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<DIV><FONT size=2>You got the progression backward...</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Helical pitch is "steeper" at the root than the tip of the
prop. Since you want the whole prop to go forward 1 inch.. and the root
essentially has little movement it has to be steep to keep up with the
tip's large movement.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>If you want to simulate the same thing with an aileron.. you
would have more aileron chord near the root than the tip. This would
inhibit tip-stalls if the wing is constant chord (See the way the Four Star
series does it) </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>For a tapered wing, as is common in Pattern, to get the
"helical" effect you'd need the ailerons to make up 50% or more of the
difference in chord from root to tip. </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Depending on aileron deflection angle... a different %
chord ratio from root to tip would be required to achieve the
"helical" incidence(tapered or straight chord wing) For any given
tapered aileron, there will be one deflection angle that comes closest to
producing helical incidence. </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>If Helical incidence is the goal.. you'll have to choose at
what percentage of full aileron throw you want to hit helical incidence...
cunch some numbers and then cut the ailerons.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Constant chord ailerons in effect gives more AOA change at the
tip than the root with a tapered wing. (encouraging tip-stalls... this is why
its inadvisable to use flaperon function with a Pattern design when landing...
but spoilerons will help prevent dropping a wing.)</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>But.... it may be a good thing to get the higher AOA change
near the tip... </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>As pointed out... the Sig Four Star uses the tapered ailerons
in a manner which can approach a helical incidence</FONT><FONT size=2>, so its
been tried at least in one design series. Its probably been tried in a
Pattern design at some time... (if not... someone should try it)</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=natpenton@centurytel.net href="mailto:natpenton@centurytel.net">Nat
Penton</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, September 03, 2006 9:31
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Aero
design question</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Hey Tom</FONT></DIV>
<DIV><FONT face=Arial size=2>I'm not providing solutions - just putt'in
more wood on the fire. In steady state roll the least drag position of the
ailerons would be constant AOA root to tip. This would call for the percentage
of chord to progress linearly so that it would be double at the tip vs the mid
span position - no different than helical pitch. </FONT><FONT face=Arial
size=2>A ( severe ?) negative would occur, though, when the ailerons are
initiated, potentially causing a tip stall.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Martin Simmons provides a curve showing Cl vs %
of chord for the aileron. Going over 20% doesen't get you much for the
dollar - just much more servo wear and tear ( especially with the 160
<G> ).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>IMO it is not worth the extra work to stop the
ailerons short of the
tip.
Nat</FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Tom.Koenig@actewagl.com.au
href="mailto:Tom.Koenig@actewagl.com.au">Koenig, Tom</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, September 03, 2006 6:46
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Aero
design question</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff>Hi lads,</FONT></SPAN></DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff></FONT></SPAN> </DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff>This is what I have found to work well on my Merlin designs.
