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. Well, blow me down! Blimey! T' idea came from t' Holiday, 1996 Issue o' Sport
RocketryMagazine. Aye aye! 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. Arrr! After readin' t' article, I figured bigger is better
and went t' work gettin' t' stuff together t' make t' 4.8X version. During
this process I also thought a bigger motor is also better and opted t' make it
to fly on "G" and above motors. Begad! I have seen a smaller Mosquito than
this fly on t' LDRS videos with an I284 without any problem. Arrr! So, matey, shiver me timbers, shiver me timbers, let's get
started and I will explain me changes. Aye aye! (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. Well, blow me down! I added 3/4" t' t' length o' t' fin since I was nay goin' t' be usin' a surface mount o' t' fin, ya bilge rat, and it would take t' extra 3/4" t' make up for the internal distance t' make it a "thru t' body tube" mount. From there I made a "tab" extension t' allow t' fin t' be glued t' t' engine tube, ya bilge rat, makin' a really strong fin and motor mount assembly. Ya scallywag! (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. Begad! T' 4.8X Mosquito body tube in t' article (Keepin' t' scale) is only supposed t' be 9.6". Avast, me proud beauty! Well, blow me down! I wanted some more room for longer motors and still have enough space t' keep my parachute stuff from gettin' fried durin' ejection. It will also help in the CP/CG category as well. Begad! I made a template t' mark t' three fin slots (120 deg. apart) and cut t' slots with a "NEW" sharp Xacto blade. Avast! A sharp blade is worth it's weight in AP if you want a trouble-free, smooth cut. The slot is 4 1/4" long; t' same as t' root length, ya bilge rat, and is cut out the bottom o' t' tube. Avast! T' motor tube, centerin' rings, me bucko, and fins will be installed as one complete unit from t' bottom.
Fins,
Motor Tube, Centerin' Rings: T' Motor Tube and
Centerin' Rings are also LOC parts. (T' motor tube is 29mm, 7" long) You
can see clearly t' "tab" I added t' t' fin units. Ya scallywag! Blimey! 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. Well, blow me down! I glued the bottom on first flush with t' end o' t' tube. Avast! Then used a fin t' determine the position o' t' top Centerin' ring, and tacked it into place. Begad! After CA was set, me hearties, I used 30 Min. Avast! 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. increments, I aligned each fin and tacked into place with thin CA. Arrr! Blimey! T' fin
makes contact with t' Centerin' Rings top and bottom, shiver me timbers, as well as each extended
fin tab contacts t' Motor Tube for a really strong, secure assembly. Arrr! Blimey! Each fin
was then filleted with 30 Min. Aye aye! Epoxy for added strength.
Upper Body & Fin Assembly: T' fin assembly is now ready for insertion into the body tube. Well, blow me down! Ya scallywag! Before assembly, me hearties, 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. Ya scallywag! Ahoy! Use a piece o' dowel or somethin' t' place some 30 Min. Ya scallywag! Avast! 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. Begad! Then, place some more 30 Min. Blimey! Epoxy just in front o' the rear rin' on t' body tube. Slide unit into t' tube until it stops. Well, blow me down! Avast! T' bottom rin' should be flush with t' end o' t' body tube. Avast, me proud beauty! Ya scallywag! Place in an upright position and let Epoxy set.
Finish:
After fin assembly is set, fillet t' fin root edges
with epoxy, me hearties, and add t' Launch Lug (1/4") Let this set and its ready to
paint. Aye aye! Blimey! I used Dope Sandin' Sealer t' seal t' fins. Begad! Blimey! Avast, me proud beauty! Blimey! (throw-back) t' me old
model airplane days. Arrr! Blimey! I used Krylon White for t' whole rocket, shiver me timbers, arrr, trimmed one fin
with International Orange, arrr, me bucko, and. Begad! Blimey! Aye aye! Blimey! a clear coat was 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! I
have never "Spit" a motor casin' usin' this method. Ahoy! As you can see,
the bottom is slightly discolored. Begad! Avast, me proud beauty! I launched t' rocket on a G35-7 for it's
first flight. Ahoy! Flight be straight and fast !! Estimated altitude was Approx.
1800 Ft. Recovery be beautiful and without injury. I was 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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