58 MODEL AVIATION
A 450-class
helicopter
with every
ANDY PANONCILLO
Swashplate: Assurance RC Align T-Rex 700 Nitro Pro
Probably the lightest 90-class helicopter kit on the market, this
machine is quick and can autorotate as if it were a glider.
The author demonstrates the model’s steady handling by hovering it less
than an inch above smooth pavement. William Ramsey waits his turn.
ROUGHLY A YEAR ago, Align released its flagship machine: the
T-Rex 700. There were mixed opinions about the helicopter, even
before it had been seen or flown. MA has given me the opportunity
to put one together and fly it for several months, to see how it
compares with other designs.
Construction: The kit comes neatly packaged, with well-labeled
parts. The instruction manual is laid out well, with step-by-step
illustrations showing how to put the components together.
The directions let the builder know which bag of parts is needed;
the bonus is that most parts in the bags arrive partially assembled.
The preassembled parts just need a going through with the
recommended thread-locking compound.
Both main rotor grips and the main rotor housing have a
streamlined design, yet they look strong enough to withstand the
most demanding maneuvers in 3-D flying. A critical step is
installing the thrust bearing the way it is labeled. Even the most
inexperienced builder won’t have a problem putting this kit together.
Align’s feathering shaft sleeve is one of the 700 head’s key
features that protects the dampener from extreme loads. Align made
sure that the spindle is ready for stress by using 6mm stock instead
of 4mm stock.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:50 AM Page 58
December 2009 59
Photos by the author and Michael Ramsey
The fan is efficient at cooling the power
system. The clutch has been updated since
this photo was taken.
O.S. got it right with the unpumped
version of the 91HZ. It’s easy to set the
needles and has gobs of power.
The lower frame plate does a great deal to
enhance the single-stacked carbon-fiber
frame’s rigidity.
Dental floss tied to the cotter pin security
system prevents the pins from being lost.
The kit’s organized parts bags are numbered and called out in the well-done instruction
manual. An aluminum and a carbon-fiber tailboom are included.
A Hatori muffler system is an outstanding complement to any helicopter. Shown is the
Bobby Watts Special, which offers a quiet exhaust note and oodles of power.
JR DS8717 servos were used on
the indirect cyclic controls. The
CCPM mechanics use a 120°
offset system.
Torque-drive transfer gears are robust,
with a key and pin mount system for
security. Plastic tail grips are lightweight.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 59
60 MODEL AVIATION
Test-Model Details
Engine used: O.S. 91HZ; Hatori SB-
20FH tuned muffler
Fuel: Byron Fuels Rotor Rage
Radio system: Spektrum DX7se
transmitter; AR7100R receiver;
Spartan DS760 gyro; JR DS8900G tail
servo; three JR DS8717 cyclic servos;
2400 mAh, 7.4-volt battery; Align
regulator; Align RCE-G600 Governor
Ready-to fly weight: 9.3 pounds
Flight duration: Eight to 10 minutes
Type: RC 90-class nitro-powered
helicopter
Rotor diameter: 61.50-63.07 inches
Tail-rotor diameter: 11.06 inches
Weight (without power system):
112.9 ounces
Length: 52.56 inches
Height: 17.72 inches
Engine: .91 cu. in. and muffler
Engine pinion gear: 20 teeth
Autorotation tail gear: 150 teeth
Gear ratio: 8.2:1:4.54
Construction: Single-stack carbonfiber
main frame
Control system: indirect CCPM
mechanics
Drive system: Two-stage main gear,
torque-tube tail control
Main rotor blades: 690mm-710mm
(not included)
Tailboom: Aluminum or carbon-fiber
tube with aluminum bracing
Canopy: Prepainted fiberglass
Fuel tank capacity: 630cc
Requires: Six- to eight-channel radio,
four servos, gyro, receiver battery
Price: $788.99
Specifications
Pluses and Minuses
+•
Simple, lightweight design provides
awesome flight performance.
• +/-13° collective pitch is possible for
extreme 3-D performance.
• Forward-mounted tail servo helps keep
exhaust oil from entering.
• Torque-tube-driven tail offers incredible
pirouette agility.
• Efficient airflow provides reliable engine
cooling and power. -•
Check the Web site for a new clutch
design. Replacing the original is worth it.
Spins and spirals are demanding tail-rotorauthority
maneuvers that this machine
handles extremely well. The head turns at
close to 2,150 rpm for 3-D.
Align’s 710mm 3-D blades are strong and
can handle the pops and stops of Tic-Toc
maneuvers.
Andy used Byron Rotor Rage fuel
throughout the six months of testing the
700. The engine’s insides still look new!
The vertical fin offers lots of protection against tail strikes. The T-Rex 700 is exceptionally
honest in cyclic control with little mixing noticed.
The one-piece 5mm x 24mm linkage
ball not only provides a stronger
connection, but it also contributes to the TRex
700’s overall build principle of having
a lower parts count. The metal seesaw,
flybar, and mixing arms are free and
smooth.
The swashplate is configured for 120°
cyclic/collective pitch mixing (CCPM)
geometry. Another feature I like is that the
washout base pin guides are against the
main shaft. This keeps the pins from
flexing away from the washout base.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 60
The main shaft is 12mm thick and
supports the head assembly with three M4
socket-head screws. One of the head
screws goes through the head block and
main shaft, and the other two lock against
the main shaft to prevent wobbling.
Following the success of the 600-class
clutch assembly, the 700 has a similar
design that features the clutch liner and
clutch gear preinstalled to the clutch bell.
The clutch bearing block securely holds
three bearings plus a fourth bearing in the
clutch bell. This assures smooth operation
of the power-transfer assembly.
With most of us using governors on
our helicopters for a more consistent rpm
during flight, Align has included the RCEG600.
The company has also designed the
clutch bell to hold two magnets for the
sensor, making it not only easy to install
but also simple to accurately locate the
sensor.
Assembling the carbon-fiber frame
begins with installing the metal tail
control arm, which is bolted against the
right-side frame using a frame-mounting
block. How much tail authority is
available to the pilot is obvious once this
block is in place. In addition, the assembly
itself is extremely smooth.
The left frame is where most of the
things pieced together earlier, but several
bolts/screws need to be left approximately
a half-turn loose for later alignment
purposes. The front and rear bottom frame
supports are doubled, because they also
locate the carbon bottom plate and landing
gear.
Notice that the main-shaft bearing
blocks are angled in a way that provides
more spacing between bearing blocks.
This is a carefully considered design
feature that offers a mechanical advantage
to the main shaft. Main machines employ
three bearings to support the main shaft,
but Align found that the two-bearing
design had less drag.
Use the outer opening of the tank to
install the clunk assembly. This way,
when you need to do a maintenance check
for possible leaks, it will be much easier
access than reaching between the frame
or, worse, having to take the tank off.
With the tank finished, you can join the
two carbon side frames.
At this point in the build, it is
recommended that you mount your engine
of choice. Before this, I prepped my O.S.
91HZ by installing the clutch, fan, and fan
shroud assembly.
The fan has a unique design that
increases its ability to take in air and, at
the same time, lower the load needed to
propel the fan itself. That is
complemented with the fan shroud interior
design, which provides a secondary fin to
redirect the air on the head and on the
engine case.
The main shaft is critical to the main
frame’s final alignment. Insert the shaft
through the two bearing blocks. Over a
flat surface, such as a glass table, make
sure the bottom frame is square against
the table. Ensure that the main shaft can
rotate and telescope smoothly before and
while you tighten the bearing blocks
against the frame.
This is also a good time to tighten the
clutch bearing-block screws against the
frame. While doing so, rotate the engine
several times and get a good feel of
freedom of the clutch against the start
shaft. Also do this while tightening the
engine against its mount.
