90 MODEL AVIATION
The twisted truth about warps
Safety Comes First Dave Gee | [email protected]
Also included in this column:
• Weather to fly or not
• Allergies as a guide to
workshop layout
• Another kid gets her picture
in MA
Sam Gengo was eager to try his sleek new electric wing, but the
wind sock said no. Wise fliers know when to surrender to the
weather.
RTF electric FF models are popular; there is a large selection on
the market. Teresa Eddingfield likes to color-coordinate her
model and her outfit.
Now that’s a warped wing! Don Smith’s Indoor No-Cal P-40 has won several contests in
spite of or because of that extreme trim. Check your models for warps.
WARPS! Those dreaded unplanned
curvatures that appear in the wings, tails,
and rotors of our models can spell disaster.
Wooden structures are always vulnerable to
warpage, and even foamies need to be
checked for straightness and proper
alignment.
If you build your own models you know
about the need to “eyeball” the surfaces
during construction. Certain building
techniques such as geodetic construction or
triangular bracing can make it harder for
warps to sneak in. A prudent modeler will
check an aircraft during and after the
building process, and especially when
dusting the winter cobwebs off of a stored
model in springtime.
As does intestinal bacteria, warps come
in good and bad varieties. Look at the
picture of Don Smith’s well-worn P-40 No-
Cal model. Don’t try flying your outdoor RC
airplane with that much twist in the wing!
This is an extreme case of wing warpage,
but it is also the exception to the rule
because this model is designed for indoor
flying under a low ceiling. The
asymmetrical wings actually help it fly the
tight circles necessary to avoid collisions
with the walls. Don takes some ribbing
about this model, but he can afford to be big
about it since it is a proven contest winner!
Few airplanes, model or full-scale, can
fly with straight surfaces. Intentional warps
are built into most aircraft.
Wings that have washout will stall more
gently since the tips angle down more than
the roots. The torque and airflow from a
single rotating propeller often require builtin
compensation at the tail. This is
especially important in an FF model, which
must maintain stability all by itself.
Check out a lightplane at the airport
sometime and you’ll see the same feature.
Student pilots appreciate it!
Some model plans specify that an offset
rudder or other permanent adjustment be
added during construction. You may have
heard a version of the story about a hand-
me-down model that was inspected by a new
owner who found, to his horror, that the
flying surfaces were full of warps.
After steaming, clamping, and rebracing,
the airplane was finally straight, but the test
flight resulted in a disastrous crash. A
consultation with the designer or builder or
plans afterward revealed that the original
warps were deliberate and necessary!
Pilots who fly foam models have much less
concern about warped wings, but if they’re
in this column you can bet there’s some
problem lurking. Check out the photo of
Sam Gengo with his sleek, new electric
flying wing. He was all set to try it out until
he saw the weather conditions at the local
field.
Thanks to my poor photographic skills,
the wind sock appears to be growing out of
Sam’s shoulder. Actually it is flying high
above the taxiway, and a horizontal sock
means trouble for lightweight models! Sam
and his model were disappointed but
showed wisdom and prudence in postponing
the wing’s maiden flight.
Modelers do not always use such sound
judgment when weighing their eagerness to
fly against adverse conditions, and the trashcan
contents at the field prove it.
Speaking of poor judgment, I recently
moved into a larger home and I write this
while surrounded by unpacked boxes. One
of the most important features in choosing a
new place was a suitable workshop area.
When I was a young fellow a bit of table
space in the dining room would do, but
nowadays I face the dangers of allergic
reaction to my modeling materials, spillage,
sawdust mess, and a possible scolding from
my wife Sweet Diedra if I stink up the house
with dope.
Luckily the mild California weather
allows for plenty of ventilation year-round. I
have my worktable next to a sliding-glass
door, and an open window behind me holds
an inexpensive exhaust fan to carry fumes
and dust across my workboard and out of
the house. Power sanding can be done
outside on a wheeled table that holds my
trusty Dremel Moto-Shop and disc sander.
As do many other old guys I have had to
develop the habit of wearing a dust-filter
mask when sanding. The sawdust I ignored
as a kid now bothers me plenty! Careful
planning of this work area will save a great
deal of trouble in the coming years and
allow domestic bliss to continue.
