36 ms·

Prototype can hold 6 passengers. The design can scale up to 19, but "the low-drag laminar flow model relies on a width-to-length ratio that'd be impractical in

Prototype can hold 6 passengers. The design can scale up to 19, but "the low-drag laminar flow model relies on a width-to-length ratio that'd be impractical in a bigger bird" so it won't work for airline use.

jonplackett 4y ago
Was wondering about this - im just not that impressed about anyone making personal jets more efficient. Those things shouldn’t be in the sky in the first place.
- nawgz 4y ago
  Fully agreed. Personal aviation is ludicrously inefficient and still often remains outside of meaningful regulation in key ways like using leaded fuels. Poisoning the globe and locales for one person’s convenience should always be questioned as a sign of inequality too far gone
  - amscanne 4y ago
    I imagine that at capacity, they can just as efficient as larger jets (if not more efficient). There may be a sweet spot in terms of efficiency that can be achieved that is smaller than what we've got now. We've already seen jumbo jets fall out of favor, and e.g. this can be seen in the sales of the A380 and 787 (launched around the same big, with A380 going big, and 787 going efficient and mid-sized with about 10x the sales). I imagine that planes would get smaller still, but the reason they don't is that even with high oil prices, human costs still tend to dominate the cost of a flight (two pilots, cabin crew). It's not so hard to imagine that with more automation it will become viable to have much smaller, more frequent routes that are both more economically and environmentally efficient.
    - nawgz 4y ago
      Jetliners have an industry average 51mpg per passenger. Private learjets pull, at capacity, 28mpg per passenger. I’ll let you decide which one of these flies around more often at lower percentages of capacity.
      - nickff 4y ago
        Learjet was a brand name (used to be an independent company founded by Bill Lear), which is no longer active (after having been acquired and subsequently discontinued). The more generic terms are 'general aviation' and 'business aviation'; most small jets are 'business jets'.
        nawgz 4y ago
        I am citing specific statistics for a specific and popular private jet, as these things are not well analyzed for not surprising reasons. Feel free to prove the point with statistics, semantics are definitely an aside to the point at hand
        nickff 4y ago
        You're comparing obsolete small jets to a much newer fleet of commercial passenger aircraft. While business jets do tend to be older, your choice is rather extreme, and introduces a huge bias. This website has some interesting examples of more modern aircraft in a few categories: https://www.flyingmag.com/the-most-fuel-efficient-aircraft-in-several-categories/ https://www.flyingmag.com/the-most-fuel-efficient-aircraft-i...
        nawgz 4y ago
        A bunch of 4mpg 7-8 seaters align perfectly with my criticism of private jets. Actually, I don’t really understand what leads you to think there is any pressure in this space for fuel efficient development. In the space of jetliners, the airlines optimize for cost, of which fuel is a primary driver. While it is cool local planes pull 25mpg, they spew lead on their local communities. I don’t think humanity can put the cat of air travel back in the bag, and if I understand correctly the SUV market is actually driving as much CO2 emissions as the entirety of aviation; I still don’t see why individuals should be privileged to do such damage of poison and inefficiency for their pleasure. It is pleasing to others to imagine a long lived humanity on a globe hosting life as we know it, after all.
      - 4y ago
  - sokoloff 4y ago
    Jets [and turboprops] don’t use leaded fuel. Many of the small, piston-engined airplanes do, but because current FAA regulation forces them to, not because of a lack of regulation.
    - DakotaR 4y ago
      And some engines are rated to run automotive gas, but it's just not available at smaller airports.
      - sokoloff 4y ago
        Most of those are only rated to run on E0 (ethanol-free) gasoline, which is also hard to find outside the airport fence in most places.
        grogenaut 4y ago
        I was actually surprised when I looked how many places carry e0. There were several near me in Seattle. https://www.pure-gas.org/ https://www.pure-gas.org/
        noduerme 4y ago
        Off-topic question. Did you have to advance your ignition timing when you started running E0? I've thought about using it in my Datsun, especially with E15 rolling out now. I've got a 1980 280ZX, modded with flat top pistons mated w/ a p79 head for about 10:1 compression. Currently though, with normal E10 92 octane gas, I have the distributor set to maximum advance and even with that I feel like it's not getting peak performance. In theory I should already be running lower octane for more advance, but I don't b/c I worry about detonation, and my understanding is that E0 is also more prone to detonation than the same octane ethanol blend b/c it runs hotter without the evaporative cooling of the ethanol, so I might even need to back off the advance when really I'd like to increase it. Did you find running E0 retarded the timing and/or led to any performance changes?