The remainder of the frame assembly
is straightforward and easy. The T-Rex
700’s landing gear is identical to the TRex
600’s, only it’s white. The gear is
strong and provides just enough flex to
take the abuse of a hard landing.
The tailboom mount/block houses the
front gear drive assembly. I recommend
that you apply oil to the bearings, to
ensure smooth operation. I like the way
this piece locks onto the frame and ties
together the front gear drive assembly and
autorotation tail drive gear. The correct
gear mesh is assured.
The tail gearbox is also partially
preassembled. The metal pitch slider is
strong and smooth against the tail output
shaft. The specially designed tail-rotor
hub and the plastic tail grips that are on
the T-Rex 600 are also on the 700.
The tailboom self-aligns and locks
against the front boom block and to the
tail gearbox with the aid of the vertical
stabilizer mount. It includes a pin that
goes through the boom and gearbox.
With the two bearings glued against
the torque tube, rubber bearing holders
serve as dampening material for the
torque-tube assembly. Oil helps the two
rubber bearing holders fit more easily
inside the tailboom.
I recommend that you add a couple of
tail pushrod guides, making a total of five.
The additional pushrod support prevents
flexing, which will increase the gyro’s
effectiveness.
The overall build, including
photography, took only a day. The T-Rex
kit is a joy to assemble, and I believe that
even the most inexperienced helicopter
pilot could successfully build this
machine.
Reliability Test: Part of this review is to
see how the T-Rex 700 handles in flight
and, most important, how it will handle
after months of flying.
I’ve owned and flown several 90-size
helicopters from different manufacturers,
so I was interested in how this helicopter
would perform. Off the bench, it flew
smoothly and tracked straight both
upwind and downwind.
I noticed that the T-Rex 700 tended to
roll during forward flips, so I re-examined
my setup and made sure that the
swashplate stayed level in all collective
stick positions. I tweaked the model here
and there, retrimmed it for “flip-ability,”
and made sure that it tracked straight
during climbout right-side up and upsidedown.
After that bit of effort, the aircraft
flew better in all attitudes.
Its CG appears to be where it needs to
be, as evidenced by the helicopter’s
ability to roll smoothly along its axis. In
addition, the forward and backward flips
are easy to keep in one spot.
During the initial flights, it felt like I
needed to push the T-Rex 700 to fly
faster. But once I became accustomed to
its ability, I realized that it can carry
plenty of speed and perform maneuvers.
This machine can easily make a pilot look
skilled and doesn’t have the feeling of
being oversensitive.
Maintenance: Several screws needed to
be thread-locked again after the first
through fifth flights, which I consider
normal on a new helicopter. Six months
into flying it, I’ve replaced the head
dampener twice and gone through two
clutches. I also crashed the model twice.
Besides being easy to build, the T-Rex
700 is easy to repair and maintain. After
the first crash, I had to replace the
spindle, main shaft, front landing gear,
tailboom, and boom supports. The repair
took slightly more than an hour, which
meant that I could have gone back out to
fly it that afternoon.
There were rumors of ball links failing
during flight, but I still have the original
links on my model—and that’s flying in
the cold conditions here in Indiana. I also
flew the machine in the Philippines in
January and exposed those links to
extremely hot conditions.
Align started releasing parts that are
labeled “-1,” and one of the first was the
main gear. In six months of flying my TRex
700, I’ve replaced one main gear
because it stripped in flight. I’ve switched
back and forth between the older and new
main gear, and both types are holding up
fine.
The only part I’d consider replacing
from the start is the clutch, since I broke
two in flight. You can make this swap at
the field, so consider doing so before the
original part surprises you.
Align’s T-Rex 700 is well made and is
designed to keep the pilot flying. It’s
simple to construct, maintain, and fix, and
the model and parts are reasonably priced,
with hobby shop support almost
everywhere. What else could you want?
Align raised the bar and gave us
something we can likely afford, in
addition to the features I have mentioned.
I enjoyed this project so much that now I
have three T-Rex 700s—all ready to fly.
See you at the field! MA
Andy Panoncillo
[email protected]
Manufacturer/Distributor:
Align/Assurance RC USA
3626 Briggeman Dr.
Los Alamitos CA 90720
(562) 598-4700
www.alignusa.com
Sources:
Spektrum/JR
(800) 338-4639
www.horizonhobby.com
O.S. Engines
(217) 398-8970
www.osengines.com
Hatori USA:
Great Hobbies
(716) 297-3295
www.greathobbies.com
Spartan RC
+44 7092 862003
www.spartan-rc.com
Other Published Reviews:
None known at time of publication
Edition: Model Aviation - 2009/12
Page Numbers: 58,59,60,61,62
Edition: Model Aviation - 2009/12
Page Numbers: 58,59,60,61,62
58 MODEL AVIATION
A 450-class
helicopter
with every
ANDY PANONCILLO
Swashplate: Assurance RC Align T-Rex 700 Nitro Pro
Probably the lightest 90-class helicopter kit on the market, this
machine is quick and can autorotate as if it were a glider.
The author demonstrates the model’s steady handling by hovering it less
than an inch above smooth pavement. William Ramsey waits his turn.
ROUGHLY A YEAR ago, Align released its flagship machine: the
T-Rex 700. There were mixed opinions about the helicopter, even
before it had been seen or flown. MA has given me the opportunity
to put one together and fly it for several months, to see how it
compares with other designs.
Construction: The kit comes neatly packaged, with well-labeled
parts. The instruction manual is laid out well, with step-by-step
illustrations showing how to put the components together.
The directions let the builder know which bag of parts is needed;
the bonus is that most parts in the bags arrive partially assembled.
The preassembled parts just need a going through with the
recommended thread-locking compound.
Both main rotor grips and the main rotor housing have a
streamlined design, yet they look strong enough to withstand the
most demanding maneuvers in 3-D flying. A critical step is
installing the thrust bearing the way it is labeled. Even the most
inexperienced builder won’t have a problem putting this kit together.
Align’s feathering shaft sleeve is one of the 700 head’s key
features that protects the dampener from extreme loads. Align made
sure that the spindle is ready for stress by using 6mm stock instead
of 4mm stock.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:50 AM Page 58
December 2009 59
Photos by the author and Michael Ramsey
The fan is efficient at cooling the power
system. The clutch has been updated since
this photo was taken.
O.S. got it right with the unpumped
version of the 91HZ. It’s easy to set the
needles and has gobs of power.
The lower frame plate does a great deal to
enhance the single-stacked carbon-fiber
frame’s rigidity.
Dental floss tied to the cotter pin security
system prevents the pins from being lost.
The kit’s organized parts bags are numbered and called out in the well-done instruction
manual. An aluminum and a carbon-fiber tailboom are included.
A Hatori muffler system is an outstanding complement to any helicopter. Shown is the
Bobby Watts Special, which offers a quiet exhaust note and oodles of power.
JR DS8717 servos were used on
the indirect cyclic controls. The
CCPM mechanics use a 120°
offset system.
