Ian

This sound a bit conspiracy theoryish to me. I'd suggest that you read up on what the IPCC is https://en.wikipedia.org/wiki/Intergovernmental_Panel_on_Climate_Change and understand it's funding model. It paid for by Governments and the payments are voluntary. It's reports are based upon good science, not conspiracies or some special club's agenda. Look I've worked in an around Government agencies for decades and they struggle to tie their shoe laces, even given an instruction book. Yes the "Club of Rome" is an organisation however it's not a particularly potent lobby organisation. It reflects a point of view but not a particularly great one or one backed by rigourous modelling. https://en.wikipedia.org/wiki/Club_of_Rome they aren't particularly influential There is no "Climate change agenda", there is a climate change problem. Climate change is a real problem and it is based upon very simple science with some appalling outcomes, in many way the analogy to the recent Chinese booster launch stage coming back down recently is a good one. Just because we can't predict where it will land doesn't mean it won't be coming down. That sucker is coming down and it's based upon very simple maths which a high school student can do, similarly climate change is based upon very simple maths, however predicting the exact outcomes is very difficult. The key thing is that this lack of certainty is actually worse https://www.abc.net.au/news/2022-07-28/chinese-long-march-booster-rocket-fall-earth-china-doesnt-know/101276380 Shorthaul jet travel may have had a significant impact on the operation of some mines however that doesn't mean that it is a sustainable business model if you factor in the cost of emissions. Once you do other options might present themselves as more attractive. Even minor efficiency gains like turboprops start to add up so if you want to invest in transport they'd be the way to go. Look I want to do things which have an extravagant energy budget however I'm smart enough to know that fossil fuels are bad. They're extremely handy and we've 120 years of optimising processes to make stuff from them. If you look at the four pillars of modern society as "cement, steel, plastic and ammonia" we currently make them all from very old sunlight in the form of fossil fuel, getting away from that will be incredibly hard and expensive. Look while I think that wind and solar have a place in the overall energy solution personally I don't think that it is a viable solution for more than about 15% of our electricity grid needs. We need clever people making good decisions on what technologies to base our economy on which don't emit greenhouse gases. We don't need lazy thinking blaming it on a "conspiracy theory". I read up on the costs associated with ammonia production via solar and wind and it's pretty ludicrous. For example a best case scenario gives you about a 20% efficiency ignoring the fact that you might need to transport it, and the fact that nobody yet has a power generation turbine which can run on ammonia so you'd need to split it back into Hydrogen making it even less efficient, ignoring the fact that burning ammonia makes 100x the NOx emissions of natural gas. Also ignoring the fact that you'd want to be running the electrolysis unit as 100% rather than intermittently and the fact that you need to run the Haber-Bosch process continuously or otherwise it damages the catalysts.

I have a pretty good understanding of what science actually says in this area. While there is a lot of the non-science chatter in the popularist mediums (this one included), proper journals actually publish good material and I suggest you acquaint yourself with these sources of information. Wikipedia too is a good source of information. Contentious issues tend to be moderated by people who understand and attempt to provide a viewpoint which reflects consensus. Rather than argue I'll simply point to the following. Firstly read the wikipedia article on the guy. While he worked for a Government department he wasn't the go-to guy, he was an under-secretary. This is a member of the management team but not a head-honcho. The secretary is the go-to person. https://en.wikipedia.org/wiki/Steven_E._Koonin Secondly read a couple of rebuttals in either a respected popular science rag such as Scientific American which has had articles written by luminaries such as Einstein https://www.scientificamerican.com/article/a-new-book-manages-to-get-climate-science-badly-wrong/ Another nice rebuttal is provided by one of his previous PhD students, who actually liked the guy https://yaleclimateconnections.org/2021/05/a-critical-review-of-steven-koonins-unsettled/

The statistics that we're presented with often don't tell the real story of actual risks. For example young people are over-represented in the driving statistics fatality rate. However when you base your statistics on actual risk per unit of exposure ie the amount of travel that people actually do, the high risk drivers are the elderly. Essentially young people drive a lot and they tend to drive with full cars. People older than 70 don't drive near as much however they're over-represented in the accident statistics per unit of travel. And yet in Victoria you now require something like 200 hours or 5 weeks of 9-5 driving to get your provisional license. And yet there are no controls of the actual higher risk group. Another ignored risk is that young drivers generally get better over time and older drivers get worse.

