keta From Germany, joined Mar 2005, 440 posts, RR: 0 Reply 1, posted (3 years 3 months 2 weeks 21 hours ago) and read 1279 times:
Very very rough estimate: let's guess that the mean density is about 2600 kg/m3, corresponding to Al-Li alloy, which makes up quite a bit of the total weight on a modern aircraft. Other components have greater density (steel...), but others have less... With an empty weight of about 150000 kg (including engines), the volume would be 58 m3.
That was for some quick numbers. I have no idea what the mean density is, looking at the percent in weight of each material we could be closer, and I believe that information should be easily available. Maybe I'll give it a try later