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You are correct that the cylinder heads were changed to read coolant temperature not CHT. But Rotax do refer to this as coolant temperature, not CHT. If you are measuring coolant temperature the limit is 120C. Aircraft builders/manufacturers may or may not have made the change correctly. The history as I recall: Originally, the sensors measured CHT and the limits were 150C for 912 and 135C for 912S. This was a bit hot for the coolant (particularly 150C), and coolant could boil in the heads, which was bad because a layer of vapor prevented proper cooling so it got even hotter and you had a vicious circle i.e. normal behaviour when a water cooled engine overheats. Rotax recommended waterless coolant which didn't boil at normal operating temperatures Unfortunately, the waterless coolant had less cooling capacity so engines ran hotter Rotax changed their recommendation back to conventional coolant, but required either measuring coolant exit temperature as it exits the engine, or change the CHT limit to 120C. Rotax introduced new heads which measure the coolant temperature, with a coolant temperature limit of 120C. So the operators manual now lists CHT limits for engines with the old style heads (135C/150C CHT and 120C coolant), and coolant temperature limits for engines with the new heads (120C). So you need to figure out which heads you have and what you are measuring to know which limits apply.

Coolant exit temperature is as it comes out of the engine i.e the maximum coolant temperature reached. It is to ensure the coolant isn't boiling in the engine. CHT max is 150C for the 80HP but only 135C for the 100HP. My understanding is that this is for detonation margin with the higher compression.

Industry is never going to buy nuclear power, it's too expensive. Already, solar and wind are producing enough power that prices sometimes go negative at times of high production (during the day, when solar is producing and happily industry tends to be most active). Industry would rather build storage and buy cheap power (or even be paid to take it) than buy expensive nuclear power. Storage for industry has the advantage that it doesn't need to be portable, so weight and size are not such an issue. Cheap materials are more important than e.g. low weight. The nuclear industry knows they have missed the boat. They are desperately trying to convince people they need their expensive power so they don't have to write off their investments.

The aerodynamic coefficient IS the measure of the power required to "push the air out of the way" or move through the air. If you are measuring air resistance it is the useful measurement. For aircraft it is relatively simple... remember all that stuff from theory about best rate of climb, best glide, minimum sink, the drag curve and the changes with weight? All the information is already known. And we use most of the energy already - we don't generally have air brakes so there isn't wasted energy to capture from regeneration. The problem is the increase in power required to keep you aloft as weight increases. That's a weight squared relationship, so things get worse quickly as weight increases. And battery chemistry has hard limits on the energy that can be stored per kg for each combination of elements. So I am not optimistic about useful electric aircraft.

These seem way too high. If you use an engine BSFC figure of e.g. 250g/kWh, 35 kW at 100km/h is equivalent to about 12litres per 100km. Probably half that is more common. 6 litres/100km gives 17.5 kW at 100km/h and 17.5 kW/h for 100km. Pretty close to the 16 kw/h for 100km originally stated.

The big challenge for EV infrastructure will be managing peaks e.g. holiday weekends where everyone wants to travel. I've seen petrol stations on the Hume with 16 pumps busy plus 20-30 cars queueing. It's going to be a while before electrical infrastructure can cope with that sort of peak. On the other hand, maybe many people will charge overnight at their accommodation rather than stopping along the highway.

It's important to make the distinction between plug in hybrids and e.g. the Toyota hybrids. Toyotas are basically ICE with regenerative braking (and some related optimizations). They have basically no range as an EV. The battery is very small, but there isn't much extra weight e.g. they quote about 60kg extra weight for the hybrid Kluger. Plug in hybrids are the worst (and best) of both worlds. You have both a significantly sized battery and ICE to maintain. However, you can charge at home covering most people's common short trips, while using the ICE for longer trips and not being dependent on charging infrastructure.

That specific vehicle, but the article you quoted basically confirms what I was saying: Hot hydrogen can be applied in a hybridised arrangement to leverage existing electrification technology, a bonus for Toyota as the world’s largest producer of hybrid drivetrains.

Surprisingly well. Unless it is dead flat they harvest energy on the downslopes and use it on the upslopes and the flat. It's not just the energy from friction braking they save, but also engine braking i.e. the energy to spin the engine when you lift off the throttle. Toyota has decades of investment in hybrid that will become worthless if the world moves to fully electric vehicles. The focus on "hot hydrogen" seems like an attempt to steer things in a direction where their hybrid technology is still useful. You can be sure that their hot hydrogen ICE would be a hybrid, just for the efficiency factor. Toyota sells huge numbers of hybrids across most of their range. They can't build them fast enough to meet demand. If the world moves away from ICE, they become the leader in a technology that no-one wants anymore.

