Category: Engineering

Book about the Edmund Fitzgerald

by philg

It’s Friday the 13th, a notorious day for bad luck. Speaking of bad luck, let’s look at the 29 men who died on the Edmund Fitzgerald on November 10, 1975. They’re the subject of an interesting new book: Gales of November by John Bacon. Not exactly a spoiler: everyone dies, just as Gordon Lightfoot explained in his enduring hit song (from the book I learned that Lightfoot was an experienced recreational Great Lakes sailor).

Some things that I didn’t know:

  • it was the last trip of what was going to be the retirement year for the captain and many of his long-time partners amongst the crew
  • the captain was considered the best on the Great Lakes and had 45 years of experience
  • the weather was a 50-year event, perhaps, and not merely an ordinary “gale of November”

Perspective on the suffering of Jeffrey Epstein’s victims

Since almost everything in the news these days must be referenced to the Epstein Files…

The sinking was preventable, as we’ll see below, and quite a few mistakes were made.

Columbia offered some of the families the victims’ last paycheck ($568.25 for a deckhand) and $750 for the victim’s lost personal effects, an amount determined by their labor contract, but other families didn’t receive even those checks. When Columbia offered nothing else, the families had little recourse but to file wrongful death lawsuits, for which Columbia paid whatever the families’ individual attorneys could negotiate. Some families received about $35,000, or a little more than a year’s wages for a deckhand making overtime, and others marginally more.

The typical woman who alleged that she suffered by receiving cash, Gulfstream rides, free rent in Manhattan, luxury vacations, etc., in exchange for sex 10, 20, or 30 years earlier, was paid about $3.5 million from Epstein’s estate, a JP Morgan settlement fund, and a Deutsche Bank settlement fund. That’s 100X what an Edmund Fitzgerald crewmember’s survivors were paid. Thus, we can conclude that having sex on Jeffrey Epstein’s island was 100X worse than riding through 30-50′ waves for hours and ultimately being drowned in 42-degree water.

The bargain all the crewmen on the Fitzgerald had signed up for was a hard one, but straightforward: The work will be taxing, and you will miss most of your family’s best moments, but you will retire relatively young, with a good pension and nothing to do but hunt, fish, and play cards, pool, and golf. Best of all, you’ll have plenty of time and energy to spend with your grandchildren. The Fitzgerald’s twenty-nine crewmen and their families had all paid their deposits up front, but never got to enjoy the sweet side of the deal.

The Special Hazards of the Great Lakes

The Great Lakes can be more treacherous than the oceans. One reason is the distinct structure and frequency of the Great Lakes’ freshwater waves. In the oceans, salt weighs down the water, squashing the waves and spreading them out, so they typically form larger but smoother swells, similar to a roller coaster. On the Great Lakes there’s no salt to hold down the waves, so they rise more sharply and travel closer together, like jagged mountains of water coming at you in rapid succession. These waves don’t roll; they peak, crest, then crash down on whatever is unlucky enough to lie below them.

That’s another reason why Great Lakes waves are so steep and ragged and travel so fast. On the ocean the waves are usually about ten to sixteen seconds apart, so even a large container ship can fit between them. On Lake Superior the waves run four to eight seconds apart, which means that a seven-hundred-foot lake freighter can be riding atop two waves at once.

That problem produces more problems. On the Great Lakes a ship that long can impale its bow in one wave, which can lift it up thirty feet or more, while the ship’s stern can be simultaneously stuck in the wave coming right behind it, raising the ship’s back end in the air another thirty feet. That leaves its midsection, which could be loaded with 58 million pounds of iron ore—the equivalent of 4,200 adult elephants—suspended between the two waves, with nothing supporting it. That creates a phenomenon naval architects call “sagging,” in which the unsupported middle of the ship sags toward the water below it, exerting a tremendous strain on the hull.

