150 MODEL AVIATION
Genesis Extreme Electric Retrofit Project report
[[email protected]]
Control Line Aerobatics Bob Hunt
Also included in this column:
• Don’t give up on a model
too quickly
Bob sent a set of Genesis Extreme pencil drawings to his friend, Peter White, in
Australia, and this is the outstanding result. Peter installed a Stalker glow engine in his
version of the model.
Bob debuted his converted Genesis Extreme at
the 2005 FAI Team Trials. He was the first US
pilot to qualify for an FAI team flying an electric
model. At this point the battery was loaded
from the bottom and the AXI 2826/10 was rear
mounted.
The updated Genesis accepts a top-loaded battery and the AXI
2826/10 is now front mounted. The paint trim scheme had to be
modified after the changeover. Bob picked up on the red, white,
and blue trim on the flaps. Way to nail the project, Bob!
BEFORE WE GET back to the essential shop items required for
building a world-beater CL Precision Aerobatics (Stunt) model, I’ll
give you an update on the Genesis Extreme Electric Retrofit
Project.
If you recall, I was retrofitting a front-mounted AXI 2826/10
motor into the model where a rear-mounted AXi had previously
resided. The reason for the changeover was that the rear-mounted
power plant was not lasting more than approximately 70-90 flights
before experiencing bearing failure.
That failure was probably caused by the fact that the motor
weight and induced propeller loads—all forward of the mount—
were producing a cantilever effect and “coning” out the rear
bearing mount; at least that’s the conclusion at which we (Dean
Pappas and I) arrived.
The thought was to front mount the AXi and then install a rear
bearing mount that would support both ends of the motor shaft and
prevent the motor from “flexing.” All that worked fine, but it cost a
bit of weight, added considerable complexity, and made it more
difficult to direct cooling air around the motor and out of the
model.
It was decided to run the AXi without the rear bearing. From
that we learned that by front-mounting the motor we eliminated a
good deal of the cantilever effect.
We ended up running the power plant without the rear bearing
support and now think that the front mounting was all that was
necessary. When the motor was rear mounted, we heard a
pronounced change in the sound of it when each abrupt change of
direction was made, as in the corners of a square. By merely frontmounting
the motor, virtually all of that noise went away.
We reached the conclusion that locating the propeller and spinner
on one side of the mount and the rotating motor can on the other
balanced out the cantilever effect. The jury is still out until we see how
many flights we will get with the front-mounted motor with an
unsupported shaft at the rear. But I’m fairly confident that the problem
is essentially solved.
My very good friend and flying friend, Buddy Wieder, put the rear
bearing mount I have described in his Ryan’s Eagle and flew it several
times with the arrangement in place. The model needed to shed a few
grams in the nose to make it turn a bit better, so Buddy removed the
rear bearing and the attendant plywood yoke in which the bearing
resided.
He has flown the model at least 100 times since then, and the results
so far are good. There has been no bearing failure.
So the Genesis Extreme now has a new motor mount, and it has a
removable top hatch to allow me to top-load the battery. That has made
changing the battery much easier than when I had to invert the model
after every flight and “fold” the electronics back to remove it. It has
also allowed me to mount the battery higher in the airplane.
11sig5.QXD_00MSTRPG.QXD 9/23/10 10:24 AM Page 150
A side benefit is that all of the
“electronics” now reside in the bottom
block, which makes the entire installation
look much more sanitary.
I wanted to be able to mount the battery
higher in the aircraft, because I felt that
there was a vertical CG issue and thought
that mounting the battery higher might fix
it. This particular Genesis has always been
more than a bit roll-trim sensitive, and I
have tried many combinations of flap
tweaks and tip weight in an effort to get the
model to behave properly.
It has always wanted to lift the outside
wing during maneuvers. Whenever I put in
more tip weight to counter this tendency, it
has resulted in a tip “bang” at the corners.
That was frustrating to say the least. With
the battery mounted higher in the model, I
felt that a good deal of the roll problem—
but not all of it—had been eliminated.
The Genesis had also picked up a
tendency to “hunt” in level flight and not
“lock” after a maneuver. I finally started
sighting and measuring to see what the
problem was.
The wing was perfect and had no warps;
of that I was sure. Then I checked the
elevators and found a pronounced upward
curl in the inboard elevator. The curl started
at close to the half-span point and ran up a
good 1/8 inch to the tip! How could I have
missed that?
