118 MODEL AVIATION
[[email protected]]
Radio Control Jets Jim Hiller
Build-a-turbine-engine open house
There was no hiding the
goods at the Wren USA
Open Day. This complete
160 turbine was ready for
Ron Ballard to assemble.
Mike Murphy (L) and Ron Ballard (center) at the test stand,
running the kerostart Wren 160, which is still in development.
Scott Reed assembles a Wren 70 from a kit. It was running on the
test stand in roughly three hours. This was one of the great
experiences at the event.
I RECENTLY RETURNED from the
first Wren USA Open Day in Indiana. Ron
Ballard became part of the company a few
years ago and set up shop to service its
turbines in the US. He has built a great
reputation for service and wanted to show
off his shop to friends and customers, so
he invited them in November. What a great
way to end a great flying season.
The schedule for the open house was a
barbecue on Friday night and building,
running, repairing, and discussing turbines
on Saturday. I arrived Friday at roughly
noon and was greeted not only by Ron
Ballard, but also by Mike Murphy of Wren
Turbines.
Mike had flown in from England to
attend this event. He is one of the
company’s original developers and
owners, and he knows his turbines.
Ron and Mike were in the middle of
running and refining turbines when I
arrived—something they had been doing
most of the week, because Mike had
arrived early. Wren USA now has a
balancer set up in the shop, with which
Ron has increased the service operations
he can perform and doesn’t have to ship
turbines to Wren in England for repairs.
One of the reasons why Mike had
arrived early was to balance turbine
rotating assemblies with Ron, to exchange
experiences in building and repairing Wren
turbines. The balancers for our small
turbines are accurate and sophisticated
machines that are capable of balancing
shafts, compressors, and turbines, both as
individual items and as assemblies.
The Wren process for balancing is
impressive, and Ron and Mike explained it
all. There were no secrets!
Friday afternoon, those who attended
the Open Day assembled a new Wren 70
from a kit. Scott Reed and Joe Lewis
teamed up to put it together in
approximately three hours, and then they
test-ran it on one of the shop test stands.
The project was successful from the
beginning. The engine started
immediately, ran smoothly and steadily,
and even exceeded the advertised rated
thrust. This is further proof that the Wren
kit concept is a fantastic part of the
product experience.
I noticed one important thing. Except to
give advice about bearing cleanliness,
neither Ron nor Mike stepped in to touch
or advise on the build process. Scott and
Joe simply followed the book and went to
town.
I mention the bearing issue, because
Ron did preach the importance of clean
bearings and how to detect a dirty or
damaged bearing. For the rear bearing, he
held the shaft and turbine assembly,
without the compressor wheel, vertical by
the bearing and spun the shaft.
Ron had us do that with the assembly
straight from the kit. Then he washed the
bearing under hot water from the faucet,
and we repeated the spin test. What a
difference! You could definitely feel the
disparity—much smoother. It was a great
tip. Another is to then apply oil to the
bearing before assembly.
Friday evening, we enjoyed Ron’s
barbecued pork tenderloins; they were to
02sig4.QXD_00MSTRPG.QXD 12/21/09 9:45 AM Page 118
die for. He is a perfectionist not only with
his turbines, but also with his barbecue.
Guests ate until they could eat no more. In
addition, Dave Brawley, alias “Goose,”
had ribs that he barbecued.
Those who arrived on Friday were
spoiled with plenty of great food. Way too
much was grilled, but the plan was to save
some meat for Saturday’s lunch. We ate
well both days.
A Wren 70 was assembled from a kit
on Saturday and, as did the one from
Friday, it started right away. It was also
smooth and exceeded the rated thrust for
that engine.
More than 20 people showed up to
enjoy the Open Day, and some traveled
from long distances; Delaware and
California were represented. Those present
were surprised by the interest that Wren
turbines create.
