Making rms cases?

[troj]

At a Tripoli launch, it's a Research motor and allowed.
At a NAR launch, it's an uncertified motor and not allowed.
If you sneak it through a NAR check in and something bad happens, insurance won't cover it.

This is the correct answer.

Editing to add that as a Research motor, AeroTech isn't going to provide a warranty of any sort.

 

[2-0turbo]

Rocketjunkie,
Yes, DOM 6061-T6 seems to be a good choice. And it sounds like you know what you're doing. Did you single-point the threads on a lathe? Do you have a machine shop? Machining experience?
My point was not that someone with expertise and good shop judgement (as I suspect you have) cannot make a casing. But rather, the OP in asking "Is it possible to make an Aerotech case?" seemed to indicate that production decisions (like alloy, which machine tools, etc) were not familiar to him. Pressure inside these engines is cited as "700-3500 psi" which implies failure modes that anyone making one of these should be aware of. So my point was "Yes, you can do it, but to do it properly you really need to learn a lot of skills and be aware of safety implications. And unless you already have a lathe or a friend with one (and in fact, even if you do), making a case will likely be more expensive than buying one".
I grew up working in my Dad's machine shop on and off. I'm an engineer by training but I never forgot just how good a competent Tool and Diemaker, or a journeman machinist really is. In fact, if I had the time and money I'd put my Monarch 10EE into better shape and make casings myself. As it is, I'm going to have to sell the thing.

How much you want to sell that 10EE for?

If you discount what your time is worth, I can make a casing far cheaper than I can buy one. Granted, it isn't going to be anodized. Mass production really helps AT out on this one as they churn these out on CNC machines and get large batches anodized all at once--their all-in cost is far lower than I can achieve with my manual equipment. Other than the finish (anodizing), the end result is the same. BTW, there is no post-process HT required on 6061-T6 if you bought it already tempered and didn't anneal it (which you wouldn't want to do--it would machine like bubble gum). If you did anneal it, you can easily get the T6 temper back in your home oven.

As this is a hobby for me (and many folks), the amount of time I sink into it and what my time is "worth" is irrelevant. It's a hobby and they are for wasting time and money while bringing enjoyment.

 

[StuartL_UK]

There's a lot of really great info here from the US perspective, but the OP is based in the UK where many rules are different While many (most?) of the readers of this thread are based in the US it's worth calling out that generalizations for NAR and Tripoli aren't internationally standardized and the defacto HPR authority* is UKRA. UKRA operates under slightly different rules due to the different legal and geographical landscape here.

Whether using an unapproved manufacturer casing invalidates the classification and approval of a motor reload is untested in law here. It's definitively illegal to manufacture or modify any quantity of propellant, explosive substances or explosive articles. Prosecutions have occurred and I wouldn't want to be the first person to defend a home-made casing in court.

In my opinion, and echoing the earlier post, it's just not worth it for either Cesaroni or Aerotech motors. Buy them new, buy them secondhand, rent them or borrow them from other flyers. There's no question of legality, you have warranty on your side and you can focus on the rocketry rather than whether your casing thread is as accurate as you thought it was and whether you got the length exactly right to compress the O-rings perfectly.

*Important: UKRA is not an authority in any legal sense, it is the consultative body for high power rocketry for both the BMFA and CAA. I refer to it here as the defacto authority because all current high power rocketry clubs in the UK operate with UKRA as their non-governing advisory body. UKRA safety code, processes, etc, are not a legal requirement for individuals or organizations to participate in any level of rocketry.

 

[tsmith1315]

In my opinion, and echoing the earlier post, it's just not worth it for either Cesaroni or Aerotech motors. Buy them new, buy them secondhand, rent them or borrow them from other flyers

Are DMS single use motors available over there?

 

[StuartL_UK]

Are DMS single use motors available over there?

Yes