HPR CATO

I recently launched an HPR rocket and it barely made it off the launch rail after experiencing some sort of engine difficulty. The staff at the launch site said the failure was caused by a bulkhead that failed and allowed the engine to go through the vehicle's body but I'm not sure that I fully understand what happened and I have some doubts. If anyone could let me know what they think about what might have happened I would be greatly appreciate it.

A video of the failure can be found here https://livestream.com/systemsgo/Rockets2019CTXDay4/videos/190893380 at a time stamp of 2:14:30 (Rocket #114). This video link will most likely not work after May 17.

Rocket Specs
Vehicle Engine: Hyper Tek J190 with .098" orrifice and JFX fuel grain
Vehicle weight: 7.7 Lbs
Vehicle Lenght: 62.5"

Images


Remains of the Rocket


Vehicle waiting to be launched


Vehicle disassembled after completion

I can’t get to that time on the recording without waiting for the entire thing to load, so I can only guess. Pictures showing all the parts lined up as they would have been in the rocket would really help.
Based on the rather sketchy description I’m guessing that the aft-most centering ring failed under thrust (or when the zip tie failed that holds the Hypertek motor onto the nitrous stinger), allowing the motor to travel up into the rocket and cause damage. Did that centering ring break free of the epoxy holding it to the body tube? Did that centering ring simply fail under thrust? From the pictures and description it’s hard to say. Did the motor stay together as it passed through the motor mount tube or was it just the nitrous tank that let go?
Usually the aft most centering ring in the motor mount is up tight against the fin tabs. The fin tabs thus support the ring and transmit thrust to the rocket body. Did you construction include fin tabs or were the fins surface mounted? The fillets left on the side of the rocket appear to be surface mount. The thrust ring on whatever rocket motor you use is close against the centering ring or against the inside of a motor retainer. The motor mount construction must be strong enough to handle the thrust of the motor. In fact, it should be quite a bit stronger in case of chuffing or some failure that allows the motor to slam into the motor mount.
What are your doubts? What are you questioning about what they told you?
How was the motor retained?
Did the zip tie fail while nitrous filling or did it hold until the launch button was pressed?
Do you have pictures showing the aft end of the rocket with your motor retention and the motor mount construction?
I see part of a centering ring from the motor mount peeking out of the first photo. It appears broken, but a great portion of the visible outside edge appears smooth, as if the epoxy (I presume you used epoxy) came loose cleanly. Can you show us some close up pictures of that ring and where it fit in the body?
How did you prep for epoxy?

First thing is I don't know anything about hybrids so I can't speak to that. However, it looks like you didn't get much thrust off the pad. And the video doesn't help a lot as all we see is the rocket leaving the pad - slowly; and then reenter the frame a few seconds later as it crashes. Did you have at least 3:1 thrust to weight ratio at liftoff? That is a minimum and you really should have at least 5:1. Off the top of my head a 7.7 pound rocket on a J190 seems like a poor combination.

Did the nose stay on the entire flight? It looks like it did, which makes the claim that the motor pushed up through the body dubious to me.

A J190 should burn for a long time. Based on the video I assume your motor was not burning as the rocket hit the ground a few seconds after launch? It looks like you had some sort of motor problem (along with other issues).

In the last photo I see what looks like a centering ring underneath he motor. Is that removable? I like what Steve said in his post above, how robust was your motor mount and fin can? This should be solid and not have removable parts if at all possible. I have seen college teams with modular designs so they can easily replace broken parts. Ironically, this is where failures occur because the design that allows things to be disassembled is not strong enough to hold things together under high thrust.

it looks like it only flew on the liquid nitrous. Looks like your altimeter(s) did not go high or fast enough to arm?

Tony (not a hybrid guy)

Looks to me like you had an ignition failure and cold flow. That doesn't produce a whole lot of thrust, and goes through the nitrous faster than would be the case during a burn. Essentially it is like a water rocket.

When nitrous exits the injector it has tremendous cooling potential. Think of it as a dry ice maker. Nitrous and CO2 behave identically that way. If the preheater doesn't put out enough heat fast enough, the nitrous flow will extinguish the flame. Nitrous does put out a lot of heat once it starts to burn, but it takes some heat to get it going in the first place.

