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AOA Indicator

Posted: Fri May 09, 2014 3:33 pm
by mkoxxy
As suggested, I am starting a new thread, split off from "Air Speeds in
cold weather".

Here is Kess' last message:


'Kess Blaswich' kessb@wavecable.com [Earthstar_Aircraft] <
Earthstar_Aircraft@yahoogroups.com>

11:22 AM (1 hour ago)

to Earthstar_Airc.

Martin, I like your interest in an AOA indicator. The prices have come way
down, and there are also some experimental projects to make one really
cheap. I like you, don’t have an issue with the trim knob, even when I
forget which way to turn it. Like Cessna’s just turn a little bit and see
if the stick pressure goes with you or the wrong way, easy deal just turn
the other way until the pressure is neutralized. I rarely move the setting
in my single place, and is set for neutral at about 100 mph and even
slowing to 80 requires little stick pressure change. But I do like the AOA
thing, as we have no cowl to peer over as a reference when getting the nose
higher, and I think that a glide could be fine tuned with such a device.
Hmmmmm, I see another project on the horizon. If I can make a homemade high
powered LED landing light, why knot an AOA indicator device?

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

The Dynon EFIS have an AOA option built into the software. The upgrade
essentially consists of a replacment pitot-with-AOA-aperture, for $200
(unheated version). I don't think there is much magic in the pitot - just a
second tube, at the right angle, and with the right aperture should do it.
The cost would not be the major hurdle, but they come in only straight and
90° versions.

Since our pitot tubes exit the nose at around 45°, then take a bend to
horizontal, I was figuring I could simply sling another tube under it, but
leave it straight. The fact that the two openings may be a couple inches
apart should not matter. I would need to know what the approximate ratio in
aperture or diameter is between the two openings on the Dynon pitot -
approximate, because the built-in calibration option will take care of
minor deviations from the Dynon version. Does anyone have a Dynon AOA pitot
assembly they could measure for me?

I like the option to have an audible indicator (accelerating pings, or
increase in pitch as I get closer to stall), since I plan to have my eyes
outside the cockpit, especially during landing approaches.

Martin

eGull, hoping to fly this summer

Re: AOA Indicator

Posted: Fri May 09, 2014 4:32 pm
by tgulldave
If you lower the flaps, the stall happens at a lower speed.
I've never understood how an AOA indicator works at different flap
settings.

Re: AOA Indicator

Posted: Fri May 09, 2014 5:20 pm
by earthstaraircraft
I have a lot of time flying with AOA and have
Never needed it. I think it is a waist of money and
A distraction. Since I don't fly IFR.
Save your time and money to bye more electricity for
Your eGull or gas if you still use that stuff.
I don't mean to be a spoil sport but some times
We want to solve problems that we don't really have.
Happy Flying
Mark

Sent from my iPhone

Re: AOA Indicator

Posted: Fri May 09, 2014 6:02 pm
by mkoxxy
If I understand this right, this is exacly why an AOA works: speed is less
important than angle of attack. For AOA purposes, the two-probe setup cares
only about the difference in pressure, not the actual pressure (=speed).

But for now, I think I will take Mark's advice - you cannot argue with
experience. And if I ever feel like an AOA would be good to have, it is
easy to retrofit. I have already drilled the second hole through the pitot
assembly flange, then bondoed it shut.

Re: AOA Indicator

Posted: Fri May 09, 2014 6:21 pm
by k1w1art
I agree Flying at this level is meant to be fun not cluttered up with stuff. Although I do have a VSI in my panel. Less is more time to enjoy

Art

Re: AOA Indicator

Posted: Fri May 09, 2014 9:02 pm
by gjcarter34
I second Marks opinion. I bought a plane that already had an AOA installed and I flew with it for awhile. The Earthstar is just so easy to fly and land that I couldn't imagine it being of any use. After a few hours of flying my odyssey, it just became part of me, I felt like I grew wings. Though I have been flying for many years, I was completely comfortable flying and landing the odyssey while never looking at any indicator. I always error with caution and take my time to learn the plane I'm flying. The first thing I do is go up high and practice slow flight and stalls and I keep current with them. The Earthstar will give you proper stall warning and recovery time. I recently ferried a bonanza and on the way back I was performing stalls, I'm glad I did as it stalled with no buffeting or warning. Needless to say with this plane I glance at the airspeed indicator on approach.
When I give flight reviews I'm always surprised by the number of pilots that once they received their license have never practiced slow flight or stalls. As we properly practice and master them during the review they always seem relieved knowing they can recover and control the airplane.

Gary

Re: AOA Indicator

Posted: Fri May 09, 2014 9:32 pm
by mkoxxy
This may be expanding the topic a bit, but while we have your attention:
what flight instruments are actually helpful when flying a Gull or Odyssey?
Is a single solid state EFIS like the Dynon D6 or D60 sufficient? Or have
tablet-based "avionics" become safe and useful enough by now?

Due to the limited range (until battery tech improves), I will never go
cross-country, but I hope to be able to do some light soaring.

Re: AOA Indicator

Posted: Sat May 10, 2014 6:10 pm
by allan_farr
---In Earthstar_Aircraft@yahoogroups.com, <gjcarter34@...> wrote :
Because the AOA indicator measures AOA not airspeed?


"If you lower the flaps, the stall happens at a lower speed.
I've never understood how an AOA indicator works at different flap settings".

Re: AOA Indicator

Posted: Sun May 11, 2014 1:44 pm
by rahulchoudhary73
this is a good read, http://www.boeing.com/commercial/aeroma ... story.html

The pitch level indicator (PLI) in fig11 is interesting. As the Gull has large safety margins, it's not as necessary; and then it looks like a compact display overall, at more expense

2 cents,
Rahul

Re: AOA Indicator

Posted: Mon May 12, 2014 2:53 am
by tgulldave
Thanks Rahul, that article explains a lot.