Special Pages

Monday, September 30, 2019

Another 50 Year Anniversary

Depending on which source you go to, 50 years ago this weekend (within plus or minus about five days) The Beatles last studio album, Abbey Road, was released.  The band would break up in 1970, and while another album (“Let it Be”) would be released, that would be based on some tapes that the band had recorded before Abbey Road.  The studio session for John Lennon’s “I Want You (She’s So Heavy)” was the last time that all four members were in the studio together.

Need I say it was one of my favorite albums?

The album was released to mixed reviews (isn't that always the case), but it was big seller.
The Guardian found the record “a slight matter”, although Rolling Stone remarked that it showed that the band was “still unsurpassed”. Commercially, there was no question. It entered the UK charts at number one, where it spent a total of 17 weeks, with similar performance internationally.
...
Their recording swansong followed fragmentary, disparate work on 1968’s White Album and the fractious Get Back sessions in the early months of 1969. That was an attempt to rekindle their early, live energy first in Twickenham film studios and latterly their Apple building on Saville Row although it collapsed into discord, leaving hours of tape that would eventually surface as the 1970 album Let It Be, with Phil Spector tasked with finishing the job.

Work on Abbey Road in summer 1969 wasn’t free of discord but, unlike the preceding Twickenham sessions, it didn’t result in sloppy and incomplete recordings. This was due in no small part to the reinstatement of George Martin as producer and the band’s return to EMI studios. Martin instilled a sense of discipline. His involvement came with the condition that the band “let me produce it the way we used to”.

The band, unable to face returning to the Get Back tapes – “none of us would go near them”, remarked Lennon – concurred. As Harrison would recall: “We decided, ‘Let’s make a good album again’.”

It’s plausible that, sensing the end was near, they wanted to go out on a high. The extent to which Abbey Road was planned as a finale is debatable. As with much of the Beatles’ final days, matters are shrouded in contradiction. The mix of schoolboy friendships, working relationships, a strained legal partnership and creative inspiration meant that the months of recording were unlikely to be either unremitting contention or unbroken harmony. It’s also almost impossible to discount hindsight and the tendency to read their final moments as a band into the music – “The End” ’s elegiac conclusion to the medley on side two in particular.
As I got older, I came to think of that “side two” as one continuous song, rather than the nine separate titles listed on the jacket and prefer to listen to it that way.  Some of the reissues of the album appear to treat it that way.

The iconic cover photo of the group outside the studio has been copied and parodied an incredible number of times.


I actually have this one as a framed 8x10 on the wall, not the real one.


Naturally, there are 50th Anniversary Special Editions out at your favorite streaming service or however you buy music these days.  I haven't bought any of them and probably won't.  I have the CD version of the album that was remastered in the 90s (I think!) and having a new group of producers recreate the music is like asking someone to recreate the Mona Lisa or Michelangelo's Pieta.  They're more likely to screw the pooch than produce a masterpiece from the old tapes. 
...and in the end,
the love you take
is equal to the love you make


Sunday, September 29, 2019

The SpaceX Starship Announcements

Personally, I only watched the short version.  I had been intending to watch the whole thing live last night, then got distracted by putting together my post.  When I remembered and switched to YouTube, it had been going for over an hour.  Use this link if the embed doesn't work.


If you want the full thing, 1 hour, 25 minutes, use this link.

Having the presentation on Saturday puzzled me a little, but Elon explains why this date was chosen in the first couple of minutes.  This is the 11th anniversary of the first orbital flight by SpaceX.  As he says, if they hadn't succeeded, it would have been the end of SpaceX.  Shut the doors and go home.

Just to be clear about what we're talking about:


Saturn V, Starship, and Falcon 9.

Saturday, September 28, 2019

Ham Station is Halfway Restored

I've written a few times about recovering from our lightning strike.  The majority of the work in the ham shack was covered in my Post-Mortem piece from the 3rd of the month.

It has taken me a while to get here, but I got the antennas fully working and back up today.  I ended up replacing most of the cabling, replaced my antenna rotator and its cable, rebuilt the balun transformer on the HF antenna and did essentially the same thing to the VHF antenna by replacing it's cabling and feed wiring.


Today's plot of the SWR (red), Magnitude (green) and angle (purple) of the antenna impedance.  The 6 meter ham band, 50 - 54 MHz, is included in the area shaded purple, which appears to be 49.5 - 54.5 MHz.

When I last posted about trying to fix the amplifier, I mentioned a couple of panel mounted 20A breakers, one of which needed to be replaced.  Those parts came in and I mounted them last weekend.  The little tag I had put on one pair of wires managed to fall off, so given four wires, I got it wrong and wired one of the breakers directly across the 240 VAC line.  That tripped the house's circuit breaker, not the one in the amplifier.  Once I cleared that and re-wired the breakers, the breakers were fine but it now blew the same two fuses I showed in that last post and I repeat here.


I don't have much in the way of circuit details, which is complicating fixing this, but I can see the input to those fuses goes two places.  First, some of the AC is used on the printed circuit board the fuses are mounted to.  Second, and you can see it quite clearly in that photo, there are two wires (blue on the left, brown on the right) that come onto the board, go through the fuses, and then go to another board.  That board is a power supply that other people have reported problems with.

Figuring if I disconnected half the places the 240 VAC goes, that will tell me which half blows the fuses, I disconnected the blue and brown wires to the other board.  Plugged it in and the fuses are fine.  Now I need to try to troubleshoot the board that blows the fuses.  It looks fairly normal with no AC applied. 

Getting my antennas back operational was a priority for me because now the station is fully usable.  It doesn't have all the capabilities it had before the lightning strike, but I can operate any amateur band from 3.50 MHz through 450 MHz.  The amplifier is really pretty low priority.  Of all the things I'd consider important to the operating I want to do, the amplifier is pretty much the bottom of the list.


Friday, September 27, 2019

Game Theory and Gun Laws

Borepatch had an article yesterday arguing that we need to invoke game theory in dealing with gun control forces.  He starts with a premise every gun rights person knows and then briefly invokes Game Theory, a branch of mathematics that studies interactions between rational decision-makers as found in games, describes the interactions mathematically and attempts to find optimal solutions where possible. 
Notice how whenever there's a shooting by some lunatic that we're inundated by calls for new gun control laws restricting normal Americans?  Every.  Single.  Time.

This happens because there's no downside for the Democrats.  Game Theory tells us that in situations like this (where one side is motivated to a goal and the other side passively watches what happens) that the motivated side will ultimately prevail.  Game Theory also tells us that a "tit-for-tat" strategy of pushback - a pushback for each time the other side pushes - will result in a stable outcome.
From here, Borepatch goes into Common Sense Abortion Control as where we push back.  For example, he describes the news in the last few days of the abortion doctor who died and left behind over 2200 trophy aborted fetuses in his garage.   Taking the Gun Control approach, we could argue we need extensive registration and inspection of all abortion facilities to prevent a recurrence of this sort "trophy harvesting".

