Hybrids 2021

[kramer714]

Tuesday morning got the 20lb nox bottle hydrotested. No problem with my local place on mission in Pomona. Went to air gas to get the bottle filled with food grade nox. $65 / 20lbs but they wanted to do an inspection of my facility. Had the salesman out yesterday and showed him gse and rockets. He signed off but it is a 5 day turn around to get my tank back since they fill at main plant in LA. They would sell me a full tank for $220 but no dip tube. Local speed shops will fill but want over $100 for the 20lb tank and it is sulfurated. What are other folks doing?

I fill at a local speed shop in Orange County $5.00 per lb, while you wait. I have a 50lb, 20lb, and a 10lb tank. I fly at Lucerne.

 

[Dan Griffing]

Just for fun read the AeroTech pre filled Hybrid manual. The Safety section recommends leather gloves filling and purging tank to get cold enough for filling to occur the critical need not to over fill. Weight is critical. Also noted is the potential of accidental ignition if the Pyro seal breaks or if contaminated Grease is introduced. Motors once at 75 degrees are to be assembled at the pad, ensure that you are not in the nozzle flame path or that the rupture valve is pointing away from you while wearing your leather gloves. Install assembled motor into rocket then when vertical and only then install the electric match which has masking tape in a small cup filled with black powder and pinched at the top. Using the supplied guide insert into motor until one inch of guide is exposed instal motor cap which has been cut to the nozzle and tape in place.
In the event the motor fails to fire they recommend that you get your leather gloves and remove and disassemble the motor starting the process over.
Pad filled motors using remote fill do not require fill and purge as they purge thru the vent which in many cases is thru the combustion chamber. More importantly you are never near a motor that could release pressureized NOS or worse ignite during assembly or disassemble.
The remote pad fill system is faster and safer as I can prebuilt motors before a launch. Have them loaded and secured in a rocket install on rail hook up fill and fire connection with no risk.
In a 440 cc hybrid motor I can fill it during the five second count down. Facts not just my opinion.

Most importantly, a hybrid motor that’s been prefilled with NOS is much more dangerous than an inert one whose NOS tank is only filled seconds before being launched.

And NOS prefilled motors are much more complex and expensive to build. The complexity and expensive of Contrail-like hybrids resides in the onetime purchase of the ground support equipment. Aside from the GSE, the Contrail motors, especially with the new bottom venting and CVNA injectors are really simple.

And the industrial-grade “denatured” NOS is used by racing motor sports including snow machines here in Montana. Its sold at welding supply outlets. This is different from the highly regulated medical-grade nitrous oxide used by dentists that could be abused as “laughing gas”.

 

[crossfire]

That's great news.

 

[crossfire]

Most importantly, a hybrid motor that’s been prefilled with NOS is much more dangerous than an inert one whose NOS tank is only filled seconds before being launched.

And NOS prefilled motors are much more complex and expensive to build. The complexity and expensive of Contrail-like hybrids resides in the onetime purchase of the ground support equipment. Aside from the GSE, the Contrail motors, especially with the new bottom venting and CVNA injectors are really simple.

And the industrial-grade “denatured” NOS is used by racing motor sports including snow machines here in Montana. Its sold at welding supply outlets. This is different from the highly regulated medical-grade nitrous oxide used by dentists that could be abused as “laughing gas”.

I never thought Alpha Hybrids were all that complex.

 

[kramer714]

Once you get the 'hang of things' hybrids like the Contrail are pretty easy to launch. The advantages to the prefilled have more to do with the GSE, but per the comments, the 'prefilled' are filled on site, not at home.

Anyone from So Cal that is interested in Hybrids, happy to show you how or have you use my GSE at one of the ROC launches.

 

[Bruce]

Is there anyone in Washington or Oregon flying hybrids?

