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Launch HN: Radical (YC W23) – Autonomous high-altitude solar aircraft

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Re: Launch HN: Radical (YC W23) – Autonomous high-altitude solar aircraft

#201

Post by acyou »

I tried a few back of the envelope calculations, with a 21700 cell with the same characteristics as a Boeing 737. Looks like you don't need that much power to stay aloft when you're small. If you're buoyant, even less. I guess small insects take great advantage of this.

If potential energy can be stored as height, why do you need batteries at all, or why would better batteries help? Can you get a low enough descent rate to glide all night and climb all day?

How much power is realistically required for night-time station-keeping?

I would have thought that large birds would be around the right size, shape, weight and flexibility for dealing with flight problems. Why would bigger be better in a highly scale-independent propulsion system ? Is it just the back of the envelope size needed for enough solar gain? Why is 110 ft needed? As others say, 110 ft sounds much too big to live through turbulence...

Re: Launch HN: Radical (YC W23) – Autonomous high-altitude solar aircraft

#202

Post by cashsterling »

This is very cool... I worked for a short-lived start-up in 2016 that was trying to do exactly this: solar-powered, electric high-altitude (60k feet) & long endurance drones for similar applications (connectivity, observation, and remote sensing). We were designing our-own carbon fiber air-frames and even bought (and mostly installed) a MTorres automated carbon fiber layup system.

I ran the material science group (I'm a ChemE) so the carbon fiber layup and manufacturing, solar panel materials and integration, battery system, avionics light-weighting and protection, etc. all fell under my domain. I'm not great in the carbon fiber department: we had a lot of help from a company who was our main investor.

As you know, the materials science challenges between flying a drone at 10k feet and below and flying HALE are extremely different... the day/night temperature oscillations on wing are huge, thermal management of the battery system (to heat it, keep it warm enough) is critically important, and so many more.

There are a lot of interesting problems to solve in this space. You've probably thought of most/all of them but I'd be happy to chat.

Re: Launch HN: Radical (YC W23) – Autonomous high-altitude solar aircraft

#204

Post by tgtweak »

Have you guys thought of borrowing a page from the in-flight tanker/jet refueling playbook and having hot-swappable battery packs that would enable multi-year in-situ sorties with a dedicated swap aircraft or would it just be cheaper to send a replacement vehicle up to rendezvous and take over when it's time to swap out?

I imagine that with the general improvements in high cycle-count rechargeable battery chemistry and power/weight density improvements the payloads and sortie lengths would get pretty attractive even in the 4-5 year technology horizon.

What is the commercial application for this? What is the economy vs LEO satellite constellations? What is the expected equipment payload and cost of the 110ft wingspan prototype?

Re: Launch HN: Radical (YC W23) – Autonomous high-altitude solar aircraft

#205

Post by cyrieln »

cashsterling wrote: post #202

This is very cool... I worked for a short-lived start-up in 2016 that was trying to do exactly this: solar-powered, electric high-altitude (60k feet) & long endurance drones for similar applications (connectivity, observation, and remote sensing). We were designing our-own carbon fiber air-frames and even bought (and mostly installed) a MTorres automated carbon fiber layup system. I ran the material science group (I'…

Thanks! Sounds like you have lots of relevant experience in this domain. Would love to chat. E-mail is in my bio.

Re: Launch HN: Radical (YC W23) – Autonomous high-altitude solar aircraft

#206

Post by inemesitaffia »

denton-scratch wrote: post #197
Aspos wrote: post #132

Earlier quoted context omitted.

Shooting down an airplane at 20km altitude requires an expensive rocket and reveals position of the launcher. No, can't use cheap MANPADs for this. My gut feeling tells me this airplane is potentially cheaper than a rocket, so if it is shot down, it is a win already. If it detects launcher position while rocket is on the way it is even bigger win. Potentially it reveals larger radar position too, that's another win.…

I don't know how they communicate with FPV drones 20-30Km away on the battlefield. They can't use cellphone networks, because they're compromised. I doubt you can fit a starlink terminal to a drone. But this thing could be fitted with frequency-hopping comms, and could control a swarm of attack drones from 70,000 feet. It could also have a backlink to the pilot, allowing him to control any drone in the swarm. I imagi…

The Ukrainians have infact fitted starlink to aerial drones. One of the reasons for their disputes with SpaceX.
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