18 mm & 24 mm RMS - How practical?

[hokkyokusei]

I love my 18 & 24mm casings!

 

[bcdlr]

Okay, you guys had me sold but then you started talking about igniters. Is it really hard to get them lit?
N3TJM I read your write up on engines and it was helpful. But I don't really understand what your igniters are. Can you take some pictures?
What is Magnelite pyrogen? I would assume it is something like the stuff on Estes igniters...
What do you other guys use to light your composite motors?

 

[Justin Horne]

Not having any experience with igniting the motors, I can only tell you about the actual igniters, as they are the same ones (just shorter) as many 29MM igniters. They are called copperheads and are one long piece. They are 2 strips of copper separated by an insulator. Put tape tabs (one on each side) then pace your igniter clip on the tape. This way the igniter touches only one side of the igniter, and the other touches the other side, and the tape stops them from short circuiting. The igniter has a crimped area at the top, and pyrogen on it. The way it works (in theory is the current flow up one side, through pyrogen, down other side, and completes the circuit.
The are often called crapperheads because this doesn't always work... I have pretty good success with them. Often the copper touches past the insulator, and it won't work. A good way to get around this is to gently scrape an exacto knife along the edge to clear any flashing. They actually do work pretty well if you used the tape right. They just don't have quite the success rate of others. For some larger g's and up, aerotech supplies real igniters that work great.


The reason magnalite is used is because, from what i gather, the igniter, even though it burns, won't get the motor lit. The extra pryogen would help it get really hot and light the motor...

Ok, typing fingers sore, but i hope this helps...

 

[n3tjm]

Originally posted by bcdlr
N3TJM I read your write up on engines and it was helpful. But I don't really understand what your igniters are. Can you take some pictures?
What is Magnelite pyrogen? I would assume it is something like the stuff on Estes igniters...

Sure thing about a picture.

If you want me too, I can draw up the methdd I used to create the home made igniter, which can fit in the small throat of these motor's nozzles.

I have found that these 18mm motors are hard to ignite, I go through one copperhead igniter after another, especially with the WL loads.

You can get Magnelite Pyrogen at www.rocketflite.com.

Magnelite pyrogen is the best pyrogen out there. I tried many things, and this is my favorite. Reasons why its my favorite

- Stuff lasts forever - some brands, once you mix em, they only have a shelf life of a couple weels.

- Igniters last forever - the igniters do not go bad due to humidity. Most other pyrogens I trired had this problem, especially the conductive kind.

- You can double dip. Most pyrogens do not like that.

- If you forget to add acetone to the bottle, and it drys out... you can add more, and the stuff is still good. This is the only brand that advertises that feature. I am not sure about the others.

- I use Magnelite for all my ignition needs... I dip copperheads and solar igniters in them. Decreases misfires signifficantly (but wires are better then coperheads because copperheads burn to fast). I also used it in various staging, and small nozzle bp ignition techniques.

-

 

[bcdlr]

I found a great thread on making ignitors:
https://www.rocketryforum.com/showthread.php?s=&threadid=8899
They had lots of info. Have you ever tried "Electric Igniter pyrogen" from Firefox?
https://www.firefox-fx.com/ignition.htm
There part number is SECSQUIB
The stuffs a little cheaper than the other but can't be reconsituted. Great picture of a home made igniter going off made with that stuff.
Boy did I ask a BIG question!!

But I may try it. Who knows?

 

[n3tjm]

I tried it... more then once... and each time they only have a shelf life of a couple weeks. Even when dipped in a sealer . I know I am not the only one that had a problem with that stuff....

Matter of fact, I have a bottle of that stuff sitting next to me... all dried up .

 

[Justin Horne]

Re-mix with acetone?

 

[hokkyokusei]

I make my own igniters too. Igniterman kit and 30 AWG wire wrapping wire. They work great in the small nozzles of these motors. Here's a pic with an estes igniter for scale:

 

[n3tjm]

Originally posted by Justin Horne
Re-mix with acetone?

