Today's Message Index:
----------------------
1. 07:29 AM - Aileron mass balance (James Grieco)
2. 08:28 AM - Re: Aileron weight missing (FLYaDIVE)
3. 08:46 AM - Re: Aileron mass balance (FLYaDIVE)
4. 10:57 AM - Re: Aileron mass balance (Gary Vogt)
5. 10:59 AM - Re: Aileron weight missing (Gary Vogt)
6. 11:04 AM - Re: Aileron mass balance (Gary Vogt)
7. 01:32 PM - Re: Ground straps AA-5A (Hosler, John)
8. 01:42 PM - Re: Re: Ground straps AA-5A (flyv35b)
9. 01:52 PM - Re: Re: Ground straps AA-5A (Hosler, John)
10. 03:19 PM - Re: Re: Ground straps AA-5A (flyv35b)
Message 1
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| Subject: | Aileron mass balance |
I would like to have seen those pics. I did not catch the beginning of the story.
Did this AC crash? As I envision what you describe, it sounds like the aluminum
torque tube failed, not the welded steel? The moments would still balance
around the hinge line, so I don't think it would necessarily hit the stop.
Message 2
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| Subject: | Re: Aileron weight missing |
Hello James:
GREAT explanation.
The only exception to this would be that:
1 - If the plane is flying S&L the Weight would be inside the wing tip.
2 - The gust would have to be perpendicular to the bottom of the wing
going straight up.
3 - And would have to enter the weight hole without any difference in
pressure or speed when compared to the aileron the weight is attached to.
4 - Your explanation only accounts for One Wing & One Aileron... What about
all the counter forces created by the other wing & aileron? As one aileron
goes up the other is forced to go down.
But, YES, the force would be perpendicular to the torque tube and with a
huge amount of rust the bracket may fail. I have never seen a bracket that
bad... Rust - yes, worn bushings - yes, worn torque tube - yes, bent stops
- yes, incorrectly installed stops - yes and RUSTED counter balance weights
and mounting bolts - Most diffidently yes.
Barry
"Chop'd Liver"
On Sat, Jan 28, 2012 at 8:49 AM, James Grieco <jamesgrieco@yahoo.com> wrote:
> jamesgrieco@yahoo.com>
>
> I think there is a misconception about the weight. Its specific job is as
> a mass balance about the hinge line. If you draw a free body diagram of the
> aileron with the weight and a chord wise cut of the aileron, the two masses
> balance around the hinge bracket. When you apply a vertical gust, the
> inertia load on both sides of the hinge is the same, and in the same
> direction, so the hinge bracket gets wacked with combined load of the
> aileron mass + the counter weight mass X the vertical gust factor. This
> means the aileron wouldn't rotate, but there would be a large bending
> moment at the junction of the weight to tube welded joint. With rust and
> continuous fatigue loading it could break. Since no aileron rotation
> occurs, the rod would not hit the stop.
> An estimate of the Max load and rod stress seen can be found by
> determining the ultimate capability of the hinge bracket. Since I gather it
> did not fail, the bending moment applied to the rod would be 1/2 the
> bracket ultimate load capability X the length of the rod to the CG of the
> mass. The gust factor would be 1/2 the bracket ultimate load divided by the
> weight of the counter weight up to the weld.
>
>
Message 3
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| Subject: | Re: Aileron mass balance |
Gary:
Pictures would have added a lot to the FMA.
You mentioned that the torque tube was sheared? Not crushed or deformed.
Two thoughts come to mind:
1 - Where was the shear, was it inline with the torque tube bracket? As if
the bushing was cut through by friction and the friction was all around the
torque tube diameter?
2 - Was the bushing still there and if so, in what condition?
It is extremely difficult to shear a tubular object. I have never seen it
done without deforming the tube shape. It would be very easy to consider
the tube being worn through and the bushing missing. You can shear an 'I'
beam but not a tube.
My money would be on a highly worn or missing bushing. And then the
question becomes: Wasn't this ever checked during Annual?
Barry
On Sun, Jan 29, 2012 at 1:53 AM, Gary L Vogt <teamgrumman@yahoo.com> wrote:
> I appreciate the lessons in strength of materials and statics, but it's
> more than just a missing counterweight. I wish I'd taken pics. The end of
> the torque tube was sheared at the aileron bearing bracket. That degree of
> force has to be transferred to the aileron stop, if and only if, the bolt
> that does the stopping is still there.
