Nitrous Oxide Tank Suppliers for G-rated motor

Hi,

I've been doing research and been having a little trouble looking for G-rated Nitrous Oxide tanks. I was hoping if anyone can point me in the right direction for buying a oxidizer tank for a G-class motor. We're trying to fit in a 2.25" tube or fuselage so within those specifications is what we need.

Thanks,
Nick Black

All hybrid motors are high power, and as this is a propulsion question it belongs in the propulsion forum.

Bob

https://www.catalinacylinders.com/

https://www.catalinacylinders.com/wp-content/uploads/2015/02/Nitrous-Spec.2-11-15color.pdf and the smallest tanks could be used to make a high G-impulse motors as they can contain 100 grams of N2O. CO2 and N2O tanks are identical. and have identical capacities by weight. As the motors are heavy a short burn, high thrust motor would be best.

A tanked G-hybrid motor would weigh >1 pound, and you won't find any commercial units. Certified Shyripper G-impulse hybrids were vented tank 29 mm and 38 mm monotube systems. None are in production today AFAIK, but Skyripper had several excellent ones, and Aerocon Systems and Pratt Hobbies may still have some in stock. https://aeroconsystems.com/motors/skyripper/skyripper_home.htm

Aerocon Systems sell RATT hybrids and a small E-impulse "Screamer" hybrid motor. https://aeroconsystems.com/cart/hybrid-motors/ https://aeroconsystems.com/cart/rockets-and-rocket-motors/screamer-16g-hybrid-rocket-motor/ The motor is not certified.

Pratt Hobbies is also a good source of hybrids. https://www.pratt-hobbies.com/products.asp?pg=3 https://www.pratt-hobbies.com/info_pages/infopages.htm
https://www.pratt-hobbies.com/contrail.htm

Contrails is still in business and do have 38 mm G-impulse hybrids. https://www.pratt-hobbies.com/contrail.htm https://www.pratt-hobbies.com/search.asp?nobox=&scat=&stext=contrail&stype=&sprice=&pg=2

Contrail Rockets makes larger hybrids as well. https://www.contrailrockets.com/ https://www.contrailrockets.com/Products/prod01.htm


Hypertek Hybrids makes larger hybrids. https://www.hypertekhybrids.com/

Bob

Hi Bob,

thanks for the reply and resources. We're actually going to be making our own motor though, with paraffin wax, carbon black, and aluminum powder as our fuel. I'm trying to find some information on what I can use for the oxidizer tank to be within the Competition limit of being G-rated or lower so we don't go over that limit and get disqualified possibly. But essentially, from what I gathered so far, the G-class will have to be verified through testing (for thrust curves and specific impulse) so I'm trying to get a good starting point to get a Nitrous Oxide tank to keep within the constraints for the testing (and for the future launch date). Will a stoichiometric analysis allow me to get a mass to use for the combination I'm using or would there be a better way to go about it?

Thanks,
Nick

nickb said:

Hi Bob,

thanks for the reply and resources. We're actually going to be making our own motor though, with paraffin wax, carbon black, and aluminum powder as our fuel. I'm trying to find some information on what I can use for the oxidizer tank to be within the Competition limit of being G-rated or lower so we don't go over that limit and get disqualified possibly. But essentially, from what I gathered so far, the G-class will have to be verified through testing (for thrust curves and specific impulse) so I'm trying to get a good starting point to get a Nitrous Oxide tank to keep within the constraints for the testing (and for the future launch date). Will a stoichiometric analysis allow me to get a mass to use for the combination I'm using or would there be a better way to go about it?

Thanks,
Nick

Click to expand...

