X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 09 Oct 2008 09:47:14 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d05.mx.aol.com ([205.188.157.37] verified) by logan.com (CommuniGate Pro SMTP 5.2.8) with ESMTP id 3205574 for lml@lancaironline.net; Thu, 09 Oct 2008 00:16:32 -0400 Received: from Sky2high@aol.com by imo-d05.mx.aol.com (mail_out_v39.1.) id q.d4b.3e33f799 (32913) for ; Thu, 9 Oct 2008 00:16:17 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Thu, 9 Oct 2008 00:16:17 EDT Subject: Re: [LML] Small Tail Incidence Data & Transponder Problems X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1223525777" X-Mailer: Unknown sub 5000 X-Spam-Flag:NO -------------------------------1223525777 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Wayne, 1. At cruise speed the wing induced nose up pitching moment is significant. We all have to trim nose down. If I understand the design process, the designer would first lay down the longeron line and describe the cruise flight parameters - For the LNC2, likely about 185 KTAS at around 9000 feet within certain weight/CG range. When the known wing is added, one could then add the necessary incidence for a certain sized horizontal stab with the elevator in trail. There are a lot of variables (and building variances) that all have to come together the way the designer expected. Maybe the incidence is right but wing wash out isn't quite right or the engine isn't at the expected angle, etc. It still would be interesting to compare this parameter to others and see if certain flight differences result from such differences. Perhaps the negative angle of incidence is too much, thus the need for the apparent downward displacement of the elevator to decrease the negative lift? Maybe we can do some flap comparisons next (cruise reflex angle) in that less than full reflex may have a beneficial trim effect and reduce drag a bit. Maybe not as I have not seen such an effect. 2. My vertical stab (and many others) have a slight twist along with a slight lack of symmetry in the rudder because of the influence of the balance weight (and skin moldings) during final assembly. Even though my rudder horn sticks out to the left in cruise, the rudder had to be trimmed to the "left". How do I know that the rudder sticks out a bit? By cleaning the bugs off the part that is exposed to the windstream. 3. Initially I had a spike transponder with about a 14" square ground plane mounted inside the wingtip just beyond the aileron bell crank access rib. The signal was no good at all, mainly because the carbon spar cap sucked up the radiation. I now use a 600 Kt Comant fin outside the bottom of the wing (a 12" ground plane inside the skin) and RG400 coax. It works well enough even though the Xpdr is a Terra. Good Luck, Scott Krueger In a message dated 10/8/2008 5:47:30 P.M. Central Daylight Time, waynnno@yahoo.com writes: I'm a buyer not builder. Reading the post re horiz stab incidence with great interest. With 2 in seats modest baggage, down elevator is required at speed. Looking back at horns-looks like several degrees down elevator. I plan to check horiz stab incidence per procedure yesterday, but short of using a saws-all and glass, what can I do if the stab incidence is not correct? I know the down elevator must be causing me drag would like to correct with out saws-all, is there another fix (flap reflex?? etc.) Also, at speed need left rudder to keep ball centered. I will play with trim tab this week. Any other ideas? Also, having intermittent transponder problem. Seems to always have problems with SOCAL in LA basin, but other radar environments sometimes have a problem sometimes not. Go figure. I have reply light flashing but they can't see me - other times no reply light. Tried cycling etc. Current transponder is a King KT76C. Internal antenna. Don't know about required matching transformer yet. Going into the shop this morning for trxpd checks. Plan to check frequency and power and check for matching transformer. But my mechanic says that he has had very limited / no success with "internal" antenna on other composites. Any list experience with internal antenna? Any suggestions on where internal antenna might be located? Thanks a lot. Really appreciate help from the list. Purchased AC last spring, but haven't flown it much due to taking it out of CA to avoid the sales tax (9.5% !!!). Plan to start flying a lot more and resolving these issues. Wayne Bailey 310-567-6877 N10RD LNC2 360 **************New MapQuest Local shows what's happening at your destination. Dining, Movies, Events, News & more. Try it out! 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Wayne,
 
