How my car wipers work

Yesterday, it actually rained! So I got to use the long-neglected windshield wipers on my Chevy Volt. They have options that include OFF, INT (intermittent), LO, and HI:

“Intermittent” is the tricky one. There are five options shown by the horizontal white bars. Do they indicate how frequently the wipes happen? Or do they indicate the delay between wipes? Effectively, in which direction does the scale increase? I can never remember this, so every time I end up trying out different settings to re-learn how to use my wipers. In this case, a bigger white bar (bottom) means more frequent wipes, which is the reverse of the order implied by “HI” being on top.

And what’s up with the exponential growth implied by the white bars? Is that real?

As Francis Bacon might have said, “When in doubt, collect data.”

I timed the delay between wipes for each of the five settings. And here’s what I found:

If we invert this to report wiping frequency in number of wipes per minute:

So, nope, the labels on the control do not reflect actual frequency. I’ve been reading Edward Tufte’s book titled The Visual Display of Quantitative Information, and this would be a perfect example of what he calls graphics without integrity. One of his principles:

“The representation of numbers should be directly proportional to the numerical quantities represented.”

Boo, Chevrolet designers! And especially for inverting the order with respect to the “LO” and “HI” markings.

The American Civil War: Motivations, soldier parole, and the Supreme Court

I recently attended a lecture at the Huntington by Prof. Emeritus Gary Gallagher of the University of Virginia. He is visiting the Huntington and doing research for his next book. His lecture was on the Civil War, one of his personal areas of expertise. And let me tell you, it is so fun to listen to someone who sincerely *gushes* about their area of expertise. Prof. Gallagher has spent decades studying and sharing his analysis of the Civil War. He’s written eight books so far and is still going strong. Prof. Gallagher lectured without any visual aids, reading from sheets of notes – but the lecture was far from boring. It is clear that he *loves* talking about the Civil War! So passionate!

I took away several interesting thoughts from his lecture. First, he exhorted us not to refer to the “North” and the “South” but instead to “The United States” and “The Confederacy.” Think for a bit about what that means. :)

He also argued that the Civil War was primarily fought over the issue of Union, not Abolition (slavery), although over time historians have shifted to placing more weight on the latter. “Union” here refers to philosophy and politics. One might reasonably ask, if 10 or 11 states wanted to leave the Union, why not just let them? Why did the United States go to bloody war to fight to keep states that didn’t want to be there? Because, he argued, the United States’ “Great Experiment” was threatened. What is a democratic republic if members can simply opt out when they don’t like the outcome of an election? Wouldn’t that prove that our form of government was unworkable? People fought to keep the nation together, which on the face of it sounds a bit abusive. But then again, what war isn’t?

There was also an economic rationale. The Confederacy consisted of the richest states (in terms of per-capita white wealth). South Carolina and Mississippi between them controlled $3B of the economy, while northern industrial activity collectively spanned only $2B. Letting the Confederacy secede would be an economic blow.

Another fascinating topic covered in this lecture were the “parole” arrangements. Neither side wanted to take or be burdened with prisoners of war. So after each battle, they would tally up how many each side captured, and if the numbers were equal, they exchanged prisoners back; but if they were unequal, the extra prisoners would be returned as parolees. These men signed agreements that they would become non-combatants. They were kept in prison camps *on their own side*. They could be re-activated as combatants if their side captured more men from the other side (since then they could be “exchanged”). Imagine!

And finally, Prof. Gallagher noted in passing that President Abraham Lincoln appointed no less than *five* Supreme Court Justices during his presidency. The first was due to a vacancy when he assumed office. Then Justice McLean died and Justice Campbell resigned to join the Confederacy. In 1863, Congress apparently expanded the court to hold 10 Justices (!! The Constitution does not dictate the size of the Court) so he got to appoint another one. Then Justice Taney died, bringing the total Lincoln appointments to five. This is astonishing, and no doubt fueled the Confederacy’s ire. Consider the implications of such an occasion in the light of today’s politics.

Every little bit counts

Did you know that there’s a gigantic concentration of trash that’s swirling around between California and Hawaii? The “Great Pacific Garbage Patch” is a stunning conglomeration of trash that is now reputed to cover an area twice the size of Texas, or possibly three times the size of France. Appalling!


