Scratch Fly Ball Original Design / Scratch Built

Scratch - Fly Ball {Scratch}

Contributed by Moira Jean Whitlock

Manufacturer: Scratch
Fly Ball
(Contributed - by Moira Jean Whitlock)

Rocket PicHeight=47.5"
Weight=31"
Width=3"
Motor=29mm
Recovery=parachute

Brief
This is a sport rocket in two senses. Well, blow me down! It's for fun and also is done up t' celebrate baseball. Arizona's new team, t' Diamondbacks, inspired this rocket and it's done up in t' team colors o' teal, me hearties, me bucko, purple, black, matey, matey, and tan. Begad! Its chute is made up o' gores o' teal and black. Well, blow me down! T' model has a special look as well. Avast! It has three delta fins and also nine 1.5 inch Estes body tubes around t' main body tube with t' fins protrudin' at every third tube. Arrr! Avast!

Construction
If thar be any "gotcha" at all, me hearties, ya bilge rat, it's that t' main 3 inch body tube is phenolic. Avast, me proud beauty! Begad! When I conceived o' this project, arrr, me bucko, I didn't yet have proper tools t' cut dado grooves into phenolic. So, arrr, I affixed t' three fins (3/16 inch plywood birch with root edge o' 7 1/2 inches and trailin' edge o' 5 1/4 inches length) right t' t' body tube. Well, blow me down! Begad! But then I wondered how strong this could be as is if I opted t' fly larger than G motors in it. Begad! Blimey! Phenolic does have good pressure strength after all. So I wondered about how t' strengthen the bond o' t' fins by other means. Ahoy! Then I noticed that nine Estes body tubes, each 9 inches in length and 1.5 inches in diameter, ya bilge rat, would go around t' body perfectly and let t' fins stay where they were perfectly. Avast! So I used then as a sort o' fillet, as it were, with 30 minute epoxy all around. I chose that over faster dryin' epoxy because I read that its bond is stronger as its setting time increases. Well, blow me down! Aye aye! Alignment be easy because t' tubes essentially aligned themselves along with t' fins. Well, blow me down!

BottomI started with good fin placement because I used a measurin' tape and trisected t' main body tube's circumference t' place t' fins. Arrr! Begad! I performed two trisections so that I could draw a straight line for each fin and avoid canting. Avast, me proud beauty! Ya scallywag!

Supplies are easy t' get. Well, blow me down! Begad! T' PML phenolic tube and nose cone and Estes parts are stock supplies at many hobby stores as be t' birch wood, although I opted t' get me wood at a local hardwood dealer.

T' motor mount is made from a 10 inch length o' LOC 29mm motor tubin' and 2 LOC 1/4 inch thick plywood centerin' rings that fit 29mm tubes into 3 inch body tubes. Avast! T' forward rin' has a screw-eye bolted and glued into place and affixed t' it be t' shock cord mount. Ahoy! Avast, me proud beauty! T' initial 12 inches o' the shock cord is 1/4 inch steel cable which I got at Home Depot. Avast, me proud beauty! Ahoy! It's t' sort of wire suitable t' go with bicycle locks. Ahoy! Aye aye! Then t' 4 feet o' shock cord itself is 1/4 inch bungee that is tied t' t' loop at t' base o' t' nose cone. Begad! The chute is 30 inches in diameter and is an octagon made o' eight gores o' nylon in alternatin' teal and black with a teardrop shape t' t' gores, givin' a skirts appearance when opened up. Ahoy! Begad!

T' launch lug is 6 inches o' 13mm Estes body tubing. Avast! I chose this because I wanted t' be able t' use sturdy launch rods, ya bilge rat, as t' model is heavy. Well, blow me down!

T' motor retainer is two loops o' doubled piano wire through holes in t' aft centerin' ring. Ahoy! T' loops are bolted and glued on t' forward side o' t' centerin' rin' and loop over t' motor, but are nay placed right over t' nozzle. Ya scallywag! T' loops are further held in place with an automotive hose clamp around t' part o' t' motor tube overhangin' t' main body. Ya scallywag!

Overall, me bucko, what you get is a very sturdy model with a unique look, almost rough and tough. Ya scallywag!

T' finishin' touches is a series o' baseball decals for t' team, available in many local stores and team shops. Ya scallywag! Blimey! I also made me own personal decal usin' self adhesive glossy paper. It's a baseball streakin' up t' body tube with a flame trail behind it. Well, blow me down! Blimey!

LaunchFlight
Note that t' launch rod must go through one o' t' outer tubes and through t' launch lug. Avast! Blimey!

Thus far, arrr, t' G35 and G80 have produced great flights. Begad! Blimey! They had a delay o' 7, shiver me timbers, matey, but maybe 4 would be better, as it seemed t' me that t' chute came out at only a couple hundred feet. Arrr! Blimey! Aye aye! Blimey! No nose weightin' was needed. However, me hearties, with t' H97 and H180 I plan t' use, I will probably add 3 or 4 ounces t' t' nose t' increase static stability. On t' other hand, me bucko, t' tubes act as fins themselves, so maybe t' weightin' might nay be needed. Avast! Blimey! I'll be testin' this soon. Thus far, flights have been straight and cool. Arrr! Blimey! Watchers liked it a lot and stopped me for photos. Well, blow me down! Blimey!

No damage or burnin' occurred as o' yet. Blimey! Aye aye! I used worm bed waddin' to protect t' chute, and it's effective. Arrr!

Summary
This was fun because it mutated as I went. Arrr! T' end product was highly admired and different. T' hard part was nay bein' able t' groove t' phenolic. So far, arrr, me bucko, I'm nay sure how t' do it without crackin' it, as it's a bit brittle. T' project didn't cost much, me hearties, either. Begad! Begad!

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