150 MODEL AVIATION
Remembering Vernon Hacker
Free Flight Indoor John Kagan
[[email protected]]
Also included in this column:
• All about partial-motor testing
• Indoor National Cup report
• Three-views update
• Photo-credit makeup
• New toy from F1D.biz
How do these F1D fliers get their models dialed in precisely at the roof? See the
column text for the secret. Photo by Max Zaluska.
Vern Hacker at West Baden IN with a
balloon that only a few fliers he has helped
through the years signed. Zaluska photo.
The author’s adjustable partial-motor dummy stick. See column text for details.
THE INDOOR COMMUNITY lost a wellrespected
member, tireless supporter, and
good friend when Vernon Hacker passed
away this winter. Known affectionately as
“Doc” or “Hack” (he was both a surgeon and
a golfer), he loved model airplanes and flew
them his whole life. He enjoyed competing
but was even more known for the support,
guidance, and encouragement he gave to
many in the hobby.
Doc took me under his wing when I
moved to Cleveland, Ohio, in 1998. We
poured microfilm in his basement, realizing
the strength of the fumes only after we
returned back from a trip upstairs. (I wonder
how many brain cells I lost on that project!)
When the models covered with the film
we made together won the next F1D World
Championships, he was not so much thrilled
as he was quietly satisfied—like a proud
parent.
Doc touched many modelers’ lives, with a
particular emphasis on beginners and Juniors.
He mentored countless fliers (many who are
top-level competitors today), traveled to
several World Championships as a supporter,
raised funds for the Junior team, and when his
mobility was restricted by medical equipment,
he was the first to try to hook up new
modelers with mentors wherever they lived.
At Doc’s memorial service I learned that
his beneficence extended well beyond the
model-airplane world to chief of surgery,
community pillar, and even barbershop
quartets! He was opinionated, sharp-witted,
and quick to speak his mind, but he had a
great heart, and those of us who had the honor
of knowing him will miss him dearly.
Partial Motors: Last time I wrote about
partial-motor testing and some of the
problems we experienced at the F1D Team
Selection. But what exactly are partial motors
and why do some people get more accurate
results with them than others?
Partial-motor testing is a technique that
provides several important benefits in any
Indoor FF event, from Science Olympiad to
the F1D World Championships and
everything in between. It allows safer testing
by keeping well clear of the ceiling, obtaining
quicker feedback on adjustments via shorter
flight times, using smaller test sites, and
preserving valuable rubber through smaller
motors.
A shorter motor is used with a dummy
stick to take up some portion of the distance
between the propeller hook and the rear hook
and provide its share of the weight.
If I wanted to do one-quarter partial motors
04sig5.QXD 2/25/08 9:33 AM Page 150
on my F1D, I would use a dummy stick that was three-quarters the
length between the hooks (my hook to hook is 9.5 inches, so the
dummy stick would be 7.125 inches) and weighed three-quarters of a
full motor. (A full motor is .6 gram, so the dummy stick would weigh
.45 gram.) My one-quarter motor would weigh one-quarter of a full
motor, or .15 gram.
I would wind in one-quarter the amount of turn the full motor
would take (roughly 400 turns), up to the same max torque. The
resulting flight would climb to one-quarter the altitude of the full motor
and do one-quarter the time.
That’s quick and easy! You can use one-third motors, one-sixth
motors, or whatever other fraction you choose.
However, you have to make sure you are as accurate as possible
with all the variables to get good results. Any errors are multiplied and
can produce misleading results, resulting in poor flights, hung models,
or even broken motorsticks. I’m going to share a few “tricks” to get
partial-motor predictions that fall within seconds of the full-motor
flights.
Measure the ceiling height and your partial-motor altitude. Don’t
rely on the promoter’s statistics; use your balloon and line to measure
the actual height of the ceiling. Then calculate where you want to safely
fly and set your balloon to the appropriate target height.
