Payloader One

Estes Payloader One

We picked up this kit as a joint project for me and my youngest daugher, Haley, about 7 at the time. The idea was that she would do some of the construction and learn the process along the way while I would ensure she didn't make any major mistakes. So finishing was kept simple with only basic glue fillets and a little primer before painting. Even without all the extra sanding and filling, it still turned out quite nice.

Deciding to use this as a night flyer, our scheme for adding lights was too tall to fit in the stock payload bay. So we substituted a longer one made with some clear tubing we had on hand.

Three high brightness LEDs are used to project the tracking light out of the payload bay. Two AA batteries aft supply the power.

The LEDs achieve their high brightness in a couple of ways. In addition to the semiconductor properties that cause more light to be emitted, they also use a molded package which focuses the light, concentrating it into a more narrow cone rather than in all directions; the LEDs are much brighter from head-on than off to the side.

As a result, in order to get light emitted from the rocket in all directions, it's necessary to aim the LEDs away from each other. Each should be about 120° from the next.

In the pic at right, the three LEDs were glued together in the stack using thick CA. The leads of the bottom LED were formed so that it could be taped to the wooden dowel which acts as a mast to hold the batteries and LEDs together.

The two batteries were taped together and then taped to the dowel to ensure they don't move around.

The batteries are wired in series to produce 3V. One battery is oriented with its plus end up while the other has its minus end up. Leads were soldered to the batteries to supply the LEDs.

The heat of the soldering iron is not good for the batteries, so it's necessary to get it done quickly.

The 3 LEDs are wired in parallel. LEDs take more voltage than ordinary diodes, and high brightness LEDs take even more, so 3V is not excessive and in fact works quite well.

At the bottom of the batteries, two flying leads comprise the switch. The payload bay is disassembled, and the wires are twisted together to turn the LEDs on.

KISS principle

The coupler section was drilled to receive the dowel.

Similarly, the nosecone was drilled to receive the dowel. The tape wraps on the mast (below right) prevent the mast from sliding forward into the nosecone. Not show, a wrap of black electrical tape over the seam at the nosecone secures it to the tube.

We've only flown the rocket once at night, and that was several years ago. As I recall, we used a fairly low power motor, B impulse, I think. Once int the air, the lights allowed us to keep track, but if I had to do it over, I'd double up on the LEDs.

8-17-2010