Truck Drivin' Man

Commander Cody - Truck Drivin' Man
Talking to Iaman, who spends a great deal of his time criss-crossing the Southwest U.S.A. in his pick-em up truck, and this tune popped into my head. Commander Cody has been here before.

Rocket Science

Why Do Ion Thusters Use Xenon? KSP Doesn't Teach.....
Since I have been studying chemistry, I've started to take note of specific uses for specific elements. (It helps that Scott uses the word 'specific' in his video.) I mean it's kind of weird. We've got this periodic table of elements and supposedly elements that are adjacent in the chart have some similar properties, but it seems that those similarities are vastly overshadowed by their differences. Which makes the fact that we even have a periodic table pretty fricking amazing.


What is Hall Effect and How Hall Effect Sensors Work
Hall Effect Thruster sounds like something I should understand, after all Hall Effect Sensors are everyday items. Shoot, the ABS in our 1995 Ford Windstar used Hall Effect Sensors for measuring wheel speed. Your keyboard probably uses Hall Effect Sensors to determine when you have pressed a key, assuming of course that you are even using a real keyboard. I dunno how many people are reading this on their smart phones, but what am I gonna do about it? Yell at the kids? Tell them to
'get off of my lawn'? Yeah, like that's gonna work.

Anyway, I didn't really understand the Hall Effect until I watched this video. I also watched another half a dozen videos on the subject and while the audio track on this one isn't Hollywood perfect, the video is still better than all the others I sampled.

The Hall-effect thruster aboard the European Space Agency’s SMART-1 mission. Launched in 2003, this became the first Hall thruster to be utilized beyond geosynchronous orbit. Photo Credit: ESA

The Hall-effect thruster in the above image is from Experimental Design Bureau (EDB) Fakel of Kaliningrad, Russia. That's twice Russia got mentioned today. Three times if you count the link in my post about cocaine production. The link pointed to a story that came from RT (formerly Russia Today).

Scott Manley (the video up top) has appeared here before.

Chemistry

$500,000 of Calcium - Periodic Table of Videos
Diabolical daughter is taking a chemistry class so, naturally, or perversely, depending on your point of view, I am also studying chemistry. One of things we've been working on is determining how many grams of a product you can expect from a chemical reaction of two compounds, given the initial amounts. This involves calculating the molecular weight of the compounds, which means looking up the atomic mass in the periodic table. Since the atomic mass of an atom is simply the number of protons plus the number of neutrons (electrons weigh so little that we don't even bother with them) you might think that the atomic weight would be a nice round integer as well. But that discounts the isotopes: all elements come in multiple flavors. Any bunch of atoms one element will have the same number of protons, but they will have different numbers of neutrons, so individual atoms may have different weights. The atomic weight is the weighted (heh) average of the masses of all the known flavors / isotopes.

This business of electromagnetic separation of isotopes of Calcium is similar to the process the U.S.A. used to separate U-235 from the mass of refined Uranium.

Quote of the Day #2

Coca Plantation

EL TARRA, Columbia - The coca leaf used to make cocaine has made such a dramatic comeback in this country that plantings now cover more territory than they did before a multibillion-dollar U.S.-sponsored campaign began 16 years go, U.S. and Colombian officials said. - Juan Forero writing in The Wall Street Journal (paywall)

The War on Drugs is never going to go away, it is our very own Forever War. There are too many people on both sides of the fight with a vested interest in keeping things the way they are. Rational discussion has no place in an argument dominated by money.

Quote of the Day

     [P]olitical experts aren’t a very diverse group and tend to place a lot of faith in the opinions of other experts and other members of the political establishment. Once a consensus view is established, it tends to reinforce itself until and unless there’s very compelling evidence for the contrary position. Social media, especially Twitter, can amplify the groupthink further. . . .
    Journalists should recalibrate themselves to be more skeptical of the consensus of their peers. That’s because a position that seems to have deep backing from the evidence may really just be a reflection from the echo chamber. You should be looking toward how much evidence there is for a particular position as opposed to how many people hold that position: Having 20 independent pieces of evidence that mostly point in the same direction might indeed reflect a powerful consensus, while having 20 like-minded people citing the same warmed-over evidence is much less powerful. - Nate Silver on FiveThirtyEight.com

Via The Wall Street Journal, which is where I read it. I extracted the same bits I found in the paper.

Charge

Arctic Cat Snowmobile

A couple of weeks ago there was a story in the WSJ about snowmobiles that mentioned some of technical advances that have been made, and one of them was turbochargers. Turbochargers have been around for a while, you can buy a production car right off the showroom floor that is equipped with a turbocharger or even two. Hot rodders have been putting them on all kinds of machines, but as far as I know no one has put a turbocharger on a small, mass production engine, like those found in motorcycles or snowmobiles, until now.

