wing levelers

On Fri, 25 Feb 2005 13:27:00 GMT, "Dick" wrote:

Thanks for everyones input.

Our group was discussing flying in VFR only (no IMC or IFR) and wing leveler
only with respect to roll sensitivity of lightly wing loaded, short wing
spanned experimentals.

Trying to make summer flying in chop somewhat easier. We didn't plan on
turning over controls to the device and would still keep a light grip on the
stick; just wouldn't have to constantly play the stick.

Although we had the impression that a heavier plane would be more stable in
chop and require less than continual input by stick, that wasn't much of an
option G.

Although not discussed among us, I wonder if
an increased dihedral result is possible without actually increasing it
physically..

Still would appreciate a little discussion that I can pass on for the next
non-flying day.

Thanks, Dick

My Jungster II has zero dihedral, but 15° of sweepback. The wing
loading is about 13 lb per sq. ft. It is quite stable in moderate
turbulence. While it can be upset it returns to level flight with very
little input. That probably won't solve your problem, but it is
another factor.

Ed Sullivan

Morgans wrote:

"Jan Carlsson" wrote in message
...

Dick,

I think that winglets would improve roll stability, and L/D, climb
performance and high alt. performance.

Jan Carlsson


At the speeds we fly, winglets do little to nothing. They only become
useful at higher speeds.

But they will look pretty.

Dan, U.S. Air Force, retired

When I said "I think" I was very humble...

Regarding winglets I am an "expert" (definition of an expert is someone that
have read what other have don :-)
Peter Masak did a great pioneer work on effective winglets. result was
winglets that didn't decrease performance at high speed as the large earlier
winglets.

Winglets make the wing act like it was of greater span, the improvement is
larger then if the wing was lengthened the amount of the winglets height.
And the increase in bending moment is smaller then the longer wing will
produce.

Winglets and longer wings reduce the induced drag (that come from the work
of producing lift) that work is harder at low indicated speed, =slow speed
at low altitude, low indicated speed at high altitude and getting there.

So even an "high speed" jetliner will be helped by using winglets, it spend
a long time at high weight climbing to economical cruising altitude, there
it cruise at low indicated speed (what pilot see) or more correct low
dynamic pressure.

Ok, no one here on RAH build jet liner, some fly them, and some build high
performance aeroplanes that have the capability to cruise at high altitude,
other aeroplanes can benefit from improvements of winglets too, if you fly
very long distances and want most economic, you would like to cruise near
(high side of) speed for best L/D ( at alt it will still go fast) here
winglets will help a lot.
other situations is to improve take off and climb and roll stability AND
roll rate, better aileron efficiency.

In this case Dick want more stability on a ? small big M ? plane, with
winglets he get a wing that "think" that the dihedral is grater then it is,
and improve the short wings low speed performance. don correct it would not
hurt cruise performance.

Jan in ME
www.jcpropellerdesign.com
Propeller and Performance software


"Morgans" skrev i meddelandet
...

"Jan Carlsson" wrote in message
...
Dick,

I think that winglets would improve roll stability, and L/D, climb
performance and high alt. performance.

Jan Carlsson

At the speeds we fly, winglets do little to nothing. They only become
useful at higher speeds.
--
Jim in NC

"Jan Carlsson" wrote in message

When I said "I think" I was very humble...

I also attempt to be humble. You can always find someone smarter, or
bigger, or stronger or ..... than yourself.

Regarding winglets I am an "expert" (definition of an expert is someone
that
have read what other have don :-)

Perhaps I have more reading to do.

Peter Masak did a great pioneer work on effective winglets. result was
winglets that didn't decrease performance at high speed as the large
earlier
winglets.

Winglets make the wing act like it was of greater span,

This I know.

the improvement is
larger then if the wing was lengthened the amount of the winglets height.
And the increase in bending moment is smaller then the longer wing will
produce.

This I did not know.

Winglets and longer wings reduce the induced drag (that come from the work
of producing lift) that work is harder at low indicated speed, =slow speed
at low altitude, low indicated speed at high altitude and getting there.

So even an "high speed" jetliner will be helped by using winglets, it
spend
a long time at high weight climbing to economical cruising altitude, there
it cruise at low indicated speed (what pilot see) or more correct low
dynamic pressure.

Do you have any suggestions that I could do some more reading? I hate it
when I am wrong! :-)
--
Jim in NC

My humour doesn't always come to its right in English not even Swedish. Some
people recognise it as humor. :-)

There was an article by Peter Masak on the net some years ago, I have saved
it on the puter at my office.

As an Captain you can always ref. to §1= Captain is always right. or
§2=if Captain is wrong, §1 is what rules. (not a good one in a plane)

Jan
www.jcpropellerdesign.com


"Morgans" skrev i meddelandet
...

"Jan Carlsson" wrote in message

When I said "I think" I was very humble...

I also attempt to be humble. You can always find someone smarter, or
bigger, or stronger or ..... than yourself.

Regarding winglets I am an "expert" (definition of an expert is someone
that
have read what other have don :-)

Perhaps I have more reading to do.

Peter Masak did a great pioneer work on effective winglets. result was
winglets that didn't decrease performance at high speed as the large
earlier
winglets.

Winglets make the wing act like it was of greater span,

This I know.

the improvement is
larger then if the wing was lengthened the amount of the winglets
height.
And the increase in bending moment is smaller then the longer wing will
produce.

