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  1. #1
    Join Date
    27th March 2014
    Location
    Pennsylvania
    Posts
    124

    Launch control do you suggest arm and check continuity at every pad or at the LCO

    Could you help me with basic info about club launch control systems?
    Safety...avoiding unexpected firings... overides any other concern of mine.
    Having each rocketeer able to test coninuity and arm at his pad vs. a system that is armed only at the LCO table?

    Appreciate your input and suggestions about systems and info about vendors-manufacturers to purchase launch control systems that are ready to use.
    We run 15 low power and about 8 high power pads

    Last edited by TOM C; 24th August 2015 at 09:24 PM.
    Tom Cohen
    MDRA....Maryland

  2. #2
    Join Date
    6th March 2010
    Location
    Amesbury, MA
    Posts
    1,972
    For both of the clubs I'm in, the arming is controlled at the LCO station. Each pad that has a powered relay has a continuity check button so the flyer can be sure of a good circuit at the pad and newer units are being built that will allow the LCO to check continuity through the relays.

    MMMSC started with a Pratt Hobbies six-pack controller but you would need four of these and lots of extension cords for your 23 pads. For that kind of money, you can have someone build you a great system that could use CAT-5 or some such thing.

    KENN BLADE
    NAR #80160
    CMASS President
    MMMSC Ambassador-at-Large
    NAR S&T Member

  3. #3
    Join Date
    28th May 2013
    Location
    Barstow, California
    Posts
    28
    We have continuity check at the pads and LCO. Arming only at LCO, with audible signals at the pads when that row is armed.

    We are going to a wireless system, which also has continuity at both the pads and LCO, arming only at LCO, and a provision to disarm at the pads...

  4. #4
    Join Date
    9th April 2009
    Location
    Lancaster, Ohio
    Posts
    680
    Wilson FX!!

    Seriously, after doing the whole build your own system to make it what you want and then work on it about half the time, just buy the WilsonFX system. Brad will sell you waht you need now and it is expandable up to full LDRS size and beyond.

    After spending the last three seasons NOT working on a launch system other than replacing a few clips I highly recommend the Wilson system. It has a track record that is unsurpassed in quantity and quality of a digital, expandable system.

    Oh, and the whole thing runs on three wire extension cords.
    Joe Grubb
    TRA 1206 /TAP NAR 78797 / L3
    Tripoli Mid Ohio
    http://www.tripolimidohio.com/
    WVSOAR564 WSR703
    AMA 2610 FORKS

  5. #5
    Join Date
    14th March 2009
    Location
    Ohio
    Posts
    3,116
    I am in the same club as JoeG and the Wilson system is really nice. Highly recommended.
    Zeus-cat
    NAR# 92125 L1
    Total Impulse for 2017: 1,493.8 N/s Flights: 56
    2017: 1/2A:0, A:6, B:11, C:2, D:12, E:4, F:1, G: I have NEVER launched a G motor, H:1, I:1

  6. #6
    Join Date
    5th December 2013
    Location
    MD
    Posts
    6,513
    I think the whole point of having an LCO (besides the humorous comments) is to have control focused at one location by a single, experienced individual. More moving parts = more chances for things to go wrong.

    John S. ---- NAR #96911 ---- TRA #15253 ---- MDRA #067 ---- BARC #028
    L1, 3/15/14: Aerotech Sumo, CTI H133BS
    L2, 6/21/14: Giant Leap Vertical Assault, CTI J240RL
    L3, 3/12/16: MAC Performance Radial Flyer, CTI M1101WH
    Altitude: 13,028', L3 flight; Speed: Mach ???, L3 flight

  7. #7
    Join Date
    25th July 2012
    Location
    Sterling, Illinois
    Posts
    87
    Hello Tom,

    1) No system that allows a pad or a bank of pads to be armed at the pads is safe. Don't go there. That would NOT be safe under any circumstances. Only the LCO should be able to arm a pad at any launch.

    2) Something to reliably do a "Continuity Check" at the pads is a great plus. The larger your club is or at least the larger the launch you are having, the more important this becomes. With larger launches the LCO needs to be able to cycle thru the pads in an efficient manner. Having a "continuity check" at each pad makes this easier to accomplish because the flyer can know (as well as can be known) if he or she has a good igniter in the rocket before they walk back to the flight line. Its much quicker to check at the pad, then if you've got a bad igniter it only takes a very short amount of time to replace it.
    Unfortunately, if the "Continuity Check" is not designed and built correctly, it will be somewhat problematic in the area of safety. There was a very long discussion on the TAP forum a few years ago with whole bunches of "failed" continuity checks that resulted in igniter ignitions. There are some folks who will not use them because of the "chance" of a premature ignition. There is one "commercial" system who's "Continuity check" has never caused a premature ignition: Wilson F/X. But all I know about the other systems is anecdotal.

    3) Cat-5 cables are great for indoor use. Indoor use is what they were designed for. They are simply not rugged enough for long term outdoor use. The cable ends are very vulnerable to damage. Yes, they will work for a while, but long term you are only asking for trouble using them for communication lines between the LCO and the pads.

