New Motor Certified

[Steve Shannon]

This is an excellent opportunity to clarify a detail. It is my impression that a specific reload kit must be tested in a specific set of hardware (which might be made by the manufacturer of the reload kit - a regular or ordinary certification - or might be made by another manufacturer - a cross-certification). Cross-certifications by class or type, for example ALL CTI 38mm 4 grain I motors, regardless of propellant type, certified for use in AT 4-grain 38mm cases, never took place, nor did the manufacturers intend for such usage to happen. Is this correct?
I ask this because I have recently been doing a lot of certifications of Aerotech Super Thunder single-use and reloads. This is an unusually stout and fast-burning propellant, and as a potential flyer, I would want that specific reload to have been developed and tested for certification in the specific hardware that I planned to use to put in my rocket.
Those of you who know me know that I have not flown a commercially manufactured motor (except for some Estes B4's and C6's) since 2014, but knowing what I know, I would never try to fly the new K1800ST in anything other than an approved 75/2560 case. I want to make it clear that this is not an official Tripoli policy or recommendation, it is my personal opinion ONLY.

AW

I think you and I spelled it out in your Policies and Procedures Manual, Alan.

Here's what it says:
6.5. Cross-certifications: All of the requirements for cross-certification of reloads from one manufacturer in the hardware of another manufacturer, including numbers and fees, are, in general, the same as for reloadable motors from individual manufacturers. Parties interested in cross-certifying hardware or reloads should contact TMT in advance, as numbers and fees may vary depending on circumstances and details at the discretion of the TMT Chair.

No 38 mm loads were ever cross certified (between CTI and AT) as far as I know. Neither have 54mm loads been. The only sizes that have been cross certified were 75 and 98 mm and not all of them from either manufacturer were certified in each others' cases. To put it simply, a reload must be submitted together with the case the manufacturer wishes it certified in. So, if AT or CTI wants to certify a reload in the other manufacturer's case, they must provide the necessary number of reloads as spelled out in your P&P Manual together with the correct case and with instructions that apply to that combination. In other words, a motor that is both certified and cross-certified is actually submitted at least twice, once with each case the manufacturer wants it certified for.

 

[cerving]

AT and CTI 38mm/54mm aren't going to be cross-compatible because the closures are completely different. The 75mm and 98mm AT/CTI hardware are very similar to each other, and the grain sizes are the same, so it's easy to cross them.

 

[mrwalsh85]

Is that to say that these single grain (or 2-grain) reloads are not certified for use with the RAS.... yet?

 

[jimzcatz]

As I understand it, the RAS was certified as a separate entity. I would think using it is no problem.

 

[StreuB1]

Is that to say that these single grain (or 2-grain) reloads are not certified for use with the RAS.... yet?

RAS applies to all AT reloads and cases that they fit in.

 

[H_Rocket]

Stainless steel seal disk, is that something new? All of my seal disks are aluminum.

 

[Steve Shannon]

As I understand it, the RAS was certified as a separate entity. I would think using it is no problem.

You’re right, Jim. It isn’t a problem. The RAS is simply a component (or set of components) that is approved as a part of the RMS system. It doesn’t require testing with every single motor. Alan Whitmore or John Lyngdal could explain that process.

 

[Steve Shannon]

Stainless steel seal disk, is that something new? All of my seal disks are aluminum.

Not very new. They’ve been out for a few years anyway.

 

[rharshberger]

Stainless steel seal disk, is that something new? All of my seal disks are aluminum.

It would be a good idea to get one, some loads specifically call them out in the instructions iirc.

 

[Rocketjunkie]

I have a 98 mm one that I needed when ST loads first came out. The 54 mm and smaller use the aluminum seal disk.
2 grain L2500

 

[Loki Research]

No 38 mm loads were ever cross certified as far as I know. Neither have 54mm loads been.

One might read this statement and believe it is referring to all manufactures. It is only true for Aerotech and CTI.

Loki, AMW and Gorilla reloads were all approved cross certified in Loki, AMW, & Gorilla 54mm and 75/76mm motor cases. The motor case itself is the only item which can be swapped out between Loki Research and these two former manufacturers as they are more or less identical to each other in design. Our reloads were never tested in each others motor cases because of this. Aerotech and CTI cases have entierly different thread types, different lengths and different closures, so they required testing in each others hardware to receive cross certified approval.

Side note, the Loki Research 76mm motor cases have a slightly thicker wall and thus a larger OD than what 75mm cases do. This is why the nomenclature is different by 1 mm.

 

[Rocketjunkie]

No 38 mm loads were ever cross certified as far as I know. Neither have 54mm loads been.

The CTI 54 mm and down are an entirely different design than Aerotech. Snap ring cases are a different story but the smaller cases aren't that expensive.

 

[jmasterj]

Loki, AMW and Gorilla reloads were all approved cross certified in Loki, AMW, & Gorilla 54mm and 75/76mm motor cases. The motor case itself is the only item which can be swapped out between Loki Research and these two former manufacturers as they are more or less identical to each other in design. Our reloads were never tested in each others motor cases because of this.

I know what's different about the forward closures, but what is/was different between your Loki nozzles and the AMW/Gorilla ones?

 

[Steve Shannon]

One might read this statement and believe it is referring to all manufactures. It is only true for Aerotech and CTI.

CTI and AT was the context of the thread when I made that post. I agree with your point though and I added some verbiage to my post to make that clear.