Hybrids 2021

[DRAGON64]

A recent post on a facebook page run by Contrail Rockets LLC has highlighted a new 72" long by 98mm N15000 that has an improved injection system, and a 42-star fuel grain!!! (See the images posted below)

Had I not been following Contrail Rockets on facebook, I might not have found this info/images, and this new thread would not have resurrected the topic of hybrid rocketry... yet here we are!

Previous Threads:

Hybrids 2015
Hybrids 2016
Hybrids 2017
Hybrids 2018
Hybrids 2019
Hybrids 2020

Why another year in hybrids? Especially with interest nearly non-existent? Because 2021 marks the 12th anniversary of the NAR & TRA winning the lawsuit against the ATF, where-by removing APCP from the explosives list. This is the proverbial line in the sand, marking the time which we begin to see the decline of hobby based hybrids. Why you say? Because, of the 4 or 5 manufacturers that supplied our hobby, there is one left. One who still believes, and is trying to support us, and provide new hybrids for the small market. I am referring to Contrail Rockets.

It would seem that hybrids are thriving in the research world, rather than the commercial hobby industry. So, if you are indeed researching hybrids and or tri-brids, please post up the research in the proper research forum. But be sure to share your videos and flights here in the Hybrids forum. So, without further ado:

Another flying season gone-by, and a new one is just ramping up... what are your goals for flying hybrids during the 2021 flying season? Anything and everything hybrid related is welcome!

* Motors
* Vehicles
* Ground Support (GSE)
* Research motors discussion (within the limits of a non-research forum)
* Electronics
*Altimeters; Vent sensors; GPS etc etc
* Commercial/Professional advancement hybrid discussion
* College development (i.e. TUDelft etc etc)
* Events/Launch coverage
* New flyer questions

 

[mrwalsh85]

I picked up a small collection of gear from an estate clearinghouse, only to find that a box of Hypertek GSE was serialized for our club... St Louis Rocketry Association. D'oh! But further conversation revealed that this came from our former club president. We are investigating what is going on with him - hoping he has not passed, but maybe moved out and left it all to be cleared out. I am waiting on a conversation with our prefect who messaged me just now saying he made contact with a family member.

It seems we are missing the fill tube/bracket/plumbing assembly. Does anyone have prints/drawings for the Hypertek version? I'm not opposed to making one as I have a machine shop in the garage

Thanks
Mike

 

[Lowell]

I'd like to see specs on the Hypertek GSE, too. I have some of their stuff but not the on-the-pad fill tubes of the right size to be able to fill and fly them.

L.

 

[G_T]

I'm figuring on making an alteration to my injector assembly and adding a slight taper to the grain on THRP-1, when I get some time to do some machining. Still no nitrous though I do have the rest of my own GSE. I'd still like to fly it at Potter.

If people realized how much cheaper hybrids are than HTPB at current prices for medium sized L and M motors there might be more interest. Of course hybrids are more hassle. But they are fun particularly for EX. You don't have to mess with toxic chemicals with hybrids.

Gerald

 

[crossfire]

I really thought the prefilled tanks would make hybrids more popular.

 

[G_T]

Might have, if APCP regs hadn't changed. People recoiled back to APCP pretty quickly.

The plusses of prefilled are obvious. The minusses are extra wight so lower performance as a system, and the user needs his own N2O and (cheaper) GSE to show up with the motors ready to go. Monotube and similar pad-filled systems only require the club to have N2O and GSE. As a group, there is lower investment cost going the club and mostly fill at the pad systems.

Also most kits aren't hybrid ready anyway, and many more people build kits than scratch build.

Too bad using CO2 as an oxidizer is so picky of getting the O:F ratio exactly right, and even then performace would be bleah... All those Sodastream and paintball tanks...

Gerald

 

[Voyager1]

Our group used the TRA PIP grant to invest in some hybrid GSE a couple of years ago. When we want to fly hybrids we just pick up a DE bottle of N2O from the local supplier. A few of our members have a range of Rattworks and Contrail motors from 29mm to 75mm, although most remain on the dark side with their composite motors. Hybrids are much more interesting and once you have the GSE sorted, they are not much more of a bother to prep and fly. Additionally, it's very easy to modify an existing kit or built rocket to accommodate a hybrid motor. In most cases it just requires a simple booster extension.