    4) Some others have mentioned Wilson F/X and I can't agree with them more, but as I'm the Wilson of Wilson F/X I may not be unbiased. Check out the Wilson F/X thread on this forum for lost more information.

    Brad, the Rocket Rev.," Wilson

  8. #8
    Join Date
    7th February 2009
    Location
    Arlington, TX
    Posts
    1,230
    Quote Originally Posted by RocketRev View Post
    1) No system that allows a pad or a bank of pads to be armed at the pads is safe. Don't go there. That would NOT be safe under any circumstances. Only the LCO should be able to arm a pad at any launch.
    I prefer a system that has a pad side safe/arm switch that is in addition to any other safe/arm system. Before connecting the clips to the igniter I make sure that the switch is in the safe position. Now I know that a stupid mistake by the LCO (they do happen) cannot hurt me. At the very least, I will have some distance between myself and the pad when I flip the switch so I can get a running start.

    Another safe option is to carry the key for the safe/arm switch out to the pads and only return it to the LCO when the pads are clear.

  9. #9
    Join Date
    5th December 2013
    Location
    MD
    Posts
    6,513
    Quote Originally Posted by UhClem View Post
    I prefer a system that has a pad side safe/arm switch that is in addition to any other safe/arm system. Before connecting the clips to the igniter I make sure that the switch is in the safe position. Now I know that a stupid mistake by the LCO (they do happen) cannot hurt me. At the very least, I will have some distance between myself and the pad when I flip the switch so I can get a running start.

    Another safe option is to carry the key for the safe/arm switch out to the pads and only return it to the LCO when the pads are clear.
    That's actually a great point that I hadn't thought about. If the pad is hot and you attach the leads, you could burn off your fingers. A disarm at the pad makes sense. And the worse thing that could happen is that you forget to arm it, and then everyone laughs at you.

    John S. ---- NAR #96911 ---- TRA #15253 ---- MDRA #067 ---- BARC #028
    L1, 3/15/14: Aerotech Sumo, CTI H133BS
    L2, 6/21/14: Giant Leap Vertical Assault, CTI J240RL
    L3, 3/12/16: MAC Performance Radial Flyer, CTI M1101WH
    Altitude: 13,028', L3 flight; Speed: Mach ???, L3 flight

  10. #10
    Join Date
    4th May 2010
    Location
    Silicon Valley
    Posts
    620
    Quote Originally Posted by UhClem View Post
    I prefer a system that has a pad side safe/arm switch that is in addition to any other safe/arm system. Before connecting the clips to the igniter I make sure that the switch is in the safe position. Now I know that a stupid mistake by the LCO (they do happen) cannot hurt me. At the very least, I will have some distance between myself and the pad when I flip the switch so I can get a running start.

    Another safe option is to carry the key for the safe/arm switch out to the pads and only return it to the LCO when the pads are clear.
    This is how I designed my hybrid launch control system. I just liked the added safety. I also have a warning buzzer so you don't leave it armed before or after firing.
    Karl Baumheckel
    TRA 11594 L3

  11. #11
    Join Date
    4th May 2010
    Location
    Silicon Valley
    Posts
    620
    3) Cat-5 cables are great for indoor use. Indoor use is what they were designed for. They are simply not rugged enough for long term outdoor use. The cable ends are very vulnerable to damage. Yes, they will work for a while, but long term you are only asking for trouble using them for communication lines between the LCO and the pads.

    Brad, the Rocket Rev.," Wilson[/QUOTE]

    I use stranded Cat 5e network cable and find it completely reliable for my personal hybrid launch control system. My club uses Black Dog Rocketry's custom club system and it uses network cable and I do not know of any problems with it. The difference is the connectors. BDR uses rugged connectors that are great for club use. I use standard RJ45 connectors because they are economical and lock into position. I use a rubber boot to protect the plug from breaking. Another connector to consider would be a mini DIN connector like the old keyboards and mice used. The real nice thing about Cat 5e cable is that it is light weight and packs small. 500 feet of it fits on a spool made for 100 feet of 16/3 extension cord. Here is a video of my Hybrid Launch Control System
    Karl Baumheckel
    TRA 11594 L3

  12. #12
    Join Date
    25th July 2012
    Location
    Sterling, Illinois
    Posts
    87
    Hello Tom,

    I am very sorry that I didn’t follow up on this last year after a couple of people responded to my input against “arming switches” at the pads. But I was just doing a search for Wilson F/X topics here on the TRF and came across this one again. I cannot leave this where it got left because I fear that you might get left with the idea that an “arming switch” at the pad is a good idea. It is not. And here are my reasons why.

