Ian

It is easy to see trends in small information samples. Especially when change is forced. https://www.atsb.gov.au/publications/2018/ar-2018-058/ On top of this a number of aircraft engines are so marginal in the first place any change may push particular products over the edge. That being said I'd personally prefer to see ethanol free mogas made available by default at airports and adapt the airframe fleet. All other options are going to be costly as fuel companies will want to both maintain margins and recoup costs of a new product in a declining market. Also in regional airports the opportunity to have infrastructure that caters to both planes and cars might ensure that the fuel at least remains fresh.

The only way to make this work is a hard drop dead date. Planes which can run on available fuels will transition. Planes which can't will sell at a discount reflecting the cost of modifications STC etc. Companies will develop replacement fuels as the current market will disappear.

After watching his video on wheel pants I'm noting the flush sides on your wheel pants and the design of the engine cooling

I might have to buy a copy to take on my holidays as a bit of light reading. He died a few years ago and also designed the AR-6 https://en.wikipedia.org/wiki/Arnold_AR-6 According the the video he also built the Amsoil Racer so if anyone wants to go fast efficiently he's worth paying attention to.

Good approach to see. There's far too many people who don't ask fundamental questions for fear of looking stupid. Too many times I've left meetings to have people thank me for asking what "XXXX" meant and they've been involved with the project longer. Or possibly there's something wrong with those who actually ask questions 😉 One of the features in the video below which I found interesting was the lack of effect of a spinner on the speed of the plane. The simple high pressure zone in front of a blocking leading edge is actually a somewhat efficient shape. This makes me think that trailing mechanisms tend to be more effective.

I was wondering what the efficiency gains were and wikipedia just makes thing easy. https://en.wikipedia.org/wiki/Heat_exchanger#Flow_arrangement

Good advice. However if you can increase cooling efficacy it might be fun 😉 but more likely lots of heartache. The early turbo lycomings and continentals had lots of issues, and they are still prone to heat related issues. It's hard to get right. Does anyone know what the sodium filled valves for the rotax cost? https://www.rotax-owner.com/en/support-topmenu/40-uncategorised/658-si914030-914

I'd actually say that a supercharger is less desirable than a turbo for airplanes except for the back-pressure issue and you have some new issues. Turbo's operates very effectively at the reasonably constant loads that planes have compared to cars. The main reason that turbos have a reputation for more heat is simply because they can generate higher levels of boost and they run hot themselves. I didn't mean to put you off, if you're aware of the issues you cater to them in your design and build. More capacity is probably the simplest path to more power, however more power also increases heat load and it doesn't get you normalization at altitude. Rotax has released sodium filled valves which might be a reasonable way to extract a bit more heat. Also remember that as ambient density decreases, the required turbo size increases so size the turbo for your cruise altitude not sea level.

It's not only pressure drop. The air warms as it flows through the radiator, warm air cools less efficiently, so that back half of the radiator cools less efficiently, or you need to move the air through the radiator faster compared to a thin radiator which creates more drag. But I do like the mosquito as a plane, it's an example of material design compromise where the design leveraged the properties of the material rather than simply building a wooden plane like a metal one. Apparently this is a quote from Hermann Goring 'The British, who can afford aluminium better than we can, knock together a beautiful wooden aircraft that every piano factory over there is building, and they give it a speed which they have now increased yet again. What do you make of that? They have the geniuses and we have the nincompoops!'

A problem with most small planes is the lack of space and it's even worse in the engine bay. You're making compromises simply to make things fit. Cooling is really hard to get right. The aim is to accelerate the outflow as much as possible in the final duct recovering as much energy as possible. One of the things with these designs is that they tended to make the exit duct adjustable and not the inlet, higher pressure in the inlet duct makes the air spill around the intake so a static oversized inlet would appear to be OK. It's so difficult getting this right intially I'd be tempted to go down the variable geometry path as it would allow me to tune in flight rather than build 5 ducts before I found the best compromise. The other thing which people have alluded to it that the cooling requirements in climb are different to those in cruise so with any static design you're either over-cooling in cruise or cooking in climb. But it's another thing to build and another thing to manage in flight. These pictures are from another forum it's worth noting that the mosquito's design opted for a very thick radiator even though it's less efficient simply to make it fit. The P51

Turbos make engines more efficient by recovering energy from the exhaust gas however They increase the backpressure on the exhaust making valves hotter. They compress the intake charge making it hotter PV=nRT The turbine compressor blades transfer heat to the airflow as they're not 100% efficient You are generating more energy in a smaller space. This means more heat to dump Essentially it increases the heat load on the engine requiring more cooling. You can mitigate some of these issues with an intercooler however temperature remains an issue. Things like sodium filled valves also help with heat removal.