Torque-drive transfer gears are robust,
with a key and pin mount system for
security. Plastic tail grips are lightweight.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 59
60 MODEL AVIATION
Test-Model Details
Engine used: O.S. 91HZ; Hatori SB-
20FH tuned muffler
Fuel: Byron Fuels Rotor Rage
Radio system: Spektrum DX7se
transmitter; AR7100R receiver;
Spartan DS760 gyro; JR DS8900G tail
servo; three JR DS8717 cyclic servos;
2400 mAh, 7.4-volt battery; Align
regulator; Align RCE-G600 Governor
Ready-to fly weight: 9.3 pounds
Flight duration: Eight to 10 minutes
Type: RC 90-class nitro-powered
helicopter
Rotor diameter: 61.50-63.07 inches
Tail-rotor diameter: 11.06 inches
Weight (without power system):
112.9 ounces
Length: 52.56 inches
Height: 17.72 inches
Engine: .91 cu. in. and muffler
Engine pinion gear: 20 teeth
Autorotation tail gear: 150 teeth
Gear ratio: 8.2:1:4.54
Construction: Single-stack carbonfiber
main frame
Control system: indirect CCPM
mechanics
Drive system: Two-stage main gear,
torque-tube tail control
Main rotor blades: 690mm-710mm
(not included)
Tailboom: Aluminum or carbon-fiber
tube with aluminum bracing
Canopy: Prepainted fiberglass
Fuel tank capacity: 630cc
Requires: Six- to eight-channel radio,
four servos, gyro, receiver battery
Price: $788.99
Specifications
Pluses and Minuses
+•
Simple, lightweight design provides
awesome flight performance.
• +/-13° collective pitch is possible for
extreme 3-D performance.
• Forward-mounted tail servo helps keep
exhaust oil from entering.
• Torque-tube-driven tail offers incredible
pirouette agility.
• Efficient airflow provides reliable engine
cooling and power. -•
Check the Web site for a new clutch
design. Replacing the original is worth it.
Spins and spirals are demanding tail-rotorauthority
maneuvers that this machine
handles extremely well. The head turns at
close to 2,150 rpm for 3-D.
Align’s 710mm 3-D blades are strong and
can handle the pops and stops of Tic-Toc
maneuvers.
Andy used Byron Rotor Rage fuel
throughout the six months of testing the
700. The engine’s insides still look new!
The vertical fin offers lots of protection against tail strikes. The T-Rex 700 is exceptionally
honest in cyclic control with little mixing noticed.
The one-piece 5mm x 24mm linkage
ball not only provides a stronger
connection, but it also contributes to the TRex
700’s overall build principle of having
a lower parts count. The metal seesaw,
flybar, and mixing arms are free and
smooth.
The swashplate is configured for 120°
cyclic/collective pitch mixing (CCPM)
geometry. Another feature I like is that the
washout base pin guides are against the
main shaft. This keeps the pins from
flexing away from the washout base.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 60
The main shaft is 12mm thick and
supports the head assembly with three M4
socket-head screws. One of the head
screws goes through the head block and
main shaft, and the other two lock against
the main shaft to prevent wobbling.
Following the success of the 600-class
clutch assembly, the 700 has a similar
design that features the clutch liner and
clutch gear preinstalled to the clutch bell.
The clutch bearing block securely holds
three bearings plus a fourth bearing in the
clutch bell. This assures smooth operation
of the power-transfer assembly.
With most of us using governors on
our helicopters for a more consistent rpm
during flight, Align has included the RCEG600.
The company has also designed the
clutch bell to hold two magnets for the
sensor, making it not only easy to install
but also simple to accurately locate the
sensor.
Assembling the carbon-fiber frame
begins with installing the metal tail
control arm, which is bolted against the
right-side frame using a frame-mounting
block. How much tail authority is
available to the pilot is obvious once this
block is in place. In addition, the assembly
itself is extremely smooth.
The left frame is where most of the
things pieced together earlier, but several
bolts/screws need to be left approximately
a half-turn loose for later alignment
purposes. The front and rear bottom frame
supports are doubled, because they also
locate the carbon bottom plate and landing
gear.
Notice that the main-shaft bearing
blocks are angled in a way that provides
more spacing between bearing blocks.
This is a carefully considered design
feature that offers a mechanical advantage
to the main shaft. Main machines employ
three bearings to support the main shaft,
but Align found that the two-bearing
design had less drag.
Use the outer opening of the tank to
install the clunk assembly. This way,
when you need to do a maintenance check
for possible leaks, it will be much easier
access than reaching between the frame
or, worse, having to take the tank off.
With the tank finished, you can join the
two carbon side frames.
At this point in the build, it is
recommended that you mount your engine
of choice. Before this, I prepped my O.S.
91HZ by installing the clutch, fan, and fan
shroud assembly.
The fan has a unique design that
increases its ability to take in air and, at
the same time, lower the load needed to
propel the fan itself. That is
complemented with the fan shroud interior
design, which provides a secondary fin to
redirect the air on the head and on the
engine case.
The main shaft is critical to the main
frame’s final alignment. Insert the shaft
through the two bearing blocks. Over a
flat surface, such as a glass table, make
sure the bottom frame is square against
the table. Ensure that the main shaft can
rotate and telescope smoothly before and
while you tighten the bearing blocks
against the frame.
This is also a good time to tighten the
clutch bearing-block screws against the
frame. While doing so, rotate the engine
several times and get a good feel of
freedom of the clutch against the start
shaft. Also do this while tightening the
engine against its mount.
The remainder of the frame assembly
is straightforward and easy. The T-Rex
700’s landing gear is identical to the TRex
600’s, only it’s white. The gear is
strong and provides just enough flex to
take the abuse of a hard landing.
The tailboom mount/block houses the
front gear drive assembly. I recommend
that you apply oil to the bearings, to
ensure smooth operation. I like the way
this piece locks onto the frame and ties
together the front gear drive assembly and
autorotation tail drive gear. The correct
gear mesh is assured.
The tail gearbox is also partially
preassembled. The metal pitch slider is
strong and smooth against the tail output
shaft. The specially designed tail-rotor
hub and the plastic tail grips that are on
the T-Rex 600 are also on the 700.
The tailboom self-aligns and locks
against the front boom block and to the
tail gearbox with the aid of the vertical
stabilizer mount. It includes a pin that
goes through the boom and gearbox.
With the two bearings glued against
the torque tube, rubber bearing holders
serve as dampening material for the
torque-tube assembly. Oil helps the two
rubber bearing holders fit more easily
inside the tailboom.
I recommend that you add a couple of
tail pushrod guides, making a total of five.
The additional pushrod support prevents
flexing, which will increase the gyro’s
effectiveness.
The overall build, including
photography, took only a day. The T-Rex
kit is a joy to assemble, and I believe that
even the most inexperienced helicopter
pilot could successfully build this
machine.
Reliability Test: Part of this review is to
see how the T-Rex 700 handles in flight
and, most important, how it will handle
after months of flying.
I’ve owned and flown several 90-size
helicopters from different manufacturers,
so I was interested in how this helicopter
would perform. Off the bench, it flew
smoothly and tracked straight both
upwind and downwind.
I noticed that the T-Rex 700 tended to
roll during forward flips, so I re-examined
my setup and made sure that the
swashplate stayed level in all collective
stick positions. I tweaked the model here
and there, retrimmed it for “flip-ability,”
and made sure that it tracked straight
during climbout right-side up and upsidedown.
After that bit of effort, the aircraft
flew better in all attitudes.
Its CG appears to be where it needs to
be, as evidenced by the helicopter’s
ability to roll smoothly along its axis. In
addition, the forward and backward flips
are easy to keep in one spot.
During the initial flights, it felt like I
needed to push the T-Rex 700 to fly
faster. But once I became accustomed to
its ability, I realized that it can carry
plenty of speed and perform maneuvers.
This machine can easily make a pilot look
skilled and doesn’t have the feeling of
being oversensitive.
Maintenance: Several screws needed to
be thread-locked again after the first
through fifth flights, which I consider
normal on a new helicopter. Six months
into flying it, I’ve replaced the head
dampener twice and gone through two
clutches. I also crashed the model twice.
Besides being easy to build, the T-Rex
700 is easy to repair and maintain. After
the first crash, I had to replace the
spindle, main shaft, front landing gear,
tailboom, and boom supports. The repair
took slightly more than an hour, which
meant that I could have gone back out to
fly it that afternoon.
