Flight characteristics questions


q2fun
 

Hi All,

I have some questions about the flight characteristics of the Q-2.
Pitch sensitivity. With an after c/g my Q2 seams pitch sensitive.
My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
normal to get more pitch sensitive the more aft the C/G gets?

Rudder to control bank. My rudder does not do anything for bank.
If the wing is down 5 degrees and you use the rudder to bring it up,
all that happens is the plane will yaw and the bank may even get
steeper. Is that a normal characteristic of the Q design?

With an increase in airspeed above 150 mph indicated the airplane
wants to pitch down and farther increase airspeed/pitch down
harder. Is this normal? Sparrow strainers to small for this
airspeed? I have the standard pitch trim system.

I have been flying my Q since April and now have 62 hours in it. It
is a joy to blast around the pattern and it is even a joy to put gas
in it after a long cross county. It is just a little too slow in
cruise 130 kts.

Thank You All.
Tim Bryant
KUNV
N86TB


Sam Hoskins <shoskins@...>
 

1. I think pitch sensitivity is normal, especially with aft CG and at high
(8,000+ft) altitude.

2. My plane does the same. The rudder doesn't control bank, the ailerons
do.

2. This sounds a little odd. Maybe the sparrow strainers are too big or
have too steep of an angle. It could also be that your canard needs to be
adjusted up a degree or so. Maybe try installing adjustable sparrow
strainers first. That would be an easy experiment.

Sam Hoskins Q-200 1,600+ hrs.

Murphysboro, IL



_____

From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com] On Behalf Of
q2fun
Sent: Monday, October 16, 2006 6:28 PM
To: Q-LIST@yahoogroups.com
Subject: [Q-LIST] Flight characteristics questions



Hi All,

I have some questions about the flight characteristics of the Q-2.
Pitch sensitivity. With an after c/g my Q2 seams pitch sensitive.
My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
normal to get more pitch sensitive the more aft the C/G gets?

Rudder to control bank. My rudder does not do anything for bank.
If the wing is down 5 degrees and you use the rudder to bring it up,
all that happens is the plane will yaw and the bank may even get
steeper. Is that a normal characteristic of the Q design?

With an increase in airspeed above 150 mph indicated the airplane
wants to pitch down and farther increase airspeed/pitch down
harder. Is this normal? Sparrow strainers to small for this
airspeed? I have the standard pitch trim system.

I have been flying my Q since April and now have 62 hours in it. It
is a joy to blast around the pattern and it is even a joy to put gas
in it after a long cross county. It is just a little too slow in
cruise 130 kts.

Thank You All.
Tim Bryant
KUNV
N86TB


Jim Patillo
 

TIM, FIRST CONGRATULATIONS ON YOUR 62 HOURS FLIGHT TIME IN A Q.
YOU'VE JOINED A UNIQUE CLUB.

--- In Q-LIST@yahoogroups.com, "q2fun" <q2fun@...> wrote:

Hi All,

I have some questions about the flight characteristics of the Q-
2.
Pitch sensitivity. With an after c/g my Q2 seams pitch
sensitive.
My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
normal to get more pitch sensitive the more aft the C/G gets?
ABSOLUTELY! FAR AFT CG IS NOT A GOOD PLACE TO BE IN THIS PLANE.

Rudder to control bank. My rudder does not do anything for bank.
If the wing is down 5 degrees and you use the rudder to bring it
up,
all that happens is the plane will yaw and the bank may even get
steeper. Is that a normal characteristic of the Q design?
MAYBE. IN LEVEL FLIGHT, PUSHING THE RUDDER WILL DEFINATELY YAW THE
TAIL BUT I HAVEN'T NOTICE THE BANK INCREASING. IN SLIGHT BANKS MINE
WILL RECOVER USING THE RUDDER ONLY. I THINK THE SMALL RUDDER ON
THESE PLANES DOES A GOOD JOB BUT RECOVERING FROM A BANK SOLELY USING
RUDDER .......NOT SO GOOD. I WILL CHECK IT OUT WHEN I FLY AGAIN.

With an increase in airspeed above 150 mph indicated the airplane
wants to pitch down and farther increase airspeed/pitch down
harder. Is this normal? Sparrow strainers to small for this
airspeed? I have the standard pitch trim system.
I CRUISED MY Q200 (LS1)SATURDAY FROM 130 TO 185K AND DID NOT NOTICE
ANY TUCKING OR PITCHING. I ALSO HAVE A STANDARD TRIM SYSTEM. MAYBE
YOUR STRAINERS ARE INSTALLED INCORRECT.

I have been flying my Q since April and now have 62 hours in it.
It
is a joy to blast around the pattern and it is even a joy to put
gas
in it after a long cross county. It is just a little too slow in
cruise 130 kts.
YOU CAN FIX THAT! TIM WE SEE 160-165K CRUISE STANDARD WITH PUMPED
0200'S (TAIL DRAGGER VERSION). JUST COSTS A LITTLE $$$$$$$.

REGARDS,
JIM PATILLO

Thank You All.
Tim Bryant
KUNV
N86TB


David J. Gall
 

Sam,

I think you're thinking backwards here. The described behavior indicates
sparrow strainers that are too small, not too large; or not angled enough
(trailing edge up) instead of too steeply.

Without sparrow strainers, when the airplane inadvertently goes faster than
its trimmed airspeed, the slight undercamber of the LS(1) elevator causes
aerodynamic force that pushes the trailing edge of the elevator up. This
lets the airplane's nose come down and allows the airplane to accelerate to
a yet-higher speed. NOT GOOD!

The sole purpose of sparrow strainers is to REVERSE this pattern. When the
nose inadvertently drops and the speed builds, the sparrow strainers should
push the trailing edge of the elevator down so as to raise the nose of the
airplane, thus slowing it back down. Conversely, when the airplane slows
down (due to an inadvertent climb) the decreasing dynamic pressure on the
sparrow strainers lets them allow the trailing edge of the elevators to come
up (usually in response to a down-spring in the trim system), lowering the
nose and restoring the airplane to it's original airspeed.

This is speed stability. It is closely associated with pitch stability, but
is not the same thing. Burt Rutan devoted several issues of his Canard
Pusher newsletter to describing it, discussing it, and reporting on the
requirements for it in his several homebuilders' designs.

Another clue to incorrect speed stability is light or "sensitive" pitch
control, as reported in Mr. Q2fun's item #1. True, pitch sensitivity is also
a function of CG position, but given two otherwise identical airplanes with
the same CG location, the one with greater speed stability will have
less-sensitive pitch feel. That's because the greater aerodynamic forces of
the larger or more effective (larger/correct deflection angle) sparrow
strainers will cause the elevator stick force to be greater for any given
deflection of the elevators away from their trim position. It's kind of like
using a larger paddle on a canoe, you just have to pull harder to get it to
move through the water.

A more effective sparrow strainer will also need to be met with greater
tension in the pitch down-spring of the spring-type pitch trim system at
higher airspeeds. If the down spring of the trim system is only lightly
loaded at cruise speed or if the up-spring is loaded and the down spring is
slack at cruise speed (heaven forbid!) then there is a real problem and a
potentially dangerous situation.

