Old Motors

[phyzzld]

Hi All,

I am a model rocketeer returning to the hobby after a very long layoff. I've been going through all my rocket "stuff" from way back then and found that I still have several old motors. Mostly C's and D's but also a couple F and G's. The motors are easily over 15 years old. Since I'm not sure if they are safe, I do not want to use them. My question is, what is the best way to dispose of them?

Thanks

 

[blackbrandt]

Send them over to me and I'll do scientific analysis to determine if they are safe or not.

Just kidding. Where were they stored? If they were stored inside, they should be relatively safe. Are the F's and G's composite or black powder?

 

[cavecentral]

I've flown much older ones. If they didn't get dropped or temperature cycled to much, they should be fine.

 

[phyzzld]

The motors have been stored inside so there shouldn't be any temperature cycling issues. The F and G motors are composites. The igniters are just as old. Would they be ok too?
Out of curiosity, is there a shelf life for motors? Are there any signs (besides the obvious,ie broken case) that a motor should not be used.

Thanks,
Jeff

 

[Woody's Workshop]

They are Engines, not motors...
Engines burn fuel to produce work or electricity.
Motors uses electricity (or wind or other source) to produce work.
Welcome back to the rocketry!
I would fly them! Unless they are crumbling or a bulge in the casing, send em up!

 

[TNmike]

https://www.nasa.gov/exploration/systems/sls/multimedia/gallery/srmtest1.html

 

[Titan II]

From websites.

Since the introduction of the Pro38® line of reloadable high power rocket motors in 2000, the ProX® line by Cesaroni Technology Incorporated (CTI) has grown to cover every total impulse class from F to O.

AeroTech Master Motor Matrix
Complete list of available motors and their specifications. Last updated 12/6/2016


BTW....I have used 15+ year old motors without any issues.

 

[cavecentral]

Sometime single use composites will have the grains swell ap and you can't get an igniter in them. That is usually a bad sign. Most of the time they are fine.

Usually the least reliable part of old motors is the delay / ejection. Electronic deployment solves that issue. Otherwise, point is a safe direction in case of a lawn dart.

 

[OverTheTop]

I have some BP motors that are about five years old. Tried to ignite one the other day and got nothing. Had been stored in a reasonable location, but may have absorbed too much moisture or something.

The composite motors can sometimes be a bit hard to light if the surface of the grain has oxidised over time. A sealed packet will mitigate against this somewhat. A gentle scraping to get rid of the oxidised layer and off they go nicely again.

 

[JStarStar]

I've used BP motors up to 45 years old with little problem.

 

[dhbarr]

They are Engines, not motors...
Engines burn fuel to produce work or electricity.
Motors uses electricity (or wind or other source) to produce work.
Welcome back to the rocketry!
I would fly them! Unless they are crumbling or a bulge in the casing, send em up!

Vern says motor in interviews, so I say motor.

 

[Zeus-cat]

Vern says motor in interviews, so I say motor.

Well what does Vern know. D'oh!

 

[dave carver]

The motors have been stored inside so there shouldn't be any temperature cycling issues. The F and G motors are composites. The igniters are just as old. Would they be ok too?
Out of curiosity, is there a shelf life for motors? Are there any signs (besides the obvious,ie broken case) that a motor should not be used.

Thanks,
Jeff

I've burned 40 year old motors from the old blue diamond motor packs from ages ago. I have no problems with burning them. In fact, my favorite motor you haven't been able to buy for years. The B14-7, best upper stage ever. I ran out years ago, I keep looking but old hobby stores are long gone

 

[Micromeister]

Hi All,

I am a model rocketeer returning to the hobby after a very long layoff. I've been going through all my rocket "stuff" from way back then and found that I still have several old motors. Mostly C's and D's but also a couple F and G's. The motors are easily over 15 years old. Since I'm not sure if they are safe, I do not want to use them. My question is, what is the best way to dispose of them?

Thanks

I've been flying 1966 to 1978 Estes & Centuri BP motors for Decades. BP motor have NO shelf Life as long as they haven't been heat cycled by storing them in high heat (over 120deg). But even heat cycled motors can still be used if flown within 70degrees f of the highest temperature the motor was exposed. Assuming the motors were transported in a Trailer during Summer days they can see temps of 130-145degess F.
subtract 70 from 145 these motors should be OK if flown on day with an ambient air temp of 75 degrees or higher. In other words most high heat cycled motors should be OK if flown in normal summer time temperatures. 24mm motors are more subject to heat cycled Cato's then 13mm & 18mm motors so a little more care should be taken with D12 & E motors.