This might explain why our neighbour had to intervene and get their fathers license removed in Victoria. Can't say that I think that its a great policy from a safety point of view.

Lion or Tiger?

Which DC's did you buy? Some of the higher end headsets just felt a bit plasticky, fragile and cheap despite the price tag. It's a pity that they don't publish measured attenuation figures, or if they do I'm not aware of them. One thing to considered with the ANR is the type of connectors to get with the headphones so they can receive power from the plane.

If you have the gift of the gab, truck weighing stations have set of weights calibrated against the National Measurements Institute standard weights. That way you could calibrate your standard bathroom scales.

Really enjoying the thread and seeing the different approaches being used. Would it be possible for those who've built or had hangars built to give the dimensions, floor type and costs. (probably the approximate year as well)

What's the advantage of noise cancelling and earplugs. Wouldn't it be simpler to buy earphones that attenuate the sound more? A combination of https://www.amazon.com.au/Professional-Safety-Decibel-Defense-PROTECTION-GUARANTEED/dp/B01BEENYCQ and earbud mikes might also be more effective if it floats your boat as it would combine the best quality of sound with an un-distorted sound feed. I'm not 100% sure what you're saying. Do you wear passive foam plugs under your headphones? If that was the case your headphones would need to be louder to overcome the passive plugs and thus would sound louder and even with foam plugs with attenuate different frequencies at different rates. The whole wearing a facemask and earplugs when sleeping never really lit my fire so I can't say I'm a fan. I wear ear protection when I need to but my house is pretty quiet of a nighttime. However if I slept with someone who snored I might change my mind 😉 https://apps.dtic.mil/sti/pdfs/ADA624086.pdf There's a good piece of research on this however it's a pity that it didn't include the David Clark One-X in the mix as I'd be interested to know how much passive attenuation they provide. I suspect that they'd pay more attention to the passive attenuation than other brands but that's just a guess.

It's a pity that the Government didn't go through with the Australia card years ago. Rather than try to force it down peoples throats it could have been a smartcard that combined all forms of Government identity in a secure element. The current approach of putting credentials on a phone is a bit dumb. A phone is just a computer complete with all the associated security vulnerabilities. A large chunk of the current medicare rorts would disappear if you had a simple tap and go style approach to medicare charges.

I think that you'll find that Australia is importing most of its Doctors https://www.racgp.org.au/health-of-the-nation/chapter-2-general-practice-access/2-2-gp-workforce with 51% being foreign trained. So basically Australia takes scant medically trained staff from countries with major health issues which I find a bit wrong and think that we should be training far more doctors and specialists through the public purse. I know that there are lots of people who still want to study medicine and miss out by a couple of marks. It would also be reasonable to make science, engineering and computing degrees free so we have a workforce with management who are comfortable with maths and building things, because currently this isn't the case. It would also mean that might have a workforce who can look after our rapidly aging population both from a medical and economic perspective. I don't mind paying for things that are reasonable such as health checks, medicals etc, however a requirement for multiple different types of medicals is a bit silly. Also it is reasonably to take away a privilege if they pose a danger to others. However real risks should be apparent and it should be done efficiently. Unfortunately what we have now is not particularly efficient or risk based. It would be nice if there was a single medical test for non-commercial vehicle operations and a single test for commercial operations. If someone is to unfit to operate a plane then then they probably shouldn't be driving a truck or in command of a ship either. Does anyone know an overweight truck driver? https://www.hsph.harvard.edu/news/press-releases/truck-drivers-sleep-disorders-crashes/ https://www.abc.net.au/news/2020-05-08/canberra-truck-driver-with-sleep-apnoea-sentenced-to-jail/12228490