We have our first HPR launch for 2021 next week. I'll be flying my Contrail 38mm/36" motor and, with luck, the maiden flight of my 54mm/28" Contrail motor.

 

[profmason]

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?

 

[ContrailRockets]

Contrail Rockets is improving the motors and reloads that we offer. COVID has done a number on the entire hobby and while folks were building Rockets for future launches they were not investing in motors.
During that period Contrail continued its R&D in improving the motors it offers. One of my customers ask if I could find a way to eliminate the need to drill holes in their minimum diameter 54 mm Carbon Fiber Rocket.
We are pleased to announce that 54 mm hybrid motors can now be vented through the combustion chamber. In addition we have several shorter 54 mm motors the 20 inch 600 cc where the old 28 inch was 530 cc. This has been accomplished using an improved injector baffle which incorporates the CNVA vortex, high surface area 4 inch long 13 star grains using the same fuel as the M 1491 Black Smoke. Ignition reliability has been increased using a cup igniter intergrated into the injector baffle. The internal vent runs thru the cup as well as a twin 12 volt resistor igniter set up. Aggressive redundancy in ignition in what Contrail Rockets is calling its “Ring of Fire”.
Work is underway to get not only the 20 inch motor certified by TMT but to also have all 54 mm motors certified with the internal vent. Under development and testing is a 54 mm 11.25 inch long 2.5 inch grain 250 cc hybrid motor using the features of the 20 inch motor.
Work on other motors including the 98 mm line of motors up to 72 inches long is continuing.

 

[Dan Griffing]

Contrail Rockets is improving the motors and reloads that we offer. COVID has done a number on the entire hobby and while folks were building Rockets for future launches they were not investing in motors.
During that period Contrail continued its R&D in improving the motors it offers. One of my customers ask if I could find a way to eliminate the need to drill holes in their minimum diameter 54 mm Carbon Fiber Rocket.
We are pleased to announce that 54 mm hybrid motors can now be vented through the combustion chamber. In addition we have several shorter 54 mm motors the 20 inch 600 cc where the old 28 inch was 530 cc. This has been accomplished using an improved injector baffle which incorporates the CNVA vortex, high surface area 4 inch long 13 star grains using the same fuel as the M 1491 Black Smoke. Ignition reliability has been increased using a cup igniter intergrated into the injector baffle. The internal vent runs thru the cup as well as a twin 12 volt resistor igniter set up. Aggressive redundancy in ignition in what Contrail Rockets is calling its “Ring of Fire”.
Work is underway to get not only the 20 inch motor certified by TMT but to also have all 54 mm motors certified with the internal vent. Under development and testing is a 54 mm 11.25 inch long 2.5 inch grain 250 cc hybrid motor using the features of the 20 inch motor.
Work on other motors including the 98 mm line of motors up to 72 inches long is continuing.

I’m getting ready to do a demonstration launch of this new Contrail Rockets 54mm x 20” hybrid motor in my new CF-modified Apogee Peregrine, hopefully at the next Big Sky Rocketry Association launch on April 17th.

 

[crossfire]

I think the prefilled tank type hybrids would have a chance to become popular. Most club launches are just not set up for hybrid flyers who need extra time to get rocket ready rocket for fireing.

 

[CoyoteNumber2]

What are other folks doing?

The last time I got a fill I had to drive ~90 minutes for it to a racing shop. Roughly $100 for 20 pounds. The local industrial gas supplier didn't even want to talk to me, like it was taboo to buy and sell nitrous or something.

 

[ContrailRockets]

The last time I got a fill I had to drive ~90 minutes for it to a racing shop. Roughly $100 for 20 pounds. The local industrial gas supplier didn't even want to talk to me, like it was taboo to buy and sell nitrous or something.

Praxair $195 for 56 pound K cylinder

 

[ContrailRockets]

I think the prefilled tank type hybrids would have a chance to become popular. Most club launches are just not set up for hybrid flyers who need extra time to get rocket ready rocket for fireing.

