Tim's stuff is so great. Easy to be jealous of, since being YouTuber seems easy, but to make quality content, it really can't be.
And then he's going around the moon, it's really mind blowing to see the success he's had. His interviews with Musk are a treasure trove as well, whatever you think of Musk.
> His interviews with Musk are a treasure trove as well, whatever you think of Musk.
My main take away from those interviews is just how knowledgable Tim is, he's able to engage in low level and in depth conversations about how these engines work. It's not just superficial high level knowledge from making videos, he is thinking himself how to optimise and improve these things, and leading that conversation. The passion for it is electric.
In another life Tim would have been an incredible engineer, but that value he brings as an educator is immeasurable. Thats how he has earnt his way to a space flight.
(They also show that the common argument that Elon doest know his stuff is wrong (at least for rockets), but I really don't what to derail this conversation into that.)
> Imagine if all journalists had this level of depth in all of the topic they covered? I don't think that's possible though.
It helps a lot that Youtube seems to have become the home of long form video. Not really something that fits into traditional media. But for the people that really want to dive deep into a topic, it's great that there are now often high quality creators that cater to those tastes.
Does not fit in traditional media indeed. When I was a kid/teen, Discovery Channel, at least in my native Netherlands, had some interesting content. I could also gobble up something like How it's Made all day.
Content like Tim's could definitely fit in there too.
YouTube enabled everyone to publish this type of content, for good and bad...
When I was younger I loved shows like Modern Marvels on History Channel that presented the engineering behind the various amazing everyday things that we take for granted in a format accessible to the layman.
It's depressing that good shows like that were killed off in favor of the "reality" TV and conspiracy/aliens/etc show junk food that took over Discovery and History from the mid-00s onward.
I agree. You need that intersection of interest, presentable qualities (listening, digesting,responding, speaking) and quest for accuracy. Hard to get those all in one person.
I don't get this sense at all. I've been watching his channel for a couple of years, and I've consistently found him to portray himself as a fan/enthusiast trying his best to understand and summarize complex information he doesn't have first-hand knowledge of. He's never pretended to be an engineer.
I think the value is in getting inspired to dig deeper when he shows you something interesting.
It's absolutely worth to go on a tangent here - Tim did a great job in explaining Elon (or showing him to the public in a probably not too filtered way).
Musk is a clown but I'll give him one thing: he cares about technology. That's something that very few modern CEO in big tech have and probably gives him the edge in making his project successful.
> Musk is a clown but I'll give him one thing: he cares about technology.
His hot takes on software / software architecture have been disappointing[1], and made me question the validity of his assertions in domains I have no expertise in (rocketry, computer vision and manufacturing).
1. Also, he wants to remain in charge of "Servers and Software" at Twitter even after (if?) He steps down as CEO.
I was thinking of pre-Twitter Musk. I'm not sure what game the clown is playing now or even if it's a game at all anymore. It's so bad that it's almost like a trash artistic performance. GG Allin billionaire.
Tim's stuff certainly has the information content nailed down better than most typical "science" youtubers, but he comes off as slightly overexcited at times, which brings up negative associations with typical misleading pop science rags for me.
To pile on the Tim Dodd praise, be sure to check out his music too (which is used in the videos). Solid stuff that reminds me of Tycho. So glad he got picked for the Dear Moon mission.
He, like most big Youtubers, probably have a large crew of people working with them. The article was written by Trevor Sesnic, the video was likely edited by others, I don't know if he did the graphics, but Tim still did a lot (and arguably did the most fun stuff). Smaller Youtubers need to do all of that, and from what I've heard editing is the absolute worst given how time consuming it is. Many Youtubers struggle with burnout centered around how time consuming editing becomes.
Tim's content is really great though, and he does a fantastic job of explaining complex topics in a welcoming way. Very similar to smartereveryday IMO, where it is just really engaging and informative content presented in a great way.
I support Tim on Patreon. He also utilizes a cadre of Patreon donors who provide commentary on early cuts of videos and even drafts of scripts. I personally have never understood why people would pay to do work for him, but they must get satisfaction from it, and the final product is better because of it.
From the about page:
> In 2019 the team grew from just Tim to a small army of incredible helpers who make this website amazing, the videos higher quality, and help foster a fun and positive online community.
