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this post was submitted on 11 Oct 2024
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No, what I'm talking about isn't steaming bullshit fresh from the bovine's ass.
What is the major complaint people have about electric cars? Range, right? Because lithium ion or lithium polymer batteries do not have the energy density per unit volume or unit weight of gasoline. Electric cars are often heavier than their ICE counterparts because they're crammed with so many batteries to make up for the relative lack of energy density, and they benefit from things like regenerative braking. Electric motorcycles often don't have regenerative braking, which is why Kawasaki is right now advertising a $7000 sport bike with a 55mph top speed (65 if you push the boost button) and a range of 41 miles (if you don't push the boost button). The Ninja 250 I bought in 2007 could do 120mph and I routinely went 300 miles between fill-ups with it's ~5 gallon tank.
Meanwhile these folks have a hexacopter that will out-carry and out-run a Robinson R-44 piston-powered helicopter, on Lithium batteries.
Actually just right there, they say a 200 mph cruise speed and a 100 mile range. So that's a 30 minute endurance. To legally fly cross country in the United States, you need to have enough endurance to make it to your first intended point of landing PLUS 30 minutes, and that's day VFR minimum fuel when operating under Part 91. Are you telling me it has an hour of battery life but half of that will be in reserve? In something like a Cessna Skyhawk a half hour of fuel is something like 4 gallons of gasoline, or about 24 pounds. How much lithium battery do you need to make ~100 horsepower for half an hour? And mind you, that's cruise power, NOT takeoff power. Which will be a LOT greater than cruise power especially in a VTOL aircraft. I get that it's a tiltrotor and would have airplane-like performance in cruise, but it'll still be more of a bitch to get airborne than a conventional plane.
Anybody want to see me plan a 100 mile flight in a Cessna Skyhawk, figure up how much gas the trip would take, convert that amount of gas to kilowatt-hours and then look up the weight of a Li-Ion battery with that capacity?
I'd also be real interested to know what the secret sauce is to make those propellers that quiet. Yes, electric motors are quieter than gas engines, but the noise from something like an airplane or helicopter is mostly made by the propeller/rotor blades, especially at the tips. By what physics are you going to make something with 6 propellers quieter than something that has one? I bet that thing is going to be louder - and shriller - than an equivalent helicopter. Stand next to a toy drone in flight and explain to me by what magic they're going to make one that seats four make "a barely perceptible sound."
If you're going to tell obvious lies, just say I'm pretty.
The lack of imagination in this post is astounding. In this wall of gibberish you only really made three points: range, excess range, and noise.
Range: evtols are not trying to replace GA aircraft, at least initially. They will start out as air taxis and toys for the ultra rich, but most people dramatically underestimate the rate at which battery technology is improving. Being able to travel 100 miles in 30 minutes without spending an hour on each end dealing with the airport is something unavailable today.
Minimum fuel requirements: rules are meant to serve us, not be handed down from on high. If this does apply to evtols it will be changed. It's a completely different use case. For example the emergency landing options for an evtol are vastly more available than for a Cessna.
Noise: I mean, agreed overall if not in detail. Realistically these things are going to be quieter than a traditional helicopter for sure, but will be higher pitch and swarming around in greater numbers. Annoying AF.
"evtols" are going to BE General Aviation aircraft, just like helicopters are today. The thing I saw in that article would be certified under the currently very empty Powered Lift category. I would be extremely wary, as in "nail his skull to the pavement just in case" wary, of anyone trying to say these machines are anything different than that and should thus be exempt from any FARs. That's the attitude Stockton Rush had. Break out the Ouija board and ask his passengers how that shook out.
100 miles in 30 minutes from any random point to any random point is indeed kind of tricky, A Bell Jetranger can do 150 mph if you really push it. A significantly cheaper Robinson R-44 Raven set a record for piston helicopters at 144mph, more typical cruise speed is 130. Still twice what you'll do in a limousine going down the highway. They still occasionally pound helicopters full of expensive people into hillsides. Break out the Ouija board again and ask Kobe Bryant about his opinions on rotorcraft operations. We've got ~75 years of experience flying civilian rotorcraft. I don't even know how you'd go about getting a powered lift rating on a pilot's license right now; studying for my ground instructor certificate there wasn't even a chapter about them. I had to study hot air balloons and gyrocopters but not powered lift tiltrotors.
You're absolutely right, the rules are meant to serve us. Minimum fuel requirements are one of those rules that keep planes out of neighborhoods when the headwinds are stronger than forecast. I would say they should actually be INCREASED for powered lift or VTOL aircraft because descent and landing is more power intensive than cruise flight as it has to come to a hover under thrust, rather than the gliding flight of a landing airplane. Again, when someone says "These things are full of lots of trendy buzzwords so they shouldn't be held to basic operational safety standards" I say "I'll get the nails, you hold his head to the ground." This is how we end up with a fire in a neighborhood that can't be put out.
For air taxi or other for-hire operations it's going to have to be certified under a standard airworthiness certificate and I don't even know if we have a category for that. I'll also eat my AOPA hat if you can find me an insurance company that will underwrite the fucking thing.
Let me also ask you this, just...try this sniff test: There's a lot of steps between the gas/diesel/turbine airplanes and helicopters we have today, and a battery electric tiltrotor VTOL. Where's the electric helicopter? Where's the electric airplane? Where's the fuel burning VTOL? Surely if there's a market for a machine that can go 100 miles in half an hour with no runway, there's a market for a machine that can go 500 miles in 2.5 hours with no runway. Why aren't they building any of that first as a stepping stone?
Because it's a fucking scam.
Gas engines generally lack the immediate throttle control/thrust response necessary for use in a multicopter. Why didn't we see gas RC quadcopters before electric ones? My sniff smells ok.
Would you want a centralized gas engine powering your 4+ rotors causing them all to fail at once or would you like the complexity of 4+ separate ICE engines trying to work in concert with precise torque output?
I'm suggesting these flying transport firms may be lobbying for change, not that they have a viable business/technology.