After sagging between two waves, just seconds later the ship might face another threat: riding over the peak of a single colossal wave. This creates a condition known as “hogging,” the opposite of sagging, where the vessel drapes over the wave’s crest, with both the bow and stern drooping downward, again placing immense pressure on the center of the ship’s hull.

[Michigan Tech’s Guy] Meadows’s research shows that Lake Superior’s biggest storms occur every thirty years or so, but even in milder storms the waves on the Great Lakes can be alarming. In a pretty unremarkable 2020 storm, for example, two of their buoys anchored off Lake Superior’s southern shore, far from the path of Superior’s biggest waves, measured waves reaching 28.5 feet, almost as high as a three-story building.

If the biggest waves within a few minutes are at 30′, according to Guy Meadows, and they stay there for 24 hours, a ship should experience at least one 60′ wave (1 in 10,000).

Another bad feature of the Great Lakes is that it is easier for freshwater to freeze above the waterline on a ship than it is for saltwater to freeze, thus adding weight to a ship that is already in peril. A typical modern iron boat’s cargo of taconite also creates a hazard:

Because it’s two-thirds clay, a porous material, it can absorb up to 7 percent of its weight in water, and four times that can get trapped between the pellets when it’s piled high.

(i.e., the cargo hold can hold a lot of water weight that isn’t possible to pump out; separately, if you thought that math professors were useless, the book notes that U. Minnesota math prof Edward W. Davis is the person who figured out how to work with taconite, a low-grade iron ore)

Overloading as a Factor

Prior to the wreck of the Fitz, Great Lakes captains prided themselves on moving maximum tonnage per trip and per season. Everyone loaded up the ships to the painted Plimsoll line at which point the freeboard is the minimum required for safety. The Fitz was operated with far less freeboard than her original designers had intended:

Given how such incredibly small margins on the Plimsoll line could produce such prodigious gains, especially when multiplied by forty to fifty round trips each shipping season, the executives at Columbia Transportation must have been thrilled when the American Bureau of Shipping (ABS), working with the Coast Guard, reduced everyone’s required freeboard in 1969, and again in 1971, and again in 1973. For the Fitzgerald, that meant the original requirement of 14 feet, 9.25 inches of freeboard when sailing in November had been reduced to 11 feet, 6 inches—a total drop of 39.25 inches, or more than a yard, in just a few years.

Captains would then use various techniques to add a few inches of cargo beyond even this reduced freeboard, described in a chapter titled “Cheating the Plimsoll Line”.

The Edmund Fitzgerald was loaded to the absolute maximum, and a little beyond, on what was supposed to be her last voyage of the season:

The loading speed was all the more impressive because the dockworkers had filled the Fitzgerald’s belly with 26,112 long tons of taconite—far from the staggering amounts the new thousand—footers were carrying, but a fitting finale to McSorley’s celebrated career. The load that day was almost 4,000 long tons more than the 22,509 the Fitzgerald needed to set the Great Lakes record on its very first run just seventeen years earlier, a testament to the extra 39.25 inches the Coast Guard had allowed the Fitzgerald to sink in the water since 1973—plus the crew’s ability to cheat a few more inches on the Plimsoll line. This was such a common practice it would have been more remarkable if the crew had not cheated on the Plimsoll Line. Even the crew’s families knew about it. “They were overweight because they wanted to break their own record,” says Blaine Wilhelm’s daughter, Heidi Brabon. “So they cheated.” But what was unusual, according to former Fitzgerald deckhand Terry Sullivan, was that she was carrying a full load so late in the season, when even the USCG rules start scaling back the limits. While the Fitzgerald might not have been cheating by much, on the grand scale, when you combine those extra inches, plus the 39.25 inches the Coast Guard had already granted the Fitzgerald two years earlier, and the fact that all ships were supposed to scale back their loads for the rougher fall weather, any reasonable analysis can draw only one conclusion: The Fitzgerald had loaded thousands of tons more than what her architects had designed her to carry.

