What keeps you from flying hybrids/What needs to be improved?

[edwardw]

So, just wanting a thought on why people don't fly hybrids and what they would like to see that would make them more attractive. I know some people will be immature, but let's try to be civil.


Edward

 

[wwattles]

I currently don't fly hybrids because my club doesn't have any GSE, and flyers have to provide their own. With that in mind, I don't have the space to store any equipment in my little apartment. Heck, I get nasty looks from my wife whenever I bring home another LPR kit or a mailing tube from work!

WW

 

[fyrechaser]

I've been thinking about it very hard lately. The thing that has been holding me back is the GSE. Expensive!

I hear there is a new motor manufacturer though that is promising some new user friendly motor systems J thru M. No GOX or pyro for ignition, we'll see.
I believe the name is Contrail Rockets.

https://www.contrailrockets.com/

 

[edwardw]

GSE can be expensive. Most bigger clubs will have it for you - or you can probably find a group of fliers willing to split the cost. Last time I checked you could get a 75lb bottle of nitrous w/25 year tank lease and filled out the door for about $500. Then you have to add onto that your fill system. But in that you have 75 lbs of nitrous which is quite a lot. I have both a 20lb travel bottle of nitrous as well as a 75 tank that I fill my 20 lb from. As for the initial jump in, it isn't that bad.

Edward

 

[DynaSoar]

Originally posted by edwardw
So, just wanting a thought on why people don't fly hybrids and what they would like to see that would make them more attractive. I know some people will be immature, but let's try to be civil.

1. High pressure GSE/tank too dangerous
2. Requires pyro ejection
3. Ignition system too complex

Make them semi-self contained like the new limited reloadables from AT, with a replaceable grain and gas cartridge, a bullet proof internal charging valve and case, integral burst disk/heater/igniter, and a gas powered ejection system that runs off an apogee detector, and you've got something anyone can use.

There's nothing inherent in plastic/wax/etc. and nitrous that makes it require HPR certification, it's the state of the designs so far. I stress "so far". The designs that have been produced were made for those with the technical expertise to use them. I believe the designs could be evolved to the point where they're easy and safe enough for anyone to use.

 

[ContrailRockets]

Originally posted by fyrechaser
I've been thinking about it very hard lately. The thing that has been holding me back is the GSE. Expensive!

I hear there is a new motor manufacturer though that is promising some new user friendly motor systems J thru M. No GOX or pyro for ignition, we'll see.
I believe the name is Contrail Rockets.

https://www.contrailrockets.com/

Yes, this is True fyrechaser...

We are currently a certified motor manufacture and have eliminated a large portion and hastle which Ground Support usually entails. We have eliminated the need for GOX, or LOX, which also eliminates the extra solenoid required for GOX Ignition. The Steel Wool is not used in our motors. The often used "Preheater Grain" which has been popularized by Ratt Works has also been eliminated in our motors completly. This avoids the need for motors to be shipped hazardous, or require any type of permits.

The required GSE for our motors is a Nitrous Bottle, Solenoids, Battery and Electronics to open solenoid. There is of course a few other connecting pieces, but they are minimal, and fairly small. Not Including the Nitrous Bottle, our GSE will easily fit into a filing box, with room to spare for grease, towels, tools etc. The upfront price of GSE can be expensive. This is true. But you have to remember how much you will save in the long run over AP Motors, as well as the hastle of an ATF Permit. There are many cost benifit worksheets out there on the internet, just check them out.

We have tried to take into consideration what comments we have heard over the years from hybrid and AP flyers alike to make a product that is easy to use, and has high performance. We think the Rocket Community will be very happy!
Tom Sanders
Contrail Rockets LLC

 

[edwardw]

So, with your motors do you have to use your ignition sequence and thus buy your GSE?

Edward

 

[fyrechaser]

Tom, thanks for posting! I'm looking forward to more info as you guys get cranked up....I'll be watching your website.

 

[Ray Dunakin]

Originally posted by edwardw
So, just wanting a thought on why people don't fly hybrids and what they would like to see that would make them more attractive.

For me it's several things. The number one issue is the GSE. Not only the cost, which is substantial, but also the bulk and complexity. Nitrous tanks are heavy and take up a good deal of space, and I'm already filling my Trooper almost to the ceiling as it is.