I had a cold start transitioning to full thrust on an EX hybrid static test. It was a bigger motor than this one you used. I computed the power requirement for guaranteed instant-on ignition, worst case. It came out to roughly half a megawatt. My preheater was an order of magnitude too low for guaranteed instant ignition. But it was enough to get it going after the first few seconds of cold flow. So the motor went from cold flow (essentially no combustion) to hot flow (nitrous burning but fuel grain warming up) to full burn (fuel burning in the hot nitrous).

If you had a better video you might then see if the motor went through these stages towards generating thrust, or if it just stayed in the cold flow mode.

With that size motor, your injector probably has an area on the order of 1/100 in^2 give or take a chunk. The nitrous pressure was probably on the order of 800psi. So you probably had on the order of 8 pounds of thrust in cold flow water-rocket mode. Yes, I over-simplified.

Since there was no back pressure due to combustion, you went through the nitrous in roughly half the time of the intended burn duration. Pressure in the combustion chamber reduces the pressure drop across the injector(s) which slows the flow.

Cold flow dumps your oxidizer quickly, but doesn't get you very far.

Safety note - If the fuel grain is completely unburned, it is still trash. It isn't worth the risk of burning it in a motor. People have CATO'd hybrids by making that mistake. The grains can typically absorb some nitrous. Then on the next burn (if soon enough) the fuel is much more energetic than design specs. Nitrous is also a solvent of sorts and can attack various things - things which might be in your fuel grain. That potentially alters the properties. Lastly, the initial heating followed by very rapid refrigeration can cause micro cracks in the fuel which is not ideal. So consider the grain to be trash.

Even the O-rings need to be replaced.

I'm guessing your rocket damage occurred on impact with the ground.

Gerald

I made a recording of the flight and I agree with (tfish) Tony and Gerald's excellent explanation. In the video you can clearly see it's just the nitrous venting out the back near the end of the vertical flight - there is no exhaust. It seems the launch failed because the motor essentially 'chuffed' - ignited for a brief moment and then went out. (Well, the LOX has to ignite and burn through the zip ties to allow the nitrous to flow, and for a few frames it does look like there is some exhaust.)

When I flew hybrids I always used break wire launch detection (available on my RDAS compact) for exactly this type of issue, and also the fact that some accelerometer based altimeters would fail to detect launch due to the pulsed nature of hybrid motors. It was not uncommon to see the type of failure experienced by the OP. It was usually caused by an incomplete fill - the motor had enough pressure to ignite and break the zip ties, but not enough for sustained flight. With a break wire it would arm the altimeter after just a couple of feet of vertical movement.

I'm happy to send a copy of the video to anyone that would like it.


Tony

Tony,
I would like to see the video, please. Thanks for doing that. I’ll pm my email address.

I'd agree that this looks like partial ignition, followed by a cold flow event. The person that I have seen who has had great success with Hypertek motors uses fine steel wool at the head end so that when the GOX is flowing and the spark igniter fires there is a large red hot mass to decompose the incoming nitrous.

Edward

AlphaHybrids said:

I'd agree that this looks like partial ignition, followed by a cold flow event. The person that I have seen who has had great success with Hypertek motors uses fine steel wool at the head end so that when the GOX is flowing and the spark igniter fires there is a large red hot mass to decompose the incoming nitrous.

Edward

Click to expand...

The video clearly supports the cold-flow analysis presented here. I'd say the OP's doubts of the analysis given by the staff were warranted. That doesn't mean there weren't construction issues, but at least they don't look like they had anything to do with the motor failure.


Tony

As someone who's never flown a hybrid, I can't comment on any potential motor failure modes which may have occurred. However, looking at the one image of the remains of the rocket, it seems likely that construction problems were present in the rocket itself. The one visible centering ring doesn't appear to have any adhesive on it (either on the inside or outside), I see no evidence of the motor mount tube anywhere, and the fins appear to be surface mounted, instead of through-wall, and not particularly well secured, given how they appear to have broken off. I would be concerned about most of those things on even a nominal flight of the rocket on that motor (especially the fin mounting)

That rocket was built as part of a science and engineering program called 'SystemsGo'. My son participated in it and unfortunately I was not very impressed with the program. I was president of our high school's engineering booster club and saw it up close. It has good intentions but at least in my experience it is poorly implemented. That rocket is pretty comparable to what I saw.