What happens if the up-spring is loaded at cruise? If the nose drops, the
aerodynamic forces get stronger while the spring force stays the same, so
the aerodynamic forces "win." The up-spring was resisting the aero forces
that want to make the airplane dive, but those forces now win and the
airplane dives. Conversely, if the down-spring is loaded at cruise, then a
nose drop again means larger aero forces, but those forces (from the sparrow
strainers) act to RAISE the nose, not lower it further. Raising the nose
restores the airplane to level flight.

Rutan advised his builders that his airplane designs should be
AERODYNAMICALLY trimmed to a low-cruise airspeed when flown hands-off and
with the pitch trim system disconnected. His rationale is that if a crucial
part or connection in the pitch control system should fail thereby leaving
an elevator completely disconnected from the trim system and the control
system, it does not automatically kill the pilot. I do NOT advise
disconnecting the trim system in a Q2 or Q200 or even a Quickie because of
the risks involved, but you can certainly look at your trim springs and
simulate a disconnect by moving the trim control to make them as equally
slack as possible. By this method one might be able to get a relative idea
of what the sparrow strainers are doing and what the airplane's aerodynamic
trim speed is.

In summary, I think there is a dangerous situation being described by Mr.
Q2fun and I hope he gets his sparrow strainers and trim system looked at by
one of the "old heads" on this list to see if it is rigged right or if
there's something amiss. I'll wager that the up-spring is doing a lot of
work at cruise speeds and just loses the battle against aero forces at
speeds above 150 mph. Not good -- not safe!

Just my worry-wart two cents worth,


David J. Gall
BSAE
Sacramento, CA

-----Original Message-----
From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of Sam Hoskins
Sent: Monday, October 16, 2006 5:02 PM
To: Q-LIST@yahoogroups.com
Subject: RE: [Q-LIST] Flight characteristics questions

1. I think pitch sensitivity is normal, especially with aft
CG and at high
(8,000+ft) altitude.

2. My plane does the same. The rudder doesn't control bank,
the ailerons do.

2. This sounds a little odd. Maybe the sparrow strainers
are too big or have too steep of an angle. It could also be
that your canard needs to be adjusted up a degree or so.
Maybe try installing adjustable sparrow strainers first.
That would be an easy experiment.

Sam Hoskins Q-200 1,600+ hrs.

Murphysboro, IL



_____

From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of q2fun
Sent: Monday, October 16, 2006 6:28 PM
To: Q-LIST@yahoogroups.com
Subject: [Q-LIST] Flight characteristics questions



Hi All,

I have some questions about the flight characteristics of the Q-2.
Pitch sensitivity. With an after c/g my Q2 seams pitch sensitive.
My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
normal to get more pitch sensitive the more aft the C/G gets?

Rudder to control bank. My rudder does not do anything for bank.
If the wing is down 5 degrees and you use the rudder to bring
it up, all that happens is the plane will yaw and the bank
may even get steeper. Is that a normal characteristic of the
Q design?

With an increase in airspeed above 150 mph indicated the
airplane wants to pitch down and farther increase
airspeed/pitch down harder. Is this normal? Sparrow strainers
to small for this airspeed? I have the standard pitch trim system.

I have been flying my Q since April and now have 62 hours in
it. It is a joy to blast around the pattern and it is even a
joy to put gas in it after a long cross county. It is just a
little too slow in cruise 130 kts.

Thank You All.
Tim Bryant
KUNV
N86TB









Quickie Builders Association WEB site
http://www.quickiebuilders.org


Yahoo! Groups Links





michel & hélène moreau
 

David,

Does this apply to GU as well as LS1? I don't see a "slight undercamber" on my GU elevator.
Thanks for such a clear explanation of the phenomenon.

MM

----- Original Message -----
From: "David J. Gall" <David@Gall.com>
To: <Q-LIST@yahoogroups.com>
Sent: Tuesday, October 17, 2006 5:42 AM
Subject: RE: [Q-LIST] Flight characteristics questions


Sam,

I think you're thinking backwards here. The described behavior indicates
sparrow strainers that are too small, not too large; or not angled enough
(trailing edge up) instead of too steeply.

Without sparrow strainers, when the airplane inadvertently goes faster than
its trimmed airspeed, the slight undercamber of the LS(1) elevator causes
aerodynamic force that pushes the trailing edge of the elevator up. This
lets the airplane's nose come down and allows the airplane to accelerate to
a yet-higher speed. NOT GOOD!

The sole purpose of sparrow strainers is to REVERSE this pattern. When the
nose inadvertently drops and the speed builds, the sparrow strainers should
push the trailing edge of the elevator down so as to raise the nose of the
airplane, thus slowing it back down. Conversely, when the airplane slows
down (due to an inadvertent climb) the decreasing dynamic pressure on the
sparrow strainers lets them allow the trailing edge of the elevators to come
up (usually in response to a down-spring in the trim system), lowering the
nose and restoring the airplane to it's original airspeed.

This is speed stability. It is closely associated with pitch stability, but
is not the same thing. Burt Rutan devoted several issues of his Canard
Pusher newsletter to describing it, discussing it, and reporting on the
requirements for it in his several homebuilders' designs.

Another clue to incorrect speed stability is light or "sensitive" pitch
control, as reported in Mr. Q2fun's item #1. True, pitch sensitivity is also
a function of CG position, but given two otherwise identical airplanes with
the same CG location, the one with greater speed stability will have
less-sensitive pitch feel. That's because the greater aerodynamic forces of
the larger or more effective (larger/correct deflection angle) sparrow
strainers will cause the elevator stick force to be greater for any given
deflection of the elevators away from their trim position. It's kind of like
using a larger paddle on a canoe, you just have to pull harder to get it to
move through the water.

A more effective sparrow strainer will also need to be met with greater
tension in the pitch down-spring of the spring-type pitch trim system at
higher airspeeds. If the down spring of the trim system is only lightly
loaded at cruise speed or if the up-spring is loaded and the down spring is
slack at cruise speed (heaven forbid!) then there is a real problem and a
potentially dangerous situation.

What happens if the up-spring is loaded at cruise? If the nose drops, the
aerodynamic forces get stronger while the spring force stays the same, so
the aerodynamic forces "win." The up-spring was resisting the aero forces
that want to make the airplane dive, but those forces now win and the
airplane dives. Conversely, if the down-spring is loaded at cruise, then a
nose drop again means larger aero forces, but those forces (from the sparrow
strainers) act to RAISE the nose, not lower it further. Raising the nose
restores the airplane to level flight.

Rutan advised his builders that his airplane designs should be
AERODYNAMICALLY trimmed to a low-cruise airspeed when flown hands-off and
with the pitch trim system disconnected. His rationale is that if a crucial
part or connection in the pitch control system should fail thereby leaving
an elevator completely disconnected from the trim system and the control
system, it does not automatically kill the pilot. I do NOT advise
disconnecting the trim system in a Q2 or Q200 or even a Quickie because of
the risks involved, but you can certainly look at your trim springs and
simulate a disconnect by moving the trim control to make them as equally
slack as possible. By this method one might be able to get a relative idea
of what the sparrow strainers are doing and what the airplane's aerodynamic
trim speed is.