The majority of my flying is done solo, so I can't depend on club equipment even if we had it.

I don't fly a lot of rockets in one place at one time, so I need something that fast and easy to set up and use.

The Aerotech hybrids were nearly ideal for my kind of rocketry, as they could be loaded at home. Main drawbacks are that the motor hardware was quite expensive and the loads were extremely limited in variety.

 

[ContrailRockets]

Originally posted by edwardw
So, with your motors do you have to use your ignition sequence and thus buy your GSE?

Edward

You can easily convert an existing GSE System that works for any of the other hybrid motors (Hypertek GSE is a bit different but can still be done easily). It will require a simple press lock T-Fitting. This will split the 1 fill line used in Skyripper, Ratt Works and Similar motors to 2 fill lines. If you’re at a sanctioned launch and have a high current source to hook the ignition leads to, you’re set. The other GSE Systems have everything but the splitter for the nylon fill lines.

Our Ignition sequence is very similar to an AP Motor. You fill like a Hybrid, but the Gox is not used. It’s just the flip of a switch, and off it goes. Our GSE has some bells and whistles to it, SS Line, Pratt Hobbies BFV Solenoid, and Standard Solenoid, High Current Relays, and a system which can also be used for AP Motors. If customers have Doug Pratt's System, it will work for our motors with a simple T-Connector as well.

Our "Igniters" are guaranteed to light our motors the first time using our GSE. If it is assembled properly, and wires hooked up the motors do not fail to light. We have not had a single ignition failure using our GSE and Standard Igniters.

You do not Have to Buy our GSE if you currently have another GSE System. They all have the same basic parts. Battery, Relays, Solenoids, Nos Bottle etc. Setting up the GSE to accept our motors should take under an hour, and possibly as quick as 5 Minutes if you have certain GSE Systems.

It is really much simpler than you probably are imagining. The Easier it is to use, the more customers will appreciate it.
Tom Sanders

 

[Donaldsrockets]

Complexity more than anything. Plus the fact electronics, altimeter, timer etc. are required for ejection.

Another and probably the main reason hybrid motors don't interest me, our club does not have hybrid gear.

Yeah I know, it's easily obtainable but I think we've never considered it is because of lack of interest.

I think I'll stick with good ol' reliable (most of the time) solid fueled motors.

 

[Focal]

As has been already stated, the two biggest things are complexity and GSE. If the club I plan to fly with had GSE, then I might consider it. The hybrid technology can be a little complicated to set up, and it does require more electronics, but they are electronics that I would probably have anyway by that point. Hard to say. But if MDRA got some hybrid GSE, then I would definitely conisder it.

 

[Austin]

I myself have not delved into Hybrids yet due to the startup cost of the GSE, support equipment and motor assemblies. With a GSE for Hypertek that can be used on all others btw, your talking near $600, plus the cost of additional fill stems(for smaller J/K motors), another $100+, two tanks, one for Oxy and one NOX at $500+ and an M Motor startup package at $500. Startup for other systems is a bit cheaper as the Oxy tank is elliminated, but all in all, you are looking at $1800-2000 for initial startup with everything you need...that is a substantial investment!

Then we have another promising vendor step in with inovative ideas on what Hybrid motors can really become. Tom, I would like to see more information regarding startup equipment, ignition materials and starting sequence, and details on what each one of your systems and packages contain on your website. An IPB of the internals would also be nice. Everything is a bit vague as listed and at $1800 for a 75mm startup motor system package, we want to know what we are getting.

These costs all in all are very prohibitive, if not impossible for most individuals. While the smaller hybrids may be gaining popularity as startup cost is much less, those that wish to fly J motors and above are looking at a major investment. I am also sure there are many clubs that could not afford such a cost, especially for the payoff they may get.

Still, I personally plan on investing in a GSE and startup equipment over the next year or so. I was fortunate enough to fly A Hypertek K240 at the Third Annual TRF Whitakers Launch last month and have witnessed many launches over the years, to including several Hypertek Armagedeon "M" flights and am hooked. While the complexity may turn some away, it's what I enjoy, so my goal is to be set up with everything I need in the next year to 18 months. We will see how that goes, but M flights from $130-180 are very attractive and much less that the pounds and pounds of propellant I have purchased in the past and I can store them without problems. To me, THAT is worth it!