Don Lewis E-mailed me a copy of a
seasonal safety reminder from The Tailwind:
the newsletter for the Hendersonville Radio
Control Club of Hendersonville, Tennessee.
It’s not a bad idea to occasionally give an
overview of the basics. There’s always
something new to be learned or relearned.
Following is an excerpt that applies to
me especially.
“Keep your work area neat and orderly.
In addition to being able to find what you
are looking for when you need it, you lessen
the chance of tripping over something and
injuring yourself (or worse, damaging the
airplane you just finished).
“There is an old saying in the Navy that
we should keep in mind: There is a place for
everything, and everything should be in its
place. Pick up after yourself and return tools
where they go after each time you use them.
You will have a happier time in the shop and
will work more efficiently in the long run.”
Don was most kind to send that info, but
we live in different worlds; I can’t even find
my desk chair sometimes.
I appreciate it when newsletter editors
send me E-mail copies of their safety
features. Input from readers is always
welcome. If you have helpful or sardonic
comments, please E-mail me or drop a letter
to Box 7081, Van Nuys CA 91409. And
don’t worry; nobody is made to look foolish
in this column except me.
Sometime ago I published information
about a possible case of RC interference
from a lawnmower engine. Phil Shellabarger
read between the lines and brought up an
excellent point. He wrote:
“I wonder why they would allow anyone
to be mowing near the runways while
aircraft were flying. If an airplane were out
of control and headed for the guy mowing,
he could not be warned due to the noise of
the mower. At our field mowing is only
done before or after flying.”
My recollection is that the mowing was
being done at a safe distance from the
aircraft, plenty far enough to ensure safety,
but I should have made that clear originally!
Continuing onward, following is a story
from John Goegl, who probably gets his last
name mispronounced as often as I do. His
information muddies the waters even further
regarding the possibility of such
interference. He wrote:
“My neighbors had a large-screen TV in
their glassed-in sunroom. The position of
this TV made it highly visible from my
property, and it was usually ‘on’ during
waking hours.
“I noticed that whenever I ran my lawn
mower their TV experienced video
interference. Stopping the engine stopped
the TVI, but, more important, restarting the
engine restarted the TVI!
“This was a late-model TV, not some
1950s-vintage clunker, and it was over 100
feet from my mower. Most important, the
TV was connected to a cable system via
shielded coaxial cable—not to an outside
antenna!
“How could the ‘signal’ from my simple
lawn mower engine magneto get into, and
interfere with, such a high-tech setup? (A
rhetorical question, by the way!) And to
make things even more problematic, there
was no interference on my TV, on the same
cable, but much closer to the mower!
“Based on this, I have to disagree with
the position taken by the authorities at
Muncie regarding the likelihood of lawn
mower ignition systems interfering with RC.
I would advise a more open-minded
approach.”
John certainly has a point about
remaining open-minded to unforeseen
interference situations. I am not smart
enough to explain incidents such as this, but
I am prudent enough to carefully range test
when flying RC.
This column includes a picture of Teresa
Eddingfield displaying her electric FF foam
RTF model. There are many models such as
this available these days, with excellent
power systems that outlast the original
airframe and are reincarnated in scratchbuilt
airplanes.
Some builders add a motor timer to
avoid fly-aways. RC use generally requires
a dampening circuit to stop the typical
electrical “noise” from such small,
inexpensive motors.
Tinkerers often get together on the
Internet and swap experimental data about
modifying RTF models. It’s fun to follow
behind them and read “threads” on what
works and what doesn’t with a given model.
I found a 165-page discussion about my
Aero Ace biplane and was able to pick the
best soup-up tricks, thanks to clever
modelers who were most generous with
their findings.
Teresa’s dad is a well-respected local
flier, and she often accompanies him to the
field to make wisecracks about my models
and try to cadge goodies from the prize table.
