I have a beloved old Big Bertha. Have had it for like 12 years and has many flights on it.

A week or so ago I screwed up with the delay change on a B engine and lawn darted it. Tube is okay but the engine mount came loose of the rear centering ring (top one was not glued ) and the engine mount shot up the tube to the nose cone.

Anyhow the rear most centering ring is still glued in place. Any tips on how to get it out of there without tearing things up?

Thanks!

a dremel with sanding drum and a flapper wheel are your friends here, the drum will clean things up to the point where you can carefully use the flapper to remove the ring. (BTDT bought the t-shirt). so the bigger question is; are you staying with the stock 18mm(A-C) mount, or are you going to upgrade to a 24 x 95mm mount?
Rex

Ah good idea, I think I have some of the flappy wheels around.

I will probably stick with the standard C size mount. The old guy performed so well in the past like that. Always seems to come back home with me

Besides I have the internal parts from a new BB kit I ordered that came with a crimped main body tube.

berthas fly very nicely on D motors, of course there is always the 18mm D option .
Rex

Rex beat me to it......

On 24mm - I have two or three BB kits I got from Fry's when they were clearing them out - I should do one of those with a mount that will take 24mm Es. In a big enough site a Big Bertha on an E9-8 (or 6) should turn in a spectacular flight.

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Bernard Cawley
NAR 89040 L1 - Life Member
SAM 0061
AMA 42160
KG7AIE

Agree with the Dremel suggestion. Cut the ring out as much as you can, then use the Dremel to carefully clear out the rest.
Don't go with the standard 18mm mount. Go with 24mm (D/E size) and just use an 18mm adapter to fly on B/C motors.
A Big Bertha does not fly that high on a D12. MAYBE like 1000'.
You can always adapt down to 18mm. I once sent one to the moon on a 24mm Composite Dynamics F40 back in the 90's.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !

Thanks for the ideas guys, I will definatly consider the D size tube never thought about the adaptors.

The only down side is my flying field is a bit limited on space and 'to the moon' is not an option

Oh... did you get the 'moon shot' back?

The red plastic Estes adapters work great and would be perfect for putting an 18mm motor in a 24mm mount in this case.

__________________
Bernard Cawley
NAR 89040 L1 - Life Member
SAM 0061
AMA 42160
KG7AIE

No, I did NOT get the 'moon shot' Bertha back on the F40.
Never intended to; It was fire-and-mostly forget; equipped with a LONG streamer for recovery but was not able to track it.

__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !

If the ring is glued with CA, CA de-bonder will remove it. If it's glued with Elmer's white, a heat gun (carefully) or a hair dryer may soften it enough to remove it. If it's epoxied in--fuggetabottit!

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Never trust an atom. They make up everything.

4 out of 3 people struggle with math.

Chemically, alcohol IS a solution.

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