 

[Chilly]

I really want to go Hybrid, but the GSE expense gets me like everyone else. The complexity is attractive, and it's the only way I can afford to think about L3 some day - assuming I can go use Carl's GSE!

 

[lalligood]

I agree with most if not everything that has been mentioned so far. There is one other "compaint" (and I do mean that in the loosest sense) I have about hybrids:

I would love to use them in a high drag type design (saucer or spool) where electronic deployment is not needed if almost unnecessary...which makes prep simplified greatly. The problem with using a hybrid in a high drag design is that the motor casings tend to be rather long compared to an equivalent solid propellant motor. This increased length means that there is more of the motor exposed out the top of the rocket. A short, fat hybrid motor casing for this purpose would be pretty sweet

The new Sky Ripper Systems 29mm & 38mm G motors would currently be about the best I can hope for...

Just my $0.02.

 

[Johnnie]

I have flown hybrids on and off for 6 - 7 years in the forms of HyperTEK, RATT, and SRS, with the HyperTEK dominating most of those flights...who can beat the K240 for $30 (+ nitrous) a flight

I had trouble struggling with the what if our clubs GSE craps out, and I am stuck hi-n-dri with a load of hybrid motors I can't fly. Getting my own GSE would be quite a "wallet drainer". Over the years I battled hybrids against solids, and thought that solids were just too darn cool to pass up...but now I am back to hybrids, and here to stay. Legally they are much less of a hassle than solids, and require me to think more when I play. With new innovations coming along everyday, inventors like Contrail Rocketry, Sky Ripper Systems, RATT, Westcoast, and Propulsion Polymers will help hybrids climb to the top of the market one day..

I knew I would have to make a decision to go one way or the other, on what ever form of propulsion I chose, and I weighed the GSE, and decided I will deal with that when the time is right. The time has been right lately, and as it turned out my GSE came to $390 instead of $582...you have to shop for GSE just like any other, and from my looking, the choice seemed very wise.

My reccomendation would be to talk to all the motor makers and get all the info you could possibly want or need...Also, ask a hybrid flyer lots of questions about the product, cause like any other rocketeer, we likes to talk about our stuff

A thread could be started within this thread or along side this thread with hybrid fliers telling us why they like to fly hybrids...could be quite informative. so I thought I might plug my $.02 in the slot.

 

[edwardw]

One thing I would like to see is better peformance from hybrids. The RATTWORKS K240 uses 2.682 lbs nitrous with 1801 Ns total impulse. I've tested a hybrid that uses 2.5625 lbs nitrous and has a total impulse of 3810 Ns. A little over 2000 Ns more impulse. I'd like to see hybrids that are higher performance and get all they can out of the motor.

As for GSE - something you have to buy like electronics, you have to bite the bullet.

Edward

 

[ContrailRockets]

Originally posted by Donaldsrockets
Complexity more than anything. Plus the fact electronics, altimeter, timer etc. are required for ejection.

Another and probably the main reason hybrid motors don't interest me, our club does not have hybrid gear.

Yeah I know, it's easily obtainable but I think we've never considered it is because of lack of interest.

I think I'll stick with good ol' reliable (most of the time) solid fueled motors.

Tripoli Rules state, that any rocket with what i believe to be L-Impulse and Above (Someone correct me if I am wrong) requires electronics for ejection. I know that Electronics are required for Level 3 Rockets. So having to put electronics into a rocket is not really anything that you would not have to do already with larger motors. Smaller rockets for the G-K Motors may tend to be a pain. It’s another step in setup, but it must be done on hybrids, big or small.

The Complexity really is not to bad once you take the time to learn about them. Sit down with a vendor, or manufacture at a launch (assuming you have a hybrid vendor or manufacture there) and have them give you a quick overview. I know we would all be more than happy to talk about our products! We have tried to simplify our motors as much as possible for the customer. Setup/Building of a Motor requires the Injectors (5 of them) to be threaded into the injector baffle with a 7/16 Socket. (Time 5 Minutes). Then the "Loom" of nylon lines gets plugged into the injectors (2 Minutes), Slide the Combustion Chamber on and bolt it together (2 Minutes), Grease and insert Fuel Grain (3 Minutes), Insert Nozzle and Bolt Together (3 minutes). Total time to build, 15 Minutes (not to bad for an M Motor.)
Give yourself a few extra minutes when first learning how to put them together, but it is really that simple!

