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UNICOM isn't a controller. UNICOM just provides information. Pilots are still responsible for their own separation.

The location is supposed to be the last thing in the call. Probably doesn't make much difference in practice, but if you are going to pick on other peoples calls you should make sure your own are correct.

China has apparently banned exporting it so that it can be used in fertilizer in China. I hare to think of the urine consumption required by a truck to replace it!

Yes. China has banned exports of urea (80% of Australia's supplies), and there is a global urea shortage. As a result, there are reports that Australia will run out of Adblue in February.

Meanwhile, there are reports that Australia will run out of Adblue in February. Maybe those electric trucks weren't such a bad idea.

Practicable: able to be done successfully, possible. So you need to prove that it was not possible to fly at the correct cruising level. Not that it was uncomfortable or unsafe - that it was not possible. It would usually be possible to fly at 2500 (a specified cruising level) when 4500 was not possible, even if it is e.g. turbulent. The fact that it might be only 1500 AGL and not as safe as flying higher doesn't come into it. Also, it appears that it is technically illegal to give a 1-200 feet buffer below the lower level of CTA. There are many places around Melbourne where the rule requires you to cruise exactly at the bottom of CTA (or below 3000MSL/1500 AGL).

Not mandatory you say... 91.275 Specified VFR cruising levels (1) The pilot in command of an aircraft for a VFR flight contravenes this subregulation if, during the flight on a track, the aircraft is flown at a cruising level that is not a specified VFR cruising level for the track. (2) Subregulation (1) does not apply if the aircraft is in uncontrolled airspace and any of the following apply: (a) the aircraft is below 3,000 ft above mean sea level; (b) the aircraft is at or above 3,000 ft above mean sea level but below 1,500 ft AGL; (c) it is not practicable for the pilot in command to fly the aircraft at a specified VFR cruising level for the track; (d) the aircraft is a glider in soaring flight. (3) Subregulation (1) does not apply if: (a) the aircraft is in controlled airspace; and (b) air traffic control has given the pilot in command an air traffic control instruction, or an air traffic control clearance, to fly the aircraft other than at a specified VFR cruising level for the track. (4) A person commits an offence of strict liability if the person contravenes subregulation (1). Penalty: 50 penalty units. Note: A defendant bears an evidential burden in relation to the matters in subregulation (2) or (3) There are interesting intersections with cloud clearances... if there is cloud below 5500 it is effectively illegal to cruise westbound above 3000 MSL/1500AGL.

The number of people who actually need that is a small proportion of the population. By the time that becomes an issue, EVs will be a the vast majority of the market. Globally, the current demand for EVs is far greater than the supply. Why would you sell cars for 26K when there are people who will pay 40K, 50K, 75K+? As manufacturing moves away from ICE and supply starts to meet demand, prices will fall. In theory EVs should be cheaper because the engine and transmission is far simpler. Many people are already saying they will never buy another ICE car. They are either driving electric cars, or waiting until they become more available. That trend is only going to accelerate.

The ones on my engine look something like these: https://au.rs-online.com/web/p/spade-connectors/6805921/ positive lock female spade connector looks like a promising google search

I saw a figure recently (I haven't tried to do the calculation myself) that "20% of Australia's grazing land covered with solar would provide the whole world with carbon-free energy". Of course, a) that's a lot of land and b) transport and storage is still a problem but the energy seems to be there. Mike Cannon-Brookes is aiming to export renewable energy from the Northern Territory to Singapore via undersea cable - helping countries without Australia's land area to meet renewable energy obligations.

The amount of fossil fuels being burned and the rate of change has increased markedly in the last 50 years. So it doesn't matter whether you pick a baseline of 50 years ago or 250 years ago, the change is very similar because most of it occurred in the last 50 years.

That's not how it works. 1.5 degrees is the average over the globe, not what is experienced in particular locations. Weather is driven by the heat and water vapor in the atmosphere. A warmer atmosphere has more energy and more water vapor, and weather in general is more intense. Storms are more powerful, winds are stronger, rainfall is more intense. Some places will be much hotter. Some places may even be colder at times because stronger winds are bringing colder air from the polar regions. But when that happens, the warm air goes to the polar regions which end up much hotter. The average is still higher. The big problem for humanity with climate change is not the absolute change in temperature. The big problem is that civilization relies on so much immovable infrastructure (cities, transport, water supplies etc) that has been built based on current weather patterns. If we were nomadic and could pick things up and move them when the weather becomes a problem, it would not be such an issue. We can't.

If you want to disagree with something, perhaps you can tell us what? Knowledge isn't worth much if you don't put it out there to test.

