Otto Aviation Celera 500L

[drawoh]

This is being written up on Engineering.com.

Otto Aviation Unveils New Celera 500L Aircraft with 40% Lower Carbon Emissions

I have seen some YouTube videos as well, as well as Otto Aviation's website. Apparently, this thing "has a fuel economy of 18 to 25 miles per gallon while having an impressive cruise speed of 450 miles per hour and a range of 4,500 miles". The engine is a six litre, 500HP diesel V12. There are no specifications of size and weight anywhere. The aircraft can hold six passengers, and there is room in the cabin for a six foot person to stand upright.

Does any of this sound believable? A P[‑]51 Mustang, with laminar flow wings, has a maximum speed of 440mph on around 1500HP. These speeds are approaching the capabilities of propeller driven aircraft. Mustangs are exceptionally efficient. Other 450mph aircraft, like Spitfires, Thunderbolts, Corsairs, and Hornets, use over 2000HP.

--
JHG

 

[3DDave]

There must be some advantage to being a pusher; tough to maintain laminar flow over a fuselage with a tractor prop; also if it is pressurized and they are looking at performance at 30,000 feet, then perhaps that helps.

OTOH - there are an enormous offsetting number of aircraft announcements that are usually composted to fertilizer that sound just as promising as this does. Moller, Moller, is Moller here? The lack of simple span, L/D, or other typical aerodynamic facts that are usually released increase the odoriferous level.

 

[GregLocock]

500 hp, say 350 kW. Likely mass is of the order of 1500kg empty, call it 2500 kg laden, so L/D=350000/(2500*10*200)=14 so not ridiculous. However 4500 miles at 4 mpg is 1080 gallons of fuel.

So rework the above

3500000/(6500*10*200)=37. The average of 14 and 37 is 26, which is getting up there towards glider territory, and almost exactly the same as U-2

Mr Breguet needs to get involved, to refine that number.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[drawoh]

GregLocock,

I cannot find a weight specification anywhere for that thing. 1500kg is a Piper Aztec, with a never-exceed speed of 277mph. The Cessna Citation Mustang is described as a "very light jet". It has performance fairly equivalent to the Celera 500L, it's pressurized, and it's 4000kg.

Sticking with the Cessna...

Power = Force [×] Velocity = 2[×]6500N [×] 630km/hr [×] 1000m/km [×] 1/3600hr/s = 2.3[×]10[sup]6[/sup]N.m/s (or W).

2.3[×]10[sup]6[/sup]N.m/s [×] 1/4.45lb/N [×] 1/.3048ft/m 1/550HP.s/ft.lb = 3000HP.

Maybe maximum thrust is used only for take-off. Those long, thin wings on the 500L look efficient, but the fuselage holds seven more people than the P[‑]51's does. There has to be more frontal area. Laminar flow only accomplishes so much, especially when Brand[ ]X uses the technology too.

--
JHG

 

[rb1957]

like all things in design, there are advantages and disadvantages with everything.

pusher prop … better airflow over the fuselage (and/or wing) but disturbed airflow over prop (remember Boeing's prop-fan of the 90s ? (one thing) they couldn't solve was the airflow over the prop.

There are other prop planes out there (Piaggio P180) … so it's not insolvable. Avanti also has a very smooth OML … fuselage panels are tooled into position and the frames placed to suit. So we can figure fuel consumption with a typical PT6 turbo-prop, then we can figure the improvement a diesel adds ?

The size of the fuselage is awful (for maximising aero performance … another design trade-off.

If this relies on laminar flow wings, be careful … laminar flow works well when it works, but is awfully sensitive to imperfections (remember the ATR42/72).

another day in paradise, or is paradise one day closer ?

 

[drawoh]

rb1957,

I forgot about the Piaggio[ ]P.180. It takes seven to nine passengers, so it is somewhat bigger. Empty[ ]mass[ ]4000kg. 460mph[ ]max. 370mph[ ]cruise. 2[×]850HP[ ]turboprops. Modern, highly aerodynamic design and composite structure. Fuel[ ]0.779lb/mile.

Gasoline is about 6.3lb/gallon, so...

1 [÷] .779lb/mile [×] 6.3lb/gallon = 8mpg.

That actually is not bad. My uncle and aunt had a Pontiac of some sort with a 454ci V8 that did 8mpg, and it was not cruising at 370mph.

