Old 98/5120 98mm casing and closures

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t-rocket

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Need old timers help-

I have an old AT 98/5120 casing that I used to fly in bigger rockets back in the mid-'90s. The closures are just as old. I was out of rocketry for 15 years and I haven't purchased a big AT motor since 1997, and wondering what's changed with these reloads?

I can see now the current L952W reload is only sold as a plugged motor—although the forward closure on my old casing has an ejection well. The design of the new 98mm forward closure is different-looking than the old one and there is a seal disk now when there wasn't one used 20 years ago.

My question: Can I use the old forward closure with the new reloads? I assume I would have to seal off the end since there isn't a delay grain any longer. Would the parts still fit correctly?

Or will I have to buy a new forward closure?
 
You can use the old closure but you must seal the touch hole. There are no O-rings to seal the delay grain, it just drops into a plugged closure. I still have some ejection well closures. I tapped the touch hole and used a short screw to seal the hole. You will need to buy a seal disk. The new L2500ST requires a stainless steel seal disk (can be used with the other loads but it's heavy).
 
You can use the old closure but you must seal the touch hole. There are no O-rings to seal the delay grain, it just drops into a plugged closure. I still have some ejection well closures. I tapped the touch hole and used a short screw to seal the hole. You will need to buy a seal disk. The new L2500ST requires a stainless steel seal disk (can be used with the other loads but it's heavy).

Very similar to Tom's remarks. I have an old forward closure as well. I drilled out the ejection charge hole to accept a forged eyebolt, installed the eye, backed with a washer and nut, covered it in JB weld. Now I have a sealed forward closure with hard point for recovery connection if desired. I do have to shorten the smoke grains slightly to accommodate the nut & JB weld, but no biggie!
 
Thanks for the replies. I plan to use the L952W reload as it was always one of my favorite motors. I bought the standard seal disk. So, the delay element is gone from the kit, correct? It was replaced with a smoke element, right? Another person said I just needed to assemble using the seal disk, fill the ejection well hole with grease and tape it off real good. Sound right?

T Dungan
OKC
Tripoli #3286 (love that Tripoli gives you your old number back!)
 
The delay element and smoke grain are the same thing. You must seal the touch hole against pressure. The old reloads had O-rings thet went into the bottom of the dekay well to seal against pressure - they are not included in the kit any more. Another option is to rough up the inside of the ejection well (on the outside of the motor - NOT where the smoke grain goes) and fill with epoxy.
 
Post retracted. [Unable to delete due to new site policy.]
 
I've done that with 54s without issue; I doubt a 98 would be any different. I pack a little dog barf on top of the grease too for good measure.
The 54s still have the delay well sealing o-rings and you can just leave out the BP ejection. The 98s don't have these O-rings and therefore there is nothing to prevent the pressure from going around the smoke charge to the touch hole. (When the 98s had motor ejection, there was a washer and 2 concentric O-rings placed in the delay well before the delay (smoke) grain was installed.) After the motors were sold as plugged, these O-rings were included for a few years but were eventually discontinued. You MUST seal the forward closure well enough to withstand motor pressure.
 
The 54s still have the delay well sealing o-rings and you can just leave out the BP ejection. The 98s don't have these O-rings and therefore there is nothing to prevent the pressure from going around the smoke charge to the touch hole. (When the 98s had motor ejection, there was a washer and 2 concentric O-rings placed in the delay well before the delay (smoke) grain was installed.) After the motors were sold as plugged, these O-rings were included for a few years but were eventually discontinued. You MUST seal the forward closure well enough to withstand motor pressure.

Valid point. I have retracted my misinformation.
 
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