BALLS Flights

[Steve Shannon]

Not at extremely high altitude they can't. AFAIK, BP efficiency in near vacuum is difficult if not impossible to quantify, though various containment techniques have proved to be workable.

I agree that high altitudes add complexity to BP charges, but both Tony Alcocer and Jim Jarvis have done great work getting BP charges to work reliably. The calculation for how much BP to use doesn’t really have to change; a reliable method of igniting it all rather than having it scattered is necessary. If you haven’t seen it, here is a a great article by Tony. In particular pay attention beginning at post #9:
98mm min dia high altitude deployment
https://www.rocketryforum.com/index.php?threads/98mm-min-dia-high-altitude-deployment.152590/

 

[jderimig]

Not at extremely high altitude they can't. AFAIK, BP efficiency in near vacuum is difficult if not impossible to quantify, though various containment techniques have proved to be workable.

Very easy to measure at home with a pvc pressure vessel, vacuum pump and a $10 eBay pressure transducer.

 

[JimJarvis50]

Not at extremely high altitude they can't. AFAIK, BP efficiency in near vacuum is difficult if not impossible to quantify, though various containment techniques have proved to be workable.

The link that Steve posted (from TFish) includes a link to the high altitude BP method I use. Just copied it below.

https://www.rocketryfiles.com/files/Technicalarticles/Jim_Jarvis_Highaltitude_deployment_2013.pdf

That method, as well as the modified TFish method, result in consuming all of the BP. Therefore, the charges work exactly the same in space as they do on the ground - no guesswork required to figure out how the charges will work. That is a significant advantage relative to methods that might not result in 100% consumption.

Jim

 

[Kip_Daugirdas]

This thread is proving my point. Not everyone here understands how to select a charge design and size charges for for a high-altitude flight. There’s good and misleading information posted. Regardless, selecting a deployment method takes research, testing and a good chunk of time. Something a few Class 3 flyers clearly do not take the effort to complete.

Same goes for designing a recovery system to incorporate a main parachute. It’s way easier to just worry about one set of charges and one chute (a drogue) than design a compact dual deployment system.

I’ll reiterate that these projects are easy to pick out just by asking a few questions. But instead of reviewing/finding this out a week before Balls and not letting the individuals fly and enticing a bunch of drama, we could complete reviews earlier and get the fixes implemented before Balls, etc. Everyone’s happy.

Charges and recovery system design is all captured by the Class 2/3 paperwork. Instead of worrying about dispersion alone a separate review can be completed by an experienced team in advance.

Why wouldn’t we do this?

 

[tfish]

Very easy to measure at home with a pvc pressure vessel, vacuum pump and a $10 eBay pressure transducer.

John, Jim and I help out with Spaceport America Cup and last year we had a team with a 2 stage project going to 125K. They realized BP at high altitude could be troublesome. They did some testing with a PVC test vessel, gauges and a vacuum pump. They came up with 4 gram charge for their project. Their charge holder was very short. They did a test flight to 25K and claimed it worked at 25 so it would work at 125K. Neither Jim nor I could put our finger on what was missing from their testing. They had numbers and figures but it did not seem like it would work. We had been showing them other proven methods but they would not listen. We ended up putting their flight on "probation" until we could meet up at Spaceport. Out at Spaceport we had a chance to do some show and tell. I made up a 4 gram charge using the vinyl tube method and placed a cinder block to hold the igniter leads in place. At zero half the cinder block flew about 15 feet away. The team was very surprised at how powerful the charge was. They said their charge was no where near as powerful as that one was..

The moral of the story is...be careful of what you think your testing is proving. Ask others for help and or advise...even if you think you don't need it.

Tony

 

[mikec]

The link that Steve posted (from TFish) includes a link to the high altitude BP method I use.

Yes, and I've read it many times and followed all its advice as best I could (and then I put in a larger backup charge for margin). But the very first section says that the "standard" surgical tubing doesn't work. If you keep reading in the tfish thread above you'll see some modifications that Tony came up with that Jim mentions. But all of this, IMHO, falls short of a best-practices guideline, much less a hard "you have to do it this way" requirement. It would certainly be helpful to develop something like that.

As Kip says, the week before BALLS, or during RSO review at BALLS, is the wrong time to be looking at this. Clearly there were some apogee deployment failures this year that need to be understood.