Primitive weather forecasts and distributions of forecasts

One of the blessings of the semiconductor revolution kicked off by William Shockley and carried forward by Jack Kilby is that computers have gotten vastly more powerful, thus enabling weather forecasts to become more reliable even without any advances in our understanding of meteorology. The National Weather Service was consistently late and consistently underestimating the strength of the storm that would sink the Fitz.

That afternoon [Sunday, November 9, 1975] the National Weather Service had posted a “gale warning,” a level of caution the NWS had created after the 1913 Storm of the Century showed it needed intermediary warnings, not just hurricane alerts. A gale warning predicts winds blowing thirty-nine to fifty-four miles per hour. But the NWS projected the wind would barely reach the gale range, which meant about forty miles per hour.

By 7 p.m. the National Weather Service noticed the storm system that started out of California had reached Iowa, and was gaining speed. It issued a gale warning for all of Lake Superior, correcting its earlier prediction that the storm would slip just below the big lake. Now, the NWS meteorologists said, the storm would cut diagonally across Lake Superior, producing waves from five to ten feet. That might not sound like much, but because the Fitzgerald had only 11.5 feet of freeboard, ten-foot waves wouldn’t give the ship much margin for error.

Late Sunday night the National Weather Service revised its forecast again, now predicting that waves Monday morning would reach ten to fifteen feet high. At 2 a.m. the NWS escalated its gale warning to a storm warning, reserved for winds expected to reach fifty-five to seventy-three miles per hour—strong enough to tear off roofs, uproot large trees, and knock over people attempting to walk outside. But the reality on the water was already starting to outpace the NWS’s forecasts. Winds on Lake Superior had already surged past fifty-eight miles per hour, and were still accelerating. The storm was gaining power like a boulder thundering down a steep hill.

[at 4 pm on Monday, November 10] Captain Cooper, now running an hour behind the Fitzgerald, later reported waves “up to twenty-five feet” when the Anderson neared Caribou Island. Since the Fitzgerald was now about twenty-five miles and an hour and forty minutes beyond the coordinates whence the Anderson had made that report—that much closer to the safety of Whitefish Bay, but also the storm’s epicenter—the waves the Fitzgerald was now experiencing were probably worse than the twenty-five-footers the Anderson had reported. Because the Fitzgerald had only 11.5 feet of freeboard, and probably less by the hour due to its compounding problems, those waves would be more than enough to wash green water—entire waves, not just the spray—over the Fitzgerald’s deck.

The Fitz sank at about 7:10 pm.

Get-there-itis

Some captains put in at Thunder Bay after realizing that the storm was

Full post, including comments

Shout-out to our brothers, sisters, and binary-resisters in Minneapolis

by philg

Some gratitude to the good people of Minneapolis. The city’s martyrs of ICE resistance, such as Alex Pretti and Renée Good, are apparently forgotten because Donald Trump briefly posted part of a “king of the jungle” video (apparently suppressed by the righteous who run YouTube, but available from the haters at X). Front page of the NYT today condemning Trump for his racism; nothing anywhere on the front page about Minneapolis, as if the sacrifices were for nothing:

I will celebrate Minneapolis, therefore, with a shout-out to SANUS, headquartered in suburban Minneapolis (a 3-minute drive from the Al-Amaan mosque). Mere hours before we were to our Super Bowl extravaganza guests are arriving, our four-year-old $900 Costco 86″ TV wouldn’t turn on. Thanks to the Sanus BLT3-B1 “tilt 4D” mount, however, I was able to pull the recalcitrant machine from the wall and use my Ph.D. in EECS skills to unplug it and plug it back in. The kids are watching the Puppy Bowl and, if the Costco gods are with us, the party will proceed as planned.

I suppose that we also have to celebrate our brothers and sisters in China (not too many binary-resisters there) for actually making the Sanus BLT3-B1 so that it cost $100 instead of $300.

(I do wish that ICE would detain and deport whoever made the Xfinity XG1v4 box, which I picked up because of its advertised 4K capability. It needs to be power-cycled almost every time that we want to use it and the boot-up process is almost 10 minutes.)

