Grayhawk,
Please note that he
said;
“The elevator
bob weight was below the horizontal (elevator up, nose pitch
up) with flaps all the way up.”
That implies nose up trim not down trim.
Regards,
Bill Hannahan
--- On Mon,
2/23/09, Sky2high@aol.com <Sky2high@aol.com> wrote:
From:
Sky2high@aol.com <Sky2high@aol.com> Subject: [LML] Re: 360 in
a small-tail LNC2? To: lml@lancaironline.net Date: Monday,
February 23, 2009, 7:51 PM
Craig,
Uh, I believe you are flying high in the ASI yellow arc all
the time. That is quite beyond the max cruise design speed
of about 180 KIAS and should require the extra trim you mention.
BTW, mine runs out of down trim at 200 KIAS - so I push on the
stick a bit when racing. I suppose I could add a bungee cord
from the firewall to the stick for added trim. Gee, I run out of
left rudder trim also.
Anyone that put an engine with greater than the design HP should
expect to consider, uh, trim adjustments since the design
envelope has been pushed beyond standard limits.........
Grayhawk
In a message dated 2/23/2009 5:17:00 P.M. Central Standard Time,
craig@skybolt.net writes:
Hi Larry,
I think you are right about the incidence
being wrong in a lot of these airplanes. Mine will run out
of down trim over 210 kts. A quick look back and I can see
the elevator counterbalance sticking up about 3/8 inch. My
CG is perfectly to spec but at 210+ it doesn't seem to matter how
the airplane is loaded. It still needs gobs of down
trim. The problem is the faster the airplane goes the more
lift the wing wants to create. So to keep the airplane
flying level you have to reduce the angle of attack, that
means down trim. A full flying horizontal stab would be the
most efficient way around this.
Craig
Schulze Lancair 320 small tail.
-----Original
Message----- From: LHenney [mailto:LHenney@charter.net] Sent:
Sunday, February 22, 2009 2:36 PM To:
lml@lancaironline.net Subject: FW: 360 in a small-tail
LNC2?
Tom,
I had occasion to visit my CG limits for a
son's science project. Similarly I was assessing elevator
bob weight position relative to the horizontal tail at race
speeds and comparing airspeed data.
In my aircraft,
your premise would be wrong. That is, I have to move the
CG forward to flatten out the elevators to the horizontal tail
(which also increases speed (yes it's hard to believe)). As
opposed to changing CG, one might verify horizontal tail
incidence. Or more precisely all Lancair 320/ 360 I've
flown with have this same affect (bob weights a little high
at least minimally).
Regarding your CG comments, serious
pursuit of empty CG before any additional flight would be my
recommendation (imho). The phrase " way to far forward I think"
has me squirming.
Larry Henney
PS: In my estimation,
several 320/ 360 builders took the tail plane template and
transferred it to an incidence guide. The subsequent mistake
was mounting one's smart level atop the guide and setting the
tail plane at the requisite 1/4 to 1/2 degree nose down.
The mistake is missing the fact that the incidence guide off the
blue print was already 1/2 degree nose down. Thus reading 0 deg
on the smart level should have had the tail at the 1/2 degree
nose down angle. Many are actually 1 deg nose down. This
is not a problem. It just increases stability and costs 2-3
kts.
Just my 2 cents.
-----Original
Message----- From: Tom McNerney [mailto:dudewanarace@yahoo.com]
Sent: Friday, February 20, 2009 12:51 PM To:
lml@lancaironline.net Subject: RE:360 in a small-tail
LNC2?
Works great. I have a 400! I'm sure the
rest of small tail group would agree. Might have to move
your center of gravity back. (I need to) Only thing I can
say is that slow flight with full flaps isn't the
most comfortable, but now that I am aware of how it handles,
doesn't bother me a bit. My CG is way to far forward I
think, so that probably makes the slow flight a little
different.
On a side note.. I turned around and
looked at the tail the other day while indicating
200KTS. I could see the elevator counter weight, or
almost all of it. I didn't expect to see that at 200.
Maybe 100.. haha This leads me to believe that I have
a forward center of gravity. The big engine would explain
that. Once I get the plane on some scales, the only
thing I can think of is to move the battery. My
battery is behind the passenger seat.
Has anyone mounted a
battery behind the baggage compartment?
Advice?
Thanks Tom www.N54SG.com
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