I have not tried it yet... but I heard the bonding agent Firefox uses will not break down in a fashion where it is reusable. I plan to try it again... but I only used the stuff for a quick fix, where I needed low current ingiters right away. They were good for about a week.

 

[Stymye]

Doug,it takes 24 hrs to disolve the firefox binder..pour in the acetone and let it sit.

 

[bcdlr]

Well I have a 18 mm & 24 mm case on the way (thanks to a TRF member).
Should I take the plunge and make some igniters or try and use what comes in the reloads?
Or I guess I could buy some other igniters to get started...
The 24 mm will work great in my Video Icarus (D motor mount). When I get it test flown and see how it flies and transmits video I'll try it on an RMS load.
Thanks for all the help and advice!

 

[DynaSoar]

Originally posted by bcdlr
I searched but couldn't find much information.
I'm a relatively new BAR and RMS is new to me.
Are the 18 mm & 24 mm RMS very practical? How long does it take to reload that kind of thing...
How does it compare price-wise?
How does it compare power-wise?
I've tried reading the documentation but didn't get much from it.
Am I just better off sticking with 'regular' motors unless I need a lot more power for something?
Sorry if this has been answered before or somewhere else...

Powerwise, more so. Price wise, less so, once you've flown enough to make up the cost of the motor.

I got the complete 18/24/29 set. I haven't used the 18 or 24 at all, because (1) I've had a huge stash of 18 and 24mm motors for months, and (2) I like to prep my birds a day or two ahead of time to save time at the launch. People have said RMS loads should be kept in the bag as long as possible.

Frankly, I still prefer S/U motors. I'll eventually fly these, more as a learning experience than anything regular.

 

[n3tjm]

Originally posted by DynaSoar
I like to prep my birds a day or two ahead of time to save time at the launch. People have said RMS loads should be kept in the bag as long as possible.

I do the same thing... you can load the motors ahead of time. I have loaded them the night before, installed into rockets, ready to fly the next day without problems. Its prolong periods of time that may cause a problem... if you don't plan to use the loaded motor right away, leave one of the closures slightly loose.

Originally posted by bcdlr

Should I take the plunge and make some igniters or try and use what comes in the reloads?

Depending how old they are, the regular igniters should be fine with the 24mm reloads. I never had luck using Copperheads with the 18mm D13 motors, I had better luck with D24's.

Making my own igniters usually solves my ignition woas.

 

[SpartaChris]

I think price wise and power wise, an 24mm RMS system is a great deal. Considering you can get 3 F reloads for around $20 as an RMS, yet a pack of E-9's runs almost the same. So you get more power for almost the same money. If Estes were to make an F motor, it would probably be around $25 for a 3 pack.

Not to mention there is something nice about having the ability to launch a D-24 in my Estes Bull Pup. Plus those loads are about the same price as an Estes pack of D-12's, maybe even a buck or two cheaper.

So yes, you save more money the more you fly, but I think the power you get from an RMS system more than makes up for the cost of the casing.

Just my $.02. You can keep the change.

-Chris

 

[Missileman]

Try the ignitors from the reloads first.
From personal experience I have yet to have a failed ignition from a copperhead (knock on wood)

 

[SpartaChris]

i haven't had a failed ignition from a copper head either. they are just a pain in the @$$ to use is all..

-Chris

 

[stevecarr]

With the RMS igniters if you take your time and handle them properly you dont have a problem with them. The only problem I have had is with the aligator clips the club uses get dirty, but a piece of sand paper from my range box fixes that. I don't use the clip for the igniters I have a small block of wood , lay them flat , and shine them up with a knife and use the masking tape method. No problem.

 

[SpartaChris]

I have found that wrapping masking tape around opposite jaws of the alligator clips works a bit better than putting the masking tape on the igniter. it's easier, you just have to make sure you have one side connected and the other side blocked, and vice versa.

-Chris

 

[Missileman]

Originally posted by SpartaChris
I have found that wrapping masking tape around opposite jaws of the alligator clips works a bit better than putting the masking tape on the igniter. it's easier, you just have to make sure you have one side connected and the other side blocked, and vice versa.

