4 ms·

It doesn't work like that because all of the factors don't scale at the same rate. I'm not an engineer, so unfortunately I can't elaborate with much detail for

It doesn't work like that because all of the factors don't scale at the same rate. I'm not an engineer, so unfortunately I can't elaborate with much detail for you, but the general concept is that factors like aerodynamic efficiency and power efficiency can't be scaled up and down independently in a rudimentary way.

Someone 14y ago
The simplest one probably is that lift and drag scale with wing area, while aircraft weight scales with its volume. That means that, if you do things at quarter scale, you have 1/64 or about 1.5% of the weight, but 1/16 or about 6% of lift. Consequently, almost everything flies at that scale. The model plane will also be extremely robust, as its landing gear can take 1/16 of the original one, but has to carry only 1/64th. All of these are, of course, only valid to a rough approximation; look up "scaling laws" if you want to learn more)
evilkillerwhale 14y ago
That's not true at all. Their claims about wind tunnels are also ludicrous. Take a peak at the Reynold's number wikipedia page sometime. That's EXACTLY how aerospace engineers do preliminary calculations: by scaling aerodynamic factors (which is completely viable with a nearly incompressible fluid like low speed air). The idea that it gets MORE efficient by having more cargo violates the energy equation. Literally. That concept was disproved (utterly) when the sound barrier was broken. I call shenanigans.
- Scramblejams 14y ago
  I haven't looked at their claims, but strictly speaking it isn't impossible that adding cargo increases efficiency. How? Well, if the cargo is added in a location that moves the aircraft's center of gravity closer to the aircraft's neutral point (the center of lift for the entire aircraft), then less trim force from the elevator will be necessary for level flight, resulting in reduced trim drag. I'm not saying that their claims are correct, just that added weight can potentially result in improved performance, depending on how much weight it is and where the weight is placed. Also, regarding scaling results to model aircraft, the subject is called "dynamic scaling," and it's actually a complex task to scale the various model parameters to get good results. Take a look here: http://adg.stanford.edu/aa208/dynamics/nondimen.html http://adg.stanford.edu/aa208/dynamics/nondimen.html, under section 2.3.4, for the punchline. Also, an interesting history of dynamically scaled models can be found here: http://www.nasa.gov/pdf/601262main_ModelingFlight-ebook.pdf http://www.nasa.gov/pdf/601262main_ModelingFlight-ebook.pdf

Someone 14y ago

The simplest one probably is that lift and drag scale with wing area, while aircraft weight scales with its volume. That means that, if you do things at quarter scale, you have 1/64 or about 1.5% of the weight, but 1/16 or about 6% of lift. Consequently, almost everything flies at that scale. The model plane will also be extremely robust, as its landing gear can take 1/16 of the original one, but has to carry only 1/64th. All of these are, of course, only valid to a rough approximation; look up "scaling laws" if you want to learn more)

evilkillerwhale 14y ago

That's not true at all. Their claims about wind tunnels are also ludicrous. Take a peak at the Reynold's number wikipedia page sometime. That's EXACTLY how aerospace engineers do preliminary calculations: by scaling aerodynamic factors (which is completely viable with a nearly incompressible fluid like low speed air). The idea that it gets MORE efficient by having more cargo violates the energy equation. Literally. That concept was disproved (utterly) when the sound barrier was broken. I call shenanigans.

Scramblejams 14y ago
I haven't looked at their claims, but strictly speaking it isn't impossible that adding cargo increases efficiency. How? Well, if the cargo is added in a location that moves the aircraft's center of gravity closer to the aircraft's neutral point (the center of lift for the entire aircraft), then less trim force from the elevator will be necessary for level flight, resulting in reduced trim drag. I'm not saying that their claims are correct, just that added weight can potentially result in improved performance, depending on how much weight it is and where the weight is placed. Also, regarding scaling results to model aircraft, the subject is called "dynamic scaling," and it's actually a complex task to scale the various model parameters to get good results. Take a look here: http://adg.stanford.edu/aa208/dynamics/nondimen.html http://adg.stanford.edu/aa208/dynamics/nondimen.html, under section 2.3.4, for the punchline. Also, an interesting history of dynamically scaled models can be found here: http://www.nasa.gov/pdf/601262main_ModelingFlight-ebook.pdf http://www.nasa.gov/pdf/601262main_ModelingFlight-ebook.pdf