Thanks James,
Great News James! It's great to hear from you.
So what's your preference for L1 - L2 hybrids? Given that LUNAR has
GSE, what would I need to check hybrids out besides the motor and
reload? I guess if I end up going with hypertek, I'll need the ULS
Module 3: GOX/HV Ignition Module? I already have an O2 tank.
I can't find the RATT works website so that concerns me a little, but I
kind of like the pyrogen ignition. How's RATT doing as a company?
Will they still be supporting their motors?
The hypertek motors are attractive, but they do need the high voltage
ignition. As you can tell, I'm still in the fact gathering phase, but
I've kind of hit a wall. Are there any reviews such as pros and cons
of the different systems?
Thanks for all help.
Laura
James L. Mar> Liz,
To give you even more food for thought, check out the yahoo group
hybridrocketmotors
A lot of those folks are doing stuff that is way over my head, but they are
wellspring of advice and encouragement, and the archives are invaluable.
Kevin O
PS> If I were in your position (already L1), knowing what I know now, I'd
probably start with the Contrail 38mm motor set. Motors from G100 to a 45%
J800, reasonable hardware and reload cost, good performance. I used the
38mm set to certify L2.
Laura,
I've flown the Ratt I80 and the Ratt K240. Both nice motors. I also
own(ed) and flew an AeroTech 54mm hybrid, but I sent the flight tank to Gary
for repair about two weeks before the fire in Vegas. Bummer. Gary said he's
going to get me a replacement, and that they're working on getting some
reloads made, but there's a problem getting the little pyro pellet that they
use for their pyro valve. All three of the motors I've flown use APCP grains
that are < 62.5 grams, so no permits involved.
A word of warning... Don't use any of the accelerometer based
electronics in a hybrid powered rocket. Use a baro altimeter. There's a
problem with accelerometers detecting launch with hybrids. Has to do with
the oscillation of the thrust. I'll be using a PerfectFlite MAWD with mine.
I don't have a clue what's up with Ratt Works. He does motors as a
side thing to his machining business, so they may be busy with higher paying
customers. But I'm pretty sure he's still in business down in Monterey.
The thing to keep in mind for the Ratt motors is "build light."
They aren't the thrustiest motors around, but they are very kool, fun to
use, and cheap to fly. Pretty sure Bob has them in stock at
formatting link
Tell him I sent you. Bob's good people. He will know better than I about
continued support for the Ratt motors. Ask him.
I have a bird in construction to use the I80 Ratt, and need to
machine an adapter to fly the K240 in my Comp4 (the K240 is an odd size,
2.5" mmt required. Since the Comp4 has a 75mm mount, making an adapter will
be a piece of cake.) That is coming. I have to concentrate on the M flight
at Snow Ranch for the time being, but both hybrids will fly this season at
the ranch. But I do need to get my Beeline GPS up and running before flying
an M or any of the hybrids. I'm addicted to getting them back.
If you decide to go with the Hypertek motors, no problem. The
AeroPAC trailer is at Richard's shop in Oakland, and I know he'll be more
than happy to bring the GSE out to a launch for use, O2 and high tension
included. So really, all you need is a motor and a bird in which to fly it.
Please let me know if I can be of any assistance in your travels
through the world of rocketry. More than happy to help. Oh, and to answer
your other question, the Ratt K240 would be a killer motor for an L2 cert.
Build a bird, buy a reload, and I'll be happy to loan you the motor and the
GSE. (Standard loaner agreement applies.) Build your bird with a 75mm mount
and a Slimline retainer, and I'll throw in the adapter, too. That way,
venting won't be a problem. My adapter will vent out the bottom. And be sure
to make the booster section long enough (4 feet should do) for the motor.
It's over 3 feet long.
