Aerotech or Hypertech Hybrids?
Mike Selfridge
heavy and expensive. Does anyone have any first hand experience they
could share? Any comparisons between Aerotech and Hypertech hybrids?
I have talked with dealers, but they always recommend the brand they
sell, and talk down the competition.
--Mike
John Dunbar
Hello Mike,
What follows is my personal opinion on the existing Hybrid products:
The Aerotech Hybrid is the most straight forward product available on
the commercial market today. It is a self contained system, which can
either be staged or clustered without modification.
You can also use the hybrid commponents on reloads as well! This points
out the inherant versatility in this product. You don't need eloborate
and expensive ground equipment to fly Aerotech Hybrids. They fly off
ANY launch rod you or your local flying club use.
Don't be beguiled by the gimmicky products which exist on the market.
Go for the product which has the greatest flexability, easiest use, and
the most cost effectiveness ... go with the Aerotech Hybrid :)
I hope this helps you in your decision making.
--
John Dunbar
Bill Nelson
: mik...@deltanet.com (Mike Selfridge) wrote:
: >I am interested in the hybrid motors currently available. They seem
: >heavy and expensive. Does anyone have any first hand experience they
: >could share? Any comparisons between Aerotech and Hypertech hybrids?
: >I have talked with dealers, but they always recommend the brand they
: >sell, and talk down the competition.
: >
: >--Mike
: Hello Mike,
: What follows is my personal opinion on the existing Hybrid products:
: The Aerotech Hybrid is the most straight forward product available on
: the commercial market today. It is a self contained system, which can
: either be staged or clustered without modification.
The staging and clustering are the two major advantages.
: You can also use the hybrid commponents on reloads as well! This points
: out the inherant versatility in this product. You don't need eloborate
: and expensive ground equipment to fly Aerotech Hybrids. They fly off
: ANY launch rod you or your local flying club use.
But, you need the reload set. So there is a tradeoff. They are also a lot
harder to prep than the Hypertek product.
: Don't be beguiled by the gimmicky products which exist on the market.
: Go for the product which has the greatest flexability, easiest use, and
: the most cost effectiveness ... go with the Aerotech Hybrid :)
I have both, and like them both. Both have advantages and disadvantages.
The Aerotech will, as John said, fly easily off of any rod - without any
ground support equipment. They can also be clustered or staged. The
negatives are the cost of the reload set - and the complexity of assembly
which is typical of a composite (even slightly more so due to the critical
placement of the igniter).
The Hypertek system only takes minutes to assemble, and can be made ready
to fly again within minutes. Because of the on-pad loading of N2O, any
given oxidizer tank can hold more oxidizer - so you will get more total
impulse out of a given tank size. The negatives are the launch support
equipment that is required and the more complicated launch sequence. The
launcher will work on any pad/rod, but requires assembly.
I think that both have their place. If you are looking for versatility
of case use, and familiar assembly launch sequences, then the Aerotech
system has the edge. If you are looking for max performance, then the
Hypertek system will win out (by about 30% total Isp for any given tank).
Bill
kapl...@hccompare.com
> I am interested in the hybrid motors currently available. They seem
> heavy and expensive. Does anyone have any first hand experience they
> could share? Any comparisons between Aerotech and Hypertech hybrids?
> I have talked with dealers, but they always recommend the brand they
> sell, and talk down the competition.
On a somewhat related note, has anyone seen any data on the performance of
these motors. For a minimal simulation, I need loaded motor mass, fired
motor mass, total impulse, and burn time. I'm looking for a way to get level
2 certification ths spring without the headaches of a LEUP. Before I commit
$$$ to a rocket, motor, altimiter, and GSE, I need a better idea of what
these nifty gadgets will do for me.
Bob Kaplow INTERNET: kapl...@hccompare.com
USPO: HealthCare COMPARE Corp, 5ISD, 3200 Highland Av. Downers Grove, IL 60515
TPC: (708) 241-7919 x5327 ICBM: 41°49'48" North 88°0'51" West
186,000 Miles per second. It's not the law, it's a challenge!
Disclaimer: If this message is caught or killed, the secretary will disavow
any knowledge of my actions. These bits will self destruct in 5 seconds....
Jerry Irvine
> I am interested in the hybrid motors currently available. They seem
> heavy and expensive. Does anyone have any first hand experience they
> could share? Any comparisons between Aerotech and Hypertech hybrids?
> I have talked with dealers, but they always recommend the brand they
> sell, and talk down the competition.
>
> --Mike
They both have horrible power to volume ratios. The Aerotech system
requires no on pad hardware which some consider an advantage and it is
initiated pyrotechnically. Some consider that a disadvantage, but since
all components are Class 1.4s or lower and fully UPS'able there is no
relevent shipping difference.
The Hypertek system is more efficient, has a higher tank loading due to
the loading mechanism design and is thus more energy dense than AT. The
HT system uses a molded thrust chamber and fuel grain thus is cooler
looking, lower cost to make and buy and lower cost to replace parts that
are damaged. The HT system requires the rocket be loaded on the pad,
which some consider a disadvantage and is downright hard to static test.
Overall the HT system is technically better. AT has more dealers, a
larger installed base of combustion chambers as the AT Hybrid uses their
54mm reloadable motor hardware. It will probably be like VHS vs Beta.
You know the HT system is better and has a better growth path. But tons
of people will buy the AT system out of inertia.
Just Jerry
"No comment as to which I have purchased."
--
Jerry Irvine - jjir...@aol.com, jjir...@cyberg8t.com
Box 1242, Claremont, CA 91711 USA ^^^^^^^^
Opinion, the whole thing.
Jack Goff
>In article <4anave$1...@news1.deltanet.com>, mik...@encoreengineering.com wrote:
>> I am interested in the hybrid motors currently available. They seem
snip
>> --Mike
>They both have horrible power to volume ratios. The Aerotech system
>requires no on pad hardware which some consider an advantage and it is
>initiated pyrotechnically. Some consider that a disadvantage, but since
>all components are Class 1.4s or lower and fully UPS'able there is no
>relevent shipping difference.
But the AT system requires cleaning and rebuilding. The HT system
needs neither.
>The Hypertek system is more efficient, has a higher tank loading due to
>the loading mechanism design and is thus more energy dense than AT. The
>HT system uses a molded thrust chamber and fuel grain thus is cooler
>looking, lower cost to make and buy and lower cost to replace parts that
>are damaged. The HT system requires the rocket be loaded on the pad,
>which some consider a disadvantage and is downright hard to static test.