During the partial-motor flights, move your balloon close to the
circle and step back to get a good visual angle. This way you can get an
accurate indication of where your full-motor flight will end up and
whether or not you’re hitting your target partial-motor altitude.
Carefully check your dummy stick’s weight. For events without
motor-weight limitation, weight the partial motor accurately and ballast
the dummy stick appropriately each time you change the motor.
In events with a motor limit, such as F1D, you won’t have to change
the ballast, but you still need to check the dummy stick’s weight
regularly. You’d be surprised by how much mass it can accumulate
through regular handling.
Set the dummy stick’s length accurately. Some people have
complained that partial motors produce more “pull” between the hooks,
resulting in motorsticks that break with partial motors but not full
motors. Physics says that the tension and torque will be the same with
partial motors (assuming all the other stuff is proportional), so there
must be something else at work.
I’m guessing that their dummy sticks and/or motors are too short.
Measure carefully and avoid this trouble!
It is common to have variations in hook-to-hook length between
models, and even between propellers (because of differences in the
propeller-shaft length). Fliers often have a box full of dummy sticks of
various lengths and strengths for their various models. Think about
making a dummy stick for each propeller/model combination.
As an alternative I came up with an adjustable-length dummy stick
that allows me to change the measurements to suit any model. (See the
picture.) If you go that route, make sure to construct a spare or two. I
caused myself a bunch of grief at the last World Championships when
my only dummy stick broke.
Watch your launch and “landing” height. You won’t get four times
the distance from a shoulder-height launch to a floor landing when you
do a full-motor flight. To compensate, some people kneel and launch
their partial-motor flights near the floor. Then they can let the model
land on the floor at the end of the flight.
I don’t like doing that much exercise, so I still launch at shoulder
height. But then I catch the model near shoulder height on the way
down rather than letting it go all the way to the floor.
These tips should give you a good starting point. For further finetuning,
do a bunch of partial- and full-motor flights and observe the
correlation. If they aren’t spot on, check your procedures and make
adjustments until they match.
Many people attribute variations to “boundary layers,” “thermals,”
or “heat near the roof.” I’ve experienced each of these on occasion, but
I don’t think they are quite as prevalent as people tend to think. (Venues
such as the Buffalo Bills field house excluded.) Pay attention to the
details and you can get the accuracy you want. Try it out!
Indoor National Cup: Jim Buxton sent in the following report.
“The 2007 Indoor National Cup season has come to a close!
“The Indoor National Cups are sponsored by the National Free
Flight Society. The basic idea is to allow indoorists from across the
country to compete in a year long points series for top honors in each of
the two major disciplines, Indoor Rubber and Indoor Glider.
April 2008 151
The author’s Hand-Launched
Stick on a one-quarter-motor
test, looking for more than 15
minutes. Zaluska photo.
Steve Brown, a three-time F1D World
Champion, does partial-motor tests too.
Zaluska photo.
Current F1D WC Larry Cailliau’s model
on a partial-motor flight. Look closely to
see the red dummy stick. Zaluska photo.
Max Zaluska’s F1D gets in on
the partial-motor action.
Zaluska photo.
04sig5.QXD 2/25/08 9:33 AM Page 151
Blade Holder: Are you having trouble finding
a gift for the modeler in your life who already
has everything? Or perhaps you’re the one
building and you enjoy those little luxuries that
make the process more fun.
Tim Goldstein’s A2Z CNC comes to the
rescue with its latest gadget: a CNC-machined,
hard-anodized, Teflon-impregnated, aluminum
blade holder for micrometer balsa strippers
such as Ray Harlan’s. This hefty block has a
nice feel and features a Turcite Teflon strip on
the side that runs along the straightedge with a
1° blade angle that is designed to help keep thin
cuts from wandering.
Although this device isn’t on the list of bare
necessities for newcomers, it does make a nice
treat for the dedicated modelers. And at $25 it’s
one of the more economical splurges available.
You can find the blade holder and other neat
things at A2Z CNC or F1D.biz.