For another example, he brings up the problem of children who are supposed to be aborted but survive.  Last year, there was weekly outrage (with no results) when Governor Ralph Northam of Virginia advocated for infanticide.
Again, taking the Gun Control approach, we need to require that all abortions be performed at a Hospital where care is available for babies in this situation.  Sure it will massively raise the cost of abortion, but you can't make an omelet without breaking a few eggs, amirite?
It turns out Borepatch isn't the only person advocating for use of Game Theory - or, at least, a view based upon the subject.  Open Source Defense posts a long and worthwhile examination of the Universal Background Checks arguments.  He starts with the observation that UBCs really do poll at 90% support, if the pollster simply asks, “Would you favor or oppose background checks on all potential gun buyers?”  Given that level of support, why haven't they already become law?

If you're in the culture, you probably already know the answer.  When people are told what UBCs really entail, support drops radically.  There have been actual ballots on these things.
UBCs were defeated in Maine, and passed by less than 1% in Nevada.  UBCs passed with 59% in Washington, a state that hasn’t elected a Republican senator since 1994 or a Republican governor since 1980. UBCs were rejected by Congress in the 1993 Brady Bill, specifically as a compromise to get the bill to pass — and the early ’90s were a high-water mark for support for gun control.
Earlier this year, the House passed a bill called HR8 on a party line vote by the Evil Party majority.  While called a Universal Background Check bill, HR8 (like most such legislation) redefines a transfer from being a permanent sale of a gun to simply loaning one to someone or letting them touch the gun.  David Kopel at the Volokh Conspiracy did an epic analysis of HR8.

Empirically, we have evidence that UBCs are popular where guns are culturally irrelevant, unpopular where guns are culturally relevant, and never the twain shall meet.  Why does each side insist on a path that the other side genuinely believes is insane? Why does each side only try to win by force?

Here's where the author, Kareem Shaya, goes into game theory.
The problem is that the two sides are in Nash equilibrium: “a strategy profile is a Nash equilibrium if no player can do better by unilaterally changing his or her strategy”. If you want to spread gun rights, would making a unilateral concession to the gun control crowd help you spread gun rights? If you want more gun control, would supporting an advancement for gun rights help you get more gun control? Obviously not, in both cases. In Nash equilibrium, a unilateral concession would by definition only hurt you. So in that sense, of course both sides are trying to cram victory down the other side’s throat. Mathemetically, a unilateral compromise can only open the door to more concessions.
An important part of this situation (as can be seen in the gun control lobby) is that if you're in Nash equilibrium, you have no incentive to change your strategy; that's another way of saying a Nash equilibrium is a stalemate.  It's where we are now.  As Shaya notes (and as we all have):
This is where people use the word “compromise”. But on guns, what they usually mean is, “Fine, let’s compromise: we’ll do none of what you want and only half of what I want.” Gun owners know the game theory well enough by now that they can never allow another unilateral loss. (You know how well they know it? If I just say “cake meme”, they all know what I’m talking about.) Gun control groups are in the same boat incentive-wise, and so can never sign onto a reform of existing gun laws.
Given the stalemate of Nash Equilibrium, nothing is going to change.  The gun control side isn't going to give up anything to the gun rights side that they think they've won through hard work and the gun rights side has no reason to believe offers to "compromise."  Therefore, we need to change things up to gain rights back; as if that ever happens.  Will Borepatch's idea gain anything for gun rights?  Hell if I know.

Kareem Shaya has this to say on the Nash Equilibrium:
There is an outside chance that given the right emergency, a one-sided law could pass by force. But that could — for these same game theoretic reasons — set off a chain-reaction of backlash that gets arbitrarily bad. Like anywhere from Waco bad to civil war bad.


Wednesday, September 25, 2019

Not a Red Flag Seizure But A Swatting

In Broward County, city of Weston, the wife of a city commissioner filed a police report after a resident of the city named Peter Van Antwerpen posted a meme to a Facebook group.  The meme consisted of a reference to a draft law that appears to be in line for consideration in our state's next legislative session.  The session is looking bad for gun rights in Florida after the way the Stupid Party sold out last year.  While the session starts in mid-January of '20, word of preliminary hearings and activities are coming out now.

The law in question appears to be senate bill SB 134, which repeals the state preemption law and allows political subdivisions and municipalities to pass firearm laws more restrictive than state laws and potentially pass their own gun control ordinances.

The state preemption law this is about is something we picked up in the last few years.  Ten years ago when I got my Florida CWFL, preemption was the law, but there was no enforcement - no consequences for breaking it.  The reality was while state law might have said it was legal for one to carry their concealed weapon in a county park, the county could say no.  The current preemption law added enforcement and individual liability, punishing the county legislators who passed the law violating the state law.
Van Antwerpen posted a meme of Charleston Heston holding up a rifle with the caption “from my cold dead hands.” The picture and quote originate from the 2000 NRA convention where Heston gave an impassioned speech about gun rights.

In the social media post by Van Antwerpen a few anti-gun politicians were named. Van Antwerpen wondered if the gun banning politicians were going to lead the confiscation effort in person. Nowhere in his post were any threats issued.
....
Van Antwerpen is also a well-known philanthropist in the community. He is involved in local politics fighting against liberal corruption. The semi-retired executive is a strong believer in the second amendment and the Constitution.

Beth Jaffe, who is the wife of city commissioner Bryon Jaffe, felt that the meme was threatening her life. Ms. Jaffe contacted the district office of the Broward County Sheriff's Department and asked for them to investigate Van Antwerpen.
Remember, this is the same Broward County Sheriff's Department formerly (and potentially to be again) run by Chief Coward Scott Israel, and the home of the Broward Coward School Resource Officer who ran and hid during the Parkland shooting.  They're not known for blistering competence.

The SWAT team showed up banging at Van Antwerpen's door in the early morning, in full tactical gear, without any warrants.

As SWATTINGs can work out, it ended well.  I'm guessing that's probably because of his being "a well-known philanthropist in the community."
Van Antwerpen, in a bath towel, greeted the members of the unit. The investigator's started to question Van Antwerpen about the social media post. He is a major supporter of law enforcement, so he chose to answer their questions.

Van Antwerpen explained the meme and asked the lead investigator if the meme broke any laws. The Sheriff's Deputy admitted that it did not break any laws. The investigator concluded that Van Antwerpen was not a danger to anyone. He gave Van Antwerpen the police report number.
This being the Broward County Sheriff's Department, it took them three weeks to deliver the report to Van Antwerpen.  That's when he found the complainant was Beth Jaffe, the wife of Weston city commissioner Bryon Jaffe.  There's a history of "bad blood" between the leftist Jaffes and the more freedom-oriented Van Antwerpens.  Peter Van Antwerpen took to Facebook to highlight what he sees as a personal vendetta against his family.
“A city commission member's wife, Beth Jaffe, who has a well known antipathy for my wife, myself and my family, sent an email to the threat assessment division of Broward Sheriffs Office and over a week later BSO deputies in full tactical gear showed up at our house to interrogate us on this post,” Van Antwerpen wrote on Facebook.
Because the article source (Ammoland News) doesn't mention Peter Van Antwerpen owning guns and having them removed, this doesn't appear to be a Red Flag law misapplied, but it's clearly a SWATTING (although Ammoland strangely doesn't call it that directly).  It's yet another example of unreasonable search in violation of the 4th amendment (the SWAT team had no warrants).  Still, it could have gone much worse and might have if Mr. Van Antwerpen wasn't well known in the city.  Nuisance SWATTING should be a crime. 


