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The potentially revolutionary Celera 500L aircraft

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Re: The potentially revolutionary Celera 500L aircraft

#91

Post by lightgreen »

Ericson2314 wrote: post #62

Not gonna lie, this week I've read two HN postings about dope planes for rich people (boom, now this)......and news articles detailing a crisis of austerity for the NYC subway. It's really sad to me that we can VC these wild bets on inefficient transport for the few, meanwhile perhaps the most efficient people-mover ever devised for the many is on an entirely politically-caused death bed.

NYC is a very rich city. NYC can definitely afford a better subway.

People come to the voting stations and pick the candidate with the most important agenda for them. Obviously, the NYC subway does not seem to be the largest issue.

If you want to blame rich people for that, well, welcome to the USSR.

Re: The potentially revolutionary Celera 500L aircraft

#92

Post by tomcam »

aeternum wrote: post #83
Gravityloss wrote: post #74

Earlier quoted context omitted.

I think this airplane is pressurized, flies very high and has a big turbocharger. And it has a diesel engine, so the MPG means a different thing - diesel is denser. It's optimized differently to the experimentals, and it's more useful commercially. Flying high avoids a lot of weather issues. You don't have to cancel flights because of weather. The drag from the streamlined shape is very low. It's just a textbook mini…

While the shape might work well for drag, looks matter, especially with private aviation. This thing just doesn't look very sleek or impressive. Cost to repair and insurance is also a very significant part of the cost, so if this is difficult to land or costly to repair, it won't be very popular.

If it comes even close to the claimed efficiency it could look like a 1961 Skoda and nobody would care

Re: The potentially revolutionary Celera 500L aircraft

#93

Post by nl »

qzw wrote: post #58
scarier wrote: post #45

For some perspective, the Scaled Composites Catbird (powered by a 210-hp V6) achieved just over 20 mpg at 200 mph with close to 1000 lbs of payload (it could carry a pilot and four passengers) in the late '80s and early '90s. Amateur-built experimentals have achieved upwards of 50 mpg in realistic flying conditions, but they generally tended to be tandem-seat designs with minimal frontal area and low-powered engines.…

Definitely some extraodinary claims that will require extraordinary evidence to prove. Especially getting 20+ mpg for 4500 miles, while flying at 450mph, which is near the top end of what piston/propeller aircraft are capable of. For reference, the P51 (one of the fastest fighters of WWII) had a comparable top speed. The Piaggio Avanti [0] has a somewhat similar design and top speed (460 high speed cruise), but has t…

Much of the improved efficiency comes from the engine[1], which claims "50% lower fuel burn compared to turbine engines in the same power category".

The engine company is German and so we can make lots of jokes about German companies' fuel efficiency claims I guess.

Nevertheless, it has been around since 2012 and is used in a few planes already, so presumably there is some measurable improvement there or they'd have taken the claim down by now?

For comparison, this engine has a Specific fuel consumption of 210 g/kW/h, while a P&W PT6A-6 (older, slightly more powerful: 431 kW vs 368kW) has 0.408 kg/kW/hr[2]

[1] https://red-aircraft.com/?lang=en

[2] http://www.all-aero.com/index.php/contactus/64-engines-power...

Re: The potentially revolutionary Celera 500L aircraft

#94

Post by skykooler »

alfalfasprout wrote: post #61

It's still a GA aircraft though... so you still have to deal with all the BS. If you don't own it yourself then you need to pay a pilot (though with the recent downturn there's no shortage of pilots). There is absolutely no way many people will try and get their pilot's license. The FAA written test for a PPL may be easy compared to IR but it's still not a walk in the park. The checkrides are very strict nowadays too…

That said, it would definitely be cheaper to certify a pilot on this than on a business jet, since the flight hours for the aircraft cost much less.

Re: The potentially revolutionary Celera 500L aircraft

#95

Post by scarier »

Robotbeat wrote: post #90
scarier wrote: post #86

Earlier quoted context omitted.

All of that helps, but a pilot flying an unpressurized experimental can still get up to 17.5k' VFR on oxygen. Assuming the Celera cruises around FL250, you're talking the difference between ~300KTAS and ~350 KTAS at 200 KIAS. I'd be shocked if they cruise much above FL300, regardless of how high their service ceiling proves to be--for anything other than a really long-distance flight, they'll spend too much time clim…

This is optimized for really long distance flight, thousands of miles. That’s the whole point. Cruise height of 30,000ft, I think. Why would you be shocked by flying at heights comparable to typical jet aircraft flying similar distances?

I wouldn't be surprised by a long-range cruise altitude around FL300, but if it was FL450 I'd be extremely surprised. If the plane achieves the advertised 20mpg on a hypothetical 4500-mile flight at FL500, but only makes a small fraction of that on a more realistic 400-mile regional hop at FL210, it's not really a practical success.

