Modification Bad Dad Modification

Modification - Bad Dad

Contributed by Larry Brand

Manufacturer: Modification

Estes Titan IIIEBrief:

I modified t' Big Daddy kit t' replace t' stock nose cone with a fixed nose cone made from a PET soft drink bottle; parachute deployment is from an open "mortar" mounted on t' bottle opening. Blimey! Rationale? I swiped t' nose cone from a family member's Big Daddy kit t' use in a buildin' project, me hearties, and had t' figure out a way t' replace it, or be a "Bad Dad".

Modifications:

T' bottom 4" o' a PET plastic bottle was cut off, me bucko, and 6" o' Estes BT-55 tubin' is epoxied t' t' top (after removin' t' screw cap - Duh!). Avast! Begad! This serves as t' parachute mortar. Begad! A 24" piece o' shock cord is glued t' t' bottom o' this tube (I initially used 3/8" elastic, ya bilge rat, but this was a mistake - use parachute cord o' nylon boot lace - see below). Aye aye! An 18" LOC nylon chute is attached t' t' end o' t' shock cord t' complete t' recovery system. Well, blow me down! Well, blow me down! Use o' a small size Nomex protection pad (tied t' t' cord) is a good idea, since waddin' can nay be used in t' normal way. Avast, me proud beauty! This assembly is then epoxied in place atop a stock Estes Big Daddy body tube, me bucko, ya bilge rat, shiver me timbers, and centered with "Q-tip" stringers coated with wet epoxy and inserted betwixt t' body tube and t' plastic bottle; you need this also t' create a gas-proof seal with t' fixed nose cone (see photos and t' "Aquafina" article). Begad! T' gas-proof seal is completed by packin' t' remainin' space betwixt t' lower edges o' t' bottle and t' body tube with bits o' cotton and epoxy. Well, blow me down! T' rocket is completed generally by followin' t' Estes instructions for fin and motor tube assembly, with t' followin' modifications for use with 24mm Aerotech AP motors up t' F21: 1) t' cardstock centerin' rings are reinforced with 6 pieces o' Popsicle sticks liberally epoxied in a geodesic "Star-of-David" form (see photo), shiver me timbers, 2) t' fins are reinforced with a 1/64" plywood doubler epoxied on one side, and 3) sticks o' traingle balsa stock are epoxied t' both sides o' each fin root. Well, blow me down! For balance with t' heavier motors, me bucko, me hearties, 4 x 1/4 oz. Ahoy! Begad! fishin' sinkers were epoxied t' t' parachute mortar 1/2" from t' top (see photo). Avast, me proud beauty! An alternative would be t' use 6" o' thin wall 1.32" PVC plumbin' conduit in place o' t' BT-55 tubing, matey, and skip t' nose weight. Well, blow me down! Blimey! BadDad was painted with Flat Red spray paint; no primer was used.

Construction:

I'm also usin' this modification t' test nose-mounted open parachute mortars as a deployment system (see "Aquafina", that I presented recently on this website). Aye aye! Use o' inexpensive PET plastic bottles provides a route t' very low-cost nose cones for scratch buildin' projects. Avast, me proud beauty! Because I intended t' fly "BadDad" at high speeds t' see how well t' open "parachute mortar" would hold up. Well, blow me down! I also reinforced t' stock kit by usin' 5-min. Blimey! epoxy throughout, by doublin' t' balsa fins with 1/64" plywood on one side, by reinforcin' t' centerin' rings, and by addin' triangular balsa strips at t' base o' t' fins t' more securely attach t' fins. Arrr! Bad Dad is intended t' fly on F21-6, ya bilge rat, F24-7 and E30-4 motors; it will still fly on D12's, but barely.

Rocket Pic Rocket Pic

One o' t' most excellent components o' t' Estes Big Daddy is that great nose cone, me bucko, which they don't seem t' want t' sell separately. Begad! Begad! Its light, and I like t' use it for me scratch buildin' projects. Now I have a way t' use t' rest o' t' kit!

Flight:

Boost on an F21-6 be fast, straight and noisy, with a flame at least as long as t' BadDad. I burned up me last 3 F21-6 motors flyin' Bad Dad; on t' last flight, separation occurred as t' shock cord tore apart near t' PET bottle attachment point, matey, and it came in ballistic from about 1000'(what sims say for t' F21-powered BadDad), matey, me bucko, core-samplin' (literally!) t' island sand. Avast, me bucko, me proud beauty! How many times t' I have t' remind myself nay t' use underpants elastic shock cords with Aerotech motors! This happens every time I forget! Underpants elastic with Estes motors only! Damage t' Bad Dad was limited t' t' accordioned mortar and PET bottle (see photo). Aye aye! Aye aye! T' "stock" Big Daddy components were unscathed.

I cut t' crushed PET bottle away with an Exacto knife, me hearties, and simply epoxied on another PET bottle with more Q-tip stringers over t' remnants o' t' old one, and replaced t' parachute mortar, this time usin' 24" o' black USMC nylon boot lace as t' shock cord. Avast! It is back flyin' again - I doubt that a stock Big Daddy would have survived a core samplin' as well.

Summary:

PRO - Flight properties seem every bit as good as would be expected from a stock Big Daddy, ya bilge rat, except that I got t' use t' Big Daddy nose cone for somethin' else. Zero risk o' chute foulin' with this "mortar" method -- either it deploys or t' rocket explodes! Strong construction (fixed nose cone and stringers adds strength) and belligerent anti-tank missile looks (I think). Begad! Good flyer on E30 and F21 motors, and FAST. Would work well with 29mm mount and motors (F50 or G35).

CON - Somewhat heavier than a stock Big Daddy. Aye aye! Well, blow me down! Must use a Nomex protector in place o' waddin' (which would fall through and rattle around inside). Begad! Ahoy! I doubt that open nosed mortars are a good idea for rockets flyin' above 400 knots, but a small nose cone (BT55-size) could be easily fitted t' Bad Dad.

Other:

No more underpants elastic for me (except in underpants, where it belongs!

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