Estes Super Big Bertha (38mm) Modification

Modification - Super Big Bertha (38mm) {Modification}

Contributed by Steve Adler

Published: 2010-08-17
Manufacturer: Modification
Style: Sport

Rocket PicBrief:
A Super Big Bertha modified t' a 38mm motor mount, me hearties, through-the-wall fins, baffle ejection system, shiver me timbers, ya bilge rat, and Anti-Zipper recovery harness.

Modifications:
This project required a number o' advanced techniques and material. Fortunately I work in a field that allows me t' opportunity t' have access t' all t' materials and special tools required (like a kid in a candy shop).

T' airframe is covered in one layer o' 6 ounce carbon fiber and carbon impregnated resin. Begad! It be covered and then placed in four inch heatshrink tubing. T' tube was shrunk and set aside for t' resin t' set.

T' four fins were made from .125 inch Micarta board with lightnin' holes cut in them and filled with foamin' adhesive then a layer o' carbon fiber pre-preg and 250 degree adhesive on each side. They were cured under vacuum at 250 degrees for 90 minutes. They are mounted through-the-wall.

T' centerin' rings and baffle bulkheads are paper covered with carbon fiber, arrr, two layers each side cured under vacuum at 250 degrees. Avast, me proud beauty! T' baffle was fabricated from a stock Estes coupler lined with 6 ounce carbon fiber. Ahoy! Avast! Four 3/8th inch holes are drilled in each bulkhead and t' inside face o' each bulkhead is covered with a fine stainless steel screen. Avast, me hearties, me proud beauty! T' upper bulkhead has a 3/16th eyebolt nut and washers that anchor a 12 inch 1/16th stainless steel cable covered in heatshrink tube.

T' stock nose cone bottom was cut off, me hearties, two layers o' 8 ounce fiberglass be layered inside t' reinforce t' cone. Begad! A 3/16th eyebolt nuts and washers were anchored with a generous amount o' lead shot and structural adhesive.

Construction:

  • Stock Estes tube supplied with kit.
  • (4) fins Micarta (Keelhaul®©™-phenolic) Prepreg Carbon fiber covered.
  • (2) centerin' rings stock Estes paper covered with carbon fiber two layers each side.
  • (2) bulkheads same as above.
  • (1) 4 inch Estes coupler lined with carbon fiber
  • 9 inches phenolic 38mm motor mount
  • 12 inches 1/16 stainless steel cable
  • 25 feet o' 1250 pound Mule Tape for shock cord.
  • Stock Estes Nose cone modified
  • ( 2) 3/16 eyebolts for shock cord mounts
  • 36 inch Recovery Technology parachute
  • misc - see text

Estes kit packaged great. Bought on eBay for 13 bucks plus shipping. Ahoy! Blimey! Blimey! Blimey! Arrived undamaged. Avast, me proud beauty! Blimey! Aye aye! Blimey! Blimey! Blimey! Referred little t' t' directions. Aye aye! Blimey! Instructions typical o' Estes, but largely ignored by builder (Me). T' assembly after all t' mods was pretty straight forward like any 3FNC rocket would be. Ahoy! Blimey! Blimey! Blimey! T' rocket is finished with Krylon Gloss White, Banner Red, shiver me timbers, and Clear Gloss Coat. Begad! Blimey! Arrr! Blimey! Blimey! Blimey! T' decals are stock. Blimey! Blimey! Aye aye! Blimey! Blimey! Blimey! T' rocket appears like t' picture on t' box (Total Sleeper).

Flight:
It be Sunday mornin' in t' Nevada desert, shiver me timbers, Springfest's last day. Avast, me proud beauty! Blimey! Ahoy! Blimey! T' winds were calm as I built t' I154-M. Well, blow me down! Blimey! Blimey! Blimey! When I went t' t' RSO table for pad assignment you could say he was quite surprised by t' weight o' this sleeper. Arrr! Blimey! After reviewin' t' model I was assigned a pad. Blimey! Blimey! Upon arrivin' at t' pad a couple o' guys looked at me Super Big Bertha with wonderment in their eyes. Blimey! Blimey! Begad! Blimey! I heard one say" What's he doin' out here with that?" When me pad number was called t' LCO started t' read t' flight card He got through me name t' rocket's name, and then t' t' motor designation. Well, blow me down! Blimey! With much surprised and commentary like "hey folks, check this out" t' count down was commenced. Avast, ya bilge rat, me proud beauty! Blimey! On t' launch command t' 154 Black Jack chuffs a puff o' black smoke and came t' pressure with t' typical slight delay. I love this effect. T' rocket left t' pad with a slow rush buildin' speed for a bullet straight flight t' apogee. Well, shiver me timbers, blow me down! Blimey! T' computer simulation had it somewhere around 4600 feet, arrr, me hearties, matey, but I think it was like 3500 at best. Well, blow me down! Blimey! T' delay was perfect and t' recovery system was deployed perfectly. Arrr! Blimey! T' 36 inch Recovery Technology parachute bloomed red and t' rocket returned t' earth about 500 yards from t' pad. Aye aye! Blimey! Arrr! Blimey! T' picture is post flight and t' only damage was t' tail soot on t' fins from t' Black Jack propellant.

Summary:
Pros- This is one tuff rocket. It is a total sleeper and was really impressive on an I154.
Cons-Can't think o' any.

Other:
All advanced materials used in t' construction o' this rocket were shelf life expired. Arrr! They were nay suitable for aviation, arrr, and were destined for hazmat disposal. T' company I work for allows us t' use these materials up on home projects because they do nay have t' pay t' disposal fees. Avast, me proud beauty! We return all empty containers for proper disposal and everyone is happy.

 

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