There were rumors of ball links failing
during flight, but I still have the original
links on my model—and that’s flying in
the cold conditions here in Indiana. I also
flew the machine in the Philippines in
January and exposed those links to
extremely hot conditions.
Align started releasing parts that are
labeled “-1,” and one of the first was the
main gear. In six months of flying my TRex
700, I’ve replaced one main gear
because it stripped in flight. I’ve switched
back and forth between the older and new
main gear, and both types are holding up
fine.
The only part I’d consider replacing
from the start is the clutch, since I broke
two in flight. You can make this swap at
the field, so consider doing so before the
original part surprises you.
Align’s T-Rex 700 is well made and is
designed to keep the pilot flying. It’s
simple to construct, maintain, and fix, and
the model and parts are reasonably priced,
with hobby shop support almost
everywhere. What else could you want?
Align raised the bar and gave us
something we can likely afford, in
addition to the features I have mentioned.
I enjoyed this project so much that now I
have three T-Rex 700s—all ready to fly.
See you at the field! MA
Andy Panoncillo
[email protected]
Manufacturer/Distributor:
Align/Assurance RC USA
3626 Briggeman Dr.
Los Alamitos CA 90720
(562) 598-4700
www.alignusa.com
Sources:
Spektrum/JR
(800) 338-4639
www.horizonhobby.com
O.S. Engines
(217) 398-8970
www.osengines.com
Hatori USA:
Great Hobbies
(716) 297-3295
www.greathobbies.com
Spartan RC
+44 7092 862003
www.spartan-rc.com
Other Published Reviews:
None known at time of publication
Edition: Model Aviation - 2009/12
Page Numbers: 58,59,60,61,62
58 MODEL AVIATION
A 450-class
helicopter
with every
ANDY PANONCILLO
Swashplate: Assurance RC Align T-Rex 700 Nitro Pro
Probably the lightest 90-class helicopter kit on the market, this
machine is quick and can autorotate as if it were a glider.
The author demonstrates the model’s steady handling by hovering it less
than an inch above smooth pavement. William Ramsey waits his turn.
ROUGHLY A YEAR ago, Align released its flagship machine: the
T-Rex 700. There were mixed opinions about the helicopter, even
before it had been seen or flown. MA has given me the opportunity
to put one together and fly it for several months, to see how it
compares with other designs.
Construction: The kit comes neatly packaged, with well-labeled
parts. The instruction manual is laid out well, with step-by-step
illustrations showing how to put the components together.
The directions let the builder know which bag of parts is needed;
the bonus is that most parts in the bags arrive partially assembled.
The preassembled parts just need a going through with the
recommended thread-locking compound.
Both main rotor grips and the main rotor housing have a
streamlined design, yet they look strong enough to withstand the
most demanding maneuvers in 3-D flying. A critical step is
installing the thrust bearing the way it is labeled. Even the most
inexperienced builder won’t have a problem putting this kit together.
Align’s feathering shaft sleeve is one of the 700 head’s key
features that protects the dampener from extreme loads. Align made
sure that the spindle is ready for stress by using 6mm stock instead
of 4mm stock.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:50 AM Page 58
December 2009 59
Photos by the author and Michael Ramsey
The fan is efficient at cooling the power
system. The clutch has been updated since
this photo was taken.
O.S. got it right with the unpumped
version of the 91HZ. It’s easy to set the
needles and has gobs of power.
The lower frame plate does a great deal to
enhance the single-stacked carbon-fiber
frame’s rigidity.
Dental floss tied to the cotter pin security
system prevents the pins from being lost.
The kit’s organized parts bags are numbered and called out in the well-done instruction
manual. An aluminum and a carbon-fiber tailboom are included.
A Hatori muffler system is an outstanding complement to any helicopter. Shown is the
Bobby Watts Special, which offers a quiet exhaust note and oodles of power.
JR DS8717 servos were used on
the indirect cyclic controls. The
CCPM mechanics use a 120°
offset system.
Torque-drive transfer gears are robust,
with a key and pin mount system for
security. Plastic tail grips are lightweight.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 59
60 MODEL AVIATION
Test-Model Details
Engine used: O.S. 91HZ; Hatori SB-
20FH tuned muffler
Fuel: Byron Fuels Rotor Rage
Radio system: Spektrum DX7se
transmitter; AR7100R receiver;
Spartan DS760 gyro; JR DS8900G tail
servo; three JR DS8717 cyclic servos;
2400 mAh, 7.4-volt battery; Align
regulator; Align RCE-G600 Governor
Ready-to fly weight: 9.3 pounds
Flight duration: Eight to 10 minutes
Type: RC 90-class nitro-powered
helicopter
Rotor diameter: 61.50-63.07 inches
Tail-rotor diameter: 11.06 inches
Weight (without power system):
112.9 ounces
Length: 52.56 inches
Height: 17.72 inches
Engine: .91 cu. in. and muffler
Engine pinion gear: 20 teeth
Autorotation tail gear: 150 teeth
Gear ratio: 8.2:1:4.54
Construction: Single-stack carbonfiber
main frame
Control system: indirect CCPM
mechanics
Drive system: Two-stage main gear,
torque-tube tail control
Main rotor blades: 690mm-710mm
(not included)
Tailboom: Aluminum or carbon-fiber
tube with aluminum bracing
Canopy: Prepainted fiberglass
Fuel tank capacity: 630cc
Requires: Six- to eight-channel radio,
four servos, gyro, receiver battery
Price: $788.99
Specifications
Pluses and Minuses
+•
Simple, lightweight design provides
awesome flight performance.
• +/-13° collective pitch is possible for
extreme 3-D performance.
• Forward-mounted tail servo helps keep
exhaust oil from entering.
• Torque-tube-driven tail offers incredible
pirouette agility.
• Efficient airflow provides reliable engine
cooling and power. -•
Check the Web site for a new clutch
design. Replacing the original is worth it.
Spins and spirals are demanding tail-rotorauthority
maneuvers that this machine
handles extremely well. The head turns at
close to 2,150 rpm for 3-D.
Align’s 710mm 3-D blades are strong and
can handle the pops and stops of Tic-Toc
maneuvers.
Andy used Byron Rotor Rage fuel
throughout the six months of testing the
700. The engine’s insides still look new!
The vertical fin offers lots of protection against tail strikes. The T-Rex 700 is exceptionally
honest in cyclic control with little mixing noticed.
The one-piece 5mm x 24mm linkage
ball not only provides a stronger
connection, but it also contributes to the TRex
700’s overall build principle of having
a lower parts count. The metal seesaw,
flybar, and mixing arms are free and
smooth.
The swashplate is configured for 120°
cyclic/collective pitch mixing (CCPM)
geometry. Another feature I like is that the
washout base pin guides are against the
main shaft. This keeps the pins from
flexing away from the washout base.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 60
The main shaft is 12mm thick and
supports the head assembly with three M4
socket-head screws. One of the head
screws goes through the head block and
main shaft, and the other two lock against
the main shaft to prevent wobbling.
Following the success of the 600-class
clutch assembly, the 700 has a similar
design that features the clutch liner and
clutch gear preinstalled to the clutch bell.
The clutch bearing block securely holds
three bearings plus a fourth bearing in the
clutch bell. This assures smooth operation
of the power-transfer assembly.
With most of us using governors on
our helicopters for a more consistent rpm
during flight, Align has included the RCEG600.
The company has also designed the
clutch bell to hold two magnets for the
sensor, making it not only easy to install
but also simple to accurately locate the
sensor.
Assembling the carbon-fiber frame
begins with installing the metal tail
control arm, which is bolted against the
right-side frame using a frame-mounting
block. How much tail authority is
available to the pilot is obvious once this
block is in place. In addition, the assembly
itself is extremely smooth.