Weston City Hall (source)



Tuesday, September 24, 2019

Lamborghini Moves Supercapacitors Into the Hybrid Car World

Italian high-end carmaker Lamborghini has announced a small production of their very high end "mild hybrid" car that moves supercapacitors into the role batteries usually hold.

First, a few definitions.  A mild hybrid, as opposed to full hybrid, is one that uses either a smaller electric motor, or uses it for a smaller portion of the car's power.   A supercapacitor is a capacitor with exceptionally large capacity.  The capacitors you usually encounter in a computer or radio might range from trillionths of a farad (the unit of capacitance) up to hundreds of millionths of a farad. Supercapacitors have a million times larger capacitance than those "hundreds of microfarards" capacitors, up to hundreds or thousands of farads.

Now, it's a little questionable that the Lamborghini Sián (pronounced “Shaan”) sports car is mild in any sense of the word.  First off, it's equipped with a drive train that combines a massive V12 rated at 785 hp with the additional 34 hp from the hybrid system, giving the Sián a total of 819 hp, and enabling it to reach a top speed of over 350 km/h.  Secondly, there will only be a production run of 63 Siáns made and they’re all accounted for—at a cost that’s rumored to be $3.6 million.  Each. 

The novelty of the car is the supercapacitors.  Capacitors and batteries are very similar in the way they're built and their schematic symbols reflect that.  Capacitors are parallel plates of conductors separated by a dielectric, and in "large value" capacitors the dielectric layers have electrolytes in them.  In batteries, like the lead acid battery that start most of our cars, there are parallel plates of lead in a bath of sulfuric acid electrolyte surrounding the plates.  The Sián substitutes an array of supercapacitors for the more familiar lithium ion battery pack in the hybrids we've seen from other manufacturers.
While Li-ion batteries can store around 20 times more energy for their weight than supercapacitors, the battery’s flaw is that it takes time to discharge this energy due to resistance within the device. The fast movement of charge in supercapacitors is due to very low internal electrical resistance. In effect, this means they can be charged and discharged at high specific current values (A/kg) that may be over 100 times that of batteries, without damaging the unit.

Consequently, while a regular battery can handle around 2,000 to 3,000 charge and discharge cycles, supercapacitors can ideally last across millions of charge-discharge cycles without performance degradation. That’s because no physical or chemical changes occur when a charge is stored within them.

On the other hand, capacitors don’t have the energy storage density of batteries. Therefore, they don’t store nearly as much power as a battery of the same physical size.

As developed for the Sián, the supercapacitor array is said to be three times lighter than a battery producing the same power. The electric system with the supercapacitor and e-motor weighs only 34 kg, thus delivering a weight-to-power ratio of 1.0 kg/hp. A symmetric power flow ensures the same efficiency in both charging and discharging cycles. Located in the bulkhead between the cockpit and engine, it also enables a favorable overall vehicle weight distribution.
Because supercapacitors can be charged so much easier than batteries, Lamborghini adds another feature that we see talked about (and, to be fair, is present in some electric vehicles) regenerative braking. Regenerative braking is a technology that recaptures the kinetic energy lost as heat when a car decelerates and turns it into electricity.
Thanks to the behavior of the supercapacitor, which contrary to normal Li-Ion batteries can be charged and discharged with the same power, the Sián’s energy-storage system is fully charged every time the vehicle brakes.

...The energy stored provides an instantly available power boost, allowing the driver to draw immediately on increased torque when accelerating away, up to 130 km/h (81 mph) when the e-motor automatically disconnects. As a result, it’s more than 10% faster than a car without this system.

The electrical energy system in the Sián is small to save weight (batteries are heavier than capacitors) and it's designed for power-assist scenarios rather than as a full-on hybrid power plant. It delivers rapid acceleration in low gears, with improved traction force provided by the combination of the V12 engine and the hybrid system. Traction force is said to be improved by up to 10% in third gear and the 30 to 60 km/h acceleration time is improved by 0.2 seconds compared to the company’s Aventador SVJ.

In higher gears and lower speeds, the electric motor increases traction force by up to 20%, reducing the 70 to 120 km/h acceleration by 1.2 seconds, again compared to the Aventador SVJ. This makes the Sián the fastest-accelerating Lamborghini ever, achieving 0 to 100 km/h in less than 2.8 seconds. [0 to 100km/h translates to 0 to 62 mph]
Interesting car for a very well-to-do clientele, but that's Lamborghini's forte'.  It will be interesting to see how the supercapacitors fare in practice, in real cars driven on real roads.  Preferrably in places like the Italian Alps or Dolomites. 


The Sián.

Monday, September 23, 2019

Fixing to Get Interesting Around Here - Space Wise

Private space companies SpaceX and Blue Origins, both with large facilities within 40 miles of where I sit, are stepping up activities on the Space Coast, one of which will probably be tested before the end of the year.

NASA Spaceflight.com reports that Blue Origin, who has made a lot of progress in their design work but has not embraced launching as a business yet, has begun expansion of their facilities on the Cape Canaveral Air Force Station properties.  Blue Origin signed a long term lease for (former) launch complex 36, originally developed for the Atlas Centaur program in the '60s and is building several key pieces of infrastructure on the site.  The complex had its first launch on May 18, 1962, and was deactivated in 2005.

Blue Origin has started construction on their Horizontal Integration Facility (HIF) southwest of the launch pad. The HIF will be used to integrate and process New Glenn rockets before they are rolled out to the pad.  North of the pad, Blue is building a static test facility for testing their BE-4 engines (in its methane and BE-3U hydrogen burning versions) and appears to be being built to house two test stands.  Finally, the pad itself is already under construction in the center of all this.  The pad resembles the larger structures of LC39, where Apollo and STS (space shuttles) launched.  LC39 is now under long term lease to SpaceX.


In this Blue Origin rendering, North is on the right and we're looking west; the Atlantic is close behind this viewpoint.  The HIF is the low slung building on the left, the static test stand on the right, and various tanks for propellant and oxygen add to the landscape.
New Glenn vehicles will be built inside Blue’s dedicated factory at Exploration Park, near Kennedy Space Center. The factory was completed in 2017 and was outfitted with machinery to assemble most of the major elements of New Glenn. These include the stage tanks, fairing halves, and payload adapters – but not the engines. Officials from Blue Origin have confirmed that parts of the first New Glenn are currently being built inside the factory.

Work has started on a New Glenn refurbishment facility next door to the factory at Exploration Park. Few details have been released, but it is known that the new building will be used to refurbish and test recovered New Glenn first stages. According to Blue, each first stage will be rated for at least 25 flights.
Blue origin is building more facilities elsewhere in the US.  Since the United Launch Alliance team chose the BE-4 engines for their Vulcan booster, the demand is up.  Early BE-4 engines are being built at Blue’s headquarters in Kent, Washington, and tested at Blue Origin’s West Texas facility.
In order to meet the coming demand for the BE-4, Blue has begun construction of a $200 million factory in Huntsville, Alabama. The company broke ground in January of this year and has progressed quickly with its construction.
All that said, the tentative date for Blue Origin launches from the refurbished LC-36 is two years out, in 2021.  