1. At cruise speed the wing induced nose up pitching moment i= s=20 significant.  We all have to trim nose down.  If I understand the=20 design process, the designer would first lay down the longeron line and desc= ribe=20 the cruise flight parameters - For the LNC2, likely about 185 KTAS at around= =20 9000 feet within certain weight/CG range.  When the known wing is added= ,=20 one could then add the necessary incidence for a certain sized horizontal st= ab=20 with the elevator in trail.  There are a lot of variables (and building= =20 variances) that all have to come together the way the designer expected.&nbs= p;=20 Maybe the incidence is right but wing wash out isn't quite right or the engi= ne=20 isn't at the expected angle, etc.  It still would be interesting to com= pare=20 this parameter to others and see if certain flight differences result from s= uch=20 differences. Perhaps the negative angle of incidence is too much, thus the n= eed=20 for the apparent downward displacement of the elevator to decrease the negat= ive=20 lift?
 
Maybe we can do some flap comparisons next (cruise reflex angle) i= n=20 that less than full reflex may have a beneficial trim effect and=20 reduce drag a bit.  Maybe not as I have not seen such an effect.
 
2. My vertical stab (and many others) have a slight twist along wi= th a=20 slight lack of symmetry in the rudder because of the influence of the balanc= e=20 weight (and skin moldings) during final assembly.  Even thoug= h my=20 rudder horn sticks out to the left in cruise, the rudder had to be= =20 trimmed to the "left".  How do I know that the rudder sticks out a=20 bit?  By cleaning the bugs off the part that is exposed to the=20 windstream.
 
3. Initially I had a spike transponder with about a 14" square ground p= lane=20 mounted inside the wingtip just beyond the aileron bell crank access=20 rib.  The signal was no good at all, mainly because the carbon spar cap= =20 sucked up the radiation.  I now use a 600 Kt Comant fin outside the bot= tom=20 of the wing (a 12" ground plane inside the skin) and RG400 coax. It works we= ll=20 enough even though the Xpdr is a Terra.
 
Good Luck,
 
Scott Krueger
 
In a message dated 10/8/2008 5:47:30 P.M. Central Daylight Time,=20 waynnno@yahoo.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D3>
I'm a buyer not builder.
 
Reading the post re horiz stab incidence with great interest.
 
With 2 in seats modest baggage,  down elevator is required= at=20 speed.
 
Looking back at horns-looks like several degrees down=20 elevator.
 
I plan to check horiz stab incidence per procedure=20 yesterday,  but short of using a saws-all and glass,  what= can=20 I do if  the stab incidence is not correct?
 
I know the down elevator must be causing me drag would like to=20 correct with out saws-all,  is there another fix (flap reflex??= =20 etc.)
 
Also, at speed need left rudder to keep ball centered.  I=20= will=20 play with trim tab this week.  Any other  ideas?
 
Also,  having intermittent transponder problem.  Seem= s to=20 always have problems with SOCAL in LA basin,  but other radar=20 environments sometimes have a problem sometimes not. = Go=20 figure.  I have reply light flashing but they can't see me - ot= her=20 times no reply light.  Tried cycling etc.
 
Current transponder is a King KT76C.  Internal antenna.&nb= sp;=20 Don't know about required matching transformer yet. 
 
Going into the shop this morning for trxpd checks.  Plan t= o=20 check frequency and power and check for matching transformer. =20= But=20 my mechanic says that he has had very limited / no success with=20 "internal" antenna on other composites.
 
Any list experience with internal antenna? Any suggestions on w= here=20 internal antenna might be located?
 
Thanks a lot.  Really appreciate help from the list.
 
Purchased AC last spring,  but haven't flown it much due t= o=20 taking it out of CA to avoid the sales tax (9.5% =20 !!!).  Plan to start flying a lot more and resolving these=20 issues.
 
Wayne Bailey
310-567-6877
 
N10RD
LNC2
360
 
 




New MapQuest Loca= l shows what's happening at your destination. Dining, Movies, Events, N= ews & more. Try it out!
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