Tony

1. The one remaining centering ring is only intact because it was used as an engine retainer and was bolted to another centering ring that was epoxied into the body. You can see the remains still bolted on the left upper part of the ring visible by the body.

The lip on the end of the fuel grain would have been held between the two rings, the right ring being the one epoxied in and the left one bolted to the right one and seen in the picture of the remains.



2. Upon inspection of the fuel grain it seemed that the flame went out soon after ignition. The only burnt areas were around the nozzle and an inch or two inside from the nozzle

3. Here are the pieces recovered laid out approximately where they would have been in the rocket.


I do have rock sim files and a 3D CAD model of the rocket if anyone would like to see those.

So that would support the conclusion of cold flow as the primary failure cause. However, I'm still concerned about the overall design and construction of the rocket. It appears that no motor mount tube was used (based on the absence of one in the wreckage and the CAD model), and that the centering rings were poorly bonded to the airframe (I can still see laser char on the outer surface of each ring). A rocket this size also really should have through-wall fins so they don't snap off so easily

My team and I are new to all this and didn't really know what we were doing. What should I have done to better secure the centering rings and bulkheads? Also yes there wasn't a motor mount tube but the fins only broke off on impact.

pro

jjwb22101 said:

So that would support the conclusion of cold flow as the primary failure cause. However, I'm still concerned about the overall design and construction of the rocket. It appears that no motor mount tube was used (based on the absence of one in the wreckage and the CAD model), and that the centering rings were poorly bonded to the airframe (I can still see laser char on the outer surface of each ring). A rocket this size also really should have through-wall fins so they don't snap off so easily

Click to expand...

There are many far larger and heaver rockets with surface mounted fins that do just fine. You'll find many 4" MD diameter rockets with nothing more than surface mounted fins that survive Mach 2+. Heavy motors cases are a concern on landing but that can be mitigated with the right parachute.

I have a 54mm MD diameter rocket that I flew on many Hypertek motors exactly as pictured by the OP with just surface mount fins. It's still flying over 15 years later on motors like the AT K1103X.


Tony

manixFan said:

pro
There are many far larger and heaver rockets with surface mounted fins that do just fine. You'll find many 4" MD diameter rockets with nothing more than surface mounted fins that survive Mach 2+. Heavy motors cases are a concern on landing but that can be mitigated with the right parachute.

I have a 54mm MD diameter rocket that I flew on many Hypertek motors exactly as pictured by the OP with just surface mount fins. It's still flying over 15 years later on motors like the AT K1103X.


Tony

Click to expand...

Yes, there are larger and heavier rockets with surface mounted fins. However, the vast majority of those are tip-to-tip fiberglassed, or at the very least, the surfaces are well-prepared prior to bonding, and are only surface-mount out of necessity (as you said, minimum diameter projects). Through-wall mounting is always going to be stronger than a surface mounted fin (assuming they're mounted using the same techniques and adhesives), and tends to be a lot more forgiving.

Colonel_Hogan said:

My team and I are new to all this and didn't really know what we were doing. What should I have done to better secure the centering rings and bulkheads? Also yes there wasn't a motor mount tube but the fins only broke off on impact.

Click to expand...

When wood is laser cut, the darkened (charred) edges of the parts are chemically changed and much weaker than the original wood. They also don't accept most glues or epoxies as well as the un-burnt wood. Because of this, in order to have the strongest possible joints, these parts should ideally be cut slightly too large, and sanded down to fit (enough to remove the charred surface). Also, because epoxy is a surface joint only (it doesn't absorb into materials like wood glue or CA does), it requires that the surface being bonded to be sanded rough, to give maximum area for adhesion (I usually use 150 grit sandpaper when I'm not bonding composites). Based on the way the epoxy joint on the fin popped clean off of the tubing, I would guess that it wasn't sanded nearly enough to get good adhesion.

