WHY DO WE have linkage systems? To
move the control surfaces to control a
model. What if there was an arrangement
that worked without a linkage system that
offered simple setup, minimal to zero slop,
precision, durability, and more
characteristics I look for in a system? I
believe there is!
A few years ago, at an International
Miniature Aerobatic Club (IMAC) contest
in Texas, I saw a direct-drive system that
got my attention. I could tell that it was
interesting and showed a great deal of
promise.
However, the system was so radically
different that I struggled to believe the
concept worked. I had been taught so
much about conventional linkage control
systems, how could a control system with
no pushrods, linkages, or control horns be
that good?
I asked the usual questions: how does it
work, is it easy to install, and how does it
feel in the air? I had several conversations
with John DuRant, the system’s designer,
and others who had made the switch. All
their comments were positive.
I flew an Ultimate and an Extra that were
set up with the DuRant Direct Drive. My
first thought was “Wow!” It felt like I was
connected to the airplane better than I had
ever been. The system not only provided a
simpler means of installation, but it offered
better performance. I decided to try it in my
next IMAC model.
Direct drive is about controlling the travel
of a moving surface without linkages, ball
links, or control arms—all slop and failure
points on an aircraft. The system is mounted
directly to the servo and the control surface.
That is ideal; before using the system I had
noticed a trend in control arms breaking at
the servo or at the surface.
I also like the idea of not losing the
mechanical advantage. With the extreme
control-surface throws required to set up a
model for 3-D, we tend to lose the
mechanical advantage for smooth precision
flying.
To have a model set up to do both 3-D
and precision had been a compromise; I had
never liked that idea, but it was the price to
pay for the 3-D thrill. With direct drive you
obtained an all-in-one flying setup for 3-D
and precision that would lose no control
fidelity. What more could you want?
I decided to test this control system in a
Carden Aircraft 37% YAK 54. I installed
the conventional two servos per wing
panel: one for each elevator half and three
for the rudder.
When the DuRant Direct Drive kit
arrived, the first thing I noticed was that the
entire system was laser-cut from plywood.
The servo boxes were designed with
interlocking sides, so they were easy to
assemble to be square and strong.
The included instructions were easy to
follow and informative. The Direct Drive
system can be installed in almost any Giant
Scale airplane and used with any servo,
regardless of size or make. The system is
available in a variety of sizes to make its
application as simple as possible.
To complete the setup the model must be
built with a removable hinge, a computer
radio, and a MatchBox or equivalent servo
wiring system. I used the Klett giant-scale
hinges since the pins are easy to remove and
install.
The mount boxes can be purchased in
single-, double-, and triple-servo
installations. I used the single installation on
every control surface except the rudder, for
which I used the triple-servo setup.
I went step by step and had no issues
along the way. Follow along with the
photos to see how the system is built into
the model.
I used the Futaba 14MZ radio system for
servo setup and programming. The whole
process was simple and went quickly since
48 MODEL AVIATION
Step 1. The tunnels for servo extensions have been located and
the control surfaces have been hinged.
Step 2. Assemble the servo box and mark its location on the
center of the flying-surface hinge line.
Step 3. After making pilot holes, use a
Dremel tool to rough-cut the outline of
the box frame.
Step 4. Clean out the rough opening and trim the area with an X-Acto knife so the box
will fit snugly. Keep the frame as square to the hinge line as possible.
Step 6. Carefully carve out the foam with
a hot-wire tool. Keep the tool as square
to the hinge line as possible.
Step 5. Make sure the box fits tightly inside the balsa TE cutout. Keep in mind that the
plywood box will reinforce the structure once it’s glued securely in place.
How the hole looks after you remove
the foam. The servo-wire tube should
be located at the inside corner.
Step 7. The box is glued
in using epoxy or Gorilla
Glue. Mark the control
surface for the relief cut
and control arm.
Photos by John DuRant and the author unless otherwise noted
December 2007 49
Step 8. A robust 1.5-inch servo arm is
mounted to a blank 1/16 plywood control
arm with cyanoacrylate and 4-40 hardware.
Step 9. Trim the control arm to fit the taper in the control surface. The fit should be
snug, and the length should match the inside dimensions of the control surface.
Step 10. Use the hot wire to slot the controlarm
socket. The center of the servo hole
must be on the center of the hinge line.
