[HN Gopher] Launch HN: H3X (YC W21) - High power density electri...
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Launch HN: H3X (YC W21) - High power density electric aircraft
motors
Hey HN! I'm Jason, one of the co-founders at H3X
(https://www.h3x.tech). We are building the lightest electric
propulsion systems in the world. Our first product is a 250kW
(330HP) integrated motor drive in a 18kg (40lb) package. It
combines the electric motor, inverter, and gearbox into a single
unit, resulting in an ultra-high-power density solution for
electric aircraft (and other mass sensitive applications). In
terms of electrification, we believe the aircraft industry is where
automotive was ten years ago. There are many companies working on
eVTOL and single-seaters, but very few are working on large
commercial single-aisle electric aircraft such as a 737. This class
of aircraft is absolutely critical to electrify as it accounts for
the most passenger-miles [1] and is the biggest slice of the pie in
terms of aviation emissions. Beyond the environmental impact, there
are huge potential cost savings from both fuel (or lack thereof)
and reduced maintenance for airlines. Aircraft are very mass
sensitive so there are two main technology challenges that need to
be solved to enable this class of electric aviation - (1) High
energy density and efficient energy storage (batteries, hydrogen
fuel cells, etc.) (2) Light, efficient, and high-power density
electric propulsion systems (electric motors, power electronics,
gearbox) There are many people working on (1) and great strides
are being made [2][3]. We are focused on solving (2). A study done
by the DOE determined that for a 737 to complete a five-hour
flight, the propulsion system must be >12 kW/kg [4]. Today, best-
in-class systems have a power density of 3-4 kW/kg. With our first
product, we are targeting 13 kW/kg, making it an attractive
solution for near-term Advanced Air Mobility (AAM) applications as
well as an enabling technology for the aviation industry to enter
the next stage of electrification. There are some cool things we
are doing with the electromagnetics, power electronics, and the
integration between the systems to get to the 13 kW/kg. There is
not a single magic bullet, but rather a combination of multiple
technological advances - 3D printed copper stator coils, high
frequency SiC power electronics, and a synergistic cooling system
to name a few. Our origins in electrification stem back to our
college days where we built Formula-style electric racecars (s/o to
Wisconsin Racing FSAE!). During year 1 of the program, we got so
fed up with our COTS motors and inverters, we decided to go clean
slate and build our own from the ground up the following year.
Those were super happy fun times. Lots of dead IGBTs and all-
nighters in the shop, but in the end, we got everything working and
delivered! It was a true test of resilience and taught us how to
GSD. Great preparation for starting a company. This led us to grad
school and it became apparent during this time that the electric
aircraft industry was a sleeping giant ready to be woken. We felt
uniquely positioned to capitalize on this opportunity, so after
about a year in industry, we left our full-time jobs and went all
in. We've got a long road ahead - aviation is tough, there's no
denying that. In addition to the engineering challenges, there are
also major certification barriers. However, CO2 is a serious
problem and right now the major aviation players don't have a
compelling plan to meet the goals laid out in the Paris Agreement.
Innovation needs to come from the outside and that's what we're
doing at H3X. I'd love to hear your guys thoughts and would be
happy to answer any questions you have. Sources: [1]
https://www.transtats.bts.gov/tables.asp?DB_ID=130 [2]
https://www.theverge.com/2020/9/22/21449238/tesla-electric-c...
[3] https://hypoint.com/, https://www.plugpower.com/ [4] ASCEND
DE-FOA-0002238
Author : jjsylvestre
Score : 122 points
Date : 2021-02-22 14:11 UTC (8 hours ago)
| tlb wrote:
| 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 would let you double the weight of the motor.
|
| - (My analysis is invalid if you need much higher peak power than
| cruise power.)
|
| I'm curious how you optimize the entire system for such trade-
| offs.
| serjester wrote:
| 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.
| mliben wrote:
| A simple physics-based plane model (like the one we made to
| understand vehicle-level impact of our technology
| development) dictates that the range-optimal cruise speed is
| proportional to 1/sqrt(air density), so it makes sense that
| the blackbird was more efficient at high speed when at high
| altitudes (admittedly, this simple model is subsonic, and
| there are a lot of other factors for supersonic flight).