So the 2017-2019 period where the channel took off was all done by him solo, apparently.
I'd also add this standard. Another amazing YouTuber is Veritasium. He went from [1] to [2]. The production quality is more than slightly improved, but the "spirit" remains identical. And I think that spirit is what drives success or failure. The production quality is just icing.
It’s pretty rough because those ‘you’re wrong’ videos are actually just as wrong as he was. The main issue is that these complicated topics are difficult to describe properly is a 20 min English video that has to be edited to be interesting.
How electricity propagates is really complicated topic involving 3D vector calculus, for the EM waves. Most people don’t do electronic circuits by evaluating the vector field, they use the model of electron flow and the elements model (capacitance, inductance, resistance, voltage etc).
Ultimately these models are difficult to understand and most people (including my lecturers) make mistakes explaining them.
The best you can get is stuff people have extensively peer reviewed.
So Feynman Lectures on Physics for example are hard to beat. Though you will want to check for the various errata, the fact it was taught by a world class expert and received a great deal of peer review after the fact is about as much as you can hope for on any subject.
Sorry but no. Our ‘models’ of the universe will never be 100% correct.
If you’d like a 100% ‘correct’ explanation of the maxwells ‘laws’ of electrodynamics I refer to a sibling comment regarding the Feynman lectures. lectures.
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.
> and from what I've heard editing is the absolute worst given how time consuming it is. Many Youtubers struggle with burnout centered around how time consuming editing becomes.
This totally depends. If you're an editor, there is a great sense of pride of turning the pile of content handed to you into something cohesive and compelling is quite a skill. Some people just don't like it, and that's fine. I don't like building UIs, but sometimes I just gotta do it. It makes me appreciate those that do the task I don't like that much more. walk a mile in another person's shoes so to speak.
Just like coding, you can get in the zone with an edit and things just start flowing. It usually comes after multiple sessions of sitting there scrubbing through the content thinking to yourself "wtf do I do with this?" when inspiration finally hits. You just start remembering a shot from this clip that flows nicely with this next clip and it suddenly "makes sense". It gets really spooky when you then try to find some audio clip like music and drop it in and it pretty much lines right up. That's for unscripted stuff that's just kind of produced like film is cheap kind of shooting.
When you have scripted stuff that every shot has been logged and tagged where there's variations on delivery or any other slight thing that makes it appear to be the same thing over and over again comes with its own challenges and rewards. Sometimes, there's a perfect delivery but something doesn't line up continuity wise, so it looks like it can't be used. Then, you scrub some other angle or reverse or cutaway and hide the edit so that you can use that perfect delivery or borrow that perfect reaction that otherwise might not have made sense.
There's a reason it's an art. Not liking it doesn't mean you're wrong for not liking it personally, but it doesn't make it the absolute worst.
> and from what I've heard editing is the absolute worst given how time consuming it is.
It can be, but as with many things it comes down to learning the techniques as well as the tools. You can learn how to edit quickly and effectively with a couple of simple rules, but the most important is "don't worry too much about throwing stuff away".
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'm very surprised HN loves this guy.
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 pro, not a con. Rocket scientists' core competency is designing rockets, not teaching, and subject matter experts often make poor teachers. If this were a case of some kind of hucksterism, where he's an ignorant layperson making shit up and passing it off as true in his educational content, I'd say there was some concern, but while he's apparently said some dumb shit on Twitter, it doesn't seem like you or most other commenters are pointing to anything factually inaccurate _in this article_, nor indeed do people tend to on his researched, long-form stuff generally (vs. some off-the-cuff tweet). In that sense, it seems like this content is as good a place as any for laypeople to learn about this topic, that it doesn't obviously suffer from his lack of formal training, and maybe benefits if it means his better able to translate technical content to non-technical audiences.
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)
I often do too! But I certainly also had some professors in college who were frankly just really bad at conveying their expertise in a way that was accessible to people who were not also already experts. Some SMEs happen to have good communication skills and can be really fun to talk to, but the systems that produce experts don't, in my experience, select for these attributes, so whether or not you get them is pretty luck-of-the-draw.
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
I decided people are just having fun and it's nothing serious just water cooler chat and distraction before going back to work.