Step 11. The area that was cut out for the
relief can be reinforced using balsa sheeting.
Sand and cover the model as usual.
Step 12. Connect the servo to the arm.
Remember to center the servo with your
radio and then slide the servo into the box.
Multiple servos per control surface
are simple to install, and there are
no binding issues.
Step 13. Run the piano wire down
the hinge line, gap-seal the surface,
and the installation is complete.
The author’s Carden Aircraft 37% YAK 54 uses two
servos per aileron. The control system’s precision is
apparent to the pilot.
Three servos on
the rudder offer
maximum control
authority.
there were no linkages. Each servo took half
the time to install than with a conventional
linkage setup.
Now for the flying part. Once I was happy
with how the airplane was trimmed, I flew
the 2007 IMAC Unlimited sequence. It felt
great, with a more locked feel than I had
ever experienced. At first I thought maybe it
was me, so I asked a few local club
members to fly my model. They all had the
same reaction.
The most interesting thing about the
field-testing was that after the guys went
back to flying their airplanes they noticed a
big difference between their linkage setups
and the Direct Drive. The first comment I
heard was that one pilot didn’t realize how
loose his model felt. He said he was going
to switch to Direct Drive on his next
airplane.
I’ve been flying my Carden aircraft with
the Durant Direct Drive system for a full
season. Well more than 100 flights are
logged on each.
I recommend this new design to anyone
who has a giant-scale model. The system is
ideal for aerobatic models because it offers
the most potential and smoothest operation
of a control surface, which is the goal of any
conscientious builder and aerobatic pilot.
I wasn’t sure about this new state-of-the-art
system at first, but now that I made the
switch I’ll never go back to the old linkage
system. The manufacturer is more than
happy to help and will answer any questions
that come up. The Web site has great
information about the setup and the history
behind Direct Drive. MA
Rick Byrd
[email protected]
Sources:
Futaba radio equipment
(800) 637-7660
www.futaba-rc.com
DuRant Direct Drive
(817) 243-8524
www.durantdirectdrive.com
Edition: Model Aviation - 2007/12
Page Numbers: 47,48,49,50
Edition: Model Aviation - 2007/12
Page Numbers: 47,48,49,50
WHY DO WE have linkage systems? To
move the control surfaces to control a
model. What if there was an arrangement
that worked without a linkage system that
offered simple setup, minimal to zero slop,
precision, durability, and more
characteristics I look for in a system? I
believe there is!
A few years ago, at an International
Miniature Aerobatic Club (IMAC) contest
in Texas, I saw a direct-drive system that
got my attention. I could tell that it was
interesting and showed a great deal of
promise.
However, the system was so radically
different that I struggled to believe the
concept worked. I had been taught so
much about conventional linkage control
systems, how could a control system with
no pushrods, linkages, or control horns be
that good?
I asked the usual questions: how does it
work, is it easy to install, and how does it
feel in the air? I had several conversations
with John DuRant, the system’s designer,
and others who had made the switch. All
their comments were positive.
I flew an Ultimate and an Extra that were
set up with the DuRant Direct Drive. My
first thought was “Wow!” It felt like I was
connected to the airplane better than I had
ever been. The system not only provided a
simpler means of installation, but it offered
better performance. I decided to try it in my
next IMAC model.
Direct drive is about controlling the travel
of a moving surface without linkages, ball
links, or control arms—all slop and failure
points on an aircraft. The system is mounted
directly to the servo and the control surface.
That is ideal; before using the system I had
noticed a trend in control arms breaking at
the servo or at the surface.
I also like the idea of not losing the
mechanical advantage. With the extreme
control-surface throws required to set up a
model for 3-D, we tend to lose the
mechanical advantage for smooth precision
flying.
To have a model set up to do both 3-D
and precision had been a compromise; I had
never liked that idea, but it was the price to
pay for the 3-D thrill. With direct drive you
obtained an all-in-one flying setup for 3-D
and precision that would lose no control
fidelity. What more could you want?
I decided to test this control system in a
Carden Aircraft 37% YAK 54. I installed
the conventional two servos per wing
panel: one for each elevator half and three
for the rudder.
When the DuRant Direct Drive kit
arrived, the first thing I noticed was that the
entire system was laser-cut from plywood.