I like your confidence however I wasn't particularly optimistic based upon the views of the working group. From a quick review the thrust of the working group was to harmonize with NZ standards as the best approach and develop new standards.

Rather than argue about this I'd point you toward the article that I linked to and the section on "Classification of drag" being divided into 3 categories. Skin friction drag of stream flow. Drag due to eddying arising from separation of a stream from a surface. Drag due to expansion losses without actual stream separation. Points 2 and 3 are avoidable Thus the ideal system will be designed to to avoid stream separation or severe expansions To reduce the stream velocity over the cooling surface, and to reduce the external surface to a minimum. Even when following these principles it's hard to get the design right hence the design with maths and allow experienced people to fudge.

I'm not sure cowling pressure per se is bad for cooling. To create efficient low drag cooling you want small inlets and outlets and a large area of slow moving air across the radiator. Essentially the reverse of the below. http://hyperphysics.phy-astr.gsu.edu/hbase/imgmec/bernoul.gif High velocity airflow across the radiator is bad it equals lots of drag. Large thin radiators are more effective than smaller thicker radiators as the speed of the flow through the radiator can be lower for the same amount of cooling. Remember drag is proportional to v^2 Large inlets and outlets are bad (however you need them large enough to provide the requisite heat flow) and generally it's more effective throttling the outlet. This means that the additional heat you add to the flow can do work (but not really at the velocities we've talking about) However it allows you to minimise drag. WW2 was the epitome of radiator design as turbine engines made this field pretty much redundant. But there are some gems to be found in this area. https://history.nasa.gov/SP-445/ch5-5.htm https://reports.aerade.cranfield.ac.uk/bitstream/handle/1826.2/1425/arc-rm-1683.pdf

The energy content of 97 litres of fuel ~= 850 kW/h even at 30% efficiency that about 255kW/h at the prop. And the bonus is that as you use fuel you get lighter. A nice BMS might be this one. https://www.ennoid.me/ It's open source so if you don't want to buy it you might be able to save yourself a few shekels by building it. It has individual temperature sensors and achieves balanced charging. It also is scalable using master/slave model with the main controller controlling a number of smaller pack based units.

The easiest way to make this lighter would be to go on a diet. You're pushing the boundaries of the technologies, it sounds interesting good luck with it. Does your BMS monitor cell termperature? If you get your estimated 2 hours with your setup how long would a charge take a between flights?

It doesn't really matter whether a current battery is structural or not, they're just heavy. Battery powered electric airplanes might be OK for short duration training flights or for people who want to tool around on the weekend flying circuits. They're less attractive as a form of A-B transport. Batteries are heavy and the rate of improvement hasn't changed much in the last decade, cheaper yes, lighter no. One possibility for a battery would be a something like a lithium-air battery however there are significant issues to overcome prior to this becoming a thing. These issues may prove to be insurmountable, just look at fusion, conceptually easy in practice very difficult. You might want to consider aluminium-air batteries however they're non rechargeable which mightn't fit with the attractive vision of just plugging the plane in for a few hours before flying off, and they're not cheap. Another option for aircraft might be to resurrect the liquid salt reactor concept but while this is technically feasible in large transport airplanes I can't see many people waving flags to have flying reactors especially when we can't even get them built as a replacement for coal reactors. As an aside the French have the greatest percentage of nuclear power, are a net electrical energy exporter, have some of the lowest greenhouse gas emissions in Europe and power which costs about half the cost of Germany. They've been demonstrating how to operating their reactors in a dispatchable manner even though they weren't designed for this role allowing them to dovetail nicely with solar and wind generation.

There's a nice picture on wikipedia of Carb formation https://en.wikipedia.org/wiki/Carburetor_icing There will be some pressure drop caused by long intakes but nothing compared the cooling caused by the venturi and part throttle configuration

I agree however there are a number of factors at play here. Some of which appear to be self interest where conflict of interest should be declared. At the very least there should be significant representation from aviation groups which should include. The PPL community The commercial industry The Gliding community I struggle to see why there are so many AV med representatives, it is a well understood science and all of the representatives should understand them well. Two representatives should be more than sufficient. Also the terms of reference should explicitly reference the international experience which should be the key driver for change. If there hasn't been an increase in accidents related to self certification of medicals then the existing process would appear to provide little value. It should be up to the committee to justify how any additional process would add value.

