Check out this Kickstarter...

First, here's the link:

Self-Guided, Helium Assisted, Rocket Program; S.H.A.R.P, via @Kickstarter https://www.kickstarter.com/projects/1097694446/model-rocket-travels-to-space

Be sure to read the comments.

If they weren't all U of U grads... Maybe they can power it with cold fusion!

When people do a poor job of writing up an explanation for why they want your money for the project I get nervous about what they want to do. I mean, this is your ad, it shouldn't have simple mistakes in it when you are telling people you want to do something complicated and potentially dangerous.

For example; the one guy is a physicist enthusiast. So he really likes physicists????

https://www.rocketryforum.com/threads/stupid-kickstarter-campaigns.146694/

Zeus-cat said:

For example; the one guy is a physicist enthusiast. So he really likes physicists????

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Physicists are very likable. <smile>

yet another rockoon project, with no clue as to how to get FAA approval. Of course, if they asked here, they would have been told it wouldn't ever happen

Apparently they haven't heard that being a member of a "rocket club" doesn't give you a pass with the FAA to do whatever you want. Judging by the description of the rocket, i.e. firing on four Estes F15's, my guess is that nobody on the team is HPR certified and has any clue about how to approach a project like this. That fact that they've only raised $12 so far probably means that they're not gonna get off the ground anyway.

CzTeacherMan said:

Be sure to read the comments.

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Hoe. Lee. Crap. That dude Ryan should be muzzled ASAP. And those are his responses to someone WHO GAVE THEM MONEY. Almost beyond belief.

the fact that they consider themselves scientists even though they have not graduated yet (I would guess), leads me to believe that Ryan must have just finished up his "Inflated EGO Class IEC100". He will be a future gem for any colleague he "must" work with.

Sounds like they are fully funded; at least they say so. Let's hope they just give up before they try to do this.

Zeus-cat said:

Sounds like they are fully funded; at least they say so. Let's hope they just give up before they try to do this.

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I think they said they were building with their own money anyway. To me, the kickstarter was just something they thought they may get some money from. Kickstarter will not give them anything unless the "campaign" is fully funded to the $2500 mark. With less than 45 hours left, I would not expect us to all jump on the bandwagon to help out.

Personally, I would rather they go ahead and research how to get the necessary permits, etc and pursue their project. As long as it is all down under legal guidelines, it would be interesting.

neil_w said:

Hoe. Lee. Crap. That dude Ryan should be muzzled ASAP. And those are his responses to someone WHO GAVE THEM MONEY. Almost beyond belief.

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In fearless youth we tempt the heights of Arts...

They are kids.

Those of us in certain parts of North America, and of a certain age, like to think we remember a time when college was not high school for adults and serious students would have had no time for this nonsense.

It is a plausible facsimile of a memory, because there WAS a time when not every high school student was expected or encouraged to go on to college, and when high school's offered a more rigorous course of instruction to the college-bound.

The days of the "serious college student" are a myth. It is just that the kind of folly we got up to covertly is now what gets broadcast on YouTube.

I would not like to say that, if crowdsourcing had existed, that my classmates would not have made some embarrassingly dumbassed proposal about something. We were inventive, and ignorant, and foolish in other ways -- we might have asked strangers to fund our misadventures.

jlabrasca said:

In fearless youth we tempt the heights of Arts...

They are kids.

Those of us in certain parts of North America, and of a certain age, like to think we remember a time when college was not high school for adults and serious students would have had no time for this nonsense.

It is a plausible facsimile of a memory, because there WAS a time when not every high school student was expected or encouraged to go on to college, and when high school's offered a more rigorous course of instruction to the college-bound.

The days of the "serious college student" are a myth. It is just that the kind of folly we got up to covertly is now what gets broadcast on YouTube.

I would not like to say that, if crowdsourcing had existed, that my classmates would not have made some embarrassingly dumbassed proposal about something. We were inventive, and ignorant, and foolish in other ways -- we might have asked strangers to fund our misadventures.

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Good post.

From their description: The reasoning for so much power is because of the amount of mass on the rocket, plus we think its cool! The motors will be linked together in series instead of parallel to maximize success of all engines igniting at once.

This is more evidence they don't know what they are talking about. Motors linked in series to maximize success of all engines? Are they talking about the igniters? If so, only the first one will light unless they get lucky and the second igniter gets enough current to light while the first is lighting, most likely this will not happen.

