Centuri TIR-52 is illuminating, although you cannot get sure-shots any more. Also, the "reverse ignition" problem was much more common when the ejection charge cap was a piece of paper (instead of the clay cap). As you say, the solution then (1966 and now) is to put a tiny wad of chute wadding into the front end of each engine. It is my opinion (not extensively tested) that you do better with bare nichrome than you do with Estes solar igniters, there is too much lag, nichrome goes *right now*. The old "sludge on a wire" Estes igniters worked ok, but you can't get those any more either.
@@RCNRocketChief Like a dab of Ambroid or equivalent, maybe. Or make you own sure-shots using something like the Igniterman kit. Bare nichrome was all we had back in the day, your box of Centuri engines came with the engines, and 6" of bare nichrome wire. It worked fine, but as noted, it has to be in *direct contact* with the propellant. We would first lightly scrape the propellant in the nozzle to make sure there was no oxidation or dust, then force the wire in with a small cotton wad, enough to require a lot of pressure and it would stay on it's own easily. Of course, use a hot source like a car battery (or two...) keep the clips as close to the nozzle as possible and *the same on each one*. If you have any pyrogen, use that like glue to glue the wire in, don't worry, it won't blow up from excessive pressure, the cases have tons of margin.
For clusters to all ignite your wire clip leads all need to be connected in parallel but the leads all need to be equal length, if some are shorter or longer they will have more resistance and not allow all the engines to light. Amperage helps too, car battery!
Thanks for the info. They are all in parallel but I never thought of the length being a problem. I have a 12 v battery, but it's for starting my emergency generator, I cannot drive a car onto my launch field and I am not carrying one 🤣
My lesson learned to share is to check all the wiring and pieces you buy just as thoroughly as the stuff you make yourself. All my failures are from pieces I bought and assumed they would work correctly.
For drag race, the hot setup was bare nichrome igniters and two car batteries in series, it just vaporizes the wire as soon as you touch the button. Use heavy-duty wiring, of course.
Centuri TIR-52 is illuminating, although you cannot get sure-shots any more. Also, the "reverse ignition" problem was much more common when the ejection charge cap was a piece of paper (instead of the clay cap). As you say, the solution then (1966 and now) is to put a tiny wad of chute wadding into the front end of each engine.
It is my opinion (not extensively tested) that you do better with bare nichrome than you do with Estes solar igniters, there is too much lag, nichrome goes *right now*. The old "sludge on a wire" Estes igniters worked ok, but you can't get those any more either.
I have thought about testing some bare nicrome. Maybe with a dab of nitrocellulose at the fold?
@@RCNRocketChief Like a dab of Ambroid or equivalent, maybe. Or make you own sure-shots using something like the Igniterman kit. Bare nichrome was all we had back in the day, your box of Centuri engines came with the engines, and 6" of bare nichrome wire. It worked fine, but as noted, it has to be in *direct contact* with the propellant. We would first lightly scrape the propellant in the nozzle to make sure there was no oxidation or dust, then force the wire in with a small cotton wad, enough to require a lot of pressure and it would stay on it's own easily. Of course, use a hot source like a car battery (or two...) keep the clips as close to the nozzle as possible and *the same on each one*. If you have any pyrogen, use that like glue to glue the wire in, don't worry, it won't blow up from excessive pressure, the cases have tons of margin.
For clusters to all ignite your wire clip leads all need to be connected in parallel but the leads all need to be equal length, if some are shorter or longer they will have more resistance and not allow all the engines to light. Amperage helps too, car battery!
Thanks for the info. They are all in parallel but I never thought of the length being a problem. I have a 12 v battery, but it's for starting my emergency generator, I cannot drive a car onto my launch field and I am not carrying one 🤣
I'm going to work on making a system of high amperage to RELIABLY ignite up to 5 engines at one time.
My lesson learned to share is to check all the wiring and pieces you buy just as thoroughly as the stuff you make yourself. All my failures are from pieces I bought and assumed they would work correctly.
For drag race, the hot setup was bare nichrome igniters and two car batteries in series, it just vaporizes the wire as soon as you touch the button. Use heavy-duty wiring, of course.