The members of the committee are: Dr Anthony McArthy Dr Jeremy Robertson Dr Sara Souter Dr Priti Bhatt (Didn't attend) Dr Ian Hosegood Peter Antonenko Matt Bouttell John Raby (Didn't attend) Will Stamatopoulos (Didn't attend) It is concerning that the current approach to the committee selection provides a degree of medical expertise with more that 50% representation, however there is not a similar representation by the flying community, the ATSB or people with the relevant mathematical skills to assess risk appropriately. For example even someone with a B Medical Mathematics would provide signficantly greater rigor to the process. One of the key outcomes of studies into air safety is that the types of conditions identified by the specialist Aviation medical community rarely contribute to incidents involving pilot incapacitation. It is conceivable that providing advice to pilots in relation to food choices prior to flight would provide a greater benefit that the current regulatory process.

The report doesn't bode particularly well for the minimal approach https://www.casa.gov.au/first-part-67-twg-report It might be worthwhile getting appropriate representation on this working group as it is currently made upon of members whole profession depends upon the current process.

Back to the matter at hand. I hope that everyone did respond to the survey, and they encouraged their acquaintances to do the same. Key messages are It is more important to watch what you eat rather than get a medical. (more incapacitation due to food) Reuse, don't recreate, don't replace an ineffective bureaucratic control with another ineffective bureaucratic control. There's an existing standard just use it. Redirect the funding to where accidents actually occur, focus on providing material to teach people how to measure fuel, how to not fly into clouds and how to retain control of their airplane. I'd also like to see the flight school system reformed so that qualified instructors can operate outside the artificial model of a school and provide flexible instruction as required. There are a lot of people who want to learn to fly however the opportunities and costs are often prohibitive. Policies and funding encouraging the creation of more airstrips and aerodromes in fire prone areas. We need operational areas established which enable a concerted early suppression of fires. While helicopters can provide limited suppression what is needed is a workhorse with a combination of range, speed and capacity at low cost. There is probably enough capacity in the recently retired brigade to man such an endevour, especially if additional training was provided.

Just remind you wife that it's polite to drive at the signposted speed. Driving slowly creates a traffic hazard and put's those around you at risk and depending upon the jurisdiction may actually land you in hot water. If you're annoying other motorists there's something fundamentally wrong with your technique which you should look into. I followed an elderly gent driving the other day doing about 50km/h in an 80 zone. After pausing at a roundabout he drove out in front of a couple of cars which honked at him and he just hunkered down behind the wheel. I worry about drivers like that going through a school zone. Rather than an age based driving test I'd prefer to see a voting system where other drivers could nominate a driver for a test. Collect a couple of votes and you get a mandatory test. Both fast and slow drivers could be nominated however only allow one or two votes per person per year to stop the haters. The gent the other day would have taken my vote for the year and I suspect that he'd be removed from the road pretty quickly. It's interesting as some people age they try to slow down to reduce perceived risks, this includes just walking around however what often happens is that your abilities evolve to match the constraints. What often changes is stride length, as people age they often significantly reduce their stride length which eventually makes them unstable on their feet as the lose the ability to take a large step to stop falling, so remember even if you're slowing down make sure that you take big steps ;-).

Yes it's age discrimination however that age discrimination comes with good reason. https://dit.sa.gov.au/__data/assets/pdf_file/0019/247330/Older_Road_Users_-_Road_Crash_Fact_Sheet.pdf Even though older drivers often aren't driving in a risky manner they have more accidents and they tend to involve fatalities. Put bluntly many older drivers are a bit shit and the figures back this up. Hence the test, any competent driver should be able to pass the test. I do think that the test should be free though.

Generally the evidence points to the whole medical assessment process providing minimal value from a safety perspective. This include both the commercial and private flight environments. There have been no RPT crashes relating to pilot incapacitation due to a physiological condition. To put this is context a significantly greater loss of life has occurred due to mental illness however the industry doesn't focus on this aspect of safety and relies on "self disclosure" as the primary means of diagnosis. The expense associated with controlling this perceived risk has been enormous over the life of the industry and there is demonstrable evidence that removal of the control makes no difference to outcomes. While engagement with stakeholders in many instances makes sense in this case there's zero value in the process. The only segment of the community which is impacted is the business which has built up around this folly.