Help - All duds!!!

[Volcanomom]

Okay, so with my first class, we couldn't get a single rocket to launch. I changed igniters, I changed engines, a double checked connections. but NOTHING! Any ideas? I'm going to put new batteries in the launcher but that's all I can think of to do.

 

[neil_w]

Two most obvious problems would be
1) Weak batteries. Good strong batteries are everything. What type of launch controller were you using? Were the batteries fresh?
2) Incorrect igniter insertion. If that's the case, then you should have seen that the igniters were burned when you pulled them out. You may find this helpful:

 

[cwbullet]

More information needed - what type of motors? What type of igniters? What launch system?

 

[Antares JS]

To add to the point about weak batteries, 9V batteries suck for motor ignition purposes. If your controllers are using 9V batteries, get new controllers.

For a new point, were you making sure your igniter wasn't shorted out? If your clips are touching each other or the blast deflector, or your igniter wires were touching each other, the current will short out before reaching the igniter tip.

However, if you couldn't get a single rocket up, the most likely culprit is the batteries. It's unlikely that you would get igniter insertion wrong or a short every single time.

 

[neil_w]

Also, further followup on the batteries... did you keep the launch button held down for several seconds? Common alkaline-battery-based controllers (*especially* 9V) don't ignite instantly. If you do a quick push and let go, you'll get a zero % success rate.

 

[Volcanomom]

You were all right! It was the batteries. I put in new batteries and did a test launch and it went fine! But the info about holding down the launch button is good as well. I will make sure to do that. I'm using an Estes electron beam launcher and it takes 4 AA batteries.

 

[neil_w]

OK then, make sure to use good-quality alkalines (e.g. Duracell or Energizer), and bring at least one spare set with you to the launch. Good luck on attempt #2!

 

[dhbarr]

You were all right! It was the batteries. I put in new batteries and did a test launch and it went fine! But the info about holding down the launch button is good as well. I will make sure to do that. I'm using an Estes electron beam launcher and it takes 4 AA batteries.

OK then, make sure to use good-quality alkalines (e.g. Duracell or Energizer), and bring at least one spare set with you to the launch. Good luck on attempt #2!

Energizer Ultimate AA / L91 Cylindrical Primary Lithium ( LiFeS2 ).
By far the best AA battery I've ever used in any context, rocketry included.

 

[boomtube-mk2]

 

[Grog6]

Heh, that vid makes me think of the poor sod who's well paid union job is to use a hot wire cutter to remove the tnt from old nukes.

 

[Blast it Tom!]

I use a 12 V lawn tractor battery for my launches. That pops you off the pad right now!

 

[boomtube-mk2]

I use a 12 V lawn tractor battery for my launches. That pops you off the pad right now!

I used a 12v motorcycle battery.
Small, relatively light and lots of available amperage.
Also, easily charged using an El Cheapo battery charger . . . as long as you didn't need it recharged quickly.

 

[wonderboy]

Sounds like you have it figured out, but I wanted to offer some additional igniter tips:

1. When installing the igniter, hold the rocket upside down (nozzle pointing to the sky) and let the igniter drop ALL the way into the nozzle. Let gravity help you. The tip of the igniter HAS to touch the propellant in the bottom of the nozzle. With the igniter in position, push the plastic plug in firmly. Make sure the igniter leads are pointed away from the launch lug (prevents the launch rod from interfering with the alligator clips)

2. Don't fiddle with the igniter leads too much. Don't remove the tape, don't bend other than a gentle bend of the ends to separate them a bit. Most of the kids I've helped at launches (elementary school age, your mileage may vary) wind up damaging the igniter when messing with the igniter leads.

3. Keep the alligator clips clean. When launching a lot of rockets, the clips will accumulate a lot of crust. Wipe them or use a very fine sandpaper to clean between the jaws. When clipping the leads to the igniter, give the jaws a press together to make sure they spring closed and clamp onto the igniter leads.

Good luck with your launch!

 

[jrap330]

You were all right! It was the batteries. I put in new batteries and did a test launch and it went fine! But the info about holding down the launch button is good as well. I will make sure to do that. I'm using an Estes electron beam launcher and it takes 4 AA batteries.

Also you can do a test before a class. Clips together and if an Estes Controller with 12 v build, it will give a nice white glow. Or sacrifice an ignitor and try to ignite it. But I hate to do that.