So much wrong in such a small package. That said, do they NEED a waiver? I've seen a number of weather balloon projects where people launch stuff to 100K or so and get it back. The rocket itself is probably FAR 101, so no particular waiver there. The rocket is only going to ~3000 feet (assuming all the motors light with the rocket vertical ) above launch altitude, so the total altitude shouldn't be crazy. Do weather balloons need an FAA waiver? If so, who would normally ask for them? Is there a ceiling that you can fly to with no waiver?

I'm not in any way saying that these guys will be successful, I'm just curious about the letter of the law.

davdue said:

From their description: The reasoning for so much power is because of the amount of mass on the rocket, plus we think its cool! The motors will be linked together in series instead of parallel to maximize success of all engines igniting at once.

This is more evidence they don't know what they are talking about. Motors linked in series to maximize success of all engines? Are they talking about the igniters? If so, only the first one will light unless they get lucky and the second igniter gets enough current to light while the first is lighting, most likely this will not happen.

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Actually connecting igniters in series is a valid strategy for clusters. All of the igniters pass the exact same current. Look up some of the massive clusters Boris Katan has flown.

Steve Shannon said:

Actually connecting igniters in series is a valid strategy for clusters. All of the igniters pass the exact same current. Look up some of the massive clusters Boris Katan has flown.

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Ok. Ohms law says that will happen. I was just thinking that only the first one would see the current long enough to burn. It must happen fast enough that they all ignite. I have never done any clusters. I thought it would be like Christmas lights that are in series. If one burns out they all go out.

Where's MClark? He's normally all over stuff like this.

davdue said:

Ok. Ohms law says that will happen. I was just thinking that only the first one would see the current long enough to burn. It must happen fast enough that they all ignite. I have never done any clusters. I thought it would be like Christmas lights that are in series. If one burns out they all go out.

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You’re correct that if one burns out the current in all of them drops to zero. Current has to go somewhere though, so as long as one in a series sees current, all in a series sees the same current. The first one in the series doesn’t necessarily heat up before the last. Heat transfer is much slower than electron flow.

Steve Shannon said:

You’re correct that if one burns out the current in all of them drops to zero. Current has to go somewhere though, so as long as one in a series sees current, all in a series sees the same current. The first one in the series doesn’t necessarily heat up before the last. Heat transfer is much slower than electron flow.

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iirc the ignition temp for the igniter pyrogen is below the temp at which the bridgewire burns through allowing the igniters to start burning well before the circuit is opened by a burned through bidgewire.

Steve Shannon said:

You’re correct that if one burns out the current in all of them drops to zero. ...

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Interestingly, for this question on the NAR L2 exam (Paraphrasing; Unless otherwise specified by the mfg., should clusters be wired in parallel or in series?) the correct answer is given as

jlabrasca said:

Interestingly, for this question on the NAR L2 exam (Paraphrasing; Unless otherwise specified by the mfg., should clusters be wired in parallel or in series?) the correct answer is given as

The answer is “[parallel]“. If the igniters are wired in series the first igniter to burn out opens the circuit preventing any other igniters from receiving electrical power. Parallel connections allow all of the igniters to independently receive electrical power. Some motor manufacturers may suggest series connections for electric match-based ignition methods; always follow manufacturer’s instructions. ​

View attachment 359675 ​

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Check some posts from jdermig on this issue. Being an electrical engineer I argued the same as above, but it is wrong in practice. If you look at companies that do this for a living, high explosives/dynamite or professional fireworks, none of them use parallel wiring for ematches. The ematches are designed to both ignite and melt (plasma state) the nichrome so that continuity is achieved long enough to fire many dozen in series.

Speaknoevil said:

Check some posts from jdermig on this issue. Being an electrical engineer I argued the same as above, but it is wrong in practice. If you look at companies that do this for a living, high explosives/dynamite or professional fireworks, none of them use parallel wiring for ematches. The ematches are designed to both ignite and melt (plasma state) the nichrome so that continuity is achieved long enough to fire many dozen in series.

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I am an electrical engineer too and agree that series wiring makes sense IF you do it correctly. I am sure that these professionals know the specs on every aspect of the explosives, wires and igniters they use. They measure and test everything to ensure that each and every igniter sees the same voltage and current. One igniter with a resistance value twice that of all the rest? Reject it and get another one. Test, measure, inspect, repeat. I doubt many people do the same with rockets and igniters; and I'm sure these Kickstarter guys won't do that. If you don't want to test and measure everything to the Nth degree then parallel wiring is the better bet.