Meanwhile, SpaceX appears nearing the first test flight of its Starship. The Starship and its Raptor engines have been tested for short duration start and stop tests several times.  In the most recent test, they lifted the test vehicle about 450 feet, translated laterally to a new landing position and then performed a controlled landing. We learn today that construction of the Starship is proceeding at the company's Boca Chica, Texas, facility.

The test vehicle, officially called the Starhopper (and nicknamed the Flying Water Tower), at 60' tall is a miniature version of Starship at 180' and pictured here (source), which will be the second stage of the monster booster SpaceX is planning called the BFR (Big Falcon Rocket).  The stacked BFR/Starship configuration will be taller than the Saturn V and is intended for moon and Mars missions.


Interestingly, they appear to be building out this vehicle working 24/7:
SpaceX installed both of Starship Mk1’s aft wings/flaps over a 48 hour period, wrapping up the basic mechanical integration on September 22nd. Work has started on the prototype’s raceway and the frames of the first two wing hinge covers were spotted on Friday. As of midnight local time on September 23rd, SpaceX technicians were welding propellant feed lines to the outside of Starship’s tank section and installing the rocket’s header tanks – small secondary propellant tanks – inside its pointed nose section.
Elon Musk will be doing a presentation on Starship this coming Saturday, September 28th, although I can't find details on how it will be available.  Hopefully YouTube live rather than Twitter or Facebook streaming so I can watch it.  Recent reports (rumors?) are that SpaceX is planning a suborbital test of the Starship by itself within the month of October.  According to that Tech Crunch piece, they've filed requests with the FCC for a test to 74,000 feet altitude.  No, there doesn't appear to be a tentative date for the BFR to fly.

We've also heard the next test of the Crew Dragon Launch Abort System will be "any day now" with October to early November being cited often, so after a fairly long launch lull around here, things might be picking up.



Sunday, September 22, 2019

Pass This On If You Do Social Media

Just doing my part.  Anthony Watts, owner and HMFWBIC at Watts Up With That offers "the best pushback to the misinformation of @GretaThunberg you’ll find".  I'd have said the best graph, but that's just me. 
This is one of those “share the hell out of this on Facebook and Twitter” type posts, because it carries a clear and simple message: Greta has no idea what she is talking about.
The kid said, "even at 1 degree of warming we are seeing an unacceptable loss of life and livelihoods."  Sorry, the record of the last century has been an enormous decrease in loss of life due to weather-related catastrophes. 


The graph is by Bjorn Lomberg. The data is from (as it says) the International Disaster Database.

Greta is pretty much a useful idiot in this circus - as are all the kids involved in the protests.  When they're dragging out kids as young as elementary school, you know it's all for show; all for tugging at the adults' hearts.  As a 16 year-old (autistic to boot), Greta's brain isn't capable of understanding the data; she just goes on what she's being told.  The people pushing this agenda are the truly despicable people - scaring children over nothing.  Did anyone in media notice that China prohibited the protests?  China and India get a total pass. 


Saturday, September 21, 2019

Today's Fun Fact

What's the life of a rifle barrel?  About five seconds.  I probably thought the same things you're thinking, so keep reading.

This comes from an article posted to Midsouth Shooters Supply's daily emails from author Glen Zediker.  Glenn is credited as follows:
The preceding is a specially-adapted excerpt from Glen’s book Top-Grade Ammo. Available HERE at Midsouth Shooters Supply. Visit ZedikerPublishing.com for more information on the book itself, and also free article downloads.
The five seconds comes from the total time the barrel is exposed to the hottest gases from the cartridge being fired and the life shouldn't be stated as 5.00 seconds; it's more like 4-6 seconds.  In principle, you could multiply the number of rounds you shot times the amount of time they're damaging the barrel (if you could know that!) and derive the barrel's life.  According to Zediker, barrel wear largely comes from throat erosion from being torched by the cartridge.
Wear in a barrel is virtually all due to throat erosion. The throat is the area in a barrel that extends from the case neck area in the chamber to maybe 4 inches farther forward. Erosion is the result of flame-cutting, which is hot gas from propellant consumption eating into the surface of the barrel steel. Same as a torch. There is very little wear caused from passage of the bullet through the bore, from the “sides” of the bullet, from friction or abrasion. The eroding flame cutting is at or near the base of the bullet.
There's a lot of mythology in shooting, and some of it centers on wearing out barrels.  On one hand, it makes sense.  If some guy hears from a buddy that cleaning his rifle with a combination of raccoon menstrual fluid and Dexron automatic transmission fluid will help his barrel live longer, it's hard for him to evaluate that.  To do a real test, he'd have to test few barrels with different cleaning solutions but keeping everything else as close to identical as possible.  Take the handful of barrels to the range every trip, put the same number of rounds of the same load ammunition through the bunch, and so on.  People generally find something that works for them and stick with it.  If a trusted friend tells you some magic mix worked for them, it's reasonable to just use it.  There are so many variables that affect a long range shot that you simply don't have the time to experiment with all of them.

As a result we get things like “Is it true that using 110 gr. vs. a 150 gr. .308 bullet will extend barrel life because of its reduced bore contact?” and while the explanation is completely wrong, the lighter bullet will give better barrel life.  Not because of reduced bore contact, but because the lighter bullet accelerates faster and that reduces the time the flame cuts into the barrel.

The area a bullet contacts on the barrel has an effect, but because it relates to acceleration — greater area, more drag, slower to move.  Barrel twist also has an effect, but for the same reason — it takes longer for the bullet to spin up and get out of there if the twist is too high.  Yes, those black, "moly coated" lubricated bullets had lower friction and got out of the barrel faster, leading to less burning.
There are bullet design factors that influence erosion. A steady diet of flat-base bullets will extend barrel life. There’s been a belief for years and years that boat-tail bullets increase the rate of erosion because of the way the angled area deflects-directs the flame. And that is true! However, it’s not a reason not to use boat-tails, just a statement. We use boat-tails because they fly better on down the pike, and, ultimately that’s a welcome trade for a few less rounds. An odd and uncommon, but available, design, the “rebated boat-tail” sort of splits the difference and will, indeed, shoot better longer (they also tend to shoot better after a barrel throat is near the end of its life).
What about the common discussion about stainless vs. chromoly steel barrels in an AR?   Zediker's opinion is:
Stainless steel barrels will, yes, shoot their best for more rounds, but, chromemoly [sic] will shoot better for an overall longer time. Lemmeesplain: the difference is in the nature of the flame cutting effect on these two steels. Stainless tends to form cracks, looking like a dried up lakebed, while chromemoly tends to just get rough, like sandpaper. The cracks provide a little smoother surface for the bullet to run on (until they turn into something tantamount to a cheese grater). The thing is that when stainless stops shooting well it stops just like that. So, stainless will go another 10 to 15 percent more x-ring rounds, but chromemoly is liable to stay in the 10-ring at least that much longer than stainless steel.
 

