Help me understand AMW, AMW Pro-X, Gorilla, and Loki

Loki Research said:

One caveat to this is the Gorilla 54/2550. The internal dimensions of the Gorilla case differ from that of AMW or Loki Research. The retaining ring end margin (distance between snap ring groove and the end of the case) is .200" on the Gorilla 54/2550. The end margin for the AMW 2550 and Loki Research 2800 case is .250" The .100" extra space should be taken up with an extra nozzle washer placed at the top of the bulkhead if using the Gorilla 2550 case with AMW 54/2550 reloads or Loki Research 54/2800 reloads.

One other difference in the Loki Research hardware (most all, but not all) is that I have made efforts to make the thrust rings more compatible with retainers like Slimline by reducing the thrust rings outside diameter, making them thinner, and in the 38's, moving it back further to the end of the case. I do not believe Slimline retainers will work with Gorilla or AMW of any size without major grinding down of the thrust ring.

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Hi Scott - yes, I seem to have run into the thrust ring issue. I just picked up a 54mm hardware set from Mike Fisher and the aft ring is too wide to fit in an Aeropack or Slimline retainer. Can one use a smaller/different thrust ring?

Wilson,

The diameter of my 54mm thrust rings will fit both Aerpack and Slimline, but the distance from the front of the thrust ring to the end of the case needs to be about .430". I don't have either retainer in hand to get a maximum distance though, but I know mine are a close fit in the Slimline. I believe there is more room though front to back in the Aeropack. My 54mm thrust rings are also .047" thick so there will be a fair amount of play inside the groove if Mike is using the AMW/Gorilla style/size thrust ring. The thrust ratings of both rings are very high though so I seriously doubt you'd ever see it fail in a groove that is too wide.

I just ran across this since it popped up in my unread threads. I'm curious now, there are some (I thought) CTI reloads that ThrustCurve seems to list as AMW instead. For instance the 543I297. I don't know how to make a direct-link to a page on thrustcurve.org, but if you search for 543I297 the page says the manufacturer is "Animal Motor Works (Cesaroni)". So does this reload work in a CTI Pro38 case, or does it require an AMW (ProX38?) case? I have an order for this reload in shipment right now but only have the CTI Pro38 cases so I'm suddenly concerned that I bought something I won't be able to use, or that worse-yet might appear to work and then CATO because it wasn't meant to be used in a Pro38 (6GXL w/spacers) case.

I noticed this originally because I had searched ThrustCurve for CTI motors, and this one along with a few others I was interested in (okay, I like sparkies) didn't show up, at first I thought they were missing from TC's website but when I later expanded the search I saw that they appeared under AMW instead of CTI. At first I assumed this was perhaps just someone else making motors for CTI cases, but earlier posts in this thread suggest it's something CTI picked-up to continue to make reloads for a different vendor's cases, hence my confusion/concern.

Thanks in advance.

https://www.thrustcurve.org/motorsearch.jsp?id=646
This shows that the case is a Pro38-5G case. No AMW case required.

I-297 is for the CTI Pro-38- 5 grain case.
You are fine.

The only ones made for AMW snap ring cases, are 54mm & 75MM, those are called AMW-ProX

Thanks. It also doesn't help that at the pro38.com site (specifically here) there's a youtube video link next to the 543I297, and that video's description says AMWProX38-3G (I guess the fact that it says "3G" instead of "5G" is a clue that it's just plain wrong), but it also mentions AMWProX instead of Pro38 for the I297.

One motor hardware mystery I have is the potential compatibility of 75mm and 98mm CTI loads in Aerotech casings and vice versa. (Of the same size, of course.) I have heard that they are compatible, but haven't found a definitive explanation.

For the most part the CTI loads will fit in AT cases.

You must check the individual instructions to be sure, there are a few won't, for the most part they will.

Read the pic below right from the CTI website, all you have to do is go there and read up on it. Click on any re-load and read instructions for compatibility. If it comes with RMS/AT o rings..... it will.

All reloads come with both types of O rings, one set for CTI the other for AT.

This came about years ago after the AT fire. Many colleges and government agencies, needed re-loads for their 75 & 98 AT hardware, to continue with their research programs.
CTI was contacted and agreed to make them. At this point the only thing they made was 38's.

So when they decided to do Hardware them selves they made it compatible with AT....... so loads they already had, would fit.
The difference is:

AT hardware uses the O-rings in compression...like a garden hose.
Cti O rings fit in a groove in the nozzle & forward closure

Hence the need for 2 sets with every reload...so they can be used in both types of hardware & yes they are certified as such.

I don't know if At reloads are certified for use in CTI or if they fit. I do know the supplied O rings will NOT work.

I have used a few CTI M's in AT hardware myself.

Loki Research said:

Wilson,

The diameter of my 54mm thrust rings will fit both Aerpack and Slimline, but the distance from the front of the thrust ring to the end of the case needs to be about .430". I don't have either retainer in hand to get a maximum distance though, but I know mine are a close fit in the Slimline. I believe there is more room though front to back in the Aeropack. My 54mm thrust rings are also .047" thick so there will be a fair amount of play inside the groove if Mike is using the AMW/Gorilla style/size thrust ring. The thrust ratings of both rings are very high though so I seriously doubt you'd ever see it fail in a groove that is too wide.

Click to expand...

I believe it's the same as AMW/Gorilla. Anyways, my solution for my 54mm was to not use a Slimline, but I'm thinking I'll have the same problem in 75mm. If the fit is close I may just grind down the thrust ring a little...

The situation is almost the same for Loki 76mm, only they do not fit a Slimline. You have to grind about .025"-.030" off the thrust ring. They fit Aeropacks great though.

Loki Research said:

The situation is almost the same for Loki 76mm, only they do not fit a Slimline. You have to grind about .025"-.030" off the thrust ring. They fit Aeropacks great though.

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Good to know - thanks. Seems workable!

Slim Lines were never intended to fit.
I asked Giant Leap about it once.

JD

Loki Research said:

The situation is almost the same for Loki 76mm, only they do not fit a Slimline. You have to grind about .025"-.030" off the thrust ring. They fit Aeropacks great though.

Click to expand...

JDcluster said:

Slim Lines were never intended to fit.
I asked Giant Leap about it once.

JD

Click to expand...

Interesting to know.

My favorite way to retain snap ring hardware is using a ring that slips over the end of the motor sandwiching the thrust ring between the aft thrust plate and the retaining ring. Secured with threaded inserts in the aft ring and a couple stainless screws going through the retaining ring. Won't work in minimum diameter though. For that I use tape. Friction fit on the case OD, with a wrap of aluminum tape over the rear and folded around the aft end of the motor.

Binder Design said:

My favorite way to retain snap ring hardware is using a ring that slips over the end of the motor sandwiching the thrust ring between the aft thrust plate and the retaining ring. Secured with threaded inserts in the aft ring and a couple stainless screws going through the retaining ring. Won't work in minimum diameter though. For that I use tape. Friction fit on the case OD, with a wrap of aluminum tape over the rear and folded around the aft end of the motor.

Click to expand...

That sounds a bit like the EZ retainer! I'll probably go that route for my next non-MD rocket.