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

 

[Sparweb]

Today, nobody is proposing or even imagining an electric Pitts

A slight correction is deserved. Extra tried it. The modified 330 managed a >1,000 FPM climb.

Of course... a Pitts or a Skybolt will climb > 2,000 FPM. Much more...

http://www.sparweb.ca

 

[drawoh]

jaceb,

I have just been reading up on the Ju[ ]86. During the 1930s, the German experimented with diesel engines for aircraft. Many Ju[ ]86s were powered by Junkers Jumo[ ]205s, which were two[‑]stroke diesels.

I am not an engine guy. I assume that the two[‑]stroke cycle made the engines smaller and lighter? The concept did not catch on.

--
JHG

 

[WKTaylor]

drawoh…

Diesel fuel has always been far more plentiful that refined aviation gasoline... it time of war FUEL AVAILABILITY makes a huge difference.

During the Vietnam war... the following fuels had to me supplied 'in-country'...

MO-gas [auto gasoline]... for small vehicles [Jeeps, Mules, cars, PU trucks, light generators, etc

Diesel... APCs, Tanks... etc... and Heavy trucks, heavy-duty generators, etc,

Bunker Oil.. for heavy warships

80--87 and/or 90-97 octane Avgas for small piston engine Acft [O-1, O-2, etc]

100-130 octane avgas for A-1, A-26, S-2, etc... heavy radial engine Acft... and muddy water patrol boats [using aircraft piston engines] etc...

JP-4 USAF and US Army and early USN/USMC

JP-5 for USN/USMC carrier-based

Jet-A for commercial aircraft

At the beginning of GWI and GWII...

Gasoline, Diesel and JP-4/JP-5/Jet-A and bunker-oil had to delivered in country... plus a few others...

In the Middle of GWII...

The USA, USAF, USN/USMC joined forces to supply 'turbine powered Acft... and multi-fuel vehicles [Diesel, JP5/JP-8, etc] and generators in battlefield... OH yeah and bunker fuel is always needed.

NOW at the end of GWII... Jet-A+ turbine fuel [with military additives] is being used in MOST Acft, ground vehicles and generators… all services... simplifying logistics TREMENDOUSLY. I heard that even UAVs must now be capable of using Jet-A+... gasoline powered UAVs are often grounded for lack of gasoline... unless bought at a local gas-station!

A by-product of using Jet-A is a significant improvement for all vehicles, IE: lower overall fuel cost, increased availability and fire/explosion safety [many aspects].

NOTE. I wonder if the Diesel in the Celera 500 is capable of running effectively on Jet-A???

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]

 

[3DDave]

Jet-A was good enough to run it in the HWWMV and a required alternate for the engine in aviation ground support vehicles the AF uses now. The energy density of Jet-A is about 10% lower than Diesel. I assume that would translate to range.

 

[jaceb]

drawoh,

you are perfectly correct - diesel engines are nothing new in aviation, Germans not experimented with diesels but they have it in regular use on Ju86, Do18, Do26 - this kind of propulsion system is perfect for airplanes with power needs up to around 500kW, benefits are clearly visible for the long range/endurance airplanes, north of this line weight to power ratio becoming difficult to accept. Also important factor is that EU Commision is pressing for removing Avgas from use - i've already seen couple circulars which clearly indicationg that this process has been started.In relation to what have been mentioned by 3DDave - F-34 has been standarized as a aircraft/land vehicles fuel within NATO structures - all miltary turbines and diesels has been certified for use this one.

 

[jaceb]

i olmost forgot - not only Germans have been successfull with this kind of engines - Soviets Yer-2 and Pe-8 bombers have used M30 and M40 for stroke/V12 supercharged diesels.

 

[Lou Scannon]

Indeed, 2-stroke diesels led 4-strokes in power density until emissions regulations arrested their development... still, they are current in large low speed marine diesel engines, and some remaining non-emission-critical markets such as military.
The Jumo 205 had several salient features... opposed pistons, which economized on the number of cylinders for a given swept volume, at the cost of an extra crankshaft and gearing between the two cranks. Offset indexing of the cranks allowed tweaking of the port timing.



"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[jaceb]

Safran is working on 2 stroke boxer turbo diesel for aircraft application - mainly for drop in replacements in General Aviation field - it means we are back in point described by Hemi. Now i would like to put controversional questions - just because environmental factors has been called - by general public diesels are noticed inferrior to the gas engines (due to black smoke from exhaust during acceleration)- is it really true? with it's unmatchable fuel efficiency? - am i really more unfriendly for mother nature when my car is burning 1 US gallon /100km compared to "super efficient" hybrid powered SUV burning 3 gallons and my airplane will be burning less than 50% than turbine powered and 30% less than this one with gas engine? And yes - i'm fully backing idea that Diesel cycle engine is low hanging/ low technology risk level means to noticeably increase fuel economy level at least for the light transport/utility airplanes and light helicopters. Of course it is logic alternative untill battery powered electric propulsion will start rulling - but it is easy, all we need is just increase available power density of batteries 10-20 times and make it safe for use - piece of cake isn't it?

Polish proverb of the day:
Nobody can give you as much as i'm able to promise to you...

 

[Lou Scannon]

Certainly the more pernicious pollutants, NOx and particulates, are more difficult to bring to regulated levels in diesel engines compared with spark-ignited engines.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[jaceb]

Hemi,
Of course - but is anybody considered fact that burning 50% less fuel we can be 15% more off regulatory levels and we still will be far more environment friendly than "green" gas engine??? not mentioning that key word in your sentence is "difficult" which means it is not impossible. I'm sure that with proper shaping of cylinder cavity, sound design of the fuel injection system and engine control we may hit regulatory requirements without using all problematic compeonents sitting on the exhaust side.

