Someone I follow on Bluesky recently posted about an absurd demand from her HR department. Her post reminded me of similar experiences in my own 33-year career in Government. One event that still stands out after twenty years was the demand that we begin reporting our monthly number of “capabilities delivered.”

“Capability delivered” sounds like a reasonable thing, but I was in a group writing small-to-medium software tools. Those two vague little words could describe anything we did, from writing small spreadsheets for ourselves to delivering finished products to external customers. Foolish mortal that I was (and still am), I asked for clarification. What counts as a capability? What counts as delivery? If I send the same software to twenty people, is that one delivery or twenty? My request was rebuffed, and it wasn’t hard to guess why: The people I asked didn’t know either. Some Big Boss had shouted, “Minions, fetch me the monthly number of capabilities delivered!” and the minions had scrambled to obey without asking for clarification. From that, I drew three conclusions:

1. Without a meaningful definition of “capabilities delivered,” the resulting count would be meaningless. (“Garbage In Garbage Out” for those who know the idiom.)
2. The Big Boss needed numbers that made him look better than other Bosses.
3. The minions had unwittingly dared me to conduct an experiment.

I decided to report a test number and see what happened. If the minions had an unspoken definition of “capability delivered,” they might complain that my answer was too high or too low. But if my answer satisfied them (or fell into apathetic hands), I would hear nothing.

I needed a believable test number, so I chose 17. It’s odd. It’s prime. And for some reason, it doesn’t sound like a guess. But I didn’t just throw that number at the minions and call it a day. I reviewed my monthly work log and identified 17 things that could be called a “capability delivered.” Now I had a defensible position. If anyone complained about my answer, I could point to 17 things I had actually done and say “I thought that’s what you meant.” I sent in my answer and heard nothing back. The next month, I did the same thing. And the next.

For the next year and a half, I reported 17 “capabilities delivered” every month, and I never heard a word back from anyone. Then the minions abruptly stopped collecting numbers. Apparently they had fulfilled their mysterious purpose in the oxygen-deprived heights of the bureaucracy. (That goes for both the numbers and the minions.)

And that’s the Rule of 17. If you’re asked for a bullshit number, don’t invest yourself in it. While everyone around you is sweating bullets over some ill-defined request, remember that you have a limited number of seconds in your life. Grab a clipboard and walk briskly. (It makes you look productive.) Go out to lunch. Take a walk. Give blood. Do something fun. Then come back and answer 17. You’ll look like you know what you’re doing. And you do know–you’re putting the right amount of work into a meaningless request. It may feel like slacking, but the people who asked the question were slacking even harder. Otherwise they’d have given better instructions.

In the past few years, the excitement around electric airplanes has made it difficult to separate hype from facts. But rejoice! We finally have a real electric airplane to talk about. It’s not a prototype for airshows and venture capitalists. It’s for sale. It flies at real airports. And it’s built by a manufacturer who’s been in the business for decades. Writer and pilot Sarah Deener describes flying the Pipistrel Velis Electro in the January 2024 edition of AOPA Pilot magazine. If you can’t find a copy in your local library, check out your local municipal airport (the little one with flight schools, not the big one with commercial airlines). Look in the stack of magazines beside the comfy chair in the lobby. The article won’t take long to read and provides many of the numbers I discuss below.

Before we get into it, I want to back up and review two key points. The first is that batteries aren’t “gas tanks for electricity.” Gasoline tanks are simple, inert containers that last for decades. Batteries are expensive chemical reactors that decay each time they’re drained and recharged. Eventually they decay to the point where they have to be replaced. And in high power applications, they often need artificial cooling.

The other important piece of background is that batteries are heavy. Seriously heavy. It takes a 50-pound lithium battery to match the energy in a single pound of gasoline (one McDonald’s medium drink cup). But since electric motors are 3 to 4 times better at converting energy into usable work, it takes 3 or 4 pounds of gasoline to do the same work as a 50-pound battery. That reduces lithium’s weight disadvantage from 50-to-1 down to about 14-to-1. In general, gasoline will take a vehicle 14 times farther than the same weight of lithium batteries. To get useful ranges, electric cars compensate with batteries weighing 800 to 1700 pounds, far exceeding the 96 pounds of gasoline in a typical 16-gallon tank.

Adding batteries to an airplane isn’t like adding them to a car. The weight carried by an aircraft is strictly limited by the ability of the wings and powerplant to create lift. If you want to add more batteries, you have to lose weight somewhere else, carrying fewer passengers or less cargo. Or you can build a bigger airplane, but that just drains the batteries faster.

What about the actual electric airplane?

The Electro is a light, two-seat, high-wing aircraft. Its liquid-cooled batteries weigh 300 pounds. The pilot and passenger are limited to 378 pounds (total), and that’s all the Electro can carry. On the demo flight, the pilot did four takeoffs/landings and flew some common training maneuvers. The entire flight lasted 29 minutes, during which the battery went from Full down to 27%. (In other words, the flight used 73% of the battery capacity.) In round numbers, that’s 30 minutes of flying for 3/4 of the battery, which suggests a full battery could fly 40 minutes. The Electro’s advertised flight duration is “up to 50 minutes,” which might be achievable with a less-than-full-power takeoff and gentle flying.