--
JHG

 

[verymadmac]

The current test airframe doesn't appear to have passenger windows or any of the normal external antennas that I can see (apparently its mostly metal as well), how representative it i

https://www.eng-tips.com/postedit.cfm?id=8603099&action=edits

of a production airframe is an interesting question in its self. Although ditching the windows and replacing with digital windows would be pretty appealing (weight, maintenance cost, cabin configuration etc).


How long will it take to get to 30,000 or 40,000 ft, the Avanti starts at 3000 ft/min @S.L, the Otto looks more like 1000 ft /min @ S.L(any one think the GW would be under 10,000 lb) oops should have checked the source data, gross looks more like 4000 to 6000 lb. Sea level climb rate is more like 1700 ft/min. The other question is if its so clean, how do they add the extra drag to get a proper descent rate (one that's not to upset air traffic control).

Out of interest the Avanti specs are here

http://www.smartcockpit.com/docs/P180_Avanti-Specification_and_Description.pdf

 

[rb1957]

so this thing, compared to the Avanti, has 30% the installed power, claims 1/2 (to 1/3) the fuel consumption. More efficient design will get you some of that … but Avanti is a pretty efficient shape. A diesel could be more efficient but you'd've thought heavier. The dream may be intercity flights as cheap as commercial flights … but
1) demand ?
2) network ?
3) off design performance (contaminated stalls ?), icing, …

yeah, but we're all a bunch of "negative nellies" …

another day in paradise, or is paradise one day closer ?

 

[Sparweb]

Does Otto Aviation have Jan Roskam working on the design? It seems to have his fingerprints on it (JR did the prelimiary design of the Avanti).

http://www.sparweb.ca

 

[WKTaylor]

IF Celera 500...: can be fitted for high quality passenger accommodations/comfort; and if 'design/mission creep' [weight/drag/parasite EE/hydraulic-power, etc] are kept in-bounds; and if crew visibility is adequate with the current window arrangement... without video-camera enhancement; and if crash worthiness/survivability/escape is adequate; and if the single diesel engine is producible-maintainable-reliable; and if there are exterior color selections available... other than snow white; and if exterior lighting can be enhanced; and if the flight control... and other systems [mech, EE-EL-AE, etc]... are robust and durable; and if it has been tested/vetted for a wide range of speed-loads-CG-flutter-etc; and if the structure/systems are tough/durable [fatigue and limit/ultimate loading, free of flutter, etc]... Then it could be a smash-hit with customers and the FAA alike.

It would be interesting to track the flight history of 'N*18WM' on one of the flight-watch/flight-following websites over the last several years... for 'hard-stare' at real speed-range-altitude validation testing.

As was stated on another website... extraordinary claims demand extraordinary proof.

Unfortunately extraordinary configuration aircraft... incorporating many novel aspects at one time... tend to draw peculiar/intense attention/scrutiny from certification agencies… especially intense after 737-MAX.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[Sparweb]

extraordinary claims demand extraordinary proof

I didn't know Marcello Truzzi had a website! But he wrote many books.

Everyone, get some perspective. Nothing being discussed here is as ridiculous radical as the Eviation Alice!

I am so disappointed that the Alice battery fire denied the world's aviation community of the dramatic spectacle of a simultaneous cross-wind wingtip-strike, prop disintegration and ground loop.

http://www.sparweb.ca

 

[WKTaylor]

SparWeb… sorry slight miss-quote on my part... DANG.

Extraordinary Claims Require Extraordinary Evidence.” –Carl Sagan, Astrophysicist

The elementary rules of logic... that extraordinary claims require extraordinary evidence and that what can be asserted without evidence can also be dismissed without evidence.” --Christopher Hitchens


Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[drawoh]

SparWeb,

I posted on the Eviation Alice (thread16-431720), for pretty much the same reason. Are the wingtips really the best place to put motors? Even the article on Engineering.com is sceptical. The photograph in the Wikipedia article is more believable.

--
JHG

 

[Sparweb]

Somehow the Alice evolved from having a tricycle gear to a prototype with tail-dragger landing gear. So these days with few examples of such an arrangement, the likelihood of an unfamiliar pilot doing a ground loop is very high. Combine that with the engines on the wingtips - the chaos that would inevitably result...

In the rush and excitement to make a marketable EV aircraft, basic aviation is being forgotten. These creative designs are eye-catching, but they also speak to a market that wants to buy because it's new and broadcasts a message, especially when parked in the hangar, not so much because it's a good quality aircraft.