Zeus-cat said:

I am an electrical engineer too and agree that series wiring makes sense IF you do it correctly. I am sure that these professionals know the specs on every aspect of the explosives, wires and igniters they use. They measure and test everything to ensure that each and every igniter sees the same voltage and current. One igniter with a resistance value twice that of all the rest? Reject it and get another one. Test, measure, inspect, repeat. I doubt many people do the same with rockets and igniters; and I'm sure these Kickstarter guys won't do that. If you don't want to test and measure everything to the Nth degree then parallel wiring is the better bet.

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Even if wiring igniters in parallel you should measure their resistance first for exactly the same reason, or risk them igniting their pyrogen at different times (or not).

Igniters and e-matches are both being mentioned, they are not the same thing. Igniters generally take more current and burn through, e-matches (supposedly) weld together and use less current. I never do a continuity check on either after firing so I can't confirm or deny that. My only experience with e-matches is ejection charges.

MikeyDSlagle said:

Igniters and e-matches are both being mentioned, they are not the same thing. Igniters generally take more current and burn through, e-matches (supposedly) weld together and use less current. I never do a continuity check on either after firing so I can't confirm or deny that. My only experience with e-matches is ejection charges.

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If you fly CTI you are using ematches (which in turn light the internal pellet) even though they call them ignitors.

They are different only in rocketry. In other professions, they are the same. We should call them what they are - “motor lighters” and “ejection initiators”. That will make it less confusing. The second by design must be low voltage. The first usually has added pyrogens no matter what voltage it requires.

MikeyDSlagle said:

Igniters and e-matches are both being mentioned, they are not the same thing. Igniters generally take more current and burn through, e-matches (supposedly) weld together and use less current. I never do a continuity check on either after firing so I can't confirm or deny that. My only experience with e-matches is ejection charges.

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If you look at their construction you will see that they are nearly identical electrically. Ematches have smaller nichrome wire, frequently wrapped around a miniature printed circuit board and then soldered to pads before being cut apart and then dipped in a small amount of electric match compound, which is a type of pyrogen.
Igniters are a single piece of nichrome wire connected between two copper leads and then coated with igniter compound. I don’t know the difference between the chemical compounds (or if the only difference is quantity), but my experience is that igniters burn longer.
It’s not highly unusual to have igniters and electric matches continue to pass current after use. The nichrome wire burns at a much higher temperature than the pyrogen. In rocketry, electric matches are more frequently fired using lower voltage devices, such as altimeters using 9 volt batteries so there’s less chance for them to burn out like a fuse. Igniters are almost always used with a 12 volt launch system which drives more current through them and thus stands a greater chance of burning through. Anything connected to a 12 volt launch system is more likely to burn out than that same device connected to a 9 volt altimeter.
If there is something special about the electric matches which causes them to retain continuity after use, I don’t understand what it is. I’ve heard the same thing said before. It may be just because of how they are used in series in fireworks and thus they see a lower voltage, resulting in lower current and less chance to burn through. My launch system shows the continuity of an igniter or ematch after use. When we launch CTI motors which use an electric match we don’t see anything unusual after firing them.

I am sure that this is well distributed in the community, but John Lyngdal published this test of model rocket igniters

https://www.apogeerockets.com/education/downloads/Q2G2_Igniter_Report.pdf

at the end there is some discussion of the series/parallel question.

The question on the NAR Exam is equivocal.

Scanning it just now, while there are questions about igniting clusters, it does not appear that TRA L2 exam addresses the particular question of a preferred wiring scheme.

I do really like this question from the TRA exam:


Speaking from a professional interest in exams as teaching tools, I congratulate the person who wrote this. The choices are great.

The TRA L2 test has at least two errors. We’ll be redoing the test hopefully soon.

Steve Shannon said:

The TRA L2 test has at least two errors. We’ll be redoing the test hopefully soon.

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Gee, I hope that the question I liked isn't one of the mistakes. Not only does the preferred answer require some imagination and a fairly sophisticated understanding of dynamics, the wrong answers are diagnostic.

Multiple choice exams are, in general, useless for assessment or for teaching. Its a little bit thrilling to see a well-exceuted question.

Its a whole-other discussion, but the NAR L2 test gave me a headache. It has all kinds of specific-knowledge questions about things that we should actively discourage fliers from committing to memory. IMO, and writing as a past ISO auditor.