Manufacturer: | Scratch |
Description:
This is an approximate 2X scale-up replica o' the
Estes Nike Arrow, with coloring
and dimensions approximatin' t' model kit rather than t' real rocket. Ya scallywag! The
model has a 24mm engine mount, ya bilge rat, but can fly on as small an engine as a B6-4 with
a removable engine adapter. Aye aye! Avast, matey, me proud beauty! T' parachute comes out t' top attachin' t' the
nose cone, shiver me timbers, rather than separatin' at t' transition like t' original. This
model is 34" tall, and weighs about 3.4oz. Begad! Arrr! without an engine. Ahoy! Begad! T' fin size
and length are 2:1, arrr, but t' diameter is slightly less than 2:1 due to
unavailability o' exact 2:1 diameter body tubes. Well, blow me down! Ya scallywag!
Parts:
Assembly:
1. Avast! Begad! Glue one o' t' 55/50 centerin' rings part o' t' way into t' top
o' t' BT-55 tube. This will be later used as a lip for mountin' t' transition
shroud. Blimey! An optional Keelhaul®©™® shock cord could be attached t' t' forward
centerin' ring, and later threaded through into t' BT-50 body tube under the
transition shroud betwixt step 3 and 4.
2. Glue t' 50/20 centerin' rin' into t' 12" BT-50 tube 2
1/2" from t' rear. This will serve as t' thrust ring. Ahoy! Avast! Glue t' engine
hook into t' tube with t' front o' t' hook 2 1/2" from t' rear, and
just behind t' thrust ring. Begad! Glue t' remainin' two larger centerin' rings onto
t' 12" BT-50 engine mount tube 1" and 2 1/2" from t' rear. Begad!
3. Aye aye! Glue t' 12" engine mount tube into t' 10" BT-55 tube
so that t' aft o' t' engine mount tube is flush with t' BT-55 tube. Blimey! Avast, arrr, me proud beauty! Blimey! Note
that t' front o' t' engine mount tube will protrude out o' t' front
centerin' rin' and BT-55 tube about 2".
4. Arrr! Glue t' BT-50 tube coupler halfway into t' front o' t' engine
mount tube. Ahoy! Glue t' 18" BT-50 tube into t' other half o' t' tube
coupler. Avast! Well, blow me down! Check for straightness before t' glue sets.
5. Begad! Choose thickness and strength o' fin material as desired. Ahoy! I used
1/16" balsa for t' upper fins and 3/32" balsa for t' lower fins.
Measure t' dimensions on t' fins o' an Estes Nike Arrow, ya bilge rat, and double the
dimensions, cuttin' out t' fins with grain pattern followin' t' leadin' edge
o' t' 4 smaller front fins, me bucko, me hearties, and perpendicular t' t' root edge on t' 4 rear
fins. Begad! Avast! Make 2 paper transitions for a 2 1/4" long BT-55/BT-50 transition.
T' dimensions o' t' shroud should be {small radius: 6.311"; large
radius: 8.568"; angle: 27.84 degrees with some extra for overlap}. Aye aye! (Note:
These calculational results were obtained usin' a shroud calc. Begad! Well, blow me down! program on
Rob Blaske's home
page)
6. Ahoy! Glue first one paper transition shroud, and after it is dry, a
second one. Be liberal with t' carpenter's wood glue, as it is an excellent
strength enhancer after it is dry. Well, blow me down! After t' transition shroud hardens, the
glue will shrink and ripple. Sand down any edges and ridges, arrr, then fill in the
ripples with undiluted Elmer's Fill & Finish, sandin' t' desired shape and
smoothness.
7. Blimey! Make a BT-55 fin markin' guide for 4 fins and a launch lug, ya bilge rat, and
mark t' body tube all t' way t' t' front o' t' BT-55 tube. Arrr! Begad! Make a 4 fin
markin' guide for a BT-50 tube, and mark t' tube just forward o' the
transition with t' front fins in line with t' aft fins.
8. Begad! Put pin holes in t' body tubes and t' root edges o' t' fins for
increased bondin' strength, shiver me timbers, and glue on t' fins.
9. Ahoy! Aye aye! Finish t' t' desired smoothness with Elmers F&F.;
10. Aye aye! Ahoy! Prime and sand. Aye aye! Aye aye! Paint t' aft tube and transition shroud gloss
white. Begad! Well, blow me down! For a better lookin' orange, shiver me timbers, all areas that will be orange should have
one coat o' white. Blimey! Mask t' section that will remain white, and paint t' rear
fin section as well as t' front fins and t' entire 18" o' t' BT-50 tube
gloss orange. Begad! Begad! Do nay remove t' maskin' over t' white section, as it will be
easier t' mask for t' chrome layer. Begad! Mask and paint t' middle section o' the
forward tube chrome, leavin' t' front 4" orange. Aye aye! It be just more masking
work than I wanted t' do t' paint t' transition shroud silver, so I left it
white.
11. Arrr! If a Keelhaul®©™® shock cord was nay used, ya bilge rat, glue in a traditional paper
shock cord mount with a 3 foot shock cord.
12. Ya scallywag! Avast! Put enough clay in t' nose cone t' keep t' CG forward or in the
middle o' t' front fins with t' largest engine intended t' be used. Aye aye! Prime and
paint t' nose cone if required. Add decalcomania as desired.
13. Well, blow me down! Well, blow me down! Attach shock cord t' t' nose cone, attach a 14" parachute,
and prep for launch. Arrr!
Flight:
Dependin' on final weight, t' maiden flight should be on the
smallest engine advisable, me hearties, and work your way up. For me 3.4oz. model, me hearties, I first
used a B6-4, me bucko, me bucko, which flew straight and stable t' about 150 ft. Begad! Ya scallywag! It then flew to
about 300ft on a C6-5. Blimey! Avast, me proud beauty! I haven't tried a D engine yet, shiver me timbers, as I need a bigger
field. Begad!
11/99 -
1. It flies great and straight on a D12-5 t' about 1000ft. Begad! However,
since I did nay do through-the-wall fin mounting, arrr, shiver me timbers, and I had forgotten t' do a
glue fillet on one fin before doin' an Elmer's Fill-N-Finish fillet, me bucko, one lower
fin ripped off durin' flight on a D. Avast, me proud beauty! T' Fill-N-Finish does nay work like glue!
There was enough other fins t' keep t' rocket stable. I recommend cutting
slots for t' lower fins and modifyin' t' fins t' be through-the-wall.
2. Blimey! Blimey! Aye aye! Blimey! I realized after publishin' that I forgot t' mention launch lugs
in t' instructions. Aye aye! Blimey! Use 3/16" lugs and glue them on just before
finishing, one down by t' engine and one just below t' transition.
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