3 ms·

I am fascinated by the wings, you can see that they have been heavily optimised and wonder how much compute time went into perfecting them. I'd love to see a do

I am fascinated by the wings, you can see that they have been heavily optimised and wonder how much compute time went into perfecting them. I'd love to see a documentary on the design & construction. I have a carbon-fibre road bike and it is incredible how much they can tune the materal. Where it is rigid and where/ even how it flexes to dampen vibrations. Interestingly, most of that article is about the 737 Max issues (the MCAS software is a disaster, it's a push to even call it engineering).

bfieidhbrjr 7y ago
Recently I've been doing a teeny tiny bit of CFD again. You might be amazed at how little CFD goes in to wings. It's still a huge amount, but tunnel testing still wins. I was kind of surprised. As best I can tell, CFD is still kind of like impedance-based home body fat scales. They're kind of directionally accurate but have a pretty high error. I thought CFD would be a solved thing by now, but then I remembered how good (e.g. bad) weather prediction still is.
- LeifCarrotson 7y ago
  You might be interested in this bet on the LongNow site: http://longbets.org/753/ http://longbets.org/753/ Some people think that wind tunnels will be obsoleted by computational fluid dynamics within the decade. Others think that the problems with CFD are not a lack of compute power but a lack of comprehensive understanding and modeling of the physics at play, and expect that wind tunnels will be with us for quite a while. (Personally, I believe in the progress of technology and expect an eventual if not near-term breakthrough in CFD software will eventually obsolete the wind tunnel, but I also think that institutional inertia will keep a lot of wind tunnels and businesses that purchase time in them in operation for a decade or more after CFD's big breakthrough...)
  - Gravityloss 7y ago
    There are sources of error in wind tunnel testing too.
- pimlottc 7y ago
  For those who don’t know (like me), CFD stands for “computational fluid dynamics”. https://en.m.wikipedia.org/wiki/Computational_fluid_dynamics https://en.m.wikipedia.org/wiki/Computational_fluid_dynamics
- mhh__ 7y ago
  F1 teams spend a lot of time in wind tunnels looking for correlation between CFD and Reality. If there isn't any then the year is almost lost, usually.
pbourke 7y ago
> I'd love to see a documentary on the design & construction “21st Century Jet” is a documentary about the building of the 777. Looks like it’s available on YouTube.
deleted 7y ago
[deleted]
enginoor 7y ago
Construction is highly automated. Wing skins are created with automated fiber placement (AFP) https://www.seattletimes.com/business/boeing-aerospace/massive-speedy-robots-ready-to-build-composite-wings-for-boeing-777x/ https://www.seattletimes.com/business/boeing-aerospace/massi... The wings are assembled horizontally similar to the to A350. https://www.youtube.com/watch?v=yYXiz7GX4FI https://www.youtube.com/watch?v=yYXiz7GX4FI

bfieidhbrjr 7y ago

Recently I've been doing a teeny tiny bit of CFD again. You might be amazed at how little CFD goes in to wings. It's still a huge amount, but tunnel testing still wins. I was kind of surprised. As best I can tell, CFD is still kind of like impedance-based home body fat scales. They're kind of directionally accurate but have a pretty high error. I thought CFD would be a solved thing by now, but then I remembered how good (e.g. bad) weather prediction still is.

LeifCarrotson 7y ago
You might be interested in this bet on the LongNow site: http://longbets.org/753/ http://longbets.org/753/ Some people think that wind tunnels will be obsoleted by computational fluid dynamics within the decade. Others think that the problems with CFD are not a lack of compute power but a lack of comprehensive understanding and modeling of the physics at play, and expect that wind tunnels will be with us for quite a while. (Personally, I believe in the progress of technology and expect an eventual if not near-term breakthrough in CFD software will eventually obsolete the wind tunnel, but I also think that institutional inertia will keep a lot of wind tunnels and businesses that purchase time in them in operation for a decade or more after CFD's big breakthrough...)
- Gravityloss 7y ago
  There are sources of error in wind tunnel testing too.
pimlottc 7y ago
For those who don’t know (like me), CFD stands for “computational fluid dynamics”. https://en.m.wikipedia.org/wiki/Computational_fluid_dynamics https://en.m.wikipedia.org/wiki/Computational_fluid_dynamics
mhh__ 7y ago
F1 teams spend a lot of time in wind tunnels looking for correlation between CFD and Reality. If there isn't any then the year is almost lost, usually.

pbourke 7y ago

> I'd love to see a documentary on the design & construction “21st Century Jet” is a documentary about the building of the 777. Looks like it’s available on YouTube.

deleted 7y ago

[deleted]

enginoor 7y ago

Construction is highly automated. Wing skins are created with automated fiber placement (AFP) https://www.seattletimes.com/business/boeing-aerospace/massive-speedy-robots-ready-to-build-composite-wings-for-boeing-777x/ https://www.seattletimes.com/business/boeing-aerospace/massi... The wings are assembled horizontally similar to the to A350. https://www.youtube.com/watch?v=yYXiz7GX4FI https://www.youtube.com/watch?v=yYXiz7GX4FI