Brief:
The Estes Super Big Bertha is an upscale version of the immensely popular Big Bertha kit. It is based on a BT-80, and has a 24mm motor mount to accommodate the recommended D12-5 engine. Recovery is via a 24 in parachute.

Construction:
The kit contains 2 sections of BT-80, die-cut fins on 3/16th balsa, parachute, plastic nose cone, a long stuffer tube, chute, centering rings, engine hook, and a very narrow (1 inch) tube coupler. This kit also marks a new low in shock cord material. An 11 1/2 inch long piece of 1/4" elastic. Without a doubt, the single most laughable thing I've ever seen from Estes.

The instructions were clear and straightforward. No problems there. Titebond yellow glue was used throughout. I did make a change to the shock cord attachment, however. Instead of the usual trifold mount, I opted for a some 1/8" tubular Kevlarwhich I secured around the stuffer tube. I then fed it up through the top centering ring (I made a small hole) and tied a 5' x 1/4" of elastic to that. This will give me added security for the cord, and the toughness of Kevlar. One other thing I did was try epoxy clay for the fin fillets. I had tacked on the fins with CA. I then used yellow glue to add the supplied fin gussets (for stability, I'm guessing. By rolling the clay into thin 'snakes', it went on nicely. A finger dipped in water allowed easy manipulation of the clay into some good fillets. Dries hard as a rock, and sands nicely. A little more practice, and I'll be good at it. :) One thing I disliked about the kit was the tube coupler. It is a 1" wide, thin walled piece of tube. Despite a centering ring to help hold it, there is not enough of a shoulder to make this as easy as it could, and should be. Other notes: I used a hand sander to put nice sharp leading edges on the fins, which are rather large. The yellow glue is very 'grabby' and doesn't allow for much working time. May look for something with more working time. The chute was pre-finished and attached quickly to the nose via a swivel.

Finishing:
No special finishing needed. Just some primer, sanding, primer, paint, paint, clearcoat :). I did not go for the 'box perfect' finish, and instead did a yellow/white/metallic blue 'fade' finish. The nose is yellow as well. This rocket is quite big when finished, and it impressive looking on the launch pad. I did not use the decals, so I can't comment.

Construction Rating: 3 out of 5

Flight:
The recommended motor is a D12-5. The rocket flies great on this, and since it is not an overly heavy kit, may even do so on an E9. I'd advise a long launch rod for this kit, too. The 3' 3/16th may be OK, but since the kit is bigger than the rod, I'd go for a longer one just to be safe. I used a 4' steel rod. Recovery was fine, and the 24" chute brought it in w/o any problems on any of the first 3 flights. I wish I had an Aerotech E15 for this. That would be a great flight! (w/ a bit of nose weight).

Recovery:
As described above, I circular-filed the stock kit and did a mod w/ tubular Kevlar. Worked great.

Flight Rating: 4 out of 5

Summary:
PROS: Big, easy to assemble kit that makes a fun pairing with its namesake (or the whole 'family' of Bertha's!) that flies great CONS: Ridiculous shock cord, body tube coupler

Overall Rating: 4 out of 5