The left frame is where most of the
things pieced together earlier, but several
bolts/screws need to be left approximately
a half-turn loose for later alignment
purposes. The front and rear bottom frame
supports are doubled, because they also
locate the carbon bottom plate and landing
gear.
Notice that the main-shaft bearing
blocks are angled in a way that provides
more spacing between bearing blocks.
This is a carefully considered design
feature that offers a mechanical advantage
to the main shaft. Main machines employ
three bearings to support the main shaft,
but Align found that the two-bearing
design had less drag.
Use the outer opening of the tank to
install the clunk assembly. This way,
when you need to do a maintenance check
for possible leaks, it will be much easier
access than reaching between the frame
or, worse, having to take the tank off.
With the tank finished, you can join the
two carbon side frames.
At this point in the build, it is
recommended that you mount your engine
of choice. Before this, I prepped my O.S.
91HZ by installing the clutch, fan, and fan
shroud assembly.
The fan has a unique design that
increases its ability to take in air and, at
the same time, lower the load needed to
propel the fan itself. That is
complemented with the fan shroud interior
design, which provides a secondary fin to
redirect the air on the head and on the
engine case.
The main shaft is critical to the main
frame’s final alignment. Insert the shaft
through the two bearing blocks. Over a
flat surface, such as a glass table, make
sure the bottom frame is square against
the table. Ensure that the main shaft can
rotate and telescope smoothly before and
while you tighten the bearing blocks
against the frame.
This is also a good time to tighten the
clutch bearing-block screws against the
frame. While doing so, rotate the engine
several times and get a good feel of
freedom of the clutch against the start
shaft. Also do this while tightening the
engine against its mount.
The remainder of the frame assembly
is straightforward and easy. The T-Rex
700’s landing gear is identical to the TRex
600’s, only it’s white. The gear is
strong and provides just enough flex to
take the abuse of a hard landing.
The tailboom mount/block houses the
front gear drive assembly. I recommend
that you apply oil to the bearings, to
ensure smooth operation. I like the way
this piece locks onto the frame and ties
together the front gear drive assembly and
autorotation tail drive gear. The correct
gear mesh is assured.
The tail gearbox is also partially
preassembled. The metal pitch slider is
strong and smooth against the tail output
shaft. The specially designed tail-rotor
hub and the plastic tail grips that are on
the T-Rex 600 are also on the 700.
The tailboom self-aligns and locks
against the front boom block and to the
tail gearbox with the aid of the vertical
stabilizer mount. It includes a pin that
goes through the boom and gearbox.
With the two bearings glued against
the torque tube, rubber bearing holders
serve as dampening material for the
torque-tube assembly. Oil helps the two
rubber bearing holders fit more easily
inside the tailboom.
I recommend that you add a couple of
tail pushrod guides, making a total of five.
The additional pushrod support prevents
flexing, which will increase the gyro’s
effectiveness.
The overall build, including
photography, took only a day. The T-Rex
kit is a joy to assemble, and I believe that
even the most inexperienced helicopter
pilot could successfully build this
machine.
Reliability Test: Part of this review is to
see how the T-Rex 700 handles in flight
and, most important, how it will handle
after months of flying.
I’ve owned and flown several 90-size
helicopters from different manufacturers,
so I was interested in how this helicopter
would perform. Off the bench, it flew
smoothly and tracked straight both
upwind and downwind.
I noticed that the T-Rex 700 tended to
roll during forward flips, so I re-examined
my setup and made sure that the
swashplate stayed level in all collective
stick positions. I tweaked the model here
and there, retrimmed it for “flip-ability,”
and made sure that it tracked straight
during climbout right-side up and upsidedown.
After that bit of effort, the aircraft
flew better in all attitudes.
Its CG appears to be where it needs to
be, as evidenced by the helicopter’s
ability to roll smoothly along its axis. In
addition, the forward and backward flips
are easy to keep in one spot.
During the initial flights, it felt like I
needed to push the T-Rex 700 to fly
faster. But once I became accustomed to
its ability, I realized that it can carry
plenty of speed and perform maneuvers.
This machine can easily make a pilot look
skilled and doesn’t have the feeling of
being oversensitive.
Maintenance: Several screws needed to
be thread-locked again after the first
through fifth flights, which I consider
normal on a new helicopter. Six months
into flying it, I’ve replaced the head
dampener twice and gone through two
clutches. I also crashed the model twice.
Besides being easy to build, the T-Rex
700 is easy to repair and maintain. After
the first crash, I had to replace the
spindle, main shaft, front landing gear,
tailboom, and boom supports. The repair
took slightly more than an hour, which
meant that I could have gone back out to
fly it that afternoon.
There were rumors of ball links failing
during flight, but I still have the original
links on my model—and that’s flying in
the cold conditions here in Indiana. I also
flew the machine in the Philippines in
January and exposed those links to
extremely hot conditions.
Align started releasing parts that are
labeled “-1,” and one of the first was the
main gear. In six months of flying my TRex
700, I’ve replaced one main gear
because it stripped in flight. I’ve switched
back and forth between the older and new
main gear, and both types are holding up
fine.
The only part I’d consider replacing
from the start is the clutch, since I broke
two in flight. You can make this swap at
the field, so consider doing so before the
original part surprises you.
Align’s T-Rex 700 is well made and is
designed to keep the pilot flying. It’s
simple to construct, maintain, and fix, and
the model and parts are reasonably priced,
with hobby shop support almost
everywhere. What else could you want?
Align raised the bar and gave us
something we can likely afford, in
addition to the features I have mentioned.
I enjoyed this project so much that now I
have three T-Rex 700s—all ready to fly.
See you at the field! MA
Andy Panoncillo
[email protected]
Manufacturer/Distributor:
Align/Assurance RC USA
3626 Briggeman Dr.
Los Alamitos CA 90720
(562) 598-4700
www.alignusa.com
Sources:
Spektrum/JR
(800) 338-4639
www.horizonhobby.com
O.S. Engines
(217) 398-8970
www.osengines.com
Hatori USA:
Great Hobbies
(716) 297-3295
www.greathobbies.com
Spartan RC
+44 7092 862003
www.spartan-rc.com
Other Published Reviews:
None known at time of publication
Edition: Model Aviation - 2009/12
Page Numbers: 58,59,60,61,62
58 MODEL AVIATION
A 450-class
helicopter
with every
ANDY PANONCILLO
Swashplate: Assurance RC Align T-Rex 700 Nitro Pro
Probably the lightest 90-class helicopter kit on the market, this
machine is quick and can autorotate as if it were a glider.
The author demonstrates the model’s steady handling by hovering it less
than an inch above smooth pavement. William Ramsey waits his turn.
ROUGHLY A YEAR ago, Align released its flagship machine: the
T-Rex 700. There were mixed opinions about the helicopter, even
before it had been seen or flown. MA has given me the opportunity
to put one together and fly it for several months, to see how it
compares with other designs.
Construction: The kit comes neatly packaged, with well-labeled
parts. The instruction manual is laid out well, with step-by-step
illustrations showing how to put the components together.
The directions let the builder know which bag of parts is needed;
the bonus is that most parts in the bags arrive partially assembled.
The preassembled parts just need a going through with the
recommended thread-locking compound.
Both main rotor grips and the main rotor housing have a
streamlined design, yet they look strong enough to withstand the
most demanding maneuvers in 3-D flying. A critical step is
installing the thrust bearing the way it is labeled. Even the most
inexperienced builder won’t have a problem putting this kit together.
Align’s feathering shaft sleeve is one of the 700 head’s key
features that protects the dampener from extreme loads. Align made
sure that the spindle is ready for stress by using 6mm stock instead
of 4mm stock.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:50 AM Page 58
December 2009 59
Photos by the author and Michael Ramsey
The fan is efficient at cooling the power
system. The clutch has been updated since
this photo was taken.