Subject: Something quantum mechanics.
Comment: "I'm not a physicist, but I think..." -- What do you think follows after such an opening? Exactly. It's fine though. I decided that the users decided that the site is at least 80% distraction and entertainment, and it still does so at a higher level than most others, so it's all good I think.
I'm always surprised how quickly a thread than isn't software related nose-dives.
Me and my colleagues joke about the weekly HN thread of people misunderstanding some physics article, or posing a nonsensical solution to a "trivial issue within physics".
Could you give me an example of his 'arrogance'? I've been watching his content for some time, and I'd say he's always been very upfront and transparent about being an enthusiast/fanboy and not an engineer. His concept is to be an audience insert and ask the stuff his non-professional audience would ask, as a sort of avatar. I would expect no more expertise from him than from myself.
If the people he interviews are humoring or correcting him, that's exactly what I would expect and is part of the value of the content really. He's giving them a platform and enthusiastic laymen a chance to ask dumb questions.
I can't find the tweet where he suggests to Elon how to design the sides of the rocket. Elon just shuts it down. I've never once heard EDA push back on anything Elon says even though Elon can say some outlandish things every now and then. That blind fanboyism is annoying.
While not public, my friend was his liaison at Blue origin when he toured. He was extremely rude to the team at Blue. It actually surprised the media team how condescending he was.
In my personal experience, most people at my company don't like EDA. On the other hand they love Scott Manley. It's not about what you know it's about what kind of person you are.
No, he's not an engineer and he cannot build anything, he has no special insights or novel ideas. He is an educator that popularizes niche and inaccessible knowledge to a large audience and that large audience really appreciates his efforts. His work in popularizing space tech is a net benefit to your industry and thus your company.
Not sure, I have not encountered this author before, but frequently in many fields a fan / enthusiast perspective is different than professional / expert perspective.
He's incredibly annoying, but he knows his shit. He's like a crypto influencer who also happens to be a brilliant engineer. I watch his content because it's insanely informative, even though he reminds me of every con artist I've ever met.
That's a perfect description of the feeling I get when watching him. Something just feels slightly off enough that I fully expect some skeletons to come out of his closet at some point like with the vast majority of crypto influencers.
I think you need to compare HN to just about any other open forum. HN users seem gracious, knowledgeable and logical compared to the rest of the Internet. Yes, we do need HN equivalents in other fields, notably Physics, Life Sciences, and Rocketry.
I forget exactly what he suggested but I remember is being like kind of dumb. Elon was humoring him. This guy is absolutely not a rocket scientist. He's not even an engineer.
If I recall, Musk was explaining that on the Starship booster they had recently begun to use directed venting of ullage gases for control authority to save a seperate hot or cold gas thruster system and Dodd asked if this also applies to the ship. Musk then went "now that you mention it, we should look into that". During a visit a year or so later he then confirmed they had begun doing it on the ship too and that it had occurred to him as he was explaining it to Dodd.
It's of course unlikely that the engineering team wasn't already considering this, but it's also not like Dodd was suggesting anything, he was just asking a follow-up question. The way the conversations played out was Musk remembering to ask someone about it later to check the status of the plan or drive a decision, and later recalling that conversation when Dodd came by again.
In my (lay) opinion, this is still evidence that he at least has some idea of what he's talking about and not all his suggestions to Elon are "pants on head dumb". I was never under the impression he actually suggested something the team had never thought of.
You can't be in the space industry or even a tangentially related aerospace sector and not be a fan of SpaceX. It's continuously been 10 years ahead of the rest of the industry. The entire industry did nothing but tread water for 50 years after Apollo despite massive technology and manufacturing advances. The space shuttle was one giant deadly 30 year step backwards.
SpaceX has an effective monopoly on low cost launches for a reason. The closest company to it in terms of low cost capability is Blue Origin which hasn't even been to orbit yet. No one but ULA or Roscosmos is close in terms of reliable either. The Space Industry would still be launching single use overpriced rockets to LEO without SpaceX revolutionizing it.
Regardless of you think of him and his 'dumb' ideas, with 1.4 million subscribers he will probably inspire more people than work at your 'small space company' to become real rocket scientists themselves. I wouldn't be surprised if he does more for the future of space industry than most of those who currently work in it individually do.