At the Pad instead of taking the time to insert your igniter you just insert the nylon fill lines into the appropriate Press Lock Fitting and hook up the ignition leads. Takes just a minute or 2.

Filling is FAST! During TMT Testing we were filling motors in 30 seconds or less, Not the 2-3 Minute fills some other motors require.

GSE will continue to become more and more available over the next year. With great GSE Systems out there like Doug Pratt's, and our system which will soon be available using Doug's Solenoids, they will start popping up all over! With the ATF bearing down on AP motors, hybrids are looking like a great alternative. (not to mention the price is right).

And for Reliability, I have seen more igniter failures in 10 Minutes of Flying AP Motors at some launches than I have seen in the past 3 months of Motor Testing we have done. And We have not had a motor fail to light in Months now. Using our current system of ignition we have had 0 (ZERO!) Ignition Failures. I don't know of any other motors that can claim that!

Tom Sanders

 

[tquigg]

What keeps me from flying hybrids is the cost of the ground support equipment, coupled with the lack of local sources for NOS. I'd probably give it a try, were it not for these two factors.

 

[Dev Gnoll]

Since I fly solo and impromtu a lot, Hybrids are just too powerfull.

Given the amount of planning I do, anything requiring FAA notice is just going to sit.

 

[ContrailRockets]

Originally posted by CTulanko
I myself have not delved into Hybrids yet due to the startup cost of the GSE, support equipment and motor assemblies. With a GSE for Hypertek that can be used on all others btw, your talking near $600, plus the cost of additional fill stems(for smaller J/K motors), another $100+, two tanks, one for Oxy and one NOX at $500+ and an M Motor startup package at $500. Startup for other systems is a bit cheaper as the Oxy tank is elliminated, but all in all, you are looking at $1800-2000 for initial startup with everything you need...that is a substantial investment!

Then we have another promising vendor step in with inovative ideas on what Hybrid motors can really become. Tom, I would like to see more information regarding startup equipment, ignition materials and starting sequence, and details on what each one of your systems and packages contain on your website. An IPB of the internals would also be nice. Everything is a bit vague as listed and at $1800 for a 75mm startup motor system package, we want to know what we are getting.

These costs all in all are very prohibitive, if not impossible for most individuals. While the smaller hybrids may be gaining popularity as startup cost is much less, those that wish to fly J motors and above are looking at a major investment. I am also sure there are many clubs that could not afford such a cost, especially for the payoff they may get.

Still, I personally plan on investing in a GSE and startup equipment over the next year or so. I was fortunate enough to fly A Hypertek K240 at the Third Annual TRF Whitakers Launch last month and have witnessed many launches over the years, to including several Hypertek Armagedeon "M" flights and am hooked. While the complexity may turn some away, it's what I enjoy, so my goal is to be set up with everything I need in the next year to 18 months. We will see how that goes, but M flights from $130-180 are very attractive and much less that the pounds and pounds of propellant I have purchased in the past and I can store them without problems. To me, THAT is worth it!

When considering cost of flying you need to consider a few things. Hardware, GSE, and Reloads. Hardware for a Dr. Rocket 6400 N/s Motor is 400 Bucks. or the 5120 is 340.00. Our Hardware is 550.00 for a complete motor. About 200 Dollars more than the Aerotech System. GSE is going to run you anywhere from 300-750 Depending on what all you want and what features you are willing to pay for. Reloads for an M motor are going to run you 300 Bucks for AP, or 165-180 for Our Hybrids.

After a few flights it cheaper to fly Hybrids. Not to mention no BATFE.

I am working to get more information posted to the website daily, possibly some graphical descriptions of what each system contains, and what each Reload contains. After seeing it with pictures it’s much easier to understand. What is an IPB though? I am not familiar with the Acronym, or if I am, I am drawing a blank for some reason. The Most complete system available for all certified motors at this time is the 75mm-3200cc-System which is priced at 825.00 MSRP. This includes the 3200cc Nitrous Tank, 2 Combustion Chambers (one for 11.875 Inch Grains, and another for 17.875 Inch Grains), and 3 Nozzles (Slow, Mid, and Fast) for each reload speed.

