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About chanik

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    Semi-private Pilot

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    San Jose
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  1. chanik

    Battery Charger

    Or running a load like the lights for 1 minute to bleed off the surface charge. Then turn everything off and measure
  2. chanik

    Stabilator Nick: Cosmetic?

    If you ever need it, I do know of a spare CTSW stabilizer NIC (new in crate) that you could have cheap. I looked at it though and am pretty sure it needs the balance mod done so would have to go to Lone Mountain first.
  3. chanik

    Diesel From Air & Water

    The only reason capturing flue gasses does not make sense is that if you have fuel to start with, coal or much better natural gas, then there are much more efficient, direct chemical process pathways to making diesel. Rather than burning -> electricity (~40% eff) then capturing exhaust (~90%) then running electrolysis on CO2 and H2O (70% according to Audi). That's 25% overall versus over 60% for modern FT process
  4. chanik

    Diesel From Air & Water

    I find it interesting to ask the question the other way around: How could it be viable. First, crude would have to at least double in in price, but that day will surely come. Audi's greenwashed version about grabbing atmospheric CO2 is warm, fuzzy bullshit. But there are streams of concentrated CO2 to be had, mostly from refineries and gas/oil drilling. Lot's of CO2 comes out with natural gas; often also with oil fields. Also, wind power suffers from user-demand mismatch (much of the capacity generated at night is unused since electricity demand is massively lower). So I could see a big windfarm in Bahrain or North Dakota augmenting fuel output. Not so sexy a story but a much more practical one. All of this will be irrelevant, of course, once the water fueled engine comes to market if the automaker's/oil companies ever stop conspiring to keep the secret of chemically reasonant magnecule based oxyhydrogen production from getting out.
  5. chanik

    Diesel From Air & Water

    One gallon of diesel embodies ~37kWhr of energy, which means you can get 37kWhr of energy out by burning it, so long as all you want is heat. IC engines are only ~32% efficient at turning heat into motive force so 13kWhr of useful energy best case for spinning things like propellers. (See what that is in Li-ion batteries, just 10Whr for an 18650 cell and you'll understand why electric planes don't make much sense.) Anyway, if Audi's process is 70% efficient then they need inputs of 53kWhr to make a gallon of e-diesel. Electricity is a pretty useful fuel source to begin with and has generated costs of $0.04 and up (and that's only coal based)http://upload.wikimedia.org/wikipedia/commons/c/cc/LCOE_comparison_fraunhofer_november2013.svg, versus oil refining which generates diesel at ~$1.50 per gallon. If you start with coal, there are more efficient ways to turn coal into fuel without transitioning through electricity by making CO and H2 directly from Carbon via liquefaction for the Fischer Tropsch process. So wind generated electricity can optimistically be $0.06 and up meaning Audi could make diesel at just more than twice the cost of refining except they need a concentrated source of CO2 which is NOT the atmosphere (notwithstanding the pronounced greenhouse effect CO2 is just 0.35% of air) They would have to efficiently distill about 500m^3 of air just to get the 220mol of CO2 needed to make one gallon.
  6. chanik


    I threw out a bunch of old lock washers. Must have gotten brittle since they all had cracks. On a slightly more serious note, oil can only go bad if exposed to oxygen. It sits deep in the hot earth for 100s of millions of years after all. I think the OEMs are (justifiably) paranoid that an oil quart with a potentially broken seal will, subjected to thermal swings, breathe in and out and slowly oxidize over a several year period. Sealed I would readily use 10yr old oil after a good shake.
  7. chanik

    Gemini Diesel Chases Rotax

    They seem to substantially over-claim http://www.wingsforum.com/viewtopic.php?f=313&t=22131
  8. chanik

    Flight Pro - ceases to exist?

    Because of this I switched to iFly on my Android. I was pretty happy with avilution but I have to say iFly is a better and more comprehensive product
  9. chanik

    Alternator whine

    A good test is whether the whine shifts frequency with engine RPM. Losing the cap will do it for sure. Incidentally, that Kemet cap is fine for SLSA as well. It meets ROtax specs and they do not call out anything specific.
  10. chanik

    Failed ignition modules

    The Xbox crisis was due to a particular bad type of solder used with a ball grid array, on a very hot graphics chip. The expansion and contraction crated microfractures over time. But fine pitch parts are quite a bit different than bulk devices with big solder pads. Xbox is legendary because it was such a glaring exception. Rigid encapsulant makes vibration almost impossible in these units anyway. My point is that all electrolytics have finite lifetimes but even a 1000hr cheap device can make it to 4000hrs if you keep it below 85C
  11. chanik

    Failed ignition modules

    Nope. Pb free often creates intermittent contacts as the solder is harder to wet and easier to crack; however it tends to manifest as infant mortality and not after some hundred of operating hours. And while you can often find a bad connection via thermal contraction using freeze-spray on a board, you would never expect that to be repeatable across many boards and with such a small shift in temperature
  12. chanik

    Failed ignition modules

    So it isn't the only failure mode, Another possibility is that they washed their boards with a halogenated solvent like Trichlorethane. Which gradually destroys the aluminum. It's all conjecture, but that mode is the one that would explain cooling as a common fix. Eroding aluminum leads to high leakage current through the cap which is greatly reduced with lower temperature. resistors, chips and transistors, etc will not care about 40C -> 10C temp shift.
  13. chanik

    Failed ignition modules

    But the Temp thing is a huge factor. It follows the arrhenius equation which boils down to: every 10C less temperature doubles life. So in a cool climate and if you happen to have good airflow over the top of your engine (airflow and engine temps seem to vary quite a bit from CT to CT) then you could get to 4000hrs. I got to 850hrs and the other pair that failed here at RHV failed at ~1000hrs. There is also a Remos here at the field with starting issues with close to 1800hrs about to get new modules. (Victory Aero does all the LSA work at RHV)
  14. chanik

    Failed ignition modules

    1%? Ultimately about 100% of these modules will fail. Their start circuit is based around an RC delay using an electrolytic capacitor and all such caps, like batteries, have limited lifespans which are greatly shortened by heat http://www.mouser.com/pdfdocs/ELNAReliabilityAlumElecCaps.pdfmainly due to gradual loss of electrolyte. Good commercial caps are over 10,000hrs, like the Kemet one I suggest for battery backup but cheapo ones are often rated as low as 1000hrs at 105C which coincidentally is about when these modules can be counted on to fail.
  15. chanik

    Pipistrel deployed ballistic parachute succesfully

    Not sure what the policy is about removing crashed planes. Sure not cheap to do. Funston lake is the site to fly to