Let this be a cautionary tale for anyone who is considering a super-slim wall-hugging TV mount that requires professional skills and multiple humans to execute a dismount and reach-around. (I guess we could have accomplished the power-cycle via flipping breakers. I’ve never seen a behind-the-TV outlet that is associated with a convenient switch that could be used for a convenient power-cycle.)

Finally, maybe this is the time to start an extended warranty claim on the TV? It was a floor model at Costco and they threw in a five-year warranty from Allstate. The warranty was already used once to replace the TV’s main board, possibly a casualty of a lightning storm putting high voltage into the Xfinity cable (another good reason to go with a fiber connection if you’re lucky enough to live in a place where fiber is available).

Loosely related

From the masjid around the corner from Sanus, a Facebook post from one month after the Gazans’ peaceful October 7, 2023 excursion into Israel:

Allah is the All-Mighty, the Most Merciful, the One Who has the absolute ability to save the oppressed, inflict punishment on the criminals and stop the brutal massacre and genocide happening in Gaza.

It’s a challenging theological question. Allah is “All-Mighty, the Most Merciful” and with “the absolute ability to save the oppressed” (redundant with “All-Mighty”?). Yet the genocide happening in Gaza wasn’t stopped until the Gazans had suffered the loss of most of their military capability. Why did Allah wait two more years and, perhaps more importantly, not assist the Gazans in realizing their military goals, including the destruction of the Zionist entity and the establishment of Hamas rule from the river to the sea?

Full post, including comments

Greta Thunberg tennis court (solar panel sunshade)

by philg

Happy National Cut Your Energy Costs Day to those who celebrate.

An idea for how to be simultaneously more virtuous and comfortable: a Greta Thunberg-branded tennis court shade. ChatGPT says that some fabric shades have already been made and they should be about 45′ high to avoid interference with lobs (50-65′ at the pro level). ChatGPT says that it would be stupid expensive to engineer this in rigid solar panels, especially if there is a need for the structure to survive a hurricane, but on the other hand we’re told that the only way to save Planet Earth from going Full Venus is to do stupid expensive stuff. Florida’s Broward County (home to FLL) has covered two basketball courts with solar:

They say that what was, very likely, an eye-watering outlay of tax dollars is “a visible reminder of how sustainable infrastructure investments can benefit both people and the planet while saving on energy costs.” (If there truly were net savings on energy costs wouldn’t we see these all over Florida, Arizona, Nevada, etc., and not just in this one park?)

If there is a big influx of tax base thanks to Zohran Mamdani, I’d love to see more of this in Palm Beach County. ChatGPT says that it could conceivably work for pickleball (required height only 18-22′).

Separately, some folks are working on tennis coach robots, e.g., ACEMATE and Tenniix:

ChatGPT’s explanation of why a tennis Greta Thunberg-brand shade can’t be affordably engineering to Miami-Dade hurricane standards:

Why it’s hard (and what makes it “expensive hard”)

1) Wind uplift loads get huge, and PV is a rigid “wing”

ASCE 7 treats canopies/roofs with net uplift pressure coefficients (negative pressures trying to peel the roof off). Canopies got more explicit treatment in ASCE 7-16 and later. Structure Magazine+1

For a big, flat-ish PV canopy:

  • Uplift (psf) scales roughly with V2V^2V2.
  • Going from 120 mph to 170 mph isn’t “+40%”—it’s closer to (170/120)² ≈ 2.0× the pressure.

Fabric shades can “spill” wind; PV cannot. The PV roof transfers that uplift straight into:

  • purlins/joists
  • primary girders
  • columns
  • foundations (uplift + overturning)

2) Height required for tennis multiplies overturning

Tennis-friendly clearance is typically ~40–50+ ft so you don’t ruin lobs/serve sightlines. That height makes the wind problem worse because:

  • the structure “lever arm” increases → bigger overturning moments
  • columns behave like tall masts, not “carport posts”

A PV canopy that might be straightforward at 12–16 ft (parking) becomes much heavier at 45–55 ft.