Tom Sanders

 

[ContrailRockets]

Originally posted by lalligood
I agree with most if not everything that has been mentioned so far. There is one other "compaint" (and I do mean that in the loosest sense) I have about hybrids:

I would love to use them in a high drag type design (saucer or spool) where electronic deployment is not needed if almost unnecessary...which makes prep simplified greatly. The problem with using a hybrid in a high drag design is that the motor casings tend to be rather long compared to an equivalent solid propellant motor. This increased length means that there is more of the motor exposed out the top of the rocket. A short, fat hybrid motor casing for this purpose would be pretty sweet

The new Sky Ripper Systems 29mm & 38mm G motors would currently be about the best I can hope for...

Just my $0.02.

How about a short stubby 152mm Hybrid? Maybe something like an L (Possibly to short), or an M (More realistic for something like this). With something this powerful, a 2-2.5 foot motor isn't bad at all. Thats a big Spool Though

Tom Sanders

 

[lalligood]

Originally posted by ContrailRockets
How about a short stubby 152mm Hybrid? Maybe something like an L (Possibly to short), or an M (More realistic for something like this). With something this powerful, a 2-2.5 foot motor isn't bad at all. Thats a big Spool Though

Tom Sanders

Yeah! Now yer talkin' IMHO, that's a great L/D ratio for a motor... Something comparable proportion-wise but with a smaller diameter (like 75mm) would really be something (not to mention more economically reasonable)!

I watched my first large hybrid launch a couple of months ago. I believe it was the K240. Loud. I mean REALLY LOUD compared to an equivalent solid motor. It was the kind of launch that demonstrates how cool hybrids can be...

 

[Austin]

Originally posted by ContrailRockets
When considering cost of flying you need to consider a few things. Hardware, GSE, and Reloads.
Tom Sanders

Don't forget about the NOX and possible O2 tanks...about another $500 or so...

Tom, your prices are right in line and I am glad to see that! I have no problem buying the initial hardware; as one who has bought some of the 75mm AMW RMS and several of the 7680ns on up 98mm AT RMS, spending the money for a startup hybrid system is worth it. Like I said, the GSE and Tanks are what deter many. What is getting me started is the fact that there is one launch I do attend that has a Hypertek GSE, making the cost much cheaper. That is why I would like to see more details on your products.

As far as show and tell, I think it is a great thing to do and should be encouraged by all Hybrid Vendors as much as possible. The System, while complex, is really pretty simple in theory, even for Hyperteks and may pick up speed if the public knew more of what it actually takes. I learned a ton from Scott Miller and highly recommend him and SFSM Industries for hybrid purchases. This guy knows his stuff and carries a very heavy duty GSE with a killer NOX solonoid, capable of taking even the most extreme abuse. I am looking forward to shopping, Especially with some of the new motors available and hope it only gets better.

 

[brianc]

Originally posted by ContrailRockets
Filling is FAST! During TMT Testing we were filling motors in 30 seconds or less, Not the 2-3 Minute fills some other motors require.

Of the few (<10) hybrid launches I've seen down here in Florida, I can remember about half of those
having trouble with the fill process. It's hard to maintain the temperature differential between the
tanks in the hot Florida summer...

Does your system address or improve on this (besides the option to pre-fill)?

 

[ContrailRockets]

Originally posted by brianc
Of the few (<10) hybrid launches I've seen down here in Florida, I can remember about half of those
having trouble with the fill process. It's hard to maintain the temperature differential between the
tanks in the hot Florida summer...

Does your system address or improve on this (besides the option to pre-fill)?

You have to take into consideration where you are at. We are based out of Lake Havasu City, AZ. People either know Lake Havasu Because it has the london bridge, Spring Break, or Its the Hottest Place On Earth (At least it feels like it during the summer). We are constantly watching the temperature of our tanks. We own 4 K Cylinders, and often have at least one more as a rental. We just swap them out with our supplier, and the tanks are almost always black. (we have gotten a grey one before). Anyone who sticks a big black tank of Nitrous Oxide in the Arizona Sun (or Florida Sun) should be expecting to have to cool it off. An Old Towel, Bedsheet or Simmilar will work nicely on Warm Days. On Hot Days (Havasu is known to get above 120 in the summer), You will probably want to stick the bottle in a bucket of ice. We have a bunch of 10 Gallon Buckets which we fill with ice water for the bottem half and cover the top half with a wet towel.