>
> Gary
> Sent from my iPad
>
> On Jan 28, 2012, at 7:08 PM, Gary Vogt <teamgrumman@yahoo.com> wrote:
>
> OK, but, to get the weight into the slipstream far enough to get dragged
> on, it has to move past the stop. Otherwise, there would be a lot of torn
> off weights.
>
> ------------------------------
> *From:* James Grieco <jamesgrieco@yahoo.com>
> *To:* TeamGrumman <teamgrumman-list@matronics.com>
> *Sent:* Saturday, January 28, 2012 5:50 AM
> *Subject:* TeamGrumman-List: Aileron mass balance
>
> jamesgrieco@yahoo.com>
>
> I think there is a misconception about the weight. Its specific job is as
> a mass balance about the hinge line. If you draw a free body diagram of the
> aileron with the weight and a chord wise cut of the aileron, the two masses
> balance around the hinge bracket. When you apply a vertical gust, the
> inertia load on both sides of the hinge is the same, and in the same
> direction, so the hinge bracket gets wacked with combined load of the
> aileron mass + the counter weight mass X the vertical gust factor. This
> means the aileron wouldn't rotate, but there would be a large bending
> moment at the junction of the weight to tube welded joint. With rust and
> continuous fatigue loading it could break. Since no aileron rotation
> occurs, the rod would not hit the stop.
> An estimate of the Max load and rod stress seen can be found by
> determining the ultimate capability of the hinge bracket. Since I gather it
> did not fail, the bending moment applied to the rod would be 1/2 the
> bracket ultimate load capability X the length of the rod to the CG of the
> mass. The gust factor would be 1/2 the bracket ultimate load divided by the
> weight of the counter weight upamGrumman-List" target="_blank">
> http://www.matronics.com/Navigator?TeamGrumman-List
> <========================**
>
>
Message 4
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| Subject: | Re: Aileron mass balance |
Go out to your plane and move the aileron up and down. -The odds of anyth
ing tearing the counter weight off without touching the aileron stop would
be near infinity. -Had the bolt been there to hit the stop, when the pilo
t snapped the yoke back over to correct for the turbulence, he's have run o
ut of aileron authority.=0A=0AI got into some severe turbulence over Bakers
field . -The plane was instantly snapped to 90 bank. -It was all I coul
d do to keep from going over. -Correcting the bank with aileron was all I
had.=0A=0AI've done my share of inspections to say I've seen a far number
of bent aileron stops. -The bolts are there to stop the aileron from exce
eding its designed limit.=0A=0A=0A________________________________=0A From:
James Grieco <jamesgrieco@yahoo.com>=0ATo: teamgrumman-list@matronics.com
=0ASent: Sunday, January 29, 2012 7:27 AM=0ASubject: TeamGrumman-List: Aile
o <jamesgrieco@yahoo.com>=0A=0AI would like to have seen those pics. I did
not catch the beginning of the story. Did this AC crash? As I envision what
you describe,- it sounds like the aluminum torque tube failed,- not th
e welded steel? The moments would still balance around the hinge line, so I
===========
Message 5
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| Subject: | Re: Aileron weight missing |
Right, and the guy never added any inputs to the controls after the turbule
nce upset his attitude. -Go fly behind another plane in its wake and try
not to move the yoke. -It can't be done.=0A=0A"huge-amount-of rust th
e bracket may fail." - --- aluminum doesn't rust.=0A=0A=0A=0A____________
____________________=0A From: FLYaDIVE <flyadive@gmail.com>=0ATo: teamgrumm
an-list@matronics.com =0ASent: Sunday, January 29, 2012 8:25 AM=0ASubject:
Re: TeamGrumman-List: Aileron weight missing=0A =0A=0AHello James:=0A=0AGRE
AT explanation.=0A=0AThe only-exception-to this would be that:=0A1 - If
the plane is flying S&L the Weight would be inside the wing tip.=0A2 - The
gust would have to be perpendicular to the bottom of the wing going-stra
ight-up.=0A3 - And would have to enter the weight hole without any-diff
erence-in pressure or speed when-compared-to the aileron the weight i
s attached to.=0A4 - Your-explanation-only accounts for One Wing & One
