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<DIV><FONT face=Arial size=2>Robert,</FONT></DIV>
<DIV><FONT face=Arial size=2>you are correct. In addition to your class
you could also see that information at the top of my second paragraph.
Problem with this is that if we correct for upright flight, we exacerabate for
inverted. There are other design factors and trim factors that can reduce
or increase this problem.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>--Lance</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=rharden1@cox.net href="mailto:rharden1@cox.net">Robert Harden</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, March 07, 2008 8:35
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] [SPAM]Re:
YS Questions+more - Rolls</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>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.</FONT></DIV>
<DIV><FONT face=Arial 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=homeremodeling2003@yahoo.com
href="mailto:homeremodeling2003@yahoo.com">krishlan fitzsimmons</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> Thursday, March 06, 2008 9:59
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [SPAM]Re: [NSRCA-discussion]
YS Questions+more - Rolls</DIV>
<DIV><BR></DIV>
<DIV>Lance, </DIV>
<DIV> </DIV>
<DIV>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.. </DIV>
<DIV> </DIV>
<DIV>Chris <BR><BR><B><I>Lance Van Nostrand
<patterndude@tx.rr.com></I></B> wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">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" <TOM.KOENIG@ACTEWAGL.COM.AU><BR>To: "NSRCA Mailing List"
<NSRCA-DISCUSSION@LISTS.NSRCA.ORG><BR>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:
<GLMILLER3@SUDDENLINK.NET><BR>>> To: "NSRCA Mailing List"
<NSRCA-DISCUSSION@LISTS.NSRCA.ORG><BR>>> 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"
<NATPENTON@CENTURYTEL.NET><BR>>> ><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>>> >
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> ----------<BR>>> ><BR>>> ><BR>>> >
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<DIV><STRONG><EM><FONT face="comic sans ms" color=#0000bf size=3>Chris
</FONT></EM></STRONG></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
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