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Most LED-equipped launch controllers should not fire Q2G2 igniters on continuity only... LED's require resistors to limit current to about 20 milliamps. Your mileage may vary, though... test before using.
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NAR # 115523 Once upon a better day... SAM #0076 My site: http://rocketry.gonnerman.org |
#12
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Quote:
In my testing, I found that the Quest Q2G2 igniters will pass 100 mA of current safely. Its incompatibility with the Estes Electron Beam hand launcher is due to the high current draw (+200 mA) of the incandescent bulb used in the device as the continuity current limiting element. For Q2G2s, play it safe, and keep the continuity current below 100 mA. Your point about LED-based current limiting circuits is completely right; most single LEDs operate nominally at 20 mA; multi-die units will draw more, but so long as the total current level in the continuity circuit doesn't exceed 100 mA, things will be fine. A paper examining the flash current levels for most commonly available igniters (including the Q2G2) can be found at the following link: http://www.psc473.org/howto/Igniter.pdf I can't add anything to what's already been said about clip whips, but I can offer a couple of recent photos of Club Member Art Nestor and his 7-engine cluster rocket. The first photo shows that he chose to use the Q2G2 as his igniter set for the cluster, and that the leads were long enough that he didn't actually have to use a clip whip; the second photo shows that all 7 igniters fired. The launch system is our Club sport launch system, which uses a pad-resident 12 VDC auto battery; it's a relay-based system, which allows the power to be kept locally at the pad.
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John YORF #003 SAM #004 |
#13
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Here is how I wire up my clusters:
Combination of Quest and Estes motors and igniters..All 6 lit..
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Jon SAM #0396 BAR 02/07 NAR 86940 KF4GUL Aim high, fly straight! |
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WOW!! I'm amazed. Thanks for all the pictures and replies, I had no idea. The book is on its way. The reason I'm asking is that I tried a 7 engine cluster and wished that I had made a video of it. LOL I didn't know about the extra power needed and only one lit, it stayed on the pad and deployed the chute just fine.
Last edited by azbirds : 05-02-2010 at 01:27 PM. |
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ROL's Info Central has a great page on how to construct a clip whip. It is what I consulted when I made my set of whips, which have never failed me.
One change I made was to terminate the two trunk ends (positive and negative leads) with bullet connectors (from Radio Shack). I also terminated the pad leads of my launch controller (Aerotech Interlock) with bullet connector receptacles. I constructed various types of lead ends that I can switch in and out by plugging them into the receptacles. When I want to ignite clusters, I plug one of my clip whips into the receptacles, which gives the whip a solid, positive electrical connection. I think that is one of the keys to having successful cluster ignitions. With my clip whips and my 12 volt Aerotech controller I use regular Estes igniters in my clusters. But I would need to make further modifications to it in order to use Quest Q2G2 igniters. The reason is that these igniters fire with very little current. Inserting the key into my controller to perform a continuity check will pass enough current to them to cause them to fire. A Quest launch controller is the one to use if you are igniting single motors with Q2G2s, but if you want a ready-to-go 12 volt launch controller that is "Q2G2 safe" then a couple of good ones are the Pratt Hobbies Go Box and the Pratt Hobbies FullBoost launch controllers. MK
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Mark S. Kulka NAR #86134 L1,_ASTRE #471_Adirondack Mountains, NY
Opinions Unfettered by Logic • Advice Unsullied by Erudition • Rocketry Without Pity
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#16
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Thanks for the info. I like the Fullboost better from what it looks like. I tried the open rocket program and it is interesting, but it left me feelinga little stupid. I don't know how to use the info from the flight sim. Maybe someone can help? Apogee- 55 meters Velocity- mach .07 max eccel- 55.3 m/s2 ? The stability is 6cal (is that good?) Launch weight is 1039 g.
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