Maybe now that I have put her photo in the
magazine she’ll take it easy on me. MA
Edition: Model Aviation - 2007/04
Page Numbers: 90,92,94
Edition: Model Aviation - 2007/04
Page Numbers: 90,92,94
90 MODEL AVIATION
The twisted truth about warps
Safety Comes First Dave Gee | [email protected]
Also included in this column:
• Weather to fly or not
• Allergies as a guide to
workshop layout
• Another kid gets her picture
in MA
Sam Gengo was eager to try his sleek new electric wing, but the
wind sock said no. Wise fliers know when to surrender to the
weather.
RTF electric FF models are popular; there is a large selection on
the market. Teresa Eddingfield likes to color-coordinate her
model and her outfit.
Now that’s a warped wing! Don Smith’s Indoor No-Cal P-40 has won several contests in
spite of or because of that extreme trim. Check your models for warps.
WARPS! Those dreaded unplanned
curvatures that appear in the wings, tails,
and rotors of our models can spell disaster.
Wooden structures are always vulnerable to
warpage, and even foamies need to be
checked for straightness and proper
alignment.
If you build your own models you know
about the need to “eyeball” the surfaces
during construction. Certain building
techniques such as geodetic construction or
triangular bracing can make it harder for
warps to sneak in. A prudent modeler will
check an aircraft during and after the
building process, and especially when
dusting the winter cobwebs off of a stored
model in springtime.
As does intestinal bacteria, warps come
in good and bad varieties. Look at the
picture of Don Smith’s well-worn P-40 No-
Cal model. Don’t try flying your outdoor RC
airplane with that much twist in the wing!
This is an extreme case of wing warpage,
but it is also the exception to the rule
because this model is designed for indoor
flying under a low ceiling. The
asymmetrical wings actually help it fly the
tight circles necessary to avoid collisions
with the walls. Don takes some ribbing
about this model, but he can afford to be big
about it since it is a proven contest winner!
Few airplanes, model or full-scale, can
fly with straight surfaces. Intentional warps
are built into most aircraft.
Wings that have washout will stall more
gently since the tips angle down more than
the roots. The torque and airflow from a
single rotating propeller often require builtin
compensation at the tail. This is
especially important in an FF model, which
must maintain stability all by itself.
Check out a lightplane at the airport
sometime and you’ll see the same feature.
Student pilots appreciate it!
Some model plans specify that an offset
rudder or other permanent adjustment be
added during construction. You may have
heard a version of the story about a hand-
me-down model that was inspected by a new
owner who found, to his horror, that the
flying surfaces were full of warps.
After steaming, clamping, and rebracing,
the airplane was finally straight, but the test
flight resulted in a disastrous crash. A
consultation with the designer or builder or
plans afterward revealed that the original
warps were deliberate and necessary!
Pilots who fly foam models have much less
concern about warped wings, but if they’re
in this column you can bet there’s some
problem lurking. Check out the photo of
Sam Gengo with his sleek, new electric
flying wing. He was all set to try it out until
he saw the weather conditions at the local
field.
Thanks to my poor photographic skills,
the wind sock appears to be growing out of
Sam’s shoulder. Actually it is flying high
above the taxiway, and a horizontal sock
means trouble for lightweight models! Sam
and his model were disappointed but
showed wisdom and prudence in postponing
the wing’s maiden flight.
Modelers do not always use such sound
judgment when weighing their eagerness to
fly against adverse conditions, and the trashcan
contents at the field prove it.
Speaking of poor judgment, I recently
moved into a larger home and I write this
while surrounded by unpacked boxes. One
of the most important features in choosing a
new place was a suitable workshop area.
When I was a young fellow a bit of table
space in the dining room would do, but
nowadays I face the dangers of allergic
reaction to my modeling materials, spillage,
sawdust mess, and a possible scolding from
my wife Sweet Diedra if I stink up the house
with dope.
Luckily the mild California weather
allows for plenty of ventilation year-round. I
have my worktable next to a sliding-glass
door, and an open window behind me holds
an inexpensive exhaust fan to carry fumes
and dust across my workboard and out of
the house. Power sanding can be done
outside on a wheeled table that holds my
trusty Dremel Moto-Shop and disc sander.