|
| Since having lower air density also means you need a higher
| lift coefficient (angle of attack) to produce the required
| lift, and then you have more lift-induced drag (which goes
| with the square of the lift coefficient). I think air density
| more or less washes out when it comes to its impact on range.
| That being said, you cover the full vehicle range at a higher
| velocity at higher altitudes, so it certainly seems like
| there would be significant benefit from a travel-time
| perspective.
|
| All that being said, there are significant high voltage
| insulation challenges at higher altitudes, which is something
| we are working on.
| jjsylvestre wrote:
| This is an excellent question. For narrow body aircraft we've
| studied, they require high propulsive power during the takeoff
| and climb phases, and a fraction of the peak propulsive power
| during the cruise phase. One aircraft we looked at required
| 30-35MW during takeoff and ~10MW during cruise.
|
| So, thrust power and system level power density (kW/kg) are
| critical during takeoff/climb and cruise efficiency is
| important for minimizing energy consumption.
|
| Like Audunw mentions, its very application dependent as well.
| It all boils down to the propulsion system mass fraction. For
| lower PSMF, efficiency matters more once you are above a
| certain power density. For higher PSMF, power density matters
| more. There is an optimal balance of efficiency vs. specific
| power for every aircraft. We can "tune" our technology
| relatively easily depending on what that balance is to maximize
| range.
|
| I'll let my cofounder Max chime in since he does a lot of
| vehicle-level architecture and optimization. He's been doing
| some studies for rotorcraft and planes to look at how specific
| power and efficiency impact range/endurance so I'm sure he can
| expand on my answer a bit.
| mercurywells wrote:
| > One aircraft we looked at required 30-35MW during takeoff
| and ~10MW during cruise.
|
| Do you envision some airframes to include assisted take-off
| technology? (JATO and the like, even catapults)
| mliben wrote:
| I think most forms of assisted takeoff technology would
| reduce electrical power requirements for takeoff, but not
| put much of a dent in the climb power (unless you can
| catapult/ JATO all the way up to cruising altitude, which
| would be challenging). Since climb power is still
| significantly higher than cruise power, and is effectively
| thermal steady state for these components (10-20min), it
| would still drive the propulsion system sizing.
| hbrav wrote:
| You could have another aircraft tow you, like gliders
| sometimes do. Doesn't seem terribly practical though.
| omgwtfbyobbq wrote:
| 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.
| mchusma wrote:
| 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.
| mliben wrote:
| Not exactly what Talyn Air is doing, but along the same
| lines- separating out the "lift/climb" vehicle from the
| "cruise" vehicle. It can actually be a very compelling
| design!
| throwawayboise wrote:
| You still need enough reserve power at the end of a
| flight to do a rejected landing/go around, or you won't
| get certified. If you are relying on some kind of
| catapult, rail gun, or rocket assist to take off, not
| sure how that happens.
| audunw wrote:
| > 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.
|
| I guess that depends on what kind of airplane you are making.
| If you're just making the same kind of airplanes we've been
| making with ICE, but with electric motors and batteries
| instead, you're probably right.
|
| But if you're making an electric airplane from scratch, there's
| a lot you can do if you have a really light motor, which can
| drastically reduce drag.
|
| Look at Maxwell X-57 for instance:
| https://www.youtube.com/watch?v=-HvZ7c0F9ik
|
| If you're going to have lots of motors on the wings, they
| better be as light as possible.
|
| I'm guessing the increased efficiency from a design like that
| can easily be as important as the efficiency of the motor
| itself.
| mliben wrote:
| These are all great points- everything is very interconnected
| in these vehicles, and there is a lot of potential upside in
| high power density distributed propulsion (like on the
| Maxwell).
|
| In characterizing the vehicle-level benefit of power density,
| it is definitely important to consider the X kg of structure
| required to support 1 kg of motor/inverter/gearbox/etc.
| lambda_obrien wrote:
| When can we buy a motorcycle with this in it? I'm joking, but you
| know someone wants to kill themselves that way.
|
| On a more serious note, what other applications do you intend for
| these?
| mliben wrote:
| haha yeah, 100% I'm sure someone is already considering it...
| (looking at my co-founder eric, he loves motorcycles)
|
| We have received significant interest for high performance
| ground and marine applications, which we plan to leverage in
| the short-term as a way of getting lots of in-situ run-time for
| our technology without the hurdles of certification. We will be
| pursuing the long road to certification in parallel.