USIC and Kibbie Dome Annual: Don’t forget
to register for the US Indoor Championships
(USIC) and/or Kibbie Dome Annual! Look on
the AMA Web site for USIC information, and
contact Andrew Tagliafico about the Kibbie
Dome Annual. MA
Sources:
A2Z CNC
(877) 754-7465
www.a2zcnc.com
www.fid.biz
AMA
(765) 287-1256
www.modelaircraft.org
Andrew Tagliafico
[email protected]
Indoor FF three-view request form
www.modelaircraft.org/PDF-files/319.pdf
Indoor News
www.indoornews.com
Max Zaluska’s photos
http://community.webshots.com/user/
FlyEZB
Ray Harlan micrometer balsa stripper
(508) 358-4013
www.indoorduration.com/HarlanBrochure.htm
“There were seven regional contests to
choose from this year, which was down two
from 2006 unfortunately. Up to six regional
events can be used by each flier for points in
addition to either of the two ‘biggies,’ The
Kibbie Dome annual or The United States
Indoor Championships. Contestants that place
in the top five in any event will receive
National Cup Points. The points are weighted
based upon the number of entrants in the
particular event.
“Rob Romash beat out Tom Sova for top
spot in the Rubber event, which includes F1L,
Limited Pennyplane, and MiniStick. Rob
placed well in both of his local regional
contests (Colorado Springs) and traveled to
Kent, Ohio to help his score. Those three
regional events plus a strong showing at the
Kibbie Dome Annual gave him a point total
of 281.
“The Indoor Glider Cup pulls scores from
Hand Lunched Glider, Standard Catapult, and
Unlimited Catapult. Rob Romash came within
three points of taking both cups, but was
edged out by perennial winner Kurt Krempetz
for the Glider honors.
“Kurt was one of few people to achieve
three scores at one location. It should be noted
that only two scores per location count
towards an individual’s point totals. Kurt had
five regional scores plus his scores at USIC to
take the win with 271 total points.
“Congratulations to all of the winners!
“Contest directors, now is the time to get
your 2008 event added to the schedule. You
never know what out-of-towner may travel
across country in hopes of picking up a few
more points! Information and applications for
inclusion can be found at www.freeflight.org/
competition/IndoorNationalCup/info.htm.”
Following are the final scores for the 2007
Indoor National Cup.
Glider Points
1. Kurt Krempetz, 271
2. R. Romash, 268
3. W. Gowen, 216
4. J. Buxton, 161
5. B. Miller, 121
6. D. DeLoach, 79
7. T. Reynolds, 73
8. M. Covington, 63
9. E. Berray, 61
10. Ken Krempetz, 59
Rubber Points
1. R. Romash, 281
2. T. Sova, 190
3. W. Gowen, 165
4. J. Richmond, 113
5. L. Loucka, 97
6. W. Van Gorder, 94
7. R. Warmann, 90
8. N. Ray, 70
9. S. Fultz, 69
10. W. Leppard, 67
Record-Setting Three-Views: If you’ve
been following this column, you may know
that for many years I’ve been championing
an effort to make the three-view drawings
submitted with Indoor FF record
applications more readily available to the
membership. We’ve had a few bureaucratic
steps backward along the way, but there is
now an official form with which you can
request copies.
The procedure is still far short of my
vision of a Web site with a catalog of
scanned three-view images, and the cost
($10 for the first plans and $5 for additional
drawings) is a bit steep, but at least they are
accessible. Head to the AMA Web site to
get the document.
Those who are looking for more
economical access to great designs can
check out Jeff Hood’s Indoor News Web
site. It has an online Indoor FF record list
with three-views attached to several of the
entries. The site also features a separate
“Downloads” area with many more plans
and three-views. There’s lots of great info
here, and it’s all free.
If you have set a record, have a niceflying
model, or just want to share your
efforts, consider sending an image to Jeff.
