Any one have a chart for amp ratings on igniters?

[ibuildstuff4u]

Hello, I'm looking to see if any one has a chart or list showing the different amp ratings that each brand of ignitors needs to work. I'm building a control box and want to make sure it will work with any type of ignitor.

Thanks for the help,
Dale P.

 

[Pat_B]

I vaguely recall that John Boren did a report on something like that. I had read it on his website at one time but can't find it now.

 

[samb]

Here is a paper John Brohm did a few years ago that you may find helpful:

https://www.rocketshoppe.com/info/Igniter_Continuity_Tests.pdf

Found with the search argument "model rocket igniter voltage".

 

[BEC]

That's a great paper. Saved!

 

[samb]

That's a great paper. Saved!

It really is an exceptional piece of work. I wonder if the test bed is still available ? The Estes PS II Sonic Igniter (grey pyrogen) and Model Rocket Starters (clear "pyrogen") have been released since that paper was published. Hmmm...

 

[ibuildstuff4u]

Yes, that's what I was looking for! This is a great article. Im building a launch controller and so far it comes in at 14 ma when performing the continuity check so it looks like I will have NO problems with it.

Now if someone could post the rules that state the length of wire needed for a launch controllers verses engine sizes I would be all set. I have tried looking at the various model rocketry rules on the web and so far haven't found anything listing the wire length needed for the launch controller.

Thanks, Dale P.

 

[Pat_B]

It's 15 feet for D motors or smaller, and 30 feet for motors above that, EXCEPT when you get into high power motors which start at 100 feet clearance.

https://www.nar.org/NARmrsc.html
https://www.nar.org/NARhpsc.html

What I always found interesting is that many of the controllers available have 15 feet launch cable lengths which really are too short when you consider the distance of cable that hangs down on the ground when you stand up. I think you need a minimum of about 20 feet of cable, or 25 feet to actually be standing 15 feet away for low power operations.

 

[ibuildstuff4u]

What would be a high powered motor? What size of a motor can you do with 30' of wire?

I thought there was a need for 50' of wire too, or does it jump to 100' after the 30' controller?

I fully agree that 15' is too short for any rocket. 20 to 25' is way better.

Thanks, Dale P.

 

[samb]

What would be a high powered motor? What size of a motor can you do with 30' of wire?

I thought there was a need for 50' of wire too, or does it jump to 100' after the 30' controller?

I fully agree that 15' is too short for any rocket. 20 to 25' is way better.

Thanks, Dale P.

High power has a few thresholds related to total and average impulse of the motor(s), propellent weight, and weight of the flight-ready rocket. You can find the details on the NAR web site or at www.tripoli.org (the other national sport rocketry association). Here is a handy one page summary of these guidelines (short answer, H and above is high power, with a few exceptions). Our club pad goes out 50+ft for E,F,G flights. BTW when you're at the Tripoli or NAR sites look for the closest club and go see a launch. You will see some cool flights and meet the local flyers.

View attachment HPR_metric9c.pdf

 

[bobkrech]

What would be a high powered motor? What size of a motor can you do with 30' of wire?

I thought there was a need for 50' of wire too, or does it jump to 100' after the 30' controller?

I fully agree that 15' is too short for any rocket. 20 to 25' is way better.

Thanks, Dale P.

Low Power, =<D, minimum 15' separation distance
Mid Power, E, F, G, minimum 30' separation distance
L1 High Power, =<H, I, minimum 100' separation distance (Note any rocket motor with an average thrust >80 N is a high power motor by definition)
L2 High Power, J, minimum 100' separation distance
L2 High Power, K, minimum 200' separation distance
L2 High Power, L, minimum 300' separation distance
L3 High Power, M, minimum 500' separation distance
L3 High Power, N, minimum 1000' separation distance
L3 High Power, O, minimum 1500' separation distance

https://www.nar.org/cabinet/MRSafetyCode.pdf
https://www.nar.org/cabinet/HPRSafetyCode.pdf
https://www.tripoli.org/LinkClick.aspx?fileticket=RhLaGq2C+HY=&tabid=326

Bob

 

[ibuildstuff4u]

Thanks! I looked all over for some specs on wire length and didn't find much.

I'm building some custom launch controllers to sell and was trying to figure out what length of wire to offer with them. I think I'm going to ship them with 30' as the standard length and then offer other lengths at an additional charge.

Here is a sneak peak of my new launch controller.

It has a battery door on the back for a 9 volt, and a jack on the side for a 12volt input so you can easily hook it up to a car battery.

I have speaker spring terminals on the front to hook up the wire to run to the launch pad, and will offer banana jacks as an option. Personally I think the speaker spring terminals are the best because if a banana plug happens to come off at the launch site you have no way to fix it. With the speaker terminal you can simply re strip the wire and insert if you have any issues. The speaker terminals are also cheaper to buy so the controller can be priced lower with them.

Please let me know what you think of my design.
Thanks, Dale P.

 

[cwbullet]

I like it. That is a very crispy design.

 

[fatdaddynerd]

https://www.gwiz-partners.com/igniters.pdf

that should have everything you ever need to know