    First off, there is a huge difference between a switch for making a pad “safe” for attaching igniter clips to igniters and a switch at the pad that allows the flyer to “arm” the pad. Apparently, there are those who think that a switch to “safe” a pad and an “arming” switch are the same thing. They are NOT. Anybody can add a switch to “safe” a set of igniter leads. All you have to do is put an on/off switch on the positive side of the igniter leads going to the pad and one instantly has a switch to “Safe” the igniter leads. It might be difficult with some systems to tell which is the “positive” side of the igniter leads. But you could use a switch on both sides of the igniter leads if you’re not sure.

    Now let’s talk about “arming” switches as they are a very different kettle of fish from a switch to “safe” a set of igniter leads. The idea of an “arming” switch is to supposedly make a pad completely safe from an accidental igniter firing by the flier, the guy next to the flier, and even from an LCO who doesn’t know what he’s doing. It seems like a great idea. “Let’s keep everybody from accidentally firing igniters when they are at the pads.” It is a great idea except for the simple fact that any analogue circuit capable of “arming” a pad is also going to be capable of firing the pad. And I believe that this is a violation of both the NAR and TRA safety codes. No pad should be armed when there is anyone who is not outside the danger zones delineated in the safe-distance tables of both organizations.

    But let’s talk about “arming” switches at the pads for those who think they are allowed by the safety codes. There are the clubs out there with home-made systems with “arming” switches at the pads that just occasionally launch rockets when the flier “arms” the pad out at the pads. One such club’s system has fired M motors when the flyer armed the pad 30 feet from the rocket. Any system that has the possibility of firing a pad when it is gets “armed” is NOT a safe system. I know of a club with a home-made system that has this very problem. The members of the club were told that if they spent $1800 it would fix the problem. Well they spent the $1800 only to discover that the problem was still there.
    A member of that club sent me the schematics of the club’s then current system and the schematic of the “fix” that would supposedly solve the problem. I emailed him back saying that the “fix” would not solve the problem. Why not? Because the problem was in the design of the system itself and the $1800 solution would not fix that. The member was told that I did not know what I was talking about. Well it is true that somebody didn’t know what they were talking about, but it wasn’t me. The fix failed and that club now owns a vastly more expensive than a Wilson F/X launch system, that still is not safe.

    Now let’s talk about the accidental LCO firing of a pad while the flier is still at the pad. First off, there is no way to stop an LCO from doing something stupid without using a separate second “fire authorization switch” that the LCO does not control. (btw - Wilson F/X has just such a switch available for clubs that want a second person “fire” authorization) But let’s get back to the LCO with a problem. Any launch system safe enough to use ought to have some kind of WARNING at the pads that a particular bank of pads has been “armed” accidentally or on purpose. There should be at least a screeching buzzer that warns people of the “arming” of a bank of pads. That way, if they hear the screeching buzzer they know to get away from the pads A.S.A.P.

    Secondly, it is true that an LCO might accidently leave a bank of pads armed and a pad “selected.” But if the precaution of the screeching buzzer for an “armed” bank of pads was already in place, the flyers would know it BEFORE they actually approached the pads that were still armed. If the “armed” bank of pads warning is not automatically in place, then it is NOT a safe system. An “armed” pad is a dangerous pad for the very reason that it is “armed.” An “armed” pad can be fired. And according to the simplest interpretation of both the NAR and TRA safety codes, no pad should be armed if there is anybody closer than the minimum safe distance table specifies. So it is my belief that any system that can be “armed” by the flier is not only unsafe, but is in violation of both the NAR and TRA Safety Codes. The solution to an unsafe LCO cannot be to add another layer of un-safe technology. Adding another layer of problems to an existing problem is not a solution to the problem.

    I know that these are just my opinions, but as somebody who started building analogue club sized launch systems back in the late ’60’s and into the ‘80’s, I know a thing or two about club launch systems. As soon as I got into high power rocketry back in 1991, I started studying the then current technology of club launch systems. I went all over this country flying with dozens of high power clubs and I studied their launch systems. I repeatedly saw the same problems: sticking relays from unregulated relay activation voltage/amperage circuitry; those same sticking relays firing igniters when the igniter leads were hooked up; a pair of wires from every pad all the way back to the Launch controller on the LCO table causing massive amounts of wire on the ground; CAT5 cables used to try to fix this problem but failing in long term usage; mostly poorly designed continuity testing circuits at the pads that were not safe; rats nests of wiring inside launch controllers that made building difficult and repairs even harder; accidental firing of pads when launch controller switches were changed between different banks of pads from sparking rotary switches; and lastly, far too many clubs that had to spend countless hours repairing their club launch systems between launches just to keep them operating even at a poor level of quality. Every single one of those clubs was doing its best utilizing basic analogue technology from the 1980’s. It mostly works ok for a while, but it is simply obsolete tech.

    This is exactly why back in 1994, Wilson F/X technology was first created: to fix all of those problems. And we continue to add innovative solutions to the problems and demands of today’s rocketeers and rocket clubs. I’m not here to pick on anybody, but you need to know that not everything you read, even here on the TRF, is well reasoned or a wise way of doing things.

    Brad
    TRA #01630 L-3 TAP
    NAR #70929 L-3 L3CC


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