| jjsylvestre wrote:
| Also, cargo UAV is a big one right now. Many UAM companies
| are using this as a stepping stone to start generating
| revenue while they certify their aircraft.
|
| Marine is a big one though.. especially in Scandinavia. Lots
| of interest in electrifying boats and ships there.
| papertokyo wrote:
| Is the scale of the engine for marine applications very
| different to aviation? Ferries usually have huge hulking
| diesels so I'm curious what the equivalent electric
| powertrain is like.
|
| I'm also assuming that a scaled down version would be ideal
| for personal watercraft?
| lambda_obrien wrote:
| In marine use, as a former ship driver (naval, not
| commercial, so needs could vary), I would prefer a larger
| number of small engines I can vector rather than one or
| two larger engines. It removes the need for tugs from
| both the maneuverability standpoint since you have
| vectoring and the safety standpoint since you could have
| redundant systems.
| spockz wrote:
| Don't many modern ships already have this? I recall
| watching "Big Ships" or some such on Discovery Channel
| about 15-20 years ago where they explained ships already
| having multiple stern and aft, starboard and port, "pods"
| either with jet streams or rotors.
| lambda_obrien wrote:
| Sure, but having driven ships with those, they're not as
| maneuverable as they could be. It takes time to deploy
| the pods and often they aren't available at high speed.
| jjsylvestre wrote:
| We are planning to add a MW-class machine to our
| portfolio in the next five years which could serve as a
| nice replacement for the dirty diesel engines on these
| larger ships.
|
| Looking at Taiga Motor's electric jet ski, 250kW would be
| a bit on the high-side. It would also be a very expensive
| jet ski :) https://taigamotors.ca/watercraft/
| hbrav wrote:
| Hey, my neighbor had a small home built plane that was
| powered by an old 2 cylinder generator engine. Maybe you
| should sell yours as generator engines too?
|
| (Yes I'm kidding. I know. I'll stop trying to trick
| thermodynamics.)
| cashsterling wrote:
| I worked in a start-up doing High Altitude Solar powered UAV's
| (ultra-light carbon fiber airframes, etc.)... your motors would
| have been awesome for that. Flying above 50k feet has a host of
| challenges.
|
| Wish you guys a bunch of success...exciting times.
| jjsylvestre wrote:
| Thanks! Yes, high-altitude UAVs is a great application for our
| motors. We're developing a new insulation system for our coils
| so we have spent a lot of time looking into the challenges high
| altitude poses - corona, cooling, all sorts of fun stuff. Lots
| of altitude chamber testing in our future!
| fallingmeat wrote:
| First hires should be people with strong SAE-ARP4754A and SAE-
| ARP4761 experience. Get your safety assessment correct first.
| Understand how to build a FADEC function with appropriate
| development assurance and hardware reliability. Then build your
| extended team (or outsource). Good luck!
| choeger wrote:
| 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.
| jjsylvestre wrote:
| Yeah this is definitely a market we're looking into - both KERs
| and Formula E drive units. Great product-market fit.
| SomeHacker44 wrote:
| Thanks for writing this up!
|
| Ad the pilot of the plane with two 285HP piston engines with an
| MTOW around 5,700 pounds, I am curious: what kind of endurance
| could I get if I replaced my fuel tanks with about 1000 pounds of
| batteries and used your motors? Assume operating at 225 HP during
| climb, cruise and descent and full power during takeoff and
| initial climb out (5 minutes or less). Thanks! (Reference Cessna
| 310R for more details.)
| ducktective wrote:
| 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 you'd recommend for hardware/engineering
| related startups?
| HeyLaughingBoy wrote:
| 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.
| jjsylvestre wrote:
| 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
| throwawayboise wrote:
| I'm not in the field, but from my perspective, aviation is
| super, super conservative. That is one of the reasons why we
| have GA still using leaded gasoline in engines that are
| largely unchanged from the 1950s. F1 is basically the exact
| opposite, they are pushing the bleeding edge of technology
| all the time.
| alexar wrote:
| 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
| jjsylvestre wrote:
| 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.
| fallingmeat wrote:
| You may know this, but your motor will likely (should) be
| certified separately from the aircraft.
| alexar wrote:
| Why aviation?