James
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:
> 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
>
formatting link
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:
> > Will Marchant wrote:
> >> 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. > >>
> >
> > 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 Marchant, NAR 13356, Tripoli 10125 L3
> snipped-for-privacy@amsat.org
James,
I'd disagree with you on this one. I've used Gwiz LC & MC flight computers
for every hybrid flight I've made (42 so far) and these are definitely
accelerometer based units. They've worked perfectly every time. The
specified launch detect is simply 2+G for 1/2 second. I like the Gwiz LC
Basic (apogee only deployment) for smaller, low altitude birds, because no
vent holes are required and you have a lot of freedom in mounting the
device.
I understand there historically have been some problems with certain types
of flight computers being affected by high frequency signals generated by
the Hypertek ignition system's spark gap. That was, frankly, before my time,
and obviously not pertinent to all hybrids.
Not a thing wrong with baro based computers-- the MAWD is an excellent
device. Nothing wrong with accelerometer based units either.
Kevin OClassen
James,
Thanks again for the generous help.
I found a hybrid motor group:
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asked the same question regarding the RATT website.
formatting link
the RATT website is being updated and a preview of the new
site can be seen here.
formatting link
(I'm sure that
link will only be valid for a short while.)
I may take your advice on the K240 for L2 cert. I don't know if I'll
pull it off for Snow Ranch, but in the mean time I'll look into the I
class RATTs for the upcoming Snow Ranch launches.
I'm not sure what the "standard loaner agreement" is, but I'm sure it's
reasonable.
Good luck on the M flight sounds exciting.
Oh one more question. Are the grains for these hybrids unique or are
they some what interchangeable?
I'm only concerned with the availability of fuel in the future.
James L. Mar>Please let me know if I can be of any assistance in your travels
Kevin,
Glad to hear you're having success with the GWiz. I'm sure Rob and
Larry would be happy to hear that also. Perhaps I'm a bit over cautious, but
I crashed a bird with a K240 Ratt using an accelerometer. It wasn't a GWiz,
but it didn't live long. It was an AcceloRocket accelerometer. Worked fine
on the J415, but failed to detect on the K240. Talk about depressed. That
was a nice rocket, right up until impact. 8^(
I'll be finding out how well the GWiz will work this winter. Going
to mount the MAWD in the av bay of my Comp4 along side the (2) GWiz units
that are already in there, and see what happens with the K240. (Plenty of
room. I AM a big GWiz fan. Fly with Rob and Larry, the GWiz Partners.
Currently beta testing the new LCX for them. Nice unit.)
James
Laura,
The "standard loaner agreement" is "you break or lose it, you bought
it." Other than that, give it back clean, and no charge. 8^)
Yup, Ratt Works is still there. I don't think there will be a
problem getting grains for any of their motors for the foreseeable future.
You could always make grains for them, but that would invalidate the
certification for the motor, and classify it as Ex. Hybrids will burn just
about anything as a fuel grain.
And of course there's no rush to get to L2. Plenty to learn and lots
of fun to be had flying L1, that's for sure.
Looking forward to seeing you at the ranch. Come on rain! Get that
ranch green!
James
James,
Please allow me to correct myself - there *is* apparently a problem with
some accelerometers and hybrid engines, having to do with sampling rates and
motor 'frequency'. I asked about it over in the yahoo group hybridrockets
and got an excellent explanation, complete with links to more information.
I love this learning curve, and one of these days I'll learn to ask the
questions first.
Kevin O
PS> Thanks for mentioning the LCX. I hadn't visited the GWiz site in a
while, and had not heard of this computer. I have been considering a second
dual-deploy flight computer, and had almost settled on a RocketMotion
Mission Control. The LCX, while not quite as full featured is at a very
attractive price, and GWiz have been very reliable for me, with great
product support. Now I have to try to decide.... :)
Any idea when this will hit the market?
Hey James,
Thanks again. I signed into your webpage so that you have my email.
Would it be ok to take some of the conversation out of RMR? I'll try
not to wear out my welcome, but I do have some specific questions
regarding LUNAR and hybrids and eventually the rest of the group will
probably get bored. I'll start with first of many questions.
(sorry-you kinda asked for it!)