How much does an hour of flight cost? The Electro flew level using 30 kilowatts of power. (For comparison, that’s 16 household blowdryers running on high.) Doing that for an hour takes 30 kilowatt-hours. On average, that would cost $6 in the USA, which sounds fantastic. But the batteries also need to be replaced every 500 hours. The article didn’t give a price, but other sources in the trade press say the cost will be $20,000. Divide that by 500 hours and you get another $40/hr for a total of $46/hr.

How does that compare to gasoline? The Electro’s nearly identical cousin–the Pipistrel Velis Club–has a combustion engine that burns 5 gallons an hour of unleaded automotive gasoline. That costs about $20/hr where I live. Regular oil changes and spark plug replacement raise the cost to $24/hr. The Club can fly 5.5 hours on 26 gallons (156 pounds) of gasoline. With 300 pounds of gasoline (the same weight as the Electro’s battery), it could fly 11 hours. Compared to the Electro’s 40 minutes, that’s a ratio of 17-to-1. If we believed the advertised duration of “up to 50 minutes,” the ratio might be 13-to-1. Either value is close to the 14-to-1 prediction.

People think aircraft wings are a great place for solar cells, but solar energy isn’t the panacea many people imagine. In the middle of a bright sunny day, solar cells on the Electro’s 10 square meter wings might produce 2 kilowatts of power. That’s less than 7% of the 30 kilowatts it needs. At best, solar cells might extend a 30-minute flight by 2 minutes. But in aircraft, weight always consumes energy, and the added weight of the solar cells could actually reduce the range, especially on days without direct sunlight. [The contribution of solar cells is even worse for larger aircraft. Solar cells on the 500 square meter wings of a 747 would (at best) produce 100 kilowatts, less than 1/400th of the roughly 45,000 kilowatts the 747 needs.]

How far can the Electro go? The airplane is intended to fly in the immediate vicinity of an airport. Period. Pipistrel is very clear that if you want to fly cross country, you’ll need a gasoline-powered airplane. Even when flying close to an airport, the Electro is supposed to land once the battery is down to 30%, just like the flight in the article. People are trying to use the Electro for flight training since it can’t do much else, but I think it’s a bad fit. Having recently been a student, 30 minutes isn’t long enough for an effective lesson. There are too many logistical details in simply getting airborne (and landing again) without attempting to sandwich an effective learning experience in the middle. And since recharging takes two hours, the number of flights per day is very limited.

All in all, the Electro’s 40-minute range didn’t surprise me. I’ve been doing the battery math ever since I considered electrifying my first Subaru in the 1990s. And these physical limitations aren’t unique to the Electro. Any airplane with the same size and payload would need the same power to stay airborne, and any decent 300-pound lithium battery would deliver that power for 40 minutes. That’s enough for a few demonstration flights in a day, like a jet pack, but it’s not practical aviation. A practical electric airplane will have to wait for the next big breakthrough in battery technology–either that or Mr. Fusion.

And that was supposed to be the end of this post. Then I thought again about landing with 30% of the battery. Out of 40 minutes in the battery, that leaves just 12. It gave me the wiggins, because landing is stressful enough without knowing you might not have enough fuel to go around and try again.

Airports can close without warning. If you’re second-in-line for landing and the airplane in front of you blows a tire on the runway, you don’t land beyond the wreckage. You stay in the air. The runway is closed until the obstacles have been cleared. That’s one of the reasons airplanes are required to carry at least 30 minutes of extra fuel (more for commercial and night flights). But an airplane on its last few minutes of battery wouldn’t have time to go anywhere else. The pilot would have to declare an emergency and make a forced landing despite the emergency vehicles and personnel on the ground.

Lithium batteries barely contain enough energy to provide a 30-minute safety margin, and people are shaving that margin to create the appearance of longer flight times. I might as well say it out loud: “What could possibly go wrong?”

I was considering Thankfulness yesterday, and my thoughts spiraled into reflections on what I want to be doing with my life. My highest priority is providing a good home for my wife and her menagerie. Then there’s writing. And now I have the opportunity to build an airplane of my own, something to keep me sharp as I cross into the latter half of my 60’s. My health is good, and there are years ahead of me.

But what I’m doing now is checking Twitter and Bluesky, and watching clips on YouTube. I haven’t worked seriously on my current novel in weeks. I haven’t flown in over a year because I don’t trust rental airplanes.

John Scalzi recently compared the different social media platforms to the different tables in the high school cafeteria: the tech nerd table, the popular girl table, and so on. To me, the essence of that comparison is not the tables but the cafeteria itself: noisy, discordant, and in the end unsatisfying. For every delicious tidbit, there are steaming pots of limp pasta and overcooked kidney beans. For every creative soul, there are busloads of dreary cultists and aimless sheep. Social media is nice for keeping up with the creators I know, but it invariably exposes a horrifying panorama of human drama, foolishness, and suffering.

So it’s time to focus on being the person I want to be. I’ll post here as interesting things happen in my life and announce them on Bluesky, but I won’t be present otherwise. I won’t delete the Twitter account, but this will be the last thing I put there.

The last novel didn’t sell, but the next one might. Building my own airplane will give me something I can trust because I know it inside and out. And it’s time to go downstairs and help Meg with Thanksgiving.