In summary, I think there is a dangerous situation being described by Mr.
Q2fun and I hope he gets his sparrow strainers and trim system looked at by
one of the "old heads" on this list to see if it is rigged right or if
there's something amiss. I'll wager that the up-spring is doing a lot of
work at cruise speeds and just loses the battle against aero forces at
speeds above 150 mph. Not good -- not safe!

Just my worry-wart two cents worth,


David J. Gall
BSAE
Sacramento, CA

-----Original Message-----
From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of Sam Hoskins
Sent: Monday, October 16, 2006 5:02 PM
To: Q-LIST@yahoogroups.com
Subject: RE: [Q-LIST] Flight characteristics questions

1. I think pitch sensitivity is normal, especially with aft
CG and at high
(8,000+ft) altitude.

2. My plane does the same. The rudder doesn't control bank,
the ailerons do.

2. This sounds a little odd. Maybe the sparrow strainers
are too big or have too steep of an angle. It could also be
that your canard needs to be adjusted up a degree or so.
Maybe try installing adjustable sparrow strainers first.
That would be an easy experiment.

Sam Hoskins Q-200 1,600+ hrs.

Murphysboro, IL



_____

From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of q2fun
Sent: Monday, October 16, 2006 6:28 PM
To: Q-LIST@yahoogroups.com
Subject: [Q-LIST] Flight characteristics questions



Hi All,

I have some questions about the flight characteristics of the Q-2.
Pitch sensitivity. With an after c/g my Q2 seams pitch sensitive.
My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
normal to get more pitch sensitive the more aft the C/G gets?

Rudder to control bank. My rudder does not do anything for bank.
If the wing is down 5 degrees and you use the rudder to bring
it up, all that happens is the plane will yaw and the bank
may even get steeper. Is that a normal characteristic of the
Q design?

With an increase in airspeed above 150 mph indicated the
airplane wants to pitch down and farther increase
airspeed/pitch down harder. Is this normal? Sparrow strainers
to small for this airspeed? I have the standard pitch trim system.

I have been flying my Q since April and now have 62 hours in
it. It is a joy to blast around the pattern and it is even a
joy to put gas in it after a long cross county. It is just a
little too slow in cruise 130 kts.

Thank You All.
Tim Bryant
KUNV
N86TB








Quickie Builders Association WEB site
http://www.quickiebuilders.org


Yahoo! Groups Links






Quickie Builders Association WEB site
http://www.quickiebuilders.org


Yahoo! Groups Links




David J. Gall
 

Michel,

Yes.

There is no undercamber on the GU elevator so the aero forces involved are
not large. However, the system does rely on the up-spring to hold the
trailing edge of the elevetor down in flight.

Early on in the pages of QuickTalk there were a couple of reports of trim
system failures ("modified hackwaw blade" failures) in the original Quickie.
The ensuing requirement for holding continuous back pressure was reported,
as well as the fatigue level of doing so for as little as ten minutes. (I'm
not going to look up the exact issue number.)

I'm not planning to re-engineer or suggest that anyone else re-engineer the
system on the GU canard, but be aware that it is a potential problem.

IF<< I were to reengineer the system, I think I'd merely "reflex" the
trailing edge of the elevator ever so slightly, as John Roncz did for the
Roncz 1145MS replacement canard airfoil for the Long-EZ.

IF<< I thought it was a problem of sufficient magnitude and was trying to
retrofit the existing GU elevator, I think I'd add sparrow strainers, though
they would not need to be angled nearly so severely as on the LS(1)
elevator. Of course, exact size and placement aft of the trailing edge would
be a matter of trial and error, and balancing the elevators against flutter
with the additional mass of the sparrow strainers aft of the hinge line is
an additional concern.

Like I said, I'm not planning to re-engineer or suggest that anyone else
re-engineer the system on the GU canard, but be aware that it is a potential
problem in the event of a control system and/or trim system mechanical
failure.


David J. Gall

-----Original Message-----
From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of Michel Moreau
Sent: Tuesday, October 17, 2006 7:43 AM
To: Q-LIST@yahoogroups.com
Subject: Re: [Q-LIST] Flight characteristics questions

David,

Does this apply to GU as well as LS1? I don't see a "slight
undercamber" on my GU elevator.
Thanks for such a clear explanation of the phenomenon.

MM

----- Original Message -----
From: "David J. Gall" <David@Gall.com>
To: <Q-LIST@yahoogroups.com>
Sent: Tuesday, October 17, 2006 5:42 AM
Subject: RE: [Q-LIST] Flight characteristics questions


Sam,

I think you're thinking backwards here. The described
behavior indicates
sparrow strainers that are too small, not too large; or not
angled enough
(trailing edge up) instead of too steeply.

Without sparrow strainers, when the airplane inadvertently
goes faster
than
its trimmed airspeed, the slight undercamber of the LS(1)
elevator causes
aerodynamic force that pushes the trailing edge of the
elevator up. This
lets the airplane's nose come down and allows the airplane
to accelerate
to
a yet-higher speed. NOT GOOD!

The sole purpose of sparrow strainers is to REVERSE this
pattern. When the
nose inadvertently drops and the speed builds, the sparrow
strainers
should
push the trailing edge of the elevator down so as to raise
the nose of the
airplane, thus slowing it back down. Conversely, when the
airplane slows
down (due to an inadvertent climb) the decreasing dynamic
pressure on the
sparrow strainers lets them allow the trailing edge of the
elevators to
come
up (usually in response to a down-spring in the trim
system), lowering the
nose and restoring the airplane to it's original airspeed.

This is speed stability. It is closely associated with
pitch stability,
but
is not the same thing. Burt Rutan devoted several issues of
his Canard
Pusher newsletter to describing it, discussing it, and
reporting on the
requirements for it in his several homebuilders' designs.

Another clue to incorrect speed stability is light or
"sensitive" pitch
control, as reported in Mr. Q2fun's item #1. True, pitch
sensitivity is
also
a function of CG position, but given two otherwise
identical airplanes
with
the same CG location, the one with greater speed stability will have
less-sensitive pitch feel. That's because the greater
aerodynamic forces
of
the larger or more effective (larger/correct deflection
angle) sparrow
strainers will cause the elevator stick force to be greater
for any given
deflection of the elevators away from their trim position.
It's kind of
like
using a larger paddle on a canoe, you just have to pull
harder to get it
to
move through the water.

A more effective sparrow strainer will also need to be met
with greater
tension in the pitch down-spring of the spring-type pitch
trim system at
higher airspeeds. If the down spring of the trim system is
only lightly
loaded at cruise speed or if the up-spring is loaded and
the down spring
is
slack at cruise speed (heaven forbid!) then there is a real
problem and a
potentially dangerous situation.