Pre Covid at TRAPHX At some launches I had the most launches of any flyer. While the AP flyers have to install igniters at the pad inert empty hybrid motors using a resistor igniter can be installed during motor assembly. Using a push to connect fill line and a set of gator clips on the twin igniter ignition leads, arm electronics and verify tracker on and Electronics armed.
Using the right GSE and solenoid valves allows a fast fill not delaying other flyers. In fact as they have Hybrid and AP in separate locations many times I wait for them and then launch last.
This process is faster then chilling and filling weight the tank and then waiting for tank to warm to flight temperature. A 54 mm 600 cc motor fills in about 10 seconds
The 3200 cc 75 mm M-1491 fills in under 60 seconds so in that minute I moved about $28 of NOS into a motor with a $95 reload. Contrail Rockets has tried to simplify hybrid motors eliminating the zip tied drop down fill stem the extra O2 tank and a high voltage spark to begin the ignition process. But with that in mind many of those old Hypertek systems easily work to fill and fire Contrail Rocket motors. Almost forgot purge as we hope with a Contrail Rocket motor you never have to do that.

 

[Dan Griffing]

Pre Covid at TRAPHX At some launches I had the most launches of any flyer. While the AP flyers have to install igniters at the pad inert empty hybrid motors using a resistor igniter can be installed during motor assembly. Using a push to connect fill line and a set of gator clips on the twin igniter ignition leads, arm electronics and verify tracker on and Electronics armed.
Using the right GSE and solenoid valves allows a fast fill not delaying other flyers. In fact as they have Hybrid and AP in separate locations many times I wait for them and then launch last.
This process is faster then chilling and filling weight the tank and then waiting for tank to warm to flight temperature. A 54 mm 600 cc motor fills in about 10 seconds
The 3200 cc 75 mm M-1491 fills in under 60 seconds so in that minute I moved about $28 of NOS into a motor with a $95 reload. Contrail Rockets has tried to simplify hybrid motors eliminating the zip tied drop down fill stem the extra O2 tank and a high voltage spark to begin the ignition process. But with that in mind many of those old Hypertek systems easily work to fill and fire Contrail Rocket motors. Almost forgot purge as we hope with a Contrail Rocket motor you never have to do that.

I did a GSE test on my 54mm 20” Contrail hybrid motor yesterday and confirm that it only takes only about 10 seconds to fill it with NOS before launch.

If purging is needed for some reason, it takes a lot longer, but under a minute to empty the hybrid motor’s NOS tank.

As far as I can tell, I’ll be able to get 8-10 launches with this one motor from one 18lb NOS supply tank fill.

 

[crossfire]

Pre Covid at TRAPHX At some launches I had the most launches of any flyer. While the AP flyers have to install igniters at the pad inert empty hybrid motors using a resistor igniter can be installed during motor assembly. Using a push to connect fill line and a set of gator clips on the twin igniter ignition leads, arm electronics and verify tracker on and Electronics armed.
Using the right GSE and solenoid valves allows a fast fill not delaying other flyers. In fact as they have Hybrid and AP in separate locations many times I wait for them and then launch last.
This process is faster then chilling and filling weight the tank and then waiting for tank to warm to flight temperature. A 54 mm 600 cc motor fills in about 10 seconds
The 3200 cc 75 mm M-1491 fills in under 60 seconds so in that minute I moved about $28 of NOS into a motor with a $95 reload. Contrail Rockets has tried to simplify hybrid motors eliminating the zip tied drop down fill stem the extra O2 tank and a high voltage spark to begin the ignition process. But with that in mind many of those old Hypertek systems easily work to fill and fire Contrail Rocket motors. Almost forgot purge as we hope with a Contrail Rocket motor you never have to do that.

I had a Alpha motor that I flew 3 times all went great. But when Alpha got out of selling motors I sold it. I just like to fly and am not into making home brew grains.

 

[CoyoteNumber2]

Praxair $195 for 56 pound K cylinder

The local industrial gas supplier didn't even want to talk to me, like it was taboo to buy and sell nitrous or something.

