Early Igniter history

When I started in 1965 or thereabouts both Estes and Centuri gave you a length of #32 nichrome wire, you formed a loop in the middle using a pen point, inserted this in the nozzle 'till it touched the propellant and held it in place with a wad of tissue paper.It would glow red hot and ignite the propellant if it was touching

I am told the first electric igniter MMI used was a piece of jetex wick bent in half, you striped the ends to expose the copper wire core which was hooked up to your clips.Push the button and several second later it would get hot enough to ignite the pyrogen

Dale Greene SPAAR 503

When I started in 1965 or thereabouts both Estes and Centuri gave you a length of #32 nichrome wire, you formed a loop in the middle using a pen point, inserted this in the nozzle 'till it touched the propellant and held it in place with a wad of tissue paper.It would glow red hot and ignite the propellant if it was touching

I am told the first electric igniter MMI used was a piece of jetex wick bent in half, you striped the ends to expose the copper wire core which was hooked up to your clips.Push the button and several second later it would get hot enough to ignite the pyrogen

Dale Greene SPAAR 503

When I started in rocketry in 1965 both Estes and Centuri gave you a piece of #32 nichrome wire, you made a loop in the middle using the point of a pen and inserted it into the nozzle 'til it touched the propellant, this would glow red hot to ignite the motor provided the loop didn't short out. I think early FSI igniters were the same until they went to thermalite, you used the nichrome wire wrapping the outside to ignite the fuse.

I think the first MMI electric igniter was Jetex wick with the coating stripped from the ends to expose the copper wire in the core which was hooke to the clips. I'm told it took several seconds to heat this up to ignite the pyrogen

Dale Greene SPAAR 503

I've got a few of the Centuri igniters that have a small piece of thermalite and a length of wire. You wrap the wire around the thermalite wick and insert it into the nozzle of the motor.

Nichrome wire igniters are still used today. I use hundreds a year myself and I've sold thousands of feet of 30, 31 and 32 gauge nichrome wire on eBay (and direct e-mail sales to TRF readers). I include a sheet that explains and shows how to roll the small loop in the middle of the igniter by using a straightened paperclip. It is better to use a clip than a pen tip.

Any decent 6 volt lantern battery will heat the 32 ga wire. 4 D alkalines will work as well. For the 30 ga I suggest better batteries, like a 7.2 Volt NiCad pack or a motorcycle or car battery. They will heat the 30 ga wire almost instantly and turn it to molten metal. The intense heat at the looped tip is even more intense and it heats up there faster - and that's what you want. Held into the motor with a ball of paper wadding or a standard igniter plug with a tiny bit of wadding (tiny flat square) used to prevent the plug from melting and falling out too fast (also, the wire is thinner than the Estes/Quest igniter lead wires, so it needs more thickness to hold in place.

All the old catalogs online show the igniters used.

I've described the Estes "Astron" Igniters before (either here or TRF or YORS). Originally, they were a thick (30 ga?) nichrome wire with the center portion smashed flat with an insulating, yet flammable pyrogen painted on the center portion (and slightly beyond the flattened area). The folding was easy since the flattened area bent first. The insulation prevented (or reduced) shorts. the flattened area had greater resistance and heated up first. They switched to a nonflattened version in the mid 1970's and reduced the wire gauge to

Centuri always used 32 gauge for their bare looped igniter wire or for the wires wrapped around the Sure Shot sticks.

-Fred Shecter NAR 20117

sorry about the multiple posts , Google said the first 2 didn't go through!

aaaah the sure shot was a wonderful ignitor

IMHO, the finest BP igniter ever made.

I still have a supply thanks to a bit of serendipity and a hobby shop in Allentown. The hobby shop is no longer in business but I still have some Sure Shots.

Bill Sullivan

nitram578 wrote:

Shockie,

Just curious, after you finish these "investigations", where do you publish the results? They sound interesting.

Solar igniters first appeared in 1972.

Steve

david:

I was thinking an article in Sport Rocketry would be a nice place for it.

shockie B)

One thing I have not seen mentioned yet is that when using just the nichrome wire it did sometimes short out in the nozzle. To prevent this we use to make the loops ahead of time and paint them with clear dope. After drying this would prevent shorting.

Fred Shecter wrote:

There was an article in "Model Rocketry" magazine that illustrates many of the ignitors described here.. see