Newbie questions

[noahnott]

Since when could libraries do that!? Hmm, they didnt do that in Nepal =P ...i could also check my school library, but i doubt they will have it.

Ill see if I can get my hands on a copy one way or another.

*edit* I just launched my rocket that i made. Rock sim estimated it going 1400ft, ...i dont know what a rocket looks like at that height, but i do know it went higher than some cheapy rockets i bought at the store which said they go over 1200ft. This would be my first rocket that actually works great! Didnt wobble at all, but i bet if there is some wind it will weather cock like no other.

 

[f16fan12]

Better yet, just buy the handbook.
There aren't really many books on model rocketry that you'll find in libraries or book stores. Apogee and some other online companies have made books worth checking out, and Sport Rocketry is a pretty good magazine that you'll probably enjoy reading as a rocketeer. I did find this one book at Borders (I think) though: Rocket Science: Rocket Science in the Second Millenium. It's by Alfred J. Zaehringer who's supposed to be some kind of established rocket scientist. Not specifically on model rocketry, but what the hey, rocket good.

 

[jflis]

Originally posted by noahnott
Since when could libraries do that!?

well...

...always...

 

[noahnott]

haha, shows how much i know

 

[noahnott]

Yep, another question. I was thinking about launching two rockets at once, or launching a cluster rocket, and i dont think my little starter thing i have will do the trick. So...that leaves me with building a launch controller (is that what there called?).

So what i understand is that the starter sends down a lot of amps to the igniter when you press the launch button thus launching it. This is basically how it works? If so then....

It would be possible to construct a CHEAP circuit that is capable of launching multiple rockets. I searched this on google and got this one guy who gave some diagrams, but he used a ton of relays and other stuff which i thought was pointless.

Yes im serious about this...now continuing...

Just to make sure i know if im headed in the right direction...the lightbulb usually acts like a resistor and when you push the launch button the electricity bypasses it going into the wire which has less resistance. This creates more amps and launches the rocket as far as I know? So if this is a case, i can scrap the relays and other pointless stuff and just use some wires, a few switches, a few light bulbs, and a 9 volt battery to construct a SIMPLE CHEAP multiple launch pad? Just making sure this sounds right b4 i actually make something =D

*edit* will the 9volt batt be enough? Or will i need a second or just use a 12 volt?

I was looking at this guys diagrams and couldent figure out what the relays were for...or the fuses...Help here?

Thanks,
Noah

 

[cjl]

Use 12v

As for the circuit, keep in mind the following requirements:

Must have some kind of removeable safety interlock (safety key)

Launch switch must be momentary

Those are the basic requirements. A continuity testing circuit is nice too.

 

[noahnott]

Yah i have kept those things in mind.

Is there a way i dont have to carry around a 12v battery, i would much prefer a light 9v =D since im the only person using it.

Thanks a lot. At least i know im not making some pile of junk.

 

[m85476585]

A 9.6 volt NiCd battery for RC cars makes a great launcher battery, and it can launch more than 2 Estes engines at once (I have only tried 2).

I have something like this:
<img src="https://www.matt13.com/rockets/images/launch_controller.jpg" />

The LED and buzzer serve as the current limiting for the continuity check. I used a 12 volt LED (built-in resistor) and a 12 volt buzzer from Radioshack (both work on 9.6v). You have to hold both the test and launch buttons to launch.

 

[f16fan12]

Ok, I'm no expert on this, but I've made a launch controller utilizing a 12 V battery and a relay. 12 V is what you want...you can get a cheap one. Gel cells are best. You can recharge them too...I bought a recharger at walmart for maybe 17 bucks.

The relay to me just looks like it organized everything. I'm pretty sure it also amplifies the current that actually goes to the igniters. But what I mean about organizing is that there are two contacts being used for the wires out to the igniter, and then two others. One of these two others comes from the switch and safety key, and the other one plugs into the battery. When they're all plugged into the relay, the relay completes the circuit and allows current to pass.

Someone else really needs to explain this better.

https://www.narhams.org/tech/006-Clustering.pdf
https://www.info-central.org/support_relaylauncher.shtml
https://www.esteseducator.com/Pdf_files/1976clas.pdf
https://www.dars.org/jimz/manuals/tir-52.pdf
https://www.va2ton.7p.com/launch.htm
https://www.wilhelm-aerospace.org/WAEC/Projects/12v-big.jpeg
https://www.vatsaas.org/rtv/lessons/clusters.aspx

Those are all the links I looked at when I was looking to make my own. Clubs are excellent though for clusters. Clubs and igniters with long leads that can be easily twisted together...

 

[noahnott]

Thanks, the picture helped a lot right there.

Forgot to tell you, when trying to figure out how my starter works, i broke the volt meter ...hey it put out more amps that i thought.

As for the 9.6v batts, i got a few of those laying around

*edit* Hmm, never thought the relays that way ...

Thanks

 

[m85476585]

A relay doesn't amplify current, it just allows a lot of current to flow after being triggered by a little current. I don't think you need a relay or a 12 volt battery if you are just launching 1-3 Estes engines at a time. Any more or any mid-power motors and I would say you do need 12V.

Your voltmeter might just need a new fuse if you are lucky. Go to Radioshack and see if they can help you.

