Kent's Long-EZ project

[Kent Ashton]

I have mentioned the hazards of circling approaches  https://www.canardzone.com/forums/topic/18661-kents-long-ez-project/?do=findComment&comment=66249   and see that the recent Challenger crash at Truckee is a typical example that killed six people: circling to land in bad visibility, got in too close to the landing runway, stalled it in.   Juan Brown has a good analysis  https://youtu.be/VT6Z--HNqlM   but he does not bring up the "look angle" illusion that gets a pilot into a square corner turning final.  It is funny problem: pilot may see that he has put himself in a square corner turning final and needs to tighten the turn (increase G) but if he increases his speed to handle the G, it makes an overshoot more likely.  I have seen pilots even slow down to try to make the turn radius smaller.  Brrrr.

 

[Kent Ashton]

I started reading this accident report, expecting it to be the recent Long-EZ crash this week that killed Marc Borum.   http://www.kathrynsreport.com/2021/07/rutan-long-ez-n966ez-fatal-accident.html   It mentions the recent accident but mainly covers a 2017 midair of the same aircraft & pilot. Reports say he was getting a flight review in the recent accident; perhaps he just got the airplane repaired.    Fate is the hunter, eh?

[Kent Ashton]

This is a good test by Russ Meyerriecks worth repeating here.  He was not happy with his cooling (new engine) and tried VGs ahead of the NACA scoop.  Before VGs he had 4.3" water differential on his manometer.  With VGs, 6".  Quite an improvement.  Someone pointed out that the increase in manifold pressure in inches of mercury corresponds to the increase in water pressure.  In my experience, this is what you can expect with VGs like this.  (pic)

To repeat a story:  I put a pitot tube in my NACA one time and hooked it up to an ASI.  The ASI would rapidly fluctuate between almost zero to freestream velocity.  A couple of VGs like this smoothed it out quite a bit.  The ASI did not reach freestream velocity but it was much improved.  My theory is that the air wants to skip over the NACA and the VGs create a swirl that helps the flow go into the scoop.  Don't try this because it eventually broke my ASI.  Use a manometer of some time an piccolo tubes above and below the cylinders.

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Both test flights had the following configuration:
* 6kft standard pressure, 55f OAT
* wide open throttle stabilized cruise
* ~2600RPM, full rich

Without VGs:
CHT1: 412f (hottest)
CHT2: 386f
CHT3: 398f
CHT4: 350f
Baffle Pressure Differential: ~4.3in/h2o
MAP: 23.6"

With VGs:
CHT 1: 377
CHT 2: 369
CHT 3: 386 (hottest)
CHT 4: 343
Baffle Pressure Differential: ~6.0in/h2o
MAP: 23.9"

Notes:
* Positive increase in cooling effect. My hottest cylinder #1 had a 35f degree drop
* The increase in cooling from the vgs appear to be effective in cruise only and not as much in takeoff and climbout. I'm still seeing consistently CHT3 spike up to 450f on takeoff and cooling off rapidly during the climb.
* I'm unsure why map increased slightly. Perhaps the vgs are directing more airflow at the intake filter and creating a "ram air" effect? Or maybe the engine is breathing easier with a higher pressurized lower section?

VG configuration:
4 ply bid right angle stock
dimensions: 1" high, 2.5" long
location: halfway between landing brake and beginning of intake naca
orientation: 2.5" apart center to center, 15deg angled inwards from airflow
glued on with clear RTV

 

[Kent Ashton]

Here is a headset I found after Lightspeed discontinued their very light passive "QFR" model.  Cheaper than anything on the Spruce website at $100 and they do the job for me.  Virtually the same as the Lightspeed QFR.   I have a couple from them.  They don't seem to advertise anywhere

https://www.wicomheadsets.com/product-category/aviation-headsets/

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Here's another tip--no charge:  If you have a disqualifying medical condition, download the FAA AME guide and peruse the checklists for approving special issuances for a particular condition.  I had a melanoma removed about 6 years ago and had the required brain MRI (melanoma can move into the brain causing a seizure).  This year I put in my paperwork for a special issuance for another condition but neglected to see that a brain MRI is required EVERY TIME you renew with a history of melanoma.  My AME didn't catch it either so it will add another month or two to the process.  Here is a pic from page 115 of the AME guide.

