on the right side of the law

[Stewart32]

Can an non certified individual use a 29mm Dr Rocket RMS or are all possible case/load combinations in "certification" teritory?

Thanks

 

[Chilly]

There is no mid-power Dr. Rocket hardware that I'm aware of. That puts you in "certified" territory all right.

 

[BlueNinja]

Yea, the 29/60 and possibly the 29/100 you can, the 29/60 i believe is as low as an F and the 29/100 can take Gs.

 

[BlueNinja]

here it is

https://www.drrocket.com/sizematters.asp

 

[Missileman]

even the 29/180 will take a G75J reload.
I have 2 just waiting for the right moment

 

[Missileman]

I guess I should have mentioned that the G75 although not a NAR or Tripoli certification required motor it is an LEUP motor.

 

[UhClem]

The G75 is a high power rocket motor requiring that the flyer be a certified user.

There are three ways to be classified as a high power rocket motor:

1) Average thrust greater than 80 Newtons.
2) Impulse greater than 160 Ns.
3) Propellant mass greater than 62.5 grams.

The G75 has 104.3 grams of propellant. Therefore it is an HPR motor.

 

[Missileman]

UhClem
I am trying to find a refrence for that.
Tripoli website just says level 1 certification for H and I motors.
Nar says the same and in the model rocket safety code it says up to 125 grams of propellant.
62 grams is indeed the cutoff point of BATFE regulations but has nothing , as far as I can find, to do with NAR or TRA certification.
Perhaps I missunderstood.

 

[rstaff3]

Tripoli's code is NFPA 1127. HPR is defined as:

A rocket with a single motor over 160 N-s, or 320 total installed impulse, or over 80 N-s average impulse. There is also a weight limit of 53 oz.

As noted above, the 62.5 gm is not a cert issue, it is a BATF issue. Currently, you can still buy reloads whose grains are less than 62.5 gms without a LEUP. This will change when the BATF implements the lastes set of changes that are somewhere in the comment cycle. Some may dispute this point but the vendors sare selling them.

 

[UhClem]

NFPA 1127 2002 edition. A copy of which is sitting right in front of me says:

---------------------
3.3.15.1 High Power Rocket. A rocket vehicle that (1) is powered by one or more high power rocket motors......

3.3.17.1 High Power Rocket Motor. A rocket motor that has more than 160Ns but no more than 40,960Ns of total impulse, or an average thrust greater than 80N, or more than 62.5 g of propellant, and that otherwise meets the other requirements set forth in NFPA 1125.
-----------------------


NFPA 1122 says basically the same thing.


There is also this from the NAR web site:

--------------------------
1. Who Needs High Power Certification?

A person needs high power certification if he:

1. Launches models containing multiple motors with a total installed impulse of 320.01 Newton-seconds or more, or

2. Launches models containing a single motor with a total installed impulse of 160.01 Newton-seconds or more, or

3. Launches rockets that weigh more than 53 ounces (1500 grams), or

4. Launches models powered by rocket motors not classified as model rocket motors per NFPA 1122, e.g.:
1. Average thrust in excess of 80.0 Newtons
2. Contains in excess of 2.2 ounces (62.5 grams) of propellant
3. Hybrid rocket motors

--------------------------

https://nar.org/hpcert/NARhpdetails.html


I do not know how or why the 62.5 gram limit was added to the NFPA codes. But it always surprises people to learn that motors like the G33 and G75 are in fact high power rocket motors requiring user certification.

 

[Missileman]

That does surprise me, Times they have changed appearantly.
I can bet why the 62.5 gm was added but we wont go into that here.
That does limit the non certificate reloads for 29 mm dr. rocket casings. So back to original question, yes there are 29 mm dr. rocket casings that have reloads that don't require certification but the size are limited

 

[rstaff3]

ACK, I apologize for spreading mis-information. It appears my copy is a skosh to old (or I am...or both). Thanks for the correction UhClem.

 

[UhClem]

There are a few model rocket motor reloads available for the smaller 29mm RMS cases. Very few.

F37W and F62T for the 29/60 case

G54W for the 29/100 case

The other reload for the 29/100 case is the G104T and is a high power motor because of its average thrust being greater than 80 Newtons.

I have used a few of these and have a couple G54 reloads on hand. I picked them up to use in the first flights of my PML Mini-BBX/Terrier two stage rocket. Which will emerge from the painting process one of these days.


I had a G104T reload once that taught me to examine the parts more carefully. I tried several times to light the motor and it just kept spitting out the ignitors. Which was a good thing. When I disassembled the motor afterwards I discovered that one of the two propellant grains did not have a center hole! If the motor had lit, it would have had one core burning grain and one end burning grain. Which does bad things to thrust levels and ejection delays.

All turned out OK as Gary Rosenfield and company turned up at a big Texas launch that year to promote a few things. When I showed the reload to Gary, he traded me a spankin' new H220 reload for it. I think the H220 was either not yet certified and this was a demo flight or the ink on the certification was still drying.

 

[Ryan S.]

uhclem, you may be right, however I have bought and flown many G104 and G75 loads. I am not sure how it all works but your research seems correct so i guess you are....and I got lucky

 

[shockwaveriderz]

how did that 62.5 gr limit get into the NFPA codes: well OUR NAR/TRA placed it there for us.... wasn't that nice of them?

 

[DavRedf]

Without trying to start the controvercy again, if you dont go to TRA/NAR meets and can find someone to supply you with motors you can fly what you want when you want. Having said that its best to go the route and get certified (ar'nt we all "certified" ) it makes life easier and opens a lot of doors ,as in meets etc, plus the insurance is worth it on its own.

It is possible to fly without certification, I used to, but it get lonely on your own.

David