Full post, including comments

Occupancy sensor-based per-room water shutoff?

by philg

Loyal readers may recall the failure of our Moen Flo whole-house water shutoff system to detect a drip. How about a more granular approach?

Have a flow sensor and shut-off valve for every room in the house in which there is plumbing, e.g., kitchen, laundry, bathrooms.

Put an occupancy sensor in each of the above rooms and, for the washing machine, a current sensor at the plug to tell if the machine is on. (Alternatively, use the network of cameras that a home should have for assisting with misplaced objects.)

Now the system doesn’t have to be that smart. If there is a sudden water draw from a bathroom that isn’t occupied then shut off the water to that bathroom. Have an override switch by the main light switch, of course, in case AI isn’t as smart as imagined.

How could one do occupancy sensing without either a massive privacy issue or an uglification of the house? Here’s an outlet that combines app-switchable power, night light, CO2 and VOC measurement, temp and humidity sensor, and occupancy sensing (via radar):

(Legal to install in a bathroom or kitchen counter, I think, if there is a GFCI circuit breaker.)

What’s the obvious flaw in this plan? Given that insurance companies will give a discount for the Moen Flo, which will allow at least hundreds of gallons of water to trash a house before it does any shutting off, I would think that insurance discounts over the years would more than pay for all of the tech. I guess there is an ongoing maintenance hassle, especially if flow is measured via impellers. Still, when you consider the $200,000+ cost of cleaning up after a flood, I think it is worth it.

Full post, including comments

Why isn’t there a simple 5-channel or 7-channel amplifier that connects to a television’s HDMI eARC output?

by philg

Our family room TV is almost impossible to use due to the fact that the hub of the system is a Yamaha RX-6A AV receiver with a complex user interface and many functions that overlap with the TV. What’s worse, the Yamaha has already had one HDMI switch board failure and seems to be on track for another one (the receiver is about 3.5 years old and sells for almost exactly what we paid for the vastly-more-useful and vastly-simpler-to-use 86-inch LG TV, i.e., $800 (we got the TV at Costco 3.5 years ago for $900, but they threw in a five-year warranty that should have been worth about $100).

What functions of the Yamaha do we actually want? We want it to switch among HDMI inputs and amplify sound for five passive speakers. If we had a subwoofer we’d want it to provide a line-level output for a powered subwoofer. A modern television already supports HDMI switching, typically among 4 inputs, which is plenty for 99% of consumers (cable TV box, some sort of dongle, maybe a slide show player). The modern television also puts out multi-channel audio and volume control commands via its eARC HDMI output. From ChatGPT:

Given how cheap Class D amplifiers are and how inventive Asian electronics companies are, I can’t figure out why there isn’t a display-free and remote-free 5- or 7-channel amplifier with a line-level subwoofer output that could take eARC with Consumer Electronics Control (CEC) input and drive one’s legacy passive speakers. This would enable consumers who’ve cut their cable cords to enjoy true surround sound with just one remote control. As a minor enhancement, when the TV is off and eARC has no signal the little amp could offer to play a Bluetooth source, e.g., from a phone app, through the two main speakers.

There must be something wrong with this product idea because nobody makes a “keep the TV at the center of the TV-watching system” amp. But what is the flaw?

Full post, including comments

Could we shade the Earth or at least some cities now that Starship is working?

by philg

Elon Musk wants to go to Mars on Starship. What can the technology do for those of us who aren’t interested in living on Mars? How about improving our beloved Earth, or at least the biggest and richest cities, via space-based sunshades? If we wanted to help everyone on the planet we could put a 35kTon shield at the L1 Lagrange point (#Science).