 

[crossfire]

Pre Covid at TRAPHX At some launches I had the most launches of any flyer. While the AP flyers have to install igniters at the pad inert empty hybrid motors using a resistor igniter can be installed during motor assembly. Using a push to connect fill line and a set of gator clips on the twin igniter ignition leads, arm electronics and verify tracker on and Electronics armed.
Using the right GSE and solenoid valves allows a fast fill not delaying other flyers. In fact as they have Hybrid and AP in separate locations many times I wait for them and then launch last.
This process is faster then chilling and filling weight the tank and then waiting for tank to warm to flight temperature. A 54 mm 600 cc motor fills in about 10 seconds
The 3200 cc 75 mm M-1491 fills in under 60 seconds so in that minute I moved about $28 of NOS into a motor with a $95 reload. Contrail Rockets has tried to simplify hybrid motors eliminating the zip tied drop down fill stem the extra O2 tank and a high voltage spark to begin the ignition process. But with that in mind many of those old Hypertek systems easily work to fill and fire Contrail Rocket motors. Almost forgot purge as we hope with a Contrail Rocket motor you never have to do that.

What I liked about prefilled I could just have the motor all ready at home.

 

[G_T]

Blame it on the people using N2O as a recreational drug. Hard to find a seller. I'd even switch to 90/10 Nitrox if I could get that instead, though it would require some redesign. EX hybrid person, ISO N2O or 90/10 nitrox.

Gerald

 

[ContrailRockets]

Blame it on the people using N2O as a recreational drug. Hard to find a seller. I'd even switch to 90/10 Nitrox if I could get that instead, though it would require some redesign. EX hybrid person, ISO N2O or 90/10 nitrox.

Gerald

Nitrox runs about $10 a pound and also at an elevated pressure of about 1800 psi. Not a TRA approved oxidizer plus the lower density does not warrant the added cost. The
existing NOS valves are designed for 750 psi max pressure 1125 psi. Existing nylon fill lines burst at 1500 psi and higher pressure lines require a longer hotter pre-heater. Existing NFPA codes require that hybrid motor tanks be designed to 3000 psi and tested to 2000 psi while only operating at 750 psi. With that same ratio for safety of four to one a cylinder designed to operate at 1800 psi would need to be designed to 7200 psi and tested to 4800 psi. Now lets go back to performance increase or more correctly performance decrease due to the increase motor weight.

 

[ContrailRockets]

Missed recreational use of NOS
To buy Medical grade NOS you need to be a Doctor.
We in the hybrid or racing community buy Nitrious Oxide with Sulfur Dioxide which makes you sick preventing recreational use.
Praxair or Airgas are both solid Nitrous Oxide suppliers. Speed shops up charge for trans filling. Buying larger quantities K cylinders has never been an issue. Sharing in a club reduces expense.

 

[CoyoteNumber2]

Every time I've had my tank filled, it was never with the sulfur-tainted stuff. The shop said it costs them more, so they only buy straight N2O.

 

[jderimig]

Many states have stepped up enforcement on using N2O on street cars and putting burdens on gas suppliers in the form of record keeping and paperwork. So I am not surprised that gas suppliers do not want small retail business. Blame the street racers not the drug users

 

[jderimig]

What I liked about prefilled I could just have the motor all ready at home.

Those are not DOT rated

 

[jderimig]

Pre Covid at TRAPHX At some launches I had the most launches of any flyer. While the AP flyers have to install igniters at the pad inert empty hybrid motors using a resistor igniter can be installed during motor assembly. Using a push to connect fill line and a set of gator clips on the twin igniter ignition leads, arm electronics and verify tracker on and Electronics armed.
Using the right GSE and solenoid valves allows a fast fill not delaying other flyers. In fact as they have Hybrid and AP in separate locations many times I wait for them and then launch last.
This process is faster then chilling and filling weight the tank and then waiting for tank to warm to flight temperature. A 54 mm 600 cc motor fills in about 10 seconds
The 3200 cc 75 mm M-1491 fills in under 60 seconds so in that minute I moved about $28 of NOS into a motor with a $95 reload. Contrail Rockets has tried to simplify hybrid motors eliminating the zip tied drop down fill stem the extra O2 tank and a high voltage spark to begin the ignition process. But with that in mind many of those old Hypertek systems easily work to fill and fire Contrail Rocket motors. Almost forgot purge as we hope with a Contrail Rocket motor you never have to do that.

I agree. Been flying Contrail for 10+ years now. I am the fastest on and off the pads.

