4 ms·

longer wings are more efficient but generate drag, which makes them an enemy of any high cruise speed.

GuB-42 5y ago
You are absolutely right. However the proposed plane has 3 wings, which, naively, would have the same drag as a wing 3 times longer. Non-naively, it goes beyond my knowledge of aerodynamics, but it is worth noting that multi-wing designs were very popular pre-WW2 but they are almost never seen today, which suggests a design compromise made obsolete by modern technologies.
- rsj_hn 5y ago
  Multiple wings were popular in the WW1 era and right up to WW2 because the engines were weak, meaning the plane flew slowly and thus needed a large surface area to generate lift. Lift ~ surface area of wing * velocity^2 https://www.grc.nasa.gov/www/k-12/airplane/lifteq.html https://www.grc.nasa.gov/www/k-12/airplane/lifteq.html At slow speeds, you need a lot of surface area. As speed increases, the required surface area decreases rapidly. Remember the first flight was made on what is basically the power of a modern lawnmower and so was quite slow and required massive wings which created all sorts of stiffness problems. The wings could tear off the plane in a sharp turn or even a gust of wind. Imagine a plywood skeleton covered in canvas held together by suspension wires. https://en.wikipedia.org/wiki/Bl%C3%A9riot_XI https://en.wikipedia.org/wiki/Bl%C3%A9riot_XI Thus the idea of cutting the wings in half and stacking them atop each other as biplanes or even triplanes in order to make them stiffer while maintaining a high surface area to generate the required lift at the slow speeds of the day. The stiffer wings also allowed for sharper turns, but suffered from more drag. But at those slow speeds, drag was not so much of an issue as it also goes with the square of velocity. That meant that biplanes had a big advantage in terms of maneuverability and stability and so outperformed the fragile, slow turning monoplanes in WW1 dogfights. But over time, improvements in engine technology allowed for much higher horsepower -- we went from 40hp engines to 1000hp engines in two decades. That increase in power allowed for increased speeds and reduced the need for wing surface area, and with the increased speed, drag became more of a concern, at which point biplanes were at a disadvantage. But during that transition period in the 20s and 30s, when early monoplanes were introduced and competed with biplanes they would still tend to stall and were not nearly as maneuverable. New materials -- corrugated iron -- were introduced to help stiffen the wings but even then the pilots of the era hated flying these "iron planes" compared to the more nimble wooden biplanes. WW2, of course, changed everything with monster engines and shockingly fast planes, leaving biplanes for the world of hobby flight and acrobatic exhibitions.

You are absolutely right. However the proposed plane has 3 wings, which, naively, would have the same drag as a wing 3 times longer. Non-naively, it goes beyond my knowledge of aerodynamics, but it is worth noting that multi-wing designs were very popular pre-WW2 but they are almost never seen today, which suggests a design compromise made obsolete by modern technologies.

rsj_hn 5y ago
Multiple wings were popular in the WW1 era and right up to WW2 because the engines were weak, meaning the plane flew slowly and thus needed a large surface area to generate lift. Lift ~ surface area of wing * velocity^2 https://www.grc.nasa.gov/www/k-12/airplane/lifteq.html https://www.grc.nasa.gov/www/k-12/airplane/lifteq.html At slow speeds, you need a lot of surface area. As speed increases, the required surface area decreases rapidly. Remember the first flight was made on what is basically the power of a modern lawnmower and so was quite slow and required massive wings which created all sorts of stiffness problems. The wings could tear off the plane in a sharp turn or even a gust of wind. Imagine a plywood skeleton covered in canvas held together by suspension wires. https://en.wikipedia.org/wiki/Bl%C3%A9riot_XI https://en.wikipedia.org/wiki/Bl%C3%A9riot_XI Thus the idea of cutting the wings in half and stacking them atop each other as biplanes or even triplanes in order to make them stiffer while maintaining a high surface area to generate the required lift at the slow speeds of the day. The stiffer wings also allowed for sharper turns, but suffered from more drag. But at those slow speeds, drag was not so much of an issue as it also goes with the square of velocity. That meant that biplanes had a big advantage in terms of maneuverability and stability and so outperformed the fragile, slow turning monoplanes in WW1 dogfights. But over time, improvements in engine technology allowed for much higher horsepower -- we went from 40hp engines to 1000hp engines in two decades. That increase in power allowed for increased speeds and reduced the need for wing surface area, and with the increased speed, drag became more of a concern, at which point biplanes were at a disadvantage. But during that transition period in the 20s and 30s, when early monoplanes were introduced and competed with biplanes they would still tend to stall and were not nearly as maneuverable. New materials -- corrugated iron -- were introduced to help stiffen the wings but even then the pilots of the era hated flying these "iron planes" compared to the more nimble wooden biplanes. WW2, of course, changed everything with monster engines and shockingly fast planes, leaving biplanes for the world of hobby flight and acrobatic exhibitions.