[Kent Ashton]

This welded-tube Varieze project has been very interesting to follow.  It is not really a Varieze anymore.  Look it up at Facebook: RaptorAirWorks.   I grabbed this latest pic of cooling for his Viking engine.  I think I would have tried something different.    I think there will be turbulence behind that canopy that will reduce the flow into the scoop.  Also interesting is his video of a failed centerspar test of a spar he bought from another builder.  It wasn't built right

https://www.facebook.com/Raptorairworks/videos/649202605129720/

 

[Kent Ashton]

Had a scare recently when the buyer of my EZ removed the old Rocky Mountain engine monitor I had used and installed a new Dynon EIS + sensors and reported the engine and oil temp were running very hot.  Suspicions were leveled at  my homemade CHT bayonets and oil cooler setup.   🙂  It seems now to have been a problem with sensor selection, sensor setup, or just test flying in hot weather.  All is forgiven from my end.  It reminds me of the saying "When you hear hoofbeats, think horses, not zebras"

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Saw this pic on Vans Airforce complaining of flare leaks on a fuel line.  Most of the comments centered on the small size of the flare (upper right), which also looks undersize to me.  'Course, not tighten the B-nut could also have been the cause.  🙂  I have not had any problem getting leak-free flares but my fuel systems are low pressure.    Use the correct 37 deg aircraft flare tool, deburr the inside of the tube with a deburring bit or tool, use a drop of oil on the flaring tool, and check that the outside diameter of the finished flare is pretty close to the I.D. of the B-nut.  Second pic is a bonus.

Edited September 21, 2021 by Kent Ashton

[Marc Zeitlin]

3 hours ago, Kent Ashton said:

Had a scare recently when the buyer of my EZ removed the old Rocky Mountain engine monitor I had used and installed a new Dynon EIS + sensors and reported the engine and oil temp were running very hot.  Suspicions were leveled at  my homemade CHT bayonets and oil cooler setup.   🙂  It seems now to have been a problem with sensor selection, sensor setup, or just test flying in hot weather.  All is forgiven from my end.

Sorry, Kent, but since you're posting publicly, I'll respond the same. That is not at all my interpretation of what's going on. Since the sensor that is now on the plane is the exact same sensor with the exact same setup as the Dynon EMS was originally installed with, and the sensor was calibrated with a candy thermometer, any statement that the issue with high OT measurements was due to sensor issue is contraindicated by the evidence. Multiple flights with the calibrated sensor verified the high OT's.

Only after the oil lines and cooler were cleaned and reinstalled, the OT's returned to a normal 180F - 190F from the previously noted 240F - 260F. Although no debris or blockage was found in either, those were the ONLY things (other than the flapper door removal in the oil cooler ducting) that changed. The problem was NOT the sensor. It may or may not have been the duct door, the cooler or the lines - maybe there was an air bubble somewhere that prevented flow - I don't know. But what I DO know is that it was NOT a sensor issue.

Now, it's possible that the issue with high OT's was completely coincidental with the installation of the new EMS. It would be a substantial coincidence, since we did not touch the cooler or the oil lines during the EMS install, but anything's possible. In that case, both the RMI and Dynon EMS's would have been reading correctly.

So no apologies needed and no forgiveness required. Zebras, indeed.

Edited September 21, 2021 by Marc Zeitlin

[Kent Ashton]

I look at it this way:  This airplane/engine combo flew several hundred hours before.  It apparently cooled well and the oil temp was normal, then the owner installed a new EFIS, wiring, and sensors and it suddenly overheated and the oil temp spiked.  I'm hearing horses.

The owner told us he checked the oil lines and found no obstruction.  The oil-cooler company said there was nothing much in the oil cooler when they cleaned it--it was new when installed.  No changes made to my air duct to the cooler although the owner removed the oil door that regulates the air flow but as I say, the duct-cooler-door had been fine before and I would bet it will be fine if re-installed.   My homemade CHT bayonets were not checked so they might have been just fine (I suspect they were).

So yeah, the new oil temp sensor was checked but that still leaves, wiring, grounding, installation error, settings error or some unknown problem interpreting the new EFIS.  

