Random Aerodynamic Oddity of the Day Thread

[kach22i]

February 16, 2021
The Design of the Celera 500L
https://www.flyingmag.com/story/airc...a-500l-design/

The Celera’s fuselage shape is intended to achieve as much laminar flow as possible.Courtesy Otto Aviation

This oddity has now made its formal debut.

The principal claim made for the Celera is that it supports an unusual amount of laminar flow and therefore has unprecedentedly low drag.

[redneck]

Originally Posted by kach22i

February 16, 2021
The Design of the Celera 500L
https://www.flyingmag.com/story/airc...a-500l-design/

Excellent post...

Full information can be found here:

https://www.ottoaviation.com/celera-500l

RED A03 Engine Specifications

Liquid cooled V12, twin 6-cylinder bank, capable of independent operation with mutually independent critical engine sub-systems for each bank
Type certification approval granted via EASA (TC.E.150) and FAA (E00092EN)
Certified to operate on readily available Jet A1 and biodiesel
Capable of 550+ takeoff horsepower and best-in-class fuel efficiency
Controlled via fully redundant electronic engine control unit with single power control lever reducing pilot workload
Lightweight, all-aluminum design

Gliding Capability

The Celera 500L has a glide ratio of 22:1 (typical GA aircraft of similar size have a glide ratio of < 9:1). At an altitude of 30,000ft The Celera 500L can glide up to 125 miles with no engine power. This is roughly 3x better than the typical aircraft.

Super cool 😎...

Thanks for posting...


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[cRiPpLe_rOoStEr]

That engine seems quite complex, but it's still an interesting design. On a sidenote, since the U.S. seized blueprints of DKW motorcycles as part of the war reparations, it does surprise me how aeronautical Diesel engine designs from companies such as Junkers fell out of favor within the U.S. aircraft industry by then.

[Bicycle Bob]

Originally Posted by cRiPpLe_rOoStEr

That engine seems quite complex, but it's still an interesting design. On a sidenote, since the U.S. seized blueprints of DKW motorcycles as part of the war reparations, it does surprise me how aeronautical Diesel engine designs from companies such as Junkers fell out of favor within the U.S. aircraft industry by then.

No turbocharger is mentioned, even for high-altitude work. The Napier Nomad gave the best mileage in the 50s, and was more like a turbo jet with the peak temperatures moderated by using pistons for the initial expansion.
Cylinders that are not in use still create friction with this setup. I don't think anybody liked that 4-6-8 Cadillac option.

[samwichse]

Originally Posted by Bicycle Bob

No turbocharger is mentioned, even for high-altitude work. The Napier Nomad gave the best mileage in the 50s, and was more like a turbo jet with the peak temperatures moderated by using pistons for the initial expansion.
Cylinders that are not in use still create friction with this setup. I don't think anybody liked that 4-6-8 Cadillac option.

Not in that article, but it is there.

https://www.boldmethod.com/blog/list...tionary-plane/

Piston-Powered RED A03 V12 Engine
The A03 has a multi-stage turbocharger and can run on Jet-A fuel, kerosene, or biodiesel. It's an extremely high-efficiency design with low fuel consumption and increased reliability over existing piston engines.

[freebeard]

Originally Posted by CR

That engine seems quite complex, but it's still an interesting design

Two redundant banks on a common crankshaft. If I understand correctly, it's to get twin engine reliability. This suggests the crankshaft is the most reliable part.

[cRiPpLe_rOoStEr]

Originally Posted by Bicycle Bob

Cylinders that are not in use still create friction with this setup. I don't think anybody liked that 4-6-8 Cadillac option.

This is meant to increase redundancy as a safety measure, not as a fuel-saving attempt.

[freebeard]

This is an aerodynamic oddity so I'll drop it here.

I've mentioned a few time that R. B. Fuller advocated for indoor windmills. I've always liked the idea. Here's someone who gets it.


www.euronews.com/living/2020/09/30/could-this-be-the-safest-most-powerful-wind-turbine-in-the-world

It's not clear about their hubless rotor design but the converging duct is the key. This needs to be embedded at the zenith of a sizable hemisphere. Then the guide vanes can be extended to increase that 40% factor. Putting it on top of the hemisphere increases the nominal wind speed even more.

It appears to be a 1kW device. There is a Kickstarter page, but it doesn't like Raspian's system clock.
_________________

Maybe more on-topic, I found thing looking for something else:



historysdumpster.blogspot.com/2016/05/1930s-traveling-movie-theater.html

[Bicycle Bob]

Originally Posted by freebeard

This is an aerodynamic oddity so I'll drop it here.

I've mentioned a few time that R. B. Fuller advocated for indoor windmills. I've always liked the idea. Here's someone who gets it.


www.euronews.com/living/2020/09/30/could-this-be-the-safest-most-powerful-wind-turbine-in-the-world

It's not clear about their hubless rotor design but the converging duct is the key. This needs to be embedded at the zenith of a sizable hemisphere. Then the guide vanes can be extended to increase that 40% factor. Putting it on top of the hemisphere increases the nominal wind speed even more.

It appears to be a 1kW device. There is a Kickstarter page, but it doesn't like Raspian's system clock.

Yet, every single analysis shows that unless you are dealing with limited space or other exotic conditions, you always get more bang for the buck by taking material from the ducting and adding it to the turbine.
That said, if I were buying wind turbines, I'd save time and money by using guy wires on the tower below the turbine blades, and add a fairing to the upper tower that turns with the power head. The blades would probably also benefit from short guy wires. Anyone who has put up a dodgy shelf should be able to appreciate the potential savings.

[freebeard]

I'd save time and money by using guy wires on the tower below the turbine blades, and add a fairing to the upper tower that turns with the power head.

What does the tower do? It gets you above the microclimate. What does the hemisphere do? It draws air movement down into the microclimate.

Fuller's Dymaxion House had a rotating fairing, but it only exhausted interior air.


socalarchhistory.blogspot.com/2011/12/structural-similarities-in-work-of.html

The blades would probably also benefit from short guy wires. Anyone who has put up a dodgy shelf should be able to appreciate the potential savings.

Not getting that at all. The rotor is wired like a bicycle wheel?