Stoichiometric combustion =/= most efficient combustion in a rocket. It's also slightly complicated in hybrids since your liquid has to interact with a solid surface. Sutton's Rocket Propulsion Elements is a good place to start in general, Aerocon systems also has a book on hybrid motor design: https://aeroconsystems.com/cart/literature-and-software/hybrid-design-factors-by-bill-colburn/

A very good idea might be to buy an off the shelf G hybrid motor kit, and then just make your own fuel grain. You would reduce a lot of the risk of your system, and let you just focus on the motor design part. Then you don't have to worry about getting nitrous tanks and they will be sized close to what you would want. They would also be light enough to actually fly as well. Most off the shelf DOT tanks will be too heavy for you.

nickb said:

Hi Bob,

thanks for the reply and resources. We're actually going to be making our own motor though, with paraffin wax, carbon black, and aluminum powder as our fuel. I'm trying to find some information on what I can use for the oxidizer tank to be within the Competition limit of being G-rated or lower so we don't go over that limit and get disqualified possibly. But essentially, from what I gathered so far, the G-class will have to be verified through testing (for thrust curves and specific impulse) so I'm trying to get a good starting point to get a Nitrous Oxide tank to keep within the constraints for the testing (and for the future launch date). Will a stoichiometric analysis allow me to get a mass to use for the combination I'm using or would there be a better way to go about it?

Thanks,
Nick

Click to expand...

Xrain said:

Stoichiometric combustion =/= most efficient combustion in a rocket. It's also slightly complicated in hybrids since your liquid has to interact with a solid surface. Sutton's Rocket Propulsion Elements is a good place to start in general, Aerocon systems also has a book on hybrid motor design: https://aeroconsystems.com/cart/literature-and-software/hybrid-design-factors-by-bill-colburn/

A very good idea might be to buy an off the shelf G hybrid motor kit, and then just make your own fuel grain. You would reduce a lot of the risk of your system, and let you just focus on the motor design part. Then you don't have to worry about getting nitrous tanks and they will be sized close to what you would want. They would also be light enough to actually fly as well. Most off the shelf DOT tanks will be too heavy for you.

Click to expand...

+1 on the above advise. At this point, I feel you don't know what you don't know. I believe you really need to get up to speed on small hybrid motors before you attempt to build anything. Hybrids are actually more dangerous than solid rocket motors if you do not know what you are doing. Dealing with N2O is not as simple as you think, and filling a tank with liquid N2O requires attention to details or you will only fill it with gas and the motor will not work. If you mess up on your injector and nozzle sizing, you can blowup the nitrous tank due to motor instabilities and back flash detonation of the Nitrous in the oxidizer tank. (RE the Scaled Composites fatal Nitrous Oxide explosion.) For this reason, all hybrid motors are high power motors requiring a minimum separation distance of 100' with remote electronic filling and ignition.

IMO It is my professional opinion that you are wasting your time making a wax fuel G-hybrid. It's simply not large enough. And aluminum is not useful in such a small hybrid. You should be using a solid plastic tube as the fuel grain in a vented hybrid motor, not a tanked hybrid.

Contrails, Rattworks and Hypertek are the only surviving hybrid manufactures. Contrails, Rattworks and Hypertec make vented hybrids. Contrails and Rattworks used a vented monotube motor where as Hypertec uses a commercial tank and a custom fuel module. https://www.hypertekhybrids.com/products.html

https://www.contrailrockets.com/Products/prod01.htm


Are typical of what you can get using the Contrail 38 mm x 16" long vented hybrid casings.

https://www.contrailrockets.com/38store.htm store for 38 mm Contrail hardware



The casing size determines the N2O tankage and the motor rating. The 16" long casing is for G motors.

The operation of a hybrid is far more complicated and expensive than an APCP solid motor. You will need a remote nitrous filling systemin addition to a complex ignition system.

Please read up on all 3 manufactures before you decide what you need to do.

Bob

I think I would start with less than .20 pounds of nitrous oxide or 125 cubic centimeters. That is the size of the Skyripper G69. The G63 has a 75 CC tank. The Contrail has a 140 CC tank.

Okay, thank you for all the advice. I think we'll probably buy one to see what we are dealing with, too like you said. But when you buy one as a kit from these manufacturers does it come with the oxidizer as well or do we provide that on our own? Because I was looking at some such as Contrail Rockets for the 38 mm 16" motor as you mentioned above and from what I read it didn't seem like there was an oxidizer that came with it. I may be reading it wrong, though. Last year's team at my university actually used that kit from Contrail Rockets as well so I've been thinking on investing in that G-class motor from Contrail.

