Multi-launch LPR controller re-build

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Oldschool77

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Hello all! I recently was gifted a 12v controller(40+ yrs old) from my hi-school days. The external wires are shot and much to short(~15ft!?) for NAR/TRA compliance. I have looked on the NAR site to no avail as to what the required distances are for operator to pad. The box has yet to be opened , but I suspect that wiring will need replaced there as well.
The plan is to mount that box to another that is equipped with a buss bar & RCA type jacks for ease of tear-down/setup. The help I need is what are the distances for A-D, E, F & wire ga. recomendations. Also any other ideas, oh and it will have a safety key!
 
They could have, I am working from memory and coyld be wrong. Our club uses A-C at 15' and D-G at 50' . Mainly the D and Es are because those catos are not cool at close range, not that we get many D catos, but we get 1-2 E catos every launch.
 
15 and 30 is still it.

https://www.nar.org/safety-information/model-rocket-safety-code/

MODEL ROCKET SAFETY CODE
EFFECTIVE AUGUST 2012

...

5. Launch Safety. I will use a countdown before launch, and will ensure that everyone is paying attention and is a safe distance of at least 15 feet away when I launch rockets with D motors or smaller, and 30 feet when I launch larger rockets. If I am uncertain about the safety or stability of an untested rocket, I will check the stability before flight and will fly it only after warning spectators and clearing them away to a safe distance. When conducting a simultaneous launch of more than ten rockets I will observe a safe distance of 1.5 times the maximum expected altitude of any launched rocket.



NFPA 1122 2018 Edition

4.14 Spectator Distances.

4.14.1 All persons shall remain at least 4.6m (15ft) from the model rocket during
ignition of a model rocket motor with an installed total impulse of 30 N-sec
(6.7lb-sec) or less.

4.14.2 All persons shall remain at least 9m (30ft) from the model rocket during
ignition of a model rocket motor with an installed total impulse of more than 30 N-sec
(6.7lb-sec).



Those are minimums, feel free to go longer for your application. I'll leave it to the EEs to recommend a wire gauge.
 
We use standard 50 ft. extension cords to run out to each pad. Easy plug-in/unplug and keeps all the LPR/MPR beyond the required minimums.
Thats what we do as well for out LPR, 25' extension cords from our Pratt 6 pad Launch Controllers, the LPR pads end up at about 20'. Our MPR and HPR are custom relay types that have a CAT5 cable as the wire goibg from the Controller to each 4 pad box.
 
Thats what we do as well for out LPR, 25' extension cords from our Pratt 6 pad Launch Controllers, the LPR pads end up at about 20'. Our MPR and HPR are custom relay types that have a CAT5 cable as the wire goibg from the Controller to each 4 pad box.

We have the Pratt 6 boxes too and use the 50 ft. cords with them. We had a 5 rod LPR rack and a 1/4" rod on a 6th pad shared with a 1010 rail. Since so many of the TARC teams are using rails now, we built a new controller box that can handle 8 pads and we now use the 5 rod rack, with a 1/4" pad and two 1010 rails. We zip tied the eight 50 ft extension cords together to make setup quicker.
 
Thanks all, extension cords can be inexpensive if purchased through the right sources.
 
Every time I see someone who has a vacuum cleaner in the garbage I stop and cut the cord off. It's almost like a free 20-30' extension cord. Eventually I will do something with all of them.
 
Hello Tony,

Now that we have the safe distances down, its time to get to work on the controller itself. If you want some real help, I would suggest opening up the box and taking pictures to post here. Otherwise we'll be mostly flailing around and not accomplishing much.

You never mentioned how many pads or banks of pads this thing controls. Good thing to know for a start considering the more pads that it controls, the more complex the internal wiring will be.

Did it have any kind of working continuity checking capabilities?

Several people have mentioned their commercial control systems. I could mention Wilson F/X Digital Control Systems which have been around since 1994. I know that's only 24 years, but I built my first launch system over 50 years ago and my first 8-pad system 48 years ago. I've built about a dozen low power analogue club systems for A thru G motors. And I've repaired and rebuilt several of them over the years. So I know a thing or two about what you're probably looking at when you open the box.

But like I said, pictures will help more than anything.

Just some things to think about:
1) all of the switches may/probably also need replacing
2) All the internal wiring probably needs replacing
3) all solder joints will need replacing
4) what condition is the enclosure in and what's the material from which its made?
a) rusty
b) cracked plastic
c) splintered wood
d) cardboard with holes
e) good condition?
f) steel, aluminum, plastic, fiberglass, ????????
5) are there any indicator lights, if yes, do they work? Can the burnt bulbs be replaced?
6) nostalgia is great, but is this thing worth the time and money you're going to put into it?

You might want to rethink the RCA jacks for igniter lead connections. They are inexpensive, but that's because they're not particularly robust. I wouldn't want to put this much work into something that's not going to last. I would suggest going with Anderson Power Pole connectors from Powerwerx: the pp15 in the paired red/black housing works great for the #16 AWG wire and are more than adequate for even 50 foot leads. And they have a panel mount designed for installing in a panel. Could make identifying igniter lead connections on the controller a lot easier. I get mine from Powerwerx and I use them for power connections and lead connections on some of my Wilson F/X components.

And you mentioned that you need an on/off key switch. Do you have one? If not, a rugged one is available from Digikey, part number CKC8039-ND

Also bulk alligator clips, 290-1942-ND for the 10 amp 2" long, barreled crimp on ones which work well with #16 AWG wire

There are also smaller alligator clips 314-1010-ND which are for up to 5 amps and about 1 inch long and work well with #18 AWG wire

Go to the digikey web site look up "test and measurement" products, then scroll down to test clips. Lots of different varieties and price ranges are available including solid copper! Bulk pricing available.