Speaking of the fins, what material are those made of? It looks like some sort of a plastic to me, which isn't ideal for a hpr rocket. They'll probably work fine for a nominal flight on that motor, but I'd be concerned about them breaking on landing - plastic has a nasty habit of fracturing instead of bending.

Honestly, what most concerns me about this whole thing is your admission that you didn't really know what you were doing. That's a cause to take a deep breath, and a big step back. I would suggest getting a 4" cardboard rocket kit (something like a Binder Excel or LOC Goblin), building it, and flying it on a small H motor with a local NAR or TRA section to get a sense of how HPR rockets are designed, built, and flown. Then, talk to the people at the launch, and get advice from them about your hybrid project.

Seems to me as if the CRs would have been just fine for a nominal flight, same for the fins.

Motor problem caused ground impact on a plywood and bluetube bird, that's going to end you.

I'm not suggesting it couldn't have been made stronger, but I am thinking probably it was reasonably constructed.

jjwb22101 said:

..<snipped>...Honestly, what most concerns me about this whole thing is your admission that you didn't really know what you were doing. That's a cause to take a deep breath, and a big step back. I would suggest getting a 4" cardboard rocket kit (something like a Binder Excel or LOC Goblin), building it, and flying it on a small H motor with a local NAR or TRA section to get a sense of how HPR rockets are designed, built, and flown. Then, talk to the people at the launch, and get advice from them about your hybrid project.

Click to expand...

I don't think you understand the situation here at all. This launch was part of a STEM program called 'SystemsGo'. It's typically part of a physics class and the kids are essentially told to build a rocket and are supposed to 'discover' or figure it out on their own with very little supervision. They get to build one rocket and launch it once, that's it. No starting small and working their way up. They don't get a kit and can't use one. They are required to use hybrid motors.

As I mentioned, my son participated in the program when he was in school. I was president of our school's engineering booster club and worked with the program. I was told by the folks that run the program that I was providing too much assistance and to quit helping the students. The teachers give them some info but are not actively involved in helping the students either. None of kids I asked could answer even the most basic questions about rockets and they were supposed to figure everything out through research. But there were no checks and balances and most of the teachers knew nothing about the rockets either. You can imagine what the success rate is like. In the end the students learned very little and almost nothing about how real engineering works.

So, yes, these kids don't know what they are doing and we're not supposed to help them. They followed the guidelines of the program and their results are typical of what I saw. They are doing it because it's part of the class, not an optional activity. In reality most of the work gets done by a few interested students and the rest don't really care.

I wasn't planning on getting up on my soapbox about it but your comments showed you weren't aware of the OP's situation and were taking him to task for something that was beyond his control. The fact he came here and asked for more info is far more than most others would have done.


Tony

I know very little about hybrids but why is it venting before ignition? Something is venting way before they hit the button.
Steve

manixFan said:

I don't think you understand the situation here at all. This launch was part of a STEM program called 'SystemsGo'. It's typically part of a physics class and the kids are essentially told to build a rocket and are supposed to 'discover' or figure it out on their own with very little supervision. They get to build one rocket and launch it once, that's it. No starting small and working their way up. They don't get a kit and can't use one. They are required to use hybrid motors.

As I mentioned, my son participated in the program when he was in school. I was president of our school's engineering booster club and worked with the program. I was told by the folks that run the program that I was providing too much assistance and to quit helping the students. The teachers give them some info but are not actively involved in helping the students either. None of kids I asked could answer even the most basic questions about rockets and they were supposed to figure everything out through research. But there were no checks and balances and most of the teachers knew nothing about the rockets either. You can imagine what the success rate is like. In the end the students learned very little and almost nothing about how real engineering works.

So, yes, these kids don't know what they are doing and we're not supposed to help them. They followed the guidelines of the program and their results are typical of what I saw. They are doing it because it's part of the class, not an optional activity. In reality most of the work gets done by a few interested students and the rest don't really care.

I wasn't planning on getting up on my soapbox about it but your comments showed you weren't aware of the OP's situation and were taking him to task for something that was beyond his control. The fact he came here and asked for more info is far more than most others would have done.


Tony

Click to expand...