Demonstration runs of the company’s
kerosene start on a development Wren 160
was practiced on the 34-pound-thrust
turbine. This was definitely the
development setup; it looked like a
porcupine with multiple glow plug
locations, all to find the best spot.
The Wren “kerostart” setup is a glow
plug-and-injector setup, and the plug is
separate from the injector for easy,
economical replacement if required. Many
combinations of batteries, injector/plug
locations, and start procedures were tested
Friday and Saturday.
Ron and Mike did not hide the
development process. They wanted
customer input about how to set up
equipment, and they were willing to try
different combinations all day.
Another neat thing was that while Ron
built a Wren 160, Mike held a class about
turbines. Ron has been an active part of
the Wren 160’s development, and his
knowledge of this power system is
impressive. He openly shared many
nuances of the build process and design of
that engine, even though it is not available
as a kit.
Mike went on to discuss the design and
development of Wren turbines. I believe
that everyone at the open house was
impressed and surprised by his knowledge
and openness about his experiences
developing these engines and by some
facts he shared about turbine engineering.
We learned a great deal about our engines
during this time.
One thing Mike repeatedly stressed in
conversation was that he views open
houses as an avenue by which to learn
what customers like, want, and need in
turbines. He listens to us to guide Wren’s
next move.
There was some discussion about the
Wren 44 Turboprop, which is based on the
company’s 44 turbine. The Turboprop is
an incredible little package. In stock form
it runs a three-blade 22 x 10 propeller, but
that’s with a 9:1 gearbox. The company is
experimenting with a 12:1 gearbox. Initial
runs prove that a two-blade 32 x 10
propeller produces as much as 50 pounds
of thrust.
Besides having the Turboprop to show
us, Ron and Mike also had a gearbox. The
importance of this is that it can be
replaced easily if it is damaged by a
propeller strike. The amount of work
required to repair a bent propeller shaft is
an issue with turboprops.
Wren’s solution is a replaceable
assembly that is quick and
straightforward. You will be flying again
in a minimum amount of time, and the
gearbox can be properly repaired back at
the shop.
Another interesting item Ron and Mike
shared is that Wren Turbines is looking
into not being limited to one electronic
control unit (ECU): the famous FADEC it
has used almost from the beginning. One
of the first runs with a ProJet ECU was
made during Open Day.
The initial parameters were
downloaded into the ECU, and the
development Wren 160 “kerostart” was
run off of the ProJet. After some initial
parameter reviews, the turbine started
immediately and the ProJet was used on it
the rest of the weekend.
ProJet electronics is going in a new
direction and offers interesting options.
Some programming features that are
available in this ECU will allow much
faster acceleration and deceleration times
from partial throttle settings to full
throttle. It’s an extremely well-thoughtout
unit.
The ProJet includes options for
additional data recording and a 2.4 GHz
onboard transmitter, for downloading inflight
turbine information for the pilot. A
display board can be mounted to the
transmitter for data, or a speech module
can be added that allows the pilot to listen
for information such as fuel consumption.
It would be neat to have active
knowledge of how much fuel is
remaining. I could stretch flight times
with that real-time data. Oh yeah, the
wheels are turning.
Also at Open Day, a table full of boxed
turbines that attendees had shipped to the
company for repairs awaited us. Many of
them were fixed by their owners, under
the tutelage of the Wren masters.
Upon completion of repairs, or in some
cases upgrades to the most current
revisions, the engines were run on a test
stand. It was equipped with thrust
measurement, so an underperforming unit
could be detected; all turbines must make
thrust ratings. It’s nice to see this
openness.
The event ended late Saturday afternoon,
with farewells and Ron’s promise to do it
again. Those who attended learned a great
deal—more than I could detail in this little
column. There were also promises of
exciting new things coming from Wren
Turbines. MA
Sources:
Wren USA
(260) 724-8936
http://wrenturbines.co.uk/usa
Jet Pilots Association
(904) 318-7171
www.jetpilots.org
Edition: Model Aviation - 2010/02
Page Numbers: 118,120
Edition: Model Aviation - 2010/02
Page Numbers: 118,120
118 MODEL AVIATION
[[email protected]]
Radio Control Jets Jim Hiller
Build-a-turbine-engine open house
There was no hiding the
goods at the Wren USA
Open Day. This complete
160 turbine was ready for
Ron Ballard to assemble.
