Ian

Hi All, Given variations in wind speed at altitude the "shortest" path between two points is may not be a direct route especially on longer flights. Does anyone know of software or other tools so optimise flight paths, engine time and fuel use?

Not sure if it's been mentioned however one of the key benefits of wired or pinned crown nuts is that they can be verified as "locked". Far more difficult with locktite or similar.

Yes, From the diagram (which may or may not be accurate), the rear of the wing is attaching to the fuselage in a section which is reducing. ie both sides are converging towards the tail. To reduce drag the section should be attempting to remain straight. The sections for the pictured wing root appears to be trying to achieve this straight line effect but its a bit hard to actually assess.

Looking at the Sonex shaped in the image below, the base of the wing might be making a high drag expanding "nozzle" mentioned in the video. To reduce the drag flattening this section until the end of the wing might help. A somewhat quick and dirty approach using something like CNC machined foam or 3D printed parts might be a lower labour approach. Using something like freecad could facilitate this approach. Another quick and dirty would be model some foam and cover it with duct tape.

If you're going down this path you probably want advice from someone who's already devoted a good chunk of their life to minimising drag. Around the 37 minute mark is where he gets into shapes to minimise drag. I think that fact that he managed to exceed 200mph with less than 65hp is a pretty good reference.

The current state of medicals in Australia is a bit of a farce. It is arbitrary, lacking a risk based approach and only serves to prop up the field of "Aviation medicine". https://www.casa.gov.au/basic-class-2-medical-certificate-fact-sheet-pilots Both ATSB and FAA have published papers on pilot incapacitation events over extended periods of time and it is both interesting and informative to understand the what, why and how these incidents occurred. However based upon these events it is unlikely that there is any differentiating factor where a DAME rather than a GP would have made a difference in any of the incidents. One of the biggest risk factors was food poisoning or flu or respiratory infections. Incapacitation events increase with age which is pretty much as you'd expect. Given that laser strike got such high ratings it should be considered against the backdrop of https://nbaa.org/aircraft-operations/safety/in-flight-safety/laser-strikes/aeromedical-effects-of-a-laser-strike/ and https://pubmed.ncbi.nlm.nih.gov/26651301/ From one article, "Significant injury resulting from a laser strike is unlikely." That's not to say that the morons doing this shouldn't be held accountable for being nuisances. However the key thing to keep in mind is, given the cost and relative ineffectual nature of this control, is whether these resources would be better spent elsewhere.

Is the turbulence associated with flying in the jetstream worthwhile given the fuel, time and airframe hours? I'm still waiting for someone to do some dynamic soaring near the jetstream as the delta V should be great enough to support it. The turbulence might be an issue though.

The article attached previously has a couple of "rules of thumb" which provide information on getting the most from your plane. Simply put it's angle of attack which largely dictates efficiency, going slow at low level or faster at altitude. Big wings and lightweight implies a higher optimal cruise ceiling. As you go higher the maximum power available to maintain the optimal angle of attack will be the limiting factor. This is what facthunter has been alluding to however hopefully he finds the article a good read. The other point is that you can push slightly faster without much of a fuel flow increase and hence a less full blader. Again as facthunter stated in the real world headwinds/tailwinds impact this however there's also a rule of thumb for calculating optimal speeds.

Yes I understand physics, however I was simple responding to the comment that Which wasn't quite correct, yes you'll have less power however some piston naturally aspirated planes have high ceilings and do get up there.

Headwinds and tailwinds are a factor however that's a bit of a red herring. By being able to use altitude you can fly high to get/avoid a tailwind/headwind. I'm not saying always fly high, however having more options provides advantages. Pistons get just as much of an advantage in trip time as a jet (up to a point), aerodynamics and physics don't change. However the limitations are Vne so the airframe designer simply hasn't made the airframe safe at speed and you also start running into the limitations of propellers and compressibility drag. You can keep stacking on compressors or use higher compression pistons to compensate. The key point is that a given airframe + load will use a set minimum amount of fuel per NM and this is dependant upon the minimum L/D. By going high you can reduce your trip time using the same amount of fuel. The attached article provides more concisely argued stance. To reduce your fuel consumption below this point requires you to change the physics of your plane. Ground effect is one way to do this and this was used by WW2 pilots getting home with low fuel. ps Jets are a bit different because turbines can't throttle like piston engines, their efficiency falls off a cliff. So they need to run near full power and hence they need to fly as high as they can to maintain the best angle of attack. Piston Airplane Cruise Performance.pdf