 

[G_T]

Nitrox runs about $10 a pound and also at an elevated pressure of about 1800 psi. Not a TRA approved oxidizer plus the lower density does not warrant the added cost. The
existing NOS valves are designed for 750 psi max pressure 1125 psi. Existing nylon fill lines burst at 1500 psi and higher pressure lines require a longer hotter pre-heater. Existing NFPA codes require that hybrid motor tanks be designed to 3000 psi and tested to 2000 psi while only operating at 750 psi. With that same ratio for safety of four to one a cylinder designed to operate at 1800 psi would need to be designed to 7200 psi and tested to 4800 psi. Now lets go back to performance increase or more correctly performance decrease due to the increase motor weight.

No disagreement. However I run oxidizer at a controlled temperature below ambient. There are benefits for doing so with Nitrox just as there are with N2O. Just need somewhat lower temperatures for Nitrox vs N2O densification etc but the methods I'm already using can work for that, and the resulting pressure is lower. Nitrox has the benefit that, at least uncontaminated, it will not propagate a blast wave if things go seriously wrong. No, Nitrox is not approved; it probably has not even been considered for approval. Everything starts somewhere. Nitrox is a current research area for hybrid propulsion systems as there are certain potential safety and performance benefits.

FWIW, a hotter preheater is already required for chilled nitrous. I do not consider the higher Nitrox price to be prohibitive as it is still a fair bit cheaper than the APCP EX chems I've been using!

If the motor is of sufficient size then one can use separate supply of N2O and O2 and make a nitrox blend in the flight tank by bubbling O2 through the N2O and using boiloff for chilling and pressure control. Consistency would be an interesting challenge! Hardly worth the effort for anything under an N I expect. And it requires having N2O anyway, which right now I don't have.

In my area a few years back there was apparently some raid on a big party where they were using a large N2O tank for recreational purposes. Then the suppliers around here got visits... That's the story I got from one of the former suppliers. N2O became essentially impossible to get within quite a ways from here. I tried a whole bunch of places that used to supply. Most wouldn't even talk with me. Now, I don't know. It may be available again. But given the apparently rising problem of N2O being mis-used, I doubt it. Of course it's mostly whippit cylinders that are being misused and those are readily available. And as has been pointed out, street racing is also an issue. I think it has gone a bit more underground around here.

I do hope hybrids make a bit of a comeback at launches. They are something different. And if APCP becomes problematic again, or if the price keeps on rising, then we have a third good HPR alternative (APCP, Sugar, N2O hybrid).

I've got ideas towards a fourth cheap option, except I need a small high pressure high volume turbopump as the oxidizer won't be self pressurizing. Or I need a high pressure helium tank or reasonable substitute. Or I'll have to develop a good gas generator which might be the most practical on the small scale that we work at. So the fuel and oxidizer will be very cheap but the hardware, not so much so.

N2O has a lot going for it.

Gerald

 

[ContrailRockets]

What I liked about prefilled I could just have the motor all ready at home.

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.

 

[crossfire]

Those are not DOT rated

I don't have the motors any

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.

Dose Contrail have a newer up dated web site?

 

[G_T]

You got me curious so I timed a video of my test since I didn't remember the numbers. M monotube filled at the pad with active chilling via regulated vent took 1.5 min between start of fill and smoke out the nozzle. We were pulsing the fill so it could have gone faster. Most of the time was chilldown not fill. If it were not a chilled system, it could have been much quicker. So yep, fill at the pad can be pretty fast. Perhaps 30 seconds for a conventional M, half that for an L?

I was using borrowed GSE as I didn't have my own at that time. I think it had a high flow solinoid valve but I'm not certain. I think I recall an M Contrail taking about 30 seconds also when I burned one some years ago. But I'll take corrections on the numbers. I do remember it being hard to tell when it was full, unlike the active chilling where one can easily hear and see the difference due to the valve opening and closing and the bigger puffs when it pops briefly open.

If GSE is resident at a pad so it doesn't have to be set up and removed for each launch, then launches ought to go pretty quickly. It would be nice to go to a launch that had a hybrid pad set up. Might need multiple tanks if it got popular!

 

[ContrailRockets]

I don't have the motors any
Dose Contrail have a newer up dated web site?

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.