Tell that to Toyota, or any of the electric and hybrid vehicle manufacturers. Regenerative braking is key to their efficiency. Friction brakes and Jacob brakes both convert kinetic energy to heat and dump it into the environment where it can't be recovered. Regenerative braking stores it in the battery where it can power an electric motor to convert it back to kinetic energy. It's not 100% efficient of course, but a lot better than the 0% of regular brakes. However, there's not much scope for regeneration in an aircraft because most of the energy from a descent is used up in staying aloft and overcoming drag. You only have excess energy available if you are at zero power setting and you want to descend faster without gaining speed. That really only applies to aircraft with speed brakes or on final approach to landing. Most of the rest of the time you will be using engine power i.e. no regeneration available.

The student pilot is a red herring. The tug pilot said he was going to stop before the crossing runway, which would have been clear of both the taxying and departing aircraft. The problem with that is that it's a gamble that you won't have to go around, for any reason. The taxying aircraft wasn't a problem, the conflict was with the departing aircraft. Maybe we need to recognize that LAHSO style operations are a bad idea at GA/uncontrolled airports. I know it's pretty common to end flight reviews by pulling the power on downwind for a glide approach to the cross runway, with a broadcast that we will stop before the intersection. It isn't meaningfully coordinated with the traffic on the other runway in case of a go around. Maybe that's a risk that we shouldn't be taking.

I'm interested to hear anything on-topic, but so far no-one is posting anything more.

Demonstrated by who? The air is the same in Europe and Australia. The only way to do this would be to have a totally different wing. (We are talking CAS, not the number you see on the air speed indicator.) Well what do you know... stall speed is 35.8 knots at 580kg.

I think your stall speed figures are a little rosy, going by the POH on their website. You seem to be confusing IAS and CAS and ignoring weight. They list a stall speed of 28 knots IAS, which is 31 knots CAS. Adjust for weight and the equivalent speed would be 36 knots at 600 kg. Certainly good, but calling it 27 or 28 knots is an unreasonable comparison. For listed cruise speed Atec seem to be a bit unclear whether its TAS or CAS or IAS. It seems to be TAS, although from their airspeed correction table 134 knots IAS is 124 knots CAS so IAS ends up close to TAS at a few thousand feet anyway...

Front loaders are a bit different, they have gravity on their side to stay put, and can even slow down and use gravity to redistribute the clothes when they are out of balance.

My understanding is the "wobble" from imbalance causes the beads/mercury etc to collect on the light side, reducing the amount of imbalance. It can never bring it to perfect because if it was running in a perfect circle the material would be distributed evenly and wouldn't change the balance, but it will be better. Washing machines apparently use the same principle to balance their spin - a liquid filled balance ring at the top of the tub.

I think the blame most likely lies with the operator. But the lawyer's job is to get the best result for their clients, where the best result is the largest pay out possible. One organization has folded, and I suspect the other one doesn't have a large insurance policy. So the lawyers move to the next in line who has deep pockets and/or a sizeable insurance policy, and try to convince them that a settlement would be better than risking a court case. Most public liability cases are a game of lawyer chicken, where neither side wants to go to court, but wants the other side to give in to avoid it.

"One of their arguments is that the manual lacked instructions on how to maintain the plane’s centre of gravity while people were moving in the plane." I found a GA8 parachute operations supplement online dated 2009. Under Weight and balance it says: no more than five (5) parachutists may congregate aft of the forward edge of the cabin door exit with no more than three (3) outside of the aircraft. ... Parachutists inside the cabin should remain as forward as practically possible. Seems pretty explicit... I'm not sure what else they could do. More likely, the parachuting organization ignored the instructions in the manual. I suspect that happens a lot. Another similar case: https://www.avweb.com/aviation-news/pilot-says-skydive-king-air-spun-after-c-of-g-exceeded/

Your main problem will be faster traffic on final as you say. Shouldn't be too much of a problem unless its very busy. Just make sure you look for other aircraft on final while you are on base. Don't focus on the runway. That goes for everyone really - for a left hand circuit you should be checking to your right on base and before you turn final. You have a lot of flexibility by adjusting your circuit size. I was doing circuits (1000') in a Gazelle one time, and a C172 took off right behind me. I don't like a faster aircraft too close behind me, so I kept my circuits fairly tight. After 3 circuits I was turning base as they were turning final. 😀

I don't think that's true. Operations at uncontrolled aerodromes usually work pretty well. Some pilots are uncomfortable though. The advice on operating used to be fairly prescriptive, but CASA have been dialling it back. I don't think that's a good thing. However, most people still do what CASA used to proscribe, e.g. calls when turning base. Speed limits don't really make sense because aircraft need to operate at different speeds. There is the option for fast aircraft (e.g. jet/turboprop) to do 1500' circuits instead of 1000'. Otherwise, adjusting the size of the circuit works pretty well to account for different speeds. Lanes of entry (especially the approach points at Class D airports) make no sense. The idea is to work out where other aircraft are before you try to be in the same place. Having people all fly to the same place then make their radio calls is exactly backwards. I'm amazed we haven't had more collisions at the Class D approach points. Goes to show how well the big sky theory really works I guess.