What happens if the up-spring is loaded at cruise? If the
nose drops, the
aerodynamic forces get stronger while the spring force
stays the same, so
the aerodynamic forces "win." The up-spring was resisting
the aero forces
that want to make the airplane dive, but those forces now
win and the
airplane dives. Conversely, if the down-spring is loaded at
cruise, then a
nose drop again means larger aero forces, but those forces
(from the
sparrow
strainers) act to RAISE the nose, not lower it further.
Raising the nose
restores the airplane to level flight.

Rutan advised his builders that his airplane designs should be
AERODYNAMICALLY trimmed to a low-cruise airspeed when flown
hands-off and
with the pitch trim system disconnected. His rationale is that if a
crucial
part or connection in the pitch control system should fail
thereby leaving
an elevator completely disconnected from the trim system
and the control
system, it does not automatically kill the pilot. I do NOT advise
disconnecting the trim system in a Q2 or Q200 or even a
Quickie because of
the risks involved, but you can certainly look at your trim
springs and
simulate a disconnect by moving the trim control to make
them as equally
slack as possible. By this method one might be able to get
a relative idea
of what the sparrow strainers are doing and what the airplane's
aerodynamic
trim speed is.

In summary, I think there is a dangerous situation being
described by Mr.
Q2fun and I hope he gets his sparrow strainers and trim
system looked at
by
one of the "old heads" on this list to see if it is rigged
right or if
there's something amiss. I'll wager that the up-spring is
doing a lot of
work at cruise speeds and just loses the battle against
aero forces at
speeds above 150 mph. Not good -- not safe!

Just my worry-wart two cents worth,


David J. Gall
BSAE
Sacramento, CA

-----Original Message-----
From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of Sam Hoskins
Sent: Monday, October 16, 2006 5:02 PM
To: Q-LIST@yahoogroups.com
Subject: RE: [Q-LIST] Flight characteristics questions

1. I think pitch sensitivity is normal, especially with aft
CG and at high
(8,000+ft) altitude.

2. My plane does the same. The rudder doesn't control bank,
the ailerons do.

2. This sounds a little odd. Maybe the sparrow strainers
are too big or have too steep of an angle. It could also be
that your canard needs to be adjusted up a degree or so.
Maybe try installing adjustable sparrow strainers first.
That would be an easy experiment.

Sam Hoskins Q-200 1,600+ hrs.

Murphysboro, IL



_____

From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of q2fun
Sent: Monday, October 16, 2006 6:28 PM
To: Q-LIST@yahoogroups.com
Subject: [Q-LIST] Flight characteristics questions



Hi All,

I have some questions about the flight characteristics of the Q-2.
Pitch sensitivity. With an after c/g my Q2 seams pitch sensitive.
My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
normal to get more pitch sensitive the more aft the C/G gets?

Rudder to control bank. My rudder does not do anything for bank.
If the wing is down 5 degrees and you use the rudder to bring
it up, all that happens is the plane will yaw and the bank
may even get steeper. Is that a normal characteristic of the
Q design?

With an increase in airspeed above 150 mph indicated the
airplane wants to pitch down and farther increase
airspeed/pitch down harder. Is this normal? Sparrow strainers
to small for this airspeed? I have the standard pitch trim system.

I have been flying my Q since April and now have 62 hours in
it. It is a joy to blast around the pattern and it is even a
joy to put gas in it after a long cross county. It is just a
little too slow in cruise 130 kts.

Thank You All.
Tim Bryant
KUNV
N86TB


Paul Buckley
 

Dave

As a matter of interest, an old method of achieving trim was to 'dope' a length of string along the airfoil trailing edge, varying the length to achieve the desired effect.
Do you think that this method could be used underneath the GU elevators as an alternative to camber, if only as a temporary explorative measure?

Paul Buckley
Cheshire
England

----- Original Message -----
From: David J. Gall
To: Q-LIST@yahoogroups.com
Sent: Tuesday, October 17, 2006 6:22 PM
Subject: RE: [Q-LIST] Flight characteristics questions


Michel,

Yes.

There is no undercamber on the GU elevator so the aero forces involved are
not large. However, the system does rely on the up-spring to hold the
trailing edge of the elevetor down in flight.

Early on in the pages of QuickTalk there were a couple of reports of trim
system failures ("modified hackwaw blade" failures) in the original Quickie.
The ensuing requirement for holding continuous back pressure was reported,
as well as the fatigue level of doing so for as little as ten minutes. (I'm
not going to look up the exact issue number.)

I'm not planning to re-engineer or suggest that anyone else re-engineer the
system on the GU canard, but be aware that it is a potential problem.

>>IF<< I were to reengineer the system, I think I'd merely "reflex" the
trailing edge of the elevator ever so slightly, as John Roncz did for the
Roncz 1145MS replacement canard airfoil for the Long-EZ.

>>IF<< I thought it was a problem of sufficient magnitude and was trying to
retrofit the existing GU elevator, I think I'd add sparrow strainers, though
they would not need to be angled nearly so severely as on the LS(1)
elevator. Of course, exact size and placement aft of the trailing edge would
be a matter of trial and error, and balancing the elevators against flutter
with the additional mass of the sparrow strainers aft of the hinge line is
an additional concern.

Like I said, I'm not planning to re-engineer or suggest that anyone else
re-engineer the system on the GU canard, but be aware that it is a potential
problem in the event of a control system and/or trim system mechanical
failure.