The servo boxes were designed with
interlocking sides, so they were easy to
assemble to be square and strong.
The included instructions were easy to
follow and informative. The Direct Drive
system can be installed in almost any Giant
Scale airplane and used with any servo,
regardless of size or make. The system is
available in a variety of sizes to make its
application as simple as possible.
To complete the setup the model must be
built with a removable hinge, a computer
radio, and a MatchBox or equivalent servo
wiring system. I used the Klett giant-scale
hinges since the pins are easy to remove and
install.
The mount boxes can be purchased in
single-, double-, and triple-servo
installations. I used the single installation on
every control surface except the rudder, for
which I used the triple-servo setup.
I went step by step and had no issues
along the way. Follow along with the
photos to see how the system is built into
the model.
I used the Futaba 14MZ radio system for
servo setup and programming. The whole
process was simple and went quickly since
48 MODEL AVIATION
Step 1. The tunnels for servo extensions have been located and
the control surfaces have been hinged.
Step 2. Assemble the servo box and mark its location on the
center of the flying-surface hinge line.
Step 3. After making pilot holes, use a
Dremel tool to rough-cut the outline of
the box frame.
Step 4. Clean out the rough opening and trim the area with an X-Acto knife so the box
will fit snugly. Keep the frame as square to the hinge line as possible.
Step 6. Carefully carve out the foam with
a hot-wire tool. Keep the tool as square
to the hinge line as possible.
Step 5. Make sure the box fits tightly inside the balsa TE cutout. Keep in mind that the
plywood box will reinforce the structure once it’s glued securely in place.
How the hole looks after you remove
the foam. The servo-wire tube should
be located at the inside corner.
Step 7. The box is glued
in using epoxy or Gorilla
Glue. Mark the control
surface for the relief cut
and control arm.
Photos by John DuRant and the author unless otherwise noted
December 2007 49
Step 8. A robust 1.5-inch servo arm is
mounted to a blank 1/16 plywood control
arm with cyanoacrylate and 4-40 hardware.
Step 9. Trim the control arm to fit the taper in the control surface. The fit should be
snug, and the length should match the inside dimensions of the control surface.
Step 10. Use the hot wire to slot the controlarm
socket. The center of the servo hole
must be on the center of the hinge line.
Step 11. The area that was cut out for the
relief can be reinforced using balsa sheeting.
Sand and cover the model as usual.
Step 12. Connect the servo to the arm.
Remember to center the servo with your
radio and then slide the servo into the box.
Multiple servos per control surface
are simple to install, and there are
no binding issues.
Step 13. Run the piano wire down
the hinge line, gap-seal the surface,
and the installation is complete.
The author’s Carden Aircraft 37% YAK 54 uses two
servos per aileron. The control system’s precision is
apparent to the pilot.
Three servos on
the rudder offer
maximum control
authority.
there were no linkages. Each servo took half
the time to install than with a conventional
linkage setup.
Now for the flying part. Once I was happy
with how the airplane was trimmed, I flew
the 2007 IMAC Unlimited sequence. It felt
great, with a more locked feel than I had
ever experienced. At first I thought maybe it
was me, so I asked a few local club
members to fly my model. They all had the
same reaction.
The most interesting thing about the
field-testing was that after the guys went
back to flying their airplanes they noticed a
big difference between their linkage setups
and the Direct Drive. The first comment I
heard was that one pilot didn’t realize how
loose his model felt. He said he was going
to switch to Direct Drive on his next
airplane.
I’ve been flying my Carden aircraft with
the Durant Direct Drive system for a full
season. Well more than 100 flights are
logged on each.
I recommend this new design to anyone
who has a giant-scale model. The system is
ideal for aerobatic models because it offers
the most potential and smoothest operation
of a control surface, which is the goal of any
conscientious builder and aerobatic pilot.
I wasn’t sure about this new state-of-the-art
system at first, but now that I made the
switch I’ll never go back to the old linkage
system. The manufacturer is more than
happy to help and will answer any questions
that come up. The Web site has great
information about the setup and the history
behind Direct Drive. MA
Rick Byrd
[email protected]
Sources:
Futaba radio equipment
(800) 637-7660
www.futaba-rc.com
DuRant Direct Drive
(817) 243-8524
www.durantdirectdrive.com
Edition: Model Aviation - 2007/12
Page Numbers: 47,48,49,50
WHY DO WE have linkage systems? To
move the control surfaces to control a
model. What if there was an arrangement
that worked without a linkage system that
offered simple setup, minimal to zero slop,
precision, durability, and more
characteristics I look for in a system? I
believe there is!