As do many other old guys I have had to
develop the habit of wearing a dust-filter
mask when sanding. The sawdust I ignored
as a kid now bothers me plenty! Careful
planning of this work area will save a great
deal of trouble in the coming years and
allow domestic bliss to continue.
Don Lewis E-mailed me a copy of a
seasonal safety reminder from The Tailwind:
the newsletter for the Hendersonville Radio
Control Club of Hendersonville, Tennessee.
It’s not a bad idea to occasionally give an
overview of the basics. There’s always
something new to be learned or relearned.
Following is an excerpt that applies to
me especially.
“Keep your work area neat and orderly.
In addition to being able to find what you
are looking for when you need it, you lessen
the chance of tripping over something and
injuring yourself (or worse, damaging the
airplane you just finished).
“There is an old saying in the Navy that
we should keep in mind: There is a place for
everything, and everything should be in its
place. Pick up after yourself and return tools
where they go after each time you use them.
You will have a happier time in the shop and
will work more efficiently in the long run.”
Don was most kind to send that info, but
we live in different worlds; I can’t even find
my desk chair sometimes.
I appreciate it when newsletter editors
send me E-mail copies of their safety
features. Input from readers is always
welcome. If you have helpful or sardonic
comments, please E-mail me or drop a letter
to Box 7081, Van Nuys CA 91409. And
don’t worry; nobody is made to look foolish
in this column except me.
Sometime ago I published information
about a possible case of RC interference
from a lawnmower engine. Phil Shellabarger
read between the lines and brought up an
excellent point. He wrote:
“I wonder why they would allow anyone
to be mowing near the runways while
aircraft were flying. If an airplane were out
of control and headed for the guy mowing,
he could not be warned due to the noise of
the mower. At our field mowing is only
done before or after flying.”
My recollection is that the mowing was
being done at a safe distance from the
aircraft, plenty far enough to ensure safety,
but I should have made that clear originally!
Continuing onward, following is a story
from John Goegl, who probably gets his last
name mispronounced as often as I do. His
information muddies the waters even further
regarding the possibility of such
interference. He wrote:
“My neighbors had a large-screen TV in
their glassed-in sunroom. The position of
this TV made it highly visible from my
property, and it was usually ‘on’ during
waking hours.
“I noticed that whenever I ran my lawn
mower their TV experienced video
interference. Stopping the engine stopped
the TVI, but, more important, restarting the
engine restarted the TVI!
“This was a late-model TV, not some
1950s-vintage clunker, and it was over 100
feet from my mower. Most important, the
TV was connected to a cable system via
shielded coaxial cable—not to an outside
antenna!
“How could the ‘signal’ from my simple
lawn mower engine magneto get into, and
interfere with, such a high-tech setup? (A
rhetorical question, by the way!) And to
make things even more problematic, there
was no interference on my TV, on the same
cable, but much closer to the mower!
“Based on this, I have to disagree with
the position taken by the authorities at
Muncie regarding the likelihood of lawn
mower ignition systems interfering with RC.
I would advise a more open-minded
approach.”
John certainly has a point about
remaining open-minded to unforeseen
interference situations. I am not smart
enough to explain incidents such as this, but
I am prudent enough to carefully range test
when flying RC.
This column includes a picture of Teresa
Eddingfield displaying her electric FF foam
RTF model. There are many models such as
this available these days, with excellent
power systems that outlast the original
airframe and are reincarnated in scratchbuilt
airplanes.
Some builders add a motor timer to
avoid fly-aways. RC use generally requires
a dampening circuit to stop the typical
electrical “noise” from such small,
inexpensive motors.
Tinkerers often get together on the
Internet and swap experimental data about
modifying RTF models. It’s fun to follow
behind them and read “threads” on what
works and what doesn’t with a given model.
I found a 165-page discussion about my
Aero Ace biplane and was able to pick the
best soup-up tricks, thanks to clever
modelers who were most generous with
their findings.
Teresa’s dad is a well-respected local
flier, and she often accompanies him to the
field to make wisecracks about my models
and try to cadge goodies from the prize table.
