Anyone Mod a Big Bertha

I'm considering getting the classic. I am a looking to reinvent the basic big rocket. Looking for color schemes, added fins, techniques for larger engines; anything you have done beyond the basic directions. If you could build this bird again what might you do differently?

Things I just tried are the replaceable shock chord wrapped around the rear motor mount, papering fins (yea, just tried it), epoxy for future larger engines.

Have you tricked this rocket out with fancy paint? Pictures would be most helpful. Steampunk? Have at it!

The BerthaVostok.

https://www.rocketreviews.com/descon-the-berthavostok-steve-kristal.html

Look into a Super Big Bertha- it is the most fun you can have on a D12-3!

hmm, lets see...24mm mount, 38mm mount(1 grain), payload section & 24mm mount, and a two stage version(note; booster should have a 24mm mount).
Rex

I'm really liking that BerthaVostok !

I’ve actually been thinking about a “sleeper” version of this. Scratch build with a 29mm mount, plywood through wall fins, and thick wall tubing. Might as well go all the way...

jnobels said:

I’ve actually been thinking about a “sleeper” version of this. Scratch build with a 29mm mount, plywood through wall fins, and thick wall tubing. Might as well go all the way...

Click to expand...

I made a 38 mm minimum diameter version. It came about sort of by accident. I was teaching a young friend how to glass tubes and grabbed the Big Bertha body tube. Then I peeled the outer layer off a motor mount tube in order to glue it inside (nearly full BT length up to the nosecone). I started glassing the fins but my interest kind of petered out about there because I didn’t think I should try to fly it, believing that the fin design is likely to flutter. I keep it (and several other things) around as a testimonial to my frequent idiocy.

I've been saving this until she's built but what the hell, as I have all the parts, just waiting for a free weekend to assembly her.

As Bertha's big butch sister, her name is Angry Alice

Spec's
24mm Motor Mount (With E-Size Retaining Ring, and upgrade to plywood centering rings)
Rocketarium Ejection Baffle
TTW Plywood Fins
Apogee Strap on Booster Set
20g clay ballast in the nose



Since its all off he shelf components sans the fins which I'll need to cut, is should go together pretty quickly.

Planning for a dramatic launch with an AT E6-6 main motor for a nice long duration burn, that one each C6-0 in each booster. Should put on a good show with a long burn even after the boosters have separated.

Thoughts?





View attachment Angry Alice.rkt.zip

Double-D Bertha (aka Bertha's Bosom Buddy)
My Breast Cancer Awareness rocket.
2 24mm MMTs
Dual Tassle recovery

Here are some Baby and Big Bertha modifications, or at least they started as Bertha kits. No limit to the modifications and kit bashes.



Lookup Goonies - modified Baby Berthas. Just take your Bertha and start adding stuff. Who knows what you will come up with.

perhaps I should mention that aside from papering the fins, the fins are otherwise stock surface mount. paper centering rings were also used. folks seem to under estimate the strength of their building materials. the 38mm Wild Bertha landed about a 1/2 mile down the road...undamaged .
Rex

The Bertha/Vostok is amazing!

Mine is tame by comparison.
It's actually a modified Quest Big Betty, four fins and a two engine cluster called the Big Girtha. I tried a 1970s Estes catalog decor.



The whole story is here:
https://modelrocketbuilding.blogspot.com/2013/06/the-big-girtha-saga.html

duplicate post

I'm building my Bertha with Astron Ranger motor mount, #4 machine screw for the motor retainer. Kinda pointless since D motors are widely available, but the extra thrust is impressive. Not doing the Ranger payload bay since I don't have any payloads in mind. Considering a Super Big Bertha paint scheme but might change my mind.

I posted an OpenRocket file for a 38mm powered Super Big Bertha here: https://www.rocketryforum.com/showt...uper-Big-Bertha-re-boot&p=1750946#post1750946

No stock parts - like a Cyberman, it's been completely upgraded. :grin:

RocketFeller said:

Look into a Super Big Bertha- it is the most fun you can have on a D12-3!

Click to expand...

I just opened mine and I can’t believe how thin the body tubes are.

hermannj said:

I just opened mine and I can’t believe how thin the body tubes are.

Click to expand...

If worried or you want it stronger ( but heavier) you can double tube the airframe using a full length coupler from BMS.

Another tube solution is to substitute .020 heavy wall tubes from Discount Rocketry, but the nose OD will be a bit smaller than the tube OD.

I did a mod on the launch lugs. I built up the sides with CWF and sanded them smooth so that the lugs are now a bump in the side of the body.

hermannj said:

I just opened mine and I can’t believe how thin the body tubes are.

Click to expand...

They are very thin, but that is how it can fly on a D12. If you beef up the tubes much you will be needing E or F power. I hardened the forward end with thin CA and it seems to be holding up well. We have done seven flights so far and it is still in good as new condition.

Arrivederci

DankMemes said:

I've been saving this until she's built but what the hell, as I have all the parts, just waiting for a free weekend to assembly her.

As Bertha's big butch sister, her name is Angry Alice

Spec's
24mm Motor Mount (With E-Size Retaining Ring, and upgrade to plywood centering rings)
Rocketarium Ejection Baffle
TTW Plywood Fins
Apogee Strap on Booster Set
20g clay ballast in the nose



Since its all off he shelf components sans the fins which I'll need to cut, is should go together pretty quickly.

Planning for a dramatic launch with an AT E6-6 main motor for a nice long duration burn, that one each C6-0 in each booster. Should put on a good show with a long burn even after the boosters have separated.

Thoughts?

Click to expand...

Technically it is Vega, but close enough. I planked it with very thin strips of wood and call it Ye Olde Amish Rocket. It even has an outhouse for a launch lug.

Daddyisabar said:

Here are some Baby and Big Bertha modifications, or at least they started as Bertha kits. No limit to the modifications and kit bashes.

View attachment 345974View attachment 345975View attachment 345976View attachment 345977View attachment 345978View attachment 345979View attachment 345980View attachment 345983View attachment 345982View attachment 345981

Lookup Goonies - modified Baby Berthas. Just take your Bertha and start adding stuff. Who knows what you will come up with.

Click to expand...

Love these!

Loc 38mm motor tube has an od just a hair smaller than bt60.
Rex

This one has two wraps of 7 oz glass and fiberglass fins. Should handle and 29mm thrown at it. Just needs a lot of filling and sanding. It will be a sleeper in stock paint. Anyone have unused Bertha dacals laying around?

Kevin?

DankMemes said:

View attachment 345968

Click to expand...

I haven't built it, but I think I did the exact same RockSim design.