David J. Gall

> -----Original Message-----
> From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
> On Behalf Of Michel Moreau
> Sent: Tuesday, October 17, 2006 7:43 AM
> To: Q-LIST@yahoogroups.com
> Subject: Re: [Q-LIST] Flight characteristics questions
>
> David,
>
> Does this apply to GU as well as LS1? I don't see a "slight
> undercamber" on my GU elevator.
> Thanks for such a clear explanation of the phenomenon.
>
> MM
>
> ----- Original Message -----
> From: "David J. Gall" <David@Gall.com>
> To: <Q-LIST@yahoogroups.com>
> Sent: Tuesday, October 17, 2006 5:42 AM
> Subject: RE: [Q-LIST] Flight characteristics questions
>
>
> > Sam,
> >
> > I think you're thinking backwards here. The described
> behavior indicates
> > sparrow strainers that are too small, not too large; or not
> angled enough
> > (trailing edge up) instead of too steeply.
> >
> > Without sparrow strainers, when the airplane inadvertently
> goes faster
> > than
> > its trimmed airspeed, the slight undercamber of the LS(1)
> elevator causes
> > aerodynamic force that pushes the trailing edge of the
> elevator up. This
> > lets the airplane's nose come down and allows the airplane
> to accelerate
> > to
> > a yet-higher speed. NOT GOOD!
> >
> > The sole purpose of sparrow strainers is to REVERSE this
> pattern. When the
> > nose inadvertently drops and the speed builds, the sparrow
> strainers
> > should
> > push the trailing edge of the elevator down so as to raise
> the nose of the
> > airplane, thus slowing it back down. Conversely, when the
> airplane slows
> > down (due to an inadvertent climb) the decreasing dynamic
> pressure on the
> > sparrow strainers lets them allow the trailing edge of the
> elevators to
> > come
> > up (usually in response to a down-spring in the trim
> system), lowering the
> > nose and restoring the airplane to it's original airspeed.
> >
> > This is speed stability. It is closely associated with
> pitch stability,
> > but
> > is not the same thing. Burt Rutan devoted several issues of
> his Canard
> > Pusher newsletter to describing it, discussing it, and
> reporting on the
> > requirements for it in his several homebuilders' designs.
> >
> > Another clue to incorrect speed stability is light or
> "sensitive" pitch
> > control, as reported in Mr. Q2fun's item #1. True, pitch
> sensitivity is
> > also
> > a function of CG position, but given two otherwise
> identical airplanes
> > with
> > the same CG location, the one with greater speed stability will have
> > less-sensitive pitch feel. That's because the greater
> aerodynamic forces
> > of
> > the larger or more effective (larger/correct deflection
> angle) sparrow
> > strainers will cause the elevator stick force to be greater
> for any given
> > deflection of the elevators away from their trim position.
> It's kind of
> > like
> > using a larger paddle on a canoe, you just have to pull
> harder to get it
> > to
> > move through the water.
> >
> > A more effective sparrow strainer will also need to be met
> with greater
> > tension in the pitch down-spring of the spring-type pitch
> trim system at
> > higher airspeeds. If the down spring of the trim system is
> only lightly
> > loaded at cruise speed or if the up-spring is loaded and
> the down spring
> > is
> > slack at cruise speed (heaven forbid!) then there is a real
> problem and a
> > potentially dangerous situation.
> >
> > What happens if the up-spring is loaded at cruise? If the
> nose drops, the
> > aerodynamic forces get stronger while the spring force
> stays the same, so
> > the aerodynamic forces "win." The up-spring was resisting
> the aero forces
> > that want to make the airplane dive, but those forces now
> win and the
> > airplane dives. Conversely, if the down-spring is loaded at
> cruise, then a
> > nose drop again means larger aero forces, but those forces
> (from the
> > sparrow
> > strainers) act to RAISE the nose, not lower it further.
> Raising the nose
> > restores the airplane to level flight.
> >
> > Rutan advised his builders that his airplane designs should be
> > AERODYNAMICALLY trimmed to a low-cruise airspeed when flown
> hands-off and
> > with the pitch trim system disconnected. His rationale is that if a
> > crucial
> > part or connection in the pitch control system should fail
> thereby leaving
> > an elevator completely disconnected from the trim system
> and the control
> > system, it does not automatically kill the pilot. I do NOT advise
> > disconnecting the trim system in a Q2 or Q200 or even a
> Quickie because of
> > the risks involved, but you can certainly look at your trim
> springs and
> > simulate a disconnect by moving the trim control to make
> them as equally
> > slack as possible. By this method one might be able to get
> a relative idea
> > of what the sparrow strainers are doing and what the airplane's
> > aerodynamic
> > trim speed is.
> >
> > In summary, I think there is a dangerous situation being
> described by Mr.
> > Q2fun and I hope he gets his sparrow strainers and trim
> system looked at
> > by
> > one of the "old heads" on this list to see if it is rigged
> right or if
> > there's something amiss. I'll wager that the up-spring is
> doing a lot of
> > work at cruise speeds and just loses the battle against
> aero forces at
> > speeds above 150 mph. Not good -- not safe!
> >
> > Just my worry-wart two cents worth,
> >
> >
> > David J. Gall
> > BSAE
> > Sacramento, CA
> >
> >> -----Original Message-----
> >> From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
> >> On Behalf Of Sam Hoskins
> >> Sent: Monday, October 16, 2006 5:02 PM
> >> To: Q-LIST@yahoogroups.com
> >> Subject: RE: [Q-LIST] Flight characteristics questions
> >>
> >> 1. I think pitch sensitivity is normal, especially with aft
> >> CG and at high
> >> (8,000+ft) altitude.
> >>
> >> 2. My plane does the same. The rudder doesn't control bank,
> >> the ailerons do.
> >>
> >> 2. This sounds a little odd. Maybe the sparrow strainers
> >> are too big or have too steep of an angle. It could also be
> >> that your canard needs to be adjusted up a degree or so.
> >> Maybe try installing adjustable sparrow strainers first.
> >> That would be an easy experiment.
> >>
> >> Sam Hoskins Q-200 1,600+ hrs.
> >>
> >> Murphysboro, IL
> >>
> >>
> >>
> >> _____
> >>
> >> From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
> >> On Behalf Of q2fun
> >> Sent: Monday, October 16, 2006 6:28 PM
> >> To: Q-LIST@yahoogroups.com
> >> Subject: [Q-LIST] Flight characteristics questions
> >>
> >>
> >>
> >> Hi All,
> >>
> >> I have some questions about the flight characteristics of the Q-2.
> >> Pitch sensitivity. With an after c/g my Q2 seams pitch sensitive.
> >> My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
> >> normal to get more pitch sensitive the more aft the C/G gets?
> >>
> >> Rudder to control bank. My rudder does not do anything for bank.
> >> If the wing is down 5 degrees and you use the rudder to bring
> >> it up, all that happens is the plane will yaw and the bank
> >> may even get steeper. Is that a normal characteristic of the
> >> Q design?
> >>
> >> With an increase in airspeed above 150 mph indicated the
> >> airplane wants to pitch down and farther increase
> >> airspeed/pitch down harder. Is this normal? Sparrow strainers
> >> to small for this airspeed? I have the standard pitch trim system.
> >>
> >> I have been flying my Q since April and now have 62 hours in
> >> it. It is a joy to blast around the pattern and it is even a
> >> joy to put gas in it after a long cross county. It is just a
> >> little too slow in cruise 130 kts.
> >>
> >> Thank You All.
> >> Tim Bryant
> >> KUNV
> >> N86TB






------------------------------------------------------------------------------


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Checked by AVG Free Edition.
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Peter Harris <peterjfharris@...>
 

David for what it's worth the subject of pitch spring effect came up a
couple of years ago. I had complained that when the engine quit there is a
scramble to adjust the trim to hold the nose up. The trim spring made the
nose seem VERY heavy at a time when we do not need that kind of a
distraction and my plans adjuster was stiff and hard to reach with the left
hand. I was not going to let go of the stick! . I was surprised to find
that most of the guys let the trim freewheel unlocked. It is not designed
that way due to the mechanical advantage but if the bearing is made loose in
construction it would freewheel like a buzz saw. Anyhow I redesigned my trim
so it is now operated by a throttle cable control near my left hand and very
easy to disengage. It is a real pleasure to use close to the throttle, I
lock it only when stabilized in cruise, and also I lock it fully elevator up
for final approach and flare. (My throttle is done with a mixture adjuster
cable and that is also nice to use, just set and forget)

At the present time I am dealing with a related problem: Although trimmed
max elev up I need forward pressure to hold the nose down and TE up (3/16"
at 170KTS). Aeleron reflex is 3/8"up. Unless I made a mistake the CG is
same as for the Norton but the Norton line of thrust was 17mm higher. Do you
think that the thrust couple would explain the issue? I am planning to flush
the aelerons again.