Most (nearly ALL) major launches have the hardware for HT pad setup.
Remember that AT also requires special hardware to launch, like scales
to weigh the NO2 loaded prior to launch.
>Overall the HT system is technically better. AT has more dealers, a
>larger installed base of combustion chambers as the AT Hybrid uses their
>54mm reloadable motor hardware. It will probably be like VHS vs Beta.
>You know the HT system is better and has a better growth path. But tons
>of people will buy the AT system out of inertia.
If you start from scratch, the HT system is cheaper to buy and
launch, especially if you site has the HT launch hardware. No
comparison, in my view.
Jack
John Dunbar
>jjir...@cyberg8t.com (Jerry Irvine) wrote:
>
>>In article <4anave$1...@news1.deltanet.com>, mik...@encoreengineering.com wrote:
>
>>> I am interested in the hybrid motors currently available. They seem
>snip
>>> --Mike
>
>>They both have horrible power to volume ratios. The Aerotech system
>>requires no on pad hardware which some consider an advantage and it is
>>initiated pyrotechnically. Some consider that a disadvantage, but since
>>all components are Class 1.4s or lower and fully UPS'able there is no
>>relevent shipping difference.
>
>But the AT system requires cleaning and rebuilding. The HT system
>needs neither.
>
I don't ming the clean up, matter of fact that is some of the fun with
the reloadable systems. They place you in the position of being responcible
for your rocket's entire mission. It gives the modeler that true rocket
scientist feel.
>>The Hypertek system is more efficient, has a higher tank loading due to
>>the loading mechanism design and is thus more energy dense than AT. The
>>HT system uses a molded thrust chamber and fuel grain thus is cooler
>>looking, lower cost to make and buy and lower cost to replace parts that
>>are damaged. The HT system requires the rocket be loaded on the pad,
>>which some consider a disadvantage and is downright hard to static test.
>
Ok, yes maybe you get more NO2 in the tank, but not all of the grain is
used up. Yes, there are people who are trying to work out ways of
reusing HT grains, but the motor's efficency can also be measured on how
well and what % of grain or propellant is used. Now what follows may come as
a huge shock to some of our readers:
WHEN YOU USE HYBRID MOTORS, YOU DO NOT, I REPEAT DO NOT NEED ANY SPEACIAL
GRAINS OR FUELS TO MAKE THE SYSTEM WORK. INDUSTRIAL PAPER TOWEL ROLLS SOAKED
IN USED MOTOR OIL WILL WORK JUST AS WELL IF NOT BETTER THAN THE SO CALLED
COOL LOOKING HT GRAINS.
As a result of this, you can use the AT system, paper thick paper towel rolls,
and fly on nothing but the price of the NO2! Interesting eh?
>Most (nearly ALL) major launches have the hardware for HT pad setup.
>Remember that AT also requires special hardware to launch, like scales
>to weigh the NO2 loaded prior to launch.
But what if I want to fly alone or with a small group of PRIVATE flyers?
Also, it is a pain to haul those huge heavy tanks around ... sorry but I
personaly want to save my back for old age :)
>
>>Overall the HT system is technically better. AT has more dealers, a
>>larger installed base of combustion chambers as the AT Hybrid uses their
>>54mm reloadable motor hardware. It will probably be like VHS vs Beta.
>>You know the HT system is better and has a better growth path. But tons
>>of people will buy the AT system out of inertia.
>
Ok the above is obviously a blatant bias in favor of HT. Look folks, I'm not
getting any payment or bonuses from Gary or ED. I'm saying the above because
its truth and factual as I know it to be. The HT systems suffers from being
far too technicle. I would rather spend the extra $5 or $10 to get into the
air then battle with ground support setup. Now lets see, I have just driven
for 7 hours to the launch site, and I realy can not wait to spend another 4
to 5 hours for NO2 setup ... OH JOY!
Well the above is a little emotional, so back to basics. The HT system does
have nice features like a screw on grain, but most of it does not get used.
Also, the HT can not be staged! This is a TREMENDOUS weakness in the system.
It CAN NOT BE USED AS A SUSTAINER. It can be used as a booster, but so can
an expendable motor, and a AT motor. So what is the big deal??????
> If you start from scratch, the HT system is cheaper to buy and
>launch, especially if you site has the HT launch hardware. No
>comparison, in my view.
Well alot of people already have in their posession the 54mm casings. All
they need is the NO2 tank, nozzels, thick paper rolls dipped in oil, selinoid,
and they fly for PENNIES! Nope if you understand the hybrid system in general,
you can fly for pennies, then turn around and take your AT system and fly
your reloads. I'm my book, this system is analogous to Mike Tysen fighting
Pee Wee Herman!
>
>Jack
>
>
>
You do have a few good points Jack :)
Hell buy what ever you want, its not my money, and
its still a free country!
--
John Dunbar
Gary C. Rosenfield
>>They are also a lot harder to prep than the Hypertek product.<<
The AeroTech hybrid offers a trade off of somewhat greater
complexity in the motor for a LOT less complexity in the ground
support equipment and set-up procedures.
>>Because of the on-pad loading of N2O, any given oxidizer tank can
hold more oxidizer - so you will get more total impulse out of a
given tank size.<<
This is incorrect. The AeroTech hybrid actually delivers higher
total impulse with less propellant consumption.
>>If you are looking for max performance, then the
Hypertek system will win out (by about 30% total Isp for any given
tank).<<
As I stated in another message, the AeroTech hybrid has the edge in
performance over the competition through higher specific impulse.
--
Gary C. Rosenfield / 7362...@compuserve.com
AeroTech Consumer Aerospace
1955 S. Palm St. * Suite 15 * Las Vegas, Nevada 89104 * USA
Jerry Irvine
Rosenfield <7362...@CompuServe.COM> wrote:
> Bill Nelson wrote:
>
> >>They are also a lot harder to prep than the Hypertek product.<<
>
> The AeroTech hybrid offers a trade off of somewhat greater
> complexity in the motor for a LOT less complexity in the ground
> support equipment and set-up procedures.
>
> >>Because of the on-pad loading of N2O, any given oxidizer tank can
> hold more oxidizer - so you will get more total impulse out of a
> given tank size.<<
>
This is a factual statement regarding Hypertek.
> This is incorrect. The AeroTech hybrid actually delivers higher
> total impulse with less propellant consumption.