|
| Why design first (solution looking for problem)?
| balfirevic wrote:
| If you don't mind sharing - what is the airgap diameter
| (presuming it's a radial flux motor)?
| mliben wrote:
| For our technology demonstrator, we have a pretty small rotor.
| Future direct drive designs (typically higher power as well)
| will have much larger diameters.
|
| I can't be too specific, but you can probably get an idea of
| the rotor size from the preliminary datasheet (and/or CAD
| model) that you can download from our website. We have
| dimensions of the outside of the unit. Remember that the
| inverter is in there as well!
| airbreather wrote:
| I have more questions, why are you not using silver, around 106%
| better conductance of electricity, but also a better conductor of
| heat?
|
| And cooling, lots of big electrical plant uses H2 for a cooling
| medium as it has about 22 times better heat transfer than air - I
| can see the peroblems, but you can't light up 100% H2, it's when
| it gets some air with it is the problem.
|
| I actually have a bucket load more, I am Elec Eng/Func
| Safety/Systems Integrator/Embedded guy and many years ago did my
| final engineering project on a software package to design high
| frequency inductors optimised for weight or efficiency, for space
| use. So all in all I am super interested to see how you go and
| what you can squeeze out. Will you run a blog or update of some
| kind?
|
| May your end copper (silver) be short, if you have any.
| mliben wrote:
| Silver is crazy expensive compared to copper, and the tradeoff
| isn't worth 6%. Also, 3d-printing pure copper is relatively
| new, and I'm not sure there is as much of a business case for
| 3d-printing silver (from the perspective of the companies
| making these metal AM machines), since the demand is lower
| because of the cost. Lastly, there are actually some loss
| mechanisms in the motor where the lower resistivity of silver
| would actually hurt you (proximity effect from flux crossing
| through the stator conductors, producing eddy currents).
|
| We want to start simple with cooling, hence the water/glycol.
| There certainly could be some opportunity to use something
| different (maybe with certain fuel cells and liquid hydrogen
| already onboard?). Regardless, the thermal resistance from
| hotspot to coolant is dominated by conduction resistances
| inside the motor, and is less a function of the convection
| resistance from the housing to the coolant.
|
| We will be sending out a newsletter occasionally, there should
| be a link at the bottom of our website.
|
| Thanks for the questions!
| [deleted]
| Giorgi wrote:
| So... in layman terms, can I buy this, strap on the Boeing 737
| instead of turbine and fly? Will I need 2 units, for each wing?
| Or how does it work?
| mliben wrote:
| Well, you would need significant energy storage either in the
| form of batteries or hydrogen + fuel cells as well :)
|
| Our technology demonstrator is a 250 kW machine, but we have
| plans to scale up to the megawatt class in the next few years.
| Like Jason mentioned elsewhere in the thread, tens of megawatts
| are required for a narrow-body jet like the 737. There is
| significant aerodynamic benefit from having multiple
| distributed propellers/fans as opposed to two-four big ones,
| and likely this is the path forward for electrification of
| these larger planes, i.e. a lot more than 2-4 units, with
| single-digit megawatt capability per unit.
| tin7in wrote:
| An interesting anecdote I listen to during a conference on eVTOL.
| A long flight with an electrified 747 will require more power
| from the grid than Heathrow's electricity consumption for half a
| day.
| mliben wrote:
| Certainly. Infrastructure is actually one of the biggest
| technological challenges for flight electrification. This is
| one area where hydrogen / fuel cell might have a leg up since
| it can physically/geographically decouple the power
| distribution from the airport itself (whereas for battery
| electric, unless you want to swap tens of tons of batteries
| between flights, you need charging infrastructure at the
| airport itself- and charging many 747-sized planes
| simultaneously at C-rates of at least 1 would require an
| obscene amount of power).
| gene-h wrote:
| Are ya'll doing any crazy multiphysics topology optimization to
| optimize magnetic fields, heat transfer, and fluid flow?
| mliben wrote:
| We take the 80/20 approach here. We start with analytical
| design (can be done pen on paper, but typically happens in
| excel/etc) to get a high-level view on the "continent" of
| design possibilities. This can be done readily with magnetic
| circuit models and thermal resistance networks.