Mike Murphy (L) and Ron Ballard (center) at the test stand,
running the kerostart Wren 160, which is still in development.
Scott Reed assembles a Wren 70 from a kit. It was running on the
test stand in roughly three hours. This was one of the great
experiences at the event.
I RECENTLY RETURNED from the
first Wren USA Open Day in Indiana. Ron
Ballard became part of the company a few
years ago and set up shop to service its
turbines in the US. He has built a great
reputation for service and wanted to show
off his shop to friends and customers, so
he invited them in November. What a great
way to end a great flying season.
The schedule for the open house was a
barbecue on Friday night and building,
running, repairing, and discussing turbines
on Saturday. I arrived Friday at roughly
noon and was greeted not only by Ron
Ballard, but also by Mike Murphy of Wren
Turbines.
Mike had flown in from England to
attend this event. He is one of the
company’s original developers and
owners, and he knows his turbines.
Ron and Mike were in the middle of
running and refining turbines when I
arrived—something they had been doing
most of the week, because Mike had
arrived early. Wren USA now has a
balancer set up in the shop, with which
Ron has increased the service operations
he can perform and doesn’t have to ship
turbines to Wren in England for repairs.
One of the reasons why Mike had
arrived early was to balance turbine
rotating assemblies with Ron, to exchange
experiences in building and repairing Wren
turbines. The balancers for our small
turbines are accurate and sophisticated
machines that are capable of balancing
shafts, compressors, and turbines, both as
individual items and as assemblies.
The Wren process for balancing is
impressive, and Ron and Mike explained it
all. There were no secrets!
Friday afternoon, those who attended
the Open Day assembled a new Wren 70
from a kit. Scott Reed and Joe Lewis
teamed up to put it together in
approximately three hours, and then they
test-ran it on one of the shop test stands.
The project was successful from the
beginning. The engine started
immediately, ran smoothly and steadily,
and even exceeded the advertised rated
thrust. This is further proof that the Wren
kit concept is a fantastic part of the
product experience.
I noticed one important thing. Except to
give advice about bearing cleanliness,
neither Ron nor Mike stepped in to touch
or advise on the build process. Scott and
Joe simply followed the book and went to
town.
I mention the bearing issue, because
Ron did preach the importance of clean
bearings and how to detect a dirty or
damaged bearing. For the rear bearing, he
held the shaft and turbine assembly,
without the compressor wheel, vertical by
the bearing and spun the shaft.
Ron had us do that with the assembly
straight from the kit. Then he washed the
bearing under hot water from the faucet,
and we repeated the spin test. What a
difference! You could definitely feel the
disparity—much smoother. It was a great
tip. Another is to then apply oil to the
bearing before assembly.
Friday evening, we enjoyed Ron’s
barbecued pork tenderloins; they were to
02sig4.QXD_00MSTRPG.QXD 12/21/09 9:45 AM Page 118
die for. He is a perfectionist not only with
his turbines, but also with his barbecue.
Guests ate until they could eat no more. In
addition, Dave Brawley, alias “Goose,”
had ribs that he barbecued.
Those who arrived on Friday were
spoiled with plenty of great food. Way too
much was grilled, but the plan was to save
some meat for Saturday’s lunch. We ate
well both days.
A Wren 70 was assembled from a kit
on Saturday and, as did the one from
Friday, it started right away. It was also
smooth and exceeded the rated thrust for
that engine.
More than 20 people showed up to
enjoy the Open Day, and some traveled
from long distances; Delaware and
California were represented. Those present
were surprised by the interest that Wren
turbines create.
