Built a bespoke loyalty points system for a chain of gas stations back in 2020. Thought at first it would be a one time deliverable and then I could move on with my life. Cut to today and I'm trying to launch it into it's own platform.
Nothing much to show other than one client, but I'm on the cusp of charging them monthly vs getting paid by the hour.
I'm accustomed to seeing large plumes of chemicals coming out the other end in my minds eye when I think about rocket launches. This looks "clean" coming out the exhaust.
Why is that? Is it due to the nature of chemicals it uses?
Soot means carbon-rich fuel, like RP1, and a very fuel-rich mix. Most launches I ever saw had basically zero soot, and a clean exhaust of a well-balanced fuel / oxidizer mix.
Military rockets, and solid-fuel boosters like the kind the Shuttles used to use, indeed produce very visible exhaust, because they use heavy fuels, and sometimes heavier oxidizers, like nitric acid. This is because they need to be in the fueled state for a long time, ready to launch in seconds; this excludes more efficient but finicky cryogenic fuels used by large commercial rockets.
The large plumes that you usually see the first few seconds when a rocket is blasting off a launch pad are mostly water vapor. The launch pad would be destroyed by the exhaust were it not cooled during the launch by large amounts of water, which gets evaporated instead of the concrete.
Several reasons. It's filmed in daylight, so any flame or exhaust will be less visible. The rocket engine is much smaller than anything that would go on an orbital booster, so there's less exhaust than what'd you see for an orbital launch. Also it's looks like it's a hydrolox rocket (using liquid hydrogen and oxygen as fuel), which has the least visible flame. The combustion product is almost entirely water vapor. Methalox (methane + liquid oxygen) is the next cleanest, which emits water, CO2, and a little bit of soot. Kerolox (RP-1 and oxygen) is the most common propellant used today, and it emits a significant amount of soot.
Solid boosters put out the most visible exhaust, as burning APCP[1] emits solid particles of metal oxides. Also some rockets (mostly Russian, Chinese, and Indian) use unsymmetrical dimethylhydrazine + dinitrogen tetroxide, which emits a reddish-orange exhaust. Both compounds are toxic, as is the exhaust.
I doubt it's hydrogen, because the color looks off (blue, rather than pink), and because it'd be a poor fit for a small R&D project. They're not optimizing for performance-at-all-costs on this.
Ethanol/oxygen is my guess. Blue, and also very little soot.
Probably methalox I think. It's the trendy prop mix most reusable programs are settling on because it doesn't coke up engines like kerosene and is easier to model in computers, and doesn't cause metallurgical problems like hydrogen while being much more dense. Alcohol isn't impossible but seems unlikely to me because that's not what you'd want for the full scale rocket they're presumably working towards.
Hydrogen engines aren't always pink. The exhaust color depends on the ratio of oxidizer to fuel. The Space Shuttle's main engines were hydrolox, but their exhaust had almost no pink/red.
It's hard to say for sure, but I lean towards Honda's rocket using hydrogen. Honda has experience with it. They use hydrogen in their fuel cell vehicles, and their press release from 2021 mentions using hydrogen for rockets.[1]
I'm pretty sure both fuel and oxidizer are cryogenic, because when the rocket lands it vents from several areas (most likely separate tanks). That would rule out ethanol or methanol as the fuel.
I don't see any secondary exhaust from a gas generator, and staged combustion would be something to brag about (and much higher thrust), so my guess is that it's an expander cycle. Expander cycle engines require a fuel that boils easily, so it would have to be fueled by propane, methane, or hydrogen. I don't think it's propane, as the only propane/lox rocket I've seen has orange exhaust.[2] If Honda poached some engineers from Mitsubishi, I could see them going with a hydrolox expander cycle, as that's what the H family of rockets use.
The only thing that doesn't line up with hydrogen is the low thrust given the propellant consumption. Based on the claimed wet/dry mass (1,312kg/900kg), they used at most 412kg of propellant. Flight duration was 56.6 seconds, so that's an average of 7.28kg of propellant per second. If the stated wet/dry mass is correct and the rocket used up all of its fuel, then the rocket's thrust was around 13kN at the start and around 7kN near the end. Let's say it averaged 10kN. Force equals mass flow rate times exhaust velocity. So 10kN divided by 7.28kg/sec is 1.374 km/s. Divide by standard Earth gravity and you get 140 seconds, which is pathetic for a rocket. It could be that they only used a small fraction of the available propellant, or they had a poor nozzle design, or the engine was throttled very low and was therefore less efficient. If we assume the test flight only used 40% of the available propellant, then we'd get a flow rate of 2.9kg/sec and a specific impulse of 352 seconds. But that sort of assumption can be used to come up with any Isp.
