Launcher and Launch Area Technical Support Truck

Here is my LATS Truck, or Launch Area Technical Support Truck.  When the launch area is far away from the parking area, I spend a lot of time walking back-and-forth from the launch area to the car, so to save time and my legs I came up with this contraption.  This allows me to bring all my 'stuff' to the launch area in one trip, and allows me to work on the rockets without having to sit down on the grass and loose small items in the turf.

It is made from a steel utility cart, and has two wooden shelves to hold two toolboxes.  The lower toolbox has tools and various supplies for launching, such as masking tape, binoculars, spare fishing clips, streamers, wadding etc.  The upper toolbox holds plastic storage boxes with the various one-use motors, ignitors and more wadding.

The seperate toolboxes allows me to load them in the car seperately, so loading in the cart is not too heavy. The cart also has hooks to help carry the launch tripod, launch controller, cameras, clipboards and other assorted stuff.  The back of the cart has a fold-out table surface. This surface is framed to prevent small pens, motors, etc from rolling off the edges. It also has a nice, soft cork surface.

In the picture, I have my Alpha and X-Ray out for launching, with a box of wadding, Altimeter Two, masking tape, scotch tape, pliers, sandpaper. This makes it easier to prep rockets while standing, and I don't have to kneel down in the grass and work on often damp or muddy conditions.  It is a real time-saver and knee-saver!

Here are a few closer views of the truck.  This lower tool box has a lot of tools in three drawers and a few spare supplies for rocket launching. It is heavy and should remain in the truck to provide a heavy base for the table when it is extended. I also pack my altimeters, GPS and binoculars in there.

This is the upper toolbox. I use it mostly to store my motors. There are 18 little plastic boxes in seperate compartments in the bottom that hold an assortment of 13, 18 and 24 mm motors.  Above them are four more boxes that hold my most often used motors,  B6-4, C6-5, and D12s.  Of course all boxes are clearly labeled. When not actively flying, this box goes inside and remains in a cool, dry place.  I don't want any of these motors going bad in storage.

You may also notice in this picture that there are hooks on the one side to carry and/or hold camera bags, binoculars, jackets etc.  The large aluminum tube attached to this side holds 4-foot lengths of my three launch rods.  This keeps them safe from being bent and keeps them from taking out an eye or two.

Next I would like to show you my field-deployable rocket rack.  It is designed to hook on to the front of the cart shown above so I can carry all my rockets out to the launch zone with the cart.

I included two features in this design. First, notice that it is "flow-thru", in that reasonable non-hurricane winds will not tip it over and destroy the rockets.  It is also light weight.  All the arms that hold the rockets are padded with cheap pipe insulation.  I used four long bungees (normally used for higher-power shock cords) to hold the rockets tightly but gently to the rack.  While this worked great, I didn't design it to protect the rockets in the rain.  Sure enough, on day one of trying it out, it started sprinkling, so I had to throw a tarp over the whole thing, making it vulnerable to wind.  Oh well, I didn't intend to leave these out in the rain anyways!

Here is the view from behind the rack.  You can see the two posts on hinges that let it lean far back at an angle.  I didn't take any chances with that angle, I made sure it leaned FAR back so it won't tip over from heavy rockets.  You may also see the pipe insulation attached to the rack with staples on the sides of the wood.  You may also see one of the four white bungee cords swung over the back out of the way and not being used at this time.  What is harder to see here is that I used four steel wire sets going from corner-to-corner to keep the front and back frames square. I used stranded steel wire for hanging picture frames.  As it turned out, it was fairly rigid without the wires, but I had them so I put them on anyways.  There are also two strings holding the front and rear sections so they can't be spread too far apart and colapse backwards.

Closeup view showing how the bungees are attached. Simple really. Notice the insulation/padding continues up the wood backing to provide protection to the rocket from the rear also.

 

****

This is what my launch system looks like from the inside. It is a fire-resistant box (meant for papers, cash etc.) that houses two 7.2-volt NiCd batteries, so there is a very short path between the power source and the ignitors. This is to minimize the voltage drop across long wires and allow for maximum power being delivered to the igniter.
This box also has a mechanisim to adjust the angle of the launch rod by turning a set of knobs, instead of having to loosen a screw and re-tighten it to tweak the launch angle.
For safety, it has three seperate relays which must all be activated to ignite a motor. This makes it very fail-safe because even if one relay welds itself on and is stuck, the other two will still prevent a ignition.  A long, 25-foot CAT-5 cable connects this box to the control box as shown below.

