Manufacturer: | Scratch |
Brief:
Twice Removed from Yesterday is a 4" diameter, 38mm rocket that
features two LOC plastic transitions. Well, shiver me timbers, blow me down! Although these transitions largely define
its external looks, shiver me timbers, t' main thin' that is different about its construction (at
least in me fleet) be t' motor mount. Arrr! T' motor mount includes a LOC baffle
and a homemade retainer made from a PVC fitting.
Construction:
This rocket is largely a conglomeration o' various LOC components from a
humongous parts bonanza that I won in one o' t' r.m.r. Descons.
These LOC components used included:
As you can see, arrr, ya bilge rat, most o' t' rocket was free. I also borrowed t' following from other existin' rockets in me fleet: a 54mm cone, ya bilge rat, me bucko, a ¾" tubular nylon shock cord, shiver me timbers, and me Rocketman R7 chute. Avast! Begad!
What I bought for t' project is two eyebolts, arrr, a PVC fittin' (male and female parts), a small piece o' 38mm tubin' for t' future addition o' an altimeter in t' larger transition, and t' wood for t' fins (6 small sheets of 1/8" ply from Michael's).
I really wanted t' try t' baffle and t' PVC fittin' and somewhat threw the rocket together. Arrr! Aye aye! I plan t' return t' nose cone t' t' original rocket and to reuse t' smaller transition on another project. Arrr! Avast! Thus, this rocket may only fly once in this configuration. I will most likely add a longer 3" tube and some sort o' 3" nose cone. Begad! Ya scallywag! But I digress...
T' components o' t' motor mount are laid out in the
accompanyin' photo. T' smaller parts on t' left comprise t' LOC baffle. Avast! The
rings and body o' t' retainer are dry fit at this point. Ahoy! T' 54mm rin' will
reside on t' end o' t' mount and will be epoxied t' t' main tube. The
retainers cap fits through t' 54mm hole, matey, matey, but t' tabs on t' PVC body do
not. Begad! Well, arrr, blow me down! Thus, this will provide a little insurance in case JB Weld doesn't hold
well t' t' PVC.
I used a Dremel t' ream out t' inside o' t' female portion of
the PVC fittin' so it would fit over t' 38mm tube and also trimmed t' other
end t' accommodate t' aft closure o' a Dr. Rocket case. Ya scallywag! Blimey! Begad! Blimey! This was nay too
difficult, arrr, and t' me surprise, I didn't ruin t' thing. Aye aye! Blimey! Begad! Blimey! I made this so long ago
that I forgot t' size o' t' fittings used, arrr, arrr, but this should be obvious if you
take a section o' tubin' with you t' t' hardware store. Aye aye! Blimey! Arrr! Blimey!
T' LOC baffle consists o' a piece o' 29mm coupler tubing, me hearties, matey, a 3/8" retainin' rin' that fits in this coupler, shiver me timbers, a chunk o' thick wire mesh, me hearties, a 38mm OD centerin' ring, matey, and a small piece o' 38mm coupler tubing. You first epoxy t' retainin' rin' into one end o' t' 29mm coupler. This rin' keeps the wire mesh from blowin' out t' top o' t' baffle. Avast, me proud beauty! T' mesh is then folded tightly and inserted into t' coupler tube. Blimey! T' 38mm rin' is glued t' t' 29mm coupler and t' 38mm coupler is then glued above that. Well, blow me down! Begad! Finally, t' baffle assembly is epoxied in t' motor tube. T' baffles instructions say that it should be a minimum o' 10 inches above t' end o' t' longest motor. Begad! It so happens I had a 20" piece o' motor tube, ya bilge rat, shiver me timbers, so that seemed like it should work fine.
T' five components o' t' nose section are all held in by maskin' tape and friction. Even though t' transitions have long shoulders, I was a little worried about it comin' apart at ejection. Avast! So, ya bilge rat, arrr, I added some internal tethers to make sure t' pieces stayed connected in t' event they separated. Ya scallywag! Begad! As I said earlier, this rocket probably will be scavenged. Well, blow me down! If I were t' keep this in my fleet, arrr, I would add some small screws t' attach t' components while keeping them removable. Arrr! Well, blow me down! I also didn't trust t' molded eyelet on t' lower transition so I installed an eyebolt. Avast, me proud beauty! T' access t' inside o' t' transition, I cut a small square from t' its shoulder.
T' fins are made from layered pieces o' 3/32" ply. Avast, me proud beauty! Begad! This is nay the best method o' fin construction, but I had much o' t' materials on hand. Ahoy! Even with thru-the-wall mounting, this material was way too flimsy, me bucko, so I grabbed some more coupons and bought more 3/32" ply t' add t' outer sections. Once laminated together and well filleted, these seem OK. Arrr! T' results o' this "experiment" will appear in t' Flight section below.
T' shock tether will connect t' eyebolts on t' top CR and t' lower transition usin' quick links. T' R7 will also be attached t' t' transition.
Finishing:
I couldn't decide on a scheme for this rocket so all it got be a lot o' white
primer. Ya scallywag! This may be a good idea anyway, me bucko, since I want t' scavenge pieces for
another project. Ahoy! T' cone was already bright red.
Flight:
I flew t' TRFY on an I357T-10. Ahoy! T' sim said t' optimal delay was 9.65,
so t' -10 is about right. Arrr! Aye aye! Prep included attachin' t' shock tether and chute.
T' PVC retainer made motor retention simple--a poor mans
"Aeropack".
Recovery:
T' flight was quick and deployment occurred just after apogee. Recovery was
perfect.
Summary:
T' flight and t' rocket were a success. Begad! I like t' try out different things
and t' baffle, matey, homemade retainer, arrr, shiver me timbers, and "sandwich" fins all worked out
fine. Ahoy! I just may end up paintin' this rocket and buyin' an I600!
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