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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'>Wouldn’t that apply more to a “lifting”
wing rather than the symmetrical wings we use in pattern?</span></font></p>
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<p><b><i><font size=4 color=navy face="Brush Script MT"><span style='font-size:
13.5pt;font-family:"Brush Script MT";color:navy;font-weight:bold;font-style:
italic'>Jay </span></font></i></b><b><i><font size=4 color=navy
face="Brush Script MT"><span style='font-size:13.5pt;font-family:"Brush Script MT";
color:navy;font-weight:bold;font-style:italic'>Marshall</span></font></i></b><font
color=navy><span style='color:navy'> </span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style='font-weight:bold'>From:</span></b> </span></font><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>nsrca-discussion-bounces@lists.nsrca.org</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> [mailto:</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>nsrca-discussion-bounces@lists.nsrca.org</span></font><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Robert Harden<br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, March 07, 2008 9:36
AM<br>
<b><span style='font-weight:bold'>To:</span></b> NSRCA Mailing List<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [NSRCA-discussion]
[SPAM]Re: YS Questions+more - Rolls</span></font></p>
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style='font-size:12.0pt'> </span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Lance, I am taking a private
pilots ground school class, and the aerodynamics portion if it says that the
lower aileron produces lift, and a byproduct of lift is drag. The higher
aileron dumps lift and therefore has less drag. This condition creates
yaw. So, what we are doing in pattern, is to add differential between the
ailerons by raising the ailerons in the upward direction to increase it's
drag to match the lower ailerons drag so we don't get or minimize the yaw. Hope
that helps to understand what is going on.</span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>----- Original Message ----- </span></font></p>
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<p class=MsoNormal style='margin-left:.5in;background:#E4E4E4'><b><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial;font-weight:bold'>From:</span></font></b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> <a
href="mailto:homeremodeling2003@yahoo.com" title="homeremodeling2003@yahoo.com">krishlan
fitzsimmons</a> </span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><b><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial;font-weight:bold'>To:</span></font></b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> <a
href="mailto:nsrca-discussion@lists.nsrca.org"
title="nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</a> </span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><b><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial;font-weight:bold'>Sent:</span></font></b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> Thursday,
March 06, 2008 9:59 PM</span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><b><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial;font-weight:bold'>Subject:</span></font></b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> [SPAM]Re:
[NSRCA-discussion] YS Questions+more - Rolls</span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Lance, </span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Just a thought though, if going straight up, up
straight down, aren't the up and down ailerons both inducing equal drag,
no lift? I've often wondered if our straight up test is actually a perfect test
for this. It is for our up and down lines, but what about our 45's or
horizontals where we do indeed have lift on the low aileron and drag on the
other? This would create a different condition I'm guessing.. Probably small,
but still a little different because as I mention, both create drag on the up
or downline.. Still, it's the best test we have I guess.. </span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Chris <br>
<br>
<b><i><span style='font-weight:bold;font-style:italic'>Lance Van Nostrand
<patterndude@tx.rr.com></span></i></b> wrote:</span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>This thread is timely because I've been experimenting