  - S201 4y ago
    Let's not be so dramatic as to say that the general aviation fleet is single handedly responsible for poisoning the world with lead. When leaded car gas was still in use it resulted in 4-5 million tons of lead emissions per year.[1] The use of leaded aviation fuel contributes 500 tons per year according to the EPA[2]. Compared to 5,000,000 tons for cars historically. Of course, any lead is not good and we should be shooting for zero. Which is the goal of the unleaded G100UL aviation fuel. But let's not try to say that personal aviation is evil when it's contributing a fraction of a percent of lead contamination. Frankly, we have bigger pollution problems to worry about than a very small amount of lead emissions from an ever shrinking fleet of piston powered aircraft. Mind you that general aviation is more than rich people flying around in their planes. It's medical flights, it's training future airline pilots, it's aerial surveying, and many more critical tasks for society. 1. https://grist.org/regulation/leaded-gasoline-lead-poisoning-united-nations/ https://grist.org/regulation/leaded-gasoline-lead-poisoning-... 2. http://www.reidhillview.com/EPA_GA_Lead_2002.pdf http://www.reidhillview.com/EPA_GA_Lead_2002.pdf
    - nawgz 4y ago
      https://paloaltoonline.com/news/2021/08/06/new-study-finds-local-airports-are-raising-blood-lead-levels-in-children https://paloaltoonline.com/news/2021/08/06/new-study-finds-l... I in no way imply aviation is the greatest poison emitted by humanity; it is one of the most selfish emissions by any standard. It is not that leased fuels support meaningful industry as suggested, nor is it as if there are not alternatives. Instead, the FAA and pilots of piston driven planes have simply decided lead poisoning is a justifiable price to pay for people living near an airport in exchange for individuals getting to fly their quarter million+ $ aircraft. Everything you suggest it is useful for could be performed with the already proven and no longer new unleaded alternative. Defending this practice is asinine.
      - S201 4y ago
        The source you cited conveniently links to a 404 page for the study it cites. But yes, I've read quite a bit about the Reid-Hillview Airport saga. These claims of leaded gas hurting the children around airport is just the newest in a long list of excuses to close airports so their land can be redeveloped into more strip malls and condos. These neighborhood groups are biased towards wanting airports closed. It's textbook NIMBYism and they'll look for any excuse to achieve their goals. If it's not leaded gas, it's something else. > Instead, the FAA and pilots of piston driven planes have simply decided lead poisoning is a justifiable price to pay for people living near an airport in exchange for individuals getting to fly their quarter million+ $ aircraft. Don't buy a house near an airport if you're concerned about it then. The airport was there before the houses were. > Everything you suggest it is useful for could be performed with the already proven and no longer new unleaded alternative. Defending this practice is asinine. Where did I say I liked leaded gas exactly? I'm quite excited about G100UL being rolled out, even if it costs a bit more, so I can stop having this exact argument about how we need to close airports because of leaded gas. Everything with the FAA moves slowly, but it's moving. We're about to have unleaded gas for all planes. By the way, the average Cessna 172 is well under $100k (at least prior to the previous two years before asset prices for everything went through the roof). For every fancy late model Cirrus SR22T there's 10 more shitbox Cessna's from the 1970s barely hanging onto life. You think of private pilots as all extremely wealthy individuals. Most of us are solidly middle class. How many people have boats or RVs that cost the same or more? Small planes fall into that same category.
- Robotbeat 4y ago
  19 passengers isn’t personal aviation. It comparable to passenger aircraft used in places like islands and elsewhere where demand isn’t enough for big jets and there’s no ground option. Fundamentally, it could be nearly as cost efficient as large jets. The pilot wage is a small portion of the overall cost. A big reason big jets are big is because jet propulsion scales down poorly while electric scales down very well.
deleted 4y ago
[deleted]
simne 4y ago
For plane engineering aware person, all ok. - Commercial planes begin at about 50-60 seats, less are non-viable. Normal commercial size - 100 seats. For air-dynamics, 3 times capacity enlarge (from 6 to 18) typically possible, but more changes too much. And 3 times capacity in avia measured non linear, but with famous square-cube rule, which mean, change size will increase mass as square, but capacity as cube, so to got 3x capacity, need 1.443 increase of size (1.442^3=3.0046853).
rbanffy 4y ago
> "the low-drag laminar flow model relies on a width-to-length ratio that'd be impractical in a bigger bird" so it won't work for airline use. We can always reimagine airports as well.