If I were a private pilot, or for example a flight training company, and was offered an EV aircraft that operates for 1/2 the hourly costs of an equivalent fueled aircraft, even if for somewhat less range, I would seriously consider it. My tolerance for a reduced EV envelope will stretch a bit, and the other guy beside me might have less or maybe more tolerance. Either way, a drastic drop in operating costs would help many pilots get over their reluctance. If somebody could just get over the gap.

I think the Skymaster hybrid conversion is a good step in the right direction. Uses a tried-and-true aircraft as a development platform. They can learn what they need to learn about the practical matters of operating an EV aircraft for a few years, doing it in an airframe with no surprises.

http://www.sparweb.ca

 

[WKTaylor]

SW... RE power at wing tips...

The asymmetry with main propulsion [props, driven by EE-motors or fuel-engines] at the wing-tips would be ridiculous… every multi-engine pilot would understand this massive asymmetry... small power differences adding large yaw-torque effects... that would be made much worse with propulsor failure... and a prop that also failed to 'feather'.

HOWEVER... IF the main propulsion [props] delivering ~90% [45% X2 or 22.5% X4] thrust was located inboard at more-conventional thrust locations [pusher~]… with ~10% [5% X2] props at the wing-tips for affecting the wing-tip vortices... that might be a useful/beneficial division of thrust.

NOTE.
I was an O-2A/B engineer for ~3-years and became familiar with the entire bird... that configuration has lots of aero inefficiencies... but is 'sweet' for pilots to fly safely... especially the O-2TT turbine demonstrator with gross excess power.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[Sparweb]

... turbine demonstrator with gross excess power.

As a former mentor of mine often said "with engine power, lots is good, more is better, and too much is just enough!"
He built and flew a Pitts Special.


Today, nobody is proposing or even imagining an electric Pitts. Which is a shame - it's almost the right target. A Pitts isn't meant for long journeys. It's entire purpose is to go up, show off, pull off a close call, and then land to change your pants. An oversized electric powerplant and an undersized battery pack would do just fine for that purpose.

http://www.sparweb.ca

 

[3DDave]

It's the right amount of power when one can do a snap roll, hammerhead stall, another snap roll, and then nail the landing, and the guy at the gas pump admires the way you handle a tail dragger while still on the apron.

 

[jaceb]

Hi Folks,

I did study for one of customers for the diesel proppulsion than i can share some conclusions. Well known turbine engine was used as benchmark
- propulsion system weight - twin turbo diesel with comparable power level will be roughly 200-250% heavier than turbine
- take off fuel consumptiom - diesel is wining with 30% margin
- cruise fuel consumption - here is real gain - almost 50-60% for the diesel - but this is based on catalog data, with assuming bigger needs for cooling system and drag related to it's general size we still have nice 30-45% advantege over turbine
- ownership cost - diesels in certification process looks very promising here - most of them is requesting no scheduled maintenance intervals (yeah - guys in marketing departments believe in this - but always will be at least some on life limited parts) and on condition maintenance philospophy
Some words about pusher configuration - i'm digging it out of memory - NACA's data related to US pusher fighter configuration projects (Ascander, Black Bullet projects) have indicated general efficiency gain for pusher in range of 4% - well, problem was that test flights of the mentioned fighters never confirmed such claims - what was confirmed - problematic installation of the engine (large scoops on Celera - 8/10 airplane designs with such powerplant location have ended with difficult to solve issues with powerplant cooling), problems with effectiveness of horizontal and vertical stabilisers and it's control surfaces . Word about Piaggio - from personal experience - is freaking noisy compared to similar airplanes with tractor propellers . One more comment - diesel engine availability - by search i did 500HP aircraft diesel available on market is as many as 1 (one) - in development stage. Most of us are perfectly comfortable with situation when we are working on airplane in engine in development stage - it never failed isn't it?

 

[verymadmac]

The engine (RED A03) does have a TCDS, so a reasonably final design

https://www.easa.europa.eu/sites/default/files/dfu/EASA_E_150_TCDS_REDA03_issue 02_20180827.pdf

 

[rb1957]

when you say "30% margin", I read that as 2/3rds, so a 50% improvement in fuel consumption … much less than the claimed 800% !? (but since when did a new design's early claims prove "optimistic" ?

with the limited supply of aero diesel engines, albeit certified already, I wonder what the price/volumes are like (compared with conventional engines).

"no maintenance" … yeah, right !

another day in paradise, or is paradise one day closer ?