There is a big difference between see and avoid enroute and in the circuit. The circuit is designed so you can see other traffic. They are in predictable places so you know where to look. Most flights I end up sharing the circuit with other traffic. I know you can see aircraft at circuit distances. It's not a tiny dot in the distance. No-one would claim I have superhuman eyesight - for a start I wear glasses that make everything 10% smaller (minification) so if you're not wearing glasses for short sightedness you have a 10% advantage on me. (One of the traps with traffic displays is you start looking for an aircraft when it might be 5 or more miles away, when it really is a tiny dot in the distance or invisible. But circuit distances are generally less than 2 miles.) This is pre-solo level stuff (pre area solo for joining the circuit). Seriously, if you have trouble, go out and do circuits with other aircraft. Follow the aircraft in front and learn where to look for them and how to keep track of them. Don't be the guy they warn the students about in the clubroom because he cuts everyone off and has no idea where other aircraft are.

Yes, that's the way to do it. ADSB is great away from the airport, and when you have other aircraft inbound. In the circuit you should know where to look - although it can take a few seconds to spot someone e.g. on base against ground clutter. Joining, I usually overfly at 1500 (or 2000) because it gives a birds eye view to assess traffic, and you can do a faster or slower descent to fit in.

Behind or above you or below you can be impossible to see. Circuit procedures are designed to give you a chance to see and sequence while random variations in flight paths are working for you. The closer you get to the runway, the less variation there is and the more probability there is of a collision. IFR aircraft fly routes, altitudes and waypoints much more accurately so there is a higher probability of collisions away from the airport. That is why IFR need ATC separation (and why Australia's IFR in G is crazy...) It's also the problem with straight in approaches - the extended centreline puts aircraft close together before they have had a good opportunity to see each other.

Sorry to be that grumpy guy, but what is it about "visual" in visual flight rules, or "see" in (alerted) see and and avoid that people don't understand? We fly a circuit so that aircraft are in predictable positions so you can see them. If you take off or do a touch and go and there is an aircraft on crosswind, and you then have a conflict on base you have cut them off. It's your job to see them and maintain separation. It doesn't matter if they do a larger circuit than you'd like - you still need to see them and maintain separation. If there is an aircraft on downwind and you want to join the circuit, you need to see it to make sure you are clear. If you can't see it, you need to wait until you can or make sure they are clear e.g. they report turning base. You can't just continue on and hope for the best. If there is a conflict on downwind or base, you cut them off. If you only heard them turn base, you still need to see them on base/final to be sure of separation for your own base and final. Seeing other aircraft in the circuit is a skill that needs to be learnt and practised. Go out and do some circuits with other aircraft, and learn where to look and what they look like. Accurate height is important so you are looking for other aircraft against the sky rather than ground clutter. If you still can't spot other aircraft in the circuit, maybe you need to assess whether your eyesight is good enough for flying. I know some people keep driving even after they are legally blind - I'm sure there are also people flying whose eyesight isn't what it once was. Harsh truth - sorry. This is what worries me about the discussions of traffic displays - people talking about using them as a substitute for looking for and seeing other traffic in the circuit.

The biggest problem is you have to run the prop and engine at the same speed. To fast for a prop (even if you like the sound of the tips approaching the sound barrier it's not efficient) and slower than ideal for an engine. So the engine has to be bigger to run at that slow speed, and therefore heavier. Attempts to save weight can compromise reliability. Another problem is that the crankshaft is susceptible to damage with the propeller bolted directly to the end. Have a look at Lycoming's guidance for when a tear-down is required. Any damage requiring repair of the propeller, whether the engine was running or not... Yes, the propeller acts as a flywheel, but it's a very springy flywheel and springy flywheels are probably not ideal either. With the propeller bolted rigidly to the crankcase the whole system is a spring, from the tips of the propeller through to the other end of the crankshaft. The engine designer has to consider the vibration, but can't know the exact characteristics of all propellers that might be used. I think the important length measurement for a crankshaft is the zig-zag length through all journals - not just a straight line from front to back of the engine. I'm not sure how a flat motor crankshaft compares to others, but the 2 pistons at 180 degrees looks like it creates a very long section of crankshaft between main journals - especially in an engine with a long stroke. Simple? Definitely. Good? I'm not so sure. It looks more like it's cheap and adequate rather than good. Even when these engines were designed they knew how to build better.