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How to start a rocket engine

everydayastronaut.com

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Re: How to start a rocket engine

#91

Post by kevviiinn »

LargeTomato wrote: post #50

I'm surprised at the amount of people who enjoy EDA. I find him very irritating. Most people at my small space company find him extremely irritating. He is not a rocket scientist. He parrots silly buzzwords like "biomimickry" like a fanboy, not an engineer. He suggests things to Elon for how to do rockets that are just pants-on-head dumb. His blind fanboyism and arrogance irritate so many people who work in space. I'…

HN is mostly software devs, as someone in the bio sciences whenever I see comments about my field they're nearly always wrong unless another person in the field is commenting which isn't very often. It seems like software devs like to think they understand things when it's just barely surface level knowledge, I don't know why

Re: How to start a rocket engine

#92

Post by WalterBright »

bewaretheirs wrote: post #75
chasd00 wrote: post #28

I think there was a russian engine that literally had 2x4's on fire stuck in the combustion chamber in place of torch ignitors or TEAB. If anyone's interested the experimental high-power rocketry hobby is pretty fun, there's a lot to learn and hack on. A lot of people focus on propulsion and formulating, profiling, and flying various solid fuels they develop themselves. This guy is highly regarded https://www.nakka-r…

Yes, the Soyuz (the workhorse Soviet/Russian launcher for crew, smaller satellites, and space station cargo) is ignited that way (and it's mentioned at the Everyday Astronaut page linked above, just under the "Ignition on the Ground" heading). There are pyros on top of the wood, so it's really just a really large electrically ignited match. IIRC the Soyuz family have five ground-start engines (propellant pump sets) w…

The V2 used baffles, too.

Re: How to start a rocket engine

#93

Post by Retric »

Diederich wrote: post #85
Retric wrote: post #26

Earlier quoted context omitted.

Veritasium videos are often subtly misleading which really annoys me. It’s great for views, but terrible for science education.

Is one example his recent set of videos about how quickly electrical energy travels travels?

Yea, like “Darth Vader killed your father” they are true from a specific viewpoint, but people walk away misunderstanding what’s being described.

A more clear approach would be to say what we mean by electricity is the net flow of energy even if no electrons move from A to B, but that’s not going to get the same number of clicks.

Re: How to start a rocket engine

#94

Post by JshWright »

peterfirefly wrote: post #60
LargeTomato wrote: post #49

Earlier quoted context omitted.

To be honest he's regurgitating a lot of information. He has large gaps in his knowledge but presents himself as extremely knowledgeable. Understanding a rocket engine as a layman is easier than understanding a diesel engine. EDA acts like he's a genius but he is not. I work in space. Some of my coworkers have met EDA. He is insufferable and extremely arrogant. A very difficult person to be around.

> He has large gaps in his knowledge Yes. > but presents himself as extremely knowledgeable. No.

Perhaps he has gotten better at that in recent years. I got put off his early content for the very that very reason and haven't bothered to go back.

Re: How to start a rocket engine

#95

Post by Diederich »

oh_sigh wrote: post #54
LargeTomato wrote: post #50

I'm surprised at the amount of people who enjoy EDA. I find him very irritating. Most people at my small space company find him extremely irritating. He is not a rocket scientist. He parrots silly buzzwords like "biomimickry" like a fanboy, not an engineer. He suggests things to Elon for how to do rockets that are just pants-on-head dumb. His blind fanboyism and arrogance irritate so many people who work in space. I'…

His audience is fanboys, not aerospace engineers. So it makes perfect sense. He may be a fanboy but that fanboyism got him a trip to the moon.

> His audience is fanboys

SpaceX fans?

Re: How to start a rocket engine

#96

Post by sophacles »

apendleton wrote: post #74
LargeTomato wrote: post #50

I'm surprised at the amount of people who enjoy EDA. I find him very irritating. Most people at my small space company find him extremely irritating. He is not a rocket scientist. He parrots silly buzzwords like "biomimickry" like a fanboy, not an engineer. He suggests things to Elon for how to do rockets that are just pants-on-head dumb. His blind fanboyism and arrogance irritate so many people who work in space. I'…

With respect, you and your company of people who are already subject matter experts are not his audience; his audience is people who are not experts and want to learn about this subject matter. Most people on HN are also not subject matter experts with respect to rockets, so in that respect, are probably much closer to his target audience on average than you are. > He is not a rocket scientist. That might well be a p…

Also, SMEs say dumb things all the time. I know I have in my area of expertise. Not so much in "official capacity", sure - I try to make sure any presentations or blog posts or whatever are accurate. But random ideas I have, or initial reactions to some new tech - sure I've shared my really bad ideas.

Frankly if there was a youtuber out there making high quality, good faith attempts at presenting weird networking stuff - I'd love it and probably link everyone that ever expressed mild interest to that stuff. The folks that make explainer videos well are far better than me at getting the important concepts across to neophytes, and then I can help them understand more if they are still curious. (also - if this exists and I just never came across it please link :D)

Re: How to start a rocket engine

#97

Post by fnordpiglet »

sbradford26 wrote: post #88
fnordpiglet wrote: post #86

Earlier quoted context omitted.

The problem is almost nothing today accelerates fixed point and everything supports floating point accelerations, which will speed up your ability to calculate the wrong number by many orders of magnitude.

Yeah that makes sense. In aerospace they will fall on the side of accuracy even at the expense of speed. But they also tend to utilize FPGAs that can be designed to handle fixed point calculations quickly but with that comes a lot of cost and specialty hardware.

Another place it makes issues is financial modeling, particularly for complex derivatives where the model might be extremely complex and small errors can accumulate into meaningful errors in risk calculations. Fixed point is sometimes used in finance but performance is also a real concern. There’s a lot you can do to reduce fp errors if your numerical libraries are carefully constructed. But it has often made me wonder why there aren’t processor lines with high performance fixed point since the math is extremely easy - even by just shifting the mantissa and working in integer space then shifting it back.

Re: How to start a rocket engine

#98

Post by bryanlarsen »

ofrzeta wrote: post #87

Related: John D. Clark "Ignition!: An Informal History of Liquid Rocket Propellants"

“It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.”

Re: How to start a rocket engine

#99

Post by geocrasher »

LargeTomato wrote: post #50

I'm surprised at the amount of people who enjoy EDA. I find him very irritating. Most people at my small space company find him extremely irritating. He is not a rocket scientist. He parrots silly buzzwords like "biomimickry" like a fanboy, not an engineer. He suggests things to Elon for how to do rockets that are just pants-on-head dumb. His blind fanboyism and arrogance irritate so many people who work in space. I'…

His fanboy-energy is too strong, cannot stand him. And I don't even work in space. But I do work for a company called Rocket, so that's something I guess.

Re: How to start a rocket engine

#100

Post by bryanlarsen »

jackmott42 wrote: post #20
Koshkin wrote: post #16

Starting the engine(s) even in a propeller-driven airplane used to be a big deal, too. Hell, I'm sure that even starting a car engine back in the day was a much more complex affair (than simply pushing a button like it is today).

Those things really are fundamentally easier, which is why it became routine and something every day people could operate day in day out pretty quickly. Rocket engines are still very hard to do 70 years later.

Starting a modern car engine is not easy. They've got high compression ratios and are other wise tuned for high performance and fuel economy making a sustained ignition difficult. It's the computers and other timing components that make it seem easy and everyday.
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