O.S. got it right with the unpumped
version of the 91HZ. It’s easy to set the
needles and has gobs of power.
The lower frame plate does a great deal to
enhance the single-stacked carbon-fiber
frame’s rigidity.
Dental floss tied to the cotter pin security
system prevents the pins from being lost.
The kit’s organized parts bags are numbered and called out in the well-done instruction
manual. An aluminum and a carbon-fiber tailboom are included.
A Hatori muffler system is an outstanding complement to any helicopter. Shown is the
Bobby Watts Special, which offers a quiet exhaust note and oodles of power.
JR DS8717 servos were used on
the indirect cyclic controls. The
CCPM mechanics use a 120°
offset system.
Torque-drive transfer gears are robust,
with a key and pin mount system for
security. Plastic tail grips are lightweight.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 59
60 MODEL AVIATION
Test-Model Details
Engine used: O.S. 91HZ; Hatori SB-
20FH tuned muffler
Fuel: Byron Fuels Rotor Rage
Radio system: Spektrum DX7se
transmitter; AR7100R receiver;
Spartan DS760 gyro; JR DS8900G tail
servo; three JR DS8717 cyclic servos;
2400 mAh, 7.4-volt battery; Align
regulator; Align RCE-G600 Governor
Ready-to fly weight: 9.3 pounds
Flight duration: Eight to 10 minutes
Type: RC 90-class nitro-powered
helicopter
Rotor diameter: 61.50-63.07 inches
Tail-rotor diameter: 11.06 inches
Weight (without power system):
112.9 ounces
Length: 52.56 inches
Height: 17.72 inches
Engine: .91 cu. in. and muffler
Engine pinion gear: 20 teeth
Autorotation tail gear: 150 teeth
Gear ratio: 8.2:1:4.54
Construction: Single-stack carbonfiber
main frame
Control system: indirect CCPM
mechanics
Drive system: Two-stage main gear,
torque-tube tail control
Main rotor blades: 690mm-710mm
(not included)
Tailboom: Aluminum or carbon-fiber
tube with aluminum bracing
Canopy: Prepainted fiberglass
Fuel tank capacity: 630cc
Requires: Six- to eight-channel radio,
four servos, gyro, receiver battery
Price: $788.99
Specifications
Pluses and Minuses
+•
Simple, lightweight design provides
awesome flight performance.
• +/-13° collective pitch is possible for
extreme 3-D performance.
• Forward-mounted tail servo helps keep
exhaust oil from entering.
• Torque-tube-driven tail offers incredible
pirouette agility.
• Efficient airflow provides reliable engine
cooling and power. -•
Check the Web site for a new clutch
design. Replacing the original is worth it.
Spins and spirals are demanding tail-rotorauthority
maneuvers that this machine
handles extremely well. The head turns at
close to 2,150 rpm for 3-D.
Align’s 710mm 3-D blades are strong and
can handle the pops and stops of Tic-Toc
maneuvers.
Andy used Byron Rotor Rage fuel
throughout the six months of testing the
700. The engine’s insides still look new!
The vertical fin offers lots of protection against tail strikes. The T-Rex 700 is exceptionally
honest in cyclic control with little mixing noticed.
The one-piece 5mm x 24mm linkage
ball not only provides a stronger
connection, but it also contributes to the TRex
700’s overall build principle of having
a lower parts count. The metal seesaw,
flybar, and mixing arms are free and
smooth.
The swashplate is configured for 120°
cyclic/collective pitch mixing (CCPM)
geometry. Another feature I like is that the
washout base pin guides are against the
main shaft. This keeps the pins from
flexing away from the washout base.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 60
The main shaft is 12mm thick and
supports the head assembly with three M4
socket-head screws. One of the head
screws goes through the head block and
main shaft, and the other two lock against
the main shaft to prevent wobbling.
Following the success of the 600-class
clutch assembly, the 700 has a similar
design that features the clutch liner and
clutch gear preinstalled to the clutch bell.
The clutch bearing block securely holds
three bearings plus a fourth bearing in the
clutch bell. This assures smooth operation
of the power-transfer assembly.
With most of us using governors on
our helicopters for a more consistent rpm
during flight, Align has included the RCEG600.
The company has also designed the
clutch bell to hold two magnets for the
sensor, making it not only easy to install
but also simple to accurately locate the
sensor.
Assembling the carbon-fiber frame
begins with installing the metal tail
control arm, which is bolted against the
right-side frame using a frame-mounting
block. How much tail authority is
available to the pilot is obvious once this
block is in place. In addition, the assembly
itself is extremely smooth.
The left frame is where most of the
things pieced together earlier, but several
bolts/screws need to be left approximately
a half-turn loose for later alignment
purposes. The front and rear bottom frame
supports are doubled, because they also
locate the carbon bottom plate and landing
gear.
Notice that the main-shaft bearing
blocks are angled in a way that provides
more spacing between bearing blocks.
This is a carefully considered design
feature that offers a mechanical advantage
to the main shaft. Main machines employ
three bearings to support the main shaft,
but Align found that the two-bearing
design had less drag.
Use the outer opening of the tank to
install the clunk assembly. This way,
when you need to do a maintenance check
for possible leaks, it will be much easier
access than reaching between the frame
or, worse, having to take the tank off.
With the tank finished, you can join the
two carbon side frames.
At this point in the build, it is
recommended that you mount your engine
of choice. Before this, I prepped my O.S.
91HZ by installing the clutch, fan, and fan
shroud assembly.
The fan has a unique design that
increases its ability to take in air and, at
the same time, lower the load needed to
propel the fan itself. That is
complemented with the fan shroud interior
design, which provides a secondary fin to
redirect the air on the head and on the
engine case.
The main shaft is critical to the main
frame’s final alignment. Insert the shaft
through the two bearing blocks. Over a
flat surface, such as a glass table, make
sure the bottom frame is square against
the table. Ensure that the main shaft can
rotate and telescope smoothly before and
while you tighten the bearing blocks
against the frame.
This is also a good time to tighten the
clutch bearing-block screws against the
frame. While doing so, rotate the engine
several times and get a good feel of
freedom of the clutch against the start
shaft. Also do this while tightening the
engine against its mount.
The remainder of the frame assembly
is straightforward and easy. The T-Rex
700’s landing gear is identical to the TRex
600’s, only it’s white. The gear is
strong and provides just enough flex to
take the abuse of a hard landing.
The tailboom mount/block houses the
front gear drive assembly. I recommend
that you apply oil to the bearings, to
ensure smooth operation. I like the way
this piece locks onto the frame and ties
together the front gear drive assembly and
autorotation tail drive gear. The correct
gear mesh is assured.
The tail gearbox is also partially
preassembled. The metal pitch slider is
strong and smooth against the tail output
shaft. The specially designed tail-rotor
hub and the plastic tail grips that are on
the T-Rex 600 are also on the 700.
The tailboom self-aligns and locks
against the front boom block and to the
tail gearbox with the aid of the vertical
stabilizer mount. It includes a pin that
goes through the boom and gearbox.
With the two bearings glued against
the torque tube, rubber bearing holders
serve as dampening material for the
torque-tube assembly. Oil helps the two
rubber bearing holders fit more easily
inside the tailboom.
I recommend that you add a couple of
tail pushrod guides, making a total of five.
The additional pushrod support prevents
flexing, which will increase the gyro’s
effectiveness.
The overall build, including
photography, took only a day. The T-Rex
kit is a joy to assemble, and I believe that
even the most inexperienced helicopter
pilot could successfully build this
machine.
Reliability Test: Part of this review is to
see how the T-Rex 700 handles in flight
and, most important, how it will handle
after months of flying.