 

[jderimig]

Presently ContrailRockets.net is under development once done all contrail Rocket.com data will be on the new site along with new items being added. Reloads have yet to be moved. Contrail Rocket. Com has not had a price increase since 2008. The new . Net site fixes that as well as adding shipping charge.
I am pleased at the progress in the last months compared to the two previous website designers years of delays in development.

You mean no price increases has been fixed? :-(

 

[ContrailRockets]

You mean no price increases has been fixed? :-(

2008 prices will be going away with the launch of the updated website and conversion of the old ContrailRockets.com Front Page website to Word Press.
Contrail Rockets was free shipping in lower 48 that to is going away.
Due to increased shipping costs by all carriers Contrail Rockets can not continue to offer that free service. One benifit to my international customers is that you will be able to order directly from the website without needing to contact me about invoicing and shipping charges. I continue to fill orders using the 2008 prices on the .com site and my website developers told me the conversion should be done in about a month.

 

[crossfire]

2008 prices will be going away with the launch of the updated website and conversion of the old ContrailRockets.com Front Page website to Word Press.
Contrail Rockets was free shipping in lower 48 that to is going away.
Due to increased shipping costs by all carriers Contrail Rockets can not continue to offer that free service. One benifit to my international customers is that you will be able to order directly from the website without needing to contact me about invoicing and shipping charges. I continue to fill orders using the 2008 prices on the .com site and my website developers told me the conversion should be done in about a month.

Sounds like a good number of changes coming. Is the Trojan line of motors dead. Do you have a picture of one? I never did see one. Would Contrail ever consider a prefilled motor?
Thanks

 

[ContrailRockets]

Sounds like a good number of changes coming. Is the Trojan line of motors dead. Do you have a picture of one? I never did see one. Would Contrail ever consider a prefilled motor?
Thanks

Kramer714 flys the Trojan 330 cc 54 mm H-200. With the advances being made in injector and grain design I do not see that happening. I have bins of 54, 75, 98 hardware collecting dust that for someone who wants to EX and has Hypertek tanks I would be open to selling cheap.
I eliminated the Hypertek NOS tank and the Trojan adapter and created a hybrid motor using only the Trojan motor combustion chamber.
The short 54 mm 11.25 long Trojan combustion chamber has 250 cc of NOS and by using a 2.5 inch long pleated grain, CNVA, internal vent system and a 4.8 gram “Ring of Fire” preheater
Created a short L1 motor without the need to drill holes in your rocket for a vent
View attachment IMG_6027.MOV

 

[dhbarr]

Kramer714 flys the Trojan 330 cc 54 mm H-200. With the advances being made in injector and grain design I do not see that happening. I have bins of 54, 75, 98 hardware collecting dust that for someone who wants to EX and has Hypertek tanks I would be open to selling cheap.
I eliminated the Hypertek NOS tank and the Trojan adapter and created a hybrid motor using only the Trojan motor combustion chamber.
The short 54 mm 11.25 long Trojan combustion chamber has 250 cc of NOS and by using a 2.5 inch long pleated grain, CNVA, internal vent system and a 4.8 gram “Ring of Fire” preheater
Created a short L1 motor without the need to drill holes in your rocket for a vent
View attachment 459489

I have the Hypertek 54's, would love to buy a complete set of Trojan 54's.

 

[ContrailRockets]

I have the Hypertek 54's, would love to buy a complete set of Trojan 54's.

Tank not included
Won’t charge extra for the dust
Have about a dozen in bin
H-200 set up you supply Hypertek tank single reload included $100

 

[Dave A]

I fill at a local speed shop in Orange County $5.00 per lb, while you wait. I have a 50lb, 20lb, and a 10lb tank. I fly at Lucerne.

I did the same at Budds Creek, MD dragway. $5/lb. filling my 20# cylinder. I used to race there but was crewing for friend. I showed the vendor a picture of my 13' IRIS launching on a Contrail M, he got a big kick out of that.