It's an interesting article.  Competition and especially NRA High Power competition shooters have probably heard some of this, but I'm betting it was scattered around in several places.  Likewise Precision Rifle competitors.  I obviously haven't covered everything, so if it sounds interesting to you, go read


Friday, September 20, 2019

Webster Update #5

While waiting on circuit breakers for my radio troubleshooting, I returned to the flywheel saga I mentioned in Update #4 and last Saturday.  It's now finished. 


Once I saw this picture in the camera, I saw a face in the flywheel and now I can't unsee it. 


Now I call the flywheel Mr. Bill.  Mr. Bill's nose (the flywheel's, not the puppet's) is drilled through for the 5/16" crankshaft and the end is reamed to 0.500" diameter by 3/16 deep.  This was my first puzzlement of the last week or so.  I ordered the gears specified in the prints and thought I just used them as provided.  Wrong.  The gear is very different in size from the drawing I have.


The answer was that I needed to machine the gear's hub to meet the dimensions on this print.  Note the upper right says this is a "light press fit into flywheel".  I accomplished that today.  I drilled and tapped the hub for a #6-32 setscrew, used that to fasten the gear to a little scrap of shaft, and used that shaft to hold the gear in the lathe's chuck so I could reduce it to size.  It's now done.


I think the inner web of the flywheel will get painted like I saw on another guy's model.  Flat black wrinkle paint.  I'm set up to do powder coating, so I found a paint I could use. 

I also made a brain dead simple part - the crankshaft itself.  This just needed to be cut to length, so a quick cut on the bandsaw followed by facing and cleaning up the ends on the lathe.  It will get hard soldered (brazed) into a piece that I have yet to make - or yet to decide on how it should look.  The drawing looks like this and I'm focusing on the rectangular tab seen in all three views here:


A couple of builds I've been seen change that little rectangular 1-1/4 x 1/2 tab turns into a rather intricate piece designed to better balance while the engine is running.  One divides that tab at the center of the big hole, and replaces the bottom with a semicircle about 1" radius.  The other replaces the tab entirely, with a sector of a triangular wedge, heavier below the center of the big hole, and tapering to about that half inch dimension of the rectangular piece. 

Not including this part, which is either a simple hour or so, but maybe a full day for the fancy part, I've completed four pages of parts for this engine.  There are 13 pages of parts; nine more.  Not all of them need to be made; so as a rough guess, I've made about a third of the parts.  Most of the rest are smallish parts (like the parts of this crankshaft).  The biggest part left is the piston, so I think that will be my next task. 



Thursday, September 19, 2019

60 Years Ago - The X-15 First Flew

I missed the 60th anniversary of the first X-15 flight on September 17, 1959 thanks to my sources being late on it.  On that day, pilot Scott Crossfield made the first powered flight of the rocket-powered X-15 aircraft, taking it up to 52,000 feet.  The X-15 would go on to fly into space more than a dozen times.  It wasn't the first rocket plane and it wasn't the last, but it was a remarkable test platform for learning more about space, getting sensors working, figuring out reentry, and more.  More than half a century later, the exceptional plane still holds the world record for speed by a piloted, powered aircraft after William Knight flew the vehicle at Mach 6.70 in 1967.


The X-15 had an exclusive group of pilots, but it only numbers a dozen.  Neil Armstrong flew seven X-15 missions between 1960 and 1962 before going to NASA.  Another astronaut, Joe Engle is the last surviving X-15 pilot.  Ars Technica posts a long interview with Joe about flying the X-15, "What it was like to fly the baddest airplane the world has ever known."  Engle says, “The X-15 was the most demanding airplane I’ve ever flown."
On the night before a flight, technicians would mate the X-15 to the B-52 aircraft, pressurizing the plane’s fuel tanks and preparing it for flight. As the pilot, Engle would arrive shortly after sunrise to don a pressure suit and ensure the integrity of its seals. About 45 minutes before the carrier aircraft took off, he would climb into the X-15 cockpit and connect to life support.

Then, the wheels would roll, and the B-52 would take off for its bumpy ride up to the launch location and an altitude of 13.7km. This would take a little more than an hour, during which time Engle would continue to review his cue cards. In particular, he would memorize the various dry lake beds he could make for, were there an engine failure aboard the X-15, based on how many seconds the engine had burned before failing. During the rare moments of reflection at this time, he doesn’t recall being nervous. Rather, he said, “You’re thrilled to death to have the opportunity to be there.”

At the drop-off point, Engle would hit the launch button to release the X-15 from its carrier aircraft. As soon as the rocket plane was clear of the B-52, the pilot would grab the throttle as quickly as possible to open the propellant lines.

The liquid-fueled XLR99-RM-2 rocket engine, built by Reaction Motors, had 70,400 pounds of thrust. This was a powerful engine six decades ago, and even today it has about two-thirds of the thrust that Blue Origin’s New Shepard rocket uses to send a six-person capsule into space.
The X-15 weighed about 30,000 pounds fully fueled and loaded, so feeling over twice its weight in thrust and about 2Gs pushing you into the seat left no doubt that the engine had started.  Still, Engle says it didn’t keep you from reaching up and turning off switches, or maneuvering the airplane with the stick.  As the fuel burned for the next roughly 90 seconds, and the vehicle lost that fuel weight, the G forces increased to closer to 4Gs making it harder to reach the panel.
This initial part of the flight required absolute attention, because any course corrections had to be made early, before the X-15 climbed out of the lower atmosphere. Once on a ballistic trajectory, there wasn’t much that could be done to alter the flight.

For high-altitude flights, the X-15 would have about two to four minutes above the bulk of the Earth’s atmosphere in space. “The first time, I naively thought there would be a lot of time,” Engle said. “I thought I would be enjoying the view out the window.” But reaching space brought a new series of tests. Guidance and navigation engineers wanted ultraviolet and infrared sensors on the plane to gather data about the atmosphere, so the X-15 needed to be rolled 90 degrees one way, back to zero pitch, and then rolled 90 degrees in the opposite direction to sweep the instruments over the horizon at different Sun angles. Some of this data was used to better control the flight of intercontinental ballistic missiles.
...
“The X-15 was the most demanding airplane I’ve ever flown, and also the most rewarding airplane I’ve ever flown,” Engle said. “You’d work your tail off during that 10 minute flight. You’d be covered in sweat. But once it stopped, you really felt like you’d accomplished something, like you’d scored a goal with a USA uniform on at the Olympics.”
The article is definitely worth your time to read.  It's more about Joe Engle and his life than just about the X-15.  After his first flight in 1963, Engle would go on to fly a total of 16 missions over the course of two years, reaching a maximum of 85.5km, above the US Air Force’s threshold to be considered an “astronaut.” He also achieved a top velocity of Mach 5.71.