 

[jderimig]

John, Jim and I help out with Spaceport America Cup and last year we had a team with a 2 stage project going to 125K. They realized BP at high altitude could be troublesome. They did some testing with a PVC test vessel, gauges and a vacuum pump. They came up with 4 gram charge for their project. Their charge holder was very short. They did a test flight to 25K and claimed it worked at 25 so it would work at 125K. Neither Jim nor I could put our finger on what was missing from their testing. They had numbers and figures but it did not seem like it would work. We had been showing them other proven methods but they would not listen. We ended up putting their flight on "probation" until we could meet up at Spaceport. Out at Spaceport we had a chance to do some show and tell. I made up a 4 gram charge using the vinyl tube method and placed a cinder block to hold the igniter leads in place. At zero half the cinder block flew about 15 feet away. The team was very surprised at how powerful the charge was. They said their charge was no where near as powerful as that one was..

The moral of the story is...be careful of what you think your testing is proving. Ask others for help and or advise...even if you think you don't need it.

Tony

I did both. I followed your and Jim's method and tested it on the ground under vacuum. Trust but verify...

 

[Steve Shannon]

This thread is proving my point. Not everyone here understands how to select a charge design and size charges for for a high-altitude flight. There’s good and misleading information posted. Regardless, selecting a deployment method takes research, testing and a good chunk of time. Something a few Class 3 flyers clearly do not take the effort to complete.

Same goes for designing a recovery system to incorporate a main parachute. It’s way easier to just worry about one set of charges and one chute (a drogue) than design a compact dual deployment system.

I’ll reiterate that these projects are easy to pick out just by asking a few questions. But instead of reviewing/finding this out a week before Balls and not letting the individuals fly and enticing a bunch of drama, we could complete reviews earlier and get the fixes implemented before Balls, etc. Everyone’s happy.

Charges and recovery system design is all captured by the Class 2/3 paperwork. Instead of worrying about dispersion alone a separate review can be completed by an experienced team in advance.

Why wouldn’t we do this?

Actually there’s a lot more that isn’t captured by the 50k/Class 3 paperwork and there are lots of things going in the months leading up to BALLS. I didn’t see any of the Class 3 work until I was sitting in the airport at Wichita waiting for my flight home from LDRS.
Also, the review by the board this year was not intended as an engineering review. It was there as a last minute check to prevent the kind of problems we had the year before and protect the event. You’re expected to have your own engineering done well in advance. If you’ve done a good job of it the board review won’t be a problem. I absolutely agree that it would be great to have all engineering reviews nailed down a month beforehand. Gerald will be leading an ad hoc committee to make suggestions.

 

[cwbullet]

Actually there’s a lot more that isn’t captured by the 50k/Class 3 paperwork and there are lots of things going in the months leading up to BALLS. I didn’t see any of the Class 3 work until I was sitting in the airport at Wichita waiting for my flight home from LDRS.
Also, the review by the board this year was not intended as an engineering review. It was there as a last minute check to prevent the kind of problems we had the year before and protect the event. You’re expected to have your own engineering done well in advance. If you’ve done a good job of it the board review won’t be a problem. I absolutely agree that it would be great to have all engineering reviews nailed down a month beforehand. Gerald will be leading an ad hoc committee to make suggestions.

Steve: I really appreciate this discussion. I am learning a lot that will help out club and we do not fly above 50K. I review TRA policy and I do not see the concept of a safety stop. Have you thought about this concept to review unsuccessfully flights?

 

[JimJarvis50]

I did both. I followed your and Jim's method and tested it on the ground under vacuum. Trust but verify...

Good point. In the situation Tony mentioned at Spaceport, I provided some guidance to the team on how the charges should be constructed. As Tony mentioned, they were 4 gram charges, and I had them put the ematch at the bottom of the charge as I do in my method (where my recommendation is to limit the charge size to about 1.5 grams). A little voice told me I needed to check out my recommendation given the change away from my own experience base. So a day or so before we traveled to Spaceport, I dug out the vacuum chamber and did some testing. To my suprise, the charges didn't work. It turns out that when the charge gets long enough, the powder will disperse. The fix is to put the ematch on the top of the powder, as Tony recommends, or at least closer to the top of the powder, as I do now on my flights. The team didn't make it to 125K, but I'm glad I did the "verify" part. There are things that can go wrong with the high altitude charges, so they should always be ground tested, regardless of anyone's confidence that something will work. I guess I should update the method.

Regarding the Class 3 flights, I don't understand why Tripoli doesn't do some minimal review of these projects outside of a dispersion analysis. I've been submitting projects for a while, and no one has ever asked me a question about safety procedures, tilt settings, etc., etc. The Board is supposed to review and approve projects, and no one would get upset if there was actually a review. We reviewed around a hundred projects for Spaceport, many from teams that didn't have a clue. It doesn't seem to me that reviewing 16 projects from folks that generally know what they're doing would be that hard to accomplish.

