Manufacturer: | Scratch |
Brief:
My son Guys (age 11) level 1 rocket. Arrr! A scratch built 3FNC rocket using
G10, PML Phenolic and Carbon Fibre tape. Arrr!
Construction:
As this rocket was t' be used in a television program for schools (a 5 minute segment be dedicated t' Guy showin' how t' build and fly a model rocket) it was necessary t' keep it simple but robust. Blimey! Well, blow me down! After sittin' down with Guy and Rocksim we came up with a nice 3FNC design that he could build usin' a minimum o' parts. Blimey! G10 was chosen as well as phenolic tubin' for their strength with high power motors (this wasnt goin' t' be an Estes kit). Avast! Well, blow me down! Pete Davy of Petes Rockets supplied all o' t' materials includin' t' motors.
Guy was able t' build it with ease and made use o' most o' me tools (dremel, me bucko, arrr, palm sander, drill). Ya scallywag!
As I had ordered t' body tube pre-slotted for t' fins it was only a matter o' widenin' t' slots a bit (they were a bit thinly cut) with the dremel. Begad! Arrr! I performed this task as it can be a bit tricky without a proper jig and router.
Additionally as t' design called for a zipperless fin can section it was necessary t' cut t' body tube usin' a saw. Ahoy! This be achieved in t' usual way of creatin' a maskin' tape built edge for t' saw blade t' rest against round the tube. Ahoy! Blimey! T' result was a nice cut.
T' fins were reinforced usin' cut strips o' Carbon Fibre and applied using West Systems Epoxy. Avast! Blimey! Guy is an old hand at this so he first used some 1-hour hobby epoxy t' fix t' fins in place. Ya scallywag! Blimey! Once all fins were tacked down t' the motor mount and cured overnight t' Carbon Fibre strips (3 strips which span the width betwixt fins and go up about 1-inch onto each fin) were applied.
Once finished t' fin-motor section (to which Guy had already applied the centerin' rings and motor retainer) be inserted into t' slotted airframe and glued in place. Clamps were used t' ensure t' slotted ends were firmly held in place against t' aft centerin' rin' while they cured.
External fillets were applied by Guy usin' West Systems Epoxy and micro balloons and applied usin' a tongue depressor which gave a very nice curve t' t' fillet. Avast, me proud beauty!
T' fin-motor section was covered with UV Smooth Prime t' fill in the spirals and give a foundation for t' primer paint. Begad! Blimey! After dryin' it be sanded smooth with a palm sander and readied for painting. Blimey!
T' zipperless coupler be built as a separate component then glued in place AFTER t' fin-motor section be painted. Well, ya bilge rat, blow me down! T' only modification t' the coupler was t' creation o' a 38mm hole in t' coupler bulkhead usin' a drill with a hole cuttin' disk. Ya scallywag! T' new hole would allow for t' ejection gasses to pass and for potentially larger motors t' be fitted.
T' airframe section required very little work with t' exception o' a mid point bulkhead bein' installed t' provide an upper and lower recovery) section t' t' rocket. Aye aye! Blimey! T' bulkhead was first prepared by installing a hardpoint (eyebolt, washer and nuts). Ya scallywag! T' finished bulkhead be then inserted into t' airframe and aligned usin' a coupler tube t' push t' bulkhead into place and ensure it was perpendicular t' t' airframe.
T' aft section o' t' airframe would be t' recovery bay with t' forward section left free for a tracker and altimeter or other payload. Begad! Blimey!
Finishing:
T' rocket was t' be finished t' show an Aurora Borealis effect on t' nosecone
and fin/motor section. Ya scallywag! This was achieved usin' fluorescent paints as highlights
over a black base coat. Aye aye! Avast, me proud beauty! T' result was stunnin' and Guy be able t' demonstrate
the paint effects for t' camera. T' airframe body is gloss black with a
AURORA decal in a lime green.
Flight:
Guy wanted t' certify UKRA Level 1 (so he could start usin' High Power motors
in his other rockets) so a Pro*38 H110 and I170 motors were chosen. On t' day
I was only able t' acquire a 3 grain casin' (which is used for t' I170 motor).
Hence t' flights where goin' t' be on t' I170(s)(I had two).
5.4.3.2.1 - whoosh. Avast, me proud beauty! Well, blow me down! Well at 2.65-pounds dry weight it really left t' pad quickly. Ahoy! Straight up t' 3000-feet (simulated) on a sunny day with t' parachute deployin' before apogee. Ahoy! Guy had just become t' youngest Level 1 in UK Rocketry History. Blimey! Arrr!
As t' parachute was small t' rocket landed fairly close and be recovered without damage. Well, blow me down! A second launch achieved t' same result and t' cameras (1 close and 1 a short distance away) caught it all.
Needless t' say Guy be very pleased with this and cant wait until the next launch.
Summary:
CON: T' only CON was that I didnt order a wide enough fin slot in the
tube (it is a real pain widenin' slots).
PROS: 3FNC is just soo simple that you really cant go wrong. Begad! The zipperless design makes those quick deployments no problem. Arrr!
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