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The potentially revolutionary Celera 500L aircraft

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Re: The potentially revolutionary Celera 500L aircraft

#241

Post by sirk1882 »

Toutouxc wrote: post #139
sirk1882 wrote: post #116

Earlier quoted context omitted.

And as others have mentioned, it's taken advantage of newer technology that allows six of pistons to be turned off. The engine basically sounds like two in-line six cylinder engines that share many common single engine features but with the ability to shut off one side and use power from the remaining side. So hypothetically, you fly up to altitude and climb using all 12 cylinders, then cruise on six. That could be w…

Naturally aspirated != carb. You can have a naturally aspirated engine with electronic (even direct) injection, or a turbocharged engine with a carburetor, or any other combination.

True. Naturally aspirated simply refers to the lack of a turbocharger/supercharger pressurizing atmospheric air as "boost".

I just wish carbureted was an easier word to spell after not using it for months at time.

Re: The potentially revolutionary Celera 500L aircraft

#242

Post by tonyarkles »

sirk1882 wrote: post #110
dmix wrote: post #102

Earlier quoted context omitted.

Sorry for the amateur question, but why does it take longer to take off in hot places? Doesn’t heat generate lift, like in gliders crossing hilly terrain? Or is it the heat offsetting with the cooler ground that helps, so you’d need a greater amount in hot places?

It has to do with air density. Heavy, cold air will generate more lift since it's "thicker" for lack of a better term. Hot air is less dense. This means it takes more power to move more air. It's easier to maybe think of the air that you breath as a "liquid" like material comprised of a mix of mostly nitrogen, some oxygen and a little carbon dioxide and other gases. That mix changes with temperature and elevation. Ju…

A different way to think about it is the Newtonian approach: your wing is accelerating air particles in a downward direction, and the equal-and-opposite reaction is what (partially) generates the lift on the aircraft. Lower density means there’s fewer particles to deflect downwards in a given volume of air. In a similar vein, a rotation of the propellor accelerates air particles rearward, which results in a forward thrust on the aircraft; fewer particles to accelerate means less thrust.

Re: The potentially revolutionary Celera 500L aircraft

#243

Post by ppf »

sirk1882 wrote: post #240
ppf wrote: post #161

Earlier quoted context omitted.

Removing your energy source (fossil fuel) and replacing with energy storage doesn't fix anything - where does the energy to fill that storage come from? In some hypothetical future where renewable energy is very cheap, it will still be more efficient to use that energy to produce liquid fuel for planes.

ITER. Tritium breeding reactors by feeding it recycled lithium.

Exactly. IMHO nuclear is the only way, if we go down this path. And if we do that, then we mostly don't need to bother with wind/solar/grid storage.

Re: The potentially revolutionary Celera 500L aircraft

#244

Post by Tuna-Fish »

VBprogrammer wrote: post #224
asdfadsfgfdda wrote: post #219

Earlier quoted context omitted.

The layout/payload may be similar to a TBM, but I'm guessing the wing loading and cruise altitude will be higher. So it's definitely feasible to go faster on less power.

Aerodynamic drag is a square relation so the difference in drag there is about 40%. With 65% of the power. I think occam's razor applies here. Either the aerodynamics of reasonably modern aircraft designs leave a huge amount on the table or this startup is telling fibs. There are other reasons to be suspicious, modern diesel engines rely on a large amount of turbo charging to achieve sea level rated power, it's diffi…

> I think occam's razor applies here. Either the aerodynamics of reasonably modern aircraft designs leave a huge amount on the table or this startup is telling fibs.

Aerodynamics of reasonably modern aircraft designs do leave a huge amount on the table. Generally for good reasons, though. The 500L is clearly almost entirely a laminar-flow design, unlike conventional aircraft (including the one you linked). Experience from gliders have shown that a small laminar flow design like this can have less than a third of the drag of what a conventionally shaped design of roughly similar size.

There are two major downsides to designing like this:

Firstly, the shape is entirely determined by physics, leaving very little wiggle room for manufacturing or practical concerns. Without modern composites, cost-effectively manufacturing the frame is impractical.

Secondly, the great drag properties are very dependent on the properties of the skin of the aircraft. Laminar-flow gliders can have their glide ratios halved after accumulating a few too many insects on the leading edge. If you want to fly very high, (as this plane seems to want to), better hope you have an amazing de-icing system, or even a very small amount of ice will trash your aerodynamics.

Re: The potentially revolutionary Celera 500L aircraft

#245

Post by jillesvangurp »

VBprogrammer wrote: post #173
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…

I'm calling bullshit. Compare it to the TBM900 which has a 900hp turbine engine and vastly similar layout. There is no way they can go 60 knots faster on 300 less horse power. And even if they somehow pull off that trick, that short skinny wing will make the MU-2 feel like a safe family minivan.

If they reduce drag, which is exactly what they are claiming to have achieved, that would reduce the amount of horse power needed to overcome that drag. Less HP translates into better fuel economy.

Basically this plane has the engine mounted on the back, which means center of gravity and wing position are quite a bit different. The nose cone looks very streamlined and crucially the wings are in front of the vortex produced by the prop. I'm guessing that that adds up to a bit of reduction in drag. The reason many planes have the engines mounted on the other side probably have to do with things like cooling, engine size, and other practical concerns.