(Aside: the advertised range seems like drastic overkill for something designed to offer a cheap alternative to private jets--it's difficult to overstate how much it sucks being cooped up in a tiny plane for over 11 hours, even if you have the luxury of rich leather seats, can stand up in the cabin, and don't have to pee into plastic bags. Even if a family wants to charter a private jet from LA to the Bahamas for a long weekend, it'd be miserable trying to one-leg it.)

Re: The potentially revolutionary Celera 500L aircraft

#96

Post by scarier »

nl wrote: post #93
qzw wrote: post #58

Earlier quoted context omitted.

Definitely some extraodinary claims that will require extraordinary evidence to prove. Especially getting 20+ mpg for 4500 miles, while flying at 450mph, which is near the top end of what piston/propeller aircraft are capable of. For reference, the P51 (one of the fastest fighters of WWII) had a comparable top speed. The Piaggio Avanti [0] has a somewhat similar design and top speed (460 high speed cruise), but has t…

Much of the improved efficiency comes from the engine[1], which claims "50% lower fuel burn compared to turbine engines in the same power category". The engine company is German and so we can make lots of jokes about German companies' fuel efficiency claims I guess. Nevertheless, it has been around since 2012 and is used in a few planes already, so presumably there is some measurable improvement there or they'd have…

Still, a plane with half the aerodynamic drag and twice the BSFC is only getting 4x the fuel efficiency, not the ~10x they're claiming. Even if they're making a bit of "free" thrust from their cooling system (which has been a thing since WWII), I don't see what accounts for the rest, even ignoring that the Celera likely has a significant increase in frontal area due to the standing-height cabin.

Re: The potentially revolutionary Celera 500L aircraft

#97

Post by sowbug »

joshyeager wrote: post #19
karlkatzke wrote: post #11

It seems to require a pretty seriously long runway to take off. On a warm day, we’re talking international airport length runway. While pistons are cheaper than turbines, that’s because almost all of the approved pistons on the market use 1940s or earlier technology. They are very, very, very simple machines. They are still extremely expensive. This engine is very complicated, even for an automotive engine. It’s got…

The article says its typical takeoff run is 3300 feet, which is about half what a 737 needs. I don’t know a lot about airplanes, but that seems like a pretty short runway length requirement. What am I missing?

A typical small airport might have a 2,500-foot runway, and you never want to come anywhere close to using all that up. It's often desirable to use small airports that are closer to your origin and destination, which could save several hours of travel time before takeoff and after landing. Usually there's also less air traffic to contend with, no landing fees, and cheaper aircraft parking.

Re: The potentially revolutionary Celera 500L aircraft

#98

Post by travisgriggs »

Nice and all, but I just got my private pilots wings a month and a half ago. I've looked at planes. I could buy an fleet of old pipers and burn 9gallons an hour throwing a plane away a year for what just one of these will probably cost. The tech is cool, but I would love to have something robust and cheep for the private pilots out there.

Re: The potentially revolutionary Celera 500L aircraft

#99

Post by thunderbird120 »

scarier wrote: post #86
Gravityloss wrote: post #74

Earlier quoted context omitted.

I think this airplane is pressurized, flies very high and has a big turbocharger. And it has a diesel engine, so the MPG means a different thing - diesel is denser. It's optimized differently to the experimentals, and it's more useful commercially. Flying high avoids a lot of weather issues. You don't have to cancel flights because of weather. The drag from the streamlined shape is very low. It's just a textbook mini…

All of that helps, but a pilot flying an unpressurized experimental can still get up to 17.5k' VFR on oxygen. Assuming the Celera cruises around FL250, you're talking the difference between ~300KTAS and ~350 KTAS at 200 KIAS. I'd be shocked if they cruise much above FL300, regardless of how high their service ceiling proves to be--for anything other than a really long-distance flight, they'll spend too much time clim…

Their patent application implies that it is optimized for cruising at 50,000 feet.

[1]https://patentimages.storage.googleapis.com/3b/f3/9a/928c862...

Re: The potentially revolutionary Celera 500L aircraft

#100

Post by desdiv »

qzw wrote: post #58
scarier wrote: post #45

For some perspective, the Scaled Composites Catbird (powered by a 210-hp V6) achieved just over 20 mpg at 200 mph with close to 1000 lbs of payload (it could carry a pilot and four passengers) in the late '80s and early '90s. Amateur-built experimentals have achieved upwards of 50 mpg in realistic flying conditions, but they generally tended to be tandem-seat designs with minimal frontal area and low-powered engines.…

Definitely some extraodinary claims that will require extraordinary evidence to prove. Especially getting 20+ mpg for 4500 miles, while flying at 450mph, which is near the top end of what piston/propeller aircraft are capable of. For reference, the P51 (one of the fastest fighters of WWII) had a comparable top speed. The Piaggio Avanti [0] has a somewhat similar design and top speed (460 high speed cruise), but has t…

>Especially getting 20+ mpg for 4500 miles, while flying at 450mph

That's not what they're claiming though. They're claiming that:

1. 20+ mpg

2. maximum speed of 450 mph

3. range of 4500 miles

are possible individually, not that 1+2+3 are possible all at the same time.

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