 

[ContrailRockets]

Contrail Fast Fill NOS Solenoid Valve

Contrail Rockets is proud to announce that is the exclusive dealer for the new "Contrail Fast Fill" solenoid valve. This monster 12 volt solenoid valve has 1/2 NPT. This NOS valve is designed for continuous duty. The existing NOS valves from Pratt Hobbies have a manufacture recommended on time of only 5 minutes. The Contrail Fast Fill valve uses only 11 watts of power less than 1/3 of the power consumption of the BFV.

This valve has a massive 375 orifice with an area of .1104 that is almost 10 times larger than a BFV.

You want faster fills?

You want a valve to fill monster hybrid motors?

 

[crossfire]

How far up the motor size is the Pratt solenoid sufaciate?

 

[ContrailRockets]

How far up the motor size is the Pratt solenoid sufaciate?

Area of Orfice in CFF .1104 11 watts
Area of Orfice in BFV .0113 34 watts

 

[crossfire]

So should still have a rapid fill in J K reloads useing Pratts solenoid?

 

[ContrailRockets]

So should still have a rapid fill in J K reloads useing Pratts solenoid?

My internal vent 54 mm 630 cc fills with BFV in under 10 seconds. BFV has maximum on time by the manufacturer of five minutes so on large motors with longer fill times this becomes an issue.

 

[crossfire]

Thanks for info

 

[G_T]

I did the same at Budds Creek, MD dragway. $5/lb. filling my 20# cylinder. I used to race there but was crewing for friend. I showed the vendor a picture of my 13' IRIS launching on a Contrail M, he got a big kick out of that.

Hi Dave,

In Centreville VA here - can one get a larger tank filled? Can a stranger get one filled or only somebody they know? Will they do the cleaning for oxidizer service? I'll get a tank if I can get it filled and that price sounds quite nice.

Gerald

 

[kramer714]

Hi Dave,

In Centreville VA here - can one get a larger tank filled? Can a stranger get one filled or only somebody they know? Will they do the cleaning for oxidizer service? I'll get a tank if I can get it filled and that price sounds quite nice.

Gerald

My suggestion is to find a speed shop, tell them what you are doing. Most will sell you tanks, or will install a valve in a CO2 tank to convert it. My tanks were CO2 tanks that had the valves swapped out by the speed shop. Remember to make sure you have a siphon tube. You want to draw liquid not gas from the tank.

Be careful of used tanks that are out of hydro, you will need to add the cost of the hydro, cheep tank may not be so cheep after that. If you do buy a new CO2 tank, make sure that It was recently tested, not fun to buy a new tank and realize it was a few years old, not a performance problem just how long before hydro testing.

A brand new 20lb CO2 tank WITH A HANDLE should be less than $150 delivered. The handle, many of the tanks for cars don't have a handle, trust me, get one with a handle. It also protects the valve when transporting it.

One last thing, years ago I started adding a short (2 foot) hose to the end of my fill hose (the braided steel hose attached to the regulator, not the plastic hose coming from the motor). The end of the hose can get damaged from the exhaust from the motor or from being whipped. Cheep to replace the 2 foot piece, and to keep a spare in case it gets damaged during a day of flying. One last thing, buy a cap for the valve outlet for when you transport the tank.

 

[ContrailRockets]

Praxair in Arizona charges me $35 to Hydro test my 50 pound aluminum cylinders. Aluminum cylinder should be hydro tested every five years and steel every ten. Older full tanks do not need to be emptied if out of date just when you go in to have them refilled they will need to be re-certified.

 

[crossfire]

My suggestion is to find a speed shop, tell them what you are doing. Most will sell you tanks, or will install a valve in a CO2 tank to convert it. My tanks were CO2 tanks that had the valves swapped out by the speed shop. Remember to make sure you have a siphon tube. You want to draw liquid not gas from the tank.