Great Pacific Garbage Patch

Fascinating video about how they measure the volume of trash:

I recently listened to another fascinating episode of the “Science Vs” podcast titled “Plastics: The Final Straw?”. The tale of where our plastics go and what havoc they wreak is not for the faint-hearted. The show also discusses a question that had puzzled me a bit – how could that much plastic possibly end up in the ocean? Apparently, much of it is trash that folks drop in a street gutter, and then washes into a storm drain, which may at times bypass wastewater treatment (or be in a community that lacks it) and get expelled directly into the ocean.

There are efforts underway to try to clean up the Great Pacific Garbage Patch, thankfully. But I couldn’t get the idea of that trash out of my mind. And so on my next evening walk, I took a leftover grocery bag and my grabber tool with me:


(This isn’t my exact tool but you get the idea.)

And as I walked, I used it to pick up any trash I found on the street and put it in my bag. In half an hour of walking, I filled the bag TWICE! (I was able to dump it halfway through in an actual garbage can.) Again, appalling!

It was also fascinating to see what kind of trash was on the street. Our streets are actually quite clean, with weekly street sweepers coming through. I found the densest concentration of trash when I passed near the middle school :( And by far, overall, the biggest trash constituent was plastics. I collected a paper plate, a crushed soda can, and some napkins, but the huge majority was plastic cups, lids, straws, chip bags, food wrappers, etc. (I also found part of a pair of novelty sunglasses (plastic) and a pencil (not plastic).) In many cases, the items were near to or partly sucked into a storm drain already. The whole time, all I could think of was that mountain of trash in the ocean, and how unnecessary and avoidable it is.

But now, at least, I can tidy up the streets on my way to tidy up the library shelves. :)

Crosswind extravaganza

In April, I got to fly my mom out to Camarillo for lunch. It had been a blustery few days with rather high winds. In fact, the winds were strong enough that on the day before, the previous pilot in N54678 (the plane that I had booked) couldn’t land at our home airport (EMT). I watched his track on Flightaware and saw that after two attempts, he decided to divert to Brackett (POC). (Good call!)

Good call for him, but awkward for me; would I need to drive to POC to get the plane? Nope! He kindly offered to go early to POC the next morning to pick up the plane and return it to EMT for me. He tried to get a ride there with another pilot, but then *her* plane ended up having a failed seat rail! So then she DROVE him to POC and he flew 678 back! I really appreciated the extra effort!

Winds were calm at EMT, but I could see that they were forecast to be stronger at Camarillo (CMA). We took off and did some sightseeing along the way. Our plan was to attempt to land at CMA, but with the understanding that if it wasn’t possible, we would just turn around and cruise back to EMT.

Indeed, the winds did pick up as we headed west. As we got closer, I noticed that my heading and course were deviating by more and more. The wind was coming from the northeast, and the amount of turn required to stay on a westerly course was large enough that there was a distinctly unfamiliar “sideways” element to our motion (visually, with respect to the ground). It was even more noticeable on downwind, when we were closer to the ground. I’d never crabbed on downwind!

From 10 miles out, CMA was reporting winds from 070 (northeast) at 21 knots, gusting to 30 knots. That was the strongest and gustiest wind I’d ever attempted to land in, plus being a mild <= 5-kt crosswind (for runway 8). But I decided to give it a try. As I got closer, the wind was shifting more northerly, which was increasing the crosswind component. On downwind, it was coming from 040 but had died down in strength a bit to 16 knots (gusting to 29). That's a 10-18 knot crosswind, which is hefty for a Cessna 172. But no reason not to try; if I couldn’t maintain runway heading due to too much crosswind, I would go around (or simply depart). In fact, the plane before me did go around (eep?).

The tower cleared me to land and provided a final wind check: winds from 050 at 19 gusting to 29 knots. My heart was beating fast. I figured there was a good chance this would not be a landing, so I was mentally prepared to go around. I turned final and had on my extra 5 knots of airspeed as protection against the gusts, and I was managing to track the runway centerline. I was banked left, into the wind, with full right rudder to keep the nose aligned – a very strong slip! It seemed to take forever for us to get past the threshold and creep down over the runway – not surprising since it was a 16-25 knot headwind, which reduced our groundspeed on final approach from 65 knots to only 40-50 knots. I noticed that my right hand, gripping the throttle and carb heat (ready for go-around) was shaking a little. I think it was adrenaline :) because I didn’t feel scared, just extremely focused. The touchdown was fine. And then I felt a bit of wobbling drift, probably because I relaxed the ailerons (a good lesson on why it is so useful to envision the wind direction even when you’re on the ground!), but I regained directional control quickly. We exited the runway in triumph and taxied to the restaurant.