P-38 Turbocharger Installation

Anyway this started me musing on the subject and the turbochargers from the WW2 P-38 fighter aircraft popped into my head, so I went digging, and some strange stuff surfaced.

First of all, almost all WW2 aircraft engines were supercharged, which gave them enough boost that they were able to reach altitudes of 25,000 feet (five miles high). When engines were equipped with turbochargers, the turbochargers were added to the existing supercharger arrangement so the engine now had two stage supercharging. The turbo provided the first stage. This moderately compressed air was fed to the supercharger, which compressed it to the point that is was as dense as the air you find at sea level, and fed it to the engine. This two stage compression gave the aircraft enough power to reach 40,000 feet (eight miles high), more or less.

Shane Christopherson and his General Electric turbocharger

The General Electric turbocharger (it is always referred to as the General Electric turbocharger) was a bit of a beast. It was also secret, kind of like the Norden bombsight or RADAR. Early on in the war, we sent some P-38's to Britain, but for some reason (perhaps because we didn't trust the Brits to be able to keep a secret), they weren't equipped with General Electric turbochargers, which had a sizable impact on their performance. I imagine the Brits weren't too happy about this, but beggars can't be choosers, so they took them anyway.

P-47 engine, turbocharger and associated duct work

The P-47 was also equipped with a General Electric turbocharger. The P-47 always looked a little plump, but I figured the designers knew what they were doing, and who knows what kind of complicated stuff was buried in the fuselage. Well, now I know. It was puffed up to accommodate all the duct work needed to connect the engine in the nose with the turbocharger and intercooler in the tail.


The De Havilland Mosquito
Now I'm watching a YouTube video about the De Haviland Mosquito which seems to have been quite an aircraft. It is a British aircraft, so it was not equipped with a General Electric turbocharger, but it still managed to get to high altitudes. How did it do that without a turbocharger? It had a two-stage supercharger, that's how.

Merlin Two-Stage Supercharger

The two-stage superchargers on the Merlin engine were driven by gears. General Electric turbochargers are driven by exhaust gas from the engine. Gears are dense and compact. The duct work needed to connect the engine to the turbo is bulky, but not dense. The weight penalty is probably similar. Duct work is easy to fabricate out of sheet metal. Gears require machine tools and castings to hold them alignment, which means the drive mechanism for a supercharger is going to be more expensive than the duct work for the turbo. On the other hand, the turbo needs to be made from unobtanium in order to withstand the heat from the exhaust gas. Superchargers can be made from regular old metal like aluminum or even iron, if you don't mind the extra mass. I think it is safe to say that the General Electric turbocharger was the forerunner of the General Electric jet engine program.

Bombing of the Gestapo headquarters in the Shellhus, Copenhagen, Denmark in March 1945. A Mosquito pulling away from its bombing run is visible on the extreme left, centre.

de Haviland Mosquito was an all wood airplane, and it you believe everything in the video, you might conclude that it was vastly superior to all of the big, heavy, four-engined bombers (like the Flying Fortress, the Liberator and the Lancaster) that the Allies used for the majority of their bombing raids on Europe. That superior performance was entirely the result of its high speed (fastest WW2 military aircraft), which it was able to attain because of its light weight. It was light because it didn't carry any armor, or gunners or gun turrets. Originally it did not have any guns at all, but once they found out what it could do, they mounted a bunch of guns in the nose.


Twelve O'Clock High
I suppose it was 12 O'Clock High, and my dad's role as a gunner in a B-24, that locked the heavy bomber into the leading role (in my mind) in our war against the Axis. I remember quite vividly how the Japan's Mitsubishi Zero was a light weight, high-performance aircraft whose Achilles' heel was its lack of armor. What all this illustrates is the 'design by committee' syndrome. When the enemy builds a high performance aircraft without any armor, it's because they are not concerned about their pilot's well being, but when we do it and the aircraft is hugely successful, we shove it under the rug because it doesn't fit the narrative that the military industrial complex is trying to sell us.

There are advantages to this approach. The story is vital in order to garner popular support, which you really need in order to win. And building big, heavy airplanes means you need a big, heavy, industrial machine to produce them. And if push comes to shove, you can drop a lot of weight by getting rid of the armor, which is going to make your aircraft perform better, which is what you really need in combat. It's kind of like sandbagging. You carry a bunch of extra weight around with you which makes you look slow and cumbersome, but it makes you stronger, and when it comes to crunch time, you can drop those sandbags and really drop the hammer on your enemies.

Donald & Hillary

Donald & Hillary, via Getty Images

I hope they will be happy together.