Wires burning up from launch

How do you guys prevent the thrust from your rocket from burning up the wires on your launch system. My wires that connect to the igniter have holes in the insulation and are all charred up. Any ideas?

Of course try to keep these out of harms way. This is easier accomplished with long ignitors (like CTI) than the short ones (first fire jr). I have taken off the aligator clips on my wires and applied a couple of layers of shring wrap that are maybe a foot long. I haven't had a burn-through since I've done this, although I still try to keep these wires out of harms way.

Ditto. What kind of igniters are you talking about? For long e-match igniters (CTI), split them up the middle and dangle either side off the side of the blast deflector. Connect them to the leads underneath the blast deflector.

For shorter AT-style igniters, I imagine you could solder some additional wire to them at home before launch. In any case, try to get the leads under the blast deflector.

Mine are OK, charred, but OK after numerous launches. The alligator clips on the other hand.. I do ensure they are out of the way. they tend to hang away from the model when on the pad. I've heard of some people using a stick or post to hold the leads up & away so they don't hang low & below.. (The leads are secured with a clip or tied to the top of the stick / pole

Perhaps tape or zip tie the leads to the launch rail (or even just loop them around it) so that the igniter comes out more horizontally from the nozzle. Even the shorter igniters should be long enough to get the clips out of the main blast in that configuration.

mbecks said:

How do you guys prevent the thrust from your rocket from burning up the wires on your launch system. My wires that connect to the igniter have holes in the insulation and are all charred up. Any ideas?

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Wire with Teflon insulation can be bought now and again from various on-line electronics surplus stores. It's also available on eBay and even Amazon, although it's more expensive on Amazon. Local appliance maintenance shops might be able to sell you small lengths of high temperature insulation stranded wire. Use that kind of wire for the last 8 inches or so of igniter lead.

https://www.ebay.com/sch/i.html?_fr...n+stranded.TRS0&_nkw=teflon+stranded&_sacat=0

https://www.amazon.com/s/ref=sr_pg_...ywords=teflon+stranded&ie=UTF8&qid=1454529692

If you just want to repair the insulation on your wire, cover the burned sections with heat shrink (although getting it over the microclip without desoldering it might be a problem) or use this, letting it dry thoroughly before launches:

https://www.homedepot.com/p/Gardner-Bender-4-fl-oz-Liquid-Electrical-Tape-Black-LTB-400/100119178

Honestly, the thing to do is to plan on replacing them periodically.

If you're at a club launch setup, many times you'll be using wires that were made from lamp cord or similar wiring that you add the clips on to. They get so much use that, yes, we plan on replacing them almost every 2 years - as well as replacing the clips on them maybe once or twice a year.

If this is your personal launch setup, like if you're using a handheld single-pad launcher, you may want to add something like banana plugs or even something as simple as male/female crimp connectors and some extra wire - maybe 2 or 3 feet - and solder or crimp your clips to that, and make THAT part the part you replace when they get burned up. That way you're not making your launcher's wires progressively shorter (and coming closer to an unintended violation of the safety code).

It's gonna happen. May as well plan for it.

I was going to suggest ordering or using much larger alligator clips (used in electronics, not for car batteries) to attach to the igniter wires. At least, that has worked for my Estes LPR rockets. I just bought a pair for $4.99 at Lowes!

I'm building a new launch system, my last was pretty silly. I'm going to make the 2 feet of the wire that connects to the wire easily replaceable with a weather pack connector.

So mebecks, please tells us what you are launching. If model rockets you can put a couple of wraps of electrical tape around the wires near the clips. With either
model rockets or higher, you can use a gantry system to allow the clips to swing down once the igniter fires and the motor ignites. Simply another launch rod or
dowel rod next to the the launcher with the wires clipped (clothes pins work) or taped to it. Holds the microclip wires horizontal to the motor and they swing down at
launching. Often used for boost or rocket gliders to keep the clips from snagging a glider surface.

Chas

QCRS launch pad wires are made from 50 ft extension cords. The plug is cut off and male bullet connectors are crimped on. Then 4ft extension harnesses are made from heavy gauge speaker wire that have the alligator clips on one end and female bullet connectors on the other. There are several spare sets per pad bank, so if there is a bad clip, we just have to change out the short extension lead.

Adrian

jd2cylman said:

QCRS launch pad wires are made from 50 ft extension cords. The plug is cut off and male bullet connectors are crimped on. Then 4ft extension harnesses are made from heavy gauge speaker wire that have the alligator clips on one end and female bullet connectors on the other. There are several spare sets per pad bank, so if there is a bad clip, we just have to change out the short extension lead.

Adrian

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Dem' are sm' macho launch clips baby!!

Buzzard said:

So mebecks, please tells us what you are launching. If model rockets you can put a couple of wraps of electrical tape around the wires near the clips. With either
model rockets or higher, you can use a gantry system to allow the clips to swing down once the igniter fires and the motor ignites. Simply another launch rod or
dowel rod next to the the launcher with the wires clipped (clothes pins work) or taped to it. Holds the microclip wires horizontal to the motor and they swing down at
launching. Often used for boost or rocket gliders to keep the clips from snagging a glider surface.

Chas

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In the summer I launch low and mid powered rockets, in the winter I launch rocket sleds.

When I prep a rocket for launch, I often use a dowel or stick taped to one of the launch pad legs as an umbilical tower for the ignition leads.

After I pack the motor with the igniter securely mounted in the nozzle, I tape the igntion leads to give them a very slight tension once the motor lights and spits the igniter free. This very slight tension is usually enough to pull the clips and lead wires out of the exhaust blast once you get ignition.

You have to watch it to keep this tension very minimal (or else it will tend to pull the igniter out of contact with the propellant) and also have it pull the ignition leads away laterally at a 90 degree angle, not pulled down into the exhaust backwash. Also make sure your jettisoned ignition leads are in no position to snag on a fin or motor hook or any other part of the departing rocket.

Could you drill a small hole, just barely bigger than the igniter leads, and thread them through the hole and attach the clips under the blast plate?

I've always considered the clips and the first few feet of wire as consumable items. They will need to be replaced eventually, depending on age and use. You can mitigate this somewhat by twisting "stand-off leads" onto the igniter wires.