But if we’ve learned nothing else from the Climate Change (TM) experts we’ve learned that the climate righteous don’t care about everyone on the planet. Greta Thunberg, for example, cares only about the noble Palestinians (today she sails to Gaza from Spain). Climate change alarmists in New York City were in favor of open borders when migrants invaded Texas and against open borders (“a crisis”) when migrants began showing up in NYC by the busload to claim their right to taxpayer-funded housing.

What about space-based sunshades funded by the richest and most densely packed cities that are aimed at cooling off only folks in those cities and only for the hottest months of the year? Grok says that New York City could be shaded for less than $5 billion. If we assume that 1 million NYC residents (out of 8.5 million) pay non-negligible taxes, that’s $5,000 per taxpaying New Yorker, essentially nothing. It’s also nothing compared to the NYC government’s $115 annual budget. Maybe Grok is wrong about the likely cost? Or Grok is budgeting for 20 years of improvements in technology?

Unlike air conditioning, a solar shade for the elite has the advantage that it will also cool off non-elite regions of the Earth, at least to a small extent. The constellation of sun shades for NYC could move to provide relief to equatorial cities in the spring and fall and then be repositioned to provide shade to Southern Hemisphere cities during their summer. Maybe a city could still hit 95 degrees due to being near a warm air mass, but there wouldn’t simultaneously be a blazing hot sun. Grok says we can get a 3.5-7-degree F local temperature reduction.

Where else could this work? I.e., what other cities tend to be too hot for some parts of the year, are densely populated, and are rich? Singapore, Shanghai, Hong Kong, Tel Aviv (cue the Jewish Space Lasers!), Dubai, Abu Dhabi, Miami, Doha, Tokyo?

Here’s Grok’s answer after I asked about shading all of Florida and then just NYC:

Technical FeasibilityBuilding a space-based sunshade for New York City (NYC, approximately 800 km² land area) that deploys seasonally from June 1 to September 15 is theoretically possible but would require significant advancements in solar sail technology and orbital mechanics. Unlike global sunshades at the Sun-Earth L1 point (1.5 million km away), a city-specific system would use a constellation of smaller, lightweight reflective sails or mirrors in Earth orbit to provide targeted shading. This draws from early concepts like Hermann Oberth’s 1920s-1970s proposals for orbiting mirrors (100-300 km diameter) to weaken solar radiation over specific regions.

Modern adaptations could leverage “statite” configurations—solar sails that balance solar radiation pressure against gravity to “hover” over fixed points, such as high latitudes.

Design and Deployment: A constellation of 10-50 sails (each 10-50 km², depending on orbital altitude) could achieve 20-50% insolation reduction over NYC during summer daylight hours. Sails would use ultra-thin materials (e.g., polymeric films with SiO₂ nanotubes, areal density ~1-4 g/m²) for reflectivity. For seasonal use, sails could be oriented edge-on to the Sun (non-reflective) outside summer, or maneuvered into storage orbits using onboard ion thrusters or solar pressure. Deployment might involve launching folded sails from Earth, unfolding in orbit, and positioning via solar sailing—reaching operational orbits in weeks to months.

Orbital Configurations: To maintain persistent shading over NYC (40.7°N), sails could use inclined geosynchronous orbits (24-hour period) or Molniya-like elliptical orbits to linger overhead during daylight. Statite modes could allow quasi-stationary hovering by tilting sails to counteract gravity, enabling seasonal activation without full repositioning.

Studies on L1 sunshades show orbiting disks can mitigate seasonal temperature variations by ~0.5-1°C globally, suggesting adaptability for targeted summer cooling (e.g., reducing NYC heat by 2-4°C).

Size and Materials: Total sail area might be 500-2,000 km² for effective shading, far smaller than global proposals (3-4 million km²). Advanced sails (reflectance >90%) could minimize mass to 1,000-5,000 tons, deployable via reusable rockets like Starship.