He can post it along with the others. There’s
nothing like a good grassroots effort to cut
through the red tape!
Photo Credits: It seems that the credits for
last column’s photos got lost in the mix, so
I’m sending recognition to Max Zaluska for
those pictures. In addition to being a fine
model-airplane craftsman and pilot, Max has
talent with a camera.
You can check out more of his image
wizardry online. He has many modelairplane
shots from a variety of events, as
well as other interesting subjects.
152 MODEL AVIATION
04sig5.QXD 2/25/08 9:34 AM Page 152
Edition: Model Aviation - 2008/04
Page Numbers: 150,151,152
Edition: Model Aviation - 2008/04
Page Numbers: 150,151,152
150 MODEL AVIATION
Remembering Vernon Hacker
Free Flight Indoor John Kagan
[[email protected]]
Also included in this column:
• All about partial-motor testing
• Indoor National Cup report
• Three-views update
• Photo-credit makeup
• New toy from F1D.biz
How do these F1D fliers get their models dialed in precisely at the roof? See the
column text for the secret. Photo by Max Zaluska.
Vern Hacker at West Baden IN with a
balloon that only a few fliers he has helped
through the years signed. Zaluska photo.
The author’s adjustable partial-motor dummy stick. See column text for details.
THE INDOOR COMMUNITY lost a wellrespected
member, tireless supporter, and
good friend when Vernon Hacker passed
away this winter. Known affectionately as
“Doc” or “Hack” (he was both a surgeon and
a golfer), he loved model airplanes and flew
them his whole life. He enjoyed competing
but was even more known for the support,
guidance, and encouragement he gave to
many in the hobby.
Doc took me under his wing when I
moved to Cleveland, Ohio, in 1998. We
poured microfilm in his basement, realizing
the strength of the fumes only after we
returned back from a trip upstairs. (I wonder
how many brain cells I lost on that project!)
When the models covered with the film
we made together won the next F1D World
Championships, he was not so much thrilled
as he was quietly satisfied—like a proud
parent.
Doc touched many modelers’ lives, with a
particular emphasis on beginners and Juniors.
He mentored countless fliers (many who are
top-level competitors today), traveled to
several World Championships as a supporter,
raised funds for the Junior team, and when his
mobility was restricted by medical equipment,
he was the first to try to hook up new
modelers with mentors wherever they lived.
At Doc’s memorial service I learned that
his beneficence extended well beyond the
model-airplane world to chief of surgery,
community pillar, and even barbershop
quartets! He was opinionated, sharp-witted,
and quick to speak his mind, but he had a
great heart, and those of us who had the honor
of knowing him will miss him dearly.
Partial Motors: Last time I wrote about
partial-motor testing and some of the
problems we experienced at the F1D Team
Selection. But what exactly are partial motors
and why do some people get more accurate
results with them than others?
Partial-motor testing is a technique that
provides several important benefits in any
Indoor FF event, from Science Olympiad to
the F1D World Championships and
everything in between. It allows safer testing
by keeping well clear of the ceiling, obtaining
quicker feedback on adjustments via shorter
flight times, using smaller test sites, and
preserving valuable rubber through smaller
motors.
A shorter motor is used with a dummy
stick to take up some portion of the distance
between the propeller hook and the rear hook
and provide its share of the weight.
If I wanted to do one-quarter partial motors
04sig5.QXD 2/25/08 9:33 AM Page 150
on my F1D, I would use a dummy stick that was three-quarters the
length between the hooks (my hook to hook is 9.5 inches, so the
dummy stick would be 7.125 inches) and weighed three-quarters of a
full motor. (A full motor is .6 gram, so the dummy stick would weigh
.45 gram.) My one-quarter motor would weigh one-quarter of a full
motor, or .15 gram.
I would wind in one-quarter the amount of turn the full motor
would take (roughly 400 turns), up to the same max torque. The
resulting flight would climb to one-quarter the altitude of the full motor
and do one-quarter the time.
