Safe storage of old engines

[J-Wizz]

Hell all
I recently picked up this ancient Hobby Labs SR-71 rocket glider kit complete with a couple of original E15-PW engines.
I'm guessing these are about 25 years old and I'd like your opinion about how stable they would be after so long.
Do they or the igniters become unstable after this long?
Should I be taking extra precautions storing them?


I really don't want to burn my house down before i figure out what i want to do with it

 

[David Schwantz]

3 or 4 years is the shelf life of model rocket engines. I just happen the have an old gun safe vault that I store all of mine in. I suggest that you ship them to me for safe storage Dave.

 

[David Schwantz]

Just kiddin, they are fine to store. I have had 20 year old ones before. Keep them dry and in a cool place. I would probably use new igniters though, just so there is no hassle at the pad replacing bad ones.

 

[GlueckAuf]

Hell all
I recently picked up this ancient Hobby Labs SR-71 rocket glider kit complete with a couple of original E15-PW engines.
I'm guessing these are about 25 years old and I'd like your opinion about how stable they would be after so long.
Do they or the igniters become unstable after this long?
Should I be taking extra precautions storing them?


I really don't want to burn my house down before i figure out what i want to do with it

These appear to be Ammonium Perchlorate Composite Propellant (APCP) motors. APCP will oxidize over long periods of time, but in my experience, the primary consequence--creating a layer of poorly-flammable oxidation on the propellant--just makes ignition more difficult. Using a slender scraper of some sort that fits through the nozzle to scrape away and expose some unoxidized propellant will improve the motor's ignition in this regard.

It's black powder motors that become prone to cracking over time, especially if they've been exposed to wide temperature fluctuations, that are the greater risk of a cato. As I understand it, the cracks allow far more surface area to burn, over-pressurizing the motor and blowing out the nozzle or delay grain/ejection charge. I don't think that's a concern for your apparently APCP motors.

If you suspect possible rough handling over the decades, check the plastic motor casings for any splits, cracks, deformity, or other damage that might cause a loss of containment when the motor ignites. If there's supposed to be a delay-ignited ejection charge, make sure the BP plug is still present and that the BP hasn't fallen out or become contaminated.

Good skies,
GlueckAuf

 

[J Blatz]

They are safe but may not be usable. White Lightning propellant has a tendency to age poorly in humid climates, with hard ignition and grain swelling. In c-slot configurations like the E15 this can close up the whole slot, preventing the user from being able to insert the igniter properly. I have seen this many times.

 

[boomtube-mk2]

Reading between the lines it almost reads like J-Wizz is worried that the motors might become "Unstable" in the same manner that dynamite becomes unstable, in that the motor/s might either spontaneously ignite or possibly "Go Boom!" if dropped.

And the answer to the above is no, that can't happen.

 

[Back_at_it]

Any place cool and dry is acceptable. As for Shelf Life. I've flown black powder motors that are over 30 yrs old and never had a failure other than a couple that refused to fire.

 

[Cape Byron]

Old Estes igniters don't store well, even in their original packaging. The pyrogen tends to fall off.

 

[David Schwantz]

Hate to tell you this, falls off when they are brand new too.

 

[mrwalsh85]

I wondered if anyone spotted that find - especially with NARAM right there! Did you get all four?

I asked a few folks, no one recognized who might live there.