Be careful of used tanks that are out of hydro, you will need to add the cost of the hydro, cheep tank may not be so cheep after that. If you do buy a new CO2 tank, make sure that It was recently tested, not fun to buy a new tank and realize it was a few years old, not a performance problem just how long before hydro testing.

A brand new 20lb CO2 tank WITH A HANDLE should be less than $150 delivered. The handle, many of the tanks for cars don't have a handle, trust me, get one with a handle. It also protects the valve when transporting it.

One last thing, years ago I started adding a short (2 foot) hose to the end of my fill hose (the braided steel hose attached to the regulator, not the plastic hose coming from the motor). The end of the hose can get damaged from the exhaust from the motor or from being whipped. Cheep to replace the 2 foot piece, and to keep a spare in case it gets damaged during a day of flying. One last thing, buy a cap for the valve outlet for when you transport the tank.

What is the hydro test?

 

[dhbarr]

What is the hydro test?

They fill it with water then crank up the pressure and look for leaks. Note that just running the pressure up with air is maybe-kaboomy.

 

[kramer714]

They fill it with water and run the pressure to above the gas working pressure, usually 1.5 times the gas operating pressure. The tank gets filled with water, then they pressurize the tank measuring the weight/volume of water that goes in under pressure and the amount of water that comes out after the test. There is evidence of the tank stretching (plastic deformation) if all the water added under pressure doesn't come back out, that means the tank permanently stretched during the test - failure. it is rejected.

They also check for leaks, check the threads for deformation, and 'peek inside' looking for corrosion. Needless to say, per dhbarr kaboomy is another reason for failure. Usually tanks fail for one of the other reasons not kaboomy.

The top of the tank gets metal stamped with the date of the hydro. I have one steel CO2 tank I use for welding, it is at least 40 years old, still use it, just passed a hydro a year ago. I think DOT limits tanks to 99 years.

Not talking about EX here - but I have advised a few college teams about how to SAFELY test their home made motor cases before flight. I still remember one team, the kid didnt want to test the motor case, the concern was if it failed the test they wouldn't have a case to launch......

 

[G_T]

I'd already been through all the speed shops within a fair radius, but that was a couple years ago now. Nobody was selling - usually not even getting to the question of what do you want it for. That's why I was asking.

Gerald

 

[ContrailRockets]

I'd already been through all the speed shops within a fair radius, but that was a couple years ago now. Nobody was selling - usually not even getting to the question of what do you want it for. That's why I was asking.

Gerald

In 2016 one of the major NOS manufacturer shut down This forced the diversion of all NOS to the medical users and extended well beyond original projections. Their production is back up helping to eliminating the shortage.

 

[kramer714]

I'd already been through all the speed shops within a fair radius, but that was a couple years ago now. Nobody was selling - usually not even getting to the question of what do you want it for. That's why I was asking.

Gerald

In 2016 there was an explosion at one of the nitrous oxide factories (Airgas I think) cut the supply way down. For a while after that the speed shops were not selling NOS to people they didn't know or didn't buy hardware from them. I had a relationship with my guy, he sold me what I needed. I think the supply shortages are gone now.

(I think Tom and I answered that one at the same time)

 

[jderimig]

Must have been a regional issue. I had no problems getting fills in 2017 and 2018 in Ohio.

 

[rocket_troy]

They also check for leaks, check the threads for deformation, and 'peek inside' looking for corrosion. Needless to say, per dhbarr kaboomy is another reason for failure. Usually tanks fail for one of the other reasons not kaboomy.

I think the point dhbarr was basically making was the primary reason why pressure vessels are hydrostatically tested (as opposed to pneumatically tested) is safety. Because liquids are practically incompressible (at the pressures we're dealing with) the only energy contained within a fully pressurized cylinder (filled with liquid) would be the elasticity of the cylinder itself as opposed to a pneumatically pressurized cylinder, so if there was a structural failure, the outcome is quite benign as opposed to something extremely & dangerously spectacular.

TP