Re: The potentially revolutionary Celera 500L aircraft

#246

Post by VBprogrammer »

Tuna-Fish wrote: post #244
VBprogrammer wrote: post #224

Earlier quoted context omitted.

Aerodynamic drag is a square relation so the difference in drag there is about 40%. With 65% of the power. I think occam's razor applies here. Either the aerodynamics of reasonably modern aircraft designs leave a huge amount on the table or this startup is telling fibs. There are other reasons to be suspicious, modern diesel engines rely on a large amount of turbo charging to achieve sea level rated power, it's diffi…

> I think occam's razor applies here. Either the aerodynamics of reasonably modern aircraft designs leave a huge amount on the table or this startup is telling fibs. Aerodynamics of reasonably modern aircraft designs do leave a huge amount on the table. Generally for good reasons, though. The 500L is clearly almost entirely a laminar-flow design, unlike conventional aircraft (including the one you linked). Experience…

Don't forget low speed handling and stall characteristics.

There are so many places where the practically of this aircraft would fall down. Good luck fitting deicing boots to a wing which needs to be kept so clean polishing it makes a difference.

Also, good luck trying to get an clearence to climb to 60,000ft around any busy international airspace. Regardless of any aerodynamics miracles this aircraft pulls off I'm sure we agree that it's climb performance will be distinctly average. That means it's going to take well over an hour to get up there. 20 mins or more could be spent in the RVSM band (FL280+) where most of the airliners are, expect to be vectored all over the sky while this happens. This is already a problem in something like the CJ2 which like to cruise higher than the airliners but aren't quite as fast. It's climb performance is considerably better than you would expect from this aircraft.

Re: The potentially revolutionary Celera 500L aircraft

#247

Post by VBprogrammer »

jillesvangurp wrote: post #245
VBprogrammer wrote: post #173

Earlier quoted context omitted.

I'm calling bullshit. Compare it to the TBM900 which has a 900hp turbine engine and vastly similar layout. There is no way they can go 60 knots faster on 300 less horse power. And even if they somehow pull off that trick, that short skinny wing will make the MU-2 feel like a safe family minivan.

If they reduce drag, which is exactly what they are claiming to have achieved, that would reduce the amount of horse power needed to overcome that drag. Less HP translates into better fuel economy. Basically this plane has the engine mounted on the back, which means center of gravity and wing position are quite a bit different. The nose cone looks very streamlined and crucially the wings are in front of the vortex pr…

They are claiming improvements across almost all areas. If it flew as fast and as far as the competition on 50% less fuel, that would be amazing. If it flew 60 knots faster in the same fuel and payload, awesome!

However, they are claiming improvements across the board. 3x the range, significantly faster, flies higher, uses less fuel. It doesn't pass a sniff test.

Compare it to the Grob Strato 2c. Notice how long the wings are by comparison? This is a feature of nearly all subsonic high altitude aircraft. Also notice the how long the props are on the Grob, another feature of high altitude aircraft conspicuously missing on this aircraft.

Pusher aircraft are not new. In fact they are as old as powered aviation itself. They generally aren't significantly more efficient.

https://en.m.wikipedia.org/wiki/Grob_Strato_2C

Re: The potentially revolutionary Celera 500L aircraft

#248

Post by sunstone »

rhombocombus wrote: post #238
sunstone wrote: post #209

Earlier quoted context omitted.

This airplane has a "2 in 1" engine. Two separate engines running on one physical engine block. So there is some engine redundancy.

yes but that really only matters if the second "engine" produces enough power for maneuvering if the first one fails. Plus, there is still mechanical interconnectedness so it isn't truly redundant. That said it is likely far safer than a traditional twin, the axiom with those is if you lose one engine the second will fly you all the way to the scene of the crash.

There's a link to the motor manufacturer in the article (but it's down right now). As I recall the two motors are identical with no common parts other than the engine block.

Re: The potentially revolutionary Celera 500L aircraft

#249

Post by karlkatzke »

Shivetya wrote: post #175
karlkatzke wrote: post #81

Earlier quoted context omitted.

One engine, a turbocharged V-12.

which pretty much keeps it restricted to overland only. it took a long time for the FAA to permit twins to fly across the ocean? ETOPS (Extended-Range Twin Engine Operational Performance Standards) is just what it says, twin engine but is there any possible means a passenger carrying single engine could get certification? Now as an unmanned cargo drone it might get this permission.

You can fly a single over the ocean, you just have to carry extra equipment.

Re: The potentially revolutionary Celera 500L aircraft

#250

Post by epicureanideal »

EricE wrote: post #206
Someone1234 wrote: post #44

Earlier quoted context omitted.

Only if they don't replace them with even larger digital "windows." There's also been work towards electronic windows in aircraft.

I could see airlines charging more for "thrill" planes that have 360 immersion "windows" wrapped all around you. Wonder Woman eat your heart out! (Her flying in that invisible jet in the cartoons always freaked me out when I was a kid)

Or special flights where the windows make it seem like you're flying into space and landing on Mars.
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