>
> >>If you are looking for max performance, then the
> Hypertek system will win out (by about 30% total Isp for any given
> tank).<<
>
Bill mistated a bit here. The Hypertek system has 30% higher total
impulse, not ISP, due to a higher fuel load in a given tank size.
> As I stated in another message, the AeroTech hybrid has the edge in
> performance over the competition through higher specific impulse.
>
Gary minced words a bit by implying that a marginally higher ISP (which is
under debate anyway) is related to the TOTAL IMPULSE comparisons. The ISP
differences are within 5% either way and the Total impulse figures are
allegedly 30% different.
Hypertek claims with some credibility that under optimum conditions its
plastic fuel is a bit more efficient than Aerotech's "cellulose" (read
paper tube) fuel. Neither is optimum as perhaps aluminized HTPB would be.
> --
> Gary C. Rosenfield / 7362...@compuserve.com
> AeroTech Consumer Aerospace
> 1955 S. Palm St. * Suite 15 * Las Vegas, Nevada 89104 * USA
In any case as I said in a previous post Aerotech currently has a
distribution advantage which makes these technical discussions virtually
moot.
Good to see you on rmr Gary!
Jerry Irvine
Mick Ishmael
: : WHEN YOU USE HYBRID MOTORS, YOU DO NOT, I REPEAT DO NOT NEED ANY SPEACIAL
: : GRAINS OR FUELS TO MAKE THE SYSTEM WORK.
: : INDUSTRIAL PAPER TOWEL ROLLS SOAKED
: : IN USED MOTOR OIL WILL WORK JUST AS WELL IF NOT BETTER THAN THE SO CALLED
: : COOL LOOKING HT GRAINS.
: : As a result of this, you can use the AT system,
: : paper thick paper towel rolls,
: : and fly on nothing but the price of the NO2! Interesting eh?
: I wouldn't bet on it, for a couple of reasons.
: First, the rolls would be rather soft, and would probably plug the nozzle.
: The results are unpredictable.
: Second, there is not enough fuel mass there (unless you use a very large
: amount of oil) and burned oil would be a pain to clean up.
: If the rolls are dense enough, then the oil gains you nothing - the rolls
: would be sufficient all by themselves.
: However, you could probably turn a hardwood dowel, and use that as a fuel
: grain.
: Keep in mind that such motor modification violates both TRA and NRA codes.
I think that you could take paper and turn it back to pulp, and 'cast' a
fuel grain with it. <just get a subscription to the local newspaper>One
might even try this with an oxidiser as a fuel for a motor.
not enough Isp?
Jerry Irvine
> In article <4anave$1...@news1.deltanet.com>, mik...@deltanet.com (Mike
Selfridge) writes:
> > I am interested in the hybrid motors currently available. They seem
> > heavy and expensive. Does anyone have any first hand experience they
> On a somewhat related note, has anyone seen any data on the performance of
> these motors. For a minimal simulation, I need loaded motor mass, fired
> motor mass, total impulse, and burn time. I'm looking for a way to get level
Since I do not have any hard data to offer, I will offer this. Based on
total impulse claims and burn time claims of the manufacturer and assuming
the motor weighs approximately double an equivelent expendable motor and
it is twice as long, one can do some fairly accurate simulations.
Jerry
"Nothing is possible until it exists, and then it's certain."
Bill Nelson
: bi...@PEAK.ORG (Bill Nelson) wrote:
: >
: >: WHEN YOU USE HYBRID MOTORS, YOU DO NOT, I REPEAT DO NOT NEED ANY SPEACIAL
: >: IN USED MOTOR OIL WILL WORK JUST AS WELL IF NOT BETTER THAN THE SO CALLED
: >: COOL LOOKING HT GRAINS.
: >
: >: As a result of this, you can use the AT system, paper thick paper towel rolls,
: >: and fly on nothing but the price of the NO2! Interesting eh?
: >I wouldn't bet on it, for a couple of reasons.
: Bill Coulburn RRS Pres flies the paper towel rolls ... no problem!
: It dose not matter what you burn in the pressence of O2 ... it will
: "burn". What matters is the amount of energy released in a given
: time.
Unless you get nozzle clogging, or "grain" separation, I would agree.
... deleted ...
: Bill you have said a few things about tank volume and preping. I suggest
: you read the postings that Gary made a few back ... they are very interesting.
I just did, and responded to one or two. They cleared up a couple of
misconceptions.
: Personally, I will never haul around such equipment just to fly "model"
: rockets.
Me, I like anything that will boost a rocket. That is why I purchased both
sets.
: Now if I were conducting research into casing materials, propellant mixtures,
: or aerodynamics, then I would go through the effort. If its just to launch a
: rocket for the purpose of visual pleasure , then give me a SILVER STREAK! :)
As I have posted before, I enjoy both systems. The Hypertek system is
inovative. The Aerotech system is an excellent adaptation of an existing
motor - something that is seldom accomplished well (if at all).
Bill
Bill Nelson
: Bill Nelson wrote:
: >>They are also a lot harder to prep than the Hypertek product.<<
: The AeroTech hybrid offers a trade off of somewhat greater
: complexity in the motor for a LOT less complexity in the ground
: support equipment and set-up procedures.
Agreed. I made a post listing the pluses and minuses of both systems.
I like them both, for different reasons.
: >>Because of the on-pad loading of N2O, any given oxidizer tank can
: hold more oxidizer - so you will get more total impulse out of a
: given tank size.<<
: This is incorrect. The AeroTech hybrid actually delivers higher
: total impulse with less propellant consumption.
Hm, just be a more efficient nozzle, and higher chamber pressures.
Am I correct?
: >>If you are looking for max performance, then the
: Hypertek system will win out (by about 30% total Isp for any given
: tank).<<
: As I stated in another message, the AeroTech hybrid has the edge in
: performance over the competition through higher specific impulse.
Thanks for the information. I was assuming a similar Isp for both
motors. From what you post, this is obviously not true.
I am glad to see you posting here, Gary. I am sure there are a lot of
misconceptions about both systems that could be cleared up by the
respective manufacturers.
Bill
Bill Nelson
: cg...@scsn.net (Jack Goff) wrote:
: Ok, yes maybe you get more NO2 in the tank, but not all of the grain is
: used up. Yes, there are people who are trying to work out ways of
You get 30% more, which is a very significant amount.