Thanks for that, I'm sure more than a few of us were scratching our heads. Sounds like a recipe for a mishap.

manixFan said:

I don't think you understand the situation here at all. This launch was part of a STEM program called 'SystemsGo'. It's typically part of a physics class and the kids are essentially told to build a rocket and are supposed to 'discover' or figure it out on their own with very little supervision. They get to build one rocket and launch it once, that's it. No starting small and working their way up. They don't get a kit and can't use one. They are required to use hybrid motors.

As I mentioned, my son participated in the program when he was in school. I was president of our school's engineering booster club and worked with the program. I was told by the folks that run the program that I was providing too much assistance and to quit helping the students. The teachers give them some info but are not actively involved in helping the students either. None of kids I asked could answer even the most basic questions about rockets and they were supposed to figure everything out through research. But there were no checks and balances and most of the teachers knew nothing about the rockets either. You can imagine what the success rate is like. In the end the students learned very little and almost nothing about how real engineering works.

So, yes, these kids don't know what they are doing and we're not supposed to help them. They followed the guidelines of the program and their results are typical of what I saw. They are doing it because it's part of the class, not an optional activity. In reality most of the work gets done by a few interested students and the rest don't really care.

I wasn't planning on getting up on my soapbox about it but your comments showed you weren't aware of the OP's situation and were taking him to task for something that was beyond his control. The fact he came here and asked for more info is far more than most others would have done.


Tony

Click to expand...

Banzai88 said:

Thanks for that, I'm sure more than a few of us were scratching our heads. Sounds like a recipe for a mishap.

Click to expand...

There seems to be more and more of these "throw them in the deep end to teach them to swim" programs coming along. This one appears to have been confined to a specific region and scheduled their own launches as part of the program. Others just put some task out there for anyone to sign up for. Unfortunately, many of these challenges rely on the students finding a place to fly on their own and, in many cases, they turn to clubs in their areas. While this should be a great opportunity for a club to enroll new members and for the students to pick up useful knowledge, more times than not, it's a one-time shot with little warning. Generally, the flyers have little to no experience but "the sim says" the tiny fins will do the job and "we need to get this up in the air so we can write a report by tomorrow night". Much of this could be helped if the students would contact their local club(s) at the beginning of the process rather than just show up. But I can't make teenagers act more responsibly or stop promoters from coming up with harebrained contests.

What I can do is put together some guidelines for my clubs to use when dealing with such groups. NAR sanctioned events are one thing and we still want the participants to demonstrate some level of skill before forging ahead. The non-NAR events need extra scrutiny because we can't afford any mishaps that would cost us our fields.

SDramstad said:

I know very little about hybrids but why is it venting before ignition? Something is venting way before they hit the button.
Steve

Click to expand...

Hybrids are usually placed on the pad without nitrous and then filled on the pad from a safe distance. While filling, the nitrous tank must vent to the atmosphere. It’s common to see gaseous nitrous exiting the nitrous tank during the filling. When the gas turns to liquid the tank is filled.

To elaborate on Steve’s explanation, the venting of nitrous is essentially a thermal control. It allows enough gas expansion in the filling process that removes heat from the nitrous. This lowers the temperature of the rocket’s tank contents hence lowers its pressure equilibrium to provide a pressure differential for faster, safer and easier (self-feeding) transfer of the nitrous from the supply vessel to the rocket’s tank.
An added bonus with a lower N2O temperature is an increase in bulk density ie. more nitrous in the tank’s usable volume. The larger your vent hole, the lower the equilibrium temperature of your received N2O but the more lost N2O from the venting process.
If you had no vent in your receiving tank and either pumped or gravity fed your N2O into it, the receiving tank would actually heat up initially as the pressure in it rises.

TP

The people in charge of the launch should consider tightening up their RSO procedures. Allowing people who don't know what they are doing to launch a hybrid rocket is asking for trouble.

I understand supporting student projects as my club has college teams at many of our high power launches. The success rate for these teams has not been good and we are always discussing what can we do to assist these teams without being intrusive or denying them access to our launches. We now make it very clear that we will be conducting a safety check on their rocket and if the RSO says no, they are not flying. The team that launched a 50 pound rocket at our launch on Sunday had several failures on their shakedown flight.

