Glen
Clearly you're thinking of old hybrids. Yes they hissed and didn't have
a smoke trail, but that stuff is ancient history. There is much better
stuff available now. You should try the stuff from Contrail. They sound
like (some reloads sound even better) than the equivalent solid at the
same impulse rating. And depending on the vendor you can even get
sparky and skidmark equivalents. Yeah, hybrids still might not quite
the "oomph" of the solids, but you have a handful of new vendors making
great strides.
-Tim
Glen Overby wrote:
Hybrids are a lot of fun. But you can't do motor based ejection
systems. So you have to use electronics. And that means (for most
people) ematches and BP. Doug Pratt has nichrome based canisters that
avoid the e-match issue. But you still need BP or Pyrodex and you are
supposed to have a LEUP to use either in a hobby rocket.
lizardqueen wrote:
http://tinyurl.com/ty6sx says you may have 50 pounds for use in antique
firearms which is why http://www.tripoli.org/tmt/LEUP_filing.shtml says
to list BP on your LEUP application. Do a search and you'll come up
with numerous references such as http://www.space-rockets.com/homeland.html
The discussions I've seen about Pyrodex say the situation is the same.
The restrictions on selling it are much less than BP which is why it is
seen in many more retail outlets than BP. But the claim, by people who
have studied the situation much more than I have, is that if you intend
to use it in something other than a firearm then you need a LEUP.
Please don't argue with me about how little sense this makes. I agree
completely. 8(
lizardqueen wrote:
Will,
Thanks for pointing out the discussions about Pyrodex. I was not aware
people were being mislead on the use of Pyrodex without an ATFE
license. Actually, Pyrodex is not covered by Federal Explosives Law.
Below is a statement from the Pyrodex MSDS sheet provided by Hodgdon,
the manufacturer of Pyrodex.
Regulatory Information:
Pyrodex is Extremely Flammable. Pyrodex is not an explosive regulated
by Federal Explosive Law, but may explode if misused. Pyrodex is not
smokeless powder, but is approved to ship (DOT) and store (NFPA) as
such. Pyrodex is not allowed on passenger aircraft, but may be loaded
into ammunition which may be allowed. It may be shipped as a flammable
solid by road, rail, vessel, or cargo only aircraft, or as an explosive
by road, rail or vessel. While Pyrodex contains no nitrocellulose, the
flammable solid proper shipping name is "Smokeless powder for small
arms". DOT classifications follow:
Flammable Solid (see 49 CFR 173.171): Smokeless powder for small arms,
4.1, NA3178, PG I
Explosive: Propellant, solid, 1.3C, UN0499, PG II
John Wickman
Will,
Thanks for pointing out the discussions about Pyrodex. I was not aware
people were being mislead on the use of Pyrodex without an ATFE
license. Actually, Pyrodex is not covered by Federal Explosives Law.
Below is a statement from the Pyrodex MSDS sheet provided by Hodgdon,
the manufacturer of Pyrodex.
Regulatory Information:
Pyrodex is Extremely Flammable. Pyrodex is not an explosive regulated
by Federal Explosive Law, but may explode if misused. Pyrodex is not
smokeless powder, but is approved to ship (DOT) and store (NFPA) as
such. Pyrodex is not allowed on passenger aircraft, but may be loaded
into ammunition which may be allowed. It may be shipped as a flammable
solid by road, rail, vessel, or cargo only aircraft, or as an explosive
by road, rail or vessel. While Pyrodex contains no nitrocellulose, the
flammable solid proper shipping name is "Smokeless powder for small
arms". DOT classifications follow:
Flammable Solid (see 49 CFR 173.171): Smokeless powder for small arms,
4.1, NA3178, PG I
Explosive: Propellant, solid, 1.3C, UN0499, PG II
John Wickman
Thanks, John! I'm happy to have been misinformed and to learn that
Pyrodex is OK for use in rockets without a LUEP! Doug Pratt has some
information at
http://www.pratthobbies.com/info_pages/pyrodex/pyrotest.htm about using
his Nichrome based canisters with Pyrodex. I think that means you can
do a completely LEUP-less high power rocket if you fly a hybrid...
Best wishes,
Will
John Wickman wrote:
People have been using black powder for years to make their parachute
activation device systems. I've seen no posts or discussions of raids,
arrests, or even warnings. Maybe you should ask more questions before
reposting 'discusion advice'?
Will,
Thanks for the link. Doug did a nice job with the video presentation.
As he points out the key is using electrical tape to seal the end of
the Pyrodex P canister. I've used 1/2 " PVC pipe and an end cap on one
end. I cross the open end of the pipe with electrical tape making a
cross on the open end. Then, I put layer around the perimeter of the
open end to hold those two pieces more securely in place. For ignition
I use a 1/2" to 3/4" long piece of 36 gauge NiCr wire. No coating on
the wire, just plain. It is wrapped around the wire and inserted into
the Pyrodex. I use a little wadding to hold the Pyrodex down in the
base of the pipe by the end cap so the powder stays in contact with the
NiCr wire. Works every time.
For homemade, motors with a delay and charge, I use Pyrodex P as well.
Just seal the open end of the ejection charge opening the same way with
electrical tape.
I don't know if it is necessary, but I also add an extra gram of
Pyrodex P from what I would use if going with 4F black powder. I
haven't used black powder in years and never had a problem in over a
hundred flights.
John
Will Marchant wrote:
you think there won't be any international air shipping restrictions on
hybrids (the non pyrotechnic type that is)? I mean its like shipping
plastics. Of course the GSE would be expensive..
--
TAI FU
"lizardqueen" < snipped-for-privacy@gmail.com> wrote in message
Liz,
To make this simple and sweet... YES YES HELL FING YES! Hybrids give
you better performance than solids, and at a FRACTION of the cost, and
NO GOVERNMENT regulation... think about that as your rule over your
lizards!
Lunar
lizardqueen wrote:
Almost always voiced by someone who has not flown hybrids.
IIRC, when reloadable motors first hit the market people said they were
a pain in the rear. Oh, and unreliable too. I rarely see people make a
big deal when an APCP motor spits an igniter or chuffs on the pad. But
if a hybrid fails to launch on the first attempt there is a loud outcry
about how unreliable and complicated they are. FWIW I do failure
analysis on all my flights and the biggest problem I have with hybrids
is getting a complete fill. That's mainly a procedural problem and I'm
getting better every flight. Are hybrids more complex? Sure, who said
rocket science was easy B-)
hybrids. I think the future of AP is too unclear to invest a lot of
money in hardware. I also like the fact that there seems to be no
reasonable limit on the ultimate power you can get from these systems.
I contacted my local club and hopefully I can get them to move on
hybrids, but if they don't I'll probably still invest in my own ground
support. It looks like you can get started with the less expensive
ground support for a few hundred. It is a difficult decision which
system to buy. For those that fly hybrids, which system should I go
with? I'm looking in the I, J, and K class area since I would like to
Cert L2 on a hybrid, buy still fly on L1. Can I use some of the same
ground equipment on different systems with maybe small modifications
such as fittings, adapters? So I guess I'm looking for cost and
versatility in my decision. I'll leave the sparky-smokey things for
later ;-)
Any help will be appreciated since this is a pretty tough choice with
my still limited knowledge.
Alex Mericas wrote:
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