With that said, if you find him irritating, then you find him irritating. Hard to argue with that.
He doesn't represent himself as one either. Between he and Scott Manley and others there are a lot of kids out there who are pumped about space in ways that I never felt as a kid. Is it wrong to be enthusiastic about something that is not one's own life-work, to be exited about anything headed pointy-end-up, flamey-end-down? Look at the mission statement:
Everyday Astronaut’s mission is to bring space down to Earth for everyday people. To celebrate and lift up those who are helping humanity explore the world we live on and our place amongst the stars. We believe the best way to get people excited about space exploration is through education. By breaking down complex topics, it helps give some perspective and insight into the decisions made every day through the industry. We help remove the barriers of intimidating subject matter to help foster an excited public to cheer on those who are pushing the boundaries and help inspire future generations. The point is, rocket science is awesome, and you don’t need to be a rocket scientist to be excited.
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.
You can watch the whole thing from the very genesis of the turbopump powered liquid fueled rocket. The British did a very thorough documentation project on the German A4 / V2 rocket after WW2 and it's all accessible to the public.
In particular, the pyrotechnic igniter that is mentioned in the article as still in use by the Russians was copied directly from there. Here's a direct link to the spot in the video where it is assembled for use.
Space shuttle main engines (RS-25) had a very complicated startup process, deviations from this could cause all sorts of different things to fail catastrophically.
I feel like this is a subtle jab pretty much nobody outside of serious aerospace enthusiasts is going to get. For those who don't know, right now there's sort of a competition for the 'next big thing' in rockets. Congress/Boeing/Lockheed have been working on the SLS or Space Launch System since 2011. It was expected to launch in 2016. It had its first trial launch in 2022, and is tens of billions of dollars over budget.
It's also expected to cost billions of dollars per launch. Its more common nickname is the Senate Launch System, since it's largely just a really big pork project. It's already not especially competitive against the Falcon Heavy, and is being built at the same time SpaceX Starship is also being built. That project began in 2017, is being completely privately funded, and expected to revolutionize spaceflight once again - with costs potentially as low as $1 million per launch.
Anyhow, the SLS is reusing a bunch of old technology from the Space Shuttle. This includes the RS-25 engines...
The SLS is mediocre but there are a few things to keep in mind:
1) NASA needs to keep in house rocketry expertise and the US government cannot rely on private companies 100% just for like NatSec reasons.
2) If NASA doesn't structure programs as pork barrel projects that make it difficult for small time senators to kill, they will constantly be nickle and dimed and have their budget slashed until their entire job is just to make memorabilia to sell.
3) Elon is not trustworthy. Our country should not rely on him. Starship hasn't launched yet, while SLS has now. I am excited for starship to launch, hopefully soon, but it's still not a functional rocket.
1) The US government does rely on private companies 100%, SLS is built by Boeing, a private company. Being a private American company has very little issue when it comes to national security, just means you have them meet various requirements (eg only allowing US persons to work there and security clearance requirements).
2) Unfortunate that our system is so corrupt, but agreed. Fortunately there is also the Artemis approach of tying in so many international partners that it becomes a matter of national prestige.
3) I suggest looking up "The Falcon 9 Heavy may some day come about. It's on the drawing board right now. SLS is real.".
> NASA needs to keep in house rocketry expertise and the US government cannot rely on private companies 100% just for like NatSec reasons
Do they? Most national security work in space is under NRO and USSF, not NASA; neither of them build their own rockets but instead rely on commercial vendors.
The Army doesn't build its own rifles or tanks, the Air Force doesn't build their own fighters and bombers, and the Navy doesn't build their own ships. Operations is different from designing equipment; the only time it makes sense for the same organization to do both is when that organization is so far out on the cutting edge of innovation that they have to do both. (Ironically it's SpaceX that is in this position with regard to Starlink.)
NASA was in this position during the Apollo era. They aren't in this position anymore. It should have been a hint as early as the Shuttle era when they went and designed the Shuttle as (among other things) a satellite launch platform, only for commercial vendors to provide unmanned rockets as satellite launch platforms instead. As it stands now, NASA carries out a lot of scientific missions that don't have an immediate commercial application, which is a good thing for them to do but doesn't require them to design their own rockets.
