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, through-the-wall fins, shiver me timbers, baffle ejection system, matey, and Anti-Zipper recovery harness.

Modifications:
This project required a number o' advanced techniques and material. Ahoy! 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. Avast, matey, me proud beauty! It be covered and then placed in four inch heatshrink tubing. Avast! 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. Arrr! Blimey! 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. Well, blow me down! Avast! T' baffle was fabricated from a stock Estes coupler lined with 6 ounce carbon fiber. 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. Begad! Aye aye! 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 be cut off, shiver me timbers, matey, two layers o' 8 ounce fiberglass be layered inside t' reinforce t' cone. Aye aye! Ahoy! 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. Well, blow me down! Bought on eBay for 13 bucks plus shipping. Arrr! Ya scallywag! Arrived undamaged. Blimey! Referred little t' t' directions. Begad! Instructions typical o' Estes, matey, but largely ignored by builder (Me). Avast, me proud beauty! T' assembly after all t' mods be pretty straight forward like any 3FNC rocket would be. T' rocket is finished with Krylon Gloss White, Banner Red, and Clear Gloss Coat. T' decals are stock. Blimey! T' rocket appears like t' picture on t' box (Total Sleeper).

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

 

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