jonplackett 4y ago

Was wondering about this - im just not that impressed about anyone making personal jets more efficient. Those things shouldn’t be in the sky in the first place.

nawgz 4y ago
Fully agreed. Personal aviation is ludicrously inefficient and still often remains outside of meaningful regulation in key ways like using leaded fuels. Poisoning the globe and locales for one person’s convenience should always be questioned as a sign of inequality too far gone
- amscanne 4y ago
  I imagine that at capacity, they can just as efficient as larger jets (if not more efficient). There may be a sweet spot in terms of efficiency that can be achieved that is smaller than what we've got now. We've already seen jumbo jets fall out of favor, and e.g. this can be seen in the sales of the A380 and 787 (launched around the same big, with A380 going big, and 787 going efficient and mid-sized with about 10x the sales). I imagine that planes would get smaller still, but the reason they don't is that even with high oil prices, human costs still tend to dominate the cost of a flight (two pilots, cabin crew). It's not so hard to imagine that with more automation it will become viable to have much smaller, more frequent routes that are both more economically and environmentally efficient.
  - nawgz 4y ago
    Jetliners have an industry average 51mpg per passenger. Private learjets pull, at capacity, 28mpg per passenger. I’ll let you decide which one of these flies around more often at lower percentages of capacity.
    - nickff 4y ago
      Learjet was a brand name (used to be an independent company founded by Bill Lear), which is no longer active (after having been acquired and subsequently discontinued). The more generic terms are 'general aviation' and 'business aviation'; most small jets are 'business jets'.
      - nawgz 4y ago
        I am citing specific statistics for a specific and popular private jet, as these things are not well analyzed for not surprising reasons. Feel free to prove the point with statistics, semantics are definitely an aside to the point at hand
        nickff 4y ago
        You're comparing obsolete small jets to a much newer fleet of commercial passenger aircraft. While business jets do tend to be older, your choice is rather extreme, and introduces a huge bias. This website has some interesting examples of more modern aircraft in a few categories: https://www.flyingmag.com/the-most-fuel-efficient-aircraft-in-several-categories/ https://www.flyingmag.com/the-most-fuel-efficient-aircraft-i...
        nawgz 4y ago
        A bunch of 4mpg 7-8 seaters align perfectly with my criticism of private jets. Actually, I don’t really understand what leads you to think there is any pressure in this space for fuel efficient development. In the space of jetliners, the airlines optimize for cost, of which fuel is a primary driver. While it is cool local planes pull 25mpg, they spew lead on their local communities. I don’t think humanity can put the cat of air travel back in the bag, and if I understand correctly the SUV market is actually driving as much CO2 emissions as the entirety of aviation; I still don’t see why individuals should be privileged to do such damage of poison and inefficiency for their pleasure. It is pleasing to others to imagine a long lived humanity on a globe hosting life as we know it, after all.
    - 4y ago
- sokoloff 4y ago
  Jets [and turboprops] don’t use leaded fuel. Many of the small, piston-engined airplanes do, but because current FAA regulation forces them to, not because of a lack of regulation.
  - DakotaR 4y ago
    And some engines are rated to run automotive gas, but it's just not available at smaller airports.
    - sokoloff 4y ago
      Most of those are only rated to run on E0 (ethanol-free) gasoline, which is also hard to find outside the airport fence in most places.
      - grogenaut 4y ago
        I was actually surprised when I looked how many places carry e0. There were several near me in Seattle. https://www.pure-gas.org/ https://www.pure-gas.org/
        noduerme 4y ago
        Off-topic question. Did you have to advance your ignition timing when you started running E0? I've thought about using it in my Datsun, especially with E15 rolling out now. I've got a 1980 280ZX, modded with flat top pistons mated w/ a p79 head for about 10:1 compression. Currently though, with normal E10 92 octane gas, I have the distributor set to maximum advance and even with that I feel like it's not getting peak performance. In theory I should already be running lower octane for more advance, but I don't b/c I worry about detonation, and my understanding is that E0 is also more prone to detonation than the same octane ethanol blend b/c it runs hotter without the evaporative cooling of the ethanol, so I might even need to back off the advance when really I'd like to increase it. Did you find running E0 retarded the timing and/or led to any performance changes?
- S201 4y ago