We should have suspected that there were going to be problems when they had the rocket on the pad and even using an 8 foot tall stepladder they couldn't reach the avbay to turn on their electronics.

Zeus-cat said:

The people in charge of the launch should consider tightening up their RSO procedures. Allowing people who don't know what they are doing to launch a hybrid rocket is asking for trouble. ...<snipped>...

Click to expand...

See post 18. The way the program is designed they get to build one rocket and launch it once. There is no way for them to got to 'know what they are doing'. However, the staff handles all the motors and launch procedures so the kids aren't involved in the actual launch. If you watch the video you'll hear constant safety warnings, including to not try and recover the rocket - the staff does that as well to make sure everything is safe.

So it's not a launch format that we are used to. These kids aren't hobbyists looking to gain experience flying model rockets. It's a class assignment and gets treated as such.


Tony

jjwb22101 said:

. Also, because epoxy is a surface joint only (it doesn't absorb into materials like wood glue or CA does), it requires that the surface being bonded to be sanded rough, to give maximum area for adhesion (I usually use 150 grit sandpaper when I'm not bonding composites). Based on the way the epoxy joint on the fin popped clean off of the tubing, I would guess that it wasn't sanded nearly enough to get good adhesion.

Speaking of the fins, what material are those made of? It looks like some sort of a plastic to me, which isn't ideal for a hpr rocket. They'll probably work fine for a nominal flight on that motor, but I'd be concerned about them breaking on landing - plastic has a nasty habit of fracturing instead of bending.

Click to expand...

Whoa whoa whoa, don't fall off that high horse and let that bag of rocks you are throwing land on you on the way down.

Epoxy is not a surface joint. It is a liquid that through a chemical reaction becomes a solid. Depending on the viscosity of the liquid epoxy and the porosity of the substrate it can soak into and provide an excellent bond. Think of fiberglass fabric. Porous matrix that epoxy soaks into. Or plywood. Or fabric. Shop towels. You get my point. Let's not make blanket statements here.

The material of the fins matters very little, just that they are designed to withstand the flight. I have a rocket that uses 1/4" HDPE fins on K/L motors because that is the material I had around. The rocket reaches around Mach 0.7. Great fins. And, I would say plastic, by it's very nature, is a plastic material. It has the property of bending to it's yield point and then coming back to shape - some would say it possesses plasticity!

Edward

AlphaHybrids said:

Whoa whoa whoa, don't fall off that high horse and let that bag of rocks you are throwing land on you on the way down.

Epoxy is not a surface joint. It is a liquid that through a chemical reaction becomes a solid. Depending on the viscosity of the liquid epoxy and the porosity of the substrate it can soak into and provide an excellent bond. Think of fiberglass fabric. Porous matrix that epoxy soaks into. Or plywood. Or fabric. Shop towels. You get my point. Let's not make blanket statements here.

The material of the fins matters very little, just that they are designed to withstand the flight. I have a rocket that uses 1/4" HDPE fins on K/L motors because that is the material I had around. The rocket reaches around Mach 0.7. Great fins. And, I would say plastic, by it's very nature, is a plastic material. It has the property of bending to it's yield point and then coming back to shape - some would say it possesses plasticity!

Edward

Click to expand...

re. epoxy - fair. I was a bit too general in my assertions. It'll soak into fabrics and other such highly porous substrates, but my point still stands re. the materials they were using. A thick epoxy like the one they were using won't soak into plywood or blue tube.

I agree about fins, for a nominal flight they probably would have been fine, but I'm all about education, and plastic is almost never an ideal fin material - a good quality birch ply or fiberglass fin would be better in just about any case - it would be lighter, stronger, easier to bond, etc.

manixFan said:

I don't think you understand the situation here at all. This launch was part of a STEM program called 'SystemsGo'. It's typically part of a physics class and the kids are essentially told to build a rocket and are supposed to 'discover' or figure it out on their own with very little supervision. They get to build one rocket and launch it once, that's it. No starting small and working their way up. They don't get a kit and can't use one. They are required to use hybrid motors.