Maybe now that I have put her photo in the
magazine she’ll take it easy on me. MA
Edition: Model Aviation - 2007/04
Page Numbers: 90,92,94
90 MODEL AVIATION
The twisted truth about warps
Safety Comes First Dave Gee | [email protected]
Also included in this column:
• Weather to fly or not
• Allergies as a guide to
workshop layout
• Another kid gets her picture
in MA
Sam Gengo was eager to try his sleek new electric wing, but the
wind sock said no. Wise fliers know when to surrender to the
weather.
RTF electric FF models are popular; there is a large selection on
the market. Teresa Eddingfield likes to color-coordinate her
model and her outfit.
Now that’s a warped wing! Don Smith’s Indoor No-Cal P-40 has won several contests in
spite of or because of that extreme trim. Check your models for warps.
WARPS! Those dreaded unplanned
curvatures that appear in the wings, tails,
and rotors of our models can spell disaster.
Wooden structures are always vulnerable to
warpage, and even foamies need to be
checked for straightness and proper
alignment.
If you build your own models you know
about the need to “eyeball” the surfaces
during construction. Certain building
techniques such as geodetic construction or
triangular bracing can make it harder for
warps to sneak in. A prudent modeler will
check an aircraft during and after the
building process, and especially when
dusting the winter cobwebs off of a stored
model in springtime.
As does intestinal bacteria, warps come
in good and bad varieties. Look at the
picture of Don Smith’s well-worn P-40 No-
Cal model. Don’t try flying your outdoor RC
airplane with that much twist in the wing!
This is an extreme case of wing warpage,
but it is also the exception to the rule
because this model is designed for indoor
flying under a low ceiling. The
asymmetrical wings actually help it fly the
tight circles necessary to avoid collisions
with the walls. Don takes some ribbing
about this model, but he can afford to be big
about it since it is a proven contest winner!
Few airplanes, model or full-scale, can
fly with straight surfaces. Intentional warps
are built into most aircraft.
Wings that have washout will stall more
gently since the tips angle down more than
the roots. The torque and airflow from a
single rotating propeller often require builtin
compensation at the tail. This is
especially important in an FF model, which
must maintain stability all by itself.
Check out a lightplane at the airport
sometime and you’ll see the same feature.
Student pilots appreciate it!
Some model plans specify that an offset
rudder or other permanent adjustment be
added during construction. You may have
heard a version of the story about a hand-
me-down model that was inspected by a new
owner who found, to his horror, that the
flying surfaces were full of warps.
After steaming, clamping, and rebracing,
the airplane was finally straight, but the test
flight resulted in a disastrous crash. A
consultation with the designer or builder or
plans afterward revealed that the original
warps were deliberate and necessary!
Pilots who fly foam models have much less
concern about warped wings, but if they’re
in this column you can bet there’s some
problem lurking. Check out the photo of
Sam Gengo with his sleek, new electric
flying wing. He was all set to try it out until
he saw the weather conditions at the local
field.
Thanks to my poor photographic skills,
the wind sock appears to be growing out of
Sam’s shoulder. Actually it is flying high
above the taxiway, and a horizontal sock
means trouble for lightweight models! Sam
and his model were disappointed but
showed wisdom and prudence in postponing
the wing’s maiden flight.
Modelers do not always use such sound
judgment when weighing their eagerness to
fly against adverse conditions, and the trashcan
contents at the field prove it.
Speaking of poor judgment, I recently
moved into a larger home and I write this
while surrounded by unpacked boxes. One
of the most important features in choosing a
new place was a suitable workshop area.
When I was a young fellow a bit of table
space in the dining room would do, but
nowadays I face the dangers of allergic
reaction to my modeling materials, spillage,
sawdust mess, and a possible scolding from
my wife Sweet Diedra if I stink up the house
with dope.
Luckily the mild California weather
allows for plenty of ventilation year-round. I
have my worktable next to a sliding-glass
door, and an open window behind me holds
an inexpensive exhaust fan to carry fumes
and dust across my workboard and out of
the house. Power sanding can be done
outside on a wheeled table that holds my
trusty Dremel Moto-Shop and disc sander.
