29 May 2025, 16:12 [ UTC - 5; DST ]
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 10:55 |
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Joined: 05/17/10 Posts: 4007 Post Likes: +2029 Location: canuck
Aircraft: x23mouse
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Username Protected wrote: I'm a little late to this discussion, but have been aware of the Celera for a while. I just read an article that popped into my news feed today. Quote by the company CEO: He describes the aircraft as "... four to five times the efficiency of other turboprop aircraft, and seven to eight times the efficiency of jet aircraft" -William Otto Jr., CEO Does this mean that it uses 10-12.5% the fuel of a jet yet still flies just as fast or faster, and has the same range or greater? In the same article the plane is described as being able to fly 400 knots and have a range of 4,500 miles. I find these to be dubious claims. Does anyone know for sure if the Celera follows the same laws of physics as other airplanes? Link to the article: https://www.cnn.com/travel/article/celera-500l-business-aircraft-future/index.htmlNot much in the way of details here where it counts Quote: The Celera 500L first flew in 2018 and has since completed about 50 test flights. So far it has only reached a top speed of about 180 miles-per-hour and an altitude of 17,000 feet, That with 500+ HP then Quote: but a more powerful version of the engine, to be installed soon, will enable faster speeds and higher altitudes, closer to 40,000 feet. ---- to a speed of 460 miles-per-hour from 180 miles-per-hour and an altitude of 17,000 feet to 460 at 40,000 feet with?? "a more powerful version of the engine" from October 28, 2013 https://www.flyingmag.com/aircraft/dies ... evolution/Quote: because they lack an ignition source to keep their fires lit, diesels are restricted in how high they can fly, even with twin turbochargers and hot glow plugs ----- The latest Diamond DA42-VI with its twin Austro diesels and supplemental oxygen is a prime example. It has a service ceiling of just 18,000 feet — which also happens to be the single-engine ceiling for the airplane.
Diamond says it has flown the DA42’s Mercedes-Benz-produced Austro engine to 30,000 feet without ill effect, but for now they are limited by certification from venturing into the rarefied air of the flight levels. Diesels can be prone to flaming out at high altitude where the air is less dense — if it’s cold enough and the air is thin enough, a successful restart could be in doubt. ---- jet-A, jet-A-1 and even straight diesel fuel. Of course, when it’s cold, diesel fuel can turn to Jell-O. Without a fuel preheater or recirculation system, that could pose problems at extremely low temperatures. If you’re going to be flying where it’s really cold with an aero diesel, it’s probably best to go with jet-A mixed with Prist anti-ice additive — as long as it’s approved for use in your engine. https://www.pprune.org/flight-testing/5 ... itude.htmleg some restart requirements for turbines https://www.easa.europa.eu/sites/defaul ... t_PUBL.pdf
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 11:44 |
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Joined: 12/10/07 Posts: 34803 Post Likes: +13386 Location: Minneapolis, MN (KFCM)
Aircraft: 1970 Baron B55
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Username Protected wrote: Not much in the way of details here where it counts Quote: The Celera 500L first flew in 2018 and has since completed about 50 test flights. So far it has only reached a top speed of about 180 miles-per-hour and an altitude of 17,000 feet, That with 500+ HP then Quote: but a more powerful version of the engine, to be installed soon, will enable faster speeds and higher altitudes, closer to 40,000 feet. ---- to a speed of 460 miles-per-hour from 180 miles-per-hour and an altitude of 17,000 feet to 460 at 40,000 feet with?? "a more powerful version of the engine" Sounds a lot like Peter's "We'll fix that in the production version" plan.
_________________ -lance
It's easier to fool people than to convince them that they have been fooled.
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 11:51 |
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Joined: 05/17/10 Posts: 4007 Post Likes: +2029 Location: canuck
Aircraft: x23mouse
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not to worry Quote: In the near future, the diesel engine could be replaced with an electric or hydrogen one, to make the plane emissions-free. "
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 12:11 |
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Joined: 04/26/13 Posts: 21667 Post Likes: +22228 Location: Columbus , IN (KBAK)
Aircraft: 1968 Baron D55
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Username Protected wrote: It’s just a piston aircraft with massive turbocharging designed to fly at a bazillion feet which is ultra efficient. This is not magic. The problem is getting up there in a reasonable amount of time, which they haven’t solved. <cough> JATO </cough> 
_________________ My last name rhymes with 'geese'.
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 12:36 |
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Joined: 08/05/16 Posts: 3137 Post Likes: +2283 Company: Tack Mobile Location: KBJC
Aircraft: C441
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Username Protected wrote: It’s just a piston aircraft with massive turbocharging designed to fly at a bazillion feet which is ultra efficient. This is not magic. The problem is getting up there in a reasonable amount of time, which they haven’t solved. What they seemed to have solved really well is making it look super goofy and combining that with misleading claims which results in a very high click through rate for online publications.
This is to say nothing of deicing, ultra reliable pressurization system at those dangerous altitudes, and reliably maintaining laminar flow. Well, the P180 has shown that you can achieve great savings if you design in a fashion that prioritizes laminar flow and drag reduction. Add diesel engines to this and the savings go up. It's not inconceivable that it could achieve 15% of bizjet operating cost, but with less performance.
Look at the climb rate and do the math, it’s not a real airplane. The Piaggio is.
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 13:13 |
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Joined: 11/30/17 Posts: 1380 Post Likes: +1584 Location: KARR
Aircraft: J3, Twin Commander
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Username Protected wrote: interesting article I hope they can make it work reliably..
Laminar flow is notorisly hard to make happen reliably.
dealing with ice could be an interesting problem. perhaps heated wings. Gliders have wipers that run the length of the wings to remove bugs as they disrupt the laminar flow.
