3 ms·
I wonder if a RTG could produce enough to run an electric quad or optocopter? For certain applications if unmanned you wouldn’t really need to worry about shie
by sneak 2y ago
I wonder if a RTG could produce enough to run an electric quad or optocopter?
For certain applications if unmanned you wouldn’t really need to worry about shielding. I wonder how long those motors can run continuously?
- alejohausner 2y agoThe RTGs on the Voyager spacecraft weigh 38kg. They initially produced 160 Watts. That sounds like a no-go to me.
- FredPret 2y agoIt might not have great power density but boy does that thing keep going for decades
- jaggederest 2y agoFull power for ~10,000 years, give or take.
- fragmede 2y agoNo. You're thinking of nuclear waste. Voyager's RTG lasted "only" a few decades.
- jaggederest 2y agoDesign choice, not an inherent constraint. Plutonium has a half life in excess of 25000 years
- chickenbig 2y ago> Design choice Presumably this is why Pu-238 is used for RTGs where power density matters; a half life of 87.7 years means a reasonably long working life using with only 1/3% of the mass compared to Pu-239.
- jaggederest 2y agoOh yeah you're probably right, I didn't think about it being a different isotope. I figured they just kept it near-critical to keep it toasty instead of a shorter half life.
- mlindner 2y agoLong half life also means low energy output.
- Gibbon1 2y agoI think you need 1 hp per 10-15 lbs of weight to fly. I think that's around 130 W/kg. I checked a piper cub is something like 100. Other hand Pu-238 produces 570 W/kg. A piper cub with it's 48kw engine would need 87kg of Pu-238 to produce the same energy. I looked up the cost, $1968/g. So 48kw would cost $171 million. Interesting idea but doubt.
- Gibbon1 2y agoForgot the efficiency of an RTG is at most 10%. So you'd need 870kg of Pu-238. Which is twice what a Piper Cub weighs.
- brnt 2y agoI wish Toshiba would have actually sold that RTG laptop battery. Imagine never having to charge!
- hypercube33 2y agoNot just Voyager but the mars robots as well.
- beefman 2y agoDragonfly is NASA's RTG-powered octocopter. It launches for Titan in 2028 https://dragonfly.jhuapl.edu/ https://dragonfly.jhuapl.edu/ https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe) https://en.wikipedia.org/wiki/Dragonfly_(Titan_space_probe)
- doctor_eval 2y agoI got nerd sniped by this and asked GPT some questions. Given a 45kg RTG plus the weight of the drone itself, you’d need to be able to lift, say, 60kg. Energy required to hover 60kg using a 4-rotor drone at 70% efficiency is about 10kW - according to GPT. I don’t know enough to say if this is true or not. Assuming it’s correct, and that a 45kg RTG generates about 300 watts, give or take, the answer is: no.
- namibj 2y agoThere is no technical minimum; the only thing to keep in mind is that lift/drag ratio relates potential energy (moving mass up against gravity) to travel distance. This applies independent of speed and vehicle type (even running counts!).
- mr_toad 2y agoNuclear Stirling engines can run for a decade or more, but are still too heavy for a helicopter.