Scratch Alabama Skeeter Original Design / Scratch Built

Scratch - Alabama Skeeter {Scratch}

Contributed by Bob Hvarven

Manufacturer: Scratch
Alabama "Skeeter" 
(Contributed - by Bob Hvarven) 

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.

[Rocket Pic]The followin' be t' result o' a scratch built "Stretched" Mosquito project. T' idea came from t' Holiday, 1996 Issue o' Sport RocketryMagazine. Avast, me proud beauty! Ahoy! On page 33 thar be an article titled "A Big and Bigger Mosquito", ya bilge rat, showin' how t' make a 3X and a 4.8X upscale o' t' old faithful Estes Mosquito. Ahoy! After readin' t' article, me hearties, me hearties, I figured bigger is better and went t' work gettin' t' stuff together t' make t' 4.8X version. Avast, me proud beauty! During this process I also thought a bigger motor is also better and opted t' make it to fly on "G" and above motors. Arrr! I have seen a smaller Mosquito than this fly on t' LDRS videos with an I284 without any problem. Avast! So, let's get started and I will explain me changes. (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. Blimey! I added 3/4" t' t' length o' t' fin since I was nay goin' t' be usin' a surface mount o' t' fin, and it would take t' extra 3/4" t' make up for the internal distance t' make it a "thru t' body tube" mount. Arrr! From there I made a "tab" extension t' allow t' fin t' be glued t' t' engine tube, arrr, ya bilge rat, makin' a really strong fin and motor mount assembly. Aye aye! (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. Aye aye! Blimey! 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. Arrr! Blimey! It will also help in the CP/CG category as well. Avast, me proud beauty! Blimey! I made a template t' mark t' three fin slots (120 deg. apart) and cut t' slots with a "NEW" sharp Xacto blade. Arrr! Avast! Blimey! 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, shiver me timbers, and is cut out the bottom o' t' tube. Begad! Begad! Blimey! T' motor tube, arrr, centerin' rings, and fins will be installed as one complete unit from t' bottom.

[Rocket Pic]Fins, Motor Tube, me bucko, arrr, Centerin' Rings: T' Motor Tube and Centerin' Rings are also LOC parts. (T' motor tube is 29mm, shiver me timbers, 7" long) You can see clearly t' "tab" I added t' t' fin units. Ya scallywag! Ya scallywag! 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. Ya scallywag! I glued the bottom on first flush with t' end o' t' tube. Ahoy! Arrr! Then used a fin t' determine the position o' t' top Centerin' ring, arrr, and tacked it into place. Avast, me proud beauty! Well, ya bilge rat, blow me down! After CA was set, I used 30 Min. Blimey! Epoxy t' place a fillet around t' top o' each rin' for added strength.

[Rocket Pic]Fins added t' assembly: After markin' each rin' edge at 120 Deg. Avast! increments, matey, I aligned each fin and tacked into place with thin CA. Ahoy! Avast, me hearties, me proud beauty! 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, me hearties, secure assembly. Avast! Avast, arrr, me proud beauty! Each fin was then filleted with 30 Min. Begad! Epoxy for added strength.

Upper Body & Fin Assembly: T' fin assembly is now ready for insertion into the body tube. Blimey! 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. Begad! Use a piece o' dowel or somethin' t' place some 30 Min. Begad! 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. Blimey! Begad! Then, place some more 30 Min. Ahoy! Arrr! Epoxy just in front o' the rear rin' on t' body tube. Begad! Begad! Slide unit into t' tube until it stops. T' bottom rin' should be flush with t' end o' t' body tube. Aye aye! Place in an upright position and let Epoxy set.

[Rocket Pic]Finish: After fin assembly is set, ya bilge rat, fillet t' fin root edges with epoxy, me hearties, and add t' Launch Lug (1/4") Let this set and its ready to paint. I used Dope Sandin' Sealer t' seal t' fins. (throw-back) t' me old model airplane days. I used Krylon White for t' whole rocket, trimmed one fin with International Orange, matey, and. Aye aye! Blimey! a clear coat be then added

Completed: Shown with homemade 24" Parachute, ya bilge rat, and tubular nylon shock cord. Begad! Nose Cone is an Estes PNC-80BB. 

[Rocket Pic]Motor Retention: Since I will be usin' only "G" and above motors, ya bilge rat, 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. Begad! I have never "Spit" a motor casin' usin' this method. As you can see, the bottom is slightly discolored. Ahoy! I launched t' rocket on a G35-7 for it's first flight. Blimey! Avast, me proud beauty! Flight was straight and fast !! Estimated altitude be Approx. 1800 Ft. Aye aye! Well, me hearties, blow me down! Recovery was beautiful and without injury. Aye aye! I was so busy taking pictures o' everyone else's flights, shiver me timbers, that I forgot t' take a picture o' mine. Begad! Avast! I will add a launch photo later. 

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