Aileron... What about all the counter forces created by the other wing & ai
leron? As one aileron goes up the other is forced to go down. -=0A=0ABut,
YES, the force would be perpendicular to the torque tube and with a huge
-amount-of rust the bracket may fail. I have never seen a bracket that
bad... Rust - yes, worn bushings - yes, worn torque tube - yes, bent stops
- yes,-incorrectly-installed stops - yes and RUSTED counter-balance
-weights and mounting bolts - Most-diffidently-yes.=0A=0ABarry=0A"Cho
p'd Liver"=0A=0A=0A=0AOn Sat, Jan 28, 2012 at 8:49 AM, James Grieco <jamesg
Grieco <jamesgrieco@yahoo.com>=0A>=0A>I think there is a misconception abou
t the weight. Its specific job is as a mass balance about the hinge line. I
f you draw a free body diagram of the aileron with the weight and a chord w
ise cut of the aileron, the two masses balance around the hinge bracket. Wh
en you apply a vertical gust, the inertia load on both sides of the hinge i
s the same, and in the same direction, so the hinge bracket gets wacked wit
h combined load of the aileron mass + the counter weight mass X the vertica
l gust factor. This means the aileron wouldn't rotate, but there would be a
large bending moment at the junction of the weight to tube welded joint. W
ith rust and continuous fatigue loading it could break. Since no aileron ro
tation occurs, the rod would not hit the stop.=0A>An estimate of the Max lo
ad and rod stress seen can be found by determining the ultimate capability
of the hinge bracket. Since I gather it did not fail, -the bending moment
applied to the rod would be 1/2 the bracket ultimate load capability -X
the length of the rod to the CG of the mass. The gust factor would be 1/2 t
he bracket ultimate load divided by the weight of the counter weight up to
the weld.=0A>=0A>=0A>============0A>List" target="_
blank">http://www.matronics.com/Navigator?TeamGrumman-List=0A>====
========0A>http://forums.matronics.com=0A>======
======0A>le, List Admin.=0A>="_blank">http://www.matronics.com/
================
Message 6
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| Subject: | Re: Aileron mass balance |
to be honest, I don't recall. -All I know is that when I looked at the pl
ane, the damage was like the NTSB says with the exception of the entire end
of the torque tube gone. -I was only there for about 20 minutes before t
here were FAA and NTSB people all over. -No cell phone cameras then.=0A
=0A=0A________________________________=0A From: FLYaDIVE <flyadive@gmail.co
m>=0ATo: teamgrumman-list@matronics.com =0ASent: Sunday, January 29, 2012 8
:43 AM=0ASubject: Re: TeamGrumman-List: Aileron mass balance=0A =0A=0AGary:
=0A=0APictures would have added a lot to the FMA.=0AYou mentioned that the
torque tube was-sheared? -Not crushed or deformed.=0ATwo thoughts come
to mind:=0A1 - Where was the shear, was it inline with the torque tube brac
ket? -As if the bushing was cut through by friction and the friction was
all around the torque tube diameter?=0A2 - Was the bushing still there and
if so, in what condition?=0A=0AIt is-extremely-difficult-to shear a
-tubular-object. -I have never seen it done without deforming the tub
e shape. -It would be very easy to consider the tube being worn through a
nd the bushing missing. -You can shear an 'I' beam but not a tube. -=0A
My money would be on a highly worn or missing bushing. -And then the ques
tion becomes: -Wasn't this ever checked during Annual?=0A=0A=0ABarry=0A
=0A=0AOn Sun, Jan 29, 2012 at 1:53 AM, Gary L Vogt <teamgrumman@yahoo.com>
wrote:=0A=0AI appreciate the lessons in strength of materials and statics,
but it's more than just a missing counterweight. I wish I'd taken pics. The
end of the torque tube was sheared at the aileron bearing bracket. That de
gree of force has to be transferred to the aileron stop, if and only if, th
e bolt that does the stopping is still there.-=0A>=0A>=0A>GarySent from m
y iPad=0A>=0A>On Jan 28, 2012, at 7:08 PM, Gary Vogt <teamgrumman@yahoo.com
> wrote:=0A>=0A>=0A>OK, but, to get the weight into the slipstream far enou
gh to get dragged on, it has to move past the stop. -Otherwise, there wou
ld be a lot of torn off weights.=0A>>=0A>>=0A>>=0A>>_______________________