 

[WKTaylor]

BTW... on the subject of diesel fuel use in [diesel powered] aircraft...

Is there an aviation diesel fuel standard like those for Turbine fuels????



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]

 

[rb1957]

an interesting link …

https://generalaviationnews.com/201...a rough-running or not running at all engine.

found by google "aviation diesel fuel specification"

from wiki "aviation diesel engines" ...
"Thielert, based in German Lichtenstein, Saxony was the original TC holder of the 1.7 based on the Mercedes A-class turbo diesel, running on diesel and jet A-1 fuel."

RED diesel says "runs on Jet A1".

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

 

[WKTaylor]

rb… RE Your linked article(s)... my head hurts.

So... NO aviation diesel-fuel standard for diesel-engines powering Acft.

This is troubling in that Jet-A 'works' in Diesel engines... but the consequences for use in Aircraft Diesel's are vague.

SO... I now presume that the Celera 500 Diesel engine must be 'purpose-built' to operate indefinitely/reliably solely on Jet-A... without additives... although it would likely 'work well' using Diesel 1 or 2 with controller adjustments??

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]

 

[verymadmac]

Just to clarify, when you guys say Jet A you mean just Jet A or is Jet A1 included in that for those of us who come from countries that only run Jet A1.

 

[Lou Scannon]

Of course - but is anybody considered fact that burning 50% less fuel...

Unfortunately, exhaust emissions don't work that way. To go further into this would be better done in its own thread. Not that I'm much inclined. Rather, if you're really interested in reciprocating engine emissions, diesel vs spark-ignited, there is plenty of information to be found online if you do some searching. You can also post your questions here on Eng-tips on the Engine & fuel forum.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[jaceb]

hahahaha - fuel issue has been widely tested by military personel acros the world - findings are:
1) Jet A1 /F34 is better than standard diesel in a term of much cleaner combustion (higher fuela manufacturing standard?), using Aviation grade fuel noticeably extending life of the injectors in diesels
2) Never run french made diesel engine on JetA1 only - reason is lubrication system of the engine accessories used in French made diesels (pumps are fuel lubricated so you need use fuel lubricating add ons for the two stroke engines) - engines with separate oil lubrication of the accessories run reliably on turbine fuel

this is practical knowledge not dressed in regulatory form of course.

 

[WKTaylor]

HomeBuiltAirplanes.com forum Jet-A VS Diesel [similar-to discussion]...

Jet-A vs. diesel …

https://www.homebuiltairplanes.com/forums/threads/jet-a-vs-diesel.34576/page-2#post-560443

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]

 

[RSalas]

Hello all,

Let me start, from drawoh initial statement. The Celera 500L cannot be compared with the P-51 from the aerodynamics and design point of view, they are worlds apart on that respect.
But nevertheless I want to show that the P-51D Mustang it’s not 440 mph on 1500 BHP!
As all of us know the Mustang had some big innovations in terms of aerodynamics (laminar airfoils, cooling with Meredith Effect, etc.)
NOTE: We have to be careful always how to compare performance data of different aircrafts, because this is always dependent of the model, weight, altitude, engine model, propeller, etc.!

P-51D

I choose version D, because it was the most mass produced one during WWII.
So from the beginning, the P-51D had a NACA five-digit airfoils (NACA 45-100), they here laminar flow airfoils to 55 to 60% of the chord (this data needs to be validated) but this really depends how the wing was in terms of dents, exposed rivets, bugs, dirt, bear in mind the P-51D was a combat aircraft ...
The P-51D it’s a tractor aircraft, this means any flight surface such as the wing, fuselage, vtp and htp are emerged in the propeller prop wash...means all the laminar flow.. it’s gone! The left overs for laminar flow it’s the outer portions of the wing, but and that regions has the gun ports, meaning only laminar flow on the remaining ~55 % of wingspan.

Now some aerodynamic & performance characteristics:

From wikipedia the following aerodynamic data can be derived, CD0=0.0163, drag area=0,355m^2 and a best L/D=14.6, it’s very good for a single engine tractor fighter aircraft, don´t get me wrong!
From Memo Report No. TSCEP5E-1908:

So at 30000 fts the engine it’s not producing anymore 1490 BHP, but 1180 BHP on War Emergency Power to achieve 439 MPH, this shows how efficient the aircraft was.

So some conclusions, the P-51D has a best glide ratio of 14,6 and a engine (Packard V-1650 Merlin) with a SFC of 0.50 lb/hp/h.

In the second part of my analysis I want to proof that the OTTO Celera 500L shows some credible performance data, and it’s nothing coming out of any eVTOL spinoff company’s BS that it’s very common nowadays.

Unfortunately OTTO Aviation don't provide too much data so I have assumed and estimated most part of the parameters based on my experience and bibliographic data. I would like in the near future to perform a more detailed analysis.

So what we know:

Best L/D = ~22 [1]
Range = 4500NM = 8334 km [1]
Engine = RED A03-003 [1]
Engine Power = +550hp (i.a.w source [5] the engine it’s certified to 500 hp Max TO Power 5 minutes, I will use this value for all performance evaluations).
Engine SFC = 0.35 lb/hp/h. not defined at a specific RPM or Power Setting [3]

END OF PART 1

 

[trincherengineers]

I read about it in the article, they mention that it has a glide ratio of 22 on their website. Doing a back of the envelope calculation and assuming an engine thermal efficiency of 45 percent, combined with a propulsive efficiency of 90 percent, I get a fuel efficiency of about 74 MPG for a one-tonne aircraft. That would translate into the stated figure if the weight is around 4 tonnes, so it doesn't seem impossible.
But still it sounds very good