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-   -   Centuri Launch pads and Firing panel... (http://www.oldrocketforum.com/showthread.php?t=7695)

Blushingmule 09-03-2010 11:05 PM

Centuri Launch pads and Firing panel...
 
Hi all,

I have an L1A 100 and 2 L1A 77's and an EP-612 Firing Panel that still works; key, bulb and all. It has the black crinkle paint finish and about 25 feet of wire.

One of the '77's and the '100 are as old as dirt; the other '77 is new in the box.

The used pads need cleaning/restoring. They are all made of some sort of Luan (but
not quite) 3-ply plywood. The larger pad has one honking big blast deflector!

What would be the best way to finish them after cleaning? I'm thinking a neutral stain.

l have to say that Centuri had it sorted out in comparison to the other brands' - 'controller'
wise. It's a tank!
Bob

p.s. yeah, gonna use 'em...

stefanj 09-04-2010 12:48 AM

Hey, could you photo-document these launchers? Scan in the directions, trace the legs, make measurements of the metal parts, etc. ?

I'd love to try re-creating them.

The wooden Centuri launchers were still around when I was getting into the hobby, and my grade school had one of the small ones, but they quickly disappeared. I think the pneumatic servo-launcher made its first appearance in the 1971 catalog which was the first Centuri edition I got my hands on.

The 1971 catalog still listed the fancy metal launch panel, but had introduced a black plastic hand-held model. I had two of these at one point. They were very, very sturdy and futuristic compared to the oval "Astron" launch controller. I sold them to a collector many years back.

Blushingmule 09-04-2010 02:13 AM

Sorry,

At this time no scanner here. However I will make/trace the patterns.

Bob

sandman 09-04-2010 10:51 AM

2 Attachment(s)
Quote:
Originally Posted by Blushingmule
Sorry,

At this time no scanner here. However I will make/trace the patterns.

Bob


I have one of the servo launchers...someplace. It's kind of a cool idea with the pneumatic control.

Sort of like a relay system. but pneumatic.

I can easily reproduce the wooden parts. I even made some of the old Tilt-a-Pad launchers from some old redwood I found.

The only change I made was to increase the disc size to 4" from 3 3/4".

I only had a 4" hole saw. :o

The one in front has a 4" disc(top) and the one in back I sanded down to 3 3/4"

The bigger one looks better...and a lot less work!

dcastle 09-05-2010 09:57 AM

Quote:
Originally Posted by sandman
I have one of the servo launchers...someplace. It's kind of a cool idea with the pneumatic control.

Sort of like a relay system. but pneumatic.

I can easily reproduce the wooden parts. I even made some of the old Tilt-a-Pad launchers from some old redwood I found.

The only change I made was to increase the disc size to 4" from 3 3/4".

I only had a 4" hole saw. :o

The one in front has a 4" disc(top) and the one in back I sanded down to 3 3/4"

The bigger one looks better...and a lot less work!



I had one of the servo launchers when I was a boy...it had been my cousins and then became mine when he got out of rocketry and dropped off a bunch of great stuff.

The launcher was cool and very portable....but...I discovered a fatal flaw in the design one day.

The safety interlock key is on the pad, not on the launch controller (which is a plunger connected to a 10 foot tube that inflates a balloon that pushes the batteries against the contacts to fire the igniter). One fine afternoon in the mid 1970s, I decided to fly my Groove Tube. I set it up on the red servo launcher, hook up the igniters, put the key in then walk back to the launch button and push it...nothing happened. I noticed that the light in the safety key was out so I went and checked the clips and the igniter (which hadn't fired). I then wiggled the key and got it seated better...the light came on and then I heard a hissing sound next to my ear....the rocket was taking off not 3 inches from my head! I ducked quickly and off it went for a successful flight but a rattled flyer.

Here was the problem...when I put the plunger down on the ground to check the pad, it was slightly depressed. When I wiggled the key/light (again, on the launch pad itself), it made contact...and the balloon was, unknown to me, inflated enough to trigger a launch. It was at the ripe age of maybe 13 or so that I realized that if I ever designed a launch control system, the safety interlock key must be placed with the launch button -- not on the launch pad.

I recently picked up one of the Centuri wooden launch pads, still unassembled in the box. The one I have is LIA 77. Outstanding quality parts though the fit is very tight so I haven't worked on putting it together yet. It will also need to be stained and varnished. Not sure when I'll use it but sometime when I'm flying Centuri clones I will.

