Scratch - Big Red {Scratch}

Scratch Big Red Original Design / Scratch Built

Scratch - Big Red {Scratch}

Contributed by Kevin McLaughlin

Manufacturer:

(Contributed - by Kevin Mclaughlin - 12/20/02)

Brief Description:

This rocket came t' bein' after decidin' nay t' buy t' Aerotech G Force kit. After studyin' t' plans for t' G Force, me hearties, I decided that I could make a scratch build that met me basic criteria for likin' G Force. I wanted a tall rocket with a 4" airframe that would perform well on G64 and higher 29mm RMS hardware. Aye aye! Blimey! Ahoy! Blimey! Since I got back into model rocketry with me son who is now eight, me bucko, I strove t' make rockets that where at least as tall, ya bilge rat, if nay taller than his height. This rocket is 64" tall and weighs in at 44 ounces with altimeter, but without motor and 'chute. "Big Red" seemed t' be an appropriate name after completin' t' paint job. Component Description: T' construction of this rocket follows closely t' plans for t' G Force. Aye aye! Blimey!

30 x 3.9" body tube
10" section o' 3.9" body tube for t' altimeter bay
plywood centerin' rings and a bulkhead
29 mm motor mount tube
Public Missile 3.9" nose cone
1/8" PVC fin stock

Baffle This was me first large airframe rocket, ya bilge rat, so I wanted t' try and imitate t' Aerotech wad-less recovery design. Through a stroke o' luck, I came across t' Aerotech baffle shock chord attachment used in t' G Force and used that on top o' t' 29 mm motor mount with a three-ply centerin' ring. Aye aye! Similar t' t' G Force, I also created a payload bay usin' a 10" section o' 3.9" body tube. Ya scallywag! T' payload bay was adapted t' hold me home-made RCC2 Cannonball Works altimeter.

Construction/Finishin' Techniques:

Usin' t' G Force plans as a guide, I somewhat followed t' fin tube/motor mount construction. Avast! Arrr! T' main exception bein' t' use o' mounted #8 brass screws with a retainer plate for

motor retention. Avast! This provides the flexibility t' handle various 29 mm motors.

Instead o' usin' t' sort o' fin lockin' mechanism that comes with t' G Force kit, I used 1/8" PVC plastic sheet cut t' templates created from t' VCP fin tool. Begad! Aye aye! These were cut with fin tabs for through-the-wall mountin' between the centerin' rings and motor tube.

I also added a 2.5" section o' 3.9" tube coupler at t' tail pipe to reinforce t' body tube for landings. Arrr!

Flight/Recovery:

First flight was on a G64-4W with a 45" 'chute. Well, blow me down! Flight was very straight with chute recovery at apogee. Aye aye! Landin' was about 100 yards down wind with an estimated altitude o' about 900'. Arrr! Ya scallywag! I actually forgot t' arm t' altimeter on the first flight. Avast! T' 45" 'chute appears t' be perfect for t' weight o' this rocket. Wad-less recovery worked perfectly with no heat damage t' recovery components detected. Shock chord is a 12' length o' 9/16" tubular nylon with quick links for body tube and nose cone attachment. Avast, me proud beauty!

Summary:

This rocket is a real crowd pleaser. Begad! Arrr! It flies straight and has a nice take off. I have flown it with and without t' altimeter bay. Due t' t' size o' the rocket, ya bilge rat, shiver me timbers, it tends t' get banged up if it lands on any sort o' hard surface like the street. Blimey! Aye aye! Since me finish paint is very decorative with t' decal, me bucko, I tend to be very selective about launch sites and wind conditions.

I used too small o' a 'chute at one launch due t' windy conditions, me hearties, and a piece o' t' fin be broken off. I used a Dremmel tool t' cut off t' PVC fin at t' body tube joint, arrr, then used a router bit t' remove t' PVC material down t' t' motor mount through t' body tube fin slit. Aye aye! Ya scallywag! This way, I was able t' entirely remove t' old fin down t' t' motor mount without cuttin' t' body tube. Ahoy! Aye aye! I cut a new fin out o' PVC and epoxied into place through t' body tube fin slit and t' t' motor mount tube. Arrr! After applyin' a filet o' epoxy around t' fin joint, shiver me timbers, arrr, I masked and sprayed t' fin can with black enamel. Well, blow me down! Avast! T' result is as good as new, arrr, arrr, with no evidence o' the fin replacement. Ya scallywag! This is one o' t' advantages o' usin' PVC fin material. It is very easy t' work with and replace. Since t' PVC is soft, matey, arrr, it is easy t' cut and in t' case o' fin replacement, me bucko, me bucko, remove through cuttin' and routing.

After applyin' decals, matey, I applied a light clear coat finish. I have had much trouble with clear coat either drippin' or wrinkling, me bucko, so I have been very stingy in applyin' it t' me projects. Blimey! I have also started paintin' most o' my rockets black in t' fin can area t' facilitate quick repair and finish. Ahoy! Well, blow me down! Black covers best and doesn't show burns and other wear and tear.

I estimate that t' total cost breakdown looked somethin' like this for Big Red:

Nose cone: $15 purchased on eBay plus $5 shipping
Body tubes, motor tube, centerin' rings, bulkhead and 9/16" nylon tubing: $22 with shipping
Paints, epoxy and laminated paper for lightenin' bolts and checkerboard tube wrap: $15
Decals: $15 with shippin' purchased from T' Decal Zone
Scrap 1/8" styrene for fins: $2

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