I bent the inboard elevator down in
relation to the outboard elevator in an effort
to average out the effect of the curl. That
curl was in the direction that would tend to
roll the model to the left and hence lift the
outboard wing, which was the problem I
had long been trying to fix.
With the inboard elevator tweaked down
nearly 3/32 inch, the roll stopped and the
model locked securely upon returning to
level flight after maneuvers. Problem
solved.
With the extreme nose modifications
required to change the model from a bottom
loader to a top loader, it was necessary to
repaint the nose. Matching the original
paint would have been impossible because
of fading from exposure to the sun
throughout the years.
I studied the model and decided to put
red, white, and blue slashes on the nose,
which would complement the red, white,
and blue bars that I had put on the flaps
when I originally painted the Genesis. I had
always liked those bars on Les McDonald’s
Stilettos, and I stole them. I’m glad I did,
because the new nose trim doesn’t look out
of place—too much.
I built the model in 2001, and it has
given me a lot of service but has never been
perfect. I’ve worked on it in many ways to
improve its performance throughout the
years, and that included four different
power trains: two glow and two electric. I
felt that one more major modification was
warranted: to remove the stock elevators
and retrofit new, more accurate ones.
To do this, I cut around the stock hinges
where they were glued into the elevators
and then cut a groove to allow me to
remove them from the horn wire in one
piece. I could then use each elevator as a
template with which to trace a new one on
fresh balsa.
I left the Great Planes Medium Pinned
Hinges in place in the stabilizer and simply
held each new elevator under the hinges to
mark out the position of the hinge pockets.
I finished the new elevators off of the
airplane and then attached them
permanently using RC/56 canopy glue to
secure the hinges into the slots. This
adhesive sticks well to plastics but does not
shrink and cause surface blemishes, as
yellow wood glue does.
The result is a model that finally flies to
my liking. It still looks good and should
have a long life ahead of it—especially now
that it has no-vibration electric power.
I’m going to make one more
modification to this aircraft. With the stocklength
landing gear, it’s unable to swing the
new APC 13 x 4.5P. That propeller has
proven to be an excellent match to the AXi
motor in many other models.
I’m currently running an APC 12 x
6EP. It works fine, but I’m certain that the
13-inch will improve the performance yet
another notch. This will require new
wheel pants to be made, but that’s okay;
the existing ones are getting beaten up
anyway.
wanted to go through all the trials and
tribulations I experienced with the
Genesis Extreme to make a point: that you
should not give up on a model too
quickly. Many that are hard to trim or that
don’t fly as well as you expect might need
a bit of thought and a few small
modifications to make them perform
excellently.
I’ve been asked many times for plans
for this airplane. I’ve run off a few sets of
the pencil drawings from which it was
built but have hesitated to draw it
formally because of the trim problems that
the original displayed.
Now that those problems are fixed and
I know that the design is good, I’ll start on
a set of proper plans. They will feature
both “Glow Nose” and “Electric Nose”
construction details.
I sent one set of pencil drawings to
Peter White in Australia, and he produced
a nice rendition of the model. I’ll end this
month’s columns with a few comments
from Peter. I’ll be back next time with
more shop stuff.
“The Genesis Extreme electric
conversion must have been quite a
project. I envy anyone who can do a job
such as that with no evidence of
‘collateral damage’ … and the outcome
looks great.
“There is a group of guys in New
South Wales who are beginning to work
on electrics. I wouldn’t be surprised to
see two or three at the next Nats. You
obviously haven’t found any real
downsides compared to IC power.
“I have included some shots of a
familiar looking model that I built last
year for the Nats but didn’t get the
opportunity to trim it out and familiarize
myself with it due to constant wind. The
only field I can fly on (legally) during the
week is surrounded by trees which cause
some horrendous turbulence. Flight
trimming there is pointless and rather
dangerous.