After those two years, Engle applied to NASA to be an Apollo astronaut, but it was not to be.  Deke Slayton, who appointed crews for the Apollo missions, assigned Engle to be the Lunar Module pilot for the final mission, Apollo 17.  That was overruled by NASA management, who instead wanted geologist Harrison Schmidt on the mission. 
“It was very disappointing,” he said. “I was crushed to learn that. However, going to the Moon was really all about geology. Learning where the Moon came from, and about the craters there. Jack Schmitt had a degree in field geology. To me, it just made sense that he should be on the Moon picking up rocks. So I understood the decision, even if it wasn’t my idea.”
For accepting being dropped well, "being a team player", Engle was given his choice of next mission: would he go for likely orbital Apollo mission or hold out for the eventual Space Shuttles?  He chose the latter and ended up commanding the second spaceflight of shuttle Columbia, in 1981, as well as another mission in 1985.


Joe Engle at a screening of the Neil Armstrong biopic, "First Man", at the National Air and Space Museum in October 2018.  NASA Photo.


Wednesday, September 18, 2019

Fed Cuts Interest Rates; Trump Attacks Them

The Fed Open Market Committee today announced lowering their benchmark overnight lending rate by 0.25% to a range of 1.75% to 2.00%, as was widely expected.  This officially marks the return of "easy money", with the Real Funds Rate going below the "Long Run Neutral" rate:


President Trump, who has been arguing the Fed's policies are unfair to him, was quick to attack
President Trump has been vocal about his criticism about the way Federal Reserve Chairman Jerome Powell has doled out little-to-no interest rate cuts, and he was quick to complain again on Wednesday after the Fed announced a rate cut half of what markets were hoping for.

“No ‘guts,’ no sense, no vision,” Trump tweeted after the announcement.


This is the problem with a centrally managed economy, like the we get with the Federal Reserve Bank.  When the economic growth they measure slows down, they go to easy money, but when it's growing they need to crank some of that extra money they created back in and raise rates.  If rates are already effectively zero, there's no room to lower them if they need to.  The economy is in good shape now, so their tendency was to raise rates.  

It is unfair to Trump that the Fed dumped trillions of dollars of economic stimulus into the economy from 2008 through 2016 helping Obama but now not helping Trump.  That unfairness isn't because of anything about Trump; it's what the Fed has to do to function properly. 

David Asman, co-anchor of  Fox Business channel's program “Bulls & Bears,” made this observation:
“He’s worried that with Europe and Japan issues $16 trillion worth of negative interest rate bonds, our rates have to come down more to make our exports more competitive,” Asman said. “He’s got a point that the Fed has an important role in maintaining the dollar’s parity against foreign currencies.”
He has a point about negative interest rate bonds being issued widely around the world.  When bond buyers would rather lose money by buying a bond than stick the money in a vault, it means they consider losing money on the bond to be the best thing they can do with that that money.  For individuals, the choice is to buy a bond or some instrument that guarantees you will lose money or put your cash in your safe, your mattress, or in a waterproofed pipe in your back yard.  Which is the least risky option?  None of the above, buy silver coins?   

We live in exceptionally unusual financial times, historically speaking.  The world seems on the precipice of something. 


Tuesday, September 17, 2019

Quote of the Day - Florida and California

From the Foundation for Economic Education (FEE), in an article on California's new rent control law.
When you see a headline that begins with “Florida man…,” you know it’s more likely to be about some guy trying to take down a tornado with his Colt Python than it is that a resident of the Sunshine State has cracked cold fusion. In public policy circles, the words “California policymakers…” appearing in a headline are attaining a similar status.
First off, I'm impressed that not only does author know what a Colt Python is but that he expects all his readers to, as well.  Second off, equating “California policymakers” with “Florida man” is just wonderful, given the general perception of Florida man.

The article itself is OK, I guess, but it's a subject that hardly needs to be covered.  Only the most stupid of the stupid think it's a good idea.  For one thing, in contrast to the saying, “if you lined up all the economists in the world, they still wouldn't reach a conclusion,” isn't true in this case.  Even the famously always-wrong Paul Krugman acknowledges it's a bad idea.
The analysis of rent control is among the best-understood issues in all of economics, and — among economists, anyway — one of the least controversial. In 1992 a poll of the American Economic Association found 93 percent of its members agreeing that ''a ceiling on rents reduces the quality and quantity of housing.'' 
The argument that comes to my mind first, even before that fact, is the one I wrote about just back in mid-June.  Even the North Vietnamese communists saw that rent control was stupid.  In the person of Foreign Minister Nguyen Co Thach, quoted here:
Addressing a crowded news conference in the Indian capital, Mr. Thach admitted that controls … had artificially encouraged demand and discouraged supply…. House rents had … been kept low … so all the houses in Hanoi had fallen into disrepair, said Mr. Thach.

“The Americans couldn’t destroy Hanoi, but we have destroyed our city by very low rents. We realized it was stupid and that we must change policy,” he said. [Emphasis added - SiG]
It turns out that actual communists are smarter about their failures than the American "wannabe communists" in California, New York, or the rest of the Democrat party.


Old San Francisco stock photo.  You can tell it's old because there's no shit visible in the street.


Monday, September 16, 2019

The Awful Cost of Renewable Energies

I know most of my readers are painfully aware how absurd the arguments are that we hear for renewable energy from AOC (Twitty McTwitface), the squad, and the rest of the clown cars about the Green New Deal.  I happen to like seeing numbers to show me the size of the problem and I know some of you do, too.  The fundamental problem with wind and solar energy is that they're intermittent, so any amount of generation that comes from those sources needs to backed up with equivalent generation capability.  Cartoons by Josh, semi-resident cartoonist for Watts Up With That showed it this way in 2011 and it's as correct today as it was then.  In the old days, we built power stations for what we need.  Today we install the bird and bat choppers and build a backup plant capable of delivering all the power the choppers could deliver for those times when its not windy.

Applying generously diced birds to the land under the wind turbines will, indeed, 'green the land'.  In the organic fertilizer sense. Technically maybe they're not diced, just killed.

Foreign Policy offers us a summary of analysis done by the World Bank, a couple of years ago (strangely enough) in 2017.  Although they start from the standpoint of believing we need to build wind and solar farms, they bring some real data to the table.
The phrase “clean energy” normally conjures up happy, innocent images of warm sunshine and fresh wind. But while sunshine and wind is obviously clean, the infrastructure we need to capture it is not. Far from it. The transition to renewables is going to require a dramatic increase in the extraction of metals and rare-earth minerals, with real ecological and social costs.

We need a rapid transition to renewables, yes—but scientists warn that we can’t keep growing energy use at existing rates. No energy is innocent. The only truly clean energy is less energy.
The way I always heard that last sentence is "the only truly clean energy is the energy you don't use".  Same idea, different words.  The article begins by pointing out that the World Bank study modeled the increase in raw material extraction (primarily mining and refining the mine output) that would be required to build enough solar and wind utilities to produce an annual output of about 7 terawatts of electricity by 2050, or enough to power roughly half of the global economy. By doubling those numbers we can see how much more of those materials are required by 2050 to reach Twitty's goal of no carbon emissions at all. 
[T]he results are staggering: 34 million metric tons of copper, 40 million tons of lead, 50 million tons of zinc, 162 million tons of aluminum, and no less than 4.8 billion tons of iron.

