?? Lift Reserve Indicator ??

"Bill Daniels" bildan@comcast-dot-net wrote in message
...

"Dan, U.S. Air Force, retired" wrote in message
...
.Blueskies. wrote:
"Montblack" wrote in message
...

First time I've stumbled across one of these:

Lift Reserve Indicator

http://home.hiwaay.net/~sbuc/journal/liftreserve.htm
"One of the AOA systems that has been around the longest is the Lift
Reserve Indicator. This unit was developed in the 1970's and has been
offered in a couple of different variations since then. There is
considerable controversy over just what the LRI actually measures and
how
it operates, but when the price of the analog unit was recently reduced
substantially, it got my attention. Since the panel of 399SB is rather
unconventional, I had included a small backup airspeed indicator.
However, the AI was never used since I rely on the RMI uEncoder for
pitot
info, so I decided to replace the AI with the LRI since it could also
serve as a backup airspeed indicator. The decision was easier since the
LRI would fit in the same space as the little AI and was in the pilot's
angle of vision."

http://www.liftreserve.com/
Company website - InAir Instruments


Montblack


Interesting, delta P between two sources, one more or less pointing
forward and one more or less pointing downward. I suppose the indicator
has a pressure diaphragm inside it linked to the needle...

I want an AOA indicator for the BD4 someday...

Hmmmmmm.......



A couple of years ago Kitplanes had an article about and AOA sytem
that
used 2 ports flush with the wing surface near the wing tips. It's a
simplified version of a system the military has been using for decades.
The military version uses a conical probe sticking out of the side of
the
fuselage. There are two sets of slots a few degrees part facing towards
the front of the airplane. These slots are ports that send air pressure
to
two sensing chambers. Here's where they decided to get complicated: the
cone is then driven until the chamber measure equal pressure. The cone's
position is then transmitted to an indicator. Obviously the system isn't
for single engine tractor airplane. The 3.125" indicator is a tad big
for
most homebuilts, but does contain switches for stall warning and AOA
indexer lights. It seems to me some enterprising electronics genius
should
be able to design a simple system that does all this in solid state.

Dan, U.S. Air Force, retired

I'd also like an electronic AOA indicator. There are several probes that
work on three pressure pickups like
(http://www.cgmasi.com/aviation/index.html). In sailplanes we can just
tape a couple of yarns of the side of the canopy and mark the inside with
grease pencil.

bildan



Light :-)
Simple :-)
Reliable :-)
But, won't work for single engine tractor airplanes :-(

"wright1902glider" wrote in message
oups.com...
The last vane-type indicator I witnessed was hanging on the strut of a
New Standard DB-25 (circa 1926). It was an airspeed indicator and
appeared to function quite well from my perspective in the forward-left
front seat.

Orville Wright used a vane-type device in the autopilot system he
invented. While this was the world's first functional autopilot, it
never became popular. Sperry's gyroscopic autopilot system hit the
market shortly after, and was superior.

I'm not familiar with any vane-type AOA indicators that could be
mounted on a strut, but that doesn't mean that they didn't exist. If
anyone knows of one, I'd like to see it.

Harry

I don't recall whether I saw the one on the New Standard personally, or in a
picture, as it was still flying at Sun-n-Fun a couple of years ago. It may
well have been a picture as I didn't go up. IIRC, it looked, more than
anything else, an AoA calibrated as airspeed at some typical
loading--probably gross.

..Blueskies. wrote:
"Bill Daniels" bildan@comcast-dot-net wrote in message ...

"Dan, U.S. Air Force, retired" wrote in message ...


A couple of years ago Kitplanes had an article about and AOA sytem that used 2 ports flush with the wing surface
near the wing tips. It's a simplified version of a system the military has been using for decades. The military
version uses a conical probe sticking out of the side of the fuselage. There are two sets of slots a few degrees part
facing towards the front of the airplane. These slots are ports that send air pressure to two sensing chambers.
Here's where they decided to get complicated: the cone is then driven until the chamber measure equal pressure. The
cone's position is then transmitted to an indicator. Obviously the system isn't for single engine tractor airplane.
The 3.125" indicator is a tad big for most homebuilts, but does contain switches for stall warning and AOA indexer
lights. It seems to me some enterprising electronics genius should be able to design a simple system that does all
this in solid state.

Dan, U.S. Air Force, retired

I'd also like an electronic AOA indicator. There are several probes that work on three pressure pickups like
(http://www.cgmasi.com/aviation/index.html). In sailplanes we can just tape a couple of yarns of the side of the
canopy and mark the inside with grease pencil.

bildan



Here is an electronic version: http://advanced-control-systems.com/AOA/aoa.htm

Two pickups; one on the top of the wing and one on the bottom...


That's the system I waas thinking of.


Dan, U.S. Air Force, retired

Richard Lamb wrote:
Icebound wrote:

".Blueskies." wrote in message
t...