Now,I am ready to be corrected by those much more knowledgeable than
myself-I just do things empirically!</FONT></SPAN></DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff></FONT></SPAN> </DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff>I ended up using a percentage of the span of the panel (60% in
my case). I have tried various sizes, but somewhere in the 55-65 percentage
area worked well. I also came in from the tip by 30 mm, to get the
aileron out of the tip vortex. Now that I am flying a Synergy with the
ailerons running all the way out, I'm not so sure how much of a difference
it makes. Maybe servo life is a bit shorter, but that is hard to quantify
with the YS shaking things to bits anyway. As far as aileron chord dimension
goes, well, I have tried various sizes there too, and I do use different
percentages at the tip vs inboard aileron. I actually like to run a slightly
smaller percentage at the tip. I felt it to give me a more 'linear' feel to
the aileron. </FONT></SPAN></DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff>I also applied this to 'elevator' design. I wanted the tips of
the elevator to be less effective. I felt it helped pull corners better
afterwards, as in this case the inboard section is doing more of the
work. But now I am running a straight elevator hinge line on the
Synergy...............L.O.L</FONT></SPAN></DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff></FONT></SPAN> </DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff>It all gets very confusing, and in the end, what does it
all mean in 30 knot cross wind, sun in your eyes and thermals to
boot???</FONT></SPAN></DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff></FONT></SPAN> </DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff>Trim as good as possible, burn heaps of fuel ( or charge them
packs) and learn to fly the PIGS!!</FONT></SPAN></DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff></FONT></SPAN> </DIV>
<DIV><SPAN class=488440723-03092006><FONT face="Comic Sans MS"
color=#0000ff>Ofcourse good design helps.</FONT></SPAN></DIV>
<DIV><FONT face="Comic Sans MS" color=#0000ff></FONT> </DIV>
<DIV><FONT face="Comic Sans MS"><FONT color=#0000ff>T<SPAN
class=488440723-03092006>om</SPAN></FONT></FONT></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<B>On Behalf Of </B>Dean
Pappas<BR><B>Sent:</B> Sunday, 3 September 2006 4:58 AM<BR><B>To:</B>
NSRCA Mailing List<BR><B>Subject:</B> RE: [NSRCA-discussion] Aero design
question<BR><BR></FONT></DIV>
<DIV>Hi Gang,</DIV>
<DIV><FONT size=2><FONT size=3>The excellent axial rolling charecteristic
of some designs is due to a lot more than where the inboard end of the
ailerons end. Nonetheless, all of my designs used ailerons that ended far
from the fuse! The only downside is that having a bit of aileron in front
of the stab offers a useful trimming tool: trailing the ailerons up or
down will change the effective stab incidence, and this was a powerful
adjustment tool back when we didn't have plug-in adjustable
"everything".</FONT></FONT></DIV>
<DIV> </DIV>
<DIV>You note Akiba's well trimmed airplanes. There is some smart design
going on there!</DIV>
<DIV> </DIV>
<DIV>later,</DIV>
<DIV>
Dean</DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>-----Original Message----- <BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org on behalf of John
Ferrell <BR><B>Sent:</B> Sat 9/2/2006 7:48 AM <BR><B>To:</B> NSRCA Mailing
List <BR><B>Cc:</B> <BR><B>Subject:</B> Re: [NSRCA-discussion] Aero design
question<BR><BR></DIV></FONT>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV><FONT face=Arial size=2>I have spent a fair amount of time
considering this situation. I have concluded there is no reason to take
the risk of adding unnecessary turbulence to the empennage.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>In gentle maneuvering it probably has
little effect. In aggressive maneuvering (think snaps) it likely leads
to inconsistent behavior. Inboard ailerons may contribute additional
available force in 3D maneuvers (hanging on prop?). </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Other related considerations are aileron
shape and the hinging geometry. I also suspect fat fuselages reduce
these effects by dispersing the turbulence over a greater volume of
air.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Just my two cents worth!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>John Ferrell W8CCW<BR>"My
Competition is not my enemy"<BR><A
href="http://DixieNC.US">http://DixieNC.US</A><BR></FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial"><B>From:</B> <A
title=pentagon.systems@bigpond.com
href="mailto:pentagon.systems@bigpond.com">Peter Pennisi</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">'NSRCA Mailing
List'</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, September 01, 2006
8:35 PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [NSRCA-discussion] Aero
design question</DIV>
<DIV><BR></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">My current
model has ailerons which extend a fair way towards the fuselage
(Comp-ARF IMPACT) What effect does the turbulence coming off the
aileron have on the tail plane. I am currently building another IMPACT
(IMHO flies extremely well) which I am considering to reduce their
size by cutting and fixing the inboard part to the wing in an attempt
to clean up the airflow over the tail plane during rolling maneuvers .
The model does roll well but it could be
better.</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Am I barking
up the wrong tree – any thoughts!</SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"></SPAN></FONT> </P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Peter
</SPAN></FONT></P></DIV>
<P>
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