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Old 09-09-2020, 03:33 PM   #11 (permalink)
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cross-sectional area

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Originally Posted by kach22i View Post
I'm perplexed by the increase the cross-sectional area compared to the typical pencil shaped body.

Every time I draw a hump over a vehicle cabin that is higher than needed for headroom it gets shot down.
It's the whole 'laminar' trick.
The boundary layer will remain laminar as long as pressure is lower in the flow direction.
Once the first ( only) minimum pressure ( maximum local velocity ) is encountered, after that, in the lee of the maximum cross-section the pressure increases as the cross-section contracts, and the laminar boundary layer 'jumps' to turbulent boundary layer, with terrific, comparative viscous shearing losses.
For us, typically submerged in Earth's own turbulent boundary layer, we can never have a laminar boundary layer, on account of Reynolds number effects. At 41,000-feet it's different.

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Old 09-09-2020, 03:41 PM   #12 (permalink)
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Every time I draw a hump over a vehicle cabin that is higher than needed for headroom it gets shot down.
People just ignore me.
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Old 09-11-2020, 01:12 AM   #13 (permalink)
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The powerplant makes the plane. The diesels have 10~15% better BSFC than a gasoline engine. The turbines don't come close.
I was all in for the zoche radials that never quite happened.
https://en.wikipedia.org/wiki/Zoche_...rs%20per%20row.
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Old 09-11-2020, 03:06 AM   #14 (permalink)
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I made the same point in Permalink #3.

I am a fan of the en.wikipedia.org/wiki/Split_cycle_engine. I couldn't remember the name Scuderi but the general article shows there is more history. I still think a boxer four would be the best configuration. Gas/compressed air hybrid.

It appears though, that the up 'n comer is the Achates opposed piston engine. Based on the Junkers_Jumo_205 but with modern materials and fuel injection. The current shipping product is a standby diesel generator.
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Fairbanks Morse Engine in the 1990s merged with ALCO to make the FMALCO line. In October 2013, FME signed a joint development and licensing agreement with Achates Power to reduce emissions and fuel consumption of Fairbanks Morse proprietary and dual-fuel opposed-piston engines.[18] The opposed-piston diesel engine once made by Fairbanks-Morse is still (August 2019) manufactured as well as the new Trident OP for electric power generation.
en.wikipedia.org/wiki/Fairbanks-Morse#Modern_descendants
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Old 09-11-2020, 10:21 PM   #15 (permalink)
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https://www.machinedesign.com/archiv...lanes-are-here

The 42mpg airplane has been hyped up for what ?
Over a decade, I think it’s more an issue of willpower, getting a tdi approvedfor the air is likely a pain as well
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Old 09-11-2020, 11:15 PM   #16 (permalink)
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It looks great. If I were in that tax bracket, I'd be in.
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Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

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Old 09-12-2020, 12:19 AM   #17 (permalink)
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Originally Posted by rmay635703 View Post
https://www.machinedesign.com/archiv...lanes-are-here

The 42mpg airplane has been hyped up for what ?
Over a decade, I think it’s more an issue of willpower, getting a tdi approvedfor the air is likely a pain as well
the 310 would get a solid 11 MPG at 21 squared, but you'd get 13 or so if you feathered one and ran the other at 2300 RPM or so. I never went that route
I would daydream about a pair of those zoche 300 HP diesel radials. The ones that never got out of testing :facepalm:

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