elementcollector1
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Exotic Aircraft Wing Design - Peer Review?
(This isn't chemistry, but I feel it fits the 'mad science' theme enough, considering what I might end up using it for).
Ordinarily I'm skeptical of anything claiming too many benefits, but this research team appears to have published a series of papers without much
trouble on this subject:
http://highorder.berkeley.edu/proceedings/aiaa-appliedaero-2...
https://pdfs.semanticscholar.org/1fdf/8164eaa693beeb90fd2682...
The general idea seems to be that using a lower-power air pump to inject and suck air at certain points on the leading and trailing edge of a wing can
produce both lift and thrust, as well as reducing drag, all while drastically reducing or even eliminating the need for a conventional engine. As far
as I can tell, the idea seems valid and the simulations seem to back it up, but I'm not a mechanical/aerospace engineer. So, that said, can anyone
with a better background identify if this is a valid technology to look into?
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aga
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The geometry of the wing dictates exactly how it will perform in flight, all due to air pressure at certain points, so it sounds possible.
IIRC there was a ton of detailed research done which ended up as the 'NACA' list, which defines exact physical properties of many wing profiles.
That was found a few years back when a wing was required with a very low pitch moment.
Turned out to be NACA 23012 i think.
[Edited on 21-6-2018 by aga]
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elementcollector1
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Looks like they ended up choosing NACA 6425. Apparently, this was an unusually thick choice on their part due to the decreased potential for flow
separation allowing higher thickness aerofoils (and thus higher lift).
Still, I'm very unsure if this is legitimate or not. They mention that this was all done in a simulation (which, granted, seems to be quite an
extensive one), and has not been physically tested. They also mention that their test vehicle model, given its parameters, generated an
astonishing 542.8 kilograms of lift while traveling at a speed of Mach 0.1 (or 64 m/s).
From what little I know, lift is proportional to the square of the flow speed, which I'm assuming is equivalent to the aircraft velocity (just from a
different perspective). So I ran a quick calculation to determine how fast their test craft would have to be traveling to produce 130 kg of lift (this
being enough to lift any human person up to 290 pounds in weight). The answer came out to just 4.15 m/s, or 9.3 mph.
If I understand that correctly, if one could somehow strap said craft to their back, they could theoretically generate enough lift to fly themselves
by running. The design also apparently generates forward thrust, once again due to the peculiar air vortices surrounding the wing - this
makes me wonder if the thing would just keep accelerating when turned on until it hit 'terminal' forward velocity. That would fit the definition of an
'Engineless Aircraft' quite well... but something about all this still stinks of HHO to me. Surely it can't be this easy to produce so much
lift and thrust - otherwise one could strap a pair of wings, a battery and an air pump to their back!
EDIT: Here is the full list of results from their 3D computational fluid dynamics simulation:
Wing Span 2.4 m
Root Chord Length 1.16 m
AR 4.0
CFJ Area 1.24 m2
Airfoil thicness 25%
Cruise Mach 0.3
Cruise Altitude 20,000 ft
Weight 104.8 kg
Payload 100 kg
Take-Off Thrust 99.8 kg
Take-Off Lift 542.8 kg
Take-Off Velocity 64 m/s
Take-Off Distance 239.5 m
[Edited on 6/23/2018 by elementcollector1]
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