-Nick

Using any motor which has one of the components as a liquid or a gas requires GSE - Ground Support Equipment. The flight tank in an N2O based hybrid is under considerable pressure. It is not legal to transport the tank unless it is DOT rated for tranport filled. Some hybrids use separate tanks which are DOT rated and can be transported filled. Others, such as all the monotube hybrids, are filled at the pad, from a separate DOT rated tank outside the rocket which is part of the GSE.

In either case, you need a fill tank setup with valves, at a minimum. Research hybrid GSE and tanks.

Configurations for filling at the pad are more complex than ones used to fill a DOT rated tank that is then transported to the pad filled.

Please note that N2O is under sufficient pressure to be dangerous and even deadly if something goes wrong. It is also a monopropellant that is easily contaminated (it's a solvent) and becomes sensitized depending on the contaminant making it much more dangerous. IMHO you do not want to be messing with this without some basic knowledge of how it works and how it can go wrong. When you are not using commercial prepackaged equipment and motors you need to know a lot more to be safe.

Gerald

I have hybrid rocket specific GSE available for sale. I will be working on a website in the future that will list all these components. What you will need consists of: An electrical remote launch control system, a solenoid manifold, a nitrous oxide tank, and a launch pad/rail. I do not sell launch pad/rails. If interested contact me at [email protected]

nickb said:

I've been doing research and been having a little trouble looking for G-rated Nitrous Oxide tanks.

Click to expand...

OK, I don't know anything about it. Just one question though: why not a PG or PG-13 rated tank?

Hi, I have another question regarding the housing of the Nitrous Oxide. I plan on using GSE for filling the Nitrous Oxide into the rocket using a vented hybrid rocket motor configuration but I'm confused whether this vented type of hybrid configuration uses a tank to hold the Nitrous Oxide that sits inside the casing or if it just uses the space above the injector bulkhead in the aluminum casing that comes with Hybrid motor kits, such as Contrail Rocket kits for example. Otherwise I'm unsure of how a tank would be able to vent to the atmosphere during time of filling right before launch.

I know that DOT rated tanks can be used but I decided not to go that route because of safety.

To illustrate what I'm talking about look at this diagram from Rattworks. It shows in the motor casing that above the injector bulkhead and compression fitting is where the Nitrous Oxide is stored while in flight and it doesn't look like there are any tanks involved.
https://www.rattworks.net/29mm_hybrid_motors.html

If this is the case then it will reduce the costs of my project a lot by not needing to buy the tanks then.

Yes, monotubes like RATT and Contrail just use the space above the floating injector to store the N2O.

Are you familiar with the GSE required to remotely fill a vented rocket motor? I have GSE available for sale if you are in need to purchase it.

nickb said:

Hi, I have another question regarding the housing of the Nitrous Oxide. I plan on using GSE for filling the Nitrous Oxide into the rocket using a vented hybrid rocket motor configuration but I'm confused whether this vented type of hybrid configuration uses a tank to hold the Nitrous Oxide that sits inside the casing or if it just uses the space above the injector bulkhead in the aluminum casing that comes with Hybrid motor kits, such as Contrail Rocket kits for example. Otherwise I'm unsure of how a tank would be able to vent to the atmosphere during time of filling right before launch.

I know that DOT rated tanks can be used but I decided not to go that route because of safety.

To illustrate what I'm talking about look at this diagram from Rattworks. It shows in the motor casing that above the injector bulkhead and compression fitting is where the Nitrous Oxide is stored while in flight and it doesn't look like there are any tanks involved.
https://www.rattworks.net/29mm_hybrid_motors.html

If this is the case then it will reduce the costs of my project a lot by not needing to buy the tanks then.

Click to expand...

Look at the tutorial link you posted, there is an interactive link that describes step-by-step how the mono-tube hybrid is filled and fired. Being a mono-tube, the case has double duty of being the tank and combustion chamber, separated by a floating injector bulkhead.