: reusing HT grains, but the motor's efficency can also be measured on how
: well and what % of grain or propellant is used. Now what follows may come as
: a huge shock to some of our readers:
: WHEN YOU USE HYBRID MOTORS, YOU DO NOT, I REPEAT DO NOT NEED ANY SPEACIAL
: GRAINS OR FUELS TO MAKE THE SYSTEM WORK. INDUSTRIAL PAPER TOWEL ROLLS SOAKED
: IN USED MOTOR OIL WILL WORK JUST AS WELL IF NOT BETTER THAN THE SO CALLED
: COOL LOOKING HT GRAINS.
: As a result of this, you can use the AT system, paper thick paper towel rolls,
: and fly on nothing but the price of the NO2! Interesting eh?
I wouldn't bet on it, for a couple of reasons.
First, the rolls would be rather soft, and would probably plug the nozzle.
The results are unpredictable.
Second, there is not enough fuel mass there (unless you use a very large
amount of oil) and burned oil would be a pain to clean up.
If the rolls are dense enough, then the oil gains you nothing - the rolls
would be sufficient all by themselves.
However, you could probably turn a hardwood dowel, and use that as a fuel
grain.
Keep in mind that such motor modification violates both TRA and NRA codes.
: >Most (nearly ALL) major launches have the hardware for HT pad setup.
: >Remember that AT also requires special hardware to launch, like scales
: >to weigh the NO2 loaded prior to launch.
: But what if I want to fly alone or with a small group of PRIVATE flyers?
Then you do what Jim and I did, buy your own system.
: Also, it is a pain to haul those huge heavy tanks around ... sorry but I
: personaly want to save my back for old age :)
You do not have to use such large tanks. Both small oxygen and N2O tanks
are available.
: Ok the above is obviously a blatant bias in favor of HT. Look folks, I'm not
: getting any payment or bonuses from Gary or ED. I'm saying the above because
: its truth and factual as I know it to be. The HT systems suffers from being
: far too technicle. I would rather spend the extra $5 or $10 to get into the
: air then battle with ground support setup. Now lets see, I have just driven
: for 7 hours to the launch site, and I realy can not wait to spend another 4
: to 5 hours for NO2 setup ... OH JOY!
You can put the Hypertek pad together faster than you can prep an Aerotech
motor, by far. It takes me less than 5 minutes, once the bottles are in
place, and I have had little experience. And it only takes a minute to
prep the Hypertek motor.
In fairness to Aerotech, I tend to "mostly prep" my casings ahead of time.
If this is done with the Aerotech Hybrid, then it only takes about 10
minutes to chill and fill the N2O tank by weight.
In both cases, the rest of the rocket prep takes far longer than setup of
either system.
: Well the above is a little emotional, so back to basics. The HT system does
: have nice features like a screw on grain, but most of it does not get used.
: Also, the HT can not be staged! This is a TREMENDOUS weakness in the system.
: It CAN NOT BE USED AS A SUSTAINER. It can be used as a booster, but so can
: an expendable motor, and a AT motor. So what is the big deal??????
Once the system is set up, it only takes minutes to have the motor ready for
flight again. There is NO cleanup of the motor, as there is no casing to
clean.
Bill
Gary C. Rosenfield
>>The Hypertek system is more efficient, has a higher tank loading
due to the loading mechanism design and is thus more energy dense
than AT.<<
The AeroTech standard hybrid motor delivers up to 29% more total
impulse with LESS propellant than the competition (800 vs. 620 N-sec
in high-thrust mode). The EFX hybrid reload delivers up to 76% more
total impulse with about the same propellant load (1090 vs. 620
N-sec). Reason? Much higher delivered Isp.
John Dunbar
>John Dunbar (jdu...@csd.sgi.com) wrote:
>: cg...@scsn.net (Jack Goff) wrote:
>
>
>
>: a huge shock to some of our readers:
>
>: WHEN YOU USE HYBRID MOTORS, YOU DO NOT, I REPEAT DO NOT NEED ANY SPEACIAL
>: GRAINS OR FUELS TO MAKE THE SYSTEM WORK. INDUSTRIAL PAPER TOWEL ROLLS SOAKED
>: IN USED MOTOR OIL WILL WORK JUST AS WELL IF NOT BETTER THAN THE SO CALLED
>: COOL LOOKING HT GRAINS.
>
>: As a result of this, you can use the AT system, paper thick paper towel rolls,
>: and fly on nothing but the price of the NO2! Interesting eh?
>
Bill Coulburn RRS Pres flies the paper towel rolls ... no problem!
It dose not matter what you burn in the pressence of O2 ... it will
"burn". What matters is the amount of energy released in a given
time.
>
>First, the rolls would be rather soft, and would probably plug the nozzle.
>The results are unpredictable.
>
>Second, there is not enough fuel mass there (unless you use a very large
>amount of oil) and burned oil would be a pain to clean up.
>
>If the rolls are dense enough, then the oil gains you nothing - the rolls
>would be sufficient all by themselves.
>
>However, you could probably turn a hardwood dowel, and use that as a fuel
>grain.
>
>Keep in mind that such motor modification violates both TRA and NRA codes.
>
>: >Most (nearly ALL) major launches have the hardware for HT pad setup.
>: >Remember that AT also requires special hardware to launch, like scales
>: >to weigh the NO2 loaded prior to launch.
>
>: But what if I want to fly alone or with a small group of PRIVATE flyers?
>
>Then you do what Jim and I did, buy your own system.
>
>: Also, it is a pain to haul those huge heavy tanks around ... sorry but I
>: personaly want to save my back for old age :)
>
>You do not have to use such large tanks. Both small oxygen and N2O tanks
>are available.
>
>: Ok the above is obviously a blatant bias in favor of HT. Look folks, I'm not
>: getting any payment or bonuses from Gary or ED. I'm saying the above because
>: its truth and factual as I know it to be. The HT systems suffers from being
>: far too technicle. I would rather spend the extra $5 or $10 to get into the
>: air then battle with ground support setup. Now lets see, I have just driven
>: for 7 hours to the launch site, and I realy can not wait to spend another 4
>: to 5 hours for NO2 setup ... OH JOY!
>
>You can put the Hypertek pad together faster than you can prep an Aerotech
>motor, by far. It takes me less than 5 minutes, once the bottles are in
>place, and I have had little experience. And it only takes a minute to
>prep the Hypertek motor.
>
>In fairness to Aerotech, I tend to "mostly prep" my casings ahead of time.