This controller is mounted on a 3-foot aluminum rod on the left side.  The rod is stuck into the ground and holds this at a comfortable working level.  The large meter on the unit monitors the battery voltage.  To launch, all three red buttons must be pressed and held, and they are spaced apart to require two hands to press all three. Each button enables one of the three relays in the launcher.  Also, the safety key must be inserted, and the arming switch must be on/up.  The small OK LED is used to verify ignitor continuity.






Here we see the launcher deployed in the field.  The entire system is inside the box and remote control.  Both of these parts are held up on a lightweight aluminum structure.  This saves both the back and knees, and in the case of the launch rod, may save an eye as well by being well above eye level for all but the freakishly tall, somebody on stilts or possibly a giraffe.

This closer view of the business end of the launcher shows the mechanisim to hold the rocket up above the blast deflector.  No more burned clothespins or balancing motor casings. It can be adjusted in height and also front-to-back to accomodate nearly any rocket.

The blast deflector is angled to direct the blast to the rear, which somewhat reduces the cloud of smoke obscuring the launch for closeup photography.  Notice too that the ignition wire clips are made using 14 guage solid copper.  This allows them to be bent into position to grasp the igniter wires without pulling them down under the weight of the wires.  These wires are not insulated, so there is no worry about melting insulation.

The only concern here is making sure not to let the two wires short each other or short onto the blast deflector, but that is fairly easy to do.  These clips have held up for dozens and dozens of launches and have not needed replacement yet.  If they do prove to degrade beyond use, I made several sets of spares that can be plugged into the banana jacks in about a second or two.

This launcher is able to use 1/8", 3/16", and 1/4" launch rods. Shown here is the 3/16".

Seen here (above), I added clear white labels to pretty-up the controller a bit, as the previous painted legend was getting a bit ugly.

OK - this is the normal continuity indicator.  It is an LED, so it draws very little current and will absolutely not be enough to heat a igniter.

ARM / SAFE - This basic switch will prevent the igniter from getting current.

CHECK - This button is pressed and held to see if continuity is good. If not pressed, zero current will flow through the igniter, not even a little bit of LED continuity current.  Also, this button must be held down by the left hand to allow ingition, since it completes the ARM current and allows the first of three redundant relays to be energized.

SIREN - This is a second arming circuit that is wired in with the safety key.  When this is pressed (normally at about T-2 seconds), it will energize the second of three redundant relays if the key is inserted.  It is named siren because my intention was to add a mechanical motor/siren to the launcher that will also sound when this second circuit is energized. (I didn't add it yet though, I had it on my workbench but I seemed to have lost it!)

KEY - This key needs to be inserted to allow the second arming circuit to be energized.  When it is removed, the circuit is open and launching can not be done.

LAUNCH BUTTON - This has a silver legend.  Assuming the ARM/CHECK circuit is energized, and the SIREN/KEY circuit is also energized, this button will energize the third of the three relays, completing a circuit from the battery to the igniter.  This is pressed at launch time T-0.  This button is placed on the right side, and is intended to be pressed with the right hand.  The other two buttons are purposefully placed on the left, away from this button, and need to be pressed by the left hand.  This is to prevent a inadvertent bump of  one of these buttons from likely hitting all three buttons.

BAT CHECK - This switch is flipped on to make sure there are no flying bats in the area before launch.  At other times, it switches battery voltage to the center volt meter to indicate the health of the two 7.2 volt batteries in series.  With normally fully charged batteries, this will deflect fully and read 15 volts (ok, 14.4 volts to be exact).  The switch is there to avoid having the meter, which does draw some current, from draining the batteries if left connected for extended periods.

In addition to having the ARM switch on and the KEY inserted and all three red buttons pressed & held, the main launch box which contains the batteries also has its own power on/off switch.  This is to make sure under any circumstance the batteries will not be drained, and is a handy backup swtich when one is at the launcher and about to connect the igniter.  A few times I am unsure and ask myself, "Did I leave the key in and the arm switch on again?"  Instead of having to check, I can just flip this switch to off and be sure I will not ignite the motor as soon as the second clip is attached.

The End.