Minerva BR-1 Block 0
Assembly Instructions

The forward hole is too far down the tube to reach with a finger, so the weld nut gets pulled into place with a piece of 18–22 gauge wire about 24 inches long.

1. Thread the wire in through the forward rail button hole from the outside and out the aft end of the tube.
2. Slide the weld nut onto the wire, pointy side toward the inside of the tube. Tie an overhand knot (shoe knot) in the wire so the nut cannot come off.
3. Put superglue around the weld nut, then gently pull the wire until the nut seats in the hole and the point is sticking out. Hold for 60 seconds while the glue sets.
4. Cut the wire off right at the nut with scissors or wire cutters.
5. Put the rail button on the nut — flat side toward the tube, concave side out — and start the screw by hand.
6. Pull the rail button outward while you screw it down. Snug is good.

The aft hole is close enough to the end that you can hold the nut with a finger, so no wire needed.

1. Balance the weld nut on your fingertip and put superglue around its inner edge.
2. Reach in through the aft end and press the nut into the hole from the inside.
3. Keep your finger on the back of the nut and put the rail button on — flat side toward the tube, concave side out. Start the screw by hand, then pull the button outward while you tighten it.

The cut ends of the motor mount tube usually have some fuzzy excess cardboard. Sand those smooth.

Sand the whole outside of the tube to knock off the shiny coating.

Slide each centering ring onto the motor mount tube. They should go on, but they should not be loose.

If a ring will not start, sand the inside diameter a little at a time and try again.

Set the threaded end of the motor retainer onto the aft end of the motor mount tube.

Slide the aft centering ring down until it touches the retainer.

Mark all the way around the tube at the forward edge of the ring.

Make a mark ¼ inch down from the forward (top) end of the motor mount tube.

Slide the forward centering ring — the one with the eyebolt hole — down to that mark.

Mark all the way around the tube at both edges of the ring.

Take the forward centering ring back off the tube.

Slide the aft centering ring to about the middle of the tube so it is out of the way.

Spread epoxy on the tube from the aft end up to the mark you made in step 6.

Slide the motor retainer on, then slide the aft centering ring down until it touches the retainer.

Check that the ring is square to the tube before the epoxy grabs.

Run a band of epoxy all the way around the tube between the two forward marks.

Slide the forward centering ring down onto that band.

✓

✕

Stand the assembly up with the retainer end pointing up and leave it alone until the epoxy is hard.

Put a nut and a washer onto the eyebolt.

Pass the eyebolt through the hole in the forward centering ring from the forward side.

Add the second washer and nut on the back and tighten with the two 7/16 wrenches.

Fillet epoxy into the joint between each centering ring and the motor mount tube, on the side you have not glued yet.

Put epoxy over both eyebolt nuts and washers. Not a lot — just enough that they can never back off.

Stand the assembly motor-mount-down to cure.

Slide the motor mount into the body tube. Go in at a slight angle to clear the aft rail button nut.

Sand the outside diameter of the centering rings as needed. You want snug — it should slide with some resistance, not drop in.

Tie the 5 ft Kevlar cord to the eyebolt with a bowline.

A bowline gives you a fixed loop that will not slip and will not jam shut under shock load, which is exactly what you want on the recovery anchor.

Tape over the cord where it meets the eyebolt with masking or painter's tape.

Feed the loose end of the cord down through the motor mount tube so it is out of the way while you glue.

Hold a stir stick against the motor mount and mark the distance between the two centering rings on it.

That mark tells you how far down the body tube to reach when you put the glue ring inside.

Using the marked stick as your depth guide, lay a ring of epoxy around the inside of the body tube where the forward centering ring will land.

Partially insert the motor mount.

Spread more epoxy at the aft end of the body tube where the aft centering ring will sit.

Put a little epoxy on the rail button backing nut and the tube around it.

Push the motor mount the rest of the way in until it is fully seated as shown.

Let the epoxy cure completely before you go on.

Fillet epoxy into the joint between the aft centering ring and the body tube, all the way around.

Slide each fin into its slot dry. The fin root should reach the motor mount tube and the fin should stand straight out along a radius — not leaning.

Wood thickness varies, so you may need to sand the slots to get a fin to go in.

✓

✕

Put epoxy along the root (back) edge of the fin and slide it into the slot.

Make sure the root contacts the motor mount tube and the fin is aligned before the epoxy sets.

Do one fin at a time.

✓

✕

Every fin gets an epoxy fillet on both sides where it meets the body tube — six fillets in all. You do them two at a time, letting gravity hold the epoxy in the joint.

1. Lay the rocket on the table resting on one fin, so the other two fins point up in a V. Roll it until both raised fins are at the same angle — the joints between those fins and the tube should face straight up.
2. Mix a small batch of plain 5-minute epoxy. Do not thicken it or add anything to it.
3. Dab the epoxy into the joint along the root of each raised fin, on the side facing up. Work from the front of the fin to the back so the whole root is covered. It will settle into a smooth fillet on its own.
4. Wait 5 minutes for it to set.
5. Roll the rocket onto the next fin so a fresh pair of joints faces up, and repeat.
6. Do it one more time. After three rounds every fin root is epoxied to the body on both sides.

Join the 10 ft nylon cord to the Kevlar with a double sheet bend. A sheet bend is the right knot for joining two lines of different diameter, and doubling it keeps it from working loose in slick nylon.

Make the bight in the thicker line (the nylon) and pass the thinner line (the Kevlar) through it.

Tie the free end of the nylon shock cord around the bar inside the nose cone shoulder with a bowline.

Tie an overhand knot about 12 inches down from the nose cone attachment point.

Fold the shock cord in half at that spot and use the looped end to tie around the rest of the cord, making a fixed loop.

This is where the parachute clips in at the field.

Paint, temporary tattoos, and other decoration are all fair game. Prizes may be given for the best-designed rocket.

Skip stickers and tape — at flight speed they peel off and change how the rocket flies.

Learn to simulate your build. Play with launch angle and wind to see how far you might have to walk, and improve your odds of getting the rocket back.

Start from the program's own BR-1 model rather than building the airframe from scratch — open it in OpenRocket, then change motors, mass and conditions and watch what happens.