>If this is done with the Aerotech Hybrid, then it only takes about 10
>minutes to chill and fill the N2O tank by weight.
>
>In both cases, the rest of the rocket prep takes far longer than setup of
>either system.
>
>: Well the above is a little emotional, so back to basics. The HT system does
>: have nice features like a screw on grain, but most of it does not get used.
>: Also, the HT can not be staged! This is a TREMENDOUS weakness in the system.
>: It CAN NOT BE USED AS A SUSTAINER. It can be used as a booster, but so can
>: an expendable motor, and a AT motor. So what is the big deal??????
>
>Once the system is set up, it only takes minutes to have the motor ready for
>flight again. There is NO cleanup of the motor, as there is no casing to
>clean.
>
>Bill
Bill you have said a few things about tank volume and preping. I suggest
you read the postings that Gary made a few back ... they are very interesting.
Personally, I will never haul around such equipment just to fly "model"
rockets.
Now if I were conducting research into casing materials, propellant mixtures,
or aerodynamics, then I would go through the effort. If its just to launch a
rocket for the purpose of visual pleasure , then give me a SILVER STREAK! :)
--
John Dunbar
Dave Oback
(used thing you chuck out when the towl runs out) and putting
it in some motor oil "for a short time" so that the oil will
continue to penitrate the core after the dipping (won't be
dripping wet when used).
Dave O.
------------------------------------------------------------------------------
Just a thought from Dave Oback -> (mr...@LunaCity.com)
LunaCity BBS - Mountain View, CA - 415 968 8140
Gary C. Rosenfield
>>Since I do not have any hard data to offer, I will offer this.
Based on total impulse claims and burn time claims of the
manufacturer and assuming the motor weighs approximately double an
equivelent expendable motor and it is twice as long, one can do some
fairly accurate simulations.<<
The standard paper-fueled RMS/Hybrid (2, 3 or 4-jet) is about 50%
heavier than the equivalent power solid reload motor (say a loaded
J275). The EFX Hybrid is only about 16% heavier than the equivalent
solid (in this case a J415).
Your length estimates are correct. BTW, Anyone wanting additional
specs. on the RMS/Hybrid can obtain a catalog by writing to the
address below.
Gary C. Rosenfield
>>Bill mistated a bit here. The Hypertek system has 30% higher
total impulse, not ISP, due to a higher fuel load in a given tank
size.<<
The AeroTech motor has the higher total impulse, not the other way
around.
>>Gary minced words a bit by implying that a marginally higher ISP
(which is under debate anyway) is related to the TOTAL IMPULSE
comparisons. The ISP differences are within 5% either way and the
Total impulse figures are allegedly 30% different.<<
Nope. Both Isp AND total impulse of the RMS/Hybrid are significantly
higher.
>>Hypertek claims with some credibility that under optimum
conditions its plastic fuel is a bit more efficient than Aerotech's
"cellulose" (read paper tube) fuel. Neither is optimum as perhaps
aluminized HTPB would be.<<
Actually, cellulose is pretty optimum for motors of this size.
Hydrocarbons have a 5% higher THEORETICAL Isp, but burn less
efficiently in these small chambers.
Jerry Irvine
In article <4atnth$i...@odo.PEAK.ORG>, bi...@PEAK.ORG (Bill Nelson) wrote:
> John Dunbar (jdu...@csd.sgi.com) wrote:
> : cg...@scsn.net (Jack Goff) wrote:
>
> : Ok, yes maybe you get more NO2 in the tank, but not all of the grain is
> : used up. Yes, there are people who are trying to work out ways of
>
> You get 30% more, which is a very significant amount.
>
May I say VERY significant.
> : reusing HT grains, but the motor's efficency can also be measured on how
> : well and what % of grain or propellant is used. Now what follows may
come as
> : a huge shock to some of our readers:
>
And what follows does not logically follow from your prefacing factual
statement.
> : WHEN YOU USE HYBRID MOTORS, YOU DO NOT, I REPEAT DO NOT NEED ANY SPEACIAL
> : GRAINS OR FUELS TO MAKE THE SYSTEM WORK. INDUSTRIAL PAPER TOWEL ROLLS
SOAKED
> : IN USED MOTOR OIL WILL WORK JUST AS WELL IF NOT BETTER THAN THE SO CALLED
> : COOL LOOKING HT GRAINS.
>
> : As a result of this, you can use the AT system, paper thick paper
towel rolls,
> : and fly on nothing but the price of the NO2! Interesting eh?
>
Well you "could", but efficiency would suffer even more. Let's see all of
the penalties you would add:
30% less "oxidizer" loading due to selecting the AT system to begin with.
5% more "claimed" ISP, based on an undamped Air Force Test.
20% less ISP by using a less dense paper towel tube, assuming you layered
it sufficiently to withstand the burning time of course.
10% more weight due to the combustion chamber being aluminum instead of plastic
$80.00 more cost since the combustion chamber is RMS and extra cost
Come to think of it I knew there was a reason I like Korey.
> I wouldn't bet on it, for a couple of reasons.
>
> First, the rolls would be rather soft, and would probably plug the nozzle.
> The results are unpredictable.
>
> Second, there is not enough fuel mass there (unless you use a very large
> amount of oil) and burned oil would be a pain to clean up.
>
> If the rolls are dense enough, then the oil gains you nothing - the rolls
> would be sufficient all by themselves.
>
> However, you could probably turn a hardwood dowel, and use that as a fuel
> grain.
>
That would actually work.
> Keep in mind that such motor modification violates both TRA and NRA codes.
>
The TRA code violates the TRA code. I would be more concerned with the
NAR code personally.
> : >Most (nearly ALL) major launches have the hardware for HT pad setup.
> : >Remember that AT also requires special hardware to launch, like scales
> : >to weigh the NO2 loaded prior to launch.
>
NOTE: This is probebly the main thing people should pay attention to in
this post. It specifies an availabity of a major cost savings feature of
the HT system. Existing availability of all the stuff for launch. Bring
your rocket, motor, a couple of plastic fuel grains and show up and
launcch, just as invisioned by the "dragonmaster".
> : But what if I want to fly alone or with a small group of PRIVATE flyers?
>
> Then you do what Jim and I did, buy your own system.
>
> : Also, it is a pain to haul those huge heavy tanks around ... sorry but I
> : personaly want to save my back for old age :)
>
> You do not have to use such large tanks. Both small oxygen and N2O tanks
> are available.