In some cases, the transition to renewables will require a massive increase over existing levels of extraction. For neodymium—an essential element in wind turbines—extraction will need to rise by nearly 35 percent over current levels. Higher-end estimates reported by the World Bank suggest it could double.

The same is true of silver, which is critical to solar panels. Silver extraction will go up 38 percent and perhaps as much as 105 percent. Demand for indium, also essential to solar technology, will more than triple and could end up skyrocketing by 920 percent.

And then there are all the batteries we’re going to need for power storage. To keep energy flowing when the sun isn’t shining and the wind isn’t blowing will require enormous batteries at the grid level. This means 40 million tons of lithium—an eye-watering 2,700 percent increase over current levels of extraction.
That's just for electric power generation; essential but far from the only essential.  With no fossil fuels to run an internal combustion engine, there is no transportation left on the planet.
This year, a group of leading British scientists submitted a letter to the U.K. Committee on Climate Change outlining their concerns about the ecological impact of electric cars. They agree, of course, that we need to end the sale and use of combustion engines. But they pointed out that unless consumption habits change, replacing the world’s projected fleet of 2 billion vehicles is going to require an explosive increase in mining: Global annual extraction of neodymium and dysprosium will go up by another 70 percent, annual extraction of copper will need to more than double, and cobalt will need to increase by a factor of almost four—all for the entire period from now to 2050.
Quoting directly from their letter:
The metal resource needed to make all cars and vans electric by 2050 and all sales to be purely battery electric by 2035. To replace all UK-based vehicles today with electric vehicles (not including the LGV and HGV fleets), assuming they use the most resource-frugal next-generation NMC 811 batteries, would take 207,900 tonnes cobalt, 264,600 tonnes of lithium carbonate (LCE), at least 7,200 tonnes of neodymium and dysprosium, in addition to 2,362,500 tonnes copper. This represents, just under two times the total annual world cobalt production, nearly the entire world production of neodymium, three quarters the world’s lithium production and at least half of the world’s copper production during 2018. Even ensuring the annual supply of electric vehicles only, from 2035 as pledged, will require the UK to annually import the equivalent of the entire annual cobalt needs of European industry.
Got that?  For the small country of the UK to replace their entire fleet of fossil-fuel powered cars, they would need twice the world's annual cobalt output, the world's annual output of neodymium, 3/4 of the world's lithium, and half the world's copper production.  It goes without saying that every other industrialized country on Earth will also be trying to double or triple mine productions on all these minerals, for their use.   

Note that they're not saying we’re going to run out of key minerals — although that may indeed be possible.  It will just drastically change the impact of mining for these minerals, which many greenies feel takes too big of an environmental toll as it is.


EDIT 1327EDT 9/17: URL for killed, rare bird wasn't loading properly from live blog, but would load from Blogger's editor.  Attempting to fix.


Sunday, September 15, 2019

A Letter to My US Senators

Here in Florida we have two Stupid Party senators who are sounding downright stupid about gun rights.  Rick Scott, when he was governor, fell for the "we have to do something" line and basically enacted all of the Evil Party's gun control agenda for them.  I guess because doing something wrong is just as much "doing something" as doing something right.  Marco Rubio has already come out in favor of red flag laws and other attacks on gun rights.  Same attitude about doing something wrong. 

I need to contact both offices, so thought I'd share with you what I intend to send to both of them.  Yes, I plan to send both of them the same letter.  Yes, postal snail mail instead of email.  They count more.  This is "2nd draft" level, and may be edited some more.  One page is the optimum length for a letter to an office and this runs over.  Some more work may be in order.



Senator


In the wake of a couple of high publicity mass shootings in the last couple of months, the country is wrapped up in the fervor of “we must do something” that we in Florida went through after the Parkland school shooting. Those laws have had awful impacts already and are expected to get worse.

The sad truth, which virtually any honest observer will admit, is that these shootings simply won't be stopped by a new law on top of the thousands currently on the books.  Mass shootings are less common now than in the 1990s and society is safer in many ways. 

The two buzzwords being thrown about are “Red Flag Laws” and “Universal Background Checks.”  Both ideas are traps that will harm many, many innocent people.

Florida passed a red flag law in the legislative session in process when the Parkland shooting occurred. The protections of civil rights and “guilty until proven innocent” nature of the laws is playing out already. Just last month, we read of a St. Cloud man named John Carpenter who was the victim of having the same name as someone else who had been accused of domestic abuse. Even though the warrant he was associated by name to specified the residence was someplace he had never lived, he didn't match the physical description of the other man, and it was an obvious mistake, he was deprived of rights under the color of law. He had to hire a lawyer, take time from his life and job to go to court, at his own expense, for an automated mistake.

I'm not saying “NO” to red flag laws. I'm saying they need to have robust protection for due process. We're not talking about a privilege like a driver's license here, we're talking constitutionally recognized – not granted – human rights. If someone falsely accuses another person as a form of harassment, or to associate an allegation of instability for a divorce or other civil matter, they should subject to fines and imprisonment in line with the punishment the innocent gun owner suffers. In the case of official lack of diligence in identifying the person, as in the case with the St. Cloud man, the agency should be responsible for financial damages and court costs, as should the individual government employee who wrongly accuses someone.

The fundamental problem with the “Universal Background Checks” is that we virtually have that now. We have background checks for the vast majority of gun sales in the country now. There's no such thing as a gun show loophole and there's no such thing as buying guns from the internet without a background check. Surely you know this. The only type of sale that doesn't get a mandatory background check under Federal law is a private sale between two people, and even now it's getting harder to find such a sale without the seller thinking that getting the buyer to pay for a background check will protect the seller. Private sales are a tiny percentage of gun sales, and would be the only type of private sale between two people that the Federal law would regulate. Alcohol: can one adult sell his bottle of booze to another adult? What about selling his car to someone else? Both of those kill orders of magnitude more people than guns do.

The problem with the UBC laws, at least in the House version that was passed this spring, is that it isn't a background check law. What it does is change the definition of “transfer” from being a transfer of ownership to being a transfer of possession. If two friends are out fishing and one has rod and reel the other has been thinking of, it's no big deal for one to lend the other guy his rod and reel. If a friend wants to drive another friend's car, again, no biggie. What the law seeks to do is change that for firearms and make loaning a gun to someone the legal transfer of ownership. The stories say there will be exceptions for family but that falls far short of reasonable. Why should it matter if one person loans a gun to a friend for a few minutes, a vacation or some other reason?

Statistically, the best course of action to “do something” would be to get rid of legally-mandated Gun Free Zones laws. Dr. John Lott's research shows that well over 90% of mass shootings are in gun free zones, presumably because people aiming to get the high score in their chosen game don't like the chance of being shot first.  The question is when given that fact, do people change their beliefs and behavior.



Cordially,
blah blah blah



Saturday, September 14, 2019

Blended Ketchup

Which means catching up on a bunch of little things. 

First of all, the lightning damage story...which I started to call the neverending story, but I'm optimistic will end.  The most expensive piece of gear in my ham shack is a power (linear) amplifier made by the company that most of my radios are from, Icom.  That has not successfully turned on since the strike and mid-July was the last time it was on.  I have the service manual for this beast (it weighs 55 pounds, so shipping would be difficult and expensive), but I was hoping to bring it back to life enough so that I can turn it on and then troubleshoot it.  It might well be that the first part of that is all I need to do.