There was LONG wait for lunch, as is often the case at Camarillo. We passed the time enjoying the cute miniature version of the airport and ogling the windsocks (notice the flags, windsock, and palm trees at right). The forecast was for the winds to die down into the afternoon, so I expected that conditions would be better for our return flight.

After lunch, I got a weather briefing for our flight back to the east. There was a sigmet for moderate turbulence, and the northeast winds were predicted to swing around to the southwest at some point. It’s not often that you get tailwinds both directions! :) Ontario was reporting blowing dust (ick). Winds at EMT, however, were mild. Unfortunately, the winds at CMA had not improved as much as predicted; they were now from 080 (straight down the runway at least) at 18 gusting to 25 knots. Curiously, the winds at Oxnard (just 6 miles away) had changed to 290 at 12 knots, indicating that the front was indeed moving in from the west and we could expect a wind change at any minute.

I taxied out to the departure end of runway 8 and held short. As we sat waiting for a takeoff clearance, the windsock caught my eye. It was indicating wind from the west, NOT from the east – which would be a tailwind if I took off on runway 8. The front was upon us. Just then, the tower cleared us for takeoff. I reported the contradictory windsock to the tower, who responded that the wind sensor and windsock at midfield was still indicating wind from the east. Eerie! Well, I figured that I might as well try to beat the front and, by the time I was rotating for takeoff, I’d probably be into the easterly wind. And if things didn’t look good, I could always abort the takeoff. I had 6000 feet of runway at my disposal.

I took off and immediately encountered a flock of birds about 100 feet off the ground and reported it to the tower. I nosed down to fly under the birds, which made me pick up airspeed, which made my whole takeoff feel non-standard. I noted that the tower was now giving wind reports to other pilots coming in that included “low-level wind shear” as would be expected given the disagreeing windsocks. That’s definitely something to be wary of when coming in to land. But luckily, I was off the ground and climbing away.

Right about then the tower asked me to “report gain or loss midfield?” which I couldn’t process into a coherent question. Me: “Gain or loss of what?” Tower: “Report gain or loss midfield.” Me: “Say again?” Tower: “Frequency change approved, have a safe flight.” (Translation: “We’re done trying to communicate with you.” :) ) As I continued my climb (and switched frequencies), I decided that they were probably asking me if I’d noticed a sudden gain or loss of airspeed/altitude (which could occur if I passed through the front). Due to my evasive maneuvers, I couldn’t say whether the wind alone had affected the plane at that point. It’s probably still good that they warned other pilots of potential wind shear!

The rest of the flight back was uneventful and scenic. When it was time to land at El Monte, the local winds were very light – from 180 at 4 knots. I was very glad that it was so much better than the previous day and that we were not forced to divert. And I got some great crosswind practice and successfully passed that real-world test! (And took away notes for future improvements. There is truly a world of difference between theoretical crosswind compensation and actually doing and feeling it!)

When thunderstorms get in your way

On July 6, I flew myself to Palm Springs. This is a short hour-long flight that takes you just outside of the L.A. basin. It turned out to be a record-breaking hot day across SoCal, so the primary things on my mind were keeping the engine cool enough to function and assessing the impact on airplane performance. Palm Springs is only 476 feet above sea level, but given the forecast high of 118 F (!), the density altitude would be above 4000′! (Here’s a handy density altitude calculator.) That means that the airplane would perform as if it were trying to land/take off from an airport at 4000′ elevation. Definitely something to factor in (faster ground speed on landing, longer landing roll, longer takeoff roll, reduced climb performance, etc.).

During preflight, I discovered that the plane’s landing light wasn’t working. I wouldn’t need it for my outbound flight, which was in the morning, but it would potentially constrain my options for a return flight. I decided to proceed and marked it INOP.