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[owner said 2 days ago]  At 2,600 rpm, in the climb, the CHTs are in the low 390’s, the oil temps stayed in the 180’s to 190’s. I flew for about an hour. When I idled for the descent the CHTs, the OT, and the EGTs, all receded appropriately.   . . . I don’t have a real smoking gun. . . .   I have two extra OT sensors to show for it, as I went back to the Dynon single-wire sensor. I have another that seems incompatible with the Dynon system, and I have the GRT two-wire sensor Marc recommended. I’ve had all three in the aircraft, at some point and can’t really return them, so I guess I’ll sell them on ebay.

Can we agree the engine has returned to nominal?  You seemed to want to blame my installation/instrumentation and guessed that the engine was actually running very hot for the past year or two but there is no evidence to support that hypothesis and it does not explain why the new installation showed hot readings initially, but now it has seemingly returned to essentially match what I experienced, without any appreciable changes to the engine or trouble found.  Horses!

[Kent Ashton]

Saw this interesting way of cutting a wing cavity with a hot wire.  Good idea.  A long hotwire tends to bow and cut across the curves in the center.  The builder has a series of Youtubes about his project   https://www.youtube.com/user/howardyin/videos

[Kent Ashton]

There is video of his spar test either on his FB site or a website.    He bought the spar and says it was defective (it broke dramatically).   However nobody except a few European builders load-test structures—because the authorities made them.  If built to plans they are very strong.    Load testing done wrong can break perfectly good parts.

there is a write up and pics of Burt load-testing a donated canard that was rejected as too dry.   As I recall, it still went to about an 11g load before cracking.    You cannot see into a spar or winglet attachment so there must be an element of trust when you buy a project.    Does the builder seem reliable?   How did he checkoff steps in the plans?   Do the layups look good IAW Rutan’s guidelines?    Most builders are very careful;  I have seen a bad project but it was a builder who never saw another project under construction in the days before the internet.    These days there are many good builder sites you can study and compare to what’s for sale

[Kent Ashton]

17 hours ago, Kent Ashton said:

There is a write up and pics of Burt load-testing a donated canard that was rejected as too dry.

The writeup and some pics of this are in CP 45     http://www.cozybuilders.org/Canard_Pusher/1985-07_cp-45.pdf

   This "extremely dry layup" went to 10G before it failed.  I think the pic below is from that test

[Kent Ashton]

My Cozy has not flown in a year while I fiddled with getting a Special Issuance medical.  The medical approval finally came through--five months after submitting the paperwork.  It expires in 5 months but I think I will get back on Basic Med which will be good for two years.  Anyway  .. . .

The airplane had a worrying miss on one of the LIghtspeed Plasmas.  Low takeoff RPM and  an alarming miss running on that one Plasma.  I thought maybe it was fouled plugs.  Nope, they are almost new.  Plug wires are pretty new.  I thought maybe the screw-on sparkplug caps were loose.  Nope.  One time I had a Lightspeed box that suffered a broken connection to an internal chip.    It seemed to be a manufacturing defect but Lightspeed did not publicize it.  Bad on them.  I doubt thst is the probem here.

Ordinarily, the boxes are pretty stout.  One  time I had corrosion in a coil tower connection to the plug wires that caused an engine miss.  I see that Klaus says a disconnected sparkplug is very bad for the coils and a corroded connection could mimic that.   I suspect my problem is going to turn out to be a bad coil.   News at 11.   The nice thing about the Lightspeed is that they are pretty easy to troubleshoot.

[Kent Ashton]

Good 360 photo of a Concorde cockpit here   https://www.facebook.com/aerospacebristol/photos/3534327836603934

Ordinarily I eschew FB but the Contact Magazine page    https://www.facebook.com/www.CONTACTMagazine/    is worth reviewing periodically  before all the interesting stuff disappears at the bottom.  Like this Archon SF-1 (pic).  An ultralight F-35 look-alike that would get pilots to walk out of the FBO.  🙂

Also jump to this video of a Facet fuel pump teardown at about 4 mins.

https://youtu.be/Dtf66p8M11g

 

Edited October 30, 2021 by Kent Ashton

[Kent Ashton]

Saw this neat idea (pic) on the VansAirForce site for making an articulated borescope camera .  For about $25, you can buy those borescopes on ebay that will wifi-link to an iphone.  I think I paid several hundred for the Vividia 400 model.  However, Mike Busch says he can sometime inspect the cam by removing the oil dip-stick tube and feeding the Vivida through the hole.  The one below might do that with a stiff wire holding the shape. 

