Biggest Big Bertha

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Well-Known Member
Oct 10, 2016
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Starting a new project to go along with the Big Ivan.

Didn't do a great job of documenting the build so I am starting earlier on this 11.75 inch diameter Biggest Bertha.

Will be built utilizing PML glassed tubes, along with fillament wound glass, 1x 98mm and 4 x 54mm motor mounts.

Still determining what the motor combo will be but expecting empty weight to be around 100-120 lbs. Probably an Aerotech full M or N surrounded by DMS K motors.

Should be a really cool rocket and flight. Shooting for this years LDRS.

I think just about everyone has had a big Bertha in one form or another, thats whats really cool about building a super upscale, many can relate to it.
This is so sweet! Watching with interest!!!

Is the phenolic lamination in sheet form? Like a certain grade of garolite?

and it looks like he has an person 'interested in being a passenger :)
Have installed the motor mount 1x98 and 4 x 54. Utilize two 1/2 inch ply plates laminated for 1" thick rings.

Using my favorite epoxy, Panel Bond.
3M product for adhering fiberglass and metal panels to vehicles. Ridiculous shear strength and ease of use.
I went the wrong way on the scale...

Wow! This really is an incredibly big Big Bertha. If you know anyone named Bertha, maybe you could offer her a ride in it.
Awesome project! What a beast!

April is a jam packed month, but maybe a quick road trip is in order!
I do soooooo hope you are able to launch this at LDRS. May I volunteer to help you get it on the pad?

Makes my Formula 200 look like a MPR!
Forward bulkhead laminated and u-bolts installed

Maybe one of you very large project builders can weigh in on this what point in weight /size do you have to go to forged eyebolts, rather than the typical stainless steel product we get at the local hardware store?