I’ve owned and flown several 90-size
helicopters from different manufacturers,
so I was interested in how this helicopter
would perform. Off the bench, it flew
smoothly and tracked straight both
upwind and downwind.
I noticed that the T-Rex 700 tended to
roll during forward flips, so I re-examined
my setup and made sure that the
swashplate stayed level in all collective
stick positions. I tweaked the model here
and there, retrimmed it for “flip-ability,”
and made sure that it tracked straight
during climbout right-side up and upsidedown.
After that bit of effort, the aircraft
flew better in all attitudes.
Its CG appears to be where it needs to
be, as evidenced by the helicopter’s
ability to roll smoothly along its axis. In
addition, the forward and backward flips
are easy to keep in one spot.
During the initial flights, it felt like I
needed to push the T-Rex 700 to fly
faster. But once I became accustomed to
its ability, I realized that it can carry
plenty of speed and perform maneuvers.
This machine can easily make a pilot look
skilled and doesn’t have the feeling of
being oversensitive.
Maintenance: Several screws needed to
be thread-locked again after the first
through fifth flights, which I consider
normal on a new helicopter. Six months
into flying it, I’ve replaced the head
dampener twice and gone through two
clutches. I also crashed the model twice.
Besides being easy to build, the T-Rex
700 is easy to repair and maintain. After
the first crash, I had to replace the
spindle, main shaft, front landing gear,
tailboom, and boom supports. The repair
took slightly more than an hour, which
meant that I could have gone back out to
fly it that afternoon.
There were rumors of ball links failing
during flight, but I still have the original
links on my model—and that’s flying in
the cold conditions here in Indiana. I also
flew the machine in the Philippines in
January and exposed those links to
extremely hot conditions.
Align started releasing parts that are
labeled “-1,” and one of the first was the
main gear. In six months of flying my TRex
700, I’ve replaced one main gear
because it stripped in flight. I’ve switched
back and forth between the older and new
main gear, and both types are holding up
fine.
The only part I’d consider replacing
from the start is the clutch, since I broke
two in flight. You can make this swap at
the field, so consider doing so before the
original part surprises you.
Align’s T-Rex 700 is well made and is
designed to keep the pilot flying. It’s
simple to construct, maintain, and fix, and
the model and parts are reasonably priced,
with hobby shop support almost
everywhere. What else could you want?
Align raised the bar and gave us
something we can likely afford, in
addition to the features I have mentioned.
I enjoyed this project so much that now I
have three T-Rex 700s—all ready to fly.
See you at the field! MA
Andy Panoncillo
[email protected]
Manufacturer/Distributor:
Align/Assurance RC USA
3626 Briggeman Dr.
Los Alamitos CA 90720
(562) 598-4700
www.alignusa.com
Sources:
Spektrum/JR
(800) 338-4639
www.horizonhobby.com
O.S. Engines
(217) 398-8970
www.osengines.com
Hatori USA:
Great Hobbies
(716) 297-3295
www.greathobbies.com
Spartan RC
+44 7092 862003
www.spartan-rc.com
Other Published Reviews:
None known at time of publication
Edition: Model Aviation - 2009/12
Page Numbers: 58,59,60,61,62
58 MODEL AVIATION
A 450-class
helicopter
with every
ANDY PANONCILLO
Swashplate: Assurance RC Align T-Rex 700 Nitro Pro
Probably the lightest 90-class helicopter kit on the market, this
machine is quick and can autorotate as if it were a glider.
The author demonstrates the model’s steady handling by hovering it less
than an inch above smooth pavement. William Ramsey waits his turn.
ROUGHLY A YEAR ago, Align released its flagship machine: the
T-Rex 700. There were mixed opinions about the helicopter, even
before it had been seen or flown. MA has given me the opportunity
to put one together and fly it for several months, to see how it
compares with other designs.
Construction: The kit comes neatly packaged, with well-labeled
parts. The instruction manual is laid out well, with step-by-step
illustrations showing how to put the components together.
The directions let the builder know which bag of parts is needed;
the bonus is that most parts in the bags arrive partially assembled.
The preassembled parts just need a going through with the
recommended thread-locking compound.
Both main rotor grips and the main rotor housing have a
streamlined design, yet they look strong enough to withstand the
most demanding maneuvers in 3-D flying. A critical step is
installing the thrust bearing the way it is labeled. Even the most
inexperienced builder won’t have a problem putting this kit together.
Align’s feathering shaft sleeve is one of the 700 head’s key
features that protects the dampener from extreme loads. Align made
sure that the spindle is ready for stress by using 6mm stock instead
of 4mm stock.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:50 AM Page 58
December 2009 59
Photos by the author and Michael Ramsey
The fan is efficient at cooling the power
system. The clutch has been updated since
this photo was taken.
O.S. got it right with the unpumped
version of the 91HZ. It’s easy to set the
needles and has gobs of power.
The lower frame plate does a great deal to
enhance the single-stacked carbon-fiber
frame’s rigidity.
Dental floss tied to the cotter pin security
system prevents the pins from being lost.
The kit’s organized parts bags are numbered and called out in the well-done instruction
manual. An aluminum and a carbon-fiber tailboom are included.
A Hatori muffler system is an outstanding complement to any helicopter. Shown is the
Bobby Watts Special, which offers a quiet exhaust note and oodles of power.
JR DS8717 servos were used on
the indirect cyclic controls. The
CCPM mechanics use a 120°
offset system.
Torque-drive transfer gears are robust,
with a key and pin mount system for
security. Plastic tail grips are lightweight.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 59
60 MODEL AVIATION
Test-Model Details
Engine used: O.S. 91HZ; Hatori SB-
20FH tuned muffler
Fuel: Byron Fuels Rotor Rage
Radio system: Spektrum DX7se
transmitter; AR7100R receiver;
Spartan DS760 gyro; JR DS8900G tail
servo; three JR DS8717 cyclic servos;
2400 mAh, 7.4-volt battery; Align
regulator; Align RCE-G600 Governor
Ready-to fly weight: 9.3 pounds
Flight duration: Eight to 10 minutes
Type: RC 90-class nitro-powered
helicopter
Rotor diameter: 61.50-63.07 inches
Tail-rotor diameter: 11.06 inches
Weight (without power system):
112.9 ounces
Length: 52.56 inches
Height: 17.72 inches
Engine: .91 cu. in. and muffler
Engine pinion gear: 20 teeth
Autorotation tail gear: 150 teeth
Gear ratio: 8.2:1:4.54
Construction: Single-stack carbonfiber
main frame
Control system: indirect CCPM
mechanics
Drive system: Two-stage main gear,
torque-tube tail control
Main rotor blades: 690mm-710mm
(not included)
Tailboom: Aluminum or carbon-fiber
tube with aluminum bracing
Canopy: Prepainted fiberglass
Fuel tank capacity: 630cc
Requires: Six- to eight-channel radio,
four servos, gyro, receiver battery
Price: $788.99
Specifications
Pluses and Minuses
+•
Simple, lightweight design provides
awesome flight performance.
• +/-13° collective pitch is possible for
extreme 3-D performance.
• Forward-mounted tail servo helps keep
exhaust oil from entering.
• Torque-tube-driven tail offers incredible
pirouette agility.
• Efficient airflow provides reliable engine
cooling and power. -•
Check the Web site for a new clutch
design. Replacing the original is worth it.
Spins and spirals are demanding tail-rotorauthority
maneuvers that this machine
handles extremely well. The head turns at
close to 2,150 rpm for 3-D.
Align’s 710mm 3-D blades are strong and
can handle the pops and stops of Tic-Toc
maneuvers.
Andy used Byron Rotor Rage fuel
throughout the six months of testing the
700. The engine’s insides still look new!
The vertical fin offers lots of protection against tail strikes. The T-Rex 700 is exceptionally
honest in cyclic control with little mixing noticed.
