AT SU motors.....older....are they safe?

[Horaryelrod100]

Came into a recent Original Initiator starter set, and it came with 3 SU motors. Now I know of the crucial nature of black powder motors being stored correctly, and the volitile nature, but I'm curious as to the aging process of these composite units. By the pics it's obvious the blister has yellowed and if the dates are correct.....1994-1989, as actual maunfacture date, not patent date, then are these safe to use? I don;t know the history of how they were stored or otherwise.

.....

.....Do I even bother attempting to use these, or play it safe and time capsule these things and purchase new ones? Thanks for your input.

 

[J Blatz]

Speaking from much expereince, yes, they are safe.

The only issue you might experience is a shortening of the delay time on the Blue Thunder motor. This could easily be guarded against by using electronics, or you could just go for it.

Fly 'em.

 

[oddmanrockets]

ive have good luck with older motors as long as they have been kept dry and arent swollen and you cant get the ignitor in also i change out the black powder

 

[cavecentral]

Delays being off a little is the only thing I experienced.

 

[jadebox]

Older Aerotech SU motors used a piece of gummed paper (like tape) to hold in the ejection charge. It's common for the charge to have escaped from them. I've built a couple of saucers to use the motors without ejection charges. You could, however, replace the black powder and reseal the top of the motor.

Also, sometimes the propellant swells up as mentioned. It's difficult to get the igniter (even a small Copperhead) into some new Aerotech SU motors. It's really hard to get them into some old ones.

The older motors are often harder to ignite. Sometimes, the delay will ignite without the motor lighting, so you get to watch your rocket sit, smoking, on the pad until the ejection charge fires.

And, there are a few older Aerotech motors that are prone to failure. I got a couple of G38 motors a while back from the same batch and both failed.

Other than the very slight risk of a motor failing, however, as long as you make sure the ejection charge is intact, there's no safety issues using the older motors.

-- Roger

 

[fyrwrxz]

Send them to me for flight testing-I'll certify them and send them back...

 

[Daddyisabar]

I just used some that judging from the price tag were older than yours. Just carefully collect all the loose powder, pour it back in, tape it up, clean the residue off the copperhead and let er rip! Like any AT motor account for a possible bonus delay.

 

[Initiator001]

The E15, F25 and F50 motor are on blister cards where the blister was heat sealed to the card. As long as the blister does not have any openings in it for air to enter, there is no concern about propellant swelling or other environmental issues (Unless the adhesive on the tape disk over the ejection charge has let go).

Hmm, I wonder if I was the one who packaged these motors...

 

[fyrwrxz]

Hi Bob- thanks for not using staples!

 

[Daddyisabar]

The old ones I used were still very tightly packaged, had to work hard to get it open, and once you did you could "smell the 80's.":wink:

 

[dpower]

I've used AT SU motors this old, the only issue being very hard to light White Lightning. Blue Thunder loads this old have lit fine for me.

 

[blackjack2564]

Old motors are what saucers are for.

If they go boom....no great loss or minimum damage.
If delay is off..... no worries.

So windy days + old motors+ saucers = good clean fun!

 

[Syclone]

Speaking from much expereince, yes, they are safe.

The only issue you might experience is a shortening of the delay time on the Blue Thunder motor.
Fly 'em.

Actually, that F50 looks to be from the pre-Blue Thunder days, so it should just be the "classic" AT propellant.

 

[JPVegh]

I burned an old F25 a while back, it chuffed a bit and there was some bonus on the delay. It was still cool.

 

[dave carver]

Are those Econojet motors the one's known as E-CATO-Jets? I know there were two versions. The one's that didn't explode and the ones that did

 

[Donaldsrockets]

Are those Econojet motors the one's known as E-CATO-Jets? I know there were two versions. The one's that didn't explode and the ones that did

The F20W's were generally fine for the most part.

It was mostly the G35W that had problems. I had 3 of those things CATO back to back.

 

[jadebox]

Old motors are what saucers are for.

If they go boom....no great loss or minimum damage.
If delay is off..... no worries.

If the ejection charge is msissing ... all the better!

A couple of years ago, I made a paper saucer with a 24mm motor mount that I flew to use up some old E-15 motors that had lost their ejection charges. It was inexpensive and a lot of fun.

-- Roger

 

[Initiator001]

Are those Econojet motors the one's known as E-CATO-Jets? I know there were two versions. The one's that didn't explode and the ones that did

If the Econojet F20s have a date code of '902417' then DON'T fly them!

 

[5x7]

If the Econojet F20s have a date code of '902417' then DON'T fly them!

Is that the day you left?

 

[neond7]

I recently went through my stash of old AT motors from around 1996. The two loose motors wouldn't light at all, I gave up after three ignitors. Ended up soaking them in water and throwing them away.

The two sealed econojet packs worked, after difficult ignitor installs all four engines huffed and chuffed for several seconds before doing their thing - excellent flights and spot on ejection charge.

 

[Peter Olivola]

Unlike black powder, soaking composite motors in water does nothing to deactivate them. Synthetic rubber won't be phased by the water. What was probably preventing ignition was surface oxidation. That's difficult to overcome in a core burning motor that's ignited from the top of the grain.

IIRC, the correct way to dispose of composite motors is to disassemble them (yes, even single use,) and set up a controlled burn of the grain.

I recently went through my stash of old AT motors from around 1996. The two loose motors wouldn't light at all, I gave up after three ignitors. Ended up soaking them in water and throwing them away.

The two sealed econojet packs worked, after difficult ignitor installs all four engines huffed and chuffed for several seconds before doing their thing - excellent flights and spot on ejection charge.

 

[gdjsky01]

I burned some old E,s and they were fine. The hardest part was figuring out how to seal the top without getting tape between the casing and the MMT. Just to make sure the disk did not come loose.