Still, I think it's using either hydrogen or methane as fuel. Nothing else fits with the video.
It could simply be pressure-fed. No turbopump at all—just a helium tank.
You have a preference for assuming sophistication, but this is a one-off inexpensive test article with trivial performance needs. My guess is that they'd made the simplest engineering choices possible at every turn.
Most civilian rockets have solid strap-on boosters(actual technical term) that emit the signature thick white smokes, as well as leave contrails at high speeds. Neither would be visible for non-solid rockets at low speeds.
I'm reading through the book the blog mentions right now and building a small LLM. I'm only on chapter 2, but so far it's helped clarify a lot of things about LLMs and break it down into small steps. Highly recommend Building a large language model from scratch
Born Guyanese, but only lived there until I was 3, then we moved to St. Lucia. Have lots of memories from visiting over summers and Christmas multiple times when I was a kid.
Mostly consider myself Lucian and I feel like I've assimilated into the American tech population. My history now is just a interesting fun fact. Don't meet too many people from the Caribbean in general in tech circles, so it's always fun to get a reminder that they're out there.
AI is definitely a big part of it. When I would search Google with a technical question and land on StackOverflow I was looking for an answer. Sometimes you get a post which is similar, but not quite right, or the answers are only 95% of answering your actual questions.
AI of course just answers it. I can ask it follow ups, I can give it loose code and it just gets it. My grammar can be riddled with spelling errors and it still gets it. I can go back and forth with it and get a fine tuned answer.
When I used SO I had always just wanted an answer, but had to accept answers that were close, but not quite what I needed.
God forbid if I needed to post a question. I'd immediately get hit with over moderation, or someone closing the question for whatever reason.
I used to be an avid SO contributor up until around ~2015. I saw the mod community turn snarky. AI is just a better way to get stuff done.
So back in 2021 I built a loyalty platform for a chain of gas stations in the Caribbean. Thought it would be a quick deliverable, then hands off.
It's turning into a full time side gig that's paid off in handful of batches (~$25K and running)
I'm trying to become a loyalty vendor API.
Would really like to work on my own interconnected systems of blogging tools and social media. Kinda a blend between having your own site and myspace? Not really targeting a market or anything like that, just think it would be cool to do for personal use and sharing with family and friends
I went to school with the son of the owner. For about 3 years off and on he'd been asking me about building apps, where he could find good devs, what price to pay.
I'd sent him some info, but never got too involved. Then the pandemic hit, and I found myself with a bit more time to kill, so I listened more to what they needed.
They basically wanted to get a loyalty program going at their gas stations and partner gas stations, but wanted custom rules which their current provider couldn't do with their off the shelf solution.
They also wanted to use one of those old school CC machines that were everywhere before the likes of square showed up. But getting your hands on those units is expensieve.
So I started planning it out. They needed to store customer data, and needed a point of sale device to swipe customer loyalty cards on, which needed to read in customer info, do a deduction, or a store credit top up and print a receipt.
I found a android terminal machine off alibaba, opened up android studio and started hacking away. I hadn't done more than a basic android hello world at this point.
For the backend I used django to get started quickly, and they were very happy to use the django built in admin panel to do stuff as needed, and view transactions.
After I got the devices talking to django, I had to integrate a loyalty vendor they already sourced, and just went along with it, but that was a mistake. The vendor points API doesn't really add much value on what django can already do for me, and my new goal is to become that vendor since I think I can do their product better.
But basically I iterated on it for about a year, launched a little over a year ago, still working out some edge cases and kinks, but they do roughly 25K transactions a month on devices spread out at over 20 stores.
They want to bring it to new islands, so I'm trying to remove some of my duct tape fixes with more stable fixes so that can be smooth sailing come next year.
EDIT: Might get back to writing and update with a much longer post. Draft:
Wow, thanks. This is fascinating and it's also a useful outline or storyline for how these sorts of B2B projects come about. Particularly the part about how their current provider couldn't or just didn't want to provide or develop new services or perhaps just didn't see the customer base developing. Driving a wedge between big enterprise solutions and "move fast and break things" guerilla solutions.
[EDIT: Just wanted to add that I'll definitely be circling back to read the rest as you finish it and the lessons learned.]
Nothing much to show other than one client, but I'm on the cusp of charging them monthly vs getting paid by the hour.