This I did not know.

Winglets and longer wings reduce the induced drag (that come from the
work
of producing lift) that work is harder at low indicated speed, =slow
speed
at low altitude, low indicated speed at high altitude and getting there.

So even an "high speed" jetliner will be helped by using winglets, it
spend
a long time at high weight climbing to economical cruising altitude,
there
it cruise at low indicated speed (what pilot see) or more correct low
dynamic pressure.

Do you have any suggestions that I could do some more reading? I hate it
when I am wrong! :-)
--
Jim in NC

Jim,

In addition the to article I mentioned earlier,
http://www.soaridaho.com/Schreder/Te...lets/Masak.htm, take a look
at the series posted on
http://www.soaridaho.com/Schreder/Te...ts/PSU_Ref.htm

Wayne
http://www.soaridaho.com/Schreder


"Morgans" wrote in message
...


Do you have any suggestions that I could do some more reading? I hate it
when I am wrong! :-)
--
Jim in NC

Morgans wrote:


Do you have any suggestions that I could do some more reading? I hate it
when I am wrong! :-)

I thought I was wrong once, But I was mistaken!.
John

From the model airplane world here is a product that controls both
pitch and roll.

http://www.futaba-rc.com/radioaccys/futm0999.html

It operates by optically referencing the horizon. So your day VFR
application would be a coincident limitation.

I don't know how current autopilots mechanically couple to the flight
controls but there are very large hobby servos that could probaby be
powerful enough to nudge the controls back and forth in response the
the control unit.

You could either just use their sensor and build your own controller or
attempt to use their controller.

BTW- The vibrating piezo gyros used for RC helecopters have some slow
drift so you can't use them directly but they do have a lot of promise
still for a stabization system. In the hobby application they act more
as dampers than absolute references as the horizon would be for the
earlier mentioned method. So the hobby gyro could counteract bumps but
the steady state error would have to be maintaned by the pilot.

Regards

Dick wrote:
Sitting around the hanger and discussing the possibility of somehow
using
off-the-shelf electronic/computer components or gadgits for
semi-automatic
wing leveling on lightly loaded, short wingspans.

Not being computer guys, the current thought is that something should
be out
there that is available cheaply and modifiable to use a simple wing
leveler.

Having heard someplace that automotive computers, as an example,
sense data
millions of times leads us to believe that sensing the wing tip
initial
movement and counteracting very very quickly would be a good thing.

As an example: One fellow pictured a rolling ball bearing inside a
tube
somehow activating a magnetic switch which in turn pulses a dc linear
motor
to operate the aileron minutely.

We are not sure how to detect the very earliest initial wing tip
movement or
drive the small trim type motor and would appreciate some thoughts
or site
recommendations to investigate.

Thanks, Dick

Ah. You might consider pursuing developing a "rate damper". This would be
much simpler than trying to control attitude, as it would only require
sensing of rate. This would not act as a wing leveler (well, not exactly,
but it might provide some attitude stabilization without correcting for
drift), but it would respond to bumps. You'd still fly attitude, but the
damper would handle the transients due to turbulence, etc.

Being a flight controls engineer, I won't advise you further on this project
(not willing to assume any liability on a project I don't control), but I
will provide the following advice:
(1) Incorporating such capabilities on an aircraft is LOADED with very
serious potential hazards, all of which can be mitigated by a very careful
and conservative system buildup. These include:
- PIO susceptibility
- runaway servos that can make it difficult/impossible for the pilot to
fly the airplane
- high transient electrical loads
- high mechanical loads on your airplane
(2) Set things up so that you can always turn it off quickly and revert to a
normal airplane (i.e. no mechanical load on flight controls from an
unpowered servo. Set it up so you can always mechanically trim out what you
get from a stuck, hard-over servo.
(3) Instrument the system thoroughly during development and test so that you
know how hard you're working your airplane.

Check with some R/C modelers to get the idea on how to set something like
this up.

"Dick" wrote in message
m...
Trying to make summer flying in chop somewhat easier. We didn't plan on
turning over controls to the device and would still keep a light grip on
the
stick; just wouldn't have to constantly play the stick.

wrote:

From the model airplane world here is a product that controls both
pitch and roll.

http://www.futaba-rc.com/radioaccys/futm0999.html

It operates by optically referencing the horizon. So your day VFR
application would be a coincident limitation.

I don't know how current autopilots mechanically couple to the flight
controls but there are very large hobby servos that could probaby be
powerful enough to nudge the controls back and forth in response the
the control unit.

The servos you describe would be strong enough in a small aircraft since
autopilots I have worked on don't move the primary control surfaces
directly. They move trim tabs.

You could either just use their sensor and build your own controller or
attempt to use their controller.

BTW- The vibrating piezo gyros used for RC helecopters have some slow
drift so you can't use them directly but they do have a lot of promise
still for a stabization system. In the hobby application they act more
as dampers than absolute references as the horizon would be for the
earlier mentioned method. So the hobby gyro could counteract bumps but
the steady state error would have to be maintaned by the pilot.

There are pizeo gyros out there that are less drifty. If you have the
money go look at Crossbow. Their systems are interesting. Among other
things they make AHRS and INS modules.

Dan, U.S. Air Force, retired