with differential <br>
recently on a new design that seems to need it. Never needed it before on a <br>
pattern plane but now I might. My test is to fly very high, point the nose <br>
directly at the ground and roll pure aileron. Plane should be axial, but <br>
remember that axial is along the vertical CG, which may not be a line that <br>
pierces the wing LE/TE. You need to do it a few times to be sure that their <br>
is an axis that everything rotates around and that line is straight. If it <br>
wobbles, then we have an issue. Another way to determine this is to do <br>
unlimited rolls while flying straight up. If the airplane consistently arcs <br>
off its vertical line, you have a problem.<br>
<br>
Aerodynamics suggests two contributors. One is that the lowered aileron <br>
increases the lift of the airfoil and lift creates drag so this wing may <br>
pull the plane off axis. the other is that the spiral slipstream of the prop <br>
is pushing down on the right wing and up on the left so up/right aileron is <br>
more effective than up/left and down/left is more effective than down/right.<br>
<br>
The overall effect for most pattern planes is minimal and usually ignorable, <br>
but on IMAC style planes these factors can be significant and the resulting <br>
differential corrections may need to be adjusted with something as simple as <br>
a prop change (from 3 blade to 2 for example).<br>
<br>
the correction of course is to start playing with aileron differential. <br>
Given the contributors I've suggested, its not a given which way you go with <br>
the differential to correct the problem and the answer might not even be <br>
symmetrical.<br>
<br>
Note that contributor #1 above will change if you are flying upright or <br>
inverted, so it would seem that a correction for upright flight would simply <br>
exacerbate inverted flight, but contributor #2 is the same for any flight <br>
mode but is throttle dependent.<br>
<br>
--Lance<br>
<br>
----- Original Message ----- <br>
From: "Koenig, Tom" <br>
<TOM.KOENIG@ACTEWAGL.COM.AU>To: "NSRCA Mailing List" <br>
<NSRCA-DISCUSSION@LISTS.NSRCA.ORG>Sent: Thursday, March 06, 2008 4:45 PM<br>
Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls<br>
<br>
<br>
> My head is spinning!!! The more I think about this, the more questions I<br>
> have.........rather than answers!<br>
><br>
> Maybe the contra rotating prop set up on a Voodoo X( Nat??) maybe the<br>
> answer??<br>
><br>
> I still 'feel', that the best rolls I get are with a 0 differential set<br>
> up-BUT- somehow I 'drive' that wing to 0 ( or should that be some sort<br>
> of equilibrium??) during the rolls. Certainly in my case, it seems to be<br>
> Pilot dependant!!!<br>
> I'm starting to think that my rudder control has turned to the<br>
> proverbial trying to micro analyse what's happening!<br>
><br>
> Tom<br>
><br>
> -----Original Message-----<br>
> From: nsrca-discussion-bounces@lists.nsrca.org<br>
> [mailto:nsrca-discussion-bounces@lists.nsrca.org] On Behalf Of<br>
> shinden1@cox.net<br>
> Sent: Friday, 7 March 2008 9:15 AM<br>
> To: NSRCA Mailing List<br>
> Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls<br>
><br>
> what happens on a 4piont?<br>
> Bryan<br>
> ---- Del Rykert <DRYKERT2@ROCHESTER.RR.COM>wrote:<br>
>> The general consensus has been that the faster moving molecules over<br>
> the top surface don't require as big as a deflection as the aileron that<br>
> deflects towards the bottom of the plane. What one tries to achieve is<br>
> the plane tracks as purely straight on a string as possible while one<br>
> rolls both directions without introducing any yaw.<br>
>><br>
>> Del<br>
>><br>
>> ----- Original Message -----<br>
>> From: <br>
<GLMILLER3@SUDDENLINK.NET>>> To: "NSRCA Mailing List" <br>
<NSRCA-DISCUSSION@LISTS.NSRCA.ORG>>> Sent: Thursday, March 06, 2008 2:49
PM<br>
>> Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls<br>
>><br>
>><br>
>> > Nat and all you other aerodynamicists,<br>
>> ><br>
>> > I thought that the rational for "aileron differential"
was that<br>
> upward deflection causes more drag than downward deflection so to<br>
> equalize drag and prevent yaw with aileron deflection, aileron<br>
> differential is needed. It seems that you guys are now saying that<br>
> ain't so. Please elaborate.<br>
>> ><br>
>> > George<br>
>> ><br>
>> > ---- Nat Penton <NATPENTON@CENTURYTEL.NET>wrote:<br>