A few years ago, at an International
Miniature Aerobatic Club (IMAC) contest
in Texas, I saw a direct-drive system that
got my attention. I could tell that it was
interesting and showed a great deal of
promise.
However, the system was so radically
different that I struggled to believe the
concept worked. I had been taught so
much about conventional linkage control
systems, how could a control system with
no pushrods, linkages, or control horns be
that good?
I asked the usual questions: how does it
work, is it easy to install, and how does it
feel in the air? I had several conversations
with John DuRant, the system’s designer,
and others who had made the switch. All
their comments were positive.
I flew an Ultimate and an Extra that were
set up with the DuRant Direct Drive. My
first thought was “Wow!” It felt like I was
connected to the airplane better than I had
ever been. The system not only provided a
simpler means of installation, but it offered
better performance. I decided to try it in my
next IMAC model.
Direct drive is about controlling the travel
of a moving surface without linkages, ball
links, or control arms—all slop and failure
points on an aircraft. The system is mounted
directly to the servo and the control surface.
That is ideal; before using the system I had
noticed a trend in control arms breaking at
the servo or at the surface.
I also like the idea of not losing the
mechanical advantage. With the extreme
control-surface throws required to set up a
model for 3-D, we tend to lose the
mechanical advantage for smooth precision
flying.
To have a model set up to do both 3-D
and precision had been a compromise; I had
never liked that idea, but it was the price to
pay for the 3-D thrill. With direct drive you
obtained an all-in-one flying setup for 3-D
and precision that would lose no control
fidelity. What more could you want?
I decided to test this control system in a
Carden Aircraft 37% YAK 54. I installed
the conventional two servos per wing
panel: one for each elevator half and three
for the rudder.
When the DuRant Direct Drive kit
arrived, the first thing I noticed was that the
entire system was laser-cut from plywood.
The servo boxes were designed with
interlocking sides, so they were easy to
assemble to be square and strong.
The included instructions were easy to
follow and informative. The Direct Drive
system can be installed in almost any Giant
Scale airplane and used with any servo,
regardless of size or make. The system is
available in a variety of sizes to make its
application as simple as possible.
To complete the setup the model must be
built with a removable hinge, a computer
radio, and a MatchBox or equivalent servo
wiring system. I used the Klett giant-scale
hinges since the pins are easy to remove and
install.
The mount boxes can be purchased in
single-, double-, and triple-servo
installations. I used the single installation on
every control surface except the rudder, for
which I used the triple-servo setup.
I went step by step and had no issues
along the way. Follow along with the
photos to see how the system is built into
the model.
I used the Futaba 14MZ radio system for
servo setup and programming. The whole
process was simple and went quickly since
48 MODEL AVIATION
Step 1. The tunnels for servo extensions have been located and
the control surfaces have been hinged.
Step 2. Assemble the servo box and mark its location on the
center of the flying-surface hinge line.
Step 3. After making pilot holes, use a
Dremel tool to rough-cut the outline of
the box frame.
Step 4. Clean out the rough opening and trim the area with an X-Acto knife so the box
will fit snugly. Keep the frame as square to the hinge line as possible.
Step 6. Carefully carve out the foam with
a hot-wire tool. Keep the tool as square
to the hinge line as possible.
Step 5. Make sure the box fits tightly inside the balsa TE cutout. Keep in mind that the
plywood box will reinforce the structure once it’s glued securely in place.
How the hole looks after you remove
the foam. The servo-wire tube should
be located at the inside corner.
Step 7. The box is glued
in using epoxy or Gorilla
Glue. Mark the control
surface for the relief cut
and control arm.
Photos by John DuRant and the author unless otherwise noted
December 2007 49
Step 8. A robust 1.5-inch servo arm is
mounted to a blank 1/16 plywood control
arm with cyanoacrylate and 4-40 hardware.
Step 9. Trim the control arm to fit the taper in the control surface. The fit should be
snug, and the length should match the inside dimensions of the control surface.