“The model, weighing a touch over 56
ounces, is fitted with a Stalker 61LS and
feels quite good in its present state. If the
wind ever slows down enough, and it has
blown quite strongly for the last six
weeks, I’ll get back into more trimming
and see how it turns out.” MA
Sources:
Precision Aerobatics Model Pilots
Association
www.control-line.org
Edition: Model Aviation - 2010/11
Page Numbers: 150,151,152
Edition: Model Aviation - 2010/11
Page Numbers: 150,151,152
150 MODEL AVIATION
Genesis Extreme Electric Retrofit Project report
[[email protected]]
Control Line Aerobatics Bob Hunt
Also included in this column:
• Don’t give up on a model
too quickly
Bob sent a set of Genesis Extreme pencil drawings to his friend, Peter White, in
Australia, and this is the outstanding result. Peter installed a Stalker glow engine in his
version of the model.
Bob debuted his converted Genesis Extreme at
the 2005 FAI Team Trials. He was the first US
pilot to qualify for an FAI team flying an electric
model. At this point the battery was loaded
from the bottom and the AXI 2826/10 was rear
mounted.
The updated Genesis accepts a top-loaded battery and the AXI
2826/10 is now front mounted. The paint trim scheme had to be
modified after the changeover. Bob picked up on the red, white,
and blue trim on the flaps. Way to nail the project, Bob!
BEFORE WE GET back to the essential shop items required for
building a world-beater CL Precision Aerobatics (Stunt) model, I’ll
give you an update on the Genesis Extreme Electric Retrofit
Project.
If you recall, I was retrofitting a front-mounted AXI 2826/10
motor into the model where a rear-mounted AXi had previously
resided. The reason for the changeover was that the rear-mounted
power plant was not lasting more than approximately 70-90 flights
before experiencing bearing failure.
That failure was probably caused by the fact that the motor
weight and induced propeller loads—all forward of the mount—
were producing a cantilever effect and “coning” out the rear
bearing mount; at least that’s the conclusion at which we (Dean
Pappas and I) arrived.
The thought was to front mount the AXi and then install a rear
bearing mount that would support both ends of the motor shaft and
prevent the motor from “flexing.” All that worked fine, but it cost a
bit of weight, added considerable complexity, and made it more
difficult to direct cooling air around the motor and out of the
model.
It was decided to run the AXi without the rear bearing. From
that we learned that by front-mounting the motor we eliminated a
good deal of the cantilever effect.
We ended up running the power plant without the rear bearing
support and now think that the front mounting was all that was
necessary. When the motor was rear mounted, we heard a
pronounced change in the sound of it when each abrupt change of
direction was made, as in the corners of a square. By merely frontmounting
the motor, virtually all of that noise went away.
We reached the conclusion that locating the propeller and spinner
on one side of the mount and the rotating motor can on the other
balanced out the cantilever effect. The jury is still out until we see how
many flights we will get with the front-mounted motor with an
unsupported shaft at the rear. But I’m fairly confident that the problem
is essentially solved.
My very good friend and flying friend, Buddy Wieder, put the rear
bearing mount I have described in his Ryan’s Eagle and flew it several
times with the arrangement in place. The model needed to shed a few
grams in the nose to make it turn a bit better, so Buddy removed the
rear bearing and the attendant plywood yoke in which the bearing
resided.
He has flown the model at least 100 times since then, and the results
so far are good. There has been no bearing failure.
So the Genesis Extreme now has a new motor mount, and it has a
removable top hatch to allow me to top-load the battery. That has made
changing the battery much easier than when I had to invert the model
after every flight and “fold” the electronics back to remove it. It has
also allowed me to mount the battery higher in the airplane.
11sig5.QXD_00MSTRPG.QXD 9/23/10 10:24 AM Page 150
A side benefit is that all of the
“electronics” now reside in the bottom
block, which makes the entire installation
look much more sanitary.
I wanted to be able to mount the battery
higher in the aircraft, because I felt that
there was a vertical CG issue and thought
that mounting the battery higher might fix
it. This particular Genesis has always been
more than a bit roll-trim sensitive, and I
have tried many combinations of flap
tweaks and tip weight in an effort to get the
model to behave properly.
It has always wanted to lift the outside
wing during maneuvers. Whenever I put in
more tip weight to counter this tendency, it
has resulted in a tip “bang” at the corners.
That was frustrating to say the least. With
the battery mounted higher in the model, I
felt that a good deal of the roll problem—
but not all of it—had been eliminated.
The Genesis had also picked up a
tendency to “hunt” in level flight and not
“lock” after a maneuver. I finally started
sighting and measuring to see what the
problem was.
The wing was perfect and had no warps;
of that I was sure. Then I checked the
elevators and found a pronounced upward
curl in the inboard elevator. The curl started
at close to the half-span point and ran up a
good 1/8 inch to the tip! How could I have
missed that?
I bent the inboard elevator down in
relation to the outboard elevator in an effort
to average out the effect of the curl. That
curl was in the direction that would tend to
roll the model to the left and hence lift the
outboard wing, which was the problem I
had long been trying to fix.
With the inboard elevator tweaked down
nearly 3/32 inch, the roll stopped and the
model locked securely upon returning to
level flight after maneuvers. Problem
solved.
With the extreme nose modifications
required to change the model from a bottom
loader to a top loader, it was necessary to
repaint the nose. Matching the original
paint would have been impossible because
of fading from exposure to the sun
throughout the years.
I studied the model and decided to put
red, white, and blue slashes on the nose,
which would complement the red, white,
and blue bars that I had put on the flaps
when I originally painted the Genesis. I had
always liked those bars on Les McDonald’s
Stilettos, and I stole them. I’m glad I did,
because the new nose trim doesn’t look out
of place—too much.
I built the model in 2001, and it has
given me a lot of service but has never been
perfect. I’ve worked on it in many ways to
improve its performance throughout the
years, and that included four different
power trains: two glow and two electric. I
felt that one more major modification was
warranted: to remove the stock elevators
and retrofit new, more accurate ones.
To do this, I cut around the stock hinges
where they were glued into the elevators
and then cut a groove to allow me to
remove them from the horn wire in one
piece. I could then use each elevator as a
template with which to trace a new one on
fresh balsa.
I left the Great Planes Medium Pinned
Hinges in place in the stabilizer and simply
held each new elevator under the hinges to
mark out the position of the hinge pockets.
I finished the new elevators off of the
airplane and then attached them
permanently using RC/56 canopy glue to
secure the hinges into the slots. This
adhesive sticks well to plastics but does not
shrink and cause surface blemishes, as
yellow wood glue does.
The result is a model that finally flies to
my liking. It still looks good and should
have a long life ahead of it—especially now
that it has no-vibration electric power.
I’m going to make one more
modification to this aircraft. With the stocklength
landing gear, it’s unable to swing the
new APC 13 x 4.5P. That propeller has
proven to be an excellent match to the AXi
motor in many other models.
I’m currently running an APC 12 x
6EP. It works fine, but I’m certain that the
13-inch will improve the performance yet
another notch. This will require new
wheel pants to be made, but that’s okay;
the existing ones are getting beaten up
anyway.
wanted to go through all the trials and
tribulations I experienced with the
Genesis Extreme to make a point: that you
should not give up on a model too
quickly. Many that are hard to trim or that
don’t fly as well as you expect might need
a bit of thought and a few small
modifications to make them perform
excellently.
I’ve been asked many times for plans
for this airplane. I’ve run off a few sets of
the pencil drawings from which it was
built but have hesitated to draw it
formally because of the trim problems that
the original displayed.
Now that those problems are fixed and
I know that the design is good, I’ll start on
a set of proper plans. They will feature
both “Glow Nose” and “Electric Nose”
construction details.
I sent one set of pencil drawings to
Peter White in Australia, and he produced
a nice rendition of the model. I’ll end this
month’s columns with a few comments
from Peter. I’ll be back next time with
more shop stuff.
“The Genesis Extreme electric
conversion must have been quite a
project. I envy anyone who can do a job
such as that with no evidence of
‘collateral damage’ … and the outcome
looks great.
“There is a group of guys in New
South Wales who are beginning to work
on electrics. I wouldn’t be surprised to
see two or three at the next Nats. You
obviously haven’t found any real
downsides compared to IC power.
“I have included some shots of a
familiar looking model that I built last
year for the Nats but didn’t get the
opportunity to trim it out and familiarize
myself with it due to constant wind. The
only field I can fly on (legally) during the
week is surrounded by trees which cause
some horrendous turbulence. Flight
trimming there is pointless and rather
dangerous.
“The model, weighing a touch over 56
ounces, is fitted with a Stalker 61LS and
feels quite good in its present state. If the
wind ever slows down enough, and it has
blown quite strongly for the last six
weeks, I’ll get back into more trimming
and see how it turns out.” MA
Sources:
Precision Aerobatics Model Pilots
Association
www.control-line.org
Edition: Model Aviation - 2010/11
Page Numbers: 150,151,152
150 MODEL AVIATION
Genesis Extreme Electric Retrofit Project report
[[email protected]]
Control Line Aerobatics Bob Hunt
Also included in this column:
• Don’t give up on a model
too quickly
Bob sent a set of Genesis Extreme pencil drawings to his friend, Peter White, in
Australia, and this is the outstanding result. Peter installed a Stalker glow engine in his
version of the model.
Bob debuted his converted Genesis Extreme at
the 2005 FAI Team Trials. He was the first US
pilot to qualify for an FAI team flying an electric
model. At this point the battery was loaded
from the bottom and the AXI 2826/10 was rear
mounted.
The updated Genesis accepts a top-loaded battery and the AXI
2826/10 is now front mounted. The paint trim scheme had to be
modified after the changeover. Bob picked up on the red, white,
and blue trim on the flaps. Way to nail the project, Bob!
BEFORE WE GET back to the essential shop items required for
building a world-beater CL Precision Aerobatics (Stunt) model, I’ll
give you an update on the Genesis Extreme Electric Retrofit
Project.
If you recall, I was retrofitting a front-mounted AXI 2826/10
motor into the model where a rear-mounted AXi had previously
resided. The reason for the changeover was that the rear-mounted
power plant was not lasting more than approximately 70-90 flights
before experiencing bearing failure.
That failure was probably caused by the fact that the motor
weight and induced propeller loads—all forward of the mount—
were producing a cantilever effect and “coning” out the rear
bearing mount; at least that’s the conclusion at which we (Dean
Pappas and I) arrived.
The thought was to front mount the AXi and then install a rear
bearing mount that would support both ends of the motor shaft and
prevent the motor from “flexing.” All that worked fine, but it cost a
bit of weight, added considerable complexity, and made it more
difficult to direct cooling air around the motor and out of the
model.
It was decided to run the AXi without the rear bearing. From
that we learned that by front-mounting the motor we eliminated a
good deal of the cantilever effect.
We ended up running the power plant without the rear bearing
support and now think that the front mounting was all that was
necessary. When the motor was rear mounted, we heard a
pronounced change in the sound of it when each abrupt change of
direction was made, as in the corners of a square. By merely frontmounting
the motor, virtually all of that noise went away.
We reached the conclusion that locating the propeller and spinner
on one side of the mount and the rotating motor can on the other
balanced out the cantilever effect. The jury is still out until we see how
many flights we will get with the front-mounted motor with an
unsupported shaft at the rear. But I’m fairly confident that the problem
is essentially solved.
My very good friend and flying friend, Buddy Wieder, put the rear
bearing mount I have described in his Ryan’s Eagle and flew it several
times with the arrangement in place. The model needed to shed a few
grams in the nose to make it turn a bit better, so Buddy removed the
rear bearing and the attendant plywood yoke in which the bearing
resided.
He has flown the model at least 100 times since then, and the results
so far are good. There has been no bearing failure.
So the Genesis Extreme now has a new motor mount, and it has a
removable top hatch to allow me to top-load the battery. That has made
changing the battery much easier than when I had to invert the model
after every flight and “fold” the electronics back to remove it. It has
also allowed me to mount the battery higher in the airplane.
11sig5.QXD_00MSTRPG.QXD 9/23/10 10:24 AM Page 150
A side benefit is that all of the
“electronics” now reside in the bottom
block, which makes the entire installation
look much more sanitary.
I wanted to be able to mount the battery
higher in the aircraft, because I felt that
there was a vertical CG issue and thought
that mounting the battery higher might fix
it. This particular Genesis has always been
more than a bit roll-trim sensitive, and I
have tried many combinations of flap
tweaks and tip weight in an effort to get the
model to behave properly.
It has always wanted to lift the outside
wing during maneuvers. Whenever I put in
more tip weight to counter this tendency, it
has resulted in a tip “bang” at the corners.
That was frustrating to say the least. With
the battery mounted higher in the model, I
felt that a good deal of the roll problem—
but not all of it—had been eliminated.
The Genesis had also picked up a
tendency to “hunt” in level flight and not
“lock” after a maneuver. I finally started
sighting and measuring to see what the
problem was.
The wing was perfect and had no warps;
of that I was sure. Then I checked the
elevators and found a pronounced upward
curl in the inboard elevator. The curl started
at close to the half-span point and ran up a
good 1/8 inch to the tip! How could I have
missed that?
I bent the inboard elevator down in
relation to the outboard elevator in an effort
to average out the effect of the curl. That
curl was in the direction that would tend to
roll the model to the left and hence lift the
outboard wing, which was the problem I
had long been trying to fix.
With the inboard elevator tweaked down
nearly 3/32 inch, the roll stopped and the
model locked securely upon returning to
level flight after maneuvers. Problem
solved.
With the extreme nose modifications
required to change the model from a bottom
loader to a top loader, it was necessary to
repaint the nose. Matching the original
paint would have been impossible because
of fading from exposure to the sun
throughout the years.
I studied the model and decided to put
red, white, and blue slashes on the nose,
which would complement the red, white,
and blue bars that I had put on the flaps
when I originally painted the Genesis. I had
always liked those bars on Les McDonald’s
Stilettos, and I stole them. I’m glad I did,
because the new nose trim doesn’t look out
of place—too much.
I built the model in 2001, and it has
given me a lot of service but has never been
perfect. I’ve worked on it in many ways to
improve its performance throughout the
years, and that included four different
power trains: two glow and two electric. I
felt that one more major modification was
warranted: to remove the stock elevators
and retrofit new, more accurate ones.
To do this, I cut around the stock hinges
where they were glued into the elevators
and then cut a groove to allow me to
remove them from the horn wire in one
piece. I could then use each elevator as a
template with which to trace a new one on
fresh balsa.
I left the Great Planes Medium Pinned
Hinges in place in the stabilizer and simply
held each new elevator under the hinges to
mark out the position of the hinge pockets.
I finished the new elevators off of the
airplane and then attached them
permanently using RC/56 canopy glue to
secure the hinges into the slots. This
adhesive sticks well to plastics but does not
shrink and cause surface blemishes, as
yellow wood glue does.
The result is a model that finally flies to
my liking. It still looks good and should
have a long life ahead of it—especially now
that it has no-vibration electric power.
I’m going to make one more
modification to this aircraft. With the stocklength
landing gear, it’s unable to swing the
new APC 13 x 4.5P. That propeller has
proven to be an excellent match to the AXi
motor in many other models.
I’m currently running an APC 12 x
6EP. It works fine, but I’m certain that the
13-inch will improve the performance yet
another notch. This will require new
wheel pants to be made, but that’s okay;
the existing ones are getting beaten up
anyway.
wanted to go through all the trials and
tribulations I experienced with the
Genesis Extreme to make a point: that you
should not give up on a model too
quickly. Many that are hard to trim or that
don’t fly as well as you expect might need
a bit of thought and a few small
modifications to make them perform
excellently.
I’ve been asked many times for plans
for this airplane. I’ve run off a few sets of
the pencil drawings from which it was
built but have hesitated to draw it
formally because of the trim problems that
the original displayed.
Now that those problems are fixed and
I know that the design is good, I’ll start on
a set of proper plans. They will feature
both “Glow Nose” and “Electric Nose”
construction details.
I sent one set of pencil drawings to
Peter White in Australia, and he produced
a nice rendition of the model. I’ll end this
month’s columns with a few comments
from Peter. I’ll be back next time with
more shop stuff.
“The Genesis Extreme electric
conversion must have been quite a
project. I envy anyone who can do a job
such as that with no evidence of
‘collateral damage’ … and the outcome
looks great.
“There is a group of guys in New
South Wales who are beginning to work
on electrics. I wouldn’t be surprised to
see two or three at the next Nats. You
obviously haven’t found any real
downsides compared to IC power.
“I have included some shots of a
familiar looking model that I built last
year for the Nats but didn’t get the
opportunity to trim it out and familiarize
myself with it due to constant wind. The
only field I can fly on (legally) during the
week is surrounded by trees which cause
some horrendous turbulence. Flight
trimming there is pointless and rather
dangerous.
“The model, weighing a touch over 56
ounces, is fitted with a Stalker 61LS and
feels quite good in its present state. If the
wind ever slows down enough, and it has
blown quite strongly for the last six
weeks, I’ll get back into more trimming
and see how it turns out.” MA
Sources:
Precision Aerobatics Model Pilots
Association
www.control-line.org