Peter



_____

From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com] On Behalf Of
David J. Gall
Sent: Tuesday, 17 October 2006 7:43 PM
To: Q-LIST@yahoogroups.com
Subject: RE: [Q-LIST] Flight characteristics questions



Sam,

I think you're thinking backwards here. The described behavior indicates
sparrow strainers that are too small, not too large; or not angled enough
(trailing edge up) instead of too steeply.

Without sparrow strainers, when the airplane inadvertently goes faster than
its trimmed airspeed, the slight undercamber of the LS(1) elevator causes
aerodynamic force that pushes the trailing edge of the elevator up. This
lets the airplane's nose come down and allows the airplane to accelerate to
a yet-higher speed. NOT GOOD!

The sole purpose of sparrow strainers is to REVERSE this pattern. When the
nose inadvertently drops and the speed builds, the sparrow strainers should
push the trailing edge of the elevator down so as to raise the nose of the
airplane, thus slowing it back down. Conversely, when the airplane slows
down (due to an inadvertent climb) the decreasing dynamic pressure on the
sparrow strainers lets them allow the trailing edge of the elevators to come
up (usually in response to a down-spring in the trim system), lowering the
nose and restoring the airplane to it's original airspeed.

This is speed stability. It is closely associated with pitch stability, but
is not the same thing. Burt Rutan devoted several issues of his Canard
Pusher newsletter to describing it, discussing it, and reporting on the
requirements for it in his several homebuilders' designs.

Another clue to incorrect speed stability is light or "sensitive" pitch
control, as reported in Mr. Q2fun's item #1. True, pitch sensitivity is also
a function of CG position, but given two otherwise identical airplanes with
the same CG location, the one with greater speed stability will have
less-sensitive pitch feel. That's because the greater aerodynamic forces of
the larger or more effective (larger/correct deflection angle) sparrow
strainers will cause the elevator stick force to be greater for any given
deflection of the elevators away from their trim position. It's kind of like
using a larger paddle on a canoe, you just have to pull harder to get it to
move through the water.

A more effective sparrow strainer will also need to be met with greater
tension in the pitch down-spring of the spring-type pitch trim system at
higher airspeeds. If the down spring of the trim system is only lightly
loaded at cruise speed or if the up-spring is loaded and the down spring is
slack at cruise speed (heaven forbid!) then there is a real problem and a
potentially dangerous situation.

What happens if the up-spring is loaded at cruise? If the nose drops, the
aerodynamic forces get stronger while the spring force stays the same, so
the aerodynamic forces "win." The up-spring was resisting the aero forces
that want to make the airplane dive, but those forces now win and the
airplane dives. Conversely, if the down-spring is loaded at cruise, then a
nose drop again means larger aero forces, but those forces (from the sparrow
strainers) act to RAISE the nose, not lower it further. Raising the nose
restores the airplane to level flight.

Rutan advised his builders that his airplane designs should be
AERODYNAMICALLY trimmed to a low-cruise airspeed when flown hands-off and
with the pitch trim system disconnected. His rationale is that if a crucial
part or connection in the pitch control system should fail thereby leaving
an elevator completely disconnected from the trim system and the control
system, it does not automatically kill the pilot. I do NOT advise
disconnecting the trim system in a Q2 or Q200 or even a Quickie because of
the risks involved, but you can certainly look at your trim springs and
simulate a disconnect by moving the trim control to make them as equally
slack as possible. By this method one might be able to get a relative idea
of what the sparrow strainers are doing and what the airplane's aerodynamic
trim speed is.

In summary, I think there is a dangerous situation being described by Mr.
Q2fun and I hope he gets his sparrow strainers and trim system looked at by
one of the "old heads" on this list to see if it is rigged right or if
there's something amiss. I'll wager that the up-spring is doing a lot of
work at cruise speeds and just loses the battle against aero forces at
speeds above 150 mph. Not good -- not safe!

Just my worry-wart two cents worth,

David J. Gall
BSAE
Sacramento, CA

-----Original Message-----
From: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com
[mailto:Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com]
On Behalf Of Sam Hoskins
Sent: Monday, October 16, 2006 5:02 PM
To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com
Subject: RE: [Q-LIST] Flight characteristics questions

1. I think pitch sensitivity is normal, especially with aft
CG and at high
(8,000+ft) altitude.

2. My plane does the same. The rudder doesn't control bank,
the ailerons do.

2. This sounds a little odd. Maybe the sparrow strainers
are too big or have too steep of an angle. It could also be
that your canard needs to be adjusted up a degree or so.
Maybe try installing adjustable sparrow strainers first.
That would be an easy experiment.

Sam Hoskins Q-200 1,600+ hrs.

Murphysboro, IL



_____

From: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com
[mailto:Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com]
On Behalf Of q2fun
Sent: Monday, October 16, 2006 6:28 PM
To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com
Subject: [Q-LIST] Flight characteristics questions



Hi All,

I have some questions about the flight characteristics of the Q-2.
Pitch sensitivity. With an after c/g my Q2 seams pitch sensitive.
My Q2 has the LS1 canard, Revmaster 65hp, tail dragger. Is it
normal to get more pitch sensitive the more aft the C/G gets?

Rudder to control bank. My rudder does not do anything for bank.
If the wing is down 5 degrees and you use the rudder to bring
it up, all that happens is the plane will yaw and the bank
may even get steeper. Is that a normal characteristic of the
Q design?

With an increase in airspeed above 150 mph indicated the
airplane wants to pitch down and farther increase
airspeed/pitch down harder. Is this normal? Sparrow strainers
to small for this airspeed? I have the standard pitch trim system.

I have been flying my Q since April and now have 62 hours in
it. It is a joy to blast around the pattern and it is even a
joy to put gas in it after a long cross county. It is just a
little too slow in cruise 130 kts.

Thank You All.
Tim Bryant
KUNV
N86TB









Quickie Builders Association WEB site
http://www.quickieb <http://www.quickiebuilders.org> uilders.org


Yahoo! Groups Links





David J. Gall
 

Paul,

Not underneath. On top. It is UNdesirable to have undercambered
elevators on canards. It IS desireable to have a slight REFLEX (reverse
camber near the trailing edge) on the elevators of canard airplanes.
This is one distinct reason that the choice of the LS(1)-0417MOD
airfoil was such a POOR CHOICE for a canard airfoil, despite the fact
that it has been made to work. IIRC, the LS(1) canard was rumored to be
the breaking point between Rutan and the rest of QAC.


David J. Gall

----Original Message----
From: paulbuckley@onetel.com
Date: Oct 17, 2006 13:28
To: <Q-LIST@yahoogroups.com>
Subj: Re: [Q-LIST] Flight characteristics questions

Dave

As a matter of interest, an old method of achieving trim was to 'dope'
a length of string along the airfoil trailing edge, varying the length
to achieve the desired effect.
Do you think that this method could be used underneath the GU
elevators as an alternative to camber, if only as a temporary
explorative measure?

