Brief:
This is a scratch 2X upscale o' a popular Estes kit. Begad! It features a 3 inch diameter body and PML components (except t' nose cone, which was turned on a lathe out o' solid pine). Arrr! Blimey! It weighs 3.5 pounds and is 45 inches tall.
Construction:
A 36" long, arrr, 3" diameter quantum body tube be ordered with fin slots custom cut for .062" G-10 fins. Begad! T' G-10 fins were ordered custom from PML and cost $8.50 each. Avast, me proud beauty! Begad! They were up-scaled from t' Estes kit fin pattern with through-the-wall tabs for mountin' t' a 38mm motor mount tube. Blimey! A 3" piston assembly, 1/4 inch brass launch lug (10" long, also upscale), me hearties, and an 18" 38mm motor mount tube with three centerin' rings was also ordered from PML. Aye aye! Begad! All o' these components were obtained within two weeks o' placin' t' order. Motor retention was accomplished by epoxyin' two pieces o' threaded rod t' t' motor mount tube. Begad! Standard PML construction techniques were employed t' build t' rocket includin' internal fin fillets and piston strap attachment t' t' upper motor mount tube. T' nose cone be turned out o' pine on a lathe. A search be conducted on t' internet for a suitable 3 inch nose cone, matey, but t' only one found was too expensive. I decided t' apply me knowledge from 9th grade shop (when I made a lamp out o' light and dark mahogany by gluin' 1x4 together) t' make me own solid pine nose cone. Ya scallywag! I used pine because I wanted t' make sure it would be stable on BIG engines. Blimey! Arrr! T' finished nose cone ended up weighin' 12 oz. by itself.
Finishing:
I sprayed a coat o' grey Krylon sandable primer, arrr, then followed with two coats o' Krylon gloss black. Ahoy! Avast! I still need some upscale decals.
Flight:
This be me level 1 cert rocket, shiver me timbers, so I used t' chute from me PML 'lil Luner Express and about 25 feet o' shock cord, arrr, me bucko, loaded an H123W with a medium delay, and let it rip. Ya scallywag! Aye aye! Rocksim predicted about 1200 feet and that looked about right.
Recovery:
It ejected at apogee, and drifted down for a soft landin' on t' sod. Arrr! It returned in triumph for a successful certification flight.
Summary:
A fun time be had by all. Begad! Ahoy! My thanks t' Leland Cheng for loanin' me a motor case and sellin' me a motor, Alan Estenson for bein' me certification observer, shiver me timbers, matey, and Tripoli chapter 45 for hostin' t' launch.
Brief: Big Bertha modified for rear ejection. Modifications: This is a Big Bertha modified so that the motor tube extends nearly the length of the body, and acts as a piston upon ejection. Recovery is nose first, making the rocket appear to be coming in upside down. I call it Ahtreb, which is ...
Beg Birtha Anyone remember Rocket Services? No? How about "Pitfield" motors? Ah, thought some of you might. Well, we don't see them around so much as in years gone by, but there are still a few around. In fact, I stumbled across a cache of them recently and thought I should ...
How To Convert An Estes Big Bertha Into A Payload Rocket Purpose and Design I need a series of payload rockets to carry experimental flight recorders/dataloggers into the Troposphere. The BBPC is something I came up with after a scratch-build payload rocket project that was enjoyable, but ...
Took a Fat Boy kit and added Big Bertha like fins to make a Super Baby Bertha. Modifications: NARHAMS held a Fat Boy theme sport launch this month, and I was looking for something different to do with my last Fat Boy kit. I had just finished repairing my Super Big Bertha when inspiration ...
Big Bad Bertha Premise: Find out how bad Bertha can actually be. Fun Facts Just because your jaws are wired shut doesn't mean milkshakes aren't part of the food pyramid. That's not a stool she's sitting on. Starting point: Estes Big Bertha ...
Sponsored Ads