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onetrack

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Posts posted by onetrack

  1. I've driven around Warburton and it is unbelievable that a town such as this could exist in modern-day Australia. The whites are locked inside their 3M high wire compounds every night, along with guard dogs.

     

    Every second vehicle in town is unregistered and has at least 2 broken windows and 2 bald tyres. The cops turn a blind eye.  In fact, the "tour of duty" for cops there, is limited to several months, as I understand (BIL is ex-copper).

     

    When I drove around town, I could have been forgiven for thinking I was in the very worst of a South African shanty town slum with rampant gangs.

     

    In one street I drove up, barricades of tyres and rubbish blocked the entire street - because the mob up that end of the street, were fighting with the mob up the other end of town.

     

    That was their way of stopping the other mob from driving past and hurling rocks and bricks.  I really would have liked to have taken photos, but you are banned from taking photos of the locals, and the instant you produce a camera, you are likely to be attacked.

     

    On the outskirts of town, there were clothes strung through the bushes, beds laying under trees - and rubbish everywhere. These people are not Stone Age, they make Stone Agers look positively educated, peaceful, and civil. The drug problem there is enormous.

     

     

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  2. It seems that someone has told the City of Greater Geraldton, that the way forward to great income is establishing a pilot training centre.

     

    Towards that end, they are bending over backwards to assist any prospective pilot school starters, and paid Crothers to issue a prospectus. Good luck, Geraldton, it could take a while for someone to put their hand up.

     

    https://thewest.com.au/news/geraldton-guardian/sky-is-the-limit-for-geraldtons-pilot-school-bid-ng-b881162124z

     

    https://www.cgg.wa.gov.au/profiles/cgg/assets/clientdata/pilot_training_academy_opportunity_geraldton_australia.pdf

     

    They have been upgrading and extending the Geraldton airport runway, so I guess that's at least one proactive move.

     

    https://www.cgg.wa.gov.au/your-council/key-infrastructure-projects/geradlton-airport-upgrade-project-2018-19.aspx

     

    My experience of Geraldton is that you'd need to put armed sentries on every aircraft, because they'd be stripped or stolen, within 5 mins of being left unattended.

     

     

  3. Reminds me of the oft-repeated quote from an interview of Ernest K Gann - "The only time you can have too much fuel in an aircraft, is when you're on fire!"

     

    He was darned lucky he found a patch of scrubby ground to land on - there's some pretty heavy timber in a lot of that area around Burra Rock. W.A Goldfields trees are quite unforgiving, if you have no choice but to land in them.

     

    Burra-Rock-landing.thumb.jpg.8b2c593ebfaf8f898d2defe3928d4fba.jpg

     

     

  4. Old K - Your suggestion of a lightweight SLA battery upstream of the LiFePo4 battery is definitely one way to offer some protection for the charging system and avoid voltage spikes.

     

    However, to me, it appears the best idea is to go back to the original SLA battery, and dispense with the LiFePo4 battery, until you can figure out an onboard dedicated charging arrangement for the LiFePo4 battery.

     

     

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  5. Old K - I'm not sure where to start - but I'll start on the Jab alternator.

     

    1. Every engine-driven alternator produces an AC current, which is rectified into DC by about half a dozen diodes, and the charging current is then controlled by a voltage regulator.

     

    Every automotive/aviation alternator ever made has a VR - it is sometimes mounted on the outside of the rear of the alternator, other times it is mounted internally.

     

    Current-design alternators often have the brushes and VR combined into one unit. You remove the VR and the brush assembly comes out with it.

     

    2. The Jab alternator does use permanent magnets, so it does not need the exciter wire from the battery for electromagnets, which is the normal design for nearly all other automotive alternators.

     

    3. You must never totally disconnect an alternator whilst the engine is running. To do so will create a massive voltage spike which will fry the alternator, and possibly, many other electrical components in the system.