Paul Buckley
Cheshire
England


MartinErni@...
 

Danny,
This is not a common problem. In fact yours is the first I have heard
of. It sounds to me like something is wrong with you sparrow strainers ( a
minor fix). But, I would not fly it until you figure it out. Where are you
located? Maybe another builder could help you trouble shot it.
Earnest
Triq200 960 hours


Danny Creech <dannycreech@...>
 

"David J. Gall" <David@Gall.com> wrote:
>Without sparrow strainers, when the airplane inadvertently goes faster than
its trimmed airspeed, the slight undercamber of the LS(1) elevator causes
aerodynamic force that pushes the trailing edge of the elevator up. This
lets the airplane's nose come down and allows the airplane to accelerate to
a yet-higher speed. NOT GOOD!


Couple of points here.

1. If the TRAILING edge of an elevator goes up, then the nose of the aircraft goes up. Not down. I re-read David's post several times just to make sure I wasn't missing something.


2. More important though is: Are there any other ways to fix this problem without having to put sparrow strainers on?? They increase drag, stick out being easy to damage from airshow goers, and all in all they look ugly. They look like someone didn't design something right and they had to add a fix.

Has anyone came up with some other way to fix this problem? Is this problem only on the LS1 wing or do all of the Q2s and Q200s have this problem? Would making a flush mounted tab (anti-servo or something) into the elevator work?

,___
Capt. Danny Creech
^^ Not an aerodynamic engineer obviously.


Jim Patillo
 

Danny,

When you pull the stick back on a Q in flight, the elevator is
deflected down and the result is the nose goes up. Its a canard.

Jim Patillo

--- In Q-LIST@yahoogroups.com, Danny Creech <dannycreech@...> wrote:

"David J. Gall" <David@...> wrote:
>Without sparrow strainers, when the airplane inadvertently goes
faster than
its trimmed airspeed, the slight undercamber of the LS(1) elevator
causes
aerodynamic force that pushes the trailing edge of the elevator
up. This
lets the airplane's nose come down and allows the airplane to
accelerate to
a yet-higher speed. NOT GOOD!


Couple of points here.

1. If the TRAILING edge of an elevator goes up, then the nose of
the aircraft goes up. Not down. I re-read David's post several times
just to make sure I wasn't missing something.


2. More important though is: Are there any other ways to fix
this problem without having to put sparrow strainers on?? They
increase drag, stick out being easy to damage from airshow goers,
and all in all they look ugly. They look like someone didn't design
something right and they had to add a fix.

Has anyone came up with some other way to fix this problem? Is
this problem only on the LS1 wing or do all of the Q2s and Q200s
have this problem? Would making a flush mounted tab (anti-servo or
something) into the elevator work?

,___
Capt. Danny Creech
^^ Not an aerodynamic engineer obviously.




Paul Buckley
 

Not this elevator.........it's at the front!

----- Original Message -----
From: Danny Creech
To: Q-LIST@yahoogroups.com
Sent: Wednesday, October 18, 2006 6:13 PM
Subject: RE: [Q-LIST] Flight characteristics questions


>"David J. Gall" <David@Gall.com> wrote:
>Without sparrow strainers, when the airplane inadvertently goes faster than
its trimmed airspeed, the slight undercamber of the LS(1) elevator causes
aerodynamic force that pushes the trailing edge of the elevator up. This
lets the airplane's nose come down and allows the airplane to accelerate to
a yet-higher speed. NOT GOOD!


Couple of points here.

1. If the TRAILING edge of an elevator goes up, then the nose of the aircraft goes up. Not down. I re-read David's post several times just to make sure I wasn't missing something.


2. More important though is: Are there any other ways to fix this problem without having to put sparrow strainers on?? They increase drag, stick out being easy to damage from airshow goers, and all in all they look ugly. They look like someone didn't design something right and they had to add a fix.

Has anyone came up with some other way to fix this problem? Is this problem only on the LS1 wing or do all of the Q2s and Q200s have this problem? Would making a flush mounted tab (anti-servo or something) into the elevator work?

,___
Capt. Danny Creech
^^ Not an aerodynamic engineer obviously.








------------------------------------------------------------------------------


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Checked by AVG Free Edition.
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Jon Finley <jon@...>
 

Not on our airplanes.... Elevator trailing edge up = nose down. Elevator
trailing edge down = nose up. David wrote it correctly.

This plus the fact that stick left = right roll and vice versa are the
reason that these planes are so hard to fly. ;-) (kidding about the roll
thing)

Jon Finley
N90MG - Q2 - Subaru EJ-22 Legacy
http://www.finleyweb.net/Q2Subaru
Mid-Valley Airpark, Los Lunas, NM

-----Original Message-----
From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]On Behalf Of
Danny Creech
Couple of points here.

1. If the TRAILING edge of an elevator goes up, then the nose of the
aircraft goes up. Not down. I re-read David's post several times just to
make sure I wasn't missing something.


Danny Creech <dannycreech@...>
 

Darn if your not right! As soon as you responded I thought about it and it only makes since! Sheeesh. I guess that is why I leave all the design to the engineers and I just fly them. <GRIN>

I just know I'm going to get drug through the mud for making that statment!

I guess I'm just not used to the tail being upfront where it belongs.

Your a funny guy Jon.

Danny Creech


>Not on our airplanes... . Elevator trailing edge up = nose down. Elevator
trailing edge down = nose up. David wrote it correctly.

This plus the fact that stick left = right roll and vice versa are the
reason that these planes are so hard to fly. ;-) (kidding about the roll
thing)

Jon Finley
N90MG - Q2 - Subaru EJ-22 Legacy


Danny Creech <dannycreech@...>
 

Yeah, stupid me. I knew I was going to get it on this one. GRIN

Danny Creech

Jim Patillo <logistics_engineering@msn.com> wrote:


Danny,

When you pull the stick back on a Q in flight, the elevator is
deflected down and the result is the nose goes up. Its a canard.

Jim Patillo

--- In Q-LIST@yahoogroups.com, Danny Creech <dannycreech@...> wrote:

"David J. Gall" <David@...> wrote:
Without sparrow strainers, when the airplane inadvertently goes
faster than
its trimmed airspeed, the slight undercamber of the LS(1) elevator
causes
aerodynamic force that pushes the trailing edge of the elevator
up. This
lets the airplane's nose come down and allows the airplane to
accelerate to
a yet-higher speed. NOT GOOD!


Couple of points here.

1. If the TRAILING edge of an elevator goes up, then the nose of
the aircraft goes up. Not down. I re-read David's post several times
just to make sure I wasn't missing something.


2. More important though is: Are there any other ways to fix
this problem without having to put sparrow strainers on?? They
increase drag, stick out being easy to damage from airshow goers,
and all in all they look ugly. They look like someone didn't design
something right and they had to add a fix.

Has anyone came up with some other way to fix this problem? Is
this problem only on the LS1 wing or do all of the Q2s and Q200s
have this problem? Would making a flush mounted tab (anti-servo or
something) into the elevator work?