>> ><br>
>> > =============<br>
>> > IMO center hinged or top hinged is OK. With top hinge, to achieve<br>
> equal vertical travel of the trailing edge requires different angular<br>
> travel, up vs down. The objective is zero aerodynamic differential.<br>
>> ><br>
>> > Ron I don't think a fairing would prevent separation but, how are<br>
> you able to fair the gap using the top hinge ? Nat<br>
>> > ----- Original Message -----<br>
>> > From: ronlock@comcast.net<br>
>> > To: NSRCA Mailing List<br>
>> > Sent: Thursday, March 06, 2008 7:20 AM<br>
>> > Subject: Re: [NSRCA-discussion] YS Questions+more - Rolls<br>
>> ><br>
>> ><br>
>> > And while your at it, I'd appreciate some discussion of the
impact<br>
> of the top hinge system as seen on Viavat, and Prestige birds - (top<br>
> hinged, with fairing that eliminates the gap at deflection)<br>
>> ><br>
>> > Thanks, Ron Lockhart<br>
>> ><br>
>> > -------------- Original message -------------- <br>
>> > From: vicenterc@comcast.net<br>
>> ><br>
>> > Nat,<br>
>> ><br>
>> > Could you explain why the differential should be different for<br>
> non-center hinged? I understand that the mechanical configuration of<br>
> non-center hinged requires differential to obtain same travel in both<br>
> directions. However, the travel up and down should be close to equal.<br>
>> ><br>
>> > Thanks,<br>
>> ><br>
>> > --<br>
>> > Vicente "Vince" Bortone<br>
>> ><br>
>> > -------------- Original message -------------- <br>
>> > From: "Nat Penton" <br>
<NATPENTON@CENTURYTEL.NET>>> ><br>
>> > Tom<br>
>> > It's just something that is peculiar to the Southern<br>
> Hemisphere.<br>
>> ><br>
>> > Changing wing incidence will not help. Unless things are really<br>
> screwed up <G>, at our roll rates, centrifugal forces are too low to<br>
> cause a problem. You want zero differential, aero speaking ( same<br>
> up/down if center hinged ).<br>
>> ><br>
>> > I find the best check is the fast half-roll in the vertical up.<br>
> Regards Nat<br>
>> > ----- Original Message ----- <br>
>> > From: Koenig, Tom<br>
>> > To: NSRCA Mailing List<br>
>> > Sent: Wednesday, March 05, 2008 7:24 PM<br>
>> > Subject: Re: [NSRCA-discussion] YS Questions+more<br>
>> ><br>
>> ><br>
>> > Hi Troy!<br>
>> ><br>
>> > Thanks for the info. I thought you would be toiling away on<br>
> the next developmental stage of these engines!!<br>
>> ><br>
>> > Hopefully soon, I can find the time to get flying again. I am<br>
> looking forward to running this little beast. I am still a little<br>
> concerned in keeping it quiet though.<br>
>> ><br>
>> > Four blade props? I have some of the 18.1 x 12 two bladers<br>
> but I just cant see how I'll shut the thing up with these paint<br>
> stirrers??<br>
>> ><br>
>> > Also-one more question to any of you out there in pattern<br>
> land.<br>
>> ><br>
>> > I have struggled with aileron differential for years. I am<br>
> just not happy with the rolls. I have tried various design fixes-but<br>
> about the only one that seems to work is to get the wing back to 0-0 (<br>
> which can be achieved by a few ways, design, mix or thumbs) Differential<br>
> itself does not seem to work if the wing is POA ( well...it works for<br>
> half the roll !)<br>
>> > Another black magic fix appears to be to run parallel<br>
> ailerons-but this only 'sorta' seems to fix it. I like the feel of<br>
> equal% chord ailerons however.<br>
>> ><br>
>> > I am frustrated with it-I like my planes to roll as if they<br>
> had a string up its ...........well you know!<br>
>> ><br>
>> > OK-any 'secrets' I need to know??? Very good elevator work<br>
>> > fixes it ( hence my 0-0 comment)<br>
>> ><br>
>> > Tom<br>
>> ><br>
>> ><br>
>> >
--------------------------------------------------------------------<br>
>> > ----<br>
>> ><br>
>> ><br>
>> > _______________________________________________<br>
>> > NSRCA-discussion mailing list<br>
>> > NSRCA-discussion@lists.nsrca.org<br>
>> > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<br>
>> ><br>
>> ><br>
>> >
--------------------------------------------------------------------<br>
>> > ----------<br>
>> ><br>
>> ><br>
>> > _______________________________________________<br>
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>> > NSRCA-discussion@lists.nsrca.org<br>
>> > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion<br>
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