Furthermore, it's not even fair to describe SLS as "in-house", since it's built by Boeing and Boeing is bidding the system for their own commercial contracts now. At that point it's just a question of which private company the government can rely on.
All the imperial units in this PDF hurt my head. I'm an American, so I'm used to them, but seeing them in the context of precision aerospace hardware is so jarring. As a student it seemed like math re: chemistry and physics was so much easier (read: less error-prone) with metric units than with imperial. Mars Climate Orbiter indeed.
The biggest lessons learned on the Mars Climate Orbiter wasn't exactly that everything should be metric. It was the unit conversion is dangerous and needs to be handled very carefully. Just saying everything will be metric doesn't avoid unit conversion. You might have one thing measuring fuel burn rate in grams/second and another in kg/second. That conversion can still lead to issues if not handled correctly. In the context of the space shuttle it was all designed in imperial units starting in the 70s so it would be very risky to convert everything to metric.
- There is only one unit for each dimension. In your example, "grams/second" would not be a valid unit; SI only has kilograms/second (yes, it's annoying that the unit of mass has a name beginning "kilo" :( )
- The conversion factor between different dimensions is exactly 1 (by definition). In your example, the rate R is related to mass M and time T via M = TR (i.e. kilograms = seconds × kilograms/second). There are no conversion factors, since the unit of rate is derived from the units of time and mass (unlike, say, measuring energy as calories OR pound-feet OR coulomb-volts OR ounce-miles OR slug-acres-per-squared-hour OR ...)
When designing new systems it is best to clearly define the expected units for everything clearly at the start. SI units are great but sometimes they are not great for the specific use case. When measuring high power systems like power plants or EVs kW/MW/GW are a more appropriate unit versus Watts. In embedded systems you have limited bandwidth having to have large variables just to store values in SI units is a waste versus using an appropriately scaled unit and saving bandwidth.
Overall the conversion of the unit isn't the root of the issue. Clearly defining the data types and units of everything is the key issue. This makes sure any conversion is done when necessary and allows people to design systems so that they can avoid conversion if possible.
> SI units are great but sometimes they are not great for the specific use case. When measuring high power systems like power plants or EVs kW/MW/GW are a more appropriate unit versus Watts.
A non-SI example would be e.g. kilowatthours (kWH); since 'hour' is not an SI unit. The SI equivalent would be 3.6 MegaJoules.
> In embedded systems you have limited bandwidth having to have large variables just to store values in SI units is a waste versus using an appropriately scaled unit and saving bandwidth.
- Floats are designed to be scaled, by adjusting their exponents. In the happy case, our algorithms don't care; so why not stick with standard units? In the unhappy case (imprecision, numeric instability) we may need a mixture of entirely bespoke representations, even within a single algorithm. Ideally we'd still use standard units at the "boundaries".
INT_MAX is usually 2147483648, which means a "power" figure in Watt can handle anything from a laptop CPU to a Chernobyl power plant. FLT_MAX and _MIN are e+38 and e-38 so couple digits over and under(within 32bit precision).
Have you actually had that kind of unit confusion in metric, or inferring from your experience with Imperial system? It kind of just seems to reinforce suggestion that Imperial system having bunch of redundant or weird units IS the problem.
(for your defense: try [METRIC_UNIT]/h and /s. e.g. km/h often used for display in slow vehicles and m/s used for calculation motions of fast objects are kind of confusing.)
INT_MAX is assuming every variable is using a 32 bit integer which is not always the case. In my experience with flight control systems controls systems were focused on using the smallest variable necessary for a given variable. We had many variables that were only 8 or 16 bits. The processing overhead wasn't really the driving factor for smaller variables it was typically interface bandwidth which can be very limited while maintaining required safety margins on aircraft.
We had a pretty massive ICD that defined every message going in between sub systems down to the bit level which is what was necessary to avoid unit confusion when dealing with system creates by sub contractors and such. Your example of velocity is pretty common thing that you would have to reference the ICD for. Is this velocity signal in KM/h or m/s, as well as MPH, fps, and Mach number.