,___
Capt. Danny Creech
^^ Not an aerodynamic engineer obviously.




Allan Farr <afarr@...>
 

David,
The elevators on my GU canard appeared to me to have been put on upside down by the original builder as the trailing edge curved up. I have gone to alot of trouble flipping them over so that the t/e curves down - do you think I should have left them as is?
Allan Farr
Q2
P.S. On fast taxi runs with the elevators as they were (t/e curved up), the canard didn't want to fly. I need all the lift I can get up front, and that is one reason why I flipped the elevators over.

----- Original Message -----
From: david@gall.com
To: Q-LIST@yahoogroups.com
Sent: Wednesday, 18 October 2006 13:11
Subject: Re: [Q-LIST] Flight characteristics questions


Paul,

Not underneath. On top. It is UNdesirable to have undercambered
elevators on canards. It IS desireable to have a slight REFLEX (reverse
camber near the trailing edge) on the elevators of canard airplanes.
This is one distinct reason that the choice of the LS(1)-0417MOD
airfoil was such a POOR CHOICE for a canard airfoil, despite the fact
that it has been made to work. IIRC, the LS(1) canard was rumored to be
the breaking point between Rutan and the rest of QAC.

David J. Gall

----Original Message----
From: paulbuckley@onetel.com
Date: Oct 17, 2006 13:28
To: <Q-LIST@yahoogroups.com>
Subj: Re: [Q-LIST] Flight characteristics questions

Dave

As a matter of interest, an old method of achieving trim was to 'dope'
a length of string along the airfoil trailing edge, varying the length
to achieve the desired effect.
Do you think that this method could be used underneath the GU
elevators as an alternative to camber, if only as a temporary
explorative measure?

Paul Buckley
Cheshire
England


Doug Humble <hawkidoug@...>
 

Allen - can you take some photos and post them to the photos folder?

Doug "Hawkeye" Humble
A Sign Above www.asignabove.net
Omaha NE
N25974

----- Original Message -----
From: Allan Farr
To: Q-LIST@yahoogroups.com
Sent: Wednesday, October 18, 2006 4:39 PM
Subject: Re: [Q-LIST] Flight characteristics questions


David,
The elevators on my GU canard appeared to me to have been put on upside down by the original builder as the trailing edge curved up. I have gone to alot of trouble flipping them over so that the t/e curves down - do you think I should have left them as is?
Allan Farr
Q2
P.S. On fast taxi runs with the elevators as they were (t/e curved up), the canard didn't want to fly. I need all the lift I can get up front, and that is one reason why I flipped the elevators over.

----- Original Message -----
From: david@gall.com
To: Q-LIST@yahoogroups.com
Sent: Wednesday, 18 October 2006 13:11
Subject: Re: [Q-LIST] Flight characteristics questions

Paul,

Not underneath. On top. It is UNdesirable to have undercambered
elevators on canards. It IS desireable to have a slight REFLEX (reverse
camber near the trailing edge) on the elevators of canard airplanes.
This is one distinct reason that the choice of the LS(1)-0417MOD
airfoil was such a POOR CHOICE for a canard airfoil, despite the fact
that it has been made to work. IIRC, the LS(1) canard was rumored to be
the breaking point between Rutan and the rest of QAC.

David J. Gall

----Original Message----
From: paulbuckley@onetel.com
Date: Oct 17, 2006 13:28
To: <Q-LIST@yahoogroups.com>
Subj: Re: [Q-LIST] Flight characteristics questions

Dave

As a matter of interest, an old method of achieving trim was to 'dope'
a length of string along the airfoil trailing edge, varying the length
to achieve the desired effect.
Do you think that this method could be used underneath the GU
elevators as an alternative to camber, if only as a temporary
explorative measure?

Paul Buckley
Cheshire
England


David J. Gall
 

Cap'n Dan,

They look like
someone didn't design something right and they had to add a fix.
BINGO! Well, not quite. Airfoil choices are a compromise and sometimes a
band-aid is needed to make a particular choice work in a particular
application. The LS(1) airfoil wasn't the only choice at the time, but it
had a goodly amount of marketing hype propelling it along in the early
'80's. We've since learned that its not such a hot GA airfoil after all, but
for a high wing loading (like on a Q200 canard) it is one of the "good"
choices. Unfortunately, its trailing edge is curved just the wrong way for a
canard elevator.

Strainers are one possible solution to fix such a problem, but not the best
for the hangar-rash issues you mention, among others. The advantage of the
strainers is that they have a long leverage arm behind the elevator hinge
line. You could use a fixed trim tab instead, but it would have to be pretty
large since it would be closer to the hinge line. See the Long-EZ "new"
canard with the Roncz 1145MS airfoil for the correct way to do it. Roncz
essentially designed a fixed trim tab into the airfoil along the entire span
of the elevator. Most people don't even notice that it is there, but it is.
It is "tweaked" so that the elevator's natural "floating" angle of
deflection is appropriate for a low cruise speed for the airplane without
any trim system or control system forces being applied. Your strainers
should be adjusted similarly, if the designers and builders did their jobs
right.

Meanwhile, since no one has adapted the Roncz airfoil to the Q-birds, I
recommend that you keep the strainers and follow the advice offered on this
list, especially the advice to have some experienced sets of eyes look over
your plane. I suspect you've got a problem with your strainers or maybe even
with the construction of your elevators.


David J. Gall
P.S. an anti-servo tab could be adapted, but it would only be flush at one
elevator deflection, likely close to full "up" elevator (trailing edge
down). Tabs, by their very nature, are not "flush."


-----Original Message-----
From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of Danny Creech
Sent: Wednesday, October 18, 2006 10:13 AM
To: Q-LIST@yahoogroups.com
Subject: RE: [Q-LIST] Flight characteristics questions

< snip! >

2. More important though is: Are there any other ways to
fix this problem without having to put sparrow strainers on??
They increase drag, stick out being easy to damage from
airshow goers, and all in all they look ugly. They look like
someone didn't design something right and they had to add a fix.

Has anyone came up with some other way to fix this problem?
Is this problem only on the LS1 wing or do all of the Q2s and
Q200s have this problem? Would making a flush mounted tab
(anti-servo or something) into the elevator work?

,___
Capt. Danny Creech
^^ Not an aerodynamic engineer obviously.


David J. Gall
 

Allan,

I don't think there's supposed to be any curve at all in the GU elevators.
My plans don't show any.


David J. Gall

-----Original Message-----
From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com]
On Behalf Of Allan Farr
Sent: Wednesday, October 18, 2006 2:40 PM
To: Q-LIST@yahoogroups.com
Subject: Re: [Q-LIST] Flight characteristics questions

David,
The elevators on my GU canard appeared to me to have been put
on upside down by the original builder as the trailing edge
curved up. I have gone to alot of trouble flipping them over
so that the t/e curves down - do you think I should have left
them as is?
Allan Farr
Q2
P.S. On fast taxi runs with the elevators as they were (t/e
curved up), the canard didn't want to fly. I need all the
lift I can get up front, and that is one reason why I flipped
the elevators over.