REFLECTOR:CG Test
KeithHallsten
reflector@tvbf.org
Sat, 24 Jan 2004 12:01:57 -0800
This is a multi-part message in MIME format.
------=_NextPart_000_0018_01C3E271.DDD65960
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
John,
I think the point of doing the weight and balance measurements and =
calculations is to have documentation of the acceptable C.G. range. =
Then some proposed loading can be checked before flight to assure that =
is within the acceptable range. This is both good practice and required =
by regulation: it's the "W" in the "AROW" required documents list.
Maybe because of my engineering background, calculating the center of =
gravity location seems like a very logical thing to do. I plan to =
calculate W&B for all of my proposed loading configurations, then =
compare those numbers to the flight characteristics experienced. That =
way I will know what flight characteristics to expect when I'm proposing =
to fly at some different loading configuration for which I calculate the =
W&B numbers.
Keith Hallsten
----- Original Message -----=20
From: John Dibble=20
To: reflector@tvbf.org=20
Sent: Saturday, January 24, 2004 10:50 AM
Subject: Re: REFLECTOR:CG Test
Jim,
I appreciate your comments. I suspect a weight/balance would confirm =
an aft cg loading according to the numbers that Velocity provides. What =
I am trying to do here is establish a limit specific to my plane which =
may be different from the standard assuming there are small differences =
in how each plane is built. Scott S told me that, for a standard =
Velocity, typically 170 lbs in the front seat is enough to put you =
within the aft cg limit. So perhaps my plane is different, or maybe the =
original cg measurements are off. In any case I think an actual flying =
stall test is more meaningful than measurements on the ground. Of =
course with flying there is risk involved and the weight/balance =
measurement is essential before first flight when you know nothing about =
how it will fly. My plane has 280 hours (75 of which are mine), so I =
know it flies ok and I'm looking to fine tune (determine with more =
certainty) my aft cg limit and hopefully avoid adding weight to the =
nose. From recent reflector discussions I felt I understood the causes =
and onset indicators of a deep stall as well as how to recover from it =
(altitude, prop pitched for power, moveable weights) and felt =
sufficiently comfortable to stall the canard near the aft cg limit. I =
think doing a weight and balance measurement now is like measuring the =
length of the bungee cord after having already jumped off the bridge. =
If anyone disagrees, please tell me.
John
Jim Sower wrote:
Having done what you have done, I would be inclined to muster up some =
friends and do a
weight/balance with the fuel load you tested with, you *personally* =
sitting in the
pilot's seat, and the weights you used just as close as you can place =
them to where
they were in the back seat.
Just to be sure .... Jim S.
John Dibble wrote:
I decided to do a test to determine my aft cg limit as suggested by
Scott B. My balance calculations for my SRG indicate I will be aft cg
with less than 250 lbs in the front seats. I weigh 170 so this needs to
be resolved and nose weight added if needed. I put 8 x 10lb weights in
the copilot seat. At 7500' I trimmed for 75-80kn and pulled back until
the canard stalled at 60kn. It took all the aft stick and I had to trim
to about 70kn in order to stall the canard. The canard motion was
gentile and the plane was a bit wobbly, but stable. One-by-one I moved
the weights to the rear seat and repeated the stall. Each time the
canard motion was less pronounced. With all the weights in the back
seat the canard just kind of mushed down at 58kn. In all cases I had to
maintain aft stick pressure to get slow enough to stall and never had to
push the stick forward. I should add that I have 3 leading edge
vortilons and one trailing edge fence inboard of the aileron on each
wing. So it appears that I do not need to add any nose weight. Anyone
agree/disagree?