The one-piece 5mm x 24mm linkage
ball not only provides a stronger
connection, but it also contributes to the TRex
700’s overall build principle of having
a lower parts count. The metal seesaw,
flybar, and mixing arms are free and
smooth.
The swashplate is configured for 120°
cyclic/collective pitch mixing (CCPM)
geometry. Another feature I like is that the
washout base pin guides are against the
main shaft. This keeps the pins from
flexing away from the washout base.
12sig2.QXD_00MSTRPG.QXD 10/23/09 9:51 AM Page 60
The main shaft is 12mm thick and
supports the head assembly with three M4
socket-head screws. One of the head
screws goes through the head block and
main shaft, and the other two lock against
the main shaft to prevent wobbling.
Following the success of the 600-class
clutch assembly, the 700 has a similar
design that features the clutch liner and
clutch gear preinstalled to the clutch bell.
The clutch bearing block securely holds
three bearings plus a fourth bearing in the
clutch bell. This assures smooth operation
of the power-transfer assembly.
With most of us using governors on
our helicopters for a more consistent rpm
during flight, Align has included the RCEG600.
The company has also designed the
clutch bell to hold two magnets for the
sensor, making it not only easy to install
but also simple to accurately locate the
sensor.
Assembling the carbon-fiber frame
begins with installing the metal tail
control arm, which is bolted against the
right-side frame using a frame-mounting
block. How much tail authority is
available to the pilot is obvious once this
block is in place. In addition, the assembly
itself is extremely smooth.
The left frame is where most of the
things pieced together earlier, but several
bolts/screws need to be left approximately
a half-turn loose for later alignment
purposes. The front and rear bottom frame
supports are doubled, because they also
locate the carbon bottom plate and landing
gear.
Notice that the main-shaft bearing
blocks are angled in a way that provides
more spacing between bearing blocks.
This is a carefully considered design
feature that offers a mechanical advantage
to the main shaft. Main machines employ
three bearings to support the main shaft,
but Align found that the two-bearing
design had less drag.
Use the outer opening of the tank to
install the clunk assembly. This way,
when you need to do a maintenance check
for possible leaks, it will be much easier
access than reaching between the frame
or, worse, having to take the tank off.
With the tank finished, you can join the
two carbon side frames.
At this point in the build, it is
recommended that you mount your engine
of choice. Before this, I prepped my O.S.
91HZ by installing the clutch, fan, and fan
shroud assembly.
The fan has a unique design that
increases its ability to take in air and, at
the same time, lower the load needed to
propel the fan itself. That is
complemented with the fan shroud interior
design, which provides a secondary fin to
redirect the air on the head and on the
engine case.
The main shaft is critical to the main
frame’s final alignment. Insert the shaft
through the two bearing blocks. Over a
flat surface, such as a glass table, make
sure the bottom frame is square against
the table. Ensure that the main shaft can
rotate and telescope smoothly before and
while you tighten the bearing blocks
against the frame.
This is also a good time to tighten the
clutch bearing-block screws against the
frame. While doing so, rotate the engine
several times and get a good feel of
freedom of the clutch against the start
shaft. Also do this while tightening the
engine against its mount.
The remainder of the frame assembly
is straightforward and easy. The T-Rex
700’s landing gear is identical to the TRex
600’s, only it’s white. The gear is
strong and provides just enough flex to
take the abuse of a hard landing.
The tailboom mount/block houses the
front gear drive assembly. I recommend
that you apply oil to the bearings, to
ensure smooth operation. I like the way
this piece locks onto the frame and ties
together the front gear drive assembly and
autorotation tail drive gear. The correct
gear mesh is assured.
The tail gearbox is also partially
preassembled. The metal pitch slider is
strong and smooth against the tail output
shaft. The specially designed tail-rotor
hub and the plastic tail grips that are on
the T-Rex 600 are also on the 700.
The tailboom self-aligns and locks
against the front boom block and to the
tail gearbox with the aid of the vertical
stabilizer mount. It includes a pin that
goes through the boom and gearbox.
With the two bearings glued against
the torque tube, rubber bearing holders
serve as dampening material for the
torque-tube assembly. Oil helps the two
rubber bearing holders fit more easily
inside the tailboom.
I recommend that you add a couple of
tail pushrod guides, making a total of five.
The additional pushrod support prevents
flexing, which will increase the gyro’s
effectiveness.
The overall build, including
photography, took only a day. The T-Rex
kit is a joy to assemble, and I believe that
even the most inexperienced helicopter
pilot could successfully build this
machine.
Reliability Test: Part of this review is to
see how the T-Rex 700 handles in flight
and, most important, how it will handle
after months of flying.
I’ve owned and flown several 90-size
helicopters from different manufacturers,
so I was interested in how this helicopter
would perform. Off the bench, it flew
smoothly and tracked straight both
upwind and downwind.
I noticed that the T-Rex 700 tended to
roll during forward flips, so I re-examined
my setup and made sure that the
swashplate stayed level in all collective
stick positions. I tweaked the model here
and there, retrimmed it for “flip-ability,”
and made sure that it tracked straight
during climbout right-side up and upsidedown.
After that bit of effort, the aircraft
flew better in all attitudes.
Its CG appears to be where it needs to
be, as evidenced by the helicopter’s
ability to roll smoothly along its axis. In
addition, the forward and backward flips
are easy to keep in one spot.
During the initial flights, it felt like I
needed to push the T-Rex 700 to fly
faster. But once I became accustomed to
its ability, I realized that it can carry
plenty of speed and perform maneuvers.
This machine can easily make a pilot look
skilled and doesn’t have the feeling of
being oversensitive.
Maintenance: Several screws needed to
be thread-locked again after the first
through fifth flights, which I consider
normal on a new helicopter. Six months
into flying it, I’ve replaced the head
dampener twice and gone through two
clutches. I also crashed the model twice.
Besides being easy to build, the T-Rex
700 is easy to repair and maintain. After
the first crash, I had to replace the
spindle, main shaft, front landing gear,
tailboom, and boom supports. The repair
took slightly more than an hour, which
meant that I could have gone back out to
fly it that afternoon.
There were rumors of ball links failing
during flight, but I still have the original
links on my model—and that’s flying in
the cold conditions here in Indiana. I also
flew the machine in the Philippines in
January and exposed those links to
extremely hot conditions.
Align started releasing parts that are
labeled “-1,” and one of the first was the
main gear. In six months of flying my TRex
700, I’ve replaced one main gear
because it stripped in flight. I’ve switched
back and forth between the older and new
main gear, and both types are holding up
fine.
The only part I’d consider replacing
from the start is the clutch, since I broke
two in flight. You can make this swap at
the field, so consider doing so before the
original part surprises you.
Align’s T-Rex 700 is well made and is
designed to keep the pilot flying. It’s
simple to construct, maintain, and fix, and
the model and parts are reasonably priced,
with hobby shop support almost
everywhere. What else could you want?
Align raised the bar and gave us
something we can likely afford, in
addition to the features I have mentioned.
I enjoyed this project so much that now I
have three T-Rex 700s—all ready to fly.
See you at the field! MA
Andy Panoncillo
[email protected]
Manufacturer/Distributor:
Align/Assurance RC USA
3626 Briggeman Dr.
Los Alamitos CA 90720
(562) 598-4700
www.alignusa.com
Sources:
Spektrum/JR
(800) 338-4639
www.horizonhobby.com
O.S. Engines
(217) 398-8970
www.osengines.com
Hatori USA:
Great Hobbies
(716) 297-3295
www.greathobbies.com
Spartan RC
+44 7092 862003
www.spartan-rc.com
Other Published Reviews:
None known at time of publication