The shaded area is above 27" manifold pressure. Manifold pressure is reduced when you close the throttle. The reference to 3500 feet is because the air pressure reduces as you climb, so the manifold pressure possible at full throttle reduces. It is absolutely permitted to close the throttle and reduce RPM and cruise at a lower power setting because your manifold pressure is reduced by closing the throttle. The relationship between manifold pressure and rpm is set by the propeller. If you have a constant speed propeller, you have to manage manifold pressure to make sure you don't exceed allowable manifold pressure for the RPM. If the propeller is fixed pitch or ground adjustable, the pitch determines whether the engine is overloaded. If you are at less than 5200 rpm at wide open throttle you are lugging the engine (too high manifold pressure with too low rpm). In that situation Rotax recommend you close the throttle and reduce RPM by at least 100, because that shows that the manifold pressure has been reduced. It's not lugging at a lower rpm because with a fixed pitch propeller the load from the propeller reduces. They have provided a number of points on the chart: 5500 rpm 27"MP - max continuous power 5000 rpm 26"MP - 75% power 4800 rpm 26"MP - 65% power 4300 rpm 24"MP - 55% power Without a manifold pressure gauge we don't know the exact power setting, but it's pretty safe to assume if you get 5200+ at WOT at climb speed with a fixed pitch prop, manifold pressure will be OK in cruise. If you're only using 13-14 l/h at 5200+ you should be well below 75% power so well below 26" MP. 75% power fuel consumption is about 19l/h. 14 l/h should be around 60% power. With a variable pitch prop you would probably be better at around 4700-4800 rpm. However with a fixed pitch prop and a faster aircraft, 5200 minimum at WOT in climb means higher rpm at cruise speeds.

It doesn't show that at all. It has e.g. settings for 55% power cruising. What it shows is that 5200-5500 are the recommended/required rpm for full throttle at low altitude.

Can you provide a reference to the recommendations in the manual? I can't find anything. I have heard for many years that the 912 should be run at over 5000 rpm but I have never seen anything official from Rotax. It seems as likely as not to just be folklore. Exactly what problems are people anticipating running < 5000 rpm (assuming unleaded fuel)? Is there any real decrease in engine life?

You didn't use 55l/sec in your original calculation. You used 5.5l/sec. True, but it gives a reasonable point to start from. If you really want a more accurate answer you can start refining various figures but there's probably lots of factors unaccounted.

I think that is too low - should it be 55l/sec? ~40C doesn't sound unreasonable, that would presumably be measured as a drop in EGT.

Cars have a knock sensor that will retard timing if detonation is detected. If they have to retard timing from the optimum value due to low octane fuel, higher octane will give better economy. If they can run at the optimum timing on the lower octane fuel (i.e. engine design) they get no benefit from higher octane. Also, some of the 98 octane fuels claim to be "denser" i.e they need a leaner mixture. A car with an O2 sensor will adjust the mixture and use less fuel. If you have a mixture control in your aircraft, you might also use slightly less fuel. A carb without manual mixture control i.e. Rotax, Jabiru will use the same amount of fuel but run slightly rich.

Before V1 you need to be able to abort the takeoff and stop safely in the remaining runway. After rotation the task is fundamentally different, so V1 cannot be higher than Vr. If you don't plan to rotate at "Vr" it is not Vr. I was thinking about when V1 might apply in a single. There are problems where the correct thing to do is continue the takeoff so you could say V1 does apply. For example, if a door pops open in the takeoff roll. Early in the takeoff roll, if a door pops open, cut the power and come to a stop, no problem. If the door pops open as you rotate, cutting the power and trying to stop on the runway is a recipe for a broken aeroplane. Better to continue the takeoff, and do a normal circuit and landing. Or if the runway is really long, maybe you can stabilize the aircraft, reduce power and land straight ahead. But again that is different to an aborted takeoff before rotation. If the runway is short, e.g. you have a 500m runway and calculated a 400m takeoff distance, at some point before rotation you are committed - you probably can't stop in the remaining runway. At that point, if the door pops open you need to continue the takeoff. That is your V1 - even if no-one ever calculates it. There is no reason for V1 to exist except "what it is for". If the definition doesn't quite capture it there is a problem with the definition. "What it is for" and how it is used are the whole basis of V1. V1 is most critical when the runway length is limited. Yes. on longer runways V1 can be equal to Vr and you can abort the takeoff any time before rotation.

The point of V1 is that it is a pre-made decision about when you will continue the takeoff instead of stopping in the event of an emergency e.g. engine failure. It is there so you don't use up runway and options while you wonder should I stay or should I go? We don't use V1 in smaller aircraft For the case of an engine failure in a single, V1 doesn't exist. Jets etc. are required to be able to stop on the runway from V1, because running off the end of the runway after an engine failure is considered a bad thing. For smaller aircraft, people don't really care e.g. your takeoff charts for runway required do not include an allowance for stopping distance after a rejected takeoff. If it's a planned speed for rotation, aren't you using a lower Vr?

That's never supposed to happen. The theory is you detect the problem before V1. At V1, you should be able to reach Vr and fly away even if you lose an engine. This is factored into the aircraft design. If you need to be able to stop from Vr you potentially need a much longer runway or much more restrictive limits on weight.

If you don't rotate at Vr, it's not Vr?? V1 is only applicable to multi engine aircraft. It's the point after which you can't reject the takeoff, either because there is not enough runway to stop or you have already begun to rotate. Performance calculations ensure that at V1 you have enough power to continue the takeoff even if you lose an engine. If you don't, you have to adjust performance e.g. reduce the aircraft weight. The ability to continue the takeoff or stop on the runway after engine failure is only a requirement for larger aircraft. For smaller twins on shorter runways it may not be possible. I'm not sure where the cutoff is but it definitely applies to the jets operated by the airlines. (Not a multi engine pilot myself, happy to be corrected...)

Rejecting a takeoff after rotation would be considered a different kind of emergency... it gets significantly more difficult.

FAR part 103 is totally different to anything we have here. It is for single occupant, <254 pounds empty, <5 gal fuel capacity, 55 knots max speed and 24 knots stall speed. As I understand it, no license or training is required. It is probably closest to the pre-AUF ultralights in Australia. Not really what anyone is talking about.