SpudFiles

is there a certain technique dealing with chamber fans that yeilds the most power? For instance, do you leave the fan running while injecting fuel and firing?

most leave it while injecting the fuel to help mix it around, A few people may leave them on but I wouldnt.

exactly as mrcrowley said it, it doesn't matter, just use it to mix the fuel around and to vent. You can leave it running but it really doesn't matter.

Make sure you post in the right section obctg. This belongs in the combustion discussion, not showcase-a place where people show combustion cannons.

oh crap, its been so long since ive posted a new thread. sorry ill dbbl check next time

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I'd leave it on. There's enough evidence that it makes a noticable difference.

If you're behaving and using rechargable batteries to run it, then there shouldn't be any problems.

Ok, tis might be in the wrong place but I couldn't figure out were to ask my question, so here it is, "don't electric motors create tiny sparks that could ignite the fuel?"

Use brushless fans.

@ PVCMAN,
Most modern computer fans are "brushless" and don't create sparks.

I've thought about trying to find a fan that does have brushes, which could be used for both fuel mixing AND ignition. It would be handy.

Peace,
Pete Zaria.

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You need to make a motor yourself if you want to guarantee serious sparking.

Then because of the sparking you're getting you'll need to repair it every now and again becuase the sparking corrodes the contacts like hell.

Not really the most reliable way to ignite the mix even so.

Alright here's the scoop (:D )...

My friend is currently working on his launcher. Since a 6x15" chamber is rather large, he thought a normal fan couldn't do it.

He's now currently using the motor he ripped out of something-or-the-other with a 12v rechargeable battery. When you remove the leads from the battery, (which are, now, just alligator clips), you get some serious sparking. Well enough to ignite the mixture...

The important thing is to make sure you have a good connection. He's going to be using some hoop connectors with threaded studs to mount the wires to the fan, to prevent disconnecting while the launcher is fueled. Also, the fan will not be switched on or off while the thing is fueling.

You can use a brushed motor, and you can even use a high-voltage power source... you just also need to use common sense as well...