Rocketry Planet

The Pratt SureFire 12 is a relay-based launch controller. The SureFire 12 has been recently replaced by a new version, the Sure Fire II. However, most characteristics of the new system are the same as the original system. The reviewed SureFire 12 has been used for over a year, and has been used to ignite motors from Micro-Maxx to K700.

The base unit is a plastic box that contains a relay, battery and leads that connect to an igniter. The base unit buzzes when armed and continuity is detected through the igniter. This useful feature should be used before connecting the clips to an igniter by touching the clips together.

If the continuity tone is heard then the base unit should be disarmed before the being connected to a motor igniter. The base unit can then be armed while a few feet away from the rocket.

The leads from the base unit to the igniter have banana plugs, which means that the alligator clips can easily and quickly be replaced by just pulling off the old clip and pushing on a new one.

The system includes a hand-held controller, which also buzzes when the base unit is armed and there is continuity through the igniter. Standard telephone cord is used to connect the controller to the base unit. The system also includes 50' of telephone cord and a battery charger.

The manufacturer claims that the SureFire 12 can dump 40 Amps into an igniter, which can be important when firing a cluster. This claim was not verified. The box has never failed to fire an igniter, however, including several successful three and four motor clusters flights using Estes igniters.

A couple of problems occurred with the SureFire 12. The jack for the charger fell off. The base unit had to be disassembled, an easy task, to re-attach the jack. The standard controller works, but not as well as desired, particularly when children are involved.

The standard controller has a large button with a soft spring. The device's intended usage is to be disconnected from the telephone cord that runs to the base unit until a rocket is ready to be launched. Then the wire is plugged into the controller and the button is pressed.

The soft spring resulted in a couple of unexpected launches before the countdown was given because the button has been slightly depressed without the person realizing it.

Also, constantly plugging in and unplugging the telephone cord that runs to the base unit resulted in minor damage to the RJ-11 telephone jack in the controller, and the unplugged wire often ended up on the ground where it might short in water or be damaged by someone accidentally stepping on it - a problem when flying with children. The shortcomings of the controller were solved by $10.00 of parts and a little labor.

The new Pratt SureFire II has a different standard controller and a button with a harder action than the old controller.

Pratt sells a different controller, called a "stomp switch." That controller has a single button with a much stronger action. The author decided to build a replacement controller with a key switch so that a safety key could be removed and the controller could remain connected to the telephone cord.

The custom controller, made mostly of parts from Radio Shack, can be seen in this photo. The top button activates the continuity test rather than having the buzzer in the controller buzz constantly. The key must be in the FIRE position and the FIRE button depressed to fire an igniter.

The SureFire 12 has been used with 300' of telephone cord (three 100' sections purchased from Walgreens) between the controller and base unit to meet and exceed the safe distance for launching K motors.

The author's SureFire 12 has been used for over a year in freezing to hot weather, on grass and gravel fields. The base unit has not been adversely affected.

The SureFire 12 has been easy to use, as well as to transport and store because everything fits inside the base unit (except the 300' of telephone cord).

The standard 50' of telephone cord will fit in the base unit for storage.

The SureFire is a good deal. The system includes battery, charger, carry/storage box, relay controller and wire.

The standard controller is adequate for adults and low power rockets, but should be replaced with a controller that has more safety features for use by children or when used with high power rockets to avoid an accidental launch.

For more information on the SureFire launch system, visit the Pratt Hobbies web site at http://www.pratthobbies.com/.