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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Understanding that a lot of misinterpretation
can happen in reading or talking about things without actually being directed
in person on the subject article, I dismissed the following story. Now after
this post it has me curious again and I would be interested to hear comments from
people who may have been told the same. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The story comes as a result of a couple of
local pilots who were working on a well-known $2K arf from 2005-6 era that had
no reference lines on the fuse, nor measurements in the plans referring to
Thrustline or any clue as to where to start on fuselage angle to
engine-wing-stab setups. Communication with the designer resulted in the customer
being told that it should be done by appearance. (eg: the way you wish to
see your fuse angle in level flight cruise.)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>That seems very subject to interpretation
and I would think if a person were a few degrees off it would make a
significant difference on aerodynamic behavior during maneuvering. (mixing etc)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>There’s probably a post on this
somewhere, but Bob’s comment led me to think of that setup
dilemma. I’ve never seen or heard of an airplane kit/arf
without some reference to thrust line, until I heard my local friends told me
about this one.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Is this scenario familiar to anyone out
there? <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>(Gee, do I push send or not…….ok
I’ll send it.)<o:p></o:p></span></font></p>
<div>
<p class=MsoAutoSig><font size=3 color=navy face=Palatino><span
style='font-size:12.0pt;font-family:Palatino;color:navy'>Chris White<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
nsrca-discussion-bounces@lists.nsrca.org [mailto:nsrca-discussion-bounces@lists.nsrca.org]
<b><span style='font-weight:bold'>On Behalf Of </span></b>Bob Richards<br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, October 03, 2007
7:13 AM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">NSRCA
Mailing List</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [NSRCA-discussion]
Airplane angle of attack</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I never meant to draw any conclusion about the knife edge performance
of airliners or bombers in my original post. I was merely stating that the
reason we PATTERN FLIERS adjust the incidences of the wing and stab (ON OUR
PATTERN PLANES) has to do with aerobatic performance. As far as I know, the
reason the designers of airliners, bombers, and most full-scale airplanes pick
a incidence value has to do mainly with efficiency in cruise.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Bob R.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
<b><i><span style='font-weight:bold;font-style:italic'>rcmaster199@aol.com</span></i></b>
wrote:<o:p></o:p></span></font></p>
</div>
<blockquote style='border:none;border-left:solid #1010FF 1.5pt;padding:0in 0in 0in 4.0pt;
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<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I remember watching a clip of a full size multi engine bomber type in
test flight. The test pilot banked hard to knife edge near the ground (maybe
500 ft) for some unknown reason and swiftly proceeded to put it in. Don't
remember the plane's or test pilot's names. <o:p></o:p></span></font></p>
</div>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Full scale fuselages are designed to minimize drag as much as possible
(for max range) so they tend to be pencil thin comparatively speaking. Pencil
thin fuses do not fly knife flight well nor are they intended to do so. And the
higher the weight the worse the problem. At risk of being glib, that test pilot
found the outside of the envelope.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>MattK<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>-----Original
Message-----<br>
From: chris moon <cjm767driver@hotmail.com><br>
To: nsrca-discussion@lists.nsrca.org<br>
Sent: Tue, Oct 2 4:28 PM<br>
Subject: Re: [NSRCA-discussion] Airplane angle of attack<o:p></o:p></span></font></p>
<div id="AOLMsgPart_3_b6d597c8-f6a1-47c8-a976-7e61ea56aa74">
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>The optimum AOA on
airliners is a function of wing design. It's the <br>
operator's job to try and stay near the optimum AOA for maximum <br>
efficiency. Lighter gross weights require either higher altitudes or <br>
lower true airspeed to be most efficient. Likewise, heavier weights will <br>
have you faster and or lower. I guess what I'm saying is that the <br>
optimum AOA is essentially dictated by wing design and we juggle the <br>
other variables in order operate the wing as efficiently as possible. <br>
<br>
I have rolled the 737, 757, 767 and A320 in the simulator and they make <br>
poor pattern planes. I'm sure there is a significant downgrade for a <br>
single roll that loses 5000+ feet of altitude. Don't even ask about <br>
knife edge performance. <br>
<br>
Chris <br>
<br>
Bob Richards wrote: <br>
> That makes sense to me. The AOA depends on the load. In an extreme <br>
> case, very lightly loaded, I don't think you would want to fly with <br>
> the fuselage in a nose down attitude, that would probably be <br>
> inefficient. Better to have it slightly nose up in cruise with a full <br>
> load. JMHO. <br>
> Of course, the reason WE would trim wing incidence would have more to <br>
> do with overall flight characteristics during aerobatics, particularly <br>
> with pitch coupling in knife edge flight. <br>
> Bob R. <br>
> <br>
> <br>
> */chris moon /* wrote: <br>
> <br>
> Tried to post this before but it did not go through. <br>
> <br>
> The optimum cruise angle of attack for jetliners is somewhere between <br>
> 2.5 and 5 degrees nose up. Usually closer to 2.5 or 3 degrees for an <br>
> econ cruise. As fuel burns off and the gross weight goes down, the <br>
> airplane will need a lower angle of attack to maintain flight which <br>
> will take us away from our optimum angle (lower). So, we will either <br>
> climb to where the air is "thinner" and require a higher aoa <br>
> (angle of <br>
> attack) to get us back to the 2.5 or 3 degrees or, slow down and <br>
> maintain the lower altitude thus requiring us to increase the aoa <br>
> back <br>
> to optimum. The answer to your question is yes, a jetliner flies at a <br>
> nose high aoa in cruise. Lift from the fuselage would probably be <br>
> negligible other than "impact" lift - the force of the relative
wind <br>
> against the raised fuselage bottom. <br>
> <br>
> Chris <br>
> <br>
> <br>
> ------------------------------------------------------------------------ <br>
> <br>
> _______________________________________________ <br>
> NSRCA-discussion mailing list <br>
> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a>
<br>
> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion"
target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a> <br>
<br>
<o:p></o:p></span></font></p>
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</span></font></div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Climb to the top of the charts! Play Star Shuffle: the word
scramble challenge with star power. <a
href="http://club.live.com/star_shuffle.aspx?icid=starshuffle_wlmailtextlink_oct"
target="_blank">Play Now!</a> = <o:p></o:p></span></font></p>
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<div id="AOLMsgPart_4_b6d597c8-f6a1-47c8-a976-7e61ea56aa74"><pre
style='background:white'><tt><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;color:black'>_______________________________________________ NSRCA-discussion mailing list <a
href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a> <a
href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a> </span></font></tt><font
size=1 color=black><span style='font-size:9.0pt;color:black'><o:p></o:p></span></font></pre></div>
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<p class=MsoNormal style='margin-top:7.5pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Email and AIM finally together. You've gotta check out
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<p class=MsoNormal style='margin-top:7.5pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>_______________________________________________<br>
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NSRCA-discussion@lists.nsrca.org<br>
http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<o:p></o:p></span></font></p>
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