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In other more expensive news, one of my LIghtspeed Plasma ignitions gave up.  This was an original Plasma, 25 years old.  I think I got it on ebay.  The engine missed and ran rough under load on one ignition (dual systems).  After futzing around with coils, wires, plugs and swapping outputs of the two boxes, I established that the miss followed one of the Plasmas.  A trigger circuit went bad and Lightspeed said it could not be repaired.  The newer Plasmas have some updated features but AFAIAC, there is very little to be gained with the newer systems.  They may be a bit easier to mount the crankshaft triggers; you can read the advance and manifold pressure.  They may be more reliable but up to now, I have not had any problems except to replace a coil.

Lightspeed said the 4-cyl version does not need ventilation to the box if inside the cockpit (6-cyl does) but I think I will ventilate them.

BTW, I noticed that the caps on my Autolite 386 plug were somewhat loose.  I hammered the male threads a bit to make them tight but maybe there is a better way.

[Kent Ashton]

Saw this idea for mounting an oil cooler on a Cozy but to be frank, I don't like it.  It may work somewhat but consider:  the airflow has to enter the NACA, look around to find the oil cooler and make a twisty turn around the air-control door, enter a duct to the cooler and make another 90 deg turn to go through the cooler fins.  Nothing is making it enter the oil cooler duct except plenum pressure and the area above the engine is not a particularly low pressure area--there is certainly no suction pressure there.  If you were an air molecule, would you rather take that twisty-turnie route or would you just take a path though the fins or leak out around the engine?  If I was a lazy air molecule, no way I would want to make all those tortuous twists and turns.  I would just hang out in the lower plenum with my other molecule-buddies until I could find an easier way out.

OTOH, If I could just enter the NACA and shoot straight up and through the oil cooler mounted at the top of the cowl and escape, I would do that versus tunneling through the fins.  This is why oil cooling is pretty decent with the plans top-mounted cooler and a block-off is necessary in the winter.  Yeah, I (a lazy molecule) cause a little more drag as I shoot out into the airstream but I am FREE! (and taking your oil heat with me!)   🙂

Edited October 31, 2021 by Kent Ashton

[mquinn6]

Agree - but also realize a slow moving air molecule will absorb more heat than one that is going mach 5...  (as long as it is able to get outta there when it is warmed up!).  I soon will be playing the black magic efforts of routing for optimum cooling.  Formula I will be using in my "potion" (as it is Halloween today):  Focus the air where it needs it most =cylinders and oil cooler, get the air slowed down as soon as it enters the engine bay...  use a basic formula of 1 to 3 (inlet to outlet size) - or evaluate viability of exhaust scavenge suction technique...   We will see how the brew works out!

 

[Perry]

On 10/31/2021 at 11:18 AM, mquinn6 said:

Agree - but also realize a slow moving air molecule will absorb more heat than one that is going mach 5... 

 

Throwing this out for everyone's edification.  The Reader's Digest Condensed Version is: Heat transfer rate is proportional to temperature difference. Thus, more heat will be removed if the air is moving faster (aerodynamic heating from supersonic flow notwithstanding.....).

https://www.engineeringtoolbox.com/arithmetic-logarithmic-mean-temperature-d_436.html

You don't have to study the equations, just read the first sentence.  Also explains why counter-flow works best in radiators.

Bonus tip that applies this time of year in the northern hemisphere: If you want to get more heat out of a wood stove, place a fan to blow air over the stove.  It's a great real-life application of the theory.  The fan pushes away the heated air that is next to the hot stove surface faster than ordinary convection would remove it.  The cold(er) air that replaces it is able to have its temperature increased more than air that is hotter.  Thus, more sensible heat is transferred to the room while burning the same amount of wood.   Cheers!

[andymeyer]

So, yes - this is true...

But, it's diminishing returns... doubling the flow rate does not double the heat transfer. It increases, but doesn't double. In addition, to double the flow rate requires a lot more pressure - ~4x so it's difficult to double the flow rate inside the cowl without modifying the fins. Modifying the fins (reducing restriction - bigger gaps or less fins) would drastically reduce the heat transfer.

Slower flow rates result in the fluid being closer to the stove temperature, but cannot remove near as much heat. 