     

    The Jab community website discussion (below) gives some information on the Jab alternator setup. Their alternator regulating and controlling system is different to the standard automotive arrangements.

     

    The use of a crowbar module (usually a box of combined electrical trickery) is not common, but I can see what they're trying to achieve. The Wiki mob describe crowbar circuitry devices quite well.

     

    https://jabiru.net.au/community/engines/voltage-regulator-functionality-and-connections/

     

    https://en.wikipedia.org/wiki/Crowbar_(circuit)

     

    Onto the LiFePo4 battery.

     

    1. It's a lie that all LiFePo4 batteries can be a total drop-in replacement for L-A batteries. This has caused a lot of grief to a lot of people, particularly because of the highly specific charging requirements of LiFePo4 batteries.

     

    2. A standard automotive/aviation alternator and regulator arrangement is inadequate for charging LiFePo4 batteries. 

     

    3. A 12V L-A battery has 6 cells at approximately 2V per cell. In practice, the L-A cells run around 2.1 to 2.2V. They need a fast initial charge, then a float charge - and they can cope with being overcharged fairly constantly.

     

    At the worst, an L-A battery receiving a constant overcharge will boil the acid solution in the cells. At the very worst, the cells will boil dry, and you will end up with a buggered L-A battery. It takes a lot to do that, they're a pretty durable and forgiving device.

     

    L-A batteries like being charged at around 13.8 to 14.2V. Alternators usually max out at around 14.5V. You can charge at a higher voltage, but anything over about 14.7V creates gassing and heat in an L-A battery.

     

    Alternator regulators are set up to charge L-A batteries - to provide an initial fast charge, then reduce the charging rate to a float charge.

     

    The L-A battery provides the "cushion" in an electrical system - taking current from the alternator, even when charged, to ensure the alternator doesn't blow, with a complete current draw shutoff, and a severe voltage spike.

     

    4. A 12V LiFePo4 battery has 4 cells at 3.2V each. It needs a charging rate of around 14V to 16V, and it is more tolerant of higher charging voltage than an L-A battery.

     

    5. An LiFePo4 cell will be damaged if the voltage over the cell falls to less than 2.5V, and damaged if the voltage over the cell exceeds 4.2V.

     

    Here's the important bit -

     

    6. The cells of an LiFePo4 battery do not auto-balance at the end of the charge cycle. The cells in an LiFePo4 battery are not 100% identical. Therefore, when cycled, some cells will be fully charged or discharged earlier than others.

     

    The differences in charge between cells will increase if the cells are not balanced or equalized from time to time.

     

    In an L-A battery a small current will continue to flow even after one or more cells are fully charged (the main effect of this overcharging current is decomposition of water into hydrogen and oxygen).

     

    This current helps to fully charge other cells that are lagging behind, thus equalizing the charge state of all L-A cells.

     

    The current which flows through a fully-charged LiFePo4 cell however, is virtually zero, and lagging cells will therefore not be fully charged.

     

    Over time, the differences between cells may become so extreme that, even though the overall battery voltage is within limits, some cells will be destroyed due to over-voltage, or under-voltage.

     

    An LiFePo4 battery therefore must be protected by a BMS that actively balances the individual cells and prevents under-voltage and over-voltage.

     

    The type of BMS fitted to LiFePo4 batteries can vary widely, according to manufacturer and according to how the manufacturer thinks the battery will be used. The BMS of these batteries can also vary widely, according to how cheap the manufacturer is.

     

    Most of these BMS use dual MOSFET's to switch the charging current according to the cell demand/requirements.

     

    The MOSFET's are coupled with an Integrated Chip with additional electronic control devices built into the chip to prevent voltage spikes, indulge in cell balancing, and control other electrical parameters. We're getting into high-end electronics here.

     

    Suffice to say that the simple basic engine alternator and regulator is not up to the job of charging LiFePo4 batteries - a dedicated LiFePo4 charger really is required to match the electronics and requirements of the LiFePo4 battery.