-Chris

Exactly the same way I do it.

 

[gerbs4me]

I've never had any luck with copperheads

 

[loopy]

I run about 98% success rate with Copperheads. I usually hit the clips with sandpaper then tape one side of the clip with about two wraps of masking tape. I also tape the igniter in, and use a pen/pencil to poke a hole through it to let it breathe and not overpressurize. Works great!

Loopy

 

[stevecarr]

The one thing I do that is important is take my time. Make sure you have a good ELECTRICAL, not mechanical , connection.
Clean clips and ignitor make all the difference.

 

[iceage]

Originally posted by SpartaChris
i haven't had a failed ignition from a copper head either. they are just a pain in the @$$ to use is all..

-Chris

Easy solution for copperheads:

Carefully take a lighter, you know-the kind smokers use, and GENTLY heat the end you attach the nasty AT adapter to until the two copper layers separate. There is a dielectric insulation between them that can melt, so be a little careful. Standard alligator clips on your 12V system can be used. Works like a charm.

Patrick

 

[bcdlr]

Does anybody remember seeing a site that had an Copperhead igniter clip made from a clothes pin?
It had one conductor on one side and one on the other so that you just clipped it to the Copperhead that way.
Another alternative - I wouldn't think it would be a big deal to make a self-adhesive 'insulator' similar to the Quest igniter pieces out of an address label. I've got some nice little hole punches that I could punch the holes with.
I'm planning on using some nice NiMH batteries I have: 9.6 V, 3100 mAH! They came out of satellite phones... And they're not very large either.

 

[BlueNinja]

well ,the copperheads are recommended for use with a 12v battery... you might be fine with the 9v though. I tried one with a 6v and it took about 5 seconds to light...

 

[Donaldsrockets]

I use my 24mm RMS in my Art Applewhite oddrocs, great motor for them.

I also use a friends AT controller hooked up to a 12 volt gel cell hobby battery which works great.

 

[bcdlr]

I'm in business! My 18mm & 24mm RMS hardware arrived today. I bought them from a friendly TRF member.
Now, what re-loads to I buy first?
Decisions, decisions...
If my Quest Icarus Vid-Roc (D motor modified) goes well on its maiden flight I may try to send it up with an RMS motor...
I have a Big Daddy about 85% complete that might fly with it as well.
Too many to choose from. Gosh ain't life great?

 

[n3tjm]

D9's and D13's are my favorite motors to use in Estes "D" powered rockets. The D9 has an awesome burn. Over 2 seconds .

I also love the E11, E18, and F24 loads. Can't go wrong with those.

 

[loopy]

E18-4 is perfect for Estes Big Daddy, Phoenix, and Executioner! I had to add some nose weight for the BD and the Phoenix, but I also built those with basswood fins and a LOC motor tube instead of stock, and epoxy fillets, but I tend to build tanks instead of rockets...lol That is also a good load for the AT Mustang, incidentally.

I'm hoping to get some D's for my Prowler soon, and some F's for the other rockets! I'm think and F24 in the Executioner would be quite nice indeed, and possibly the F39 in the Phoenix...

Loopy

 

[bcdlr]

Originally posted by n3tjm
D9's and D13's are my favorite motors to use in Estes "D" powered rockets. The D9 has an awesome burn. Over 2 seconds...

Okay guys you got my curiosity going.
A couple of questions that come to mind:
Basically speaking can you use the RMS motors "as-is" in place of BP motors given the rocket can handle it, etc.?
This is a bigger question - maybe I just need to look for "Rocket Motor Specs for Dummies" - How do I decide what motor I want? I mean from my standpoint it seems like the longer burn motors are more ideal. Otherwise you have a quick powerful burn - a no seeum. Motors light, rocket is gone, you see smoke. I would think in most, if not all, cases I would want longer burn motors.
If this is too big a question please point me in a good resource direction.
Keep in mind my applications - 18mm & 24mm RMS motors in "Estes" class rockets...
With one exception - I've got a Semroc SLS Jaguar that will probably fly on 24mm RMS motors...