At motors

[kelltym88]

Hello everyone!!!! I came across an auction for a bunch of AT motors, but they are 20 yrs. old. They have been stored in a cool, dry place and in their original blister packs, but I wanted advice from the experts. Should I even think of bidding and take a chance or pass. What do you guys out there think? Thanx.

 

[Johnnie]

Being that old, they would be collectors items only...why? because they would not be certified anymore. You could not fly them at any commercial or EX launch.

 

[powderburner]

Even if he just wants to go launch by himself, will AT motors that old still work? I thought they oxidized slowly (no matter how they are stored) and lose a bunch of punch. And I have to wonder how easy it would be to ignite them (as difficult as it is already to get the NEW ones lit).

You guys who fly gobs of composites: how old is too old?

 

[Micromeister]

That's what I've heard also Powder! after a few years APCP breaks down badly, unlike BP motors which have been proven to be just fine after much longer, I still fly Old BP motors from the late 60's and 70's. The only caviot to flying old motors is you have to scribe and X in the clay cap which has dryed hard as a rock to allow the ejection charges to work porperly, and not fly them at sanctioned events. Decertifing motors makes about as much sense as saying though out all your audio tapes after 10years. Matte Steel did a comparison study a few years back on the relative power lose of BP and AP motors over time.. I'll tey to lay my hands on it agian, If I can I'll scan it and post it here.
but like I said I still fly B14's and 1/2A6-0s motors on a semi regular basis Centuri 13mm B4-4's anyone

 

[daveyfire]

They don't lose any oomph, they just get a little harder to light. Composite propellant is good for a loooooooong time. APCP probably does decompose over time, but when encased in a lot of rubber binder and stuff, it is really inhibited. I think 20-30 yrs old, you should be all right. Just check the grains to make sure the right amount of curative was used (so they don't become rock hard), scuff up the top of the core for easier ignition, and let 'em rip!

Another thought I just had -- older AT motors had very little in the way of metals or burn rate catalysts (no need for em -- worked just as well and made the propellant cheaper), so they should just be basic straight up AP/Binder. That would further stabilize the mixture because there would be no odd agents to decompose or oxidize in the propellant.

Hope this helps!

 

[kelltym88]

All this advice....well let me add to it. Here are the motors in question, any thoughts...

2, G42-8W-5A2C1. 2, F44-5W-5A33D. 2, F25-6W "white lighting" 5B138. 2, F14-4J "black jack" 5B138. 2, F50-6W 5A2C8. 1, F25-6W-7C6G. Also includes 4, D21 motors with 4,7, and 10









" Here's to swimmin' with bo-legged women"

 

[Rocketjunkie]

Originally posted by kelltym88
All this advice....well let me add to it. Here are the motors in question, any thoughts...

2, G42-8W-5A2C1. 2, F44-5W-5A33D. 2, F25-6W "white lighting" 5B138. 2, F14-4J "black jack" 5B138. 2, F50-6W 5A2C8. 1, F25-6W-7C6G. Also includes 4, D21 motors with 4,7, and 10

These motors are 10-12 years old. The blister packs were introduced in 1991. They will work just fine, I've burned older motors and apart from being more difficult to ignite, they worked fine. The supplied Copperheads will not work anymore, use a good hot dipped igniter such as Magnalite.

 

[marvSRG]

I've flown a vintage AT 18mm F55T and an F44W. Both worked fine but were a bit hard to light (mainly the F)44. After sputtering a lot and popping the rocket up and down, the F44W was awesome in my Estes Black Brant!!!! Check the pics out under the most recently posted photos (I think it's June or July 2003...yeah, that's recent) on my site which is linked below.

 

[kelltym88]

Thank you all, I think I will see if I can get them, I appreciate all your input. Oh, where can I get some Magnalite igniters.Thanx.








Is that a rocket in your pocket or are you just glad to see me.....both!!

 

[astronboy]

This summer, I launched an Aerotech E30 that I had bought in 1991. It had been rolling around in my range-box all that time. Although I cannot really say what will happen with any other motors, This one worked fine.