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Launch HN: H3X (YC W21) – High power density electric aircraft motors

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31–40 of 169 posts

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#31
post #22

Earlier quoted context omitted.

You could have another aircraft tow you, like gliders sometimes do. Doesn't seem terribly practical though.

That could be a great use case for lighter/smaller electric motors, since a tow plane could take off, assist with takeoff, turn around and land, charge, and repeat. The tow plane wouldn't need as large of a battery pack, but having good power to weight for towing other plants to whatever altitude is very important.

I feel like this is something that drones/100% automated ops can really help with.

Power satellites (basically giant solar arrays transmitting power) are also interesting (https://www.geekwire.com/2020/space-force-will-test-solar-po...).

We could have these complex automated systems to make electric aircraft much more viable, which is cool in theory.

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#32
post #2

Given that the batteries weigh a lot more than the motors, I would have thought that motor efficiency (which scales battery size) was much more important than motor weight. My back-of-the-envelope is: - Assuming 0.4 kWh/kg for batteries, and they have to run for 4 hours, then the total mass per kW is 10 kg (batteries) and 0.08 kg (motor). - A 1% increase in motor efficiency could eliminate 0.1 kg of batteries, which…

Keep in mind that an electric motor isn’t limited by the amount of oxygen in the air. As a result it can fly significantly higher where there is far less air resistance.

Since air density is proportional to the square of the elevation this can lead to significant efficiency gains. Believe it or not, partly as a result of this, the SR-71 had it’s best mpg at peak speeds.

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#33
You guys should contact (some of) the F1 teams. They would certainly love to have more efficient motors in their hybrid PUs. A 5kg saving is literally worth millions in that business. Also Formula-E might be interested, but I don't know how free they are in their choice of material, so you might want to talk to the organizers.

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#34

Oh I've got many questions :) 1- Isn't a HW startup really hard compared to software? Like the ideas are like yet-another-social-media-site or a SASS but in hw one needs to do the embedded programming, the mechanical design, the software, marketing and *then* the novel idea that sells. How do you do it? 2- How do you manage to find the expertise to build a viable product? How did you find investors? 3- Any tips/books…

My perspective might be biased, since for the 30-odd years I've been in industry, I have done mostly embedded systems.

Those things you mention are skillsets: software, mechanical engineering, electrical engineering, etc. Sometimes you find them all in the same person, sometimes you have separate bodies doing each one, but at the end of the day it's a staffing issue.

I'd say it's less that it's "hard" and more that iterations are slower and costly and the less capability you have in-house, the slower it is. If you have a full machine shop and a Stratasys 3D printer onsite, a lot of things can happen faster. If you're doing garden-variety industrial automation, there's far less risk than designing state of the art humanoid robots.

There is a spectrum of difficulty, like everything. In my case, I was doing this stuff freelance, in my spare bedroom at age 25, so it's not that hard.

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#36

Oh I've got many questions :) 1- Isn't a HW startup really hard compared to software? Like the ideas are like yet-another-social-media-site or a SASS but in hw one needs to do the embedded programming, the mechanical design, the software, marketing and *then* the novel idea that sells. How do you do it? 2- How do you manage to find the expertise to build a viable product? How did you find investors? 3- Any tips/books…

1. There are parts that are certainly harder and there is one part I can think of that may be easier.

- Harder: Longer and more expensive iteration cycles, MVP can be expensive, manufacturing and production required to scale, expensive certification

- Easier: Raising money (sometimes) especially if you are a moonshot with a big vision. Good example is Boom Supersonic.

Good news is there has never been a better time to start a hardware company than today. Iteration cycles are becoming shorter due to advances in rapid prototyping and there is a lot of capital available, especially in electric vehicles and sustainable tech.

Peter Thiel talks a lot about this in Zero to One, but much of the innovation that’s been done in the past decades has been in the digital space. We have so many problems that require innovative hardware solutions and I think now we are just beginning to scratch the surface.

2. We all met through Formula SAE in college. This is a great place to meet super talented engineers and is why Tesla, SpaceX, and the other top companies in the world recruit heavily from these programs. It teaches you both the hard skills and the soft skills. If you are still in college, I would recommend getting involved in teams like this.

3. I haven't really read anything hardware-startup specific, but I love Zero to One and find myself rereading it all the time.

Would love to hear other peoples thoughts on this as well. Good questions

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#37
post #35

Why assume that the future aircraft fundamental design has to remain same and electrify the trusters? Current aircrafts have evolved into their current shape from restrictions and capabilities

The big advantage of using existing airframes is that you dramatically reduce certification costs and commercialization time. If you can "retrofit" an existing airframe with electric propulsion, then you can get to market a lot faster.

You're absolutely right though - changing the airframe design and moving to distributed propulsion can lead to improvements in aerodynamic efficiency, L/D, and fault tolerance.

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#38
Have you considered to jettison some of the batteries during and/or after take-off?

Probably not just drop them, maybe a controlled glider or similar, plus what are the posibilities for an in the air charge by tether to another plane?

Final super radical idea, have some iflatable high chord wings for take off at low speed high drag and lift, then ditch them somehow once at altitude and can do a anouever with stored height to get speed. (Or a lift blimp).

As you say, the take off is where the problem is.

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#39
Why assume that the future aircraft fundamental design has to remain same and replace the turbofan engine with an equivalent electric motor?

Current aircrafts have evolved into their current shape from restrictions and capabilities of combustion & jet engines.

Re: Launch HN: H3X (YC W21) – High power density electric aircraft motors

#40
post #35

Why assume that the future aircraft fundamental design has to remain same and electrify the trusters? Current aircrafts have evolved into their current shape from restrictions and capabilities

The big advantage of using existing airframes is that you dramatically reduce certification costs and commercialization time. If you can "retrofit" an existing airframe with electric propulsion, then you can get to market a lot faster. You're absolutely right though - changing the airframe design and moving to distributed propulsion can lead to improvements in aerodynamic efficiency, L/D, and fault tolerance.

You may know this, but your motor will likely (should) be certified separately from the aircraft.
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