[Kent Ashton]

Saw this chart in a discussion of engine dehydrators posted by a chap in Wisconsin (H/T Don Pansier).  I have used a dehydrator but now I just blow the moisture out of the crankcase.  He purged the crankcase for 8 mins and measured the humidity for 72 hours.  It brought the humidity down from 60% to about 38%.  In the right side of the chart he purged for 8 mins then used a dehydrator which brought the humidity into the 20% range.  Dehydrators are not hard to make (pic 2).   I've read before that steel will generally not rust below 40% RH.  I would like to use my dehydrator but I don't have power in the hangar.

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By request I collected the data on a purge only, shown on the left side of the chart, the purge was about 8 minutes while I wiped down the plane after flight.  The right side of the chart depicts data after a 8 minute purge and 4 hours of dry air.  The data indicates a significant reduction in the dew point using the purge followed by dry air.

 

Edited November 18, 2021 by Kent Ashton

[Kent Ashton]

Some notes on LIghtspeed Ignitions:  One of my original Plasma I ignitions developed a high-speed miss.  I sent it off for a check and Lightspeed said it was 25 years old and too expensive to repair.  The electronics looks rather intimidating (pics 1,2) but my EE buddy said it is likely a bad transistor or capacitor that could be tracked down and replaced but I had already sprung for two used Plasma IIIs.  (I use two ignitions--one triggered by a crankshaft sensor, one triggered by a hall effect sensor mounted in a magneto hole.)

The Plasma IIIs use a newer crank sensor ("Mini-Sensor") (pic 4) than the old Plasma I but either box can use the same Hall Effect sensor I have now, however the D-Sub connectors are different from the older models so there is a bit of rewiring to use my existing Hall-trigger device.  The Mini Sensor unit came with a prewired cable.  The Mini Sensor is easy to mount if you already have the case drilled for Lightspeed's older trigger

With the newer Plasmas, a ring with small magnets is installed inside the flywheel (pic 5).  The magnets trigger the mini-sensor and the Plasma linked to it.  Installing the ring requires a bit of precision but I have a mill and a rotating table so it was pretty straight-forward.  The mini sensor must be adjusted to a .030"-.060" gap from the ring.  I have learned to measure the depth of the ring from the inside flywheel surface and make a small jig that allows me to set the gap at a nominal .045" before installing the flywheel+magnet ring. (pic 3,4)   It is probably not necessay as you could get a feeler guage in the gap later.  Note that a crankshaft has some fore-and-aft movement so check the gap later when the crankshaft is pushed forward as in flight

I noticed that when mounting the flywheel with the alternator belt installed, it would be easy to damage the trigger ring.  So I painted a note on the flywheel.  I have various note written in paint-stick on my flywheel:  "Caution: damage to trigger ring", "TDC #1",  "Torque [prop extension] to ___", and "Alterntor Belt!!" because I have forgotten to install the belt before the prop extension.  😞

 

[Kent Ashton]

Two things:  One is this informative post by Paul Saccani discussing electronic "whiskers" from lead-free solder.  I have heard of them but I didn't think to look for them in my broken ignition box.

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This brings to mind some thoughts about improving the reliability of Commercial off The Shelf (CoTS) electrical and electronic modules incorporated into aircraft.

 

CoTS are generally produced to Reduction of Hazardous Substances (RoHS) standards which eliminate lead from solder and tin plating.  In aviation, tin and zinc whiskers are a serious issue for electronics and electrical systems, most aviation standards require lead in electrical and electronic tin and zinc coatings, and in solders to prevent whisker growth.

 

It isn’t practical to do anything about pure tin plated leads on components (but if you are making something from scratch, you can dip the leads in solder), but the main issue is with lead free solder, and you can easily do something about that.  If before using the commercial modules, you rework all the joints by reflowing the solder and adding a small amount (ca. 6%) of 50/50 fluxed electronic solder and removing any excess.  It only takes a small addition of lead to the alloy to prevent tin whiskers growing.

 

Tin whiskers are nearly invisible and grow to in excess of 10mm, and go straight through protective lacquer coatings.  How and why they grow isn’t fully understood, but we do know that lead stops it from happening, and high reliability electronics usually use lead to prevent it.

 

Tin whiskers are now one of the leading causes of failures in CoTS electronics, due to the shortsighted EEC RoHS directive.