Challenges and LimitationsEngineering and Launch: Solar sail tech is nascent (e.g., NASA’s Solar Cruiser prototype); scaling for precision control over a city requires breakthroughs in attitude control and collision avoidance. Launching via 50-100 missions (at $50-100/kg) could take 5-10 years, with risks of orbital debris exacerbating Kessler syndrome.
Cost: Estimated $500 million to $5 billion, based on scaled-down global figures ($5-10 trillion for planetary-scale).

This includes R&D ($100-500 million), launches, and maintenance. Seasonal operations add complexity, potentially increasing costs by 20-30% for repositioning fuel/thrusters.
Environmental and Ethical Issues: Targeted shading could alter local weather (e.g., reduced rainfall or photosynthesis impacts), affect solar energy production, or cause uneven cooling in adjacent areas. Global governance is needed, as unilateral deployment raises international concerns. Sudden failure (e.g., solar storm damage) could lead to rapid warming.

Current Status: No prototypes exist for regional shading; efforts focus on global concepts via groups like the Planetary Sunshade Foundation.

Implementation might be viable in 20-30 years with investments in reusable launchers and in-space manufacturing.

In summary, while conceptually sound and more feasible than Florida-scale due to NYC’s smaller size, this remains speculative geoengineering. Ground-based alternatives (e.g., cool roofs, urban trees) offer quicker, cheaper relief.

Sustained R&D could make it a complementary tool for urban heat mitigation.

Related:

Full post, including comments

Credentialed expert consensus: SpaceX Starship will never work

by philg

Two months ago, New York Magazine Intelligencer (“intelligence” even in the name of the publication), “Is Elon Musk’s Starship Doomed? The future of SpaceX keeps blowing up, and no one knows if he can fix it.”:

“Having a rocket ascend a few hundred meters and blow up is not a success to me,” says Dallas Kasaboski, an analyst who covers the space industry for the research firm Analysys Mason.

Reusing both parts of a rocket, instead of just one, sounds like a modestly more ambitious undertaking — if you can do it once, why not twice? — but in fact, it’s exponentially harder, since the amount of energy to be dissipated while returning to Earth goes up not as a linear function of velocity but its square. The energy gets turned into heat, which sends the temperature of the Starship soaring into the thousands of degrees, such that it glows white-hot. To reduce the effects of this heat, the rocket’s exterior is coated in thermal tiles. But these are heavy. So is the internal bracing required to hold the ship together during the turbulence of reentry.

For critics, like Substack writer Will Lockett, the fact that Starship has failed so many times in a row is proof that the concept is fundamentally unworkable. “SpaceX is having to make the rockets too light, resulting in them being fragile, meaning that just the vibrations from operation with a fraction of its expected payload would be enough to destroy the rocket,” he wrote in one typically acerbic post.

“I remember reading a book in the 1970s about how the space shuttle would be flying every two weeks and cost low hundreds of dollars per pound to orbit,” says Grant Anderson, co-founder of the space-systems-maker Paragon Space Development Corporation, which helped launch SpaceX in 2002. “It never did that, obviously.” … When would we know if Starship is toast? One major red flag is persistent failures. “If you have a failure at the same stage twice for the same reason, and they can’t solve the problem, that’s an indication that there’s a design flaw that’s more than just an ‘Oops!’” says Anderson.

Readers: What do you think? Is it possible that Elon Musk and SpaceX are right and the expert consensus is wrong? Is there any way that Starship could one day make it into orbit without exploding? And, perhaps one day many years or decades from now, that both booster and Starship could land back on Earth?

Full post, including comments

The revolution in oil-powered general aviation is at least three years away

by philg

Happy National Aviation Day to those who celebrate.

One thing that you’d expect the Experimental Aircraft Association, with revenue of more than $60 million per year, to do is fund the development of new powerplants. There has never been any significant progress in aviation without first an improvement in engines. A low-power high-efficiency turbine engine, for example, would enable the creation of all kinds of dramatically superior aircraft. But none of the kit companies or even the certified four-seat aircraft companies can readily afford to invest what is required.