 

[m85476585]

A relay controller can quickly get complex. I designed one that would have a battery near the pad with continuity check and firing from a remote box connected by only a 2 conductor cable (it's cheap), parallel relays, and stuck contact detection near the pad. I never built it because I have no need for it.

 

[noahnott]

So no 12v battery...flip flopping back and forth haha. Nor any relays...thats also good (i prefer to stay away from them).

Ill see if i have any time to make this thing, er, and buy the stuff.

 

[cjl]

I would use 12v. This gives mid power capability for later on. It is cheap, and not that heavy. A good 7Ah battery can be had for $15 or less, and will last you forever.

 

[noahnott]

I dont know about me touching a midpower motor. I can always build another launch controller if i need it; im trying to stay away from heavy batteries.

 

[cjl]

Hahaha...


What - are you trudging out to the middle of the swamplands to launch rockets?

Something like this is fine, and it only weighs a bit. Heavier than AA's, yes, but easily manageable.

 

[RandyM]

Here is a really nice and easy circuit that I used.

https://www.info-central.org/index.cgi?support

Click on build a launcher from that page. I built mine with a few mods, but it is basicly the same thing. I used a car jumper and built it into that. It works great and was only $20. It gives you a really big and powerfull battery ( after all, it can start a car) and also a built in charger. A good gel cel charger will run you about that much. I bought most of the parts from bgmicro. https://www.bgmicro.com

 

[RandyM]

The pic didn't attach.

 

[noahnott]

For one, im going to look at that starter once i finish this essay (which im doing at this very moment) but i did glance at it for a bit.

About the swamps, no i dont go that far away from the car. However I am pretty weak haha.

 

[noahnott]

Oh, another useful bit of info i will need to know is what does it take (power wise) to ignite a starter of an estes motor?

 

[m85476585]

The design I posted above will work with any battery from 9-14 volts (or any voltage you want if you find an LED and buzzer that will work at that voltage), so if you ever decide you need more power than a 9.6V battery you could just replace it with a 12 volt one. At Radioshack they sell connectors that can connect to a 9.6V battery. I put one of those on the controller, and if I ever get a 12 volt battery I would put the other one (a matching pair is included in a pack) on the 12V battery. It would probably be fine without relays, but higher current (if you launch many motors at once or some mid/high power motors) might be hard on the switches. I think the ones I found are rated for 5A@12V (more is usually OK for short times).

 

[ben]

Noah, you can use the one from CJL's link its only 5lbs! I think even you can lift that that is prolly lighter than your range box I would really go with 12V, trust me, once you use take the jump and gt a D pr E off ther internet you eill end up with an RMS case within weeks

thanx, Ben

 

[noahnott]

hmm hmm...5lbs, thats lighter than my computer! lol, (my laptop is the size of a dumb truck)

 

[ben]

SSSSEEEEE!!!! I think I will build a launch controller (12V) I NEED (yeah ) one. I would love to make a RF (radio frequency) controller to launch my pad and my clubs HPR pad

thanx, Ben

 

[noahnott]

Making a rc one is going a little too far for me, but just for curiosity's sake, how would that work. Well the NAR says you need to have a the stuff with the switches going on, but you cant really do that with an RC controller can you?

*edit* well actually you could...but well, hmm...

Somebody else in your area is flying on the same frequency and your rocket launches =P that wouldent be the best thing that could happen.

 

[noahnott]

One more thing way off topic. How much does a rocket hurt if it goes up, does a loop and comes right at you? Say a C6-5 styrofoam tip (coated w/ elmers) about 50g. Leave a bump hard or a "ouch...ok lets try the other rocket"

one of mine lawn darted once, um, and was wondering if i was the ground and the ground was me.

-Noah

 

[m85476585]

Styrofoam probably isn't too bad, but I've never been hit by rocket. Put a C6 in it and have someone throw it at you and see what happens. A lawndart might hurt more because it would be moving faster.

You really wouldn't want to be hit by a lawndarting HPR rocket. They can do some serious damage, like drive themselves into the ground so the rocket is completely level with the ground.

This was a 12' rocket:
https://albums.photo.epson.com/j/ViewPhoto?u=4283243&a=32146720&p=74035029

It is better to build rockets that you can be confident in because they will probably be safer. You could get a longer launch cable if you don't want to get hit.

 

[noahnott]

Looking through the NAR rules for rockets, i didnt catch anything against night flights. Or is this moreover a common sense thing? So can i?

Yep, im still in the hobby and better yet i got my hands on a copy of the Handbook of Model Rocketry. Good book! Btw, my dad finished *his* sailplane which *I* flew into a tree earlier today. Course we got it back =)

Thanks, Noah

 

[ben]

You CAN fly at night but it does state that (I don't have it know so I can't give you a page) the rocket has to use lights or some other material to be seen through the whole trajectory. If you were on your own, I say get a 2" piece of BT-50 clear tubing to go with a BT-50 rocket and wire 5 LED's in there. make sure the compartmanet is sealed from any ejection gas.

thanx, Ben

 

[f16fan12]

The model rocket safety code doesn't mention anything about night flights, but you can do them. Just be careful. Besides the LED idea, you can try one of these:

https://www.uoguelph.ca/~antoon/gadgets/rocket2.html

I've never done one but it seems easy enough.