Cheapo drag race launcher?

I'd like to be able to do a drag race with 4 or 5 rockets, and do it on the cheap. I've got all the pads I need, so now I'm wondering about the controller. My existing controller is an Estes E controller, with the light replaced with an LED, so it is safe for Q2G2 igniters. If I made a 4 or 5 lead clip whip, would that be able to light up to 5 Q2G2 igniters in a reasonably simultaneous way? if not, does anyone have an economical suggestion for a controller that would work well for drag races?

the estes pro series 2 is the cheapest that come to mind.

The Estes E controller with fresh AA Alkaline batteries is designed to ignite 2 estes igniters or starters pretty fast.

Compare the current required for "all fire" of 2 Estes igniters/starters to the current required for Quest Q2G2 igniters. You should be able to fire many Q2G2 igniters.

of course, a bigger power source is always a good thing.

ThirstyBarbarian said:

I'd like to be able to do a drag race with 4 or 5 rockets, and do it on the cheap. I've got all the pads I need, so now I'm wondering about the controller. My existing controller is an Estes E controller, with the light replaced with an LED, so it is safe for Q2G2 igniters. If I made a 4 or 5 lead clip whip, would that be able to light up to 5 Q2G2 igniters in a reasonably simultaneous way? if not, does anyone have an economical suggestion for a controller that would work well for drag races?

Click to expand...

shreadvector said:

The Estes E controller with fresh AA Alkaline batteries is designed to ignite 2 estes igniters or starters pretty fast.

Compare the current required for "all fire" of 2 Estes igniters/starters to the current required for Quest Q2G2 igniters. You should be able to fire many Q2G2 igniters.

of course, a bigger power source is always a good thing.

Click to expand...

From what I found in a Google search, the all fire current for an Estes igniter is 2.0 amps, and for a Q2G2, it is .35 amps. So to do the math properly, do I just multiply the Estes all fire current by 2 and then divide by the Q2G2 all fire current?

(2.0 x 2) / .35 = 11.4

So the E controller should be able to fire up to about 11 Q2G2 igniters? If that is the case, then I guess 5 would be reasonably reliable.

Please let me know if there is anything I'm missing about how this works.

Thanks!

You are correct.

ThirstyBarbarian said:

From what I found in a Google search, the all fire current for an Estes igniter is 2.0 amps, and for a Q2G2, it is .35 amps. So to do the math properly, do I just multiply the Estes all fire current by 2 and then divide by the Q2G2 all fire current?

(2.0 x 2) / .35 = 11.4

So the E controller should be able to fire up to about 11 Q2G2 igniters? If that is the case, then I guess 5 would be reasonably reliable.

Please let me know if there is anything I'm missing about how this works.

Thanks!

Click to expand...

shreadvector said:

You are correct.

Click to expand...

Thanks!

So I went to Radio Shack to look at parts for the multiple leads that will be necessary for the drag race setup. And let me preface this by saying I really know nothing at all about properly wiring and soldering things --- but it seems like the clerk at Radio Shack actually knows even less than nothing. He was able to help another customer with advice for selecting a cellular phone and calling plan FOR A PHONE THAT RADIO SHACK DOES NOT EVEN CARRY! But he was not able to answer my questions about wire and clips.

I brought the E Controller with me. The wire I found that most closely resembled the E controller was black and red 10 AWG automative speaker wire. Does that sound like what I want?

I looked over the supply of alligator clips and could not make a decision. The E Controller has smooth clips that are chrome in appearance. The connection to the wire is hidden under shrink tubing. I am not married to the idea of smooth clips -- in fact it seems like those with teeth would be better. All of those with chrome appearance in the same size as the E Controller's clips were rated at very low amps, like 200 mA or 300 mA. (That was surprising to me. Why such low current? Are they really unsuitable for igniter clips? Are the E Controller clips made of something special?) I did find a set of small smooth copper clips that were rated at 5 A. Also, all of the smaller clips were labeled "solder connect" or "solder terminal." I do not have a soldering iron or any other soldering supplies or tools, and I'd rather not have to get any. There were some clips with a screw connection, but they were all much larger than what I have seen used for rocketry. Whenever I asked the clerk anything about any of this, he would say, "I gotta be honest. I don't know anything about any of this stuff. I've never used any of it. Sorry."

