|
Notice: Improved two-anchor persistent flight
demonstrated by back-flipping and back bridling:
>>
AWES6946 Sep 5, 2012 Earlier today I was able to keep a toy
Delta Kite (Gayla Sky Spy) flying by towing it in brief cycles back and
forth between two spread anchors. The back of the kite was bridled just
like the front and the kite simply "back-flipped" faces at each end of
travel.
This is improved short cycle two-phase pumping, without an earlier problem
of reliably "turning the corner". Last year effective three-phase pumping
was demonstrated in public (WKM Windless Kite Festival). The latest design
is further evidence that persistent flight is simple and practical by
pumping inputs from the ground, for AWES and other applications. Video and
a public demo pending.
High value persistent flight was long considered one of the hardest
problems in aerospace, but it is not. Thanks
goes to the
AWES
Forum for helping solve real world challenges by freely shared
knowledge.
~ Dave Santos
==============================
[Recall the two-point disclosure:
AWES1389 in 2010 by JoeF
and the tri-tether cranking and pumping: May 27,
2009:
Tripod Tether by Dave Santos
and
AWES151 of May 27, 2009] |
|
11 October 2011
Testing Persistent Kite Flight by Pumping
(Stability Factors)
After several trial sessions of two-line persistent kite flight (toy
kite on a leader line towed by horizontal pumping line) the following
picture emerged: It is possible to sustain quasi-circular flight by this
means, but its too sensitive to the timing of the to-and-fro motion for
reliable passive flight. To fly a nearly circular pattern for an
extended session, a brief pumping tug must be skillfully applied each
way. Too little or too much of a tug, too soon or too late, and the kite
leaves the pattern, often entering towed "lock-out", with no easy way to
get back in the pattern. Often the lockout was a wandering loop
sliding off to the side. Passive feedback methods will be tested to
solve the instability.
By changing the geometry to long-stroke towing, a kite tows
stably in either direction. To make the
turn entails a brief unstable period as the kite once again finds its
stable flight attitude. Setting a small
tack (turning input) into the kite allows a tilted tow that sets up a
smooth turn, for an over all ovoid path, but a long tilted tow is less
stable in the real world than a long straight tow. T
he early conclusion from testing is that higher phase (more lines) kite
tugging is far more stable and practical for persistent flight, with
three-phase tri-tether tugging offering good passive stability.
CoolIP
~Dave Santos
11 October 2011
AWE4454
Note- A sufficiently high quality kiteplane skillfully enough controlled
can be maintained aloft on one line from one location. The kite glides
down to the end of its tether and regains altitude by a sharp tug, to set
up another glide phase. Skilled kite fliers already perform this flight
mode-
Alan Flying Zero Wind Kite .Thomas K Horvath, Hybrid 200
- YouTube
First glance on two unbaked methods
>
AWES1389
Posted By: joe_f_90032 Wed Mar 24, 2010 2:47 pm
The moment of first glance sometimes brings a gem of value,
sometimes not. The following two glances of enthusiasm
would not get posted if I passed away in an hour and thus
unable to develop the glance. So, I risk sharing the two
glances that may or may not be inventive, but for the moment
seem to have a kernel of something that someone might want
to explore (I hope I will be here tomorrow to invest on the
development of these two sparks):
Step-tall-launch method: Pedal
a kite left and right and left and right etc. between two pulleys while
the kite climbs higher in each cycle between the pulleys that spread
further apart also. Keep letting out line at each cycle until the kite is
in higher winds enough to sustain the kite. Then operate the system as an
effective AWECS. The details of the let-out mechanism have not been given
attention yet. Pedal in insufficient wind until kite reaches working
winds; then convert to AWECS for gains.
Other:
Spread-line center pulls up a third line when the two kites are
spread, one left and one right. Then guide the two spread kites
back to center which lets the spring-loaded central line back down. The
sprag clutch (driven by the central line) operates during the spread and
the release. The two kites stay flying: spread, center, spread, center,
spread, center, etc. The kites have their main tether that does not get
let out or in. This is not a
reeling method of kite tether as is a common AWECS method. I have not
seen this method. Note how a lateral line of many kites could be worked in
a kind of peristaltic rhythm with most kites (not the far left or the far
right kite) operating to release as it goes to relative center with one of
its adjacent neighbors while relative to the other adjacent neighbor kite
is spreading (and thus lifting central down lines).
If there is any novelty in these two glances, I offer such into public
domain without need for reference. CoopIP And if such glances
hold prior art, then I hope to be around past this hour to uncover and
credit those who have come before this moment with their findings and
instructions.
~JoeF
Comment and development of this topic will be occurring here.
All, send notes, drawings, and photographs!
Terms and aspects:
Related links:
Commentary is welcome:
- It does help to "(leave) the desk", just
as Dog insists, to empirically easily confirm that by power-to-weight
for AWE flight, kiteline beats "electricity" "to transmit power over a
distance" (to the surface). Or we can just sit at a desk, like Einstein,
and still get results.
Lets "pretend", which is
Einstein's Gedanken Method. We tow a toy kite in circles (use a
tri-tether) in still air with a watt of tow energy. Then we put a
motor/propeller on the kite and make it lift up a conductive tether. Now
we find that more than a watt of electricity is needed to fly just as
high in the same circle. The extra energy goes into waste heat of the
motor and tether, more aerodrag by a thick tether, higher AoA for the
same airspeed; induced drag of the propeller, and so on. Of course there
are some fancy physics to explain exactly why bare kite and line rocks,
but a child can see and feel that the kite and line is lighter (flying
weight), lower drag, and does not resistively heat up so readily as a
motor and electrical conductor.
Anyone who denies this is "in denial of what is already known" in
AWE. Of course electrical transmission is very practical along the
earth's surface and at small scales, where power-to-weight and safety
does not dominate the engineering.
~~DaveS
AWE4923
|