Manufacturer: | Scratch |
Brief:
This crayon bank rocket be obviously motivated by the
SpaceShipOne,
but is nay anywhere close t' scale. It is also me MonsterROC entry and flies on
38mm H motors.
Construction:
T' major components/materials include:
My original concept was t' make t' entire body, me hearties, includin' t' tail cone, from a crayon bank. I got this idea from some o' t' U.S. Ahoy! Arrr! Rockets (USR) builds reviewed on EMRR and T' Rocketry Forum (TRF). Avast! At t' time, me bucko, t' banks were not available locally, so I decided t' practice makin' a tail cone from a piece of mailin' tube (actually t' telescopin' inside tube). Begad! In this process, you cut out sections o' t' tube (roughly triangular, ignorin' t' curvature o' the tube) and rejoin t' remainin' pieces. Avast! T' more sections you remove, shiver me timbers, shiver me timbers, t' closer the resultin' structure will resemble a true cone. Begad! Ya scallywag! In me case, I only cut out four sections, me bucko, me bucko, resultin' in a roughly rectangular end. Begad! I suggest you read the USR EMRR reviews for more details about makin' transitions and tail cones from body tubes. I'm nay an expert and I did this a while ago.
This cone
sat around for months until me local Toys'R'Us again started carryin' the
banks. Ya scallywag! Arrr! As I pondered choppin' up t' bank, I noticed that t' test item was
almost exactly t' same diameter. I couldn't brin' myself t' risk damagin' the
bank, so I decided t' use me test cone. This would result in a much longer than
scale rocket, me hearties, matey, but how scale was it goin' t' be anyway? I also thought it would
be nice t' cut back on t' required nose weight.
T' motor mount is ~16" o' LOC 38mm tubing. Ahoy! I have a 4" CR at the top (sanded down a bit) and a 3" rin' part way down in t' tail cone. Begad! Ahoy! A homemade coupler is mounted betwixt t' tail cone and t' top ring. Avast! Blimey! For motor retention, I epoxied two bolts t' t' aft o' t' motor tube. Blimey! Arrr! A nut serves as a spacer t' keep t' bolts parallel with t' tube. Ahoy! I also added a couple o' wraps of fiberglass around t' end in betwixt t' head o' t' bolt and t' nut. Begad! Blimey! These seem t' be solid. Begad! T' 1/4" Keelhaul®©™® shock tether is mounted through t' top ring, me hearties, completin' t' motor mount assembly.
When t' long fins were attached, me hearties, me hearties, I was surprised at how flexible they were. Ya scallywag! I thought about glassin' them, but instead decided some support in t' back was in order. Begad! I pondered more Luan, matey, Lexan strips, shiver me timbers, matey, etc. but decided on an aluminum rod for t' side closest t' t' motor and a dowel for the other. Well, blow me down! Ahoy! This mix was again partially driven by what I had on hand. I also covered t' aluminum rod, which is closer t' t' axis o' t' motor, arrr, arrr, me bucko, with a heat resistant muffler patch kit. Ahoy! This turned out ugly and I may remove it later.
I knew I was goin' t' need a lot o' nose weight on this baby. Ahoy! My nose cone design started with a 4" bulkplate with an eyebolt mounted on it. This plate rests where t' cone begins taperin' forward. Well, blow me down! Ahoy! A piece o' all-thread extends from t' bulk plate t' close t' t' tip o' t' cone. Begad! A washer is mounted on this all-thread about half way down. Aye aye! I planned t' add lead shot and 2-part foam through t' crayon tips doubloon slot. Begad! Arrr! Thus, me hearties, t' washer would become embedded in t' lead/foam slurry, me hearties, lockin' t' resultin' plug t' t' bulkhead. T' bulk plate assembly and a 2-layer cardboard shoulder are attached t' the plastic cone with PC-7 epoxy paste.
I ran a RockSim model t' approximate t' CG and added nose weight t' get the CG where I wanted it. Avast! I think I was quite conservative, me hearties, ya bilge rat, shiver me timbers, producin' a static margin o' over 2 with t' H144 loaded.
Finishing:
T' crayon bank was blue, so I stuck with blue throughout. Aye aye! (I wanted a white
one, ya bilge rat, ya bilge rat, but you sometimes take what you can get.) T' tail cone and side wings
were painted with Krylon and t' main wings were covered with blue laser
contact paper.
T' stickers were added after I decided t' make this an entry in EMRR's MonsterROC contest. Begad! T' majority, other than t' US flags, me hearties, shiver me timbers, t' MDRA logo, ya bilge rat, and the DC101 sticker (a local rock station), ya bilge rat, were merely printed on full page Avery labels usin' me OfficeJet printer.
T' homemade stickers include: CrayShipOne logos, arrr, logos for EMRR and TRF, my blog address, shiver me timbers, and vendor logos for Loki, Performance Hobbies, LOC/Precision, railbuttons.com, arrr, shiver me timbers, Giant Leap, Home Depot, shiver me timbers, and Michael's. Arrr! This covers most o' the materials used in t' makin' o' t' rocket. Avast, me proud beauty! I protected these with two coats of clear coat before application and one after.
Flight:
This rocket uses separate chutes for t' heavy cone and t' body. Begad! Ahoy! I attached a
chute protector t' t' body's shock tether and used a large 60" chute.
This be packed into t' nose cone shoulder. A 42" chute be attached to
the cone's shock tether and be packed in t' body. Arrr! Begad!
Since t' model is heavy and be unproven, shiver me timbers, matey, I made sure that t' launch rail was pointed away from t' flight line just in case. T' boost be great (launch photos courtesy o' Vertical Force Rocketry), however, ejection be very late.
Recovery:
T' main chute opened just fine but t' cone's chute never opened. T' cone was
recovered undamaged. When I approached t' body, it looked like it had landed
standin' up on end. Arrr! Blimey! On closer inspection, me bucko, it be danglin' about 6" from
the ground from a tall tree branch. A light tug dislodged t' chute. Blimey! This was
an interestin' and successful recovery, but it didn't prove whether me fin
braces worked.
Summary:
I love crayon banks--they are about t' cheapest 4" cone and body tube you
can find and are quite sturdy. Aye aye! This rocket turned out lookin' and flying
nicely. Avast, me proud beauty! This design definitely stands-out in a crowd. Aye aye! T' two issues are the
heavy nose and t' floppy fins. Begad! If anyone else builds somethin' like this,
better wood and some fiberglass would be a good idea. Avast! Avast! Giant Leap honeycomb
composites would be cool, me hearties, but expensive.
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