Aerotech H180W 29mm reload

The question has come up about the ability to use the Aerotech H180W reload, in a non-waivered FAA Class 1 launch due to a discrepancy, in the listings of Thrustcurve .org vs NAR's "NAR S&T's Combined Motor List" of 4/4/15 regarding propellant mass.
Nar show a propellant mass of 125 grams and Thrustcurve.org shows 124 grams.
A vendor sold this motor, using Thrustcurve.org number to a flyer for a FAA non- waivered Class 1 launch.
Any insights or confirmation.

The Part 101 requirement is "(1) Uses no more than 125 grams (4.4 ounces) of propellant;" so either way, it is fine. If it were 125.1 grams then you would have a problem.

Aerotech lists it at 123 grams. The only aerotech 29 mm reloads that cannot be used are the H97J (141 grams), I200W (175 grams) and H268R (166 grams).

The not exceeding 125 grams of propellant H motors are class 1 motors under FAA regulations which does not require a waiver, however they are still considered L1 high power motors under NAR/TRA/CAR regulations and the field requirements are not waived: 100' pad separation distance; 1500' inhabited building separation distance; 1500' minimum field dimension distance.

Bob

I guess I word this poorly!
I am aware of the definition for Class 1 rockets, that is why the request for clarification or confirmation.
The question is DO we ONLY go by the NAR/TRA/CAR combined list for insurance purposes, at NAR/Tripoli sanctioned launch!
I am telling the individual, that we need to abide by, the current "NAR/TRA/CAR combined list"
Terry, Aerotech does list the H180W as 123g propellant weight, in their online, sadly very outdated 5 year old catalog (2009-2010)
However, they also show in their resource section, another very outdated TRA test(1998) that shows 126.7 grams as the propellant weight.
The discrepancies are why I have been told and it makes the sense that the NAR/TRA/CAr current combined list is the proper and only official list.
Am I incorrect in this belief?

kweaver said:

I guess I word this poorly!
I am aware of the definition for Class 1 rockets, that is why the request for clarification or confirmation.
The question is DO we ONLY go by the NAR/TRA/CAR combined list for insurance purposes, at NAR/Tripoli sanctioned launch!
I am telling the individual, that we need to abide by, the current "NAR/TRA/CAR combined list"
Terry, Aerotech does list the H180W as 123g propellant weight, in their online, sadly very outdated 5 year old catalog (2009-2010)
However, they also show in their resource section, another very outdated TRA test(1998) that shows 126.7 grams as the propellant weight.
The discrepancies are why I have been told and it makes the sense that the NAR/TRA/CAr current combined list is the proper and only official list.
Am I incorrect in this belief?

Click to expand...

Going by that current list is all good. It has just been updated.

You have to go by the manufacturer's number. They made the motor and know how much propellant they used and are responsible to report the propellant mass which does not include the ejection charge or delay column by definition.

I'll bet the TRA value is a typo. NAR S&T uses the manufacturer's number as we have no way to measure the propellant in the motor. Neither does TRA. Or CAR.

Bob

kweaver said:

I guess I word this poorly!
I am aware of the definition for Class 1 rockets, that is why the request for clarification or confirmation.
The question is DO we ONLY go by the NAR/TRA/CAR combined list for insurance purposes, at NAR/Tripoli sanctioned launch!
I am telling the individual, that we need to abide by, the current "NAR/TRA/CAR combined list"
Terry, Aerotech does list the H180W as 123g propellant weight, in their online, sadly very outdated 5 year old catalog (2009-2010)
However, they also show in their resource section, another very outdated TRA test(1998) that shows 126.7 grams as the propellant weight.
The discrepancies are why I have been told and it makes the sense that the NAR/TRA/CAr current combined list is the proper and only official list.
Am I incorrect in this belief?

Click to expand...

The 2004 TRA cert document lists a propellant mass of 124.7g while the Aerotech instructions state that it is 117.2g.

Since this is a reload you could weigh the propellant grains but how do you compensate for the mass of the casting tubes?

You, we, who, what????????????????????????? I go by the LIST. How the hell we supposed to know otherwise????????? No simple answer for the OP. Too Bad!! Can we use the LIST or not????????????????????????

UhClem said:

The 2004 TRA cert document lists a propellant mass of 124.7g while the Aerotech instructions state that it is 117.2g.

Since this is a reload you could weigh the propellant grains but how do you compensate for the mass of the casting tubes?

Click to expand...

Just as a SWAG, the reported TRA propellant mass of 124.7 g is the mass of 4 propellant grains in casting tubes and the AT propellant mass of 117.2 grams is the actual propellant weight. The difference between the 2 mass values is (124.7 g - 117.2 g)/4=1.875 g is the mass of the casting tube on each propellant grain. This is a reasonable value for the 29 mm AT casting tubes used for these reload grains: either https://www.rocketmotorparts.com/29mm_Casting_Tube,_0933__OD/p1577809_7781854.aspx or more likely https://www.rocketmotorparts.com/29mm_Casting_Tube,_0933__OD/p1577809_7781864.aspx

As I said previously, the manufacturer bears all responsibility for their motors, including reporting the propellant mass, so you have to go by the propellant mass they list on the instruction sheet provided with the motor. The role of the certifying authorities is to verify the total impulse and average thrust ratings of the motors supplied to them by the manufacturer and to verify that the instructions supplied by the manufacturer with the motor are compliant with NFPA 1125 and are sufficient to assemble and use the motors safely. That's it.

My conclusion is that TRA TMT incorrectly reported the 124.7 g weight of the 4 propellant grains received from AT in a reload kit as the propellant mass which is not correct, so the 117.2 propellant mass listed in the AT instruction is the real propellant mass. In this case it's irrelevant as both values do not exceed the 125 g Class 1 limit.

IMO if you have an official written document that lists the propellant weight of your motor as 125 g or less which is a FAA Class 1 requirement, that legally satisfies the FAA requirement.

Bob