I was looking at the thrust on some of the hybrid motors and they seem
kind of low. Do you have a recommendation on a L1 hybrid that can
safely lift a 5.5-6lb rocket and will be easily supported at Snow
Ranch?
James L. Mar> Laura,
Liz (may I call you, Liz?),
I don't know that you could possibly wear out your welcome here
by asking the questions you are asking.
I, for one, am following your project with interest as I am also
looking at hybrids. If you and the previous respondents don't
mind, I would encourage you to continue on rmr.
But, if you are uncomfortable with how it is going here, please
let us know how things are going as you proceed.
Best wishes and clear skies,
Kevin,
Not sure when it will hit the market, as we're still in the testing
phase. Really, it shouldn't be too far off. But I can say that I like it,
and so far, it has worked quite well. I like being able to program the low
altitude event, and the timer function allowed me to use it as a back-up
unit in my ARLISS M rocket.
James
No problem, Laura. Reach me directly at jmarino1 (at) sbcglobal
(dot) net.
Contrail looks like it has some pretty good numbers for it's motors.
But... Are they CSFM certified for use in Kalifornia? I don't know... But
I'll see what I can find out.
James
Gary, Thanks for the encouragement.
This thread could get pretty long, but if others are interested I am
all for it.
young and dynamic area of rocketry. It's bringing me down the path of
"rocket science" and I've stumbled onto some pretty interesting sites.
Like this one:
formatting link
is a lot to learn and the challenges to using hybrid and the fact
that it seems to be still evolving is exciting.
I'm not rich and the family already thinks I'm nuts for spending so
much time and money on rockets so I want to make a sound purchase.
Luckily, I'm in the area of Livermore California so I will get some
help with GSE from LUNAR. It seems like the GSE is compatible (with
slight variations) with many of the different systems.
James,
I am also looking at the contrails. I've got my eye on the I-333 or
the I-307. Does LUNAR have the GSE for these? It's still unclear to
me what type of GSE is necessary for the contrails. For L2 I will
probably go with the K240. It looks like contrails and RATT use the
same connectors. No?
Anyway- thanks I'll try and look into the CSFM California
Certification.
Thanks again all.
Laura A.K.A lizardqueen
Gary wrote:
Laura,
The GSE for Contrail motors is the same as RATT or any other monotube
hybrid. The only odd requirement is for a 24V ignition source, since the
Contrail motors use a carbon film resistor to initiate their motors, rather
than an igniter or ematch. Most folks swap the resistor out and use an
ematch in its place.
Kevin O
Laura,
All of the monotube motors will use the same GSE as the Ratt. Just
have to be sure we have the right connector to fit the fill tube. And I have
access to many types and sizes of brass fittings for this. So, if the
Contrails are CSFM certified, we're there. 8^)
James
Thanks Kevin,
I'm glad to hear that some folks use ematches. I'm not sure why I'm
resistant to the high voltage ignition (no pun intended) except maybe
it's one more thing to buy and one more new thing to digest. Maybe
I'll warm to the idea eventually.
Kev>
's still back under construction, but their links work to the
different motors and pricing if you click on "Products" at the top..
Their domain expired earlier this year and someone snatched the name
out from under them before they could renew so they lost their primary
website.. The above site is what they're working on to rebuild it..
They're not going anywhere.. I just picked up the H70/I80 casings as
well as the L600/M900 set and they've still got reloads for all of
them.. Dave is a good guy, but this is not their primary business..
They're a very old machine shop (Monterey Machine Products) doing
aerospace parts since the 50's so don't expect them to be picking up
and going anywhere anytime soon..
Laura,
The Contrail motor hardware "combinations" can be confusing. Just FYI, the
I307 and the I333 use the same hardware, just a different reload kit. In
fact, that hardware can be used to make 4 motor combos:
I-307 573NS
I-333 556NS
I-400 432NS
I-290 Sparky 488NS
The I307 is a great motor. A poor-quality video of that motor in a 10lb
rocket can be found at
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