Hemi-Wing PAV Invention Idea

19-Mar-2009

Heretofore, all of these xxxx-PrjNotes.txt files were to save context for

small software projects. This one is for development of an invention, which

is (unfortunately) an "invention-in-the-large" sort of idea: a brand-new

approach to the PAV (personal air vehicle) concept.

I have made some rough sketches which might help illustrate what I mean.

Maybe I will scan them into this doc (after conversion to .rtf format or

something of that nature).

The idea is a hemispherical wing which creates lift by having air forced

over it (and under/through it) by a ducted fan. Think of a large umbrella,

squeezed into a more conical, curved shape, with a smooth straight cone

inside it, open at the top/apex, and having a ducted fan above it forcing

air down over the curved outer umbrella shape of the wing, and along the

straight smooth inner cone surface. This creates a circular/hemispherical

wing, with a 360° wing surface generating a torus of lift, directly around

and below the ducted fan.

This improves on the helicopter/gyrocopter PAV concept for several reasons:

+ It does not depend on pure rotor power for lift-- there is a wing

involved, so that there is more inherent efficiency and stability

than the helicopter.

+ Because the wing has air forced across it by fan, it is probable

that the wing would develop comparatively greater lift than other

wings-- The patented "fan wing" has air directly forced across the

wing surface and it has the highest lift per square unit surface

than any type of wing currently known.

+ When power is lost the hemisperical wing becomes the canopy of a

parachute-- not an ideally efficient parachute, but one which is

effectively a vast improvement over a helicopter with no power.

+ There is no "stall" with this hemi-wing... when lift dissipates,

air starts flowing in reverse over the wing and, as mentioned, it

begins to function as a parachute.

+ Steering is accomplished by manipulation of spoiler flaps on the

outer wing surface. This has potential for a more gentle and

forgiving control geometry than that of a helicopter.

+ Hemisperical wing shape has lots of wing surface in a compact,

circular footprint. It is possible that it would develop enough

lift for little enough power to render a very small, PAV-type

aircraft safe and economical.

The passenger/payload area is mounted below and "inside" the inner

straight cone part of the wing. The airframe geometry implies VTOL,

with landing being a matter of holding flaps in "hover" (neutral)

position, and feathering the fan throttle to set the craft down.

SO WHAT WOULD BE PLAN and STEPS:

--------------------------------

Prove concept with a working model, built with R/C helicopter parts.

The hemi-wing should develop more lift for less power than the unmodified

R/C heli of the same model as the one cannibalized to make the hemi-wing.

---- HOW do I test/measure and establish the truth of this?

BEFORE I get an R/C heli kit:

Build something simple (wing only)--light, spit-and-plastic-sheet-and-tape,

and see if you can get it to lift by holding a hair dryer on it as the

"ducted fan"...

READ UP/RESEARCH: ducted fans in aeronautical engineering.

IGNORE THE ULTIMATE ISSUE THAT

...this is really a high-barrier, high-cost-of-development-invention:

many outfits (e.g. airscooter.com) have spent $-millions attempting to

develop and sell a PAV. Even though this is a novel approach, original

enough to patent, success will require "big angel" investment, and

lots of venture capital style "concept marketing", and probably years

of full-time development.

One idea for scale up to EAA PAV level: Use a pure fabric wing, such

as the para-foil concept, which fills with air to develop lift.

Conveying the idea to a proper sewing mfg house, to make a conical/hemi-

spherical parafoil wing designed to hang beneath a ducted fan, will be

difficult, to say the least.

Ignore the idea that to do this right, one needs more money than I have

ever seen in my life.

Do what you can to test / prove the concept.

============================================================

April 2009-- I have learned a bunch. I have Mises's book,

"Theory of Flight".

I did some thought experiments around the task written above, quote:

[[quote]]

BEFORE I get an R/C heli kit:

Build something simple (wing only)--light, spit-and-plastic-

sheet-and-tape,

and see if you can get it to lift by holding a hair dryer

on it as the "ducted fan"...

[[unquote]]

The effective angle of attack is critical. The way that I originally

conceptualized this is inadequate, and will not work. It is easy to

be original when you do not know anything!

The basic idea of a "circular/conical wing" which lifts straight up

*might* be salvage-able, but the air flow baffling has to be perfect and

create attached (laminar) air flow of an appropriate speed. The "wing" itself

(for test purposes) can be a straight cone with some leading edge

decoration-- i.e. airfoil shape affects airplane trim/angle of attack

control and stall characteristics much more than it affects lift.

Accordingly to concentrate on lift, we can simplify the wing to a

flat cone.

But attached air flow has to hit the wing at precisely the right angle of

attack or lift will not develop. The critical piece is nozzle/baffle to

create correct angle of attack to the air flow from the ducted fan.

Accordingly I have been trying to invent a nozzle for the ducted fan...

I need to model this using a group of plastic bend-y straws which you can

buy at any supermarket.

I have all sorts of new airfoil "lift" questions... which Mises might

answer if I could read and understand the math... for example: What is the

best chord size of a wing to create the irrotational flow which we

need for lift, in this conical wing case?

... LATER after some experiments w straws.. I have decided to try a simple

cone baffle attached to a threaded rod which w/b fastened within a tube

This would be *hard* to build, but it can be done w the same techniques...