|
| From there, we identify the best high-level design traits and
| begin some optimization work to get most of the way to a fully-
| optimized solution (this is more FEA-based, both mechanical,
| magnetic, and thermal). This gets us climbing up the right
| "mountain" on the continent.
|
| At this point, we put the pens down and start building
| something, because we will learn more building a prototype and
| iterating than we will spending too much time in simulation-
| land.
|
| In parallel, we have been putting together a workflow to co-
| optimize the design across mechanical, magnetic and thermal
| simultaneously. Thus far the jump across each discipline has
| been a bit more on the manual side, but automatic co-
| optimization is a long term project, and would get us to the
| "peak" of the mountain.
| chrisdalke wrote:
| This is really exciting, congrats on the launch! Exciting to see
| engineers coming from college engineering teams like FSAE -- I
| was a member of a solar boat racing team, which is a very similar
| problem space and also relies on "stacking efficiencies" in your
| drivetrain system.
|
| If you don't mind, I have a few questions about how you collect
| data and evaluate the performance of your motor quantitatively.
| Do you have any particular software stack for data collection? I
| see the motor communicates over CAN -- Is that just to send
| control signals, or do you also expose sensor readings like
| temperature, power input/output, etc? Lastly, did you need to
| write any custom software to collect/visualize motor performance
| and what does that look like?
|
| The reason I ask is because I'm in the early stages of building a
| data collection & analysis platform for experimental hardware
| (https://www.telemetryjet.com/), targeted at small engineering
| teams or individuals. I don't want to focus too much on what I'm
| building (this is your thread!) so I'll just say in general I'm
| really interested in learning more about how small engineering
| teams like yours collect & utilize data in the engineering
| process.
|
| Congrats again on the launch.
| emaciolek wrote:
| CAN is pretty typical interface for inverters & drives. We
| communicate the commands via CAN and receive currents, temps,
| speed, torque, and errors back via CAN. We are using PCAN
| systems at the moment. In the past, GUIs that I have used are
| Kvaser, Vector Canape, ATI Vision, and LabView. A lot of our
| post processing is done in MATLAB, Excel, or python. Feel free
| to reach out directly if you would like more insight.
| fallingmeat wrote:
| @jjsylvestre - what are your thoughts on ZeroAvia?
| jjsylvestre wrote:
| Love what they are doing. I would consider them one of the
| leaders in the pack right now. Val has a practical vision to
| get to market on a timeline that is very compelling. Hydrogen
| FC is very promising for long-range flight applications due to
| its high energy density so I think they are focusing on the
| right things.
| zulln wrote:
| https://heartaerospace.com/, YC W19, is building a full electric
| plane if anyone else became interested.
| fudged71 wrote:
| Which DMLS platform are you using to print these components?
| ascales wrote:
| The 480nm number is really impressive at this size. Especially at
| 5000rpm with the 4-1. Compared to a ICE motor that weighs ~200kg,
| you effectively free-up 40kwh~80kwh (80 if you believe the
| 400w/hr claim that Tesla makes) of battery capacity right there.
| I think there's still a long way to go, but seeing things like
| this and planes like Pipestrel's electric planes, GA electric
| planes are more and more feasible.
| mliben wrote:
| Absolutely. It's easy to focus on comparing what we are working
| on with the other (few) electric solutions being built out
| there, but compared to combustion engines the specific power is
| a big step change. When you combine that with improved specific
| energy (either from cutting-edge batteries like what
| QuantumScape is working on, or cutting-edge fuel cell systems
| like what HyPoint is working on), you can see the path to GA
| electric planes and even small business jets is not far off.
| airbreather wrote:
| 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.
| jjsylvestre wrote:
| Love the brainstorming. As you mentioned, "decoupling" the
| cruise mode from the takeoff mode could make a lot of sense.
| One of the most innovative and feasible solutions I've seen is
| from a former YC company called Talyn Air
| https://www.talyn.com/
|
| They have a nice animation showing the lifter and the cruiser
| vehicles.
| mjmahone17 wrote:
| An electric trolley plane? Basically add a rail in the runway
| that powers the plane through take off, with the batteries
| engaging once in the air.
| airbreather wrote:
| Or, more like an upside down tram, get the first big bunch of
| acceleration from ground electricty that doesn't count for
| weight.
| keizo wrote:
| Can I get one to put in a jet ski and or electric boat?
| alexar wrote:
| 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.
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