re-enforced. Again a single layer of fiberglass and vacuum bagging in a single process (i.e. each side of the fins had a single layer of fiberglass applied in the same session) yielded strong but pliant fins with only a small weight penalty (epoxy resin can really add weight so for something like this the vacuum bagging is a must).
I also noticed the usual elastic Estes shock cord provided. I don't like elastic as it eventually breaks. Instead I used 10' of 3mm tubular Kevlar® (Pratt Hobbies can sell you this) which I connected to the motor mount through the forward centering ring. The Kevlar® is glued down onto the motor mount and a knot tied to keep it from slipping back through the centering ring.
The 24mm motor mount is built with the supplied cardboard centering rings. I used 5 minute epoxy to provide a solid bond and give some stiffness to the cardboard. The result was a stiff motor mount assembly which was not overly heavy.
Finally, I replaced the usual Estes plastic parachute with a nice LOC Precision 16" pink nylon chute.
Construction:
Construction/Finishing PROS: Packaging is always good with Estes kits. The
instructions are always clear with lots of diagrams. All the parts arrived
undamaged including the very nice Silver Comet decals. Since this was a kit
bash I can't really say more about a 'stock' build. The CONs': Well the
modifications I have made are really in response to the CONS.
Flight:
A D12 is the recommended motor for this kit. However, due to my modifications
it was clear that a D12 would not provide enough thrust to get this off the
ground safely. Besides I wanted this to roar off the pad on an E or F. So,
after much simulation with ROCKSIM I decided on a maiden flight on an Aerotech
SU - E30-7. The casing had to be sanded down a bit to fit inside the Estes 24mm
motor tube. After a minute of sanding the motor fit nice and snug with the
D-clip fitting over the end perfectly. I have only flown this once but the
E30-7 pushed this 10oz rocket straight up to 1000 feet in a 15mph wind.
Deployment was visibly at apogee with the parachute opening immediately. A nice
soft landing was made about 1/4" mile down range. The rocket was recovered
without a scratch to the paint work. The next flight will probably be on an
F24-7.
Summary:
PRO: I have built my share of Estes kits and this and the V2 are my favorite. I
like the 2 1/5" body tube and finishing you can give to this size of
Rocket. CON: Well, Estes really must bite the bullet and replace the plastic
parachutes in this size of kit and then consider if elastic must go as well.
Other:
Always overbuild your rockets. The added weight can usually be compensated for
by using a larger motor and in the end you will get a rocket you can fly again
and again (though it will cost you more as well in propellant).
( Contributed - by Tristan Higbee ) The Silver Comet is a 1997 edition Estes model rocket. It is a skill level two and is one out of the few Estes rockets that takes a "D" engine. It is a fairly easy rocket to make if you have some experience. It requires a ¼ inch launch rod and is 25" long. The average cost of a Silver Comet is about $20, and I think it ...
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