It should also be mentioned that most Old pyrogen tipped igniters will be just as good as the motors. I'm still using hords of 1960's Centri Sure Shot igniters with 0% failures.
About the only thing that changes when flying very Old BP motor is it is advisable to scribe an X across the clay Caps on Green & purple label single stage and upper stage motors. This is because the Clay becomes so Dry and Dense the ejection charge sometimes can't break the cap. I've only had a couple Centuri 13mm B motors have this problem but cutting the X in the cap solved the problem.

I'm not as convinced OLD APCP motors will work without scraping the oxidation off the internal grain of the motor propellant. APCP seems to crust over after a couple years making them extremely hard to ignite. I just don't fly APCP motors period. They have too many unknowns for me. EXTRA long delays being one of the most prominent and well documented defects. Aerotech delay times...power you Can't TRUST.

Long story short: Don't discard your OLD BP motors, Just fly them using that 70degree safety margin. APCP motors your on you own.

 

[RoyAtl]

Even Harry Stine originally called them 'motors' (because that's what they called the big ones at White Sands).
Vern started using the term 'engine', and it stuck. I forget his explanation, but I'm sure the fact that 'rocket engine' sounded cooler didn't hurt.

 

[OverTheTop]

Engine or motor? Both are correct. Pick one, or use interchangeably.

Motor is normally used when we are talking about motive power for something, which we are in this case, rather than just providing power for a stationary process.

The rocket engine (or motor) is actually an internal combustion engine.
https://en.wikipedia.org/wiki/Internal_combustion_engine

 

[rockets]

I've flown 16 year old BP motors, no problem, well pretty much no problem. I flew an OLD C5-3, but the ejection charge was more like a 1 second delay. Otherwise, old motors are fine.

Thanks,

 

[phyzzld]

Thanks everyone for all of the great advice. It sounds like I have more usable motors/engines than I originally thought.

 

[rocket_troy]

Thanks everyone for all of the great advice. It sounds like I have more usable motors/engines than I originally thought.

Just to add: BP should generally last for decades – there are caveats with that, but generally yes it should. APCP – well, a lot depends on how it’s stored and what’s inside it. Generally, a basic composite propellant containing no metals or say, Al as its only metallic inclusion will generally last for decades and won’t be affected by temperature cycling or moisture over time. APCPs with significant inclusions of say Mg (especially the uncoated flavours) need to be sealed well from atmospheric moisture. They can last years, but need to be sealed well. As others have mentioned, there are some visible signs of moisture degradation – the grain starts to puff up and the surface can look mouldy. These surfaces are extremely difficult to ignite.
For reloads, you can sometimes re-cut the ends and core – removing the soiled propellant and exposing the unsoiled propellant which will generally be of a much “fresher” appearance (darker shade, more rubbery, visible oxidiser crystals). I’ve certainly done it plenty of times without issue.
Example of a propellant susceptible to moisture degradation is the Aerotech White Lightening propellant used in the smaller motors eg. G64. It often has a greenish tinge to it.

 

[JStarStar]

Needless to say if the paper casing, ejection cap or ceramic nozzle look degraded or damaged in any way, you may indeed be looking at problems.

But again, I've flown motors 40 years old or more and they worked fine.

 

[BABAR]

Fly 'em. I miiiiiiiigggghhhhhhttt however NOT use them in a rocket I really highly value and would hate to get CATO'ed. Just in case!

 

[ayryq]

Fly 'em. I miiiiiiiigggghhhhhhttt however NOT use them in a rocket I really highly value and would hate to get CATO'ed. Just in case!

Yeah, my only CATO to date was a vintage C motor-engine. (Motgine? Engtor?). Utterly destroyed an Estes Astron Skydart II on its second flight. And I've seen a fair share of E9's CATO, so if you've got any of those I'd dunk them.

 

[Cl(VII)]

Someone flew (successfully) an FSI F100 today at Airfest. They delay even worked perfectly.

 

[dhbarr]

Someone flew (successfully) an FSI F100 today at Airfest. They delay even worked perfectly.

AND IT WAS BEAUTIFUL! RIP Big Pink Bertha fins, you're so (d)aft.

 

[BEC]

One added thought. Since I got back in I've acquired and used a bunch of old Estes motors going back to the early 1970s. One thing I've noticed fairly frequently with these is that the delays tend to run short. I don't know why this should be, and I can't say I've done any real measuring (hmmmm....time for some AltimeterThree flights) but I have experienced what seemed to be short delays fairly frequently on, say, 25-year old or older motors. Just one more thing to take into account when choosing what old motor to fly in what model.

 

[JStarStar]

Totally anecdotally, over the years it's seemed to me Estes delays come in 3 lengths: 0.5, 1.5 and about 8.