Sure you could say all velocities need to be in m/s, but then if all your control laws for higher speeds which have been fined tuned through 10s of years of work utilize Mach Number in the calculations is it safer to update all the controls laws or just do a conversion?
> Sure you could say all velocities need to be in m/s, but if all your control laws for higher speeds which have been fined tuned through 10s of years of work utilize Mach Number in the calculations is it safer to update all the controls laws or just do a conversion?
Mach Number is a dimensionless ratio; I don't understand what that could have to do with velocity units? (Any units used in its calculation have cancelled-out by that point)
> You might have one thing measuring fuel burn rate in grams/second and another in kg/second.
One of my jobs is reporting on packaging weights[1] in the UK and it's not uncommon to have this problem when I request data.
For example we request in Kgs, but one manufacturer sent back the report table of numbers in grams. That meant the thin plastic sleeve a tube of paper coffee cups comes in was reported at 30Kgs rather than 30g.
These components are all taxed / levied at various stages in the supply chain so being out by a factor of 1,000 can make a significant difference - we sanity check all our data, but a surprising number of people don't. It's not life threatening, but expensive!
[1] It's for the UK packaging waste regulations and packaging taxes. For a case of paper coffee cups we report on the weight and materials of every component such as the cardboard outer box, labels, parcel tape, inner sleeve bags, paper in the cups and the plastic lining in the cups.
If I have data going out on a data bus in grams/second, but someone reading that data in a different sub system reads it and thinks it is kilograms/second because that is the default unit they use then you have an issue. The actual conversion of the bits isn't the issue it is that certain systems might use different units internally and making sure those conversions are done correctly. It is much more an engineering design/human interaction issue than a computation issue.
Pretty sure GP was making a sarcastic comment referencing how floating point is notorious for subtle rounding issues when handling values that have an exact representation in base 10 but a repeating pattern in binary.
Yes, I understood that. However repeated conversions can lead to rounding errors such as catastrophic cancellation. This is even more esoteric than “grams here kilograms there” and thus easier to fall prey to. Depending on how precise your measurements are you could easily drop significant digits or add random noise, especially if you do large scale changes.
Yeah we tended to utilize fixed point for many of our variables and documented the precision for each one. Then an analysis was done verifying that we were maintaining precision through the calculations from input from a sensor to output.
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.
I mean, sure, converting grams to kilograms is easier (for a human) than converting ounces to pounds, but how often do we have to do that in our heads? Computers, on the other hand, do not care (and they "prefer" the binary system anyway).
Converting grams to kilograms not so much, but mm to m, mL to L, even g to mL and L to kg (of water) — all the time, and of course in our heads — it's so easy you barely need to think about it.
I don't even consider those to be "conversions" at all; in the same way that "two dozen metres" and "twenty four metres" and are both just some number of metres (not a conversion from a separate "dozen-metre" unit).
Technically, the SI standard does consider millimetres, centimentres, kilometres, etc. to be separate ("derived") units from the base unit of "metre". That matters when we have multiple interacting multiples, e.g. "one cubic centimetre" is not the same as "one centi cubic metre"; but of course, that's avoided if we stick to base units like cubic metre. (see http://www.chriswarbo.net/projects/units/improving_our_units... )
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-rocketry.net/
Others focus on flight controllers, GPS trackers, and other electronics. https://altusmetrum.org/ (i think one of the two owners of altusmetrum is a pretty famous Debian Linux guy from back in the day)
There's also "hybrid" engines that use a solid fuel and a liquid oxidizer ( nitrous oxide ). Ex, this guy is probably the most well known in the hybrids side of the hobby https://contrailrockets.com/
Finally, there's the halfcat guys https://www.halfcatrocketry.com/ who do amateur liquid bi-prop engines in an approachable way. I've working on a design of my own based on their designs and plan to do a static fire in the Fall and hopefully a flight before end of year. The downside with liquid engines in the hobby is governing bodies Tripoli and NAR don't allow these engines at sanctioned launches. You either have to launch privately (including coordinating/paperwork with the FAA on your own ) or at FAR https://friendsofamateurrocketry.org/
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) which feed a total of 20 main and 12 steering combustion chambers across the center core and 4 boosters, so they need to light 32 of them for each launch.