Or just imperial metric conversion. https://en.wikipedia.org/wiki/Gimli_Glider Aviation reintroduced me to the joys of the imperial system. Pounds, feet, gallons, quarts, knots, it's like learning how to write Chinese hanzi after using an alphabet. Both are pretty and interesting but not particularly functional and should have gone into the historical dustbin years ago. But inertia rather than common sense will keep both in use and people fighting for their continued existence. For giggles look up how to type on a Chinese keyboard, or how to calculate the energy absorbed by the braking system of an A380 which lands at 145knots or 75m/s weighing 575000 kg (633 US tons). By the way the formula for metric is 1/2mv2 and you're done. Would you answer in imperial units in BTUs, calories or "refrigeration tons"

There are some who swear by them, mostly by those who fly in the stormy areas of the US. The key discriminators are that they're real time, sometimes register small discharges in turbulent air, and can show buildups prior to radar. I originally dismissed them as old tech but I'm not as sure anymore.

Hi All, Just wondering about the utility sferics devices such as stormscopes and their kin in Australia especially given that the year ahead is looking particularly wet again. It's interesting trying to correlate what you see on BOM with realtime strike activity on lightningmaps.org on especially in those regions not well served by weather radar. Not that I'm advocating flying into bad weather in any way shape or form, I just wanted to get some idea of their utility or lack thereof.

What is CASA's/Airservices resistance to allocating different frequencies for nearby airstrips? I've noticed that airports in reasonable proximity, using the same frequencies, often with similar sounding location names and with similar orientations can lead to those flying in the location ignoring "noise" from arriving aircraft. It just appears to be a bit backwards, especially when the solution which reasonably presents itself is to allocate discrete channels. The whole concept that it will cause more issues isn't really valid as there are different frequencies allocated already.

https://en.wikipedia.org/wiki/D-Motor I thought that it was a diesel but instead it was a flathead side valved engine. Can't say I'm a fan, but I like the sleeve valved engines https://en.wikipedia.org/wiki/Sleeve_valve I also like the Deltic engine which is a design which could push some good power to weight figures. https://en.wikipedia.org/wiki/Napier_Deltic

So from the above Diesel enjoys about a 10% advantage volumetric advantage over petrol and as you buy it by the litre that's pretty important. Diesel also enjoys a more efficient combustion process which adds another 20% or so advantage in terms of the efficiency extraction process. On a weight for weight basis you lose the 10% advantage however you still see the 20% combustion efficiency advantage of the diesel. Basically this is a thermodynamic limitation brought about by the much lower temperatures associated with petrol combustion due to lower compression. PV=nRT

Hi Yenn, think about it, there's a difference between the Otto and Diesel cycle, that's why they each have a name. Notice the differing shapes of the Pressure/Volume diagrams for ideal cycles describing both. The otto cycle requires an external source of ignition because the temperature rise due to compression becomes less when you throttle. A diesel always compressess a constant volume so the pressure rise is constant regardless of throttling. Rather than explain it read the below. https://en.wikipedia.org/wiki/Otto_cycle https://en.wikipedia.org/wiki/Diesel_cycle And here's an explanation of the difference from where I stole the diagrams. https://mechcontent.com/otto-cycle-vs-diesel-cycle/ Of interest is that the Otto cycle is more efficient than the diesel for a given compression ratio. The diesel cycle is practically more efficient because the higher compression enables a higher combustion temperature, laws of thermodynamics etc. From the wikipedia article.

Out of curiosity I'd like to know the performance numbers possible using a guiberson with a turbo and common rail.