I agree that it might be a little monotonous, however the image posted earlier is a NA plane climbing to 17500 pretty easily and if you're going from point A to B you might be willing to accept the monotony. The longez service ceiling is 27000 feet which is also a naturally aspirated plane https://en.wikipedia.org/wiki/Rutan_Long-EZ Cabin heat or being impervious to the cold might be a good idea. Zooming along at low levels is a lot of fun however there are risks associated with not having altitude. Altitude also gives you more options especially if you're flying over unforgiving terrain, your options increase at the square of your altitude, Low = Increased risk.

One think that people don't appear to understand well is how altitude impacts efficiency. You will burn the same amount of fuel regardless of your altitude if you are flying at your best L/D ratio ie best glide ratio. Your most efficient flying speed is your best glide speed which is generally a bit slow so people fly much faster and burn lots more fuel. This best glide speed is your optimal angle of attack at which drag is lowest. However you best glide speed increases as your altitude increases, effectively your drag remains constant so the higher you go the shorter your trip time. However your fuel burn remains constant (ignoring climb and descent phases) Energy = Force X Distance (drag is constant and Distance is constant so energy remains the same) There are a couple of flies in the ointment through, engines lose power as altitude increases limiting your maximum altitude and secondly your flutter speed Vne remains at altitude even though the air is thinner. The other fly in the ointment is where to buy oxygen at a price at low cost. Unfortunately there doesn't appear to be many options.

There's no requirement for IFR, IFR is required for class A airspace which is Above FL245 outside radar coverage Above FL180 within radar coverage So the opportunity to expand your horizons is simply limited by oxygen and your aircraft. The chart below is an example of a really good resource provided to the flying community. https://www.casa.gov.au/australian-airspace-structure

The graph shows a defiant which is NA and while the rate of climb is slowing it remain adequate up to FL180. Agree completely on the risks associated with icing, weather and the lack of effective mitigations on GA aircraft. It's somewhat ironic that on planes where rejecting heat is often an issue that the cold is a problem in other areas.

There's a few reasons. Oxygen improves awareness even at lower altitude, fly to 10000 feet and take a few maths questions, you'll be surprised at how slow you become. Speed, efficiency and angle of attack, your most efficient speed occurs at the optimal angle of attack so you can minimise flight time and fuel burn by going high. weather, sometimes the weather is just bad on the way and good at either end. A bit of altitude might be all you need. Some people swear by the fact that oxygen makes them feel more refreshed even after a flight below 10000. Tailwinds.

Like many things it depends on the dose, oxygen toxicity results from inhaling oxygen as higher partial pressures, so inhaling higher concentrations of oxygen at altitude is a good thing if the partial pressure is equivalent to sea level oxygen. 100% oxygen at sea level not so good, even worse if you're diving. U2 pilots have been doing it for decades however their problems recently have related to the bends due to higher operational tempos. https://www.smithsonianmag.com/air-space-magazine/killer-at-70000-feet-117615369/ With the little blood oxygen sensors becoming readily available you can monitor your oxygen levels with little trouble. Even simple maths can become harder at altitude.

I was never sure how the non-aviation O2 concentrators coped with altitude, for example the "Inogen One At Home" system is rated to 8000 feet". Even with an oxysaver cannula you need about 1.6L/m to maintain blood oxygen. https://www.peter2000.co.uk/aviation/oxygen2/index.html If someone want to buy and test them that would be good 🙂

I was wondering what the best valve types and cylinder sizes for oxygen were. And is getting refills for your own cylinders available in Australia or more specifically Canberra or Sydney. The market appears to be dominated by companies only doing refills on their own cylinders. The US market cylinders have CGA-540 male fittings and the Australian market has CGA-540 female fittings. If I bought pin indexed CGA-870 valved cylinders am I going to be able to get them filled with industrial/veterinarian oxygen? There's an interesting article on the supply of oxygen here https://www.avweb.com/features/pelicans-perch-13getting-high-on-welders-oxygen/ Not sure that it's true but it's food for thought. I've always thought that the options that oxygen provides would be beneficial There are a few more articles on oxygen here https://www.kitplanes.com/homebuilt-o2/ https://www.kitplanes.com/military-oxygen/ https://www.kitplanes.com/how-to-use-your-oxygen-system/

I liked the quote that the the head of Coke made about some of the conspiracy theories about the introduction of new coke" ""We're not that dumb, and we're not that smart."