As do many other old guys I have had to
develop the habit of wearing a dust-filter
mask when sanding. The sawdust I ignored
as a kid now bothers me plenty! Careful
planning of this work area will save a great
deal of trouble in the coming years and
allow domestic bliss to continue.
Don Lewis E-mailed me a copy of a
seasonal safety reminder from The Tailwind:
the newsletter for the Hendersonville Radio
Control Club of Hendersonville, Tennessee.
It’s not a bad idea to occasionally give an
overview of the basics. There’s always
something new to be learned or relearned.
Following is an excerpt that applies to
me especially.
“Keep your work area neat and orderly.
In addition to being able to find what you
are looking for when you need it, you lessen
the chance of tripping over something and
injuring yourself (or worse, damaging the
airplane you just finished).
“There is an old saying in the Navy that
we should keep in mind: There is a place for
everything, and everything should be in its
place. Pick up after yourself and return tools
where they go after each time you use them.
You will have a happier time in the shop and
will work more efficiently in the long run.”
Don was most kind to send that info, but
we live in different worlds; I can’t even find
my desk chair sometimes.
I appreciate it when newsletter editors
send me E-mail copies of their safety
features. Input from readers is always
welcome. If you have helpful or sardonic
comments, please E-mail me or drop a letter
to Box 7081, Van Nuys CA 91409. And
don’t worry; nobody is made to look foolish
in this column except me.
Sometime ago I published information
about a possible case of RC interference
from a lawnmower engine. Phil Shellabarger
read between the lines and brought up an
excellent point. He wrote:
“I wonder why they would allow anyone
to be mowing near the runways while
aircraft were flying. If an airplane were out
of control and headed for the guy mowing,
he could not be warned due to the noise of
the mower. At our field mowing is only
done before or after flying.”
My recollection is that the mowing was
being done at a safe distance from the
aircraft, plenty far enough to ensure safety,
but I should have made that clear originally!
Continuing onward, following is a story
from John Goegl, who probably gets his last
name mispronounced as often as I do. His
information muddies the waters even further
regarding the possibility of such
interference. He wrote:
“My neighbors had a large-screen TV in
their glassed-in sunroom. The position of
this TV made it highly visible from my
property, and it was usually ‘on’ during
waking hours.
“I noticed that whenever I ran my lawn
mower their TV experienced video
interference. Stopping the engine stopped
the TVI, but, more important, restarting the
engine restarted the TVI!
“This was a late-model TV, not some
1950s-vintage clunker, and it was over 100
feet from my mower. Most important, the
TV was connected to a cable system via
shielded coaxial cable—not to an outside
antenna!
“How could the ‘signal’ from my simple
lawn mower engine magneto get into, and
interfere with, such a high-tech setup? (A
rhetorical question, by the way!) And to
make things even more problematic, there
was no interference on my TV, on the same
cable, but much closer to the mower!
“Based on this, I have to disagree with
the position taken by the authorities at
Muncie regarding the likelihood of lawn
mower ignition systems interfering with RC.
I would advise a more open-minded
approach.”
John certainly has a point about
remaining open-minded to unforeseen
interference situations. I am not smart
enough to explain incidents such as this, but
I am prudent enough to carefully range test
when flying RC.
This column includes a picture of Teresa
Eddingfield displaying her electric FF foam
RTF model. There are many models such as
this available these days, with excellent
power systems that outlast the original
airframe and are reincarnated in scratchbuilt
airplanes.
Some builders add a motor timer to
avoid fly-aways. RC use generally requires
a dampening circuit to stop the typical
electrical “noise” from such small,
inexpensive motors.
Tinkerers often get together on the
Internet and swap experimental data about
modifying RTF models. It’s fun to follow
behind them and read “threads” on what
works and what doesn’t with a given model.
I found a 165-page discussion about my
Aero Ace biplane and was able to pick the
best soup-up tricks, thanks to clever
modelers who were most generous with
their findings.
Teresa’s dad is a well-respected local
flier, and she often accompanies him to the
field to make wisecracks about my models
and try to cadge goodies from the prize table.
Maybe now that I have put her photo in the
magazine she’ll take it easy on me. MA