🚀 go-pugleaf

Craig Meyer writes:
Hi, folks.  I'm the one that wrote about a lift system using driven air and a
stationary wing.  I've gotten some responses, but I want to make sure you all
know what I'm talking about.  So here goes:

Below is a super-sorry rendition of a airfoil, with an duct coming out of the
upper leading-edge.  High-speed air (from some central centrifugal blower or
something) shoots out of this duct, and over the wing.

Lift is produced by the resulting static-pressure difference between the top of
the wing (with the driven air flowing over it) and the bottom of the wing,
where the air is still.

Thrust is produced, too, becuase the air is being blown BACK, (action-reaction,
ya know).

Once you got going, you could retract the duct into the leading edge of the
wing, and blow the air out some ducts in the very back, for thrust only (since
you'll be getting lift naturally becuase you're moving)


             ------      LOW PRESSURE
           /   <- air comes out here   Flows out t

 leading /      ------------------------------\    h
  edge /                     / \                 \   i
       \                      |        ------>      \   s
         \                    |lift    thrust          \  w
           \--------------------------------------------- \  a
                        HIGH PRESSURE                          y
 
So that's it.

Please tell me whatever you think about it (if I'm a genius, an idiot, a
plagariser, whatever..)

Thanks all,

End, Craig Meyers





Your leading edge blowing concept has been around (I actually
wnated to do my MS research on leading edge blowing with a
circulation control trailing edge, had to settle for unsteady
circulation control instead :-)).  Anyhoot, there is not to
many jets available that would provide all the lift you want in 
the manner you describe.  Currently, folks in my branch are looking
into leading edge blowing, but only for vortex control not for
providing all the lift.

Just as an aside, you'll get more lift out of a circulation control
trailing edge than leading edge blowing (but you will still need
some freestream flow).  If you ever want references on circulation
control, let me know and I'll give you some good'uns.  I might also
still have some references on leading edge blowing, I'd have to look.
Hope this helps.

T.A. Ghee

01crmeyer@leo.bsuvc.bsu.edu (Craig Meyer) writes:
>Lift is produced by the resulting static-pressure difference between the top of
>the wing (with the driven air flowing over it) and the bottom of the wing,
>where the air is still.

>Thrust is produced, too, becuase the air is being blown BACK, (action-reaction,
>ya know).

>Once you got going, you could retract the duct into the leading edge of the
>wing, and blow the air out some ducts in the very back, for thrust only (since
>you'll be getting lift naturally becuase you're moving)

>Please tell me whatever you think about it (if I'm a genius, an idiot, a
>plagariser, whatever..)

This concept was tried on the Ball Brothers JetWing about 20 years ago
as I recall. Ralph Kimberlin at the University of Tennesse Space
Institute flew it, and it was no joy to fly. The airplane was very
heavy due to the metal ducting to handle the hot exhaust gases 
distributed over the wings, and the handling characteristics varied
greatly, since the lift and pitching moment were thrust-dependent.
It was also interesting to land, since both lift and thrust were
lost simultaneously when power was reduced. There is a reason why
the sky is not filled with airplanes blowing hot air over the wings.

 

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|      Dept. of Aerospace Eng.        |   you never have to fix anything |
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In article <1992Dec16.194714.13105@bsu-ucs> 01crmeyer@leo.bsuvc.bsu.edu (Craig Meyer) writes:
>
>
>             ------      LOW PRESSURE
>           /   <- air comes out here   Flows out t
> leading /      ------------------------------\    h
>  edge /                     / \                 \   i
>       \                      |        ------>      \   s
>         \                    |lift    thrust          \  w
>           \--------------------------------------------- \  a
>                        HIGH PRESSURE                          y
> 

This reminds me of the flap-blowing in the Lockheed F-104 Starfighter
and the scheme used by the DHC Buffalo converted by NASA into the
QSTOL aircraft.
	In the F104, which has very short wingspan (22 feet?) and high
wing loading (25000 lbs weight ?) they took bleed air from the jet
engine and blew it back over the flaps to keep the airflow attached at
high angles of attack. I hear the problem was the engine had to be at
80% RPM or more to keep landing speeds reasonable, and that the
scariest thing to practise was deadstick landings in an F104. No
engine, no BLC, and approach speeds were probably 190 KIAS + with the
nose pitched up so high the runway couldnt be seen on final (sort of
like a Pitts).
	In the NASA QSTOL, the engines are on top of the wing, and the
jet exhaust blows back over the top of the wings and flaps. The high
energy air stays attached even at very low aircraft IAS and this 50000
lb jet aircraft has operated off aircraft carriers with no problems
(no catapults or tailhooks needed).

So I guess your idea works.

Gopal
-- 

Gopal Ramachandran <gopal@cirrus.com>
UUCP:  uunet!cirrus.com!gopal
Cirrus Logic Inc, Fremont CA  PH: (510)-226-2138 FAX: (510)-226-2160