     

    As regards your intermittent and transient power loss - I'm struggling to envisage exactly what is causing it, but I suspect it's related to the peculiar Jab alternator charging arrangement, and the crowbar module - and the LiFePo4 battery possibly causing a sudden and major drop in amperage draw, as it rapidly reaches full charge - thus causing a voltage spike, and activating the crowbar module, and making it shut off the electrical power.

     

    I'm not sure if the Jab crowbar module stays shut off, or reconnects the power once the voltage spike ceases. One would imagine the Jab electrical designers provided the security of the latter.

     

    Without an inspection of the aircrafts complete wiring and charging circuitry devices, and what they comprise exactly, and how they operate - by someone highly skilled in electronics, I think you will be shooting in the dark.

     

     

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  6. My battery supplier claims it has all necessary charging management built in, being a "drop-in replacement" for normal lead batteries. Trouble is, he's not going to divulge any details of how it works.

     

    It appears I need a regulator that will guarantee the charge voltage won't exceed 14.5v- and/or a spike arrester.

     

     

    Old K - The basic problem you have, is a LiFePo4 battery has a need for its charging system to shut off, period, when the battery is fully charged. Essentially, a disconnect of the charging system.

     

    You can't do that with an alternator, its internal voltage will soar and it will fry itself. So, you need a dedicated onboard LiFePo4 charger to handle the charging current supplied by the alternator.

     

    Redarc make such a unit - but it's not cheap. It's aimed at the RV, 4WD and boating market, where solar panels are often used in conjunction with an engine alternator, to provide dual supply paths for the battery charging.

     

    I'm not sure that this charger is the exact answer to what you're looking for, for your aircraft - but it does possess the correct charging algorithms, the correct charging voltage, and the correct charging method (including a total shutoff) for the LiFePo4 batteries.

     

    The problem is that all other chargers and regulators work on supplying a "float" charge to enable the alternator to keep functioning properly and to enable batteries to receive their system of final charge.

     

    But the LiFePo4 has no requirement for a float charge, and a float charge is actually detrimental to an LiFePo4 battery.

     

    So a way must be found to set up a separate charging system for the LiFePo4 battery, whilst ensuring that current being produced by the alternator is not shut off completely, and that there's some way to utilise the charging current produced by the alternator, even if it's only a trickle of power useage.

     

    It's annoying that the battery supplier will provide no information on what the inbuilt BMS is on their battery, or how it even operates.

     

    But the system they provide is bound to only be a current-limiting arrangement, and not have any extensive ability to produce charging algorithms, or control the system of charging.

     

    https://www.redarc.com.au/dual-input-25a-in-vehicle-dc-battery-charger

     

     

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  7. Retailers price their product according to what the competition is, and the demand. High demand means the product flies off the shelves faster than they can order it in, so the retailer ramps up the price.

     

    That's the beauty of the internet and search engines today, I can go looking for a product, and usually find a 30% to 50% reduction in pricing from the initial price quoted, within a few minutes.

     

     

  8. Spacey, the general rule is, if you want a much lighter battery, be prepared to have your wallet lightened considerably.

     

    Lead-Acid is cheap power, with a weight penalty, Li-Po and Li-FePo4 is lightweight power with a major cost penalty.

     

    You can be looking at several hundred dollars for a Lithium battery, as compared to maybe $130-150 for a simple old Lead-Acid battery of comparable power output.

     

     

  9. Old K - Li-Po batteries have a greed for charging input like no other battery. They will gobble up 100 amps or more of charging input with pleasure, and be looking for more.

     

    For this reason, nearly all the bigger Li-Po batteries today come with inbuilt charge controllers, to limit the charging input to avoid damage to alternators and regulators.

     

    If you have fitted a Li-Po that doesn't have a charge controller inbuilt into the battery, that could account for a lot of your problem.

