Divalent

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  1. Just to be clear, I'm assuming the 100% total maximum power the aircraft can produce consists of 80% from the combustion engine, and 20% from the electric. I'm also assuming that cruising power needed will be 75% of that total maximum power, and in the example above, the batteries are sufficient to provide 5 minutes of sustained "reserve" capacity. These #s are variables you can adjust to fit reality for a particular aircraft and situation. Regardless of the numbers, as long as the combustion engine power exceeds what is needed to cruise by some amount, there will be excess power to recharge the batteries and restore reserve power during the cruise portion of the flight (and the descent portion as well). So the combustion engine will be running much closer to WOT than it would be if it was the only engine.
  2. "80%" is WOT for that combustion engine. (80% of the total max power, with the other 20% coming from the electric engine). So cruising at 75% of total power (combustion plus electric) for an engine where WOT can contribute only 80% means that engine would be at 75/80 = ~94% of WOT. So in this scenario, you'd always have an available 5% of max power as a reserve, plus whatever the status of the batteries are, up to 20% (maybe none very early in flight; full 20% but for only a short burst until batteries are replenished thereafter).
  3. The idea is that with the engine inside the hull, the exhaust can be treated before exiting. (Something that can't be done now with the engine out of the wing, as that exhaust it the thing that is giving the airliner the thrust.) See a link I posted a page or two back on the concept. (https://www.dropzone.com/forums/topic/266444-electric-aircraft-the-thread/?do=findComment&comment=4936934)
  4. I think you are strawmanning what is being proposed. The proposal is that an engine that provides less than the needed power to take off (say, 80%) is combined with an electric with batteries that can provide the needed 20% additional for takeoff climb. Then when cruising, where you need (say) 75% power, the remaining 5% of combustion power charges the batteries. So you don't need a 100% combustion engine to take off and charge. ~20 minutes of charging while cruising would then recover the initial battery power, which then gives you your reserve. Further, when the flight is descending and using only a fraction of the combustion engine output, you could charge the batteries even faster (meaning you might not need less than 5% excess capacity to charge your reserve). Yes, the economics will depend on whether the actual combination of weights and power make sense. But the scheme can't be dismissed on a logical basis by assuming you absolutely need a 100% combustion engine at some point in the flight, as that is not what is being proposed.
  5. Couldn't they recharge the batteries in flight? Maybe design for cruising at a tad less than 100% WOT, with the remaining % available to run a generator. Then you'd be able to call on that reserve later in the flight.
  6. Well, I think there is a bit of "chicken or egg" here: a dead looking forum doesn't encourage users, and no users reinforces the image that the forum is dead. There actually is some activity in the canopy forum, but you don't see it immediately as the ancient top pinned posts are cluttering up the initial view.
  7. An interesting variant is hybrid electric planes, even the size of big airliners. The idea is to have fuel burning engines inside the plane, which generate electricity to drive the electric motors. The benefit is that the exhaust can be passed through a pollution control system before exiting the plane, greatly reducing (90%+) nitrogen oxide emissions, which are apparently are a major source of harmful pollutants from airliners. But it's not a CO2 saver (would somewhat increase CO2 due to additional weight). https://scitechdaily.com/hybrid-electric-plane-concept-may-reduce-aviations-air-pollution-problem/ Another hybrid variant I ran across for smaller planes would include some batteries to provide additional power for takeoff. It's utility would depend on whether the weight saving of a smaller generator motor would offset the additional static weight of the batteries.
  8. Also important IMO is that many of the topical forums look like fossils from the past, no longer being actively curated. Just look at the "Pinned" threads in almost all of them. This place just screams "no one here but us rats". For example, in the Canopy forum, one of the pinned threads is the 2014(!) Canopy Pilot event list. I mean, someone new browsing that forum would instantly conclude it was a dead forum, abandoned by anyone serious.
  9. Another article that gives more specific details on the Ampaire hybrid version of the Cessna Skymaster (named the Electric EEL), which has two engines in a front-and-back orientation (push-pull). The front engine has been replaced with an electric, so it is configured with a 300 hp piston in the back, and a ~200 hp electric in front. Mokulele Airlines is current doing a month long series of trial flights on a 20 min route between two airports on Maui. Apparently it does the whole round trip (40 min) set on just one electric charge. Should provide good data on reliability and performance under simulated real route use. https://www.flyingmag.com/story/aircraft/ampaire-hybrid-electric-trials-begin/ Here's the Wikipedia page for the Electric EEL: https://en.wikipedia.org/wiki/Ampaire_Electric_EEL
  10. So I ran across this interesting article about the electric aviation industry. More of a survey of the companies and products that are underdevelopment, but not a lot about the technical details. Still ... https://qz.com/1943592/electric-airplanes-are-getting-close-to-a-commercial-breakthrough
  11. Bill worked in a pickle factory. He had been employed there for a number of years when he came home one day to confess to his wife that he had a terrible compulsion. He had an urge to stick his penis into the pickle slicer. His wife suggested that he should see a sex therapist to talk about it, but Bill indicated that he'd be too embarrassed. He vowed to overcome the compulsion on his own. One day a few weeks later, Bill came home absolutely ashen. His wife could see at once that something was seriously wrong. "What's wrong, Bill?" she asked. "Do you remember that I told you how I had this tremendous urge to put my… umm… member into the pickle slicer?" "Oh, Bill, you didn't." "Yes, I did." "My God, Bill, what happened?" "I got fired." "No, Bill. I mean, what happened with the pickle slicer?" "Oh - she got fired too."
  12. I dunno, "Washington" doesn't seem very politically-incorrect to me, even tho he was a white guy. But if they want to change, how about the "District Redskins"?
  13. Did you hear about the cannibal that passed his brother in the forest?
  14. Divalent

    covid-19

    Sorry, looks like I Triple(!) posted this
  15. Divalent

    covid-19

    To put this in perspective, assuming your flu numbers are correct, 490,000 hospitalizations over the duration of a flu season is a pretty low load for a country that has 160,000 ventilators. It's also about 1% of all that got the flu. So even if all 2018-19 flu hospitalizations required an ICU bed, when spread over 4-6 months it would not have come close to overwhelming the system. From the Diamond Princess cohort, ~50% of the 700 Covid-19 positives had symptoms, and IIRC, 30% required hospitalization, and half of them (15% of 700) needed an ICU bed with ventilator. But if 15% of just 35 M get Covid, (about 10% of US population), we're talking about 5 million needing an ICU at some point. (And is it reasonable to think we can limit this to just 10% of the population?) It would appear that we could only tolerate about 1 million or so people being infected at any one time to fill our existing ventilator capacity, unless we ramp up ICU beds and ventilators. (And what to do with non-Covid folks that would normally be occupying those beds? Estimates are that only 30% of them are available on average at any one time under normal circumstances.) Italy reached the breaking point with official counts in the tens of thousands. Yes, case counts are way below reality due to testing constraints, but our trajectory is about 10 days behind Italy, and based on per capita ventilator numbers, maybe we have another 6-10 days before the US would have hit the breaking point had we waited as long as Italy did to react. A lot is unknown and/or unclear, but hopefully the time we are buying will allow additional tools to come into play. If nothing else, time produce more masks and hazmat suits so at least we keep our existing medical folks from getting taken out of action (permanently or for recovery) and acquire more ventilators, test kits, and increased hospital space so we can handle a higher load. And more time to discover better treatments.