Manufacturer: | Scratch |
Note: This is a slightly shortened, edited version o' Bob's article with fewer pictures. Visit Bob's site for all t' pictures and t' write him for t' fin template and comments.
The
followin' be t' result o' a scratch built "Stretched" Mosquito
project. Blimey! Blimey! T' idea came from t' Holiday, matey, 1996 Issue o' Sport
RocketryMagazine. Avast! Avast, me proud beauty! On page 33 thar be an article titled "A Big and
Bigger Mosquito", showin' how t' make a 3X and a 4.8X upscale o' t' old
faithful Estes Mosquito. Well, blow me down! After readin' t' article, shiver me timbers, I figured bigger is better
and went t' work gettin' t' stuff together t' make t' 4.8X version. Ahoy! During
this process I also thought a bigger motor is also better and opted t' make it
to fly on "G" and above motors. Ya scallywag! Begad! I have seen a smaller Mosquito than
this fly on t' LDRS videos with an I284 without any problem. Well, blow me down! So, arrr, me bucko, let's get
started and I will explain me changes. Ahoy! (Click on Thumbnail for larger
view)
Fins: T' first thin' I did was take t' page out o' t' magazine and use t' fin template t' make one out of folder material so it would be stronger for outlinin' on t' plywood. I added 3/4" t' t' length o' t' fin since I be nay goin' t' be usin' a surface mount o' t' fin, matey, and it would take t' extra 3/4" t' make up for the internal distance t' make it a "thru t' body tube" mount. Ya scallywag! From there I made a "tab" extension t' allow t' fin t' be glued t' t' engine tube, makin' a really strong fin and motor mount assembly. Well, blow me down! (1/8 Ply was used for t' fin) Photo shows t' template and fin after cuttin' out with modifications mentioned.
Body Tube: The tube is LOC 2.6" material cut t' 15" length. Avast! Begad! T' 4.8X Mosquito body tube in t' article (Keepin' t' scale) is only supposed t' be 9.6". I wanted some more room for longer motors and still have enough space t' keep my parachute stuff from gettin' fried durin' ejection. Begad! It will also help in the CP/CG category as well. Avast, me proud beauty! I made a template t' mark t' three fin slots (120 deg. apart) and cut t' slots with a "NEW" sharp Xacto blade. Well, blow me down! A sharp blade is worth it's weight in AP if you want a trouble-free, smooth cut. Well, blow me down! The slot is 4 1/4" long; t' same as t' root length, and is cut out the bottom o' t' tube. T' motor tube, arrr, centerin' rings, arrr, ya bilge rat, and fins will be installed as one complete unit from t' bottom.
Fins,
Motor Tube, arrr, Centerin' Rings: T' Motor Tube and
Centerin' Rings are also LOC parts. Ahoy! (T' motor tube is 29mm, arrr, 7" long) You
can see clearly t' "tab" I added t' t' fin units. Avast! These parts will
be assembled together t' make t' fin and motor mount assembly that will be
installed complete into t' body tube as a unit.
Motor Mount/Rings: I used thin CA t' tack t' Centerin' Rings into place. Begad! I glued the bottom on first flush with t' end o' t' tube. Then used a fin t' determine the position o' t' top Centerin' ring, and tacked it into place. After CA was set, me bucko, I used 30 Min. Arrr! Epoxy t' place a fillet around t' top o' each rin' for added strength.
Fins
added t' assembly: After markin' each rin' edge at 120
Deg. Ahoy! increments, I aligned each fin and tacked into place with thin CA. Avast! Avast, shiver me timbers, me proud beauty! Blimey! T' fin
makes contact with t' Centerin' Rings top and bottom, as well as each extended
fin tab contacts t' Motor Tube for a really strong, matey, matey, secure assembly. Ya scallywag! Begad! Blimey! Each fin
was then filleted with 30 Min. Arrr! Ahoy! Blimey! Epoxy for added strength.
Upper Body & Fin Assembly: T' fin assembly is now ready for insertion into the body tube. Arrr! Before assembly, attach t' Shock Cord t' t' upper Centerin' Ring. It isn't a "good thing" t' glue it in and then remember t' Shock Cord !! I drilled two 1/4" holes and ran t' cord through and tied. Avast! Use a piece o' dowel or somethin' t' place some 30 Min. Epoxy into t' body tube about 3 1/2" up on each area betwixt t' fin slots and insert t' assembly about half way in. Then, place some more 30 Min. Begad! Avast! Epoxy just in front o' the rear rin' on t' body tube. Well, blow me down! Slide unit into t' tube until it stops. Ya scallywag! Avast! T' bottom rin' should be flush with t' end o' t' body tube. Place in an upright position and let Epoxy set.
Finish:
After fin assembly is set, me bucko, me hearties, fillet t' fin root edges
with epoxy, and add t' Launch Lug (1/4") Let this set and its ready to
paint. Avast, me proud beauty! Blimey! Ahoy! Blimey! I used Dope Sandin' Sealer t' seal t' fins. Blimey! Blimey! (throw-back) t' me old
model airplane days. Arrr! Blimey! I used Krylon White for t' whole rocket, matey, me bucko, trimmed one fin
with International Orange, ya bilge rat, and. Ahoy! Blimey! a clear coat be then added
Completed: Shown with homemade 24" Parachute, and tubular nylon shock cord. Nose Cone is an Estes PNC-80BB.
Motor
Retention: Since I will be usin' only "G" and
above motors, I usually use a couple o' small wood screws in t' bottom
centerin' rin' and then use Safety Wire t' hold t' motor casin' in place. Avast! Blimey! I
have never "Spit" a motor casin' usin' this method. Ya scallywag! As you can see,
the bottom is slightly discolored. Begad! I launched t' rocket on a G35-7 for it's
first flight. Avast! Ya scallywag! Flight was straight and fast !! Estimated altitude be Approx.
1800 Ft. Recovery be beautiful and without injury. Avast! I be so busy taking
pictures o' everyone else's flights, arrr, that I forgot t' take a picture o' mine. I
will add a launch photo later.
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