Doug Sams 09-05-2010 11:12 AM

Quote:
Originally Posted by dcastle
...I realized that if I ever designed a launch control system, the safety interlock key must be placed with the launch button -- not on the launch pad.
Both. You want it on both. When you have a system where there's more than a few steps from controller to pad, the system must be disarm-able from either end. All the HPR stuff I have ever worked with had relayers, and all the relays had safing switches on them so the flyer can set up his rocket without worrying that someone at the rangehead may accidentally arm and fire his rocket.

The only downside to this is the long walk back to the pad to arm it after you've forgotten to :o And after you've waited thru an entire cycle of launching from that set of pads.

Doug

.

Doug Sams 09-05-2010 11:34 AM

Quote:
Originally Posted by dcastle
The launcher was cool and very portable.... but...I discovered a fatal flaw in the design one day.

(snip) the launch controller [is] a plunger connected to a 10 foot tube that inflates a balloon that pushes the batteries against the contacts to fire the igniter.
I've never laid hands on one of these, but based on what I've seen and read over the years, it sounds gimmicky. I suppose that's the basis of the cool factor. But it really does sound Rube Goldberg. It's needlessly complex - I can think of many ways of closing a switch that don't involve balloons and hoses :)

Surely a little heavier wire or a relay could have been used in lieu of the pneumatics at comparable cost. Of course, it wouldn't have been as cool.

Nor as kludgy.

Doug

.

Bill 09-05-2010 11:37 AM

Quote:
Originally Posted by Doug Sams
Both. You want it on both. When you have a system where there's more than a few steps from controller to pad, the system me be disarm-able from either end. All the HPR stuff I have ever worked with had relayers, and all the relays had safing switches on them so the flyer can set up his rocket without worrying that someone at the rangehead may accidentally arm and fire his rocket.

The only downside to this is the long walk back to the pad to arm it after you've forgotten to :o And after you've waited thru an entire cycle of launching from that set of pads.



And in the rare event the relay contacts have fused closed, the relayer units are designed so that the piezo element sounds whenever the leads are energized. Even so, some have developed the habit of touching the clips together and looking for a sparks before hooking up to the igniter. Probably not a bad idea.

The only Centuri launch equipment I still have is the old wooden box with an asbestos pad.


Bill

blackshire 09-05-2010 02:52 PM

Quote:
Originally Posted by Doug Sams
I've never laid hands on one of these, but based on what I've seen and read over the years, it sounds gimmicky. I suppose that's the basis of the cool factor. But it really does sound Rube Goldberg. It's needlessly complex - I can think of many ways of closing a switch that don't involve balloons and hoses :)

Surely a little heavier wire or a relay could have been used in lieu of the pneumatics at comparable cost. Of course, it wouldn't have been as cool.

Nor as kludgy.

Doug

.
Doug, since Centuri designed some of their products (such as the 1340 Sounding Rocket) with industrial and scientific customers in mind, I'm not surprised at the design of the pneumatically-activated Servo Launcher. My guess is that it was originally designed for launching lightning research rockets (the kind that carry fine, ground-connected copper wires to induce lightning strikes at the instrument-equipped launch sites).

Using non-conducting pneumatic tubing instead of copper ignition lead wires decreases the risks of the launching personnel getting struck by the lightning discharges. A more recent lightning rocket experiment series (documented in National Geographic some years ago) utilized Aerotech Arreaux rockets trailing wires into the sky. The experimenters blew into long lengths of surgical rubber tubing to actuate the pneumatic ignition circuit contact mechanisms at the launch pads. (When I expressed interest in replicating these experiments in our back yard in Miami [I likened it to the prophet Elijah calling fire down from heaven], my mother answered with a firm "NO!") :-)

blackshire 09-05-2010 03:09 PM

Quote:
Originally Posted by Bill
-SNIP- The only Centuri launch equipment I still have is the old wooden box with an asbestos pad. -SNIP-
Bill, is it similar to these http://www.ninfinger.org/rockets/ca...65/65cen12.html ? Semroc could bring back that launch pad as a "Retro-Repro" product to be part of a re-issued Centuri "Beginner's Outfit" (with a Micron rocket kit) and/or a re-issued "Rocketeer's Outfit" (with Payloader II and Javelin rocket kits). Using the new resin-locked asbestos sheets, they could even include the asbestos jet deflector for the launch pad! How about it, Carl? :-)


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