I saw somewhere that they recommended putting a fishtank thermometer on the tank to measure the temperature and i though that was a great idea.

Our motors can not be pre-filled at this time. And I highly doubt we will be doing anything with a pre-fill type design.

I have seen some hybrids have fill problems as well, but during the 16 Static Fires we did during TMT Testing just over a week ago, we had 1 fill error, and it was my fault for putting it together at 3 in the Morning and being tired. I am not exactly sure what filling malfunctions your refering to, but i have heard the Hypertek stems fall out, which is eliminated in our motors. Is there any others which are causing problems and i don't know about?

Tom Sanders

 

[bobkrech]

I think the three main reasons that hybrids are slow to catch on are:

1. higher GSE/startup costs;
2. low average thrust; and
3. some misunderstanding about the properties of nitrous.

I don't think there's anything inherently dangerous about the GSE/tank pressures. There's no more or less pressure inside it than is found in a CO2 fire extinguisher, and most people don't consider a CO2 fire extinuisher dangerous. In the hybrid GSE, there is 1 or 2 solenoid valves that must be sequenced before you push the launch button, but it's really not that complicated.

Hybrid ignition is more complex than the simple igniter up the nozzle used in a solid, and this is an area were improvements can made. In my opinion, a small reloadable motor type ignitor cartridge/casing through which the fill nitrous tube passes using a standard reloadable type ignition grain would make ignition just as easy and reliable as a solid.

You need electronics to deploy the recovery system, but there's lots of good electronic options available at reasonable cost. All ejection systems on the market today are pyro-based, even the Rouse-Tech CD-3 which requires and e-match and BP in the pyrovalve, so I'm not sure why that's any issue about pyrotechnic initiated ejection. The use of an airtight ejection canister filled with BP (which is how the CD-3 burns it's BP) is simpler, lighter and works at any altitude, so why add the additional weight, expense, and complexity of a gas cartridge powered ejection system.

The nitrous filling problems experienced in hot weather can be eliminated by shading the tank, and covering it with a white, quilt-like covering and by pouring water on the fabric to develop evaporative cooling. Done properly, the tank can be cooled to the dew point of the air which in the US rarely exceeds 85 F, and insure the delivery of liquid nitrous at a proper density and pressure. Alternatitively, a battery powered thermoelectric device could be manufactured to cool (or heat in winter) and insulated nitrous tank. These are two products that someone could develop and market.

There's a good choice of hybrids available, and Contrails has demonstrated that the average thrust can approach that of solids. I personally think that black wax will become the preferred fuel. It is easy to cast, and if properly combusted, will give the same specific impulse as a liquid kerosine/nitrous motor. Enhanced inner core surface areas can be used to increase the average thrust as well.

Lastly, what makes any rocket motor a high power motor is not the fuel employed but rather a total impulse rating greater than 160 N-S. That's defined by NFPA, CPSC, and other regulatory agencies. Since hybrids are reloadable, they can only be flown by adults, which is a good thing, since by the time you are 18, it is assumed you can read, understand and follow the manufacturers directions which should insure a succesful flight.

Bob Krech

 

[ContrailRockets]

Originally posted by bobkrech
I think the three main reasons that hybrids are slow to catch on are:

1. higher GSE/startup costs;
2. low average thrust; and
3. some misunderstanding about the properties of nitrous.

I don't think there's anything inherently dangerous about the GSE/tank pressures. There's no more or less pressure inside it than is found in a CO2 fire extinguisher, and most people don't consider a CO2 fire extinuisher dangerous. In the hybrid GSE, there is 1 or 2 solenoid valves that must be sequenced before you push the launch button, but it's really not that complicated.

Hybrid ignition is more complex than the simple igniter up the nozzle used in a solid, and this is an area were improvements can made. In my opinion, a small reloadable motor type ignitor cartridge/casing through which the fill nitrous tube passes using a standard reloadable type ignition grain would make ignition just as easy and reliable as a solid.

You need electronics to deploy the recovery system, but there's lots of good electronic options available at reasonable cost. All ejection systems on the market today are pyro-based, even the Rouse-Tech CD-3 which requires and e-match and BP in the pyrovalve, so I'm not sure why that's any issue about pyrotechnic initiated ejection. The use of an airtight ejection canister filled with BP (which is how the CD-3 burns it's BP) is simpler, lighter and works at any altitude, so why add the additional weight, expense, and complexity of a gas cartridge powered ejection system.