Multiple combustion chambers per engine was their way to mitigate combustion instability; Rocketdyne blew up a lot of engines before they figured out a different approach (involving baffles on the injector plate) in the Saturn V's F1 engine.
You probably already know of him, but you should check out BPS Space on youtube if you enjoy long-form video edutainment. Much like Tim Dodd, Joe makes videos full of detail and information about topics he is clearly passionate about. In the case of BPS Space that is pushing the limits of amateur rocketry in a uniquely hacker/programmer friendly manor.
It was super fun to bring together lots of different disciplines and skills. 3D printing, software, soldering, circuit design, simulation etc.
Ultimately, I got so obsessed with it I got burned out and had to take a break for a bit but came back fresh and finished it. Did a few flights over the year with more and more interesting things culminating in a dual stage flight. I've still got the rocket ready to go anytime. Just gotta wait for the weather to clear up.
Tangential but related: "Toxic Propellant Hazards"[1] a video made in the mid/late 60s and published by the US National Archives Youtube channel. In addition to having some great information about hypergolic propellants, and having some interesting footage showing what they're like to use, it also has that mid-century production quality, the kind that the Fallout games love to simultaneously lampoon and pay homage to
“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.”
Definitely among one of the great pieces he has produced. Highly informative and educational. He really finds the right tone and this long piece never gets boring for a second. Also from a production perspective his animated engine charts are top and visualise the point he is making.
BTW his interviews with Elon Musk at Starbase are also a must see (some clips included in this video as well). You really start to see and understand how Musk works - and it's not as bad as media is trying to make him. His engineering principles are really interesting and can be applied to many scenarios. It's this level of abstraction that makes the difference and gives him a competitive edge.
Yeah, I think atoms are just so cool. After almost two decades of many different kinds of software, it all starts to looks the same and kinda boring. Even LLMs, which are super exciting, can barely hold my interested.
All my startup and side-project ideas are now robot or machine based. Feels like the combo of LLMs (or rather large multi-modal models) and cheap robots will yield tons of interesting results over the next decade.
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).
They used to use what were basically shotgun shells with no pellets to start airplane engines -- it was called a Coffman engine starter (it was actually used as a plot device in the movie Flight of the Phoenix).
Even today it can be a bear to start the engine of a small piston-powered aircraft. The vast majority of engines used in these aircraft haven't changed very much in the last 70 years.
I've personally dealt with the engine in a Cirrus SR-22 just refusing to start. It was at operating temp on a hot day. We flew in to an airport with the plan being to stop just long enough to fill the fuel tanks and drain our own tanks. The engine was off for about 15 minutes when we went to restart.
We experienced vapor lock, ended up flooding the cylinders with fuel, and at that point we just had to wait. After about 10 minutes we were able to get the engine started. There are no electronics controlling this engine, everything is controlled by the pilot.
FADEC (Full-Authority Digital Engine Control) has slowly started making its way into the small piston market over the last decade, but even with that, it's still controlling engines that are fundamentally the same designs flying in the 50s.
Yes, early cars had to be started with a crank handle that stuck out of the front of the grill, similar to how early propeller engines had to be hand-spun to get going. Apparently if you didn't crank it quite hard enough the handle could snap back at you rather violently, one of my great-grandmothers had her arm broken this way.
> the handle could snap back at you rather violently
If it backfired. I got thrown over a Studebaker that way when I was like 8; I wasn't big enough to turn the handle by hand so I was jumping on it. It usually worked tho.
With the piston engines they had to be turned over by hand first to let the oil drain out of the cylinders before starting them by pulling on the propeller.
Check out a video on how to start a model T. It was a two man job: one on the inside fiddling with spark timing, the other on the outside cranking it over. Often you also need a bit of priming (aka choke).
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.
This is great. My rocket starting experiences extend to hitting space in KSP and mashing the red button on an Estes launcher. To be fair in KSP they often wiggle to death on the pad and I’ve spent more time with bored 6 year olds wandering off as I figure out why the Estes motor didn’t ignite, but that’s nothing compared to this.
Tim's stuff is so great. Easy to be jealous of, since being YouTuber seems easy, but to make quality content, it really can't be.
And then he's going around the moon, it's really mind blowing to see the success he's had. His interviews with Musk are a treasure trove as well, whatever you think of Musk.