Jim

 

[Charles_McG]

It doesn't seem to me that reviewing 16 projects from folks that generally know what they're doing would be that hard to accomplish.

Spoken like a prospective reviewer.

(And I really don't seem to sound snarky. You guys are tens of thousands of feet above my league. But it was just too good of a set up for me to resist.)

 

[Steve Shannon]

Steve: I really appreciate this discussion. I am learning a lot that will help out club and we do not fly above 50K. I review TRA policy and I do not see the concept of a safety stop. Have you thought about this concept to review unsuccessfully flights?

Gerald is collecting what data he can and the intent is to review it. Every year after BALLS the board cussed and discusses flights but we need to make such data available for others. Every flight teaches lessons and the most spectacular ones often have many to teach! [emoji3]

 

[Steve Shannon]

Good point. In the situation Tony mentioned at Spaceport, I provided some guidance to the team on how the charges should be constructed. As Tony mentioned, they were 4 gram charges, and I had them put the ematch at the bottom of the charge as I do in my method (where my recommendation is to limit the charge size to about 1.5 grams). A little voice told me I needed to check out my recommendation given the change away from my own experience base. So a day or so before we traveled to Spaceport, I dug out the vacuum chamber and did some testing. To my suprise, the charges didn't work. It turns out that when the charge gets long enough, the powder will disperse. The fix is to put the ematch on the top of the powder, as Tony recommends, or at least closer to the top of the powder, as I do now on my flights. The team didn't make it to 125K, but I'm glad I did the "verify" part. There are things that can go wrong with the high altitude charges, so they should always be ground tested, regardless of anyone's confidence that something will work. I guess I should update the method.

Regarding the Class 3 flights, I don't understand why Tripoli doesn't do some minimal review of these projects outside of a dispersion analysis. I've been submitting projects for a while, and no one has ever asked me a question about safety procedures, tilt settings, etc., etc. The Board is supposed to review and approve projects, and no one would get upset if there was actually a review. We reviewed around a hundred projects for Spaceport, many from teams that didn't have a clue. It doesn't seem to me that reviewing 16 projects from folks that generally know what they're doing would be that hard to accomplish.

Jim

You and Kip and Mike C are correct that this needs to be done. We had hoped to do it this year but the board just didn’t have the time or resources. That’s part of what Skippy’s committee will be trying to develop.

 

[BABAR]

Hospital Physicians have regular conferences, used to be called M and M for Morbidity and Mortality, now goes by Peer Review or other names, where , in a legally protected setting, unexpected patient outcomes and deaths could be discussed. In medicine, as in rocketry, sometimes bad things happen and there is no one at fault. And sometimes someone IS at fault. Point being, mistakes acknowledged, recognized, and shared, help prevent people repeating history, At least in medicine we HOPE that by looking at each of these cases we can learn from them, share that knowledge at least with our local fellow docs, and do better in the future.

Would it work for those fliers that have an “untoward event” to be required to do a write up with lessons learned and plans to NOT do such next year, upon penalty of not being invited back the next year? Heck, throw in a carrot, put the write ups on the website and cast votes for the best write up, with an Auger Inn trophy for best report?

 

[Steve Shannon]

Hospital Physicians have regular conferences, used to be called M and M for Morbidity and Mortality, now goes by Peer Review or other names, where , in a legally protected setting, unexpected patient outcomes and deaths could be discussed. In medicine, as in rocketry, sometimes bad things happen and there is no one at fault. And sometimes someone IS at fault. Point being, mistakes acknowledged, recognized, and shared, help prevent people repeating history, At least in medicine we HOPE that by looking at each of these cases we can learn from them, share that knowledge at least with our local fellow docs, and do better in the future.

Would it work for those fliers that have an “untoward event” to be required to do a write up with lessons learned and plans to NOT do such next year, upon penalty of not being invited back the next year? Heck, throw in a carrot, put the write ups on the website and cast votes for the best write up, with an Auger Inn trophy for best report?

That’s a great idea.

 

[cwbullet]

Hospital Physicians have regular conferences, used to be called M and M for Morbidity and Mortality, now goes by Peer Review or other names, where , in a legally protected setting, unexpected patient outcomes and deaths could be discussed. In medicine, as in rocketry, sometimes bad things happen and there is no one at fault. And sometimes someone IS at fault. Point being, mistakes acknowledged, recognized, and shared, help prevent people repeating history, At least in medicine we HOPE that by looking at each of these cases we can learn from them, share that knowledge at least with our local fellow docs, and do better in the future.

Would it work for those fliers that have an “untoward event” to be required to do a write up with lessons learned and plans to NOT do such next year, upon penalty of not being invited back the next year? Heck, throw in a carrot, put the write ups on the website and cast votes for the best write up, with an Auger Inn trophy for best report?

