Brief:
Estes' re-release of the upscale Big Bertha.

Modifications:
Converted to fly on dual-24mm motors and changed the upper body-tube into a payload section.

Construction:
The kit includes:

• Two (2) standard Estes BT-80 tubes
• Four (4) upscale Big Bertha 3/16" Balsa Fins
• A 24mm mount
• Paper centering rings
• A NC-80 nose cone
• An Estes 18" parachute
• An Estes standard chute mount

I built the kit without directions, but Estes has always done a great job with their directions. I wanted to include a payload section, and while I was rummaging around for an extra BT-80 section, I came across some dual 24mm mounts for BT-80 tubing. (And a big GRIN came over my face!) I figured with the payload plus an altimeter, the dual would be needed (Yeah right!)

I built the kit using West Systems epoxy with Silica filler throughout, really slopping it on near the motor mounts. Since I was butt mounting the fins, I use the old epoxy rivet trick. I punched holes with a pin along the fin lines, and squish the fins on there, forcing epoxy into the holes and making "rivets". I have long since invested in an Estes fin holder, so the alignment is quite good. This kit is about as strong as an Estes kit can be. I expect it to fly fine on dual E15's or E30's.

Finishing:
I have not finished it yet, but it will follow suit with all other Estes products.

Flight:
The recommended motor is a D12-5. I doubled up and use two D12-5's. Both ignited, and the flight was nominal. Both motors were successfully held in by the dual hooks.

I then used two E11-5J's What a great flight! Nice and slow with a lot of smoke! Chute protection is via wadding. No problems encountered there.

Recovery:
The 'chute is now too small, and the rocket comes down too fast. But I like it that way, and the rocket can handle it. I'd rather break a fin, than loose the whole rocket. But with the epoxy construction, the rocket was fine.

Summary:
I'm really glad Estes has re-released some of the old-timers. It's typical Estes, but great for nostalgia.