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...

[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.

[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!