>
I am curious how much these are.
> : Ok the above is obviously a blatant bias in favor of HT. Look folks,
I'm not
No kidding. But not for incideous reasons at all.
> : getting any payment or bonuses from Gary or ED. I'm saying the above
because
> : its truth and factual as I know it to be. The HT systems suffers from
being
> : far too technicle. I would rather spend the extra $5 or $10 to get into the
Should I berate you for being a "technicle newbie"? That might be a
technical foul.
> : air then battle with ground support setup. Now lets see, I have just
driven
> : for 7 hours to the launch site, and I realy can not wait to spend another 4
> : to 5 hours for NO2 setup ... OH JOY!
>
> You can put the Hypertek pad together faster than you can prep an Aerotech
> motor, by far. It takes me less than 5 minutes, once the bottles are in
I consider this a BIG issue myself to the point of saying, "expendables rule!"
> place, and I have had little experience. And it only takes a minute to
> prep the Hypertek motor.
>
> In fairness to Aerotech, I tend to "mostly prep" my casings ahead of time.
> If this is done with the Aerotech Hybrid, then it only takes about 10
> minutes to chill and fill the N2O tank by weight.
>
> In both cases, the rest of the rocket prep takes far longer than setup of
> either system.
>
> : Well the above is a little emotional, so back to basics. The HT system does
> : have nice features like a screw on grain, but most of it does not get used.
> : Also, the HT can not be staged! This is a TREMENDOUS weakness in the
system.
Let me add static testing to that list and HT is working to offer a
solution to both issues in V2.0 systems for later release probably
tailored to those missions specifically. This is the tradeoff for
non-pyrotechnic operation and "DOT immunity" (sm-Jerry Irvine).
> : It CAN NOT BE USED AS A SUSTAINER. It can be used as a booster, but so can
> : an expendable motor, and a AT motor. So what is the big deal??????
>
> Once the system is set up, it only takes minutes to have the motor ready for
> flight again. There is NO cleanup of the motor, as there is no casing to
> clean.
>
Well one could say that for an expendable as well :)
> Bill
Jerry Irvine
"Do onto others as you would have them do onto you."
Louwers
: Hypertek claims with some credibility that under optimum conditions its
: plastic fuel is a bit more efficient than Aerotech's "cellulose" (read
: paper tube) fuel. Neither is optimum as perhaps aluminized HTPB would be.
If you do the calculations, you will find that the difference between HTPB/AL
and HTPB is very small. Taking into acount that the AL will have a worse
combustion efficiency, pure HTPB is probably the best fuel to have (except
for PE of course).
--
Jeroen Louwers
lou...@pml.tno.nl / \
|N|
|E|
|R|
/|O|\
/_|_|_\
Jerry Irvine
> I think that you could take paper and turn it back to pulp, and 'cast' a
> fuel grain with it. <just get a subscription to the local newspaper>One
> might even try this with an oxidiser as a fuel for a motor.
>
> not enough Isp?
You could use this in your AT hybrid with no problems and a boost in
delivered ISP.
Jerry
Konrad Hambrick
<kapl...@hccompare.com> wrote:
>In article <4anave$1...@news1.deltanet.com>, mik...@deltanet.com (Mike Selfridge) writes:
>> I am interested in the hybrid motors currently available. They seem
>> heavy and expensive. Does anyone have any first hand experience they
>> I have talked with dealers, but they always recommend the brand they
>> sell, and talk down the competition.
>
>these motors. For a minimal simulation, I need loaded motor mass, fired
>motor mass, total impulse, and burn time. I'm looking for a way to get level
>$$$ to a rocket, motor, altimiter, and GSE, I need a better idea of what
>these nifty gadgets will do for me.
Bob --
Here are thrust curves I measured from the Hypertek Hybrid
Beta Test Manual to aid in my designing a test vehicle.
Known Gotya's:
- Data is based on my direct measurements from the
manual page ( one run -- not averaged ). I ran a
table of linear data thru an awk program to convert
to Seconds and Newtons which accounts for the strange
increments and precisions of the values in the tables.
- I do not know actual fuel consumption for the
three orifices -- only Hypertek's published oxidizer
weight and the differential weight of the grain before
and after flight on the 0.076" orifice.
- I picked the abbreviations HT076, HT098 and HT125 so
as not to conflict with existing thrust curves in
rasp.eng ( from sunsite .) I abbreviated Hypertek
as HTek so the rasp output would align correctly ( I
hope that is ok with the hypertek folks ;-)
Be this as it may, I think the thrust curves are close enough
for guv'ment work ;-)
What a fun motor to fly. I am saving up to buy the AT system
as well but for now, I like getting 800 NSec of IT for $23.008;-)
Anybody have the AT curves ?
Have Fun!
-- kjh
;;;;;;;;;;;;;;;;;;;;;;;;;;;; Cut Here ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
; Thrust Curves Measured by kjh From Hypertek Beta Test Manual
HT076 54 622 0 0.5579 1.4000 HyTek
0.001 515.62
0.042 521.21
0.084 519.81
0.096 162.09
0.217 171.87
0.229 178.86
0.433 183.05
0.608 178.16
0.734 180.26
1.017 187.24
3.731 143.93
3.930 128.56
4.237 75.46
4.478 55.89
6.741 0.00
;Total Impulse 800.14 (N-Sec)
;Avg Thrust: 118.70 (N)
;
; Thrust Curves Measured by kjh From Hypertek Beta Test Manual
HT098 54 622 0 0.5579 1.4000 HyTek
0.001 536.58
0.030 540.77
0.120 257.11
0.445 262.70
0.831 248.73
1.180 251.52
2.119 224.97
2.383 206.81
2.769 96.42
3.226 41.92
4.032 0.00
;Total Impulse 702.23 (N-Sec)
;Avg Thrust: 174.15 (N)
;
; Thrust Curves Measured by kjh From Hypertek Beta Test Manual
HT125 54 622 0 0.5579 1.4000 HyTek
0.001 598.06
0.030 600.86
0.120 388.46
0.265 364.71
0.602 357.72
1.324 278.07
1.818 121.57
2.046 68.47
2.395 30.74
2.793 8.38
3.563 0.00
;Total Impulse 608.09 (N-Sec)
;Avg Thrust: 170.67 (N)
;;;;;;;;;;;;;;;;;;;;;;;;;;;; Cut Here ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
--
------------------------------------------------------------
Konrad J. Hambrick | email: kon...@netcom.com |
310 Third Ave - Suite C21 | work: (619) 585 8611 |
Chula Vista, CA 91910 | home: (619) 423-4451 |
John Dunbar
Bill Coulburn had me realize that the AT system is really a "tribrid"
when you think about it. You gain ISP from the oxidiser in the grains
themselves. The HT system does not currently have this ability?