_________=0A>> From: James Grieco <jamesgrieco@yahoo.com>=0A>>To: TeamGrumm
an <teamgrumman-list@matronics.com> =0A>>Sent: Saturday, January 28, 2012 5
:50 AM=0A>>Subject: TeamGrumman-List: Aileron mass balance=0A>> =0A>>--> Te
amGrumman-List message posted by: James Grieco <jamesgrieco@yahoo.com>=0A>>
=0A>>I think there is a misconception about the weight. Its specific job is
as a mass balance about the hinge line. If you draw a free body diagram of
the aileron with the weight and a chord wise cut of the aileron, the two m
asses balance around the hinge bracket. When you apply a vertical gust, the
inertia load on both sides of the hinge is the same, and in the same direc
tion, so the hinge bracket gets wacked with combined load of the aileron ma
ss + the counter weight mass X the vertical gust factor. This means the ail
eron wouldn't rotate, but there would be a large bending moment at the junc
tion of the weight to tube welded joint. With rust and continuous fatigue l
oading it could break. Since no aileron rotation occurs, the rod would not
hit the stop. =0A>>An estimate of the Max load=0A and rod stress seen can b
e found by determining the ultimate capability of the hinge bracket. Since
I gather it did not fail,- the bending moment applied to the rod would be
1/2 the bracket ultimate load capability- X the length of the rod to the
CG of the mass. The gust factor would be 1/2 the bracket ultimate load div
ided by the weight of the counter weight upamGrumman-List"=0A target="_bl
ank">http://www.matronics.com/Navigator?TeamGrumman-List<======
===================0A>>=0A>>=0A>>=0A=0A
==================
Message 7
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| Subject: | RE: Ground straps AA-5A |
I have been having significant static on the radio when flying in rain.
I suspect static charge build up on rudder (I can hear the rudder strobe
in the static).
I cannot find a ground strap connecting the rudder to the vertical stab
or fuselage.
A ground strap is mentioned in the maintenance manual (part of rudder
removal procedure).
Can someone tell me where this ground strap is supposed to be located??
Thanks!
John
704-252-0780
From: owner-teamgrumman-list-server@matronics.com
[mailto:owner-teamgrumman-list-server@matronics.com] On Behalf Of Gary
Vogt
Sent: Sunday, January 29, 2012 2:02 PM
Subject: Ground straps AA-5A
to be honest, I don't recall. All I know is that when I looked at the
plane, the damage was like the NTSB says with the exception of the
entire end of the torque tube gone. I was only there for about 20
minutes before there were FAA and NTSB people all over. No cell phone
cameras then.
________________________________
From: FLYaDIVE <flyadive@gmail.com>
Sent: Sunday, January 29, 2012 8:43 AM
Subject: Re: TeamGrumman-List: Aileron mass balance
Gary:
Pictures would have added a lot to the FMA.
You mentioned that the torque tube was sheared? Not crushed or
deformed.
Two thoughts come to mind:
1 - Where was the shear, was it inline with the torque tube bracket? As
if the bushing was cut through by friction and the friction was all
around the torque tube diameter?
2 - Was the bushing still there and if so, in what condition?
It is extremely difficult to shear a tubular object. I have never seen
it done without deforming the tube shape. It would be very easy to
consider the tube being worn through and the bushing missing. You can
shear an 'I' beam but not a tube.
My money would be on a highly worn or missing bushing. And then the
question becomes: Wasn't this ever checked during Annual?
Barry
On Sun, Jan 29, 2012 at 1:53 AM, Gary L Vogt <teamgrumman@yahoo.com>
wrote:
I appreciate the lessons in strength of materials and statics, but it's
more than just a missing counterweight. I wish I'd taken pics. The end
of the torque tube was sheared at the aileron bearing bracket. That
degree of force has to be transferred to the aileron stop, if and only
if, the bolt that does the stopping is still there.
Gary
Sent from my iPad
On Jan 28, 2012, at 7:08 PM, Gary Vogt <teamgrumman@yahoo.com> wrote:
OK, but, to get the weight into the slipstream far enough to get
dragged on, it has to move past the stop. Otherwise, there would be a
lot of torn off weights.