That’s quick and easy! You can use one-third motors, one-sixth
motors, or whatever other fraction you choose.
However, you have to make sure you are as accurate as possible
with all the variables to get good results. Any errors are multiplied and
can produce misleading results, resulting in poor flights, hung models,
or even broken motorsticks. I’m going to share a few “tricks” to get
partial-motor predictions that fall within seconds of the full-motor
flights.
Measure the ceiling height and your partial-motor altitude. Don’t
rely on the promoter’s statistics; use your balloon and line to measure
the actual height of the ceiling. Then calculate where you want to safely
fly and set your balloon to the appropriate target height.
During the partial-motor flights, move your balloon close to the
circle and step back to get a good visual angle. This way you can get an
accurate indication of where your full-motor flight will end up and
whether or not you’re hitting your target partial-motor altitude.
Carefully check your dummy stick’s weight. For events without
motor-weight limitation, weight the partial motor accurately and ballast
the dummy stick appropriately each time you change the motor.
In events with a motor limit, such as F1D, you won’t have to change
the ballast, but you still need to check the dummy stick’s weight
regularly. You’d be surprised by how much mass it can accumulate
through regular handling.
Set the dummy stick’s length accurately. Some people have
complained that partial motors produce more “pull” between the hooks,
resulting in motorsticks that break with partial motors but not full
motors. Physics says that the tension and torque will be the same with
partial motors (assuming all the other stuff is proportional), so there
must be something else at work.
I’m guessing that their dummy sticks and/or motors are too short.
Measure carefully and avoid this trouble!
It is common to have variations in hook-to-hook length between
models, and even between propellers (because of differences in the
propeller-shaft length). Fliers often have a box full of dummy sticks of
various lengths and strengths for their various models. Think about
making a dummy stick for each propeller/model combination.
As an alternative I came up with an adjustable-length dummy stick
that allows me to change the measurements to suit any model. (See the
picture.) If you go that route, make sure to construct a spare or two. I
caused myself a bunch of grief at the last World Championships when
my only dummy stick broke.
Watch your launch and “landing” height. You won’t get four times
the distance from a shoulder-height launch to a floor landing when you
do a full-motor flight. To compensate, some people kneel and launch
their partial-motor flights near the floor. Then they can let the model
land on the floor at the end of the flight.
I don’t like doing that much exercise, so I still launch at shoulder
height. But then I catch the model near shoulder height on the way
down rather than letting it go all the way to the floor.
These tips should give you a good starting point. For further finetuning,
do a bunch of partial- and full-motor flights and observe the
correlation. If they aren’t spot on, check your procedures and make
adjustments until they match.
Many people attribute variations to “boundary layers,” “thermals,”
or “heat near the roof.” I’ve experienced each of these on occasion, but
I don’t think they are quite as prevalent as people tend to think. (Venues
such as the Buffalo Bills field house excluded.) Pay attention to the
details and you can get the accuracy you want. Try it out!
Indoor National Cup: Jim Buxton sent in the following report.
“The 2007 Indoor National Cup season has come to a close!
“The Indoor National Cups are sponsored by the National Free
Flight Society. The basic idea is to allow indoorists from across the
country to compete in a year long points series for top honors in each of
the two major disciplines, Indoor Rubber and Indoor Glider.
April 2008 151
The author’s Hand-Launched
Stick on a one-quarter-motor
test, looking for more than 15
minutes. Zaluska photo.
Steve Brown, a three-time F1D World
Champion, does partial-motor tests too.
Zaluska photo.
Current F1D WC Larry Cailliau’s model
on a partial-motor flight. Look closely to
see the red dummy stick. Zaluska photo.
Max Zaluska’s F1D gets in on
the partial-motor action.
Zaluska photo.
04sig5.QXD 2/25/08 9:33 AM Page 151
Blade Holder: Are you having trouble finding
a gift for the modeler in your life who already
has everything? Or perhaps you’re the one
building and you enjoy those little luxuries that
make the process more fun.
Tim Goldstein’s A2Z CNC comes to the
rescue with its latest gadget: a CNC-machined,
hard-anodized, Teflon-impregnated, aluminum
blade holder for micrometer balsa strippers
such as Ray Harlan’s. This hefty block has a
nice feel and features a Turcite Teflon strip on
the side that runs along the straightedge with a
1° blade angle that is designed to help keep thin
cuts from wandering.
Although this device isn’t on the list of bare
necessities for newcomers, it does make a nice
treat for the dedicated modelers. And at $25 it’s
one of the more economical splurges available.
You can find the blade holder and other neat
things at A2Z CNC or F1D.biz.
USIC and Kibbie Dome Annual: Don’t forget
to register for the US Indoor Championships
(USIC) and/or Kibbie Dome Annual! Look on
the AMA Web site for USIC information, and
contact Andrew Tagliafico about the Kibbie
Dome Annual. MA
Sources:
A2Z CNC
(877) 754-7465
www.a2zcnc.com
www.fid.biz
AMA
(765) 287-1256
www.modelaircraft.org
Andrew Tagliafico
[email protected]
Indoor FF three-view request form
www.modelaircraft.org/PDF-files/319.pdf
Indoor News
www.indoornews.com
Max Zaluska’s photos
http://community.webshots.com/user/
FlyEZB
Ray Harlan micrometer balsa stripper
(508) 358-4013
www.indoorduration.com/HarlanBrochure.htm
“There were seven regional contests to
choose from this year, which was down two
from 2006 unfortunately. Up to six regional
events can be used by each flier for points in
addition to either of the two ‘biggies,’ The
Kibbie Dome annual or The United States
Indoor Championships. Contestants that place
in the top five in any event will receive
National Cup Points. The points are weighted
based upon the number of entrants in the
particular event.
“Rob Romash beat out Tom Sova for top
spot in the Rubber event, which includes F1L,
Limited Pennyplane, and MiniStick. Rob
placed well in both of his local regional
contests (Colorado Springs) and traveled to
Kent, Ohio to help his score. Those three
regional events plus a strong showing at the
Kibbie Dome Annual gave him a point total
of 281.
“The Indoor Glider Cup pulls scores from
Hand Lunched Glider, Standard Catapult, and
Unlimited Catapult. Rob Romash came within
three points of taking both cups, but was
edged out by perennial winner Kurt Krempetz
for the Glider honors.
“Kurt was one of few people to achieve
three scores at one location. It should be noted
that only two scores per location count
towards an individual’s point totals. Kurt had
five regional scores plus his scores at USIC to
take the win with 271 total points.
“Congratulations to all of the winners!
“Contest directors, now is the time to get
your 2008 event added to the schedule. You
never know what out-of-towner may travel
across country in hopes of picking up a few
more points! Information and applications for
inclusion can be found at www.freeflight.org/
competition/IndoorNationalCup/info.htm.”
Following are the final scores for the 2007
Indoor National Cup.
Glider Points
1. Kurt Krempetz, 271
2. R. Romash, 268
3. W. Gowen, 216
4. J. Buxton, 161
5. B. Miller, 121
6. D. DeLoach, 79
7. T. Reynolds, 73
8. M. Covington, 63
9. E. Berray, 61
10. Ken Krempetz, 59
Rubber Points
1. R. Romash, 281
2. T. Sova, 190
3. W. Gowen, 165
4. J. Richmond, 113
5. L. Loucka, 97
6. W. Van Gorder, 94
7. R. Warmann, 90
8. N. Ray, 70
9. S. Fultz, 69
10. W. Leppard, 67
Record-Setting Three-Views: If you’ve
been following this column, you may know
that for many years I’ve been championing
an effort to make the three-view drawings
submitted with Indoor FF record
applications more readily available to the
membership. We’ve had a few bureaucratic
steps backward along the way, but there is
now an official form with which you can
request copies.