--
John Dunbar
William
Bill Coulburn had me realize that the AT system is really a "tribrid"
when you think about it. You gain ISP from the oxidiser in the grains
themselves. The HT system does not currently have this ability?
What oxidizer? I thought the Aerotech hybrid grains were straight cardboard,
more or less. You weren't counting the oxygen in cellolose as an oxidizer,
were you?
BillW
Bo Viger
: [John Dunbar Says]
I should let Gary answer this, but when I visited his facility in Las Vegas
just before their hybrid beta program started shipping, he pointed out the
increase in performance due to the oxidizer already contained in the
cellulose. I don't remember the specific numbers he quoted, but the bonus
in oxidizer plus the inexpensive nature of cellulose makes it an ideal
choice. (not that other's don't exist)
Bo
--
_____________________________________________________________________________
Tripoli Rocky Mountains
\|/ /\
-O- /\ /~~\ /\ Bo Viger - Tripoli #1864 voice: (970) 229-6787
/|\/~~\/ \/~~\/\ Hewlett-Packard Company fax: (970) 229-4947
/ \ / /~~\ Fort Collins, Colorado email: b...@fc.hp.com
__/______\__/___/____\_______________________________________________________
Never precede any action with a statement MORE predictive than, "Watch this".
Mark Johnson
> [John Dunbar Says]
> Bill Coulburn had me realize that the AT system is really a "tribrid"
> when you think about it. You gain ISP from the oxidiser in the grains
> themselves. The HT system does not currently have this ability?
>What oxidizer? I thought the Aerotech hybrid grains were straight cardboard,
>more or less. You weren't counting the oxygen in cellolose as an oxidizer,
>were you?
The new "EFX" hybrid reload kits include a single 62.5 gram White Lightning AP
slug in addition to the cardboard. Gary R. (who has been on here of late) says
that the combined Isp of the reload is increased by about 25% by the addition
of AP to the fuel mix. I have no reason to doubt it; the chemistry looks
plausible enough.
...mind you, I'm not speaking for AeroTech, just a customer repeating what
he's heard from them...
=============
Mark Johnson USnail: Symbios Logic, Inc
E-mail: Mark.J...@symbios.com OEM RAID Business Team
Voice: (316) 636-8189 [V+654-8189] 3718 N. Rock Rd.
Visit our web page: http://www.symbios.com Wichita, KS 67226
Jerry Irvine
<jdu...@csd.sgi.com> wrote:
> Hi,
>
> Bill Coulburn had me realize that the AT system is really a "tribrid"
> when you think about it. You gain ISP from the oxidiser in the grains
I challenge you to weigh or even calculate the WEIGHT of the oxidizer in
those paper towel rolls (ha ha).
> themselves. The HT system does not currently have this ability?
>
> --
> John Dunbar
Another BENEFIT of the HT system. Higher density impulse.
Just Jerry
"It's like taking candy from a baby.
Have you ever taken candy from a baby?"
Jerry Irvine
(William ) wrote:
> [John Dunbar Says]
> Bill Coulburn had me realize that the AT system is really a "tribrid"
> when you think about it. You gain ISP from the oxidiser in the grains
> themselves. The HT system does not currently have this ability?
>
> What oxidizer? I thought the Aerotech hybrid grains were straight cardboard,
> more or less. You weren't counting the oxygen in cellolose as an oxidizer,
> were you?
>
> BillW
Yes he was!
Duh.
Jerry
John Dunbar
>In article <BILLW.95D...@puli.cisco.com>, bi...@puli.cisco.com
>(William ) wrote:
>
>> [John Dunbar Says]
>> Bill Coulburn had me realize that the AT system is really a "tribrid"
>> when you think about it. You gain ISP from the oxidiser in the grains
>> themselves. The HT system does not currently have this ability?
>>
>> What oxidizer? I thought the Aerotech hybrid grains were straight cardboard,
>> more or less. You weren't counting the oxygen in cellolose as an oxidizer,
>> were you?
>>
>> BillW
>
>Yes he was!
>
>Duh.
>
>Jerry
>
>--
>Jerry Irvine - jjir...@aol.com, jjir...@cyberg8t.com
>Box 1242, Claremont, CA 91711 USA ^^^^^^^^
>Opinion, the whole thing.
--
John Dunbar
John Dunbar
>In article <4b80n7$8...@gazette.engr.sgi.com>, John Dunbar
><jdu...@csd.sgi.com> wrote:
>
>> Hi,
>>
>> when you think about it. You gain ISP from the oxidiser in the grains
>
>those paper towel rolls (ha ha).
>
>>
>> John Dunbar
>
>Another BENEFIT of the HT system. Higher density impulse.
>
>Just Jerry
>
>"It's like taking candy from a baby.
>Have you ever taken candy from a baby?"
>
>Jerry Irvine - jjir...@aol.com, jjir...@cyberg8t.com
>Box 1242, Claremont, CA 91711 USA ^^^^^^^^
>Opinion, the whole thing.
Jerry, Bill has used wood, paper, even candy. I the presence of
oxygen, almost every element and/or substance combines or burns.
For Christmas, I'm buying myself and Aerotech Hybrid system, and
a set of Rush Limbaugh's ties. Merry Christmas.
--
John Dunbar
Mr Midea
>Subject: Re: Aerotech or Hypertech Hybrids?
>From: bi...@puli.cisco.com (William )
>Date: 20 Dec 1995 13:17:44 GMT
>
> [John Dunbar Says]
> Bill Coulburn had me realize that the AT system is really a "tribrid"
> when you think about it. You gain ISP from the oxidiser in the
grains
> themselves. The HT system does not currently have this ability?
>
>What oxidizer? I thought the Aerotech hybrid grains were straight
cardboard,
>more or less. You weren't counting the oxygen in cellolose as an
oxidizer,
>were you?