Step 10. Use the hot wire to slot the controlarm
socket. The center of the servo hole
must be on the center of the hinge line.
Step 11. The area that was cut out for the
relief can be reinforced using balsa sheeting.
Sand and cover the model as usual.
Step 12. Connect the servo to the arm.
Remember to center the servo with your
radio and then slide the servo into the box.
Multiple servos per control surface
are simple to install, and there are
no binding issues.
Step 13. Run the piano wire down
the hinge line, gap-seal the surface,
and the installation is complete.
The author’s Carden Aircraft 37% YAK 54 uses two
servos per aileron. The control system’s precision is
apparent to the pilot.
Three servos on
the rudder offer
maximum control
authority.
there were no linkages. Each servo took half
the time to install than with a conventional
linkage setup.
Now for the flying part. Once I was happy
with how the airplane was trimmed, I flew
the 2007 IMAC Unlimited sequence. It felt
great, with a more locked feel than I had
ever experienced. At first I thought maybe it
was me, so I asked a few local club
members to fly my model. They all had the
same reaction.
The most interesting thing about the
field-testing was that after the guys went
back to flying their airplanes they noticed a
big difference between their linkage setups
and the Direct Drive. The first comment I
heard was that one pilot didn’t realize how
loose his model felt. He said he was going
to switch to Direct Drive on his next
airplane.
I’ve been flying my Carden aircraft with
the Durant Direct Drive system for a full
season. Well more than 100 flights are
logged on each.
I recommend this new design to anyone
who has a giant-scale model. The system is
ideal for aerobatic models because it offers
the most potential and smoothest operation
of a control surface, which is the goal of any
conscientious builder and aerobatic pilot.
I wasn’t sure about this new state-of-the-art
system at first, but now that I made the
switch I’ll never go back to the old linkage
system. The manufacturer is more than
happy to help and will answer any questions
that come up. The Web site has great
information about the setup and the history
behind Direct Drive. MA
Rick Byrd
[email protected]
Sources:
Futaba radio equipment
(800) 637-7660
www.futaba-rc.com
DuRant Direct Drive
(817) 243-8524
www.durantdirectdrive.com
Edition: Model Aviation - 2007/12
Page Numbers: 47,48,49,50
WHY DO WE have linkage systems? To
move the control surfaces to control a
model. What if there was an arrangement
that worked without a linkage system that
offered simple setup, minimal to zero slop,
precision, durability, and more
characteristics I look for in a system? I
believe there is!
A few years ago, at an International
Miniature Aerobatic Club (IMAC) contest
in Texas, I saw a direct-drive system that
got my attention. I could tell that it was
interesting and showed a great deal of
promise.
However, the system was so radically
different that I struggled to believe the
concept worked. I had been taught so
much about conventional linkage control
systems, how could a control system with
no pushrods, linkages, or control horns be
that good?
I asked the usual questions: how does it
work, is it easy to install, and how does it
feel in the air? I had several conversations
with John DuRant, the system’s designer,
and others who had made the switch. All
their comments were positive.
I flew an Ultimate and an Extra that were
set up with the DuRant Direct Drive. My
first thought was “Wow!” It felt like I was
connected to the airplane better than I had
ever been. The system not only provided a
simpler means of installation, but it offered
better performance. I decided to try it in my
next IMAC model.
Direct drive is about controlling the travel
of a moving surface without linkages, ball
links, or control arms—all slop and failure
points on an aircraft. The system is mounted
directly to the servo and the control surface.
That is ideal; before using the system I had
noticed a trend in control arms breaking at
the servo or at the surface.
I also like the idea of not losing the
mechanical advantage. With the extreme
control-surface throws required to set up a
model for 3-D, we tend to lose the
mechanical advantage for smooth precision
flying.
To have a model set up to do both 3-D
and precision had been a compromise; I had
never liked that idea, but it was the price to
pay for the 3-D thrill. With direct drive you
obtained an all-in-one flying setup for 3-D
and precision that would lose no control
fidelity. What more could you want?
I decided to test this control system in a
Carden Aircraft 37% YAK 54. I installed
the conventional two servos per wing
panel: one for each elevator half and three
for the rudder.
When the DuRant Direct Drive kit
arrived, the first thing I noticed was that the
entire system was laser-cut from plywood.