The nitrous filling problems experienced in hot weather can be eliminated by shading the tank, and covering it with a white, quilt-like covering and by pouring water on the fabric to develop evaporative cooling. Done properly, the tank can be cooled to the dew point of the air which in the US rarely exceeds 85 F, and insure the delivery of liquid nitrous at a proper density and pressure. Alternatitively, a battery powered thermoelectric device could be manufactured to cool (or heat in winter) and insulated nitrous tank. These are two products that someone could develop and market.

There's a good choice of hybrids available, and Contrails has demonstrated that the average thrust can approach that of solids. I personally think that black wax will become the preferred fuel. It is easy to cast, and if properly combusted, will give the same specific impulse as a liquid kerosine/nitrous motor. Enhanced inner core surface areas can be used to increase the average thrust as well.

Lastly, what makes any rocket motor a high power motor is not the fuel employed but rather a total impulse rating greater than 160 N-S. That's defined by NFPA, CPSC, and other regulatory agencies. Since hybrids are reloadable, they can only be flown by adults, which is a good thing, since by the time you are 18, it is assumed you can read, understand and follow the manufacturers directions which should insure a succesful flight.

Bob Krech

Hybrids, by myself at lest are less dangerous than AP any day! Once AP Burns it can not be put out. (for the most part). I would have no problem keeping Hybrid Grains next to my bed, or the igniters for that matter. (Actually i have about 2 dozen of our igniters i was putting together at home the other day). It doesn't phase me a bit! Has anyone ever really considered why AP is somewhat regulated? I still consider it safe, as do many, but i don't consider it safer than hybrids.

Quote : Hybrid ignition is more complex than the simple igniter up the nozzle used in a solid, and this is an area were improvements can made. In my opinion, a small reloadable motor type ignitor cartridge/casing through which the fill nitrous tube passes using a standard reloadable type ignition grain would make ignition just as easy and reliable as a solid. End Quote.

That is close to what we have done. To hook up the motor for ignition you just hook up 2 pairs of wires. (4 wires total). We have dual igniters in our motor to ensure positive and fast ignition. There is no AP Preheater, no GOX/LOX, no Steel Wool, no Speaker Wire... All gone! And you get to put the igniter in before you get to the pad!

Quote:There's a good choice of hybrids available, and Contrails has demonstrated that the average thrust can approach that of solids. I personally think that black wax will become the preferred fuel. It is easy to cast, and if properly combusted, will give the same specific impulse as a liquid kerosine/nitrous motor. Enhanced inner core surface areas can be used to increase the average thrust as well.

Prior to us certifying our motors last week, The Fastest L Motor was an L-1500 by Aerotech. Now today we get to fly a "Worlds Highest Average Impulse Certified Hybrid". An L-2525 to be exact! Over 60% Faster than the old fastest L Motor. Its Fast! Over 1000 Pounds of Peak Thrust. Thats more than any other motor other than the Aerotech N-4800 and Pro 150 O-5100!
If I am not mistaken both of those are for Commercial use, and are not exactly easy to get. The L-2525 is a great motor for testing out your Level 3 Rocket with a Level 2 Motor before all the pressure of that Level 3 Flight.

I am working to get some final numbers for everyone regarding GSE. We have the GSE finished, it just needs a price. We are looking to have an "Economy System" as well as a "Premium System" for those who want to have the bells and whistles. Hopefully that will help dispell the myth that GSE is Soooo Expensive.

Tom Sanders
Contrail Rockets LLC

 

[JDcluster]

At first I thought they were alright & actually bought a HT 835 motor set, then I saw the nightmare of setting them up & seeing allot of them fail due to the GSE problems. Our club has a GSE setup , but hasn't been used in at least 3 years.
The preformance doesn't justify the extra time for setup & to fill the NOS tanks and all.
If you were to add the flight hardware to the propellant weight , then you'd see how bad the preformance on hybrids really is

All that work for really wimpy motors



JD

 

[Todd Moore]

Originally posted by JDcluster


All that work for really wimpy motors


JD

They aren't for everyone.

An aerotech J90 is a 'real wimpy motor', but it is also cool as hell.

Hybrid flyers understand why they are 'worth it'. You don't? Oh well.

We'll sleep OK tonight anyway.