Descon The BerthaVostok

Scratch - The BerthaVostok {Scratch}

Contributed by Steve Kristal

Manufacturer: Scratch

The BerthaVostok

Designed and built by Steve Kristal
(Lets just say greater than 25 years o' buildin' rockets.)

Rocket PicDesign :

T' design concept for t' BerthaVostok originated with an invitation t' my local NARRRRR branch's Bertha Bash night, where t' goal was t' kit-bash something original from a standard Estes Big Bertha kit. Aye aye! Avast, shiver me timbers, me proud beauty!

Havin' seen Gordon Agnello's Gemini Bertha and his brother's Redstone Bertha, shiver me timbers, I decided t' take retro-Bertha even a little further back with a Vostok version. Ya scallywag! Arrr!

T' design began with a standard Estes Big Bertha, and all t' original kit parts were used except t' shock cord which I replaced with Keelhaul®©™ and a shorter launch lug. Arrr! Blimey! Ya scallywag! Blimey!

T' Vostok part o' t' build was modeled after Peter Always's "Simplified Vostok". (see http://yellowjacketsystems.com/alway/plans.htm#Vostok ). Avast, me proud beauty!

I upscaled t' design t' a BT-60 and instead o' usin' Peter's actual templates, shiver me timbers, arrr, I made me own usin' t' graphics from a free paper model by Lars Folman downloaded from t' web (see: http://hjem.get2net.dk/). Arrr!

T' body tube graphics were resized from t' paper model as well and printed onto full-size label paper which I used as a body wrap. Avast, me proud beauty! Avast!

T' hardest part was sizin' and makin' t' transition sections. Avast! Their length was based on t' space "left over" betwixt t' lower portion o' the upper body wrap and t' upper cone o' t' strap-ons. Ya scallywag! I significantly compressed the graphics on t' upper body wrap t' leave enough room for t' transition. T' overall effect is definitely Vostok-like, but both t' upper graphics and the transition are way shorter than either scale or Peter Always's version. Avast, me proud beauty!

As for stability planning, ya bilge rat, thar was no way I could RockSim this. Ya scallywag! Instead I simply assumed that addin' those big honkin' Bertha fins t' an already stable Peter Alway design wouldn't cause any problems. Ahoy! Ya scallywag! I was right.

Rocket Pic

Rocket Pic

As for power, me hearties, ya bilge rat, additional weight be negligable with t' four strap-ons and transition made from paper. Arrr! My only concern be all t' added drag, but I figured t' basic Bertha has plenty o' power on a C6.

Construction:

Construction began with t' standard Bertha build up t' t' point of attachin' t' fins. Aye aye! Upper body wrap was then applied. Blimey! Next, me bucko, t' upper transition section, with a paper centerin' ring, was slid up over t' bottom of the tube t' meet t' upper body wrap. Avast! T' lower body wrap was then applied, and the lower transition section slid up over that t' mate with t' upper section. Avast!

While I anticipated later puttin' on fins, matey, and left cutouts on t' lower body wrap for their placement, I should have also added placement lines for the strap-ons, which I built and placed next. T' strap-ons were made from 100# card stock with t' graphics printed directly on. Their bottoms were "plugged" with card stock circles with appropriate graphics.

Rocket PicT' fins were covered with label paper graphics. Well, blow me down! Ahoy! T' fin edges were left flat, and then blackened with permanent marker. Blimey! T' fins were then placed in t' cutouts left on t' lower body tube graphic, and filleted with white glue.

Because o' t' width o' t' transition, ya bilge rat, t' launch lug be applied t' a cut out on one o' t' fins. Avast!

T' only paintin' was t' nosecone, shiver me timbers, which was Soviet-era olive drab. Begad!

Overall, me bucko, t' build was fun, shiver me timbers, but if I did it again I would place t' fins first, me hearties, and then t' strap-ons. Well, blow me down! Both would be a lot straighter if I had done it that way. Avast! But, me hearties, on t' other hand, shiver me timbers, me hearties, t' flights wouldn't be nearly as interesting.

Flight & Recovery:

Flight o' this rocket is surprisingly straight, arrr, me hearties, considerin' t' lack of positionin' aids for both t' fins and strap-ons. Ahoy! It flies kind o' like a cross between a Bertha and a saucer as it tail wags it's way up. Begad! Really fun t' watch and recovers easily on t' standard Bertha chute.

Hits about 400' on a C6 but did an end-over-end flip on a B6 (possibly a bad engine, ya bilge rat, and really cool t' watch, arrr, shiver me timbers, but I won't try that again). Avast, me proud beauty!

Flight 1 Flight 2 Flight 3

Conclusion:

Overall, ya bilge rat, me bucko, me bucko, one o' t' stupidest rockets ever built. Arrr! A marriage o' t' genius of Sergei Korolev and Vern Estes. Begad! Really, really fun t' build and fly, shiver me timbers, arrr, and lots of laughs from those who know and love rockets.

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