     

    If a Li-Po is sucking a huge amount of amperage from your charging system, it will be reducing the charging voltage, thus possibly creating problems.

     

    You need the correct charging algorithm and a charger specifically set up for Li-Po batteries. Li-Po's must never be overcharged and charge input must be stopped completely when the Li-Po is fully charged.

     

    In fact, Li-Po's perform better, if not fully charged. They will cycle more efficiently and for longer, if their SoC is kept between about 20% SoC and 90% SoC.

     

    The Li-Po charge and drawdown parameters are vastly different to Lead Acid batteries, because their chemistry is vastly different.

     

    Battery University is a good site to study up on battery technology. The bloke who runs it is a former battery engineer, and he knows all the various battery technologies inside-out.

     

    https://batteryuniversity.com/

     

    http://www.enerdrive.com.au/can-charge-lithium-battery-lead-acid-charger/

     

     

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  10. Once again, the Brazilians have spent a heap of time, money and effort producing something that provides no real engine benefits, no technological advances, no weight reduction, and no fuel economy gains. 

     

    I really do wonder what the aims of these engine development programmes are, and if anyone actually wrote down attainable and important targets for their redesign.

     

    At $12K for a MotorAV engine, you might as well go and buy a Revmaster 2300 for under $9K and have a VW engine that was designed and refined over 40 years or so, by a bloke who is an engine design expert.

     

    The bragging rights about snaring Bill Brodgen from Continental Motors doesn't hold any water for me, Continental were still manufacturing 4 and 6 cyl side valve industrial engines with abysmal power output in the mid-1970's.

     

    These engines designs dated from the early 1930's. I'd like to think that engine technology has advanced at a pretty exciting rate over the last 40 years, at least - but companies like Continental are classic industrial dianosaurs - "We've always done it this way! - it works, why do you need to change anything?"

     

    If the Japs were into aircraft engines like they're into automotive engines - by today, we'd have a Japanese IC aircraft engine available, that weighed 50 kgs, produced 200 reliable HP, ran as smooth as silk, and had a 3000 hr TBO.

     

    Honda are producing their new i-DTEC 1.6L diesel with aluminium heads and block, high-swirl combustion chambers, chrome-moly steel pistons, a variable geometry ECU-controlled turbocharger with intercooling - and it produces 118HP at 4000RPM and weighs 47kgs less than their previous 2.2L diesel engine.

     

    This new engine features weight-saving in every single engine component, high plateau bore honing to reduce friction, plus a special synthetic oil designed specifically for the engine. All this translates into 3.7L per 100kms on the highway in a Honda Civic.

     

    If Continental had advanced with their technology and design like the Japs have done, they just might be producing hundreds of thousands of lightweight aircraft engines today, instead of being an industrial and technological laggard.

     

     

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  11. The 737 MAX is a classic example of a company trying to squeeze too much out of an existing designs limitations.

     

    If Boeing had bitten the bullet and started with a clean sheet new aircraft design, to match the new bigger engines, rather than trying to shoehorn the new engines into an airframe that was designed in the early 1960's, the total cost would have been much less.

     

     

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  12. Literally hundreds of millions of cars run on our roads utilising fuel injection - and have done for more than 40 years, in some cases.

     

    Todays EFI is efficient, highly reliable, and a fuel-saver - and it's much more likely you would have a rotating/moving major engine component failure (valve, rings or piston), than an EFI component failure, if you had EFI fitted.

     

    Carburettors may be very simple, but they are as anachronistic as wire strut wing supports, and bicycle wheels for undercarriage.  074_stirrer.gif.f7f0365dccba2c0c4d074e832eec2536.gif

     

     

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  13. Old K - What were you doing, operating a Michigan loader at Moorebank in 1970? I was at Casula in 1970, doing an Engineers course at SME, along Moorebank Rd, but I don't remember ever hearing or seeing a Mustang in the air.

