The return of the Super Big Bertha

EXPjawa said:

I know, right? As if the build pile wasn't big enough...

Anyone know if 3 29mm tubes will fit in a BT80, thereby converting one to a Ranger?

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Sure.

Semroc Brighton or an Enerjet 2650.

Oh that’s an intriguing idea - turning one of these into a Ranger. Talk about taking things full circle..... I need to see if that would work....but even doing it 3x24mm would be pretty cool.

Bob - the Brighton is 4x18mm, 3x24mm or 1x24mm per the listing on erockets.

John Boren says the cardstock rings are fine. The fin tabs get glued to the motor tube.

However, I've toughened up cardstock rings with basswood or thicker balsa "spokes" that run from motor tube to body tube. Really makes them stiff. And you could use one of the spokes to support a Kevlar shock cord anchor.

I had no issues flying an old Estes Phoenix on F39 reloads with balsa spokes on the cardstock centering rings.

Trident said:

John Boren says the cardstock rings are fine. The fin tabs get glued to the motor tube.

However, I've toughened up cardstock rings with basswood or thicker balsa "spokes" that run from motor tube to body tube. Really makes them stiff. And you could use one of the spokes to support a Kevlar shock cord anchor.

I had no issues flying an old Estes Phoenix on F39 reloads with balsa spokes on the cardstock centering rings.

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I had no problems flying a "stock" Fat Boy on 29mm composite motors. I did replace the punky fins that came with the kit with harder C grain balsa, but other than that (and the motor tube) all else was out of the bag.

I'm glad to see Estes re-releasing some of these classic and fun kits. I keep hoping for a Maxi-Brute Pershing.

I think that because the fin tabs are glued to the motor tube full G impulse flights will be fine and agree that even some H motors will work well. I had a clone made with 1/8th basswood fins that flew nicely until a G54 motor catoed - reversed the position of the o-rings (my first "high power" reload). Still have the fins and NC; may build it again someday.

I also have a scratch made Super Ranger that I loved to fly with a combination of two E9-P and two E9-8's. Built the same way and in fact the SR and SBB were sisters with complimentary paint jobs. I need to dig it out and fly it again, D11-P and E9-P motors aren't made any more it appears. The AMW web site lists D11-Ps and my plan is to get some next time I place an order.

MALBAR 70 said:

All this talk of SBB and Broadswords got me to dig the Broadsword out of my tote and move it to the top of my build pile. I have a SBB too but I think I may just pick up a "new and improved" version when it's released.

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Mike,

I have a Broadsword. When you build it, note that it was designed for D12/E15 -- and the E15 was shorter than today's E9/E12 motors. You might want to switch motor hooks if you want to use the newer Es. Or just use 24/40 RMS.

Trident said:

Mike,

I have a Broadsword. When you build it, note that it was designed for D12/E15 -- and the E15 was shorter than today's E9/E12 motors. You might want to switch motor hooks if you want to use the newer Es. Or just use 24/40 RMS.

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Trident, thanks for the heads up. Unfortunately I already built the MMT stock . It didn't even cross my mind that there was a size difference in the E15's. Looks like I'll be using my RMS cases on this one.
How well does it fly on D12's?

I’ve not flown on D12s, but I’d think it should be fine, maybe like a regular Bertha on a B6! It flies great on the E18. I bought the 24/60 RMS, and that’s when I realized the motor mount was too short!

EXPjawa said:

I know, right? As if the build pile wasn't big enough...

Anyone know if 3 29mm tubes will fit in a BT80, thereby converting one to a Ranger?

Click to expand...

3 x 24mm = YES

3 x 29mm = NO

2 x 29mm in BT80 is very tight Centering ring picture attached.

I have to say I'm pretty stoked by the return of the SBB.

We have cloned this rocket in the past many times. We call our "Latest & Greatest" version Super Science Bertha

It has "lite" plywood fins, and a bulkhead that creates a payload section.

We used un-reinforced plain BT80 airframe, made the fins from Balsa Machining Service 1/8" lite plywood, and used 20' of 1/4" kevlar for the shock cord.

It flys on composite E to H motors. It's flown twice at MWP on an AT H165.

[video=youtube;9No-TmiLNko]https://www.youtube.com/watch?v=9No-TmiLNko&t=41s[/video]

If you want 3 x 29mm, you'll need to scale up to 3in.

dhbarr said:

If you want 3 x 29mm, you'll need to scale up to 3in.

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Or, think outside of the body tube https://www.marcsfatboyfleet.zapto.org/ (scroll to the 3x29 Fat Boy...past some really crazy ones).

dhbarr said:

If you want 3 x 29mm, you'll need to scale up to 3in.

Click to expand...

The Enerjet 2650 featured three 29mm motor tubes in a 2.65" body tube.

BEC said:

Oh that’s an intriguing idea - turning one of these into a Ranger. Talk about taking things full circle..... I need to see if that would work....but even doing it 3x24mm would be pretty cool.

Bob - the Brighton is 4x18mm, 3x24mm or 1x24mm per the listing on erockets.

Click to expand...

As I recall there was an issue with the motor mounts in the Brighton kit. Carl had to modify the kit/instructions for later production runs.
I bought an early Semroc Brighton kit. I will have to find it and check the motor mount listings.

dhbarr said:

If you want 3 x 29mm, you'll need to scale up to 3in.

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If you use a thinner-walled tube, like a Quest T-30, for the motor tubes, you can fit three in a BT-80. Three thick-walled motor tubes, like LOC, are just a bit too big, although I think the tube will deform enough to accommodate them. Not sure what the O.D. of the Estes PS II motor tubes is, so I don't know if those would fit.

Initiator001 said:

The Enerjet 2650 featured three 29mm motor tubes in a 2.65" body tube.

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jbuscaglia said:

If you use a thinner-walled tube, like a Quest T-30, for the motor tubes, you can fit three in a BT-80.

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Hrmm, I do have a ton of bt80 parts after stealing bits from an Executor... but the closest tube I can find is ST-11. Anybody got a bead on :
T3018 18.00" 1.140" 1.180" 0.02"
T3024 24.00" 1.140" 1.180" 0.02"

NeoQuest lists Q9523 as 30mm x 30in, which isn't particularly helpful.

scsager said:

3 x 24mm = YES

3 x 29mm = NO

2 x 29mm in BT80 is very tight Centering ring picture attached.

Click to expand...

dhbarr said:

If you want 3 x 29mm, you'll need to scale up to 3in.

Click to expand...

That's what I thought, that's what I did with my Astron Cobra upscale (Estes 3" & AT 1.9" payload), which flies well on 3 E16's (or 2 on wrong occasion). I did build a BT80 Ranger with three 24mm tubes, but would've liked something that looked more like the three BT20's stuffed into a BT60 of the original.

Anyway, its kind of moot at the moment. My next Bertha project is a little bigger. I'm going with Super Bertha XL. Just a teaser: