130 MODEL AVIATION
[[email protected]]
Radio Control Jets Jim Hiller
PST Reaction 54 sport jet flight-test report
Above: This flap hinge on the PST Reaction
54 has, as do all flight controls, sealed
surface hinges that are clean. The servo is
mounted in the hatch for easy access.
Right: Smart-Fly’s Eq6 system powers a
Spektrum AR9000 receiver. Dual 3850 mAh
2S Li-Poly batteries provide regulated,
redundant power.
PST Jets updated the BTE Reaction 54 to fiberglass
composite construction. This model is a durable version of
the classic design.
I’M GOING TO share my experiences with
a PST Jets Reaction 54 sport model. Sung
Kim of California owns and flies this
particular jet, and he trusted me with his
beauty so I could familiarize myself with it.
(He didn’t know how I fly.) Bruce Tharpe
Engineering (BTE) designed and sells the
Reaction 54, which is a good platform with
which to transition from propeller-equipped
aircraft to jet-powered models.
The Reaction 54 is built up from balsa, is
extraordinarily light for its size, and has
developed a great reputation as a sport jet
for grass-field operations. It is typically
powered by 14- to 20-pound-thrust turbines
and weighs 20 pounds or lighter. This results
in a wing loading of fewer than 32 ounces
per square foot—perfect for grass fields.
PST Jets liked the Reaction 54 so much
that the company worked with Bruce Tharpe
to develop a composite version. It is painted
in the mold, with all the latest ARF features
found in models with this type of
construction. The fuselage, wing, and tail
surfaces are molded fiberglass, available in
various color schemes, and require little
building.
You might think that the work required
to equip a PST Reaction 54 consists of
assembly-type operations. The only
construction and gluing necessary is during
installation of the systems within the
airframe: radio, turbine, and fuel tank.
The Reaction 54 has a wingspan of 78
inches with a wide chord, resulting in a
wing area of 1,453 square inches, and a
thick, symmetrical airfoil. The model’s
overall length is 77 inches, with room for
turbines ranging from 14 to 36 pounds of
thrust. The empty weight is expected to be
22-27 pounds, based on turbine and
equipment selection. This is a large aircraft.
As I noted, the preferred power plant for
the Reaction 54 is a 14- to 26-pound turbine.
However, Sung powered his model with a
JetCat P160 36-pound-thrust kerosene-start
turbine; this was going to be fun.
The fuel capacity is the standard 2.5-liter
fiberglass tank, supplemented by a 32-ounce
tank; that allows for approximately 100
ounces of fuel. The fuel feed is from the 2.5-
liter tank to the 32-ounce tank, and then to a
BVM (Bob Violett Models) Ultimate Air
Trap. This system has proven to be reliable
in eliminating air bubbles that are fed to the
fuel pump.
The Reaction 54 has some serious
electronics. A Spektrum 9000 receiver sits
on top of a Smart-Fly Eq6 expander board,
with a fan-cooled regulator to reduce the
voltage of two 3850 mAh, two-cell Li-Poly
battery packs. Typical servos used
throughout the flight surfaces are JR 8611s;
there is no lack of servo power in this
installation.
The new Spektrum setup was great for
our test. Sung sent the airframe and kept his
transmitter. I merely had to bind my
transmitter to the Reaction 54’s receiver, set
up the control throws, and everything was
ready to fly.
Enough with the specifications; how did
this jet fly? Sung loaned it to me for three
06sig5.QXD 4/23/09 1:54 PM Page 130
months—of winter flying in northeast Ohio.
We had been having plenty of cold and
snow, so my options were limited; I picked
the best days I could—cold but with
minimum wind chill. The warmest day I
chose was 30°, and the coldest was 15°;
these temperatures make for great power
from the turbine—not that the P160 is a
slouch.
The Reaction 54’s wing boasts more than
10 square feet of area. At 26 pounds (empty
weight), that’s only a 42-ounce wing
loading.
And this was a heavy model, loaded with
a big turbine and loads of electronics. The
power-to-weight ratio exceeded 1:1 with the
P160, so we were going to go places.
I typically take off with this jet sans flaps;
it already has loads of lift and a great deal of
power. Once off the ground, things happen
fast if you don’t immediately throttle back.
I have found that the Reaction 54 cruises
along well at 80-150 mph. Aerobatics within
that range are comfortable. At the lower
speeds, I use throttle control to maintain a
constant airspeed throughout looping
maneuvers, which is cool on large loops. Yet
at low speed, tight loops of roughly 100 feet
in diameter are also a cinch to execute.
At higher speeds, the size of maneuvers
increases, as it does with any model. If you
want, you can open the throttle the rest of the
way and cruise along at nearly 200 mph,
running along with any high-speed jet.
The amazing thing is that I use the same
control throw rates throughout the entire
speed range. I have the Reaction 54 dialed
in, so I use low-rate ailerons and elevator for
takeoff, landing, and all flight speeds.
There’s no need to flip the rate switches, and
it stays smooth and precise throughout the
speed range.
For my style of flying, the elevator has 1/2
inch up and 5/8 inch down travel, which is
necessary to get equal-size loops upright and
inverted, and 20% exponential (expo). The
elevator expo helps considerably in highspeed
flight.
Aileron travel is 1/2 inch up and down
with 6% expo, and rudder travel is all I can
get with 50% expo. The rudder expo is in
place to soften the nose-gear steering
response on the takeoff roll. Flap travel is
slightly more than 45°.
With its thick symmetrical airfoil, the
Reaction 54 excels at looping maneuvers.
Inside loops and outside loops are identical;
push or pull, the aircraft handles the same.
That’s great for us old RC Aerobatics fliers.
Knife-edge, slow-roll, and point-roll
maneuvers are a weak point for this jet. It
has so much fin area that it is difficult to get
enough rudder travel to kick out the tail
enough to get solid knife-edge lift.
There is adequate power in the rudder at
speeds exceeding 150 mph to do a good job
at holding knife-edge flight. But when
you’re looping and rolling this model at slow
speeds of less than 100 mph, you have to
keep in mind that slow rolls and point rolls
are not going to hold altitude in knife edge.
This would not be an issue for a normal
jet, but it’s so much fun to box in a slow,
tight aerobatic routine with this one that I’m
critical of its slow-speed aerobatic
performance. It’s kind of silly of me; aren’t
jets supposed to be flown at high speeds?
Enough about aerobatics; the Reaction 54
is a transition to jets, so slow-speed handling
for the landing approach and touchdown are
crucial. In that regime of flight, I rate this
model an A+.
Slow-speed flight when pulling a lot of
up-elevator is stable, and the stall itself is
almost a nonissue. A thick airfoil and lowaspect-
ratio, conventional wing really proves
to be a great formula for slow flight. It is fun
to hang on the elevator and fly figure eights
with confidence.
With flaps up, gear up, and speed board
retracted, the Reaction 54 has a fantastic
glide ratio. If you have a flameout, don’t
extend any of them until the jet is over the
runway. With gear down, flaps down, and
the speed board extended, the Reaction 54
surprised me; it has a good approach descent
rate.
To land, I extend the gear downwind and
follow with flaps and speed board as I turn
on base. The elevator trim is set up with the
recommended 1/8-inch down-elevator trim
with flaps—a good mix, which gives a nice
glide speed and good rate of descent. Turn
final, and you can start the flare as high as 6
feet off the ground and still have enough
float to complete a nice touchdown.
If you need a steeper approach, say
coming over a tree line, hang on the elevator
in the base leg, slowing the model. And you
can be comfortable in the knowledge that
your stalling it will be a nonevent—if that
happens.
At this slower speed, the approach
descent is steeper and the final flare must be
executed at a lower level—say, 2 feet off the
ground, as little float is left. That’s great for
precision spot landings in tight fields.
I have had a fun couple of months with the
Reaction 54, and I like it for sport-flying. Its
handling traits are honest; slow-speed flight
is so sweet that it will serve as a good
transition trainer for the new jet modeler and
continue to serve that pilot for many years.
Top speed is good. This is not the fastest
jet at the field, but it’s more than adequate. I
like the composite construction. It is tough,
hangar rash resistance is great, and I have
experienced no issues with the airframe; I
just flew it. Maintenance consisted only of
refueling, charging, and greasing the wheel
axles.
Sung, thanks for the use of your jet. I hate
to give it up. PST and Bruce Tharpe, great
job on the Reaction 54; it fulfills the promise
of being a good-flying sport jet.
It’s on to Florida Jets, for some warm
weather, good friends, and burning lots of
kerosene, after which I have to return the
Reaction 54. I sure will miss it. MA
Sources:
BTE
(800) 557-4470
www.btemodels.com
JetCat USA
(805) 226-8700
www.jetcatusa.com
BVM
(407) 327-6333
www.bvmjets.com
PST Jets (Bangkok, Thailand)
+662 318-6918
www.pstjets.com
Smart-Fly
(480) 460-2652
www.smart-fly.com
Edition: Model Aviation - 2009/06
Page Numbers: 130,131
Edition: Model Aviation - 2009/06
Page Numbers: 130,131
130 MODEL AVIATION
[[email protected]]
Radio Control Jets Jim Hiller
PST Reaction 54 sport jet flight-test report
Above: This flap hinge on the PST Reaction
54 has, as do all flight controls, sealed
surface hinges that are clean. The servo is
mounted in the hatch for easy access.
Right: Smart-Fly’s Eq6 system powers a
Spektrum AR9000 receiver. Dual 3850 mAh
2S Li-Poly batteries provide regulated,
redundant power.
PST Jets updated the BTE Reaction 54 to fiberglass
composite construction. This model is a durable version of
the classic design.
I’M GOING TO share my experiences with
a PST Jets Reaction 54 sport model. Sung
Kim of California owns and flies this
particular jet, and he trusted me with his
beauty so I could familiarize myself with it.
(He didn’t know how I fly.) Bruce Tharpe
Engineering (BTE) designed and sells the
Reaction 54, which is a good platform with
which to transition from propeller-equipped
aircraft to jet-powered models.
The Reaction 54 is built up from balsa, is
extraordinarily light for its size, and has
developed a great reputation as a sport jet
for grass-field operations. It is typically
powered by 14- to 20-pound-thrust turbines
and weighs 20 pounds or lighter. This results
in a wing loading of fewer than 32 ounces
per square foot—perfect for grass fields.
PST Jets liked the Reaction 54 so much
that the company worked with Bruce Tharpe
to develop a composite version. It is painted
in the mold, with all the latest ARF features
found in models with this type of
construction. The fuselage, wing, and tail
surfaces are molded fiberglass, available in
various color schemes, and require little
building.
You might think that the work required
to equip a PST Reaction 54 consists of
assembly-type operations. The only
construction and gluing necessary is during
installation of the systems within the
airframe: radio, turbine, and fuel tank.
The Reaction 54 has a wingspan of 78
inches with a wide chord, resulting in a
wing area of 1,453 square inches, and a
thick, symmetrical airfoil. The model’s
overall length is 77 inches, with room for
turbines ranging from 14 to 36 pounds of
thrust. The empty weight is expected to be
22-27 pounds, based on turbine and
equipment selection. This is a large aircraft.
As I noted, the preferred power plant for
the Reaction 54 is a 14- to 26-pound turbine.
However, Sung powered his model with a
JetCat P160 36-pound-thrust kerosene-start
turbine; this was going to be fun.
The fuel capacity is the standard 2.5-liter
fiberglass tank, supplemented by a 32-ounce
tank; that allows for approximately 100
ounces of fuel. The fuel feed is from the 2.5-
liter tank to the 32-ounce tank, and then to a
BVM (Bob Violett Models) Ultimate Air
Trap. This system has proven to be reliable
in eliminating air bubbles that are fed to the
fuel pump.
The Reaction 54 has some serious
electronics. A Spektrum 9000 receiver sits
on top of a Smart-Fly Eq6 expander board,
with a fan-cooled regulator to reduce the
voltage of two 3850 mAh, two-cell Li-Poly
battery packs. Typical servos used
throughout the flight surfaces are JR 8611s;
there is no lack of servo power in this
installation.
The new Spektrum setup was great for
our test. Sung sent the airframe and kept his
transmitter. I merely had to bind my
transmitter to the Reaction 54’s receiver, set
up the control throws, and everything was
ready to fly.
Enough with the specifications; how did
this jet fly? Sung loaned it to me for three
06sig5.QXD 4/23/09 1:54 PM Page 130
months—of winter flying in northeast Ohio.
We had been having plenty of cold and
snow, so my options were limited; I picked
the best days I could—cold but with
minimum wind chill. The warmest day I
chose was 30°, and the coldest was 15°;
these temperatures make for great power
from the turbine—not that the P160 is a
slouch.
The Reaction 54’s wing boasts more than
10 square feet of area. At 26 pounds (empty
weight), that’s only a 42-ounce wing
loading.
And this was a heavy model, loaded with
a big turbine and loads of electronics. The
power-to-weight ratio exceeded 1:1 with the
P160, so we were going to go places.
I typically take off with this jet sans flaps;
it already has loads of lift and a great deal of
power. Once off the ground, things happen
fast if you don’t immediately throttle back.
I have found that the Reaction 54 cruises
along well at 80-150 mph. Aerobatics within
that range are comfortable. At the lower
speeds, I use throttle control to maintain a
constant airspeed throughout looping
maneuvers, which is cool on large loops. Yet
at low speed, tight loops of roughly 100 feet
in diameter are also a cinch to execute.
At higher speeds, the size of maneuvers
increases, as it does with any model. If you
want, you can open the throttle the rest of the
way and cruise along at nearly 200 mph,
running along with any high-speed jet.
The amazing thing is that I use the same
control throw rates throughout the entire
speed range. I have the Reaction 54 dialed
in, so I use low-rate ailerons and elevator for
takeoff, landing, and all flight speeds.
There’s no need to flip the rate switches, and
it stays smooth and precise throughout the
speed range.
For my style of flying, the elevator has 1/2
inch up and 5/8 inch down travel, which is
necessary to get equal-size loops upright and
inverted, and 20% exponential (expo). The
elevator expo helps considerably in highspeed
flight.
Aileron travel is 1/2 inch up and down
with 6% expo, and rudder travel is all I can
get with 50% expo. The rudder expo is in
place to soften the nose-gear steering
response on the takeoff roll. Flap travel is
slightly more than 45°.
With its thick symmetrical airfoil, the
Reaction 54 excels at looping maneuvers.
Inside loops and outside loops are identical;
push or pull, the aircraft handles the same.
That’s great for us old RC Aerobatics fliers.
Knife-edge, slow-roll, and point-roll
maneuvers are a weak point for this jet. It
has so much fin area that it is difficult to get
enough rudder travel to kick out the tail
enough to get solid knife-edge lift.
There is adequate power in the rudder at
speeds exceeding 150 mph to do a good job
at holding knife-edge flight. But when
you’re looping and rolling this model at slow
speeds of less than 100 mph, you have to
keep in mind that slow rolls and point rolls
are not going to hold altitude in knife edge.
This would not be an issue for a normal
jet, but it’s so much fun to box in a slow,
tight aerobatic routine with this one that I’m
critical of its slow-speed aerobatic
performance. It’s kind of silly of me; aren’t
jets supposed to be flown at high speeds?
Enough about aerobatics; the Reaction 54
is a transition to jets, so slow-speed handling
for the landing approach and touchdown are
crucial. In that regime of flight, I rate this
model an A+.
Slow-speed flight when pulling a lot of
up-elevator is stable, and the stall itself is
almost a nonissue. A thick airfoil and lowaspect-
ratio, conventional wing really proves
to be a great formula for slow flight. It is fun
to hang on the elevator and fly figure eights
with confidence.
With flaps up, gear up, and speed board
retracted, the Reaction 54 has a fantastic
glide ratio. If you have a flameout, don’t
extend any of them until the jet is over the
runway. With gear down, flaps down, and
the speed board extended, the Reaction 54
surprised me; it has a good approach descent
rate.
To land, I extend the gear downwind and
follow with flaps and speed board as I turn
on base. The elevator trim is set up with the
recommended 1/8-inch down-elevator trim
with flaps—a good mix, which gives a nice
glide speed and good rate of descent. Turn
final, and you can start the flare as high as 6
feet off the ground and still have enough
float to complete a nice touchdown.
If you need a steeper approach, say
coming over a tree line, hang on the elevator
in the base leg, slowing the model. And you
can be comfortable in the knowledge that
your stalling it will be a nonevent—if that
happens.
At this slower speed, the approach
descent is steeper and the final flare must be
executed at a lower level—say, 2 feet off the
ground, as little float is left. That’s great for
precision spot landings in tight fields.
I have had a fun couple of months with the
Reaction 54, and I like it for sport-flying. Its
handling traits are honest; slow-speed flight
is so sweet that it will serve as a good
transition trainer for the new jet modeler and
continue to serve that pilot for many years.
Top speed is good. This is not the fastest
jet at the field, but it’s more than adequate. I
like the composite construction. It is tough,
hangar rash resistance is great, and I have
experienced no issues with the airframe; I
just flew it. Maintenance consisted only of
refueling, charging, and greasing the wheel
axles.
Sung, thanks for the use of your jet. I hate
to give it up. PST and Bruce Tharpe, great
job on the Reaction 54; it fulfills the promise
of being a good-flying sport jet.
It’s on to Florida Jets, for some warm
weather, good friends, and burning lots of
kerosene, after which I have to return the
Reaction 54. I sure will miss it. MA
Sources:
BTE
(800) 557-4470
www.btemodels.com
JetCat USA
(805) 226-8700
www.jetcatusa.com
BVM
(407) 327-6333
www.bvmjets.com
PST Jets (Bangkok, Thailand)
+662 318-6918
www.pstjets.com
Smart-Fly
(480) 460-2652
www.smart-fly.com