As I mentioned, my son participated in the program when he was in school. I was president of our school's engineering booster club and worked with the program. I was told by the folks that run the program that I was providing too much assistance and to quit helping the students. The teachers give them some info but are not actively involved in helping the students either. None of kids I asked could answer even the most basic questions about rockets and they were supposed to figure everything out through research. But there were no checks and balances and most of the teachers knew nothing about the rockets either. You can imagine what the success rate is like. In the end the students learned very little and almost nothing about how real engineering works.

So, yes, these kids don't know what they are doing and we're not supposed to help them. They followed the guidelines of the program and their results are typical of what I saw. They are doing it because it's part of the class, not an optional activity. In reality most of the work gets done by a few interested students and the rest don't really care.

I wasn't planning on getting up on my soapbox about it but your comments showed you weren't aware of the OP's situation and were taking him to task for something that was beyond his control. The fact he came here and asked for more info is far more than most others would have done.

Tony

Click to expand...

Thanks for the info - I wasn't familiar with the program, and decided to do a bit of research. The timeline for the development and flight of these rockets is INCREDIBLY short - as someone who's participated in school competition rocketry for 8 years now, even a full school year is scarcely enough time to design, order, build, refine, and fly a high power rocket for this sort of thing, let alone a single semester (and that's with years of experience doing this!). I'm also concerned that this program appears to have no affiliation with either of the major sport rocketry organizations to provide mentorship and assistance to the students, and make sure that operations proceed in a safe manner. This seems like something where someone should reach out to the program directors on behalf of NAR or TRA and offer to provide assistance with this sort of program.

manixFan said:

See post 18. The way the program is designed they get to build one rocket and launch it once. There is no way for them to got to 'know what they are doing'. However, the staff handles all the motors and launch procedures so the kids aren't involved in the actual launch. If you watch the video you'll hear constant safety warnings, including to not try and recover the rocket - the staff does that as well to make sure everything is safe.

So it's not a launch format that we are used to. These kids aren't hobbyists looking to gain experience flying model rockets. It's a class assignment and gets treated as such.


Tony

Click to expand...

I am not trying to bash you as I am sure that there are a lot of details we haven't seen, but I am wondering why anyone would allow this at an organized launch. From what has been presented in this thread I see very little to be gained by allowing this.

If this was my club I would seriously consider telling the school that we don't want to be involved and they can go find another launch site. For safety reasons alone this just sounds like a really bad idea. Under any other circumstances what RSO would approve such a complex rocket for flight by people that have very little idea of what they are doing?

I realize the school is setting the format for this assignment, but you don't need to agree to let the rocket be launched at your event by people that are not qualified to launch it. As you said, the kids don't learn much; so why support it?

Zeus-cat said:

...<snip>... If this was my club I would seriously consider telling the school that we don't want to be involved and they can go find another launch site...<snip>...

Click to expand...

Ok, you’re still missing the point. They have their own launch site staffed by their own volunteers. It’s not a club launch. No NRA or TRA. The organization charges schools a fee for the curriculum and to participate in the launch. The students are supposed to do everything themselves without any real supervision. Except once at the field all the launch duties are handled by staff.


Tony

I'm amazed that they haven't seriously injured or killed anyone yet. I also wonder what their measure of success of the program is?
Based on the cowboy crap that I've seen at rocket fields by people that actually supposedly know what they're doing (which invariably ends in disaster), this seems like Russian Roulette with 5 bullets in a single gun.

In the last 5 years since BAR I've seen a tremendous amount of college students show up at our club launches with half or half-ass built rockets, zero clues, and a metric butt ton of desire to get an L1 cert flight in so that they can participate in their university rocketry projects. By and far, they're clueless. Without exception, whatever club I'm launching with, we rally around those kids, pool resources, offer advice, and by the end of the day they're not only L1 certified, but they have a complete, safe, reusable rocket and more understanding of the rocket, the physics, and the safety than they showed up with. I hope that it's an example that lasts them a lifetime. Many show up at later launches with their rocket refined and painted and launch again....for their own satisfaction. Those are the core of the 'team' that I usually see doing all of the work on college launch day.

The point being that it doesn't take very much effort, or very long, to get these kids the right information, mentorship, and support to ACTUALLY learn something useful. Despite this program looking like a missed opportunity, I hope that the kids get something meaningful out of it.