Enter Turbotech, a startup in the Islamic Republic of France. They say that they have a 140 hp turboprop engine that burns fuel at approximately the same rate as a 140 hp Rotax (piston) engine:

How long before this can be dropped into a certified airframe? The founders said that if everything goes perfect and nothing at all has to be changed in their current design, the engine could be EASA/FAA-certified in three years.

An analysis with some numbers (I disagree with the price discussion):

I don’t think it is Turbotech, but the Canadians claim to have a “turboshaft engine” in their Janus-I Flying Suitcase:

The ultimate license plate for light aircraft enthusiasts (a car parked at Oshkosh and, presumably, that will seen at Sun ‘n Fun in Lakeland, Florida in April:

Full post, including comments

Measured cooling effect of clay tile roof

by philg

I have a Chinese Govee temperature sensor above the fiberglass insulation in a mostly unventilated attic here in Florida. During a reroof there were periods of time when the attic was covered with

  1. concrete barrel tiles over hot mop tar paper
  2. modern peel-and-stick underlayment only
  3. clay barrel tiles (a medium-dark red/brown) over the modern underlayment

Weather conditions were reasonably consistent during these three time periods, i.e., hot and sunny.

Temps in the lower part of attic (only about 4′ high; probe on top of some fiberglass insulation above the finished ceiling) went from roughly 100 degrees underneath the old intact roof (concrete tiles) to 120-130 degrees under the peel-and-stick underlayment only (white in color, but apparently not very reflective), and back down to around 100 degrees underneath the new clay tiles over underlayment. Here’s a chart from the Govee app:

In late July, maybe the hottest time of year, the temps went up to a max of 115 degrees.

Speaking of Chinese tech, here’s an idea for an awning that can automatically deploy over a parked car:

(I hope that it checks the wind forecast and the actual wind and folds itself up automatically when necessary!)

Full post, including comments

Transforming human waste into agricultural solutions

by philg

It’s a right-wing conspiracy theory that elites want to keep expanding human population until the peasants are forced to eat bugs. Debunking this theory, a recent article in MIT’s Technology Review, “How poop could help feed the planet”:

Nutrients crucial for agriculture are in “short supply,” but certainly there is no reason to close the border to low-skill migrants or reconsider the goal of another doubling of U.S. population:

(Note that the 340 million people might be an underestimate of 10 million undocumented humans or more; see “Yale Study Finds Twice as Many Undocumented Immigrants as Previous Estimates” (2016 data).)

Could this possibly work? If you live in Seattle you’re already eating food derived from human poop:

A recent review in the Journal of Environmental Management, in fact, touts wastewater treatment plants as “renewable biological nitrogen mines” that can supply the essential but expensive component from reclaimed sewage sludge at a time when many farmers are finding it harder to obtain. Sewage can, the authors conclude, “become an important raw material for the sustainable production of organic-mineral fertilizers from renewable resources available locally, with a low carbon footprint.” Extracting nitrogen and phosphorus for reuse can also help remove those pollutants from the plants’ outflow and reduce the amount of organic matter destined for landfills and manure lagoons, which store and manage huge concentrations of livestock waste. Reinserting ourselves into nature’s recycling system, in other words, could help us meet the planet’s growing food needs without unduly fouling the environment.

The Varcor system heats the incoming poop and separates it into solid matter and vapor. A process called mechanical vapor recompression allows the compressed steam to be reused as a heat source while the water and ammonia vapor are separated and distilled. The conveyor belt/dryer carries the remaining solids to the giant crepe-making spindles and then into a waiting truck below. The plant is now selling three to four truckloads of this dry fertilizer to farms every week.

What’s happening with the population collapse that Elon Musk keeps warning about? It’s exacerbated by what the Technology Review authors call “the planet’s burgeoning population”:

Waste-to-fertilizer strategies, even if scaled up, won’t be enough on their own to help feed the planet’s burgeoning population. By viewing people as not only consumers but also producers, however, they could help us take far better advantage of some underrated natural assets that won’t run dry anytime soon.

Full post, including comments