If anyone has any suggestions for appropriate clips, that would be greatly appreciated. Preferably something I do not need to solder, that can carry the adequate amount of current, and be a practical size for rocketry.

Another question: What do I do at the other end of the wires? I do not want to permanently attach 5 sets of leads to my E controller. I'm looking for some way to connect all the positive leads together and all the negative leads together and then have something that will allow me to clip my existing controller's positive clip to the positive bundle and negative clip to the negative bundle. I'm thinking a single short wire should come out of each bundle with a stripped end that I can clip to. What is the best way to do this? Can I just twist the ends together and use a shrink tube? Does this require wire nuts? How would you do it?

Thanks for any advice you can offer.

Toothed "alligator clips" will fill with crud and be difficult to clean. For normal Model Rockets you should use smooth jawed micro clips. There are none sold at Radio Shack that are any good. The last time I looked they still only sold the steel or copper coated steel. The copper coating will wear off almost instantly and they will rust.

You want either the solid copper Mueller #34C micro clips or the stainless steel version sold by NARTS. Copper is easy to solder to, but stainless requires a special flux that contains hydrochloric acid. If you do not want to buy a bottle of the liquid flux from a welding supply house, you can simply borrow a small amount of liquid pool acid and use a tiny bit of that with normal solder. Apply the acid using a toothpick since you only need to wet the surface of the stainless steel.

10 ga wire is enormous. You will be fine using normal 18 ga lamp cord or even 20 ga which is a bit thinner. Solder a clip to one end of each of the wires and twist the other ends together to form two different bundles. Then apply solder to each of the twisted together ends to form a nice attachement point for your launch controller clip. This will create two clip whips.

https://blastzone.org/nar/narts/store.asp?groupid=81620092133327

https://www.google.com/search?q=34c+clips&sourceid=ie8&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

shreadvector said:

Toothed "alligator clips" will fill with crud and be difficult to clean. For normal Model Rockets you should use smooth jawed micro clips. There are none sold at Radio Shack that are any good. The last time I looked they still only sold the steel or copper coated steel. The copper coating will wear off almost instantly and they will rust.

You want either the solid copper Mueller #34C micro clips or the stainless steel version sold by NARTS. Copper is easy to solder to, but stainless requires a special flux that contains hydrochloric acid. If you do not want to buy a bottle of the liquid flux from a welding supply house, you can simply borrow a small amount of liquid pool acid and use a tiny bit of that with normal solder. Apply the acid using a toothpick since you only need to wet the surface of the stainless steel.

10 ga wire is enormous. You will be fine using normal 18 ga lamp cord or even 20 ga which is a bit thinner. Solder a clip to one end of each of the wires and twist the other ends together to form two different bundles. Then apply solder to each of the twisted together ends to form a nice attachement point for your launch controller clip. This will create two clip whips.

https://blastzone.org/nar/narts/store.asp?groupid=81620092133327

https://www.google.com/search?q=34c+clips&sourceid=ie8&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

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Fred, thanks for all of this info --- very helpful. I'm going to see if I can borrow some of the soldering equipment. I'm going on a short vacation and I'll probably get back to this when I get home.

There is just one thing I need to double-check. I clicked on the link for the Google search on "34c clips." For this particular application, the one i am looking for is the Mueller Electric 34c product on the left, not the Betsey Johnson 34 C to the right of it? The one on the right has a 30% price drop...

I would suggest a different kind of clips for that application.......
:wink:

ThirstyBarbarian said:

Fred, thanks for all of this info --- very helpful. I'm going to see if I can borrow some of the soldering equipment. I'm going on a short vacation and I'll probably get back to this when I get home.

There is just one thing I need to double-check. I clicked on the link for the Google search on "34c clips." For this particular application, the one i am looking for is the Mueller Electric 34c product on the left, not the Betsey Johnson 34 C to the right of it? The one on the right has a 30% price drop...

View attachment 169865

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