can somebody explain to me why hybrid rocket motors are regulated by the
nfpa? I mean Nitrous oxide and plastic/paper/whatever are NOT explosive as
far as I know. Nor it it considered a flammable solid as it doesn't become
such until it ignites. I don't think NO2. Sure a hybrid rocket could
explode I suppose under the right circumstances, but so can this can of
gasoline that I have in the back of my truck. Isn't this another case of
over-regulation? Is there any danger of hybrid rocket motors being outlawed
because NO2 is a greenhouse gas?
please explsin this to me
The NFPA (National Fire Prevention Association) is a non-profit
organization. They do not regulate anything, but they do develope
codes that are used by agencies that do regulate. This includes
several codes that cover the manufacture and//or use of rocket motors.
Being concerned with fire prevention, there is no requerment that
something is explosive. NO2 is an oxidiser, the fuel is flamable, and
rocket motors will start fires.
There are several problems with nitrous oxide from the regulatory point of
view, although I think the NFPA involvement is far more for flight
operations than the motor systems themselves. Nitrous is not an explosive,
but does have some rather unforgiving properties that encourage controlled
access. It is a strong oxidizer, an anesthetic, an asphyxiant, sought after
by certain druggies, and can be used to help create certain categories of
explosives. Therefore I am required (I don't know if this is just the
distributor I use or everywhere) to keep the nitrous in locked storage and
keep an inventory and discharge record. The distributor claims this is a
Homeland Security requirement, and N2O is just one of 40 gases on their
list. Most of the others are truly nasty stuff. This may be because I am
getting medical/industrial grade nitrous, without the odorant. Don't really
With that being said, however, access to nitrous is pretty easy. Local speed
shops are happy to fill your tank (at around $5/pound). To obtain nitrous
from the local industrial supplier I simply had to go down and establish my
bona fides -- I provided copies of my driver's license, NAR card, and a
nifty package of information I printed off the Internet concerning the use
of nitrous in rocket motors. Given that, the distributor was more than happy
to sell me the stuff-- at $2.10 a pound.
As far as hybrid rockets exploding, N2O is a monopropellant under the right
circumstances, and if a hybrid motor goes "monoprop" you can kiss it
goodbye... there will be confetti. The conditions which produce this
condition are complex, but the design of monotube hybrid motors can allow
this to happen if conditions are just right (or wrong, as may be). A major
player in the effect is the gas pressure at time of launch.
BTW, nitrous oxide is N2O, and is indeed listed as a greenhouse gas. NO2 is
nitrogen dioxide, some truly nasty, toxic stuff, and a major contributor to
air contamination.. As to whether N2O can be outlawed as a greenhouse gas, I
have yet to hear that rumbling, although the day may come.
The NFPA creates model codes for pyrotechnics, not just explosives,
that states can incorporate into their laws.
The better question is why does the NAR require HPR user certification
for the use of small hybrid motors that do not require a LEUP? Isn't
this a case of over regulation?
No HPR certification is required for non-HPR motors. Same with TRA.
The two organizations agreed around the time 'G' motors became available.
FWIW, I think the available G hybrids are over the propellant limit for
a model rocket motor and so really are HPR motors.
Flyer certification has absolutely nothing to do with LEUP's or any
alleged "explosive" properties of propellents. Certification is
intended to show that the flyer has at least a minimal level of
knowledge and skill for the use of high power motors.
ray.. Just keep the noise down until the NAR BOT or the TRA BOD gives
guidance on a public response. If you don't grasp the concept, RMR
(Usenet) is a public response....
Any and all RMR posts can be used by either side... Folks that don't
understand this aren't helping the things.
That is not entirely true. The point of user certification is to get
users registered and listed so that authorities can round up the usual
suspects when the need arises.
Bull. You can get the required user certification to fly hybrids
without showing any knowledge of hybrids, of flying of a hybrid motor.
I'm not suggesting that hybrid motors should be sold to minors.
Hybrid motors are a pain in the ass (or back) and are lower performing
than APCP motors. However, they can be shipped, stored and used by
rocketeers who cannot get LEUP storage. Those that can get LEUP
storage are still forced to pay a high price for that privilege.
NAR HPR user cerebration expires within a year of NAR membership
expiration, so continued use of small hybrid motors imposes the
unreasonably high tax of NAR membership. (Please do not get side
tracked on membership dues.)
I'm not sure where I would set the bars for "small" hybrid motors.
Certainly Hybrid motors of less that 62.5 grams of propellant should
be open to purchase and use by adults without any licensing and
certification barriers. Since there are no large "explosive" or
hazardous propellant grains involved, no hazmat shipping, LEUP storage
etc. involved, I would suggest that hybrid motors of up to 4 Oz. of
propellant mass should be available to adults without the additional
burden of certification and licensing fees. (The FAA LMR limit.)
Now certainly there are still issues with igniters and ejection
charges and the matter of what small hybrid motors the market may
provide. I'd still like hybrid motors to be certified, for safety and
performance assurance. While some advocates may say the future of HPR
is not solid, I would say the future of hybrid motors depends on the
outcome of ongoing litigation and future regulation and certification
This apparently changed during the BoT meeting at NARAM. But all I have
to go on is the recording of the NAR meeting posted by Chris Taylor. I
sent an e-mail stating that I thought that their reasoning was flawed
but I haven't heard anything in return.
The reason, as near as I can tell, is because NFPA 1125 has a specific
section for high power hybrids but not one for model hybrids. There is
nothing in any of the NFPA codes that says all hybrids are high power.
Woody, my post had nothing whatsoever to do with our current ATF
situation. It was about flyer certs, not LEUPs. The clear, historical
fact of the matter is that flyer certification was instituted long
before the ATF attempted to assert control over our hobby, and flyer
certs never had anything to do with LEUPs or ATF regs. Flyer certs
(originally called "consumer confirmation") were intended solely to
placate the NFPA. What part of that concept do you have trouble
Whatever. The point is, flyer certs are an NFPA thing, not an ATF
thing, and they have nothing at all to do with LEUPs or the ATF.
Ok, so you don't like flyer certification for high power motors. Take
it up with the NFPA.
Um, what's your point? What do LEUPs have to do with hybrids?
You're the only one who brought it up.
There's no requirement for high power certification to use low-power
hybrid motors. High power certification is for users of high power
Can you summarize the perceived problems, please? Maybe these are
issues that can be solved for you...
The one that isn't going away is carting the GSE around. Until Aerotech
or Alpha get their non-vented lines of motors running. Anyway, I've got
all the stuff in a rolling cooler and that is pretty convenient.
Bob Kaplow wrote:
It takes me less time to prep a Hypertek motor than it does an AMW or
Aerotech reload. I know, I've timed it. Very similar in effort to a
PRO38. On the launch pad the setup is similar in complexity to hooking
up a standard igniter. The launch procedure is more complex because you
have to watch for a complete fill (the most common cause of problems in
my experience) and then switch the controller from fill to fire. Yeah,
I know... it requires skill. What a pain.
On the flip side, I can purchase and store my Hypertek M grain
completely permit free. Most PRO38's, on the other hand, require a LEUP
and Storage magazine. Which one is a royal pain?
Yeah. WHEN it all works. WHEN the stem isn't screwed up, WHEN the GSE
isn't leaking, etc. etc.. Requires skill...ha ha, Mr. smartass.
Requires luck is more like it. You hybrid fanatics are so defensive it
ain't even funny.
I have a permit, and I spent less time getting that than I've seen spent
in the attempt to launch one hybrid rocket.