Interesting, delta P between two sources, one more or less pointing
forward and one more or less pointing downward.




Basically a stall horn, with the lowered pressure activating a meter
instead of a sound-producing reed. As the pressure falls at the horn,
the needle swings deeper toward the red.


Are we sure that the sensor is a pressure type sensor?

The A-4 Skyhawk uses a paddle type vane on the side of the aircraft's nose.
I'm assuming a simple potentiometer is attached to the vane to read
position.
Very straight forward mechanical approach.

There were/are 2 variations of the system you describe. The one on the
A-4, T-39 etc do have resistance strips and switches inside the can on
the otherside of the skin from the vane. The one I have only has
switches. I don't know what it came off of. I am going to modify it to
synchro or resistance depending on how energetic I feel.

Dan, U.S. Air Force, retired

"Dan, U.S. Air Force, retired" wrote in
news:w3xIf.1376$et.1235@dukeread12:

.Blueskies. wrote:
"Bill Daniels" bildan@comcast-dot-net wrote in message
...

"Dan, U.S. Air Force, retired" wrote in message
...


A couple of years ago Kitplanes had an article about and AOA
sytem that used 2 ports flush with the wing surface
near the wing tips. It's a simplified version of a system the
military has been using for decades. The military version uses a
conical probe sticking out of the side of the fuselage. There are
two sets of slots a few degrees part facing towards the front of the
airplane. These slots are ports that send air pressure to two
sensing chambers. Here's where they decided to get complicated: the
cone is then driven until the chamber measure equal pressure. The
cone's position is then transmitted to an indicator. Obviously the
system isn't for single engine tractor airplane. The 3.125"
indicator is a tad big for most homebuilts, but does contain
switches for stall warning and AOA indexer lights. It seems to me
some enterprising electronics genius should be able to design a
simple system that does all this in solid state.

Dan, U.S. Air Force, retired

I'd also like an electronic AOA indicator. There are several probes
that work on three pressure pickups like
(http://www.cgmasi.com/aviation/index.html). In sailplanes we can
just tape a couple of yarns of the side of the canopy and mark the
inside with grease pencil.

bildan



Here is an electronic version:
http://advanced-control-systems.com/AOA/aoa.htm

Two pickups; one on the top of the wing and one on the bottom...


That's the system I waas thinking of.


Dan, U.S. Air Force, retired

I plan on putting this one in my Sonex:

http://www.ch601.org/resources/aoa/aoa.htm

--
-- ET :-)

"A common mistake people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools."---- Douglas Adams

Hmmm....

http://www.waldowrights.com/pictures.asp

Check out the 8th photo down, left hand column. Watever that thingy
is... I remember it being an airspeed indicator, but I could be wrong.
Its been a while.

I shared a hangar with these guys at Celebrate Freedon 2004 in Camden,
SC. Rob is a really nice guy and is only about 6'7". Dunno how he fits
in that plane. His tent was off to the left of Kermett Weeks' P51-C. I
was to the right and behind. The Berlin airlift Museum's C-54 was just
to the right of me. I went up with him and 3 other fellows at dusk on
Sunday night after the show. Extremely cool.

Any guesses on who invented the vane-type AOA? I'm gonna have to look
that one up. I know that Orville was working with similar devices from
about 1909 through the 1920's. Early Wright machines were extremely
pitch sensitive. Most had an AOA window of -2 to +10 degrees. Any more
or less could, and frequently did, mean death.

Harry

"wright1902glider" wrote in message
oups.com...
Hmmm....

http://www.waldowrights.com/pictures.asp

Check out the 8th photo down, left hand column. Watever that thingy
is... I remember it being an airspeed indicator, but I could be wrong.
Its been a while.

I shared a hangar with these guys at Celebrate Freedon 2004 in Camden,
SC. Rob is a really nice guy and is only about 6'7". Dunno how he fits
in that plane. His tent was off to the left of Kermett Weeks' P51-C. I
was to the right and behind. The Berlin airlift Museum's C-54 was just
to the right of me. I went up with him and 3 other fellows at dusk on
Sunday night after the show. Extremely cool.

Any guesses on who invented the vane-type AOA? I'm gonna have to look
that one up. I know that Orville was working with similar devices from
about 1909 through the 1920's. Early Wright machines were extremely
pitch sensitive. Most had an AOA window of -2 to +10 degrees. Any more
or less could, and frequently did, mean death.

Harry


I'm pretty sure that the thingy in the photo is the airspeed indicator of
the New Standard, and is the one that looks to me like an AoA indicator
marked as airspeed. IMHO, it would have worked quite well for the purpose
intended in those days (when no controller ever requested you to "say
airspeed"); but would not have been an especially accurate measure of AoA
due to the interference of the wings. In short, lousy for verifying
engineering specs, and better than a more accurate instrument for just
keeping pilots and passengers healthy and airplanes intact.

Peter