  Let's not be so dramatic as to say that the general aviation fleet is single handedly responsible for poisoning the world with lead. When leaded car gas was still in use it resulted in 4-5 million tons of lead emissions per year.[1] The use of leaded aviation fuel contributes 500 tons per year according to the EPA[2]. Compared to 5,000,000 tons for cars historically. Of course, any lead is not good and we should be shooting for zero. Which is the goal of the unleaded G100UL aviation fuel. But let's not try to say that personal aviation is evil when it's contributing a fraction of a percent of lead contamination. Frankly, we have bigger pollution problems to worry about than a very small amount of lead emissions from an ever shrinking fleet of piston powered aircraft. Mind you that general aviation is more than rich people flying around in their planes. It's medical flights, it's training future airline pilots, it's aerial surveying, and many more critical tasks for society. 1. https://grist.org/regulation/leaded-gasoline-lead-poisoning-united-nations/ https://grist.org/regulation/leaded-gasoline-lead-poisoning-... 2. http://www.reidhillview.com/EPA_GA_Lead_2002.pdf http://www.reidhillview.com/EPA_GA_Lead_2002.pdf
  - nawgz 4y ago
    https://paloaltoonline.com/news/2021/08/06/new-study-finds-local-airports-are-raising-blood-lead-levels-in-children https://paloaltoonline.com/news/2021/08/06/new-study-finds-l... I in no way imply aviation is the greatest poison emitted by humanity; it is one of the most selfish emissions by any standard. It is not that leased fuels support meaningful industry as suggested, nor is it as if there are not alternatives. Instead, the FAA and pilots of piston driven planes have simply decided lead poisoning is a justifiable price to pay for people living near an airport in exchange for individuals getting to fly their quarter million+ $ aircraft. Everything you suggest it is useful for could be performed with the already proven and no longer new unleaded alternative. Defending this practice is asinine.
    - S201 4y ago
      The source you cited conveniently links to a 404 page for the study it cites. But yes, I've read quite a bit about the Reid-Hillview Airport saga. These claims of leaded gas hurting the children around airport is just the newest in a long list of excuses to close airports so their land can be redeveloped into more strip malls and condos. These neighborhood groups are biased towards wanting airports closed. It's textbook NIMBYism and they'll look for any excuse to achieve their goals. If it's not leaded gas, it's something else. > Instead, the FAA and pilots of piston driven planes have simply decided lead poisoning is a justifiable price to pay for people living near an airport in exchange for individuals getting to fly their quarter million+ $ aircraft. Don't buy a house near an airport if you're concerned about it then. The airport was there before the houses were. > Everything you suggest it is useful for could be performed with the already proven and no longer new unleaded alternative. Defending this practice is asinine. Where did I say I liked leaded gas exactly? I'm quite excited about G100UL being rolled out, even if it costs a bit more, so I can stop having this exact argument about how we need to close airports because of leaded gas. Everything with the FAA moves slowly, but it's moving. We're about to have unleaded gas for all planes. By the way, the average Cessna 172 is well under $100k (at least prior to the previous two years before asset prices for everything went through the roof). For every fancy late model Cirrus SR22T there's 10 more shitbox Cessna's from the 1970s barely hanging onto life. You think of private pilots as all extremely wealthy individuals. Most of us are solidly middle class. How many people have boats or RVs that cost the same or more? Small planes fall into that same category.
Robotbeat 4y ago
19 passengers isn’t personal aviation. It comparable to passenger aircraft used in places like islands and elsewhere where demand isn’t enough for big jets and there’s no ground option. Fundamentally, it could be nearly as cost efficient as large jets. The pilot wage is a small portion of the overall cost. A big reason big jets are big is because jet propulsion scales down poorly while electric scales down very well.

deleted 4y ago

[deleted]

simne 4y ago

For plane engineering aware person, all ok. - Commercial planes begin at about 50-60 seats, less are non-viable. Normal commercial size - 100 seats. For air-dynamics, 3 times capacity enlarge (from 6 to 18) typically possible, but more changes too much. And 3 times capacity in avia measured non linear, but with famous square-cube rule, which mean, change size will increase mass as square, but capacity as cube, so to got 3x capacity, need 1.443 increase of size (1.442^3=3.0046853).

rbanffy 4y ago

> "the low-drag laminar flow model relies on a width-to-length ratio that'd be impractical in a bigger bird" so it won't work for airline use. We can always reimagine airports as well.