The starting point is that it smells like a power supply issue ("smells" in the metaphorical sense), and a power supply means analog electronics, which I have plenty of experience with.  If I get it started, then much of the rest is radio frequency electronics which is solidly my home turf.  It's only about twice the output power of the last HF avionics radio I worked on. 

The trouble is that there is virtually nothing published on the power supply.  There are no schematics in the service manual, just interconnection labels.  There are some schematics online, but no component values and no clues about how this blivet is put together.  The only information is hams helping each other online.  Besides that link, there's a hand drawn schematic for one part of it that another ham had trouble with, troubleshot and fixed. 

Armed with that little information, I disassembled the unit to the point I could pull the power supply module out, and started trying to find the problems with it.  Where the 240 VAC enters the unit, it goes through a little line filtering PWB that had two fuses on it.  Both of them were blown into another spacetime continuum.  Both fuses are 250V, 4A, an odd value but I was able to find the manufacturer's part number, and then find the fuses in several places.  Amazon had the best price, and I ordered many of them, anticipating having to replace them a few times as I proceed.  You can see the fuses in this picture - F2 and F1.


These are supposed to be your typical, clear, cylindrical, glass tubes with a thin, carefully calibrated wire in them.  Circuit wise (from what I can tell) those fuses are directly on 220 as it comes into the box, and after going through the fuses, the two lines go to a transformer.  A transformer for line frequencies represents a very large inductance to a lightning pulse, which can be thought of as being above 100kHz, and sometimes even above 10 MHz, based on its rise time.  I could envision scenarios in which the lightning surge dissipated in those fuses and circuits downstream would be OK. 

No joy, though.  The fuses didn't allow the unit to power on, although they didn't blow.  A little more investigation of the earliest routing of the power supply showed a couple of panel mounted circuit breakers on the the back of the amplifier.  One of those was blown open, the other seemed OK, but I ordered some of those, too, and will replace both.  I can tell that one side of the power line brought power into the box, but apparently not in a way that turned on the first stage of the power supply that generates 12V to allow it to be turned on remotely.  I think once I get that little supply to turn on, fixing things gets easier from there.

I never put my antennas back up after the dismounting that Dorian forced on me.  I moved the big HF antenna onto the back porch and stood the much smaller VHF antenna next to it.  Today, I pulled the VHF antenna into the shop to work on replacing the cable in a pleasant environment, and noticed an interesting damaged area on the cable. 


This is apparently where the cable jacket was touching the tower mast.  The area on the right of the opening appears to be melted and re-frozen copper.  The hole would be where some copper braid got blown out, or vaporized.  Because I don't see any abrasion on the (deteriorating) cable jacket, I think this is from the August 1 strike. 

I've gotten a replacement antenna rotator.  The control box was very thoroughly blown out, and the only meter check I can do of the outside unit showed it to be open, so that if I tried to rotate it with another controller, it wouldn't. 

Finally, when I'm not gathering information or buying parts for the radio shack repair, I am still working on my Webster internal combustion engine.  The flywheel has been in process since about the time of the lightning strike, when I gave up on the tool steel flywheel and bought a slice of cold rolled steel to turn into the flywheel.  I have been working on it an hour or so at a time when I get the chance.  


This will get three equally spaced 3/4" holes in that large, thin web between the inner hub and outer ring.  For that it moves from the lathe as pictured over to the rotary table on the big milling machine.  This will take about five times longer to set up than to do



Friday, September 13, 2019

Good News for Amputees From Biomedical Engineers

This week, news came out in the Institute of Electrical and Electronics Engineers (IEEE) general publication Spectrum about improvements in quality of life for leg amputees by incorporating sensation into prosthetic legs.  H/T to A Large Regular in his links for yesterday, Sept. 12.
Luke Skywalker inspired a generation of prosthetic arms, including hands that grip, feel, and respond to thoughts.

This morning, an international team of researchers led by ETH Zurich announced a bionic leg that brings similar advances to the lower body. The prosthesis sends sensor input from the foot and knee to a nerve in an amputee’s thigh, allowing users to feel the bending of the knee, as well as pressure and vibrations of the foot on the ground. And those sensations, it turns out, make a big difference to the health of the wearer.

In its first two users, the bionic prosthesis improved walking performance, boosted endurance, and reduced phantom limb pain—the feeling of having a missing limb still attached, but in a wrong or painful position.
The team began with a commercially available prosthetic from Össur, which included a microprocessor and an angle sensor in the knee joint, and added an insole with seven sensors to the foot. The modified system then transmitted the foot and knee signals in real-time, via Bluetooth, to a controller strapped to the user’s ankle.  In the controller, an algorithm encoded the sensor signals into neural signals, then delivered them to the nervous system via a small implant in the patient’s tibial nerve, located in the back of the thigh.  The patients required very little training and said the sensations felt “very natural.”
The device was tested in two above-knee amputees, who had experienced the most severe form of lower-limb amputation. In a series of trials, scientists asked them to walk indoors and outdoors on various types of terrain—for example, in a large, sandy area—with and without the sensory feedback turned on.

When the users could feel the prosthetic limb, they walked faster, felt more confident, and consumed less oxygen, suggesting moving around was less strenuous than with a traditional prosthesis.
That last paragraph is interesting.  It says using the commonly used prosthetics with no feedback  sensations is more tiring because of the lack of those feedback signals the body is trained for and expects.  Here's where it gets even more interesting to me. Even though prior studies have shown that having that neural feedback reduces phantom limb pain in arm or hand amputees, that had not been demonstrated in leg amputees until this study. 
With just a few minutes of electrical stimulation per day, one patient experienced a complete loss of pain. In the other, pain was reduced about 80 percent, said co-author Francesco Petrini, also of ETH Zurich. Yet the two volunteers had to be present in the lab connected to an external device by a cable to undergo treatment, so current use of the system for pain relief is limited.
The benefits of walking faster, feeling more confident, expending less energy to walk, and reducing pain by feeding back mechanical sensations from the prosthetic leg to the body makes it seem like a no-brainer that this research should go on.  Our bodies are clearly designed to function with those sensations, if taking them away causes pain, and that says that patients should get limbs with this technology as early in their recovery as possible.  The problem is that they don't exist yet. 

ETH Zurich's Dr. Petrini says, “We are working to develop a fully implantable system which will be able to be maintained inside the body of the patients,” like a pacemaker.  Once that system is developed, they will run a larger controlled trial with 60 patients.

Now, in my view, the ultimate answer is tissue engineering to regrow those limbs, so that lost limbs are regrown similar to how primitive vertebrates like the axolotl regrow lost limbs.  People who follow this technology speculate that regenerated/regrown hearts are probably in the range of 10 years away.  There are more types of tissue in a leg than a heart, so they're more complex, but if you're perhaps 40 or younger, you might see legs being regrown in your lifetime. 


One of the types of Össur legs as used in the study; not one of the two initial patients from the experiment.  Photo source