The servo boxes were designed with
interlocking sides, so they were easy to
assemble to be square and strong.
The included instructions were easy to
follow and informative. The Direct Drive
system can be installed in almost any Giant
Scale airplane and used with any servo,
regardless of size or make. The system is
available in a variety of sizes to make its
application as simple as possible.
To complete the setup the model must be
built with a removable hinge, a computer
radio, and a MatchBox or equivalent servo
wiring system. I used the Klett giant-scale
hinges since the pins are easy to remove and
install.
The mount boxes can be purchased in
single-, double-, and triple-servo
installations. I used the single installation on
every control surface except the rudder, for
which I used the triple-servo setup.
I went step by step and had no issues
along the way. Follow along with the
photos to see how the system is built into
the model.
I used the Futaba 14MZ radio system for
servo setup and programming. The whole
process was simple and went quickly since
48 MODEL AVIATION
Step 1. The tunnels for servo extensions have been located and
the control surfaces have been hinged.
Step 2. Assemble the servo box and mark its location on the
center of the flying-surface hinge line.
Step 3. After making pilot holes, use a
Dremel tool to rough-cut the outline of
the box frame.
Step 4. Clean out the rough opening and trim the area with an X-Acto knife so the box
will fit snugly. Keep the frame as square to the hinge line as possible.
Step 6. Carefully carve out the foam with
a hot-wire tool. Keep the tool as square
to the hinge line as possible.
Step 5. Make sure the box fits tightly inside the balsa TE cutout. Keep in mind that the
plywood box will reinforce the structure once it’s glued securely in place.
How the hole looks after you remove
the foam. The servo-wire tube should
be located at the inside corner.
Step 7. The box is glued
in using epoxy or Gorilla
Glue. Mark the control
surface for the relief cut
and control arm.
Photos by John DuRant and the author unless otherwise noted
December 2007 49
Step 8. A robust 1.5-inch servo arm is
mounted to a blank 1/16 plywood control
arm with cyanoacrylate and 4-40 hardware.
Step 9. Trim the control arm to fit the taper in the control surface. The fit should be
snug, and the length should match the inside dimensions of the control surface.
Step 10. Use the hot wire to slot the controlarm
socket. The center of the servo hole
must be on the center of the hinge line.
Step 11. The area that was cut out for the
relief can be reinforced using balsa sheeting.
Sand and cover the model as usual.
Step 12. Connect the servo to the arm.
Remember to center the servo with your
radio and then slide the servo into the box.
Multiple servos per control surface
are simple to install, and there are
no binding issues.
Step 13. Run the piano wire down
the hinge line, gap-seal the surface,
and the installation is complete.
The author’s Carden Aircraft 37% YAK 54 uses two
servos per aileron. The control system’s precision is
apparent to the pilot.
Three servos on
the rudder offer
maximum control
authority.
there were no linkages. Each servo took half
the time to install than with a conventional
linkage setup.
Now for the flying part. Once I was happy
with how the airplane was trimmed, I flew
the 2007 IMAC Unlimited sequence. It felt
great, with a more locked feel than I had
ever experienced. At first I thought maybe it
was me, so I asked a few local club
members to fly my model. They all had the
same reaction.
The most interesting thing about the
field-testing was that after the guys went
back to flying their airplanes they noticed a
big difference between their linkage setups
and the Direct Drive. The first comment I
heard was that one pilot didn’t realize how
loose his model felt. He said he was going
to switch to Direct Drive on his next
airplane.
I’ve been flying my Carden aircraft with
the Durant Direct Drive system for a full
season. Well more than 100 flights are
logged on each.
I recommend this new design to anyone
who has a giant-scale model. The system is
ideal for aerobatic models because it offers
the most potential and smoothest operation
of a control surface, which is the goal of any
conscientious builder and aerobatic pilot.
I wasn’t sure about this new state-of-the-art
system at first, but now that I made the
switch I’ll never go back to the old linkage
system. The manufacturer is more than
happy to help and will answer any questions
that come up. The Web site has great
information about the setup and the history
behind Direct Drive. MA
Rick Byrd
[email protected]
Sources:
Futaba radio equipment
(800) 637-7660
www.futaba-rc.com
DuRant Direct Drive
(817) 243-8524
www.durantdirectdrive.com