[youtube]https://youtu.be/lpDUatAb0Sk[/youtube]
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 14:44 |
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Joined: 01/23/13 Posts: 9132 Post Likes: +6887 Company: Kokotele Guitar Works Location: Albany, NY
Aircraft: C-182RG, C-172, PA28
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Username Protected wrote: Gliders have wipers that run the length of the wings to remove bugs as they disrupt the laminar flow.
[youtube]https://youtu.be/lpDUatAb0Sk[/youtube]
I wonder if the gain from wiping the bugs off is that much more than the penalty you pay from the drag at the root when they're stowed, the drag when they're in operation, and the weight.
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 15:21 |
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Joined: 02/27/19 Posts: 529 Post Likes: +261 Company: OwnShip Technology AG Location: Zurich, Switzerland
Aircraft: C33/P32R
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Username Protected wrote: I wonder if the gain from wiping the bugs off is that much more than the penalty you pay from the drag at the root when they're stowed, the drag when they're in operation, and the weight.
Since gliding is a pretty competitive sport, my uneducated guess would be yes 
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 15:54 |
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Joined: 05/17/10 Posts: 4007 Post Likes: +2029 Location: canuck
Aircraft: x23mouse
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William Otto Sr https://www.ottoaviation.com/about-usOtto Aviation CEO (Bill Otto Jr)Talks Avionics, Connectivity Suppliers for Celera 500L http://interactive.aviationtoday.com/av ... lera-500l/https://www.forbes.com/sites/erictegler ... 6c555fbccaQuote: As for the A03’s ability to offer enough power to get Celera to its 450-mph cruise speed at altitude Slater says, “Making 500 horsepower at 40,000 feet would take an insane amount of turbocharging, turbo pressure. It’s not something I’ve seen before outside of tractor-pulling engines which can have up to 200 pounds of boost at sea level.”
But the A03 won’t make a full 500 horsepower at altitude. Even with multiple turbos Slater notes that RED only claims the ability to make 500 hp at 25,000 feet, not at 40,000 feet. He points out that the limitation is not unique. A turboprop engine like the ubiquitous Pratt & Whitney PT-6, which has a 750 to 850 maximum shaft horsepower rating at sea level produces less than 300 hp at 28,000 feet.
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 16:58 |
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Joined: 08/24/13 Posts: 9708 Post Likes: +4535 Company: Aviation Tools / CCX Location: KSMQ New Jersey
Aircraft: TBM700C2
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Username Protected wrote: Quote: A turboprop engine like the ubiquitous Pratt & Whitney PT-6, which has a 750 to 850 maximum shaft horsepower rating at sea level produces less than 300 hp at 28,000 feet. I'll have to tell my torque and power gauge it is lying to me
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 17:49 |
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Joined: 01/28/13 Posts: 6206 Post Likes: +4236 Location: Indiana
Aircraft: C195, D17S, M20TN
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Username Protected wrote: Quote: A turboprop engine like the ubiquitous Pratt & Whitney PT-6, which has a 750 to 850 maximum shaft horsepower rating at sea level produces less than 300 hp at 28,000 feet. I'll have to tell my torque and power gauge it is lying to me[/quote] Best post of the day Terry. Poet in the making…. 
_________________ Chuck KEVV
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 18:12 |
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Joined: 01/18/11 Posts: 7664 Post Likes: +3696 Location: Lakeland , Ga
Aircraft: H35, T-41B, Aircoupe
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SHP =(Prop RPM x Torque ft-lbs)/5252
PT6A-42 850 SHP 2230 ft-lbs @ 10k feet = 764 SHP 2132 ft-lbs @ 16k feet 1952 ft-lbs @ 20k feet 1733 ft-lbs @ 24k feet 1610 ft-lbs @ 26k feet 1484 ft-lbs @ 28k feetk 1304 ft-lbs @ 31k feet 1186 ft-lbs @ 33k fe
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 06 Nov 2021, 18:53 |
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Joined: 08/26/15 Posts: 9930 Post Likes: +9831 Company: airlines (*CRJ,A320) Location: Florida panhandle
Aircraft: Travel Air,T-6B,etc*
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That 750-850hp sea level rating PT6 sounds like it is in reference to the thermodynamic limit of one of the small core engines, not the flat rating.
That's a bit of strange comparison, since flat rated turbines and turbocharged pistons both have a characteristic critical altitude. Thermodynamic limit is mostly a nifty advertising thing that tells you a theoretical number that the engine could make if the gearbox was infinitely strong; I don't think I've ever heard the term used for turbocharged piston airplanes. I can see where the logic is headed though, because Celera's engine is a lot like a grossly overboosted tractor pull engine (mentioned in an earlier paragraph) that has been greatly de-rated for sea level.
That 200psi boosted tractor pull engine isn't a bad comparison. If you had that kind of plumbing on an engine but you flat rated as a turbo-normalized engine, its critical altitude would end up between 50,000-60,000 feet.
Forbes did alright summarizing some engineering concepts, really above average work for a non-technical periodical, but the article is a little vague in showing the work behind the numbers they're tossing out.
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Post subject: Re: Otto Aviation Celera 500L Flew This Week Posted: 08 Nov 2021, 19:09 |
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Joined: 08/26/15 Posts: 9930 Post Likes: +9831 Company: airlines (*CRJ,A320) Location: Florida panhandle
Aircraft: Travel Air,T-6B,etc*
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Username Protected wrote: Here's a PT6 PT6A-67, that's just about the biggest kind they make, at least the turboprop versions. Big difference between the A-67/A-68 and A-25 versions. By the way, that is a fine airplane that that engine is pulling along! 
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