     

    Maybe we were too busy making earthmover noise, and building Bailey bridges, and floating MK3 ACCO's across the Georges River on pontoons, to take any notice of Mustangs flying overhead??  006_laugh.gif.d4257c62d3c07cda468378b239946970.gif

     

    Pmccarthy - Re VH-IVI - the pilots name was Ray Whitbread, not Whitebread. It appears the previous owner of IVI had a different opinion as to what caused Whitbreads crash - and it wasn't the canopy becoming detached - in his opinion, it was Whitbread who had released the canopy, trying to get out.

     

    After all, many thousands of Mustangs were built and flown under combat conditions and detachment of the canopy was not something that was a known Mustang problem, nor even mentioned in anything I've ever read about them.

     

    Page 5 of the interesting article below, gives the previous owners opinion about what really happened to IVI and Ray Whitbread.

     

    http://www.saam.org.au/wp-content/uploads/2013/09/SAAM-Profiles-Mustang-CA-18-Mk-21-A68119-VH-IVI-v11-3Jul16.pdf

     

     

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  14. Given the investigation into the delegating of part of the certification from FAA back to Boeing I think it will be some time before the whole sad affair is resolved. The US will be keen to get it done quickly as they won't want Boeing crippled by this. It is like GM was during the GFC, Too big to fail. The rest of the world though will be somewhat more cautious I suspect. 

    There's little chance of this damaging fiasco crippling Boeing in the short-term, it's more like a bad mozzie bite to them. They are valued at USD$212B, and their profit last year was USD$12B.

     

    It's estimated the cost of compensation to Boeing for the fiasco, will be limited to about USD$2B, so it's just business as usual for them, albeit with a hiccup.

     

    The longer term damage whereby many airlines have incurred severe financial damage by not being able to use their parked-up 737 MAX's, is something that has yet to be played out.

     

    I'm not sure how those airlines will be able to recover any of their losses, if at all - and this could mean bankruptcy for some of those airlines, if Boeing don't get those parked aircraft, up and running again, fast.

     

     

  15. I'd really like to know how you go about harvesting ferret urine on a commercial scale? - in volumes enough to squirt down a hundred rabbit burrows?  In my experience, the rabbits would just promptly dig some new burrows!

     

    In a previous life, I was an agricultural earthmoving contractor, with several Cat D7 dozers. A regular job I carried out for farmers was ripping rabbit burrows with the D7 rear-mounted ripper.

     

    It was very satisfying, running over rabbit burrows with a 25 tonne crawler tractor, and then dropping the 3-shank ripper in, to it's full 800mm depth, and turning their cosy homes into a wasteland of soft dirt that collapsed onto them - and which they almost never managed to dig their way out of.

     

    One farmer, who was obviously consumed with rabbit hatred, told me how he had a pile of enduring rabbits living in a heap of dirt and sticks and trash - and one warm day he set fire to the heap.

     

    He was also obviously a vicious, vengeful bastard - because he said, the rabbits tried to flee the flames, and he reckoned he enjoyed the sound of squealing rabbits on fire, dying in the paddock by the dozens.

     

    I guess the RSPCA would hang him by the gonads if they found out he did that, to lovely harmless little furry critters, today.

     

    It's not until you see the total destruction of the Agricultural areas of Australia, by overwhelming numbers of rabbits, do you get an idea of the depth of rabbit hatred amongst farmers.

     

     

     

     

     

     

     

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  16. Just got sick of flying? They broke up? Seems like nothing has happened with them, as regards on-line activities, since about Oct 2017.

     

    But there is a reply to one comment on their blog, by Alicia in Jan 2018, so they must still be around.

     

    Maybe they just had to go back to the corporate grind for a while, to pay for more flying adventures??  003_cheezy_grin.gif.045ea30218c055c2781fc6f7d18be527.gif

     

    http://australianadventure.net/blog/2017/04/28/episode-10-unexpected-flight-home/

     

     

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