John
=20
_______________________________________________
To change your email address, visit =
http://www.tvbf.org/mailman/listinfo/reflector
Visit the gallery! www.tvbf.org/gallery
user:pw =3D tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
------=_NextPart_000_0018_01C3E271.DDD65960
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE></TITLE>
<META http-equiv=3DContent-Type =
content=3Dtext/html;charset=3DISO-8859-1>
<META content=3D"MSHTML 6.00.2800.1276" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY text=3D#000000 bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>John,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I think the point of doing the weight =
and balance=20
measurements and calculations is to have documentation of the acceptable =
C.G.=20
range. Then some proposed loading can be checked before flight to =
assure=20
that is within the acceptable range. This is both good practice =
and=20
required by regulation: it's the "W" in the "AROW" required =
documents=20
list.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Maybe because of my engineering =
background,=20
calculating the center of gravity location seems like a very logical =
thing to=20
do. I plan to calculate W&B for all of my proposed loading=20
configurations, then compare those numbers to the flight characteristics =
experienced. That way I will know what flight characteristics to =
expect=20
when I'm proposing to fly at some different loading configuration for =
which I=20
calculate the W&B numbers.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Keith Hallsten</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Daminetech@bluefrog.com =
href=3D"mailto:aminetech@bluefrog.com">John=20
Dibble</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, January 24, =
2004 10:50=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: REFLECTOR:CG =
Test</DIV>
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><FONT=20
face=3DArial size=3D2></FONT><BR></DIV>Jim,<BR>I appreciate your =
comments. I=20
suspect a weight/balance would confirm an aft cg loading according to =
the=20
numbers that Velocity provides. What I am trying to do here is =
establish=20
a limit specific to my plane which may be different from the standard =
assuming=20
there are small differences in how each plane is built. Scott S =
told me=20
that, for a standard Velocity, typically 170 lbs in the front seat is =
enough=20
to put you within the aft cg limit. So perhaps my plane is =
different, or=20
maybe the original cg measurements are off. In any case I think =
an=20
actual flying stall test is more meaningful than measurements on the=20
ground. Of course with flying there is risk involved and =
the=20
weight/balance measurement is essential before first flight when you =
know=20
nothing about how it will fly. My plane has 280 hours (75 of =
which are=20
mine), so I know it flies ok and I'm looking to fine tune (determine =
with more=20
certainty) my aft cg limit and hopefully avoid adding weight to =
the=20
nose. From recent reflector discussions I felt I understood the =
causes=20
and onset indicators of a deep stall as well as how to recover from it =
(altitude, prop pitched for power, moveable weights) and felt =
sufficiently=20
comfortable to stall the canard near the aft cg limit. I think =
doing a=20
weight and balance measurement now is like measuring the length of the =
bungee=20
cord after having already jumped off the bridge. If anyone =
disagrees,=20
please tell me.<BR><BR>John<BR><BR>Jim Sower wrote:<BR>
<BLOCKQUOTE cite=3Dmid4011F9AF.FCFC2173@frontiernet.net =
type=3D"cite"><PRE wrap=3D"">Having done what you have done, I would be =
inclined to muster up some friends and do a
weight/balance with the fuel load you tested with, you *personally* =
sitting in the
pilot's seat, and the weights you used just as close as you can place =
them to where
they were in the back seat.
Just to be sure .... Jim S.
John Dibble wrote:
</PRE>
<BLOCKQUOTE type=3D"cite"><PRE wrap=3D"">I decided to do a test to =
determine my aft cg limit as suggested by
Scott B. My balance calculations for my SRG indicate I will be aft cg
with less than 250 lbs in the front seats. I weigh 170 so this needs to
be resolved and nose weight added if needed. I put 8 x 10lb weights in
the copilot seat. At 7500' I trimmed for 75-80kn and pulled back until
the canard stalled at 60kn. It took all the aft stick and I had to trim
to about 70kn in order to stall the canard. The canard motion was
gentile and the plane was a bit wobbly, but stable. One-by-one I moved
the weights to the rear seat and repeated the stall. Each time the
canard motion was less pronounced. With all the weights in the back
seat the canard just kind of mushed down at 58kn. In all cases I had to
maintain aft stick pressure to get slow enough to stall and never had to
push the stick forward. I should add that I have 3 leading edge
vortilons and one trailing edge fence inboard of the aileron on each
wing. So it appears that I do not need to add any nose weight. Anyone
agree/disagree?
John
</PRE></BLOCKQUOTE><PRE wrap=3D""><!---->
_______________________________________________
To change your email address, visit <A class=3Dmoz-txt-link-freetext =
href=3D"http://www.tvbf.org/mailman/listinfo/reflector">http://www.tvbf.o=
rg/mailman/listinfo/reflector</A>
Visit the gallery! <A class=3Dmoz-txt-link-abbreviated =
href=3D"http://www.tvbf.org/gallery">www.tvbf.org/gallery</A>
user:pw =3D tvbf:jamaicangoose
Check new archives: <A class=3Dmoz-txt-link-abbreviated =
href=3D"http://www.tvbf.org/pipermail">www.tvbf.org/pipermail</A>
Check old archives: <A class=3Dmoz-txt-link-freetext =
href=3D"http://www.tvbf.org/archives/velocity/maillist.html">http://www.t=
vbf.org/archives/velocity/maillist.html</A>
</PRE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
------=_NextPart_000_0018_01C3E271.DDD65960--