 

Some of the new alternative whisker mitigation methods also fail, in novel ways;

 

These are micro-tube tin whiskers growing despite nickel being used to prevent tin whiskers.

 

It might improve reliability to pot un-potted CoTS modules in epoxy resin, it will very likely prevent whisker growth, prevent moisture getting in and reduce vibration induced failures, though heat management needs to be considered.  If you don’t want to be able to repair it and don’t want to reflow the solder, this could be the easy way out.

 

If you have the choice, a potted CoTS module, such as the buck converter Marc chose on this occasion, is going to be a much better bet than an unmodified, unpotted CoTS module.

and

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G’day Bill,

twenty years old is less cause for concern, the RoHS directive didn’t come into force until 2004.  After that date, most CoTS electronics is lead free.  Before that date, most would have lead content of at least 3% in tin coatings and solders.  But pure zinc plated enclosures and the like would still be likely to make zinc whiskers - when this “fur” breaks off, it creates a headache.  Simple spray on circuit board lacquers are effective against that risk.  With LSE, clearly Klaus should know best whether or not lead free solder has ever been used in production, but it is likely that pure tin plated components would have been used sometime after 2004, unless strict QA designed to prevent it has been used, even if components with lead in coatings were specified.  Pure tin coatings turn up a lot, even when 3% lead is part of the specification.

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Another think is the Archive.org--(Google Wayback Machine) a great resource for finding dead websites.  I was looking for a dead link to this lightweight headset (pic) and found it there.  H/T Drew Chaplin

https://web.archive.org/web/20160114213330/http://www.cozy1200.com/geeklog/article.php?story=20070427102533266

Edited November 30, 2021 by Kent Ashton

[Kent Ashton]

Off topic but I feel compelled:  I am 74 and have had two heart blockages that would have killed me but for stents.  For years I have taken statins but I am going off them.  More and more evidence is coming out that statins are over-hyped and hurt you.  For example, a major study showed statins lowered the mortality rate from about 3% without statins to 2% with (i.e., 1%).  The drug companies trumpet that as a "30% reduction in mortality".   Statins are a $1Trillon industry.  Side effects are barely discussed by doctors: muscle weakness (yep), low sex performance (yep), cognitive decline (yep), high blood sugar & diabetes (yep).  Yes, they reduce LDL and increase HDL but there is little evidence that they improve mortality, in fact, evidence shows otherwise.   I feel more educated now on what cholesterol does and I am becoming convinced that insulin-control is more important through keto dieting and intermittent fasting.   Here are some things you should check out.  PM me if you want.

This Doc brings up issues with statins I am reading in many places  https://youtu.be/Odvt4EaGPLw

This Dr. Nadir Ali gives a very entertaining & informative discussion of cholesterol  https://youtu.be/o_QdNX9etCg  https://youtu.be/qXtdp4BNyOg

This fellow has a good channel devoted to Keto dieting   https://www.youtube.com/channel/UC3w193M5tYPJqF0Hi-7U-2g

You might ask why I've had two heart attacks.  I have always eaten better than many people but we ate the usual carbs: potatoes, fries, cookies and my glucose scores have climbed over the years.  I have been overweight since I retired.  The statins have not helped and I believe I'm slowing getting prediabetic.  Check with me in 5 years.  🙂

 

I feel that I have friends here and I hope you will consider this.   -Kent

 

[mquinn6]

100% agree - would like to add one VERY significant factor (knowing you personally) - STRESS plays a HUGE roll in our heath.  Our feelings influence our eating habits, our sleeping habits, and our life as a whole....   I have not seen a Dr. in over 10 years (other than my 3rd class) and my optometrist (as I cannot get contacts without a recent exam (eyes have not changed in 20 years - same prescription).

I have dedicated 2 hours every day (probably longer than I NEED to, but it feels sooooo good) to meditate (not contemplate - actually just take a good look at myself and what is going on in noggin as if I was looking at myself in a mirror.)

   I am amazed at how I react thru the day so differently than before.  I am recognizing right now that the job I am doing is impacting my health (too many hours, not enough good feeling that I am getting stuff done, and not getting ANY build time!!!)

 

[Kent Ashton]

Small change to my Lightspeed ign power diagram - add grounds to ign power shields

 

[mquinn6]

I believe there is something about not grounding both sides of a shielded cable...  (something I recalled from Bob Knuckles talk or book...)