________________________________
From: James Grieco <jamesgrieco@yahoo.com>
To: TeamGrumman <teamgrumman-list@matronics.com>
Sent: Saturday, January 28, 2012 5:50 AM
Subject: TeamGrumman-List: Aileron mass balance
<jamesgrieco@yahoo.com>
I think there is a misconception about the weight. Its specific
job is as a mass balance about the hinge line. If you draw a free body
diagram of the aileron with the weight and a chord wise cut of the
aileron, the two masses balance around the hinge bracket. When you apply
a vertical gust, the inertia load on both sides of the hinge is the
same, and in the same direction, so the hinge bracket gets wacked with
combined load of the aileron mass + the counter weight mass X the
vertical gust factor. This means the aileron wouldn't rotate, but there
would be a large bending moment at the junction of the weight to tube
welded joint. With rust and continuous fatigue loading it could break.
Since no aileron rotation occurs, the rod would not hit the stop.
An estimate of the Max load and rod stress seen can be found by
determining the ultimate capability of the hinge bracket. Since I gather
it did not fail, the bending moment applied to the rod would be 1/2 the
bracket ultimate load capability X the length of the rod to the CG of
the mass. The gust factor would be 1/2 the bracket ultimate load divided
by the weight of the counter weight upamGrumman-List"
target="_blank">http://www.matronics.com/Navigator?TeamGrumman-List<=
==
===================
-========================
Message 8
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| Subject: | Re: RE: Ground straps AA-5A |
On 1/29/2012 1:29 PM, Hosler, John wrote:
> I have been having significant static on the radio when flying in rain.
> I suspect static charge build up on rudder (I can hear the rudder strobe
> in the static).
>
> I cannot find a ground strap connecting the rudder to the vertical stab
> or fuselage.
>
> A ground strap is mentioned in the maintenance manual (part of rudder
> removal procedure).
>
> Can someone tell me where this ground strap is supposed to be located??
>
> Thanks!
>
> John
It's about 10in. or so above the bottom rudder bearing, on the very
front of the rudder. Turn the rudder to the stop using TWO hands and
you might see it.
Cliff
Message 9
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| Subject: | RE: Ground straps AA-5A |
Great thanks!
Sounds like replacement will require removal of the rudder.
John
-----Original Message-----
From: owner-teamgrumman-list-server@matronics.com
[mailto:owner-teamgrumman-list-server@matronics.com] On Behalf Of
flyv35b
Sent: Sunday, January 29, 2012 4:41 PM
Subject: Re: TeamGrumman-List: RE: Ground straps AA-5A
On 1/29/2012 1:29 PM, Hosler, John wrote:
> I have been having significant static on the radio when flying in
rain.
> I suspect static charge build up on rudder (I can hear the rudder
strobe
> in the static).
>
> I cannot find a ground strap connecting the rudder to the vertical
stab
> or fuselage.
>
> A ground strap is mentioned in the maintenance manual (part of rudder
> removal procedure).
>
> Can someone tell me where this ground strap is supposed to be
located??
>
> Thanks!
>
> John
It's about 10in. or so above the bottom rudder bearing, on the very
front of the rudder. Turn the rudder to the stop using TWO hands and
you might see it.
Cliff
Message 10
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| Subject: | Re: RE: Ground straps AA-5A |
On 1/29/2012 1:49 PM, Hosler, John wrote:
> --> TeamGrumman-List message posted by: "Hosler, John"<JHOSLER@epri.com>
>
> Great thanks!
>
> Sounds like replacement will require removal of the rudder.
>
> John
Not totally. The beacon wire will prevent you from totally removing it
and you don't want to fish that out and back in. Remove the rudder
cables by first cutting 3/4" thick blocks of wood and wedging behind the
copilot pedals to bring them aft until there is slack in the cables.
The you can remove the two flat head screws that hold the top bearing
mounting plate and then raise the rudder up out of the bottom bearing so
you can rotate it and get at the rivet and ground strap. It can hang on
the top plate and wire it to the vertical fin if you are careful. Might
as well go ahead and replace the lower rudder bearing while you have it off.
Cliff
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