I'm struggle to see your point or maybe I stated it poorly, by definition an engine which always runs with excess air is lean of peak and is a lean burn engine (ie diesel) and an engine which requires operation rich of peak is not (ie o360). https://en.wikipedia.org/wiki/Lean-burn It's a little more complex but in general it is true. Most Airplane engines are designed to use excess petrol for cooling and reduce detonation and may only be run lean as lower power settings. Modern car engines are not, demonstrating that this is possible not an inherent issue but a design choice. Diesel engines are essentially constant airflow, only fuel flow changes during throttling not airflow. So they operate to the oxygen rich side of stoichiometric. ie diesels normally operate at ratios between 17:1 and 70:1 however stoichiometric for a diesel is about 14.6 an tends to leave lots of soot in the exhaust due to the slower burn of diesel. The guiberson diesel from ww2 era was normally aspirated and designed as an airplane engine. It's power to weight was reasonable and it's efficiency was better than most modern cars including a prius. Turbo's can improve the power to weight and allow increases in power at the same rev range. Due to the combustion properties of diesel they tend to have a narrow rev range in which combustion can proceed efficiently. This is why forced induction, allowing more air to be pushed through the engine without changing the rpm is popular. Always is a very strong word, the guiberson has a power to weight of 0.781 kW/kg and the junker ju 205e 0.903 kW/kg and 0320 makes 0.99kW/kg in comparison. So generally works for me. I'm sure there's engines outside this rule and if I stated always someone would just prove me wrong. Also electronics are pervasive however they're on an inherent part of a diesels operation, however you can't design an otto engine without an ignition system.

To be clear a few of the advantages of diesel engines using diesel Better thermodynamic efficiency from higher combustion temperatures (due to higher compression) Higher energy fuel per litre 36.9MJ/l compared to 33.7MJ/l. Excess air ensures creates a leaner burn Max power occurs at RPMs that are suitable for propellers without reductions gearboxes Generally can run on Jetfuel (lubrication of the injectors can be an issue). Less flammable fuel Can be electronics free. ie no requirement for ignition. Some disadvantages are Power/Weight generally worse than petrol Power pulses tend to the stronger so items designed for petrol may endure. Limited track record Low temperature cloud point and pour point issues. Generally require turbos to bring them close to petrol engine performance. But I must admit I would be jealous if someone flew in an filled their piston powered plan with jetfuel.

It's a tragedy for all involved. All engines, airframes and pilots can fail, lets hope that there's a few lessons in the washup from this that we can learn from.

It's a manual process which is a bit unwieldy. The following article gives a bit of an overview of the principle and operation of a couple of commercial kits. https://www.aviationconsumer.com/maintenance/engine-dehydrators-engine-saver-prevails/ There's also the DIY approach https://www.pilotsofamerica.com/community/threads/engine-dehumidifier-diy.115754/ It's not an elegant solution by any means and your mileage may vary.

The key problem is that the airspace in the crankcase is moist regardless of whether you use water injection. Yes it may result in the exhaust stream being going through the block and existing via the breather beingslightly more humid however there is a significant amount of water either way. Steam passing over hot components won't condense so condensation occurs for a short period after starting and once the engine turns off and the crankcase cools. Condensate in the oil will evaporate after extended runs and exit via the breather. This is why systems which actively ventilate the crankcase with dry air after parking should reduce internal corrosion for planes which are kept sitting for extended periods.

It's from the "ATSB TRANSPORT SAFETY REPORT Aviation Research and Analysis Report" in 2007. It just wouldn't be possible for it to be incorrect. I think that both domestically and internationally there has been a trend towards experimental and light sport aircraft at the expense of the commercial GA streams. This report has some interesting facts. The best selling piston airplane manufacturer shipped 79 aircraft in the quarter. That's ~320 per year for the best seller worldwide. https://www.aopa.org/news-and-media/all-news/2022/may/19/not-all-pistons-remain-popular