>
>BillW
The "Preheater" is a std HTPB/AP grain albeit very small
Mr. MIdea
Dave Oback
> jjir...@cyberg8t.com (Jerry Irvine) wrote:
> >In article <BILLW.95D...@puli.cisco.com>, bi...@puli.cisco.com
> >(William ) wrote:
> >
> >> [John Dunbar Says]
> >> Bill Coulburn had me realize that the AT system is really a "tribrid"
> >> when you think about it. You gain ISP from the oxidiser in the grains
> >> themselves. The HT system does not currently have this ability?
> >>
> >> What oxidizer? I thought the Aerotech hybrid grains were straight cardboa
> >> more or less. You weren't counting the oxygen in cellolose as an oxidizer
> >> were you?
The Hypertek motors burn more as a "mono fuel" than a hybrid that
is, the oxidizer breaks up in the chamber (into N and O) this
gives oxygen to burn the plastic grain, only problem is that
the grain is so short that most of the conbustion products get
burned outside the motor (big flame, no added ISP). Bill C.
checked the numbers and showed that 600Ns could be given by
decomposing the amount of N2O used. N2O needs to be heated to
around 550 degries F. to decompose. This is were the burning
plastic comes in (heats up the N2O into decomposition, AKA
catalyst)
H2O2 does not need much heat to decompose (a room temp. catalyst
does very well (like platnum)) H2O2 works as a better monofuel
than N2O as well.
There are turbine starters for helicopters (for cold weather)
that use N2O and a exspansion chamber and no fuel grain (momo-
propelant gas-gen). The name for it sounds like "micro-neek"
(can't remember the right spelling for it).
Please look up the subject before you say it's not so, thanks.
Kelly Mills
How about N2O4?
William
first, with a technically innovative product. Aerotech came in second
with a less technically interesting product, but a better marketing story.
BillW
Bill Nelson
: The Hypertek motors burn more as a "mono fuel" than a hybrid that
: is, the oxidizer breaks up in the chamber (into N and O) this
: gives oxygen to burn the plastic grain, only problem is that
: the grain is so short that most of the conbustion products get
: burned outside the motor (big flame, no added ISP). Bill C.
: checked the numbers and showed that 600Ns could be given by
: decomposing the amount of N2O used. N2O needs to be heated to
: around 550 degries F. to decompose. This is were the burning
: plastic comes in (heats up the N2O into decomposition, AKA
: catalyst)
This whole paragraph is silly. For one thing, the decomposition of
N2O is endothermic - so you would NOT get any ISP from it. There is
a small amount of thrust produced by the vaporization of the N2O,
but it is small compared to the thrust produced by the burning of
the fuel grain.
The combustion chamber of the Hyptertek motor is slightly shorter
than Aerotech's, but I can guarantee that most of the burning goes
on inside the motor. If what you say were true, then the Hypertek
motor would have a very thick cloud of black smoke behind it, which
is not the case.
The plastic is the fuel - it is NOT a catalyst. A catalyst is not
used up.
: H2O2 does not need much heat to decompose (a room temp. catalyst
: does very well (like platnum)) H2O2 works as a better monofuel
: than N2O as well.
Sure, but N2O is NOT a monofuel - regardless of what you believe.
: There are turbine starters for helicopters (for cold weather)
: that use N2O and a exspansion chamber and no fuel grain (momo-
: propelant gas-gen). The name for it sounds like "micro-neek"
: (can't remember the right spelling for it).
: Please look up the subject before you say it's not so, thanks.
I suspect that they either just let the N2O turn to vapor by reducing
the pressure, or use a heater to augment this natural vaporization.
This is far from the N2O acting as a monopropellant, as it would NOT
break down into N2 and O2.
Bill
LarryC
Aerotech and Hypertek hybrids. I got the impression that the Hypertek is
much easier to use, and that it may have an extra margin of safety over
the Aerotech, but that somewhat bigger Aerotechs are available.
-Larry (All I know is what I read in HPR) Curcio
William
I don't have any problem believing that the Aerotech (machined?) nozzles
lead to a higher Isp than the Hypertech "moulded in" nozzel.
BillW
GRosenfiel
>>This whole paragraph is silly. For one thing, the decomposition of
N2O is endothermic - so you would NOT get any ISP from it. There is
a small amount of thrust produced by the vaporization of the N2O,
but it is small compared to the thrust produced by the burning of
the fuel grain.<<
Actually, N2O has a positive heat of formation, about +15 to +17
Kcal/mole, as I recall, so it actually gives off energy as it decomposes.
Not sure if it is enough to act as a viable monoprop, though.
>>If what you say were true, then the Hypertek
motor would have a very thick cloud of black smoke behind it, which
is not the case.<<
I'd suggest that you take a look at their ad photos again. <g>
***********************************************************
Caution: My lack of response to any particular message should not be
construed as agreement with its contents.
Any questions?
***********************************************************
Gary C. Rosenfield
AeroTech, Inc.
1955 S. Palm St., Suite 15
Las Vegas, NV 89104 USA
(702) 641-2301 (Ph), (702) 641-1883 (Fax)
73624,2...@compuserve.com
Bill Nelson
: Actually, N2O has a positive heat of formation, about +15 to +17
: Kcal/mole, as I recall, so it actually gives off energy as it decomposes.
: Not sure if it is enough to act as a viable monoprop, though.
Thanks for the correction. I doubt seriously if it would be enough.
It might be enough to function as a moderate volume gas generator.
: >>If what you say were true, then the Hypertek
: motor would have a very thick cloud of black smoke behind it, which
: is not the case.<<
: I'd suggest that you take a look at their ad photos again. <g>
There is some black smoke - as I would expect. Part of that is due
to the nozzle being composed of fuel, rather than a non-reactive
ablative substance. How much is due to this is something that I
cannot say.
Thanks for the input, Gary. I hope to see you at the Spring launch
at Pine Mountain.
Bill
GRosenfiel
>>There is some black smoke - as I would expect. Part of that is due
to the nozzle being composed of fuel, rather than a non-reactive
ablative substance. How much is due to this is something that I
cannot say.<<
The nozzle material is a glass or silica filled phenolic--a good ablative.
From my observation, their nozzle normally shows little, if any,
significant erosion. OTOH, AeroTech's hybrid nozzle usually has
considerable erosion, possibly due to higher chamber temp. and pressure.
Gary C. Rosenfield
AeroTech, Inc. * 1955 S. Palm St., Suite 15
Las Vegas, NV * 89104 * USA
(702) 641-2301 (Ph) * (702) 641-1883 (Fax)
73624,2...@compuserve.com/grose...@aol.com