Look up the prices of the switches and everything else you'll need. Consider how much time this is going to take, then consider very carefully if this is a project that you really want to do.

If its a four to eight pad system, I'd probably go for it. If its larger? Well, things get expensive real quick.

I'm not here to discourage you, but I don't want you to start without considering the real probable costs that you're looking at.

Just some thoughts.

Let's see some pictures so that we all can be more helpful.

Brad, the "Rocket Rev.," Wilson
 
I could mention Wilson F/X Digital Control Systems which have been around since 1994. I know that's only 24 years, but I built my first launch system over 50 years ago and my first 8-pad system 48 years ago. I've built about a dozen low power analogue club systems for A thru G motors. And I've repaired and rebuilt several of them over the years.

Brad, you don't look that old!!!

From the Ether...
 
Its a good news bad news thing.

Good news is: supposedly you're only as old as you feel......

Bad news is: that I've been feeling stuff for over 62 years now!

Sure I don't feel old, but I'm definitely not 26 years old anymore except when my dyslexia is acting up (yes its real and its nasty. Imagine taking Greek and Hebrew with it). Thank God for spell check or I'd be accused of having put my trust in Dog.

Brad (the Bard: keeper of ancient cultural traditions - my vocation and my day-job)
"Rocket Rev.," .... Hey, I didn't pick it. Blame the guys at Tripoli Wisconsin!
Wilson - family name going back at least 14 generations.
- I'm just glad I'm not Ralph Wilson the 3rd: thanks dad......

So yeah, I've earned my grey hairs. Every single one of them, even if there are fewer of them than there used to be.

Remember, There's no such thing as a free LAUNCH......

Brad
 
Last edited:
Its a good news bad news thing.

Good news is: supposedly you're only as old as you feel......

Bad news is: that I've been feeling stuff for over 62 years now!

Sure I don't feel old, but I'm definitely not 26 years old anymore except when my dyslexia is acting up (yes its real and its nasty. Imagine taking Greek and Hebrew with it). Thank God for spell check or I'd be accused of having put my trust in Dog.

Brad (the Bard: keeper of ancient cultural traditions - my vocation and my day-job)
"Rocket Rev.," .... Hey, I didn't pick it. Blame the guys at Tripoli Wisconsin!
Wilson - family name going back at least 14 generations.
- I'm just glad I'm not Ralph Wilson the 3rd: thanks dad......

So yeah, I've earned my grey hairs. Every single one of them, even if there are fewer of them than there used to be.

Remember, There's no such thing as a free LAUNCH......

Brad
Hey, Mister Wilson........
 
...
I would suggest going with Anderson Power Pole connectors from Powerwerx: the pp15 in the paired red/black housing works great for the #16 AWG wire and are more than adequate for even 50 foot leads. And they have a panel mount designed for installing in a panel. Could make identifying igniter lead connections on the controller a lot easier. I get mine from Powerwerx and I use them for power connections and lead connections on some of my Wilson F/X components.
.........

Go to the digikey web site look up "test and measurement" products, then scroll down to test clips. Lots of different varieties and price ranges are available including solid copper! Bulk pricing available.

I love Anderson Power Poles and have been using them for over 35 years - first using the pp30 version (which fit in the same housings) as the main connectors for electric powered RC airplane power connectors. I have used them on some launch equipment I have built for myself and small groups and they work very well for any kind of power connection - input to the controller, clip leads, controller to pad leads, all of it. The wide variety of colors the housings come in can really help keep straight which wire does what as well.

Lots of other great recommendations from the Rocket Rev but I have one caution about test clips and Digi-Key: The Mueller “solid copper” flat jawed clips that many of us remember from the early days are not what they used to be. Current ones are MUCH thinner metal to the point where the jaws bend just about every time you use them. I have some old ones on original old Estes GSE, and they are MUCH more robust than the ones you can buy now. So I’d pass on them (sadly).
 
6) nostalgia is great, but is this thing worth the time and money you're going to put into it?

If its a four to eight pad system, I'd probably go for it. If its larger? Well, things get expensive real quick.

I'm not here to discourage you, but I don't want you to start without considering the real probable costs that you're looking at.

Just some thoughts.

Let's see some pictures so that we all can be more helpful.

Brad, the "Rocket Rev.," Wilson

+1 on this Brad

Great advice. Having just built a LPR controller for the club for 8 pads, I know we spent close to $200 for the whole controller. That didn't include the wires to the pads or the clips...

Rebuilding an existing box might save on the cost of the box, but getting solid parts that will last can be costly.
 
A lot of responses here. This is a for a 10 bank system, to answer some Q's. HD metal box. There is a power toggle switch-broken, will be replaced for master/pwr. A keyed master arm switch will be added. Luckily I know someone who can help me with the rewiring needed for this. Push button launch-usable. 2 position(dtsp?) off-continuity/arm toggles, 1 per bank. This was built for simplicity in the 70's folks. The 12v input wire has been cut off, a cheap easy fix. So It's obvious i haven't powered it yet to check the bulbs and toggle continuity. Everything inside is good. The external lead wires need replacing and most of the gator clips are usable w/ a little wire brush cleaning.

The Anderson power poles look good, especially when coupled with the Power splitter source strip. $50-$60 on a very quick search. Which would be about the same price as 5 110v sockets and extension cords. But I will still need lead wire for the former. Or I might just add a buss-bar to back of the controller and use split terminal connectors on the lead wire. Yah I'll need a screwdriver and extra connectors, it will work just as well but not as fancy.
 
Hey Tony,

Here's a suggestion, rather than replace the master power toggle switch with another toggle switch, why not just replace it with a key switch now rather than add it later?

Just a thought.

Brad
 
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