4 ms·

I think that an engine+battery that is both powerful enough to power the wings, and lightweight enough to be able to take off, is the real challenge.

brippalcharrid 5y ago
You simply await the development of nuclear isotope batteries (up to a five-order-of-magnitude improvement on chemical batteries) as a mature technology: https://apps.dtic.mil/dtic/tr/fulltext/u2/a433348.pdf https://apps.dtic.mil/dtic/tr/fulltext/u2/a433348.pdf (And hope that the technology doesn't lead to a new era of arms proliferation with the use of non-fission primaries)
- perilunar 5y ago
  No need — regular hydrocarbons have a high enough specific energy to do the job. The largest pterosaur, Quetzalcoatlus, had a wingspan of ~10 meters and an estimated mass of 200–250kg [1]. I don’t know how much power they could produce, but it can’t have been more than a few horsepower given they weighed less than a half a horse. A 30cc petrol motor will easily output 2–3 horsepower, and weighs less than 10 kg. Combine it with wings from a hang glider (similar wingspan, weight ~30kg), and as long as the powertrain isn’t too heavy (compressor + pneumatic artificial muscles?), it seems possible to build something light enough to carry a human. 1. https://en.wikipedia.org/wiki/Quetzalcoatlus https://en.wikipedia.org/wiki/Quetzalcoatlus
  - brippalcharrid 5y ago
    Yep, there was I under the impression that this was more of a marginal endeavour than it really is; I was probably thinking along the lines of human-powered aircraft. I'd imagine that a lot of safety problems and requirements for a very skilled pilot could be reduced in the future with computer control/brain-computer interfaces and exoskeletons.
- smaddox 5y ago
  What are the odds that this went classified and is already working and being used in the field?

4 ms·

I think that an engine+battery that is both powerful enough to power the wings, and lightweight enough to be able to take off, is the real challenge.

by paulluuk 5y ago

brippalcharrid 5y ago
You simply await the development of nuclear isotope batteries (up to a five-order-of-magnitude improvement on chemical batteries) as a mature technology: https://apps.dtic.mil/dtic/tr/fulltext/u2/a433348.pdf https://apps.dtic.mil/dtic/tr/fulltext/u2/a433348.pdf (And hope that the technology doesn't lead to a new era of arms proliferation with the use of non-fission primaries)
- perilunar 5y ago
  No need — regular hydrocarbons have a high enough specific energy to do the job. The largest pterosaur, Quetzalcoatlus, had a wingspan of ~10 meters and an estimated mass of 200–250kg [1]. I don’t know how much power they could produce, but it can’t have been more than a few horsepower given they weighed less than a half a horse. A 30cc petrol motor will easily output 2–3 horsepower, and weighs less than 10 kg. Combine it with wings from a hang glider (similar wingspan, weight ~30kg), and as long as the powertrain isn’t too heavy (compressor + pneumatic artificial muscles?), it seems possible to build something light enough to carry a human. 1. https://en.wikipedia.org/wiki/Quetzalcoatlus https://en.wikipedia.org/wiki/Quetzalcoatlus
  - brippalcharrid 5y ago
    Yep, there was I under the impression that this was more of a marginal endeavour than it really is; I was probably thinking along the lines of human-powered aircraft. I'd imagine that a lot of safety problems and requirements for a very skilled pilot could be reduced in the future with computer control/brain-computer interfaces and exoskeletons.
- smaddox 5y ago
  What are the odds that this went classified and is already working and being used in the field?