Demonstration runs of the company’s
kerosene start on a development Wren 160
was practiced on the 34-pound-thrust
turbine. This was definitely the
development setup; it looked like a
porcupine with multiple glow plug
locations, all to find the best spot.
The Wren “kerostart” setup is a glow
plug-and-injector setup, and the plug is
separate from the injector for easy,
economical replacement if required. Many
combinations of batteries, injector/plug
locations, and start procedures were tested
Friday and Saturday.
Ron and Mike did not hide the
development process. They wanted
customer input about how to set up
equipment, and they were willing to try
different combinations all day.
Another neat thing was that while Ron
built a Wren 160, Mike held a class about
turbines. Ron has been an active part of
the Wren 160’s development, and his
knowledge of this power system is
impressive. He openly shared many
nuances of the build process and design of
that engine, even though it is not available
as a kit.
Mike went on to discuss the design and
development of Wren turbines. I believe
that everyone at the open house was
impressed and surprised by his knowledge
and openness about his experiences
developing these engines and by some
facts he shared about turbine engineering.
We learned a great deal about our engines
during this time.
One thing Mike repeatedly stressed in
conversation was that he views open
houses as an avenue by which to learn
what customers like, want, and need in
turbines. He listens to us to guide Wren’s
next move.
There was some discussion about the
Wren 44 Turboprop, which is based on the
company’s 44 turbine. The Turboprop is
an incredible little package. In stock form
it runs a three-blade 22 x 10 propeller, but
that’s with a 9:1 gearbox. The company is
experimenting with a 12:1 gearbox. Initial
runs prove that a two-blade 32 x 10
propeller produces as much as 50 pounds
of thrust.
Besides having the Turboprop to show
us, Ron and Mike also had a gearbox. The
importance of this is that it can be
replaced easily if it is damaged by a
propeller strike. The amount of work
required to repair a bent propeller shaft is
an issue with turboprops.
Wren’s solution is a replaceable
assembly that is quick and
straightforward. You will be flying again
in a minimum amount of time, and the
gearbox can be properly repaired back at
the shop.
Another interesting item Ron and Mike
shared is that Wren Turbines is looking
into not being limited to one electronic
control unit (ECU): the famous FADEC it
has used almost from the beginning. One
of the first runs with a ProJet ECU was
made during Open Day.
The initial parameters were
downloaded into the ECU, and the
development Wren 160 “kerostart” was
run off of the ProJet. After some initial
parameter reviews, the turbine started
immediately and the ProJet was used on it
the rest of the weekend.
ProJet electronics is going in a new
direction and offers interesting options.
Some programming features that are
available in this ECU will allow much
faster acceleration and deceleration times
from partial throttle settings to full
throttle. It’s an extremely well-thoughtout
unit.
The ProJet includes options for
additional data recording and a 2.4 GHz
onboard transmitter, for downloading inflight
turbine information for the pilot. A
display board can be mounted to the
transmitter for data, or a speech module
can be added that allows the pilot to listen
for information such as fuel consumption.
It would be neat to have active
knowledge of how much fuel is
remaining. I could stretch flight times
with that real-time data. Oh yeah, the
wheels are turning.
Also at Open Day, a table full of boxed
turbines that attendees had shipped to the
company for repairs awaited us. Many of
them were fixed by their owners, under
the tutelage of the Wren masters.
Upon completion of repairs, or in some
cases upgrades to the most current
revisions, the engines were run on a test
stand. It was equipped with thrust
measurement, so an underperforming unit
could be detected; all turbines must make
thrust ratings. It’s nice to see this
openness.
The event ended late Saturday afternoon,
with farewells and Ron’s promise to do it
again. Those who attended learned a great
deal—more than I could detail in this little
column. There were also promises of
exciting new things coming from Wren
Turbines. MA
Sources:
Wren USA
(260) 724-8936
http://wrenturbines.co.uk/usa
Jet Pilots Association
(904) 318-7171
www.jetpilots.org