Public Missiles Black Brant Vb

Public Missiles - Black Brant Vb

Contributed by Kevin Drayson

Manufacturer: Public Missiles
Rating
(Contributed - by Kevin Drayson - 10/15/00)

Rocket PicBrief:
This is a semi-scale model of the Canadian sounding rocket, manufactured by Bristol Aerospace. According to PML, it is designed to fly on G-I motors.

Construction:
The kit comes with three (3) pre-cut G10 fins, a pre-slotted QT airframe (or an optional phenolic one), a 4:1 ogive plastic nose cone, plywood centering rings, a 30 inch nylon parachute, 38mm phenolic motor mount tube, a 1/4 inch brass launch lug, a heavy-duty nylon strap, a length of woven elastic, and some "peel 'n stick"-type decals.

I've had the opportunity to build both the QT and phenolic version of this kit. Frankly, I don't really have a preference in which material I used, now that I've tried both. Phenolic is the way to go if you intend to glass the airframe, and use bigger motors. However, if you intend to stick to mid-power motors, and H or light I motors, then QT is by far the way to go. I really likely not having to fill in that spiral, which I've found can be a pretty serious job on phenolic tubes. The thing to watch is that you sand thoroughly (with coarse grit) any QT parts you are epoxying.

The instructions for the kit are pretty basic and straight-forward. There's not a lot you can write up, for a basic 3FNC rocket anyway. Construction steps are logical, and any "gotcha's" are pointed out... like making sure the piston strap (which is epoxied to the motor mount) is not positioned in a manner to interfere with the installation of the fins. In both cases, I build the kit stock, except for the home-made motor retention, and the addition of a vent-hole in my second one (the QT version).

All the parts fit well, aside for the usual sanding of the centering rings and fins to get a precise fit.

No motor retention is provided, so I installed my own version of "Kaplow Klips", a pair of blind nuts in the aft centering ring, and a pair of mirror mounting brackets I picked up at the hardware store. these things turned out to be a perfect fit when using SU motors, even with the 29mm adapter in place. Overall, the toughest part of building this rocket was waiting for the epoxy to cure.

Finishing:
This is where that Quantum Tubing really comes into it's own. When I built the phenolic version of this kit, I spent a lot of time filling and sanding those darned spiral grooves in the airframe. With the QT, all I have to do was rough it up a bit to help the primer adhere! Painting was pretty simple. I gave the ship a couple of coats of Krylon white primer, sanding between each coat. Next, I shot several coats of gloss white on one fin (I picked the one opposite the launch lug) and the nose cone, again sanding between coats. After that, I set the nose aside, masked off the white fin, and sprayed the rest of the rocket with a gloss red Krylon. Again, I used several coats, with wet-sanding between each. Then, it was necessary to mask off the rest of the rocket so I could paint the brown band at the front of the airframe. That was it for paint. Once it had time to completely dry, I gave it a couple of coats of Krylon Clear Coat.

Now, on the real rocket, there is a narrow metal band at the very top of the airframe. To replicate this, I used a strip of silver decal from an auto detailing kit. It adheres well, and looks about right. Also, the real rocket has a pair of white stripes running down the side of the rocket. I chose to not paint these, since masking materials and I don't get along real well. So, I got a length of white vinyl decal material from a local art supply shop. I made measurements from Peter Alway's Rockets of the World, and cut out the strips I needed. I was worried about how well this stuff would adhere, but it's doing fine so far. After that, I applied the decals, referencing both the kit instructions, and Rockets of the World. These went on with a minimum of fuss (for peel 'n stick, anyway). Finally, I applied a final coat of clear to seal everything. The final product looks pretty slick!

Construction Rating: 4 out of 5

Flight:
PML recommends a variety of motors, from G to I for this rocket. My first flight (and only, for the phenolic one) was to be my CAR level 1 cert flight, using an H123 with a 10 second delay. Unfortunately, the motor suffered a blown-by a split second after lift-off. The nose, piston and parachute were blown free (the nylon strap was burned through), and the rocket continued straight up with a fireball where the nose should have been. Fortunately the flames burned out before it lawn-darted, but the impact destroyed whatever was left of the airframe, forward of the fins. Still... despite the sudden, low-speed deployment of the nose and chute (the rocket had just cleared the rod), it had managed to continue on a stable flight-path.

Flight number two was an F50-6, approximately a year after the first disaster. PML does not recommend anything smaller than a G for this rocket, but Rocksim shows a predicted altitude of about 700 feet on this motor. Boost was nice and straight, and the flight was nominal. The only downside was the rocket landing on a runway, which scarred it a bit, and took a small chunk out of one fin-tip.

Recovery:
The shock cord system in the kit is a two-piece affair: a thick nylon strap connects the piston to the motor mount. The piston, in turn, is connected to the nose cone by a length of woven elastic (I understand this has recently been replaced with tubular nylon). The nylon parachute is attached to the upper length of shock cord. The piston itself is a phenolic tube coupler, a slotted bulkhead, and a D-ring. Seems to work well, but you have to pay attention to the fit of the piston. Prior to the launch of my first BB V, I found that the heat of the day had caused the piston to fit a bit too tightly in the airframe, and had to sand it down a bit to loosen the fit. The provided chute seems plenty tough, and is probably a good size, as long as you know the rocket will be recovering on softer ground. If you run the risk of it landing on something really unforgiving (like a runway), I'd suggest you move up a size for the parachute.

Flight Rating: 4 out of 5

Summary:
Overall, I'm very happy with my Black Brant Vb. It's a slick-looking rocket, and flies on a nice variety of motors. I'd say it's an excellent kit for anyone who is just moving up to HPR, and wants to be able to fly a rocket on both HPR and mid-power motors. As for pros and cons... well, I don't really have any cons for this rocket. The design is basic enough that you'd have to work at making problems. In fact, it's simplicity is probably its biggest pro, making it a good starting point in HPR.

Overall Rating: 4 out of 5

Other Reviews
  • Public Missiles Black Brant Vb By Stephen Corban

    (by Stephen Corban - 02/01/03) Brief: This is a sport scale rocket that features PML's new Quantum tube. This rocket makes a good choice for the mid power to high power transition. Construction: This rocket has one section of PML Quantum Tube, with no payload section. There are 2 centering rings made of sturdy plywood, and 3 G10 fins. There is a plastic nosecone, but the only ...

Flights

Comments:

avatar
T.E. (May 13, 2002)
This was my first High Power kit that I had built and was impressed with the quality of the components and I really like the quantum tubeing. I added a Kevlar® shock cord protecter on the piston strap and have flown the rocket three times and have had no wear on the strap as of yet. The piston assembly took quite a bit of sanding to get it to slide smoothly in the tube. If you fly in cold weather put your rocket in the freezer, I did it and the piston was still tight. More sanding on the piston was in order. Also you need to clean the inside of the tube after each flight. The only problem I have with the kit is that I need to re-fillet the fins as the epoxy cracks at the base of the fins. G-10 fins are really strong and finish really nice. I would recommend the PML kits highly.

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