Launchers & Controllers

Most 12v Gel Cells will work well. A 6v lantern battery will work too but it is lacking for many high power ignitors.

Many use 12V car or motorcycle batteries. They last forever and can produce enough current to light clusters easily. Smaller batteries will work, but they either die quickly, or don't produce enough current to reliably ignight clusters...or both, in the case of the Estes launch controller. (4 AA batteries)

Simple answer is "it depends"!

For BP, the Estes controller used 6 volts (4xAA), and the quest controller uses a 9 volt battery.

Now if you plan on launching any APCP motors, 12v would be needed,

You also may want to use longer wire than the standard controllers for BP do. It's only about 15' long. When I launch smaller stuff with kids, I usually use a 50' cable, but only extend it 25-30 ft. I find standing back a bit gives a better view of the flight.

Also, don't forget to add a safety interlock on the controller (key switch for example).

There are (or were a few years back) some plans on ROL for various types of launch controllers.

Although I appreciated all of the replies / posts....this is probably the most honest.

Thanks Woody!

You could scratch-build launch controller and use a 7.2V hobby batt pack for a power source, and enclosure and switches from Radio Shack. Small, lightweight, and simple. A single 1700 MAh pack will light a 2 or 3 Estes motor cluster just fine. I recommend you invest a few bucks in to buying/building a nice controller. You'll be glad you did!

Here is a fantastic, inexpensive, scratch-built launch pad:

Ironically, when I was building mine....I perused the aisles at my local Home Depot; looking for ideas. This was *before* I saw this article. And

*my* pad is about 90% the same as *this* pad!

:o)

2 AA cells CAN ignite a Solar ignitor. They can easilly fire some of the more sensitive ignitors. But for general use and reliability, 12v in the form of a gell cell, car / motorcycle / tractor battery, or RC nicad packs is recommended.

Don't forget the WIRE, which is the other common weak point. Questes uses very lightweight wire. Too light weight. At a minimum use 18ga lamp cord. But the cheapest wire you'll be able to find is from the orange extension cords. If ou don't have an old one ready to toss that you can salvage, a 25' cord is prefect for MR, and 50 lets you launch E-F-G as well. And the orange wire is MUCh more visible on the ground than the black, brown, or grey wire usually used.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

I've built a nifty (IMHO) little launch controller that uses a battery pack from an electric powered plane. It is a little on the expensive side for the packs (about $30), but the 1700 mAH sub-C cells will dump current like crazy - my brushless motor will pull a steady 25 or 30 amps. It is an 8 cell pack with a nominal voltage of 9.6v, but is probably peaking at about

11V even after 10 or 12 launches. The charger is the expensive part, but I already had that for my planes. I've use that system to light up to 3 Solar ignitors just about instantly (and burn right through the little nicrome bridge) and Copperheads for E18's with just a slight delay.

The battery packs are hooked to the controller with Anderson Power Poles, and I have a set of car battery type clamps that I can use as well.

The wire to the pad is a 35 foot vacuum cleaner cord. Two conductor, fairly heavy gauge. It is connected to a 25A automotive relay that pulls in when you hit the GO button. The whole thing is protected by a 30A fuse, just in case of a short on the leads.

Thirty five feet is a little long for the A-D black powder, but can feel a little short for even the E powered composites.

The continuity test button has about 500K ohms to a transister that drives an LED. I get continuity by holding both leads in the same hand. I did this in case I ever used a low current ignitor - this should not allow more than a milliamp or two. A bit of overkill but it was a fun as a project.

The power to the relay coil is broken until the headphone jack safety key is inserted (and the GO button is pressed, of course). I used a simple two conductor jack and I shorted the leads under the plug cover. Loop a piece of string though the loop between the plug leads and you can hang the key around your neck as you walk your rocket to the pad.

My pads are the little Estes and a Mantis. I'll move up if/when I decide to make a multi connected controller and need a multi rod system. Anything that is too big for those pads is too big for me not to be at a club launch anyway.

I've used these a couple times. HIGHLY recommended. The little tiny ones I've seen in the RC market take at least 15A; the industrial ones I've scrounged from UPS systems 100-200a or more!

If you've got a relay and battery at the pad, the cord back to the controller can be very light. I use phone or similar type cords.

IMHO a fuse is not necessary. You ARE creating a direct short across the battery. I saw one fused launcher, and he blew a fuse every time he tried to fire his rocket.

I like hte buzzer at the pad relay box. Instant audio feedback as I connect the clips. Important at my age when your eyes no longer focus within arms length.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Don't you hate it when Your arms are to short?

I extended my arms by getting glasses.

Man, that's gotta be way cheaper than arm lengthening surgery!

A tip for you big spenders - If you don't mind how they look, you can get them for a buck at the dollar store.

I wear Flexon frames. THis is no bs - I stepped on them and they didn't break. The lenses didn't do as well but I have a pair that's aver 5 years old and another that are about two years old. I just get the lenses replaced once in a while. If you are likely to loose them, they aren't for you. ($$$)

Those wouldn't be 'BC' frames now would they?

:)

Ted Novak TRA#5512 IEAS#75

No - they still sell them and they are not old people style.

The prescription sunglasses I wanted for rocket flying would have cost almost $400! So I'm still wearing my old non-prescription RayBans on the field.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!