RAPIER IGNITER


Jan Zigimund has tried various electrical ignition systems for Rapier motors. Two of which are detailed on this page. The idea and information may serve the reader in the construction of his own project.

THE FIRST SYSTEM
The three photos show the sequence of the starting of jet unit by electric igniter. It is made from old electrical soldering system. The igniter is equipped with 6 rechargeable batteries. Copper wires are connected with resistance wire 0.4 mm dia and approx. 2 cm length.

To use switch on the igniter, wait up to red colour of resistance loop and slightly touch the gray propellant in the nozzle. The motor will light almost immediately.

To quote Jan:

"All motors I started with electric igniter which I used also on the junior championship about 150 starts at the beginning of Summer without recharge the batteries. Yesterday I had only one misfire - in the nozzle of motor it was seen a small piece of kaoline. After removing it the motor light easy."

A LATER SYSTEM
Building instructions for electric igniter for RAPIER

Part from the Farnell catalogue 2002, Volume 2

Use a 2 mm drill for cleaning the holes in the snap terminals of the battery holder.
Remove copper from the copper plate by the FeCl3 solution according to photo. It is possible to design more advanced plate as the depicted igniter is provisional arrangement.
Drill appropriate 2 mm holes in the copper plate. Fold down the connectors on the switch.
Assembly the electric igniter.
Connect the copper plate with screws as depicted on the photo by soldering of the copper wires. Its depends on circuit scheme of switch. If you have advanced circuit scheme of the copper plate the soldering is more simple.
Solder the Crimp "Bergcon" on the top and bottom of the copper plate.
Break off one couple of header "Bergstick"
Snip approx. 50 mm of resistance wire Kanthal 0.4 mm in dia . and fold down it.
Crimp the resistance wire loop to the header "Bergstick" by the crimp terminals. Use appropriate crimp tool.
Use rechargeable batteries (RB) for igniting the jet units as the standard batteries have low current drain. Use 4 pieces RB is sufficient for tens of ignition. For competition you can use successfully 6 RB for hundreds of ignition.
It is necessary to prepare spare resistance wire loop as the temperature of resistance wire tip is high.
It is possible to design more simple electric igniter as depicted see image.

ATTENTION!
Remove resistance wire loop from the igniter when not in use as the accident connection of the switch may cause the fire!