I got flight following to Palm Springs at 5500′. I was keeping a close eye on the engine cylinder head temperatures (CHTs), because it was so hot. To keep these values low enough, I had to throttle back and lower the nose, and I was only able to climb at about 150 fpm. In retrospect, I’m thinking that it might have been wiser to not take the plane out on such a hot day!

Along the way, I saw a fire burning at the Cajon Pass. SoCal ATC was busy calling traffic alerts with lots of mentions of firefighting aircraft, which were taking off from San Bernardino. They were all well north of my path.

When checking NOTAMs before my flight, I learned that PSP had changed their ATIS frequency from 118.25 to 124.65 as of May 31. Curiously, the official airport diagram (updated June 21) still had the old frequency. As I got closer, I checked both frequencies until I came through the Banning Pass and could finally pick it up – and sure enough, it was the new frequency. I was glad I’d gotten the NOTAM! Especially when I tuned in and heard that it was 46 C at PSP. I’ve never before heard an ATIS temp in the 40s!


Final approach to runway 13R at Palm Springs

Palm Springs airport was dazzlingly bright and empty. The tower gave me my choice of runways, so I took the big one, 13R (10,000′ long! Why not?). It has a 3000′ displaced threshold, so it feels like it takes a looooong time to get there on final. :) In my flight planning I’d learned that it’s a common mistake to think that the second dark strip to the left is runway 13L. It’s not! It’s a taxiway. I’m glad to learn from others’ tips this way.

I had a nice landing and then was told to “roll out” to taxiway B at the other end, which also took a long time. In this case, landing long (to end up closer to the exit) seemed like a bad idea since if I needed a go-around, I would want all the runway I could get. I parked and got to enjoy a very nice FBO experience. I even got to cool off with a post-flight swim! First time I’ve visited an FBO with a pool!

For my return flight, things got a little more interesting. I had planned to fly back on the afternoon of July 7. Waiting until the evening would be better, when it would be cooler, but since the landing light was INOP, I had to get back before sunset. On the morning of July 7, I found that thunderstorms were forecast for the afternoon. There was also a big TFR over San Gorgonio, where another fire had started burning. This was also (just) north of my intended route, but it could mean worse visibility due to smoke.

By midafternoon, the METARs were getting hairy, with TS (thunderstorms), LTG (lightning), CB (cumulonimbus), and TCU (towering cumulonimbus). From what I could deduce, a thunderstorm with lightning was raining on Ontario (just north of my path) and cumulonimbus clouds were squatting over March (just south of my path), likely with associated turbulence and up/down drafts that can extend 20-30 miles out, exactly where I would be flying.

These conditions were a clear “do not fly” signal. So I decided to stay an extra night and fly home in the morning, when it would not only be cooler but also be before any afternoon atmospheric drama would develop. Even when rationally you can clearly see that the right decision is to cancel, it still takes (maybe always will take) an effort! But as a bonus, I got to spend more time visiting family, seeing The Incredibles 2, and having a lovely dinner.

The next morning, it was “only” 99 F when I took off. I was assigned runway 13L this time (the short one), which I determined was still long enough (4952′) for my needs. I expected to depart left traffic, but curiously I was told to make right traffic. It felt weird to turn and keep climbing over the departure end of 13R, but I assume there must have been some traffic east of the airport they wanted me to avoid. As I climbed, another plane called in complaining that they couldn’t get the ATIS, and the tower told them about the month-old frequency change. Now I’m wondering if this is a test to see who is actually reading NOTAMs?

The tower asked me to follow highway 111, which leads northwest away from PSP, at or below 3000′. He seemed happy that I knew where this highway was and could comply. Eventually he handed me over to SoCal and thanked me for my “help” (I still don’t know what he was having me avoid, but happy that he seemed happy). I came back through the Banning Pass, slowly climbing to 4500′, and then SoCal asked me to divert north around Ontario’s airspace. I had planned to go south via PDZ, but okay, I obligingly turned north and spent some time fiddling with the GPS to change my flight plan. In retrospect, I think I could have just communicated that I was heading to PDZ and that might have been fine – they probably just wanted to keep me out of the busy part of ONT’s space. But this way I got to fly over the San Bernardino airport (see left).

The rest of the flight was uneventful and I was home in time to quickly pack for a work trip to Sweden the next day!

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