In the military system, we do the same. Say an eye surgeon puts in the wrong lense and not the patient has less than ideal vision. We approach the case as a learning opportunity. We do what is called a Root Cause Analysis. A safety standdown may occur to allow all staff to focus on the case and dig into all contributing causes. More often than not, we find a system or procedure cause. This approach allows for open discussion without the vilification of the provider or nurse. This will revictimize the provider which is not helpful.

I supervise 400 medical providers and see it all the time. Often, it is a near-miss that never makes it to a patient.

 

[wyo17]

I don't spend much time on TRF, and just got told of this thread tonight. This has been a good read. Thanks to Steve, Kip, and Jim, as well as many others who have posted. Didn't have the money to afford the high dollar altimeters then but successfully flew a 2 stage 4" airframe on a combination of 54mm motors, due to motors altitude restrictions on the East Coast. Best up was an L to an L at Red Glare. When I got into this project I was smart enough to reach out to Jim J for advice. 5 flights later, all good, I was happy. Jim provided some great advice, Thank You.

I bought a Telemega and attempted am M to an K, my bad grossly under powered booster, M1101 to a K365. Tilted too much and the Telemega, set for 10 degrees of angle, version 1.6.8 prevented sustainer ignition.

Recovered intact.

Here is my problem. A friend of mine and I are building a 4" N to an M project, expected altitude of about 35k. He is building the booster and I have the sustainer. Our plan is to lite the sustainer with the telemega.

With that version of the Telemega proven, with angle tilt working, should I update it?

 

[Steve Shannon]

I don't spend much time on TRF, and just got told of this thread tonight. This has been a good read. Thanks to Steve, Kip, and Jim, as well as many others who have posted. Didn't have the money to afford the high dollar altimeters then but successfully flew a 2 stage 4" airframe on a combination of 54mm motors, due to motors altitude restrictions on the East Coast. Best up was an L to an L at Red Glare. When I got into this project I was smart enough to reach out to Jim J for advice. 5 flights later, all good, I was happy. Jim provided some great advice, Thank You.

I bought a Telemega and attempted am M to an K, my bad grossly under powered booster, M1101 to a K365. Tilted too much and the Telemega, set for 10 degrees of angle, version 1.6.8 prevented sustainer ignition.

Recovered intact.

Here is my problem. A friend of mine and I are building a 4" N to an M project, expected altitude of about 35k. He is building the booster and I have the sustainer. Our plan is to lite the sustainer with the telemega.

With that version of the Telemega proven, with angle tilt working, should I update it?

1.8.6 or newer. Current version is 1.9.0

 

[prfesser]

100% concur. TRA has a duty to establish safety policy norms. Everything from material strength, epoxy selection, parachute Cd, even rail button placement, can and should have safe baseline norms tested, determined, and enforced. This is a science and so far, there hasn't been enough science.

This is a very good idea. However...I'm not trying to be snotty, but...will you take the lead on this? Consult the BoD, construct basic norms, run them by the BoD, get committee members, move the whole thing forward?

As one wise rocketeer told me, many moons ago, "The problem with good ideas is that they devolve into a lot of hard work" . A formal, fairly detailed proposal to the BoD would be the first step.

And be careful! Back in 2002 (I think) instead of "Someone should do something", I finally decided that "I should do something". And that turned into a 12-year stint on the BoD...

Best -- Terry

 

[Cameron Anderson]

This is a very good idea. However...I'm not trying to be snotty, but...will you take the lead on this? Consult the BoD, construct basic norms, run them by the BoD, get committee members, move the whole thing forward?

As one wise rocketeer told me, many moons ago, "The problem with good ideas is that they devolve into a lot of hard work" . A formal, fairly detailed proposal to the BoD would be the first step.

And be careful! Back in 2002 (I think) instead of "Someone should do something", I finally decided that "I should do something". And that turned into a 12-year stint on the BoD...

Best -- Terry

I'd be willing to help, to be part of the solution, but my current civilian employment will prevent me from having as active a roll as i would prefer. I tried to start in initiative to catalog flights, thousands of them, to categorize failures and approach rockets with a little more root cause analysis and statistical analysis and I was met with indignation. I think this would be a great opportunity for universities - maybe a grant program for research that the BoD approves?

I've found in HPR a certain reluctance for some flyers to do anything different than the first way they learned something. "Method X is the best because I learned it 10 years ago when I barely understood what I heard and I have done no research or learning since." Breaking that mindset will be tough. Convincing prefects and fliers that some of the commonly held rules of thumb are less than accurate and others are flat wrong.