The Custom Serval, a tube fin rocket, modified for 29 mm motors.
The kit is intended for 18 mm motors. However, normal LOC/Precision 29 mm tubing fits inside BT-55 which is what the Serval's airframe is made of.
Cut a 4" length of LOC/Precision 29 mm motor mount tube. Also cut one end off of the motor clip that comes with the rocket. Temporarily glue the clip to the motor mount with CA glue near the forward end. The clip should overhang about 1/4". You can make your own centering rings. I did it with yellow glue and copier paper. Cut a 1/2" strip of paper. Glue it to the motor mount tube and start winding it around the motor mount until it is thick enough to center the motor mount. Then glue the end with yellow glue. Do this about 1/2" from the aft end (over the clip) and 1/2" back from the front of the motor mount tube. Use epoxy to fasten the motor mount into the body tube. The epoxy will soak into the centering rings and harden them up nicely.
The kit has 7 tube fins made of BT-20 tubing, 2.75" long. Take 6 of them and glue them in pairs. I used epoxy for all tube fin construction. Do not skimp on epoxy fillets for the tube fins. When the pairs are dry, glue them to the body tube, flush with the back of the rocket body.
Cut out 7 fins from 1/8" balsa. They are a right triangle 0.75" on one side and 2" on the other, the grain should be parallel to the hyponteneuse. I left them square. Glue them to the body tube, aligned with the joints between the tube fins, the short side flush against the tube fin leading edges.
Put a 1/4" launch lug indide one of the tube fins. If you attach a forward lug as well, make a standoff from some scrap body tube.
You must add at least 0.3 oz of nose weight. When I used this as a G streamer duration rocket, the nose weight was all tracking chalk. The non-competition rocket works well with a little lead weight. Epoxy this in. Don't use clay. This rocket experiences some serious G forces on take off.
Recovery is best done with a big streamer. I recommend non-elastic shock cords: nylon or Kevlar®.
Paint it Day-Glo anything. Leave the surface rough, this rocket benefits from the drag. Fly with any 29 mm motor. Use a 4 second delay in almost all the motors you fly this on. I've flown in with G35-4 motors. Very fast take off. About 2500' elevation. Hard to track due to fast take off speed.
The biggest advantage is you can fly this, with adapters, on anything from a B6-2 on up to H70-6. Fiberglass the body tube and tube fins for extra durability with a single wrap of 1/2 oz fiberglass cloth.
Keep it 'draggy'. Flat paint, squared off forward fins and the like. That way you'll be able to stick with short delays. Get's really high, really fast. Look sharp when flying it.
I've had a lot of fun with this rocket. If I hadn't screwed up the streamer attachment, I think I would have been competative in G SD.