I spoke to a pilot the other day who fervently believed in existence of chemtrails and other Government/UN conspiracies to install overlords or something similar. I was a bit surprised because as a pilot he'd have an understanding of the types of infrastructure required to perform such as feat, just the the logistics alone would be incredibly difficult. As well as this being a pilot he should have a basic understanding of the weather and be able to extrapolate why some contrails will last significantly longer periods than others. The thing that really gets me is that everyone knows that Government in general has a degree of incompetence large enough to make them the butt of many jokes, so how does this seemingly incompetent organisation run this massive secret operation hidden from the eyes of the major news organisations and only facebook or whereever they get information from etc. We all deal with CASA and know what stellar performers they are like. We also saw the head of BOM trying to rebrand the organisation in the middle of a major flood so we know that they're not savants. Governments in general are prone to hubris, overreach and mismanagement, they're made up of average people by design, because we want the best and brightest people to be running business and research organisations. Wikipedia maintains a list of conspiracy theories https://en.wikipedia.org/wiki/List_of_conspiracy_theories Are views like this common in the flying community or are they the exception to the rule, I had thought that pilots, given the fact that remaining airbourne requires practitioners to be able to use critical thinking, would be less likely to side with the conspiracy theorists.

What I was alluding to is that the likelihood of losing all engines in a single birdstrike incident is far less likely. Unlike volcanic ash which is more of an environmental issue. There was a shortage of air freight capacity during the pandemic. My understanding was that freight was generally a secondary load type after passengers, less passengars = less freight.

The simplest way to stop inequality is to get rid of inherited wealth. Nothing is less capitalistic than inherited wealth as it involves gifting money to people based upon an accident of birth rather than the accumulation of capital based on ability. I suspect that there would be many more programs aimed towards innovation and wealth creation if this were the case rather than programs designed to enhance the status quo. That being said death taxes have always been unpopular. I have occasionally wondered if a 3 or 4 engined plane would have been forced to ditch given the same circumstances. https://en.wikipedia.org/wiki/US_Airways_Flight_1549

Does the Stratux provide an ADS-B out option? Having a system which doesn't provide an out is pretty limited especially if lots of people start using it.

On batteries only 250km. The 1000km is based upon some form of hydrogen cycle. I'm not sure what bits are reality and what bits are aspirational or whether the range is calculated with or without a payload. Hydrogen as a fuel is hard and "green" hydrogen is also also very hard. I might be wrong however I suspect that as an energy carrier it is mostly folly. Take the case of Hydrogen production, solar and wind are intermittent, so you need to cycle/throttle your generation process, the only electrolysers which can be throttled are PEM electrolysers. However PEM electrolysers require iridium which is part of the platinum group and it one of the rarest commercially produced elements. Current production is only 7 tons a year and it is a very scarce resource. To provide a terrawatt of hydrogen generation would require about 27 years of current iridium production and the world economy would requires about 4 TW of continual electrical production. This doesn't include non-electrical energy flows which hydrogen is meant to replace. You could use other types of electrolysers however they need to be kept running which doesn't work with intermittent sources. Hydrogen is a great fuel once you're in the air, it's weight per unit of energy is very good but production and logistics are difficult. Fossil fuel companies are hyping Hydrogen because they're the only possible suppliers from an economic perspective, but why not just use natural gas instead, it's cheap? Elon Musk chose that path for his rockets because H2 is hard and CH4 is easier and cheaper. https://aviationweek.com/air-transport/aircraft-propulsion/can-aviation-use-liquified-natural-gas-reduce-its-carbon But going down the Fossil fuel route still produces CO2 which is bad even though CH4 produces less.

Piranha solution will dissolve the deposits. However it will probably also continue to dissolve the entire piston 🙂 But it is good on glass.