The procedure is still far short of my
vision of a Web site with a catalog of
scanned three-view images, and the cost
($10 for the first plans and $5 for additional
drawings) is a bit steep, but at least they are
accessible. Head to the AMA Web site to
get the document.
Those who are looking for more
economical access to great designs can
check out Jeff Hood’s Indoor News Web
site. It has an online Indoor FF record list
with three-views attached to several of the
entries. The site also features a separate
“Downloads” area with many more plans
and three-views. There’s lots of great info
here, and it’s all free.
If you have set a record, have a niceflying
model, or just want to share your
efforts, consider sending an image to Jeff.
He can post it along with the others. There’s
nothing like a good grassroots effort to cut
through the red tape!
Photo Credits: It seems that the credits for
last column’s photos got lost in the mix, so
I’m sending recognition to Max Zaluska for
those pictures. In addition to being a fine
model-airplane craftsman and pilot, Max has
talent with a camera.
You can check out more of his image
wizardry online. He has many modelairplane
shots from a variety of events, as
well as other interesting subjects.
152 MODEL AVIATION
04sig5.QXD 2/25/08 9:34 AM Page 152
Edition: Model Aviation - 2008/04
Page Numbers: 150,151,152
150 MODEL AVIATION
Remembering Vernon Hacker
Free Flight Indoor John Kagan
[[email protected]]
Also included in this column:
• All about partial-motor testing
• Indoor National Cup report
• Three-views update
• Photo-credit makeup
• New toy from F1D.biz
How do these F1D fliers get their models dialed in precisely at the roof? See the
column text for the secret. Photo by Max Zaluska.
Vern Hacker at West Baden IN with a
balloon that only a few fliers he has helped
through the years signed. Zaluska photo.
The author’s adjustable partial-motor dummy stick. See column text for details.
THE INDOOR COMMUNITY lost a wellrespected
member, tireless supporter, and
good friend when Vernon Hacker passed
away this winter. Known affectionately as
“Doc” or “Hack” (he was both a surgeon and
a golfer), he loved model airplanes and flew
them his whole life. He enjoyed competing
but was even more known for the support,
guidance, and encouragement he gave to
many in the hobby.
Doc took me under his wing when I
moved to Cleveland, Ohio, in 1998. We
poured microfilm in his basement, realizing
the strength of the fumes only after we
returned back from a trip upstairs. (I wonder
how many brain cells I lost on that project!)
When the models covered with the film
we made together won the next F1D World
Championships, he was not so much thrilled
as he was quietly satisfied—like a proud
parent.
Doc touched many modelers’ lives, with a
particular emphasis on beginners and Juniors.
He mentored countless fliers (many who are
top-level competitors today), traveled to
several World Championships as a supporter,
raised funds for the Junior team, and when his
mobility was restricted by medical equipment,
he was the first to try to hook up new
modelers with mentors wherever they lived.
At Doc’s memorial service I learned that
his beneficence extended well beyond the
model-airplane world to chief of surgery,
community pillar, and even barbershop
quartets! He was opinionated, sharp-witted,
and quick to speak his mind, but he had a
great heart, and those of us who had the honor
of knowing him will miss him dearly.
Partial Motors: Last time I wrote about
partial-motor testing and some of the
problems we experienced at the F1D Team
Selection. But what exactly are partial motors
and why do some people get more accurate
results with them than others?
Partial-motor testing is a technique that
provides several important benefits in any
Indoor FF event, from Science Olympiad to
the F1D World Championships and
everything in between. It allows safer testing
by keeping well clear of the ceiling, obtaining
quicker feedback on adjustments via shorter
flight times, using smaller test sites, and
preserving valuable rubber through smaller
motors.
A shorter motor is used with a dummy
stick to take up some portion of the distance
between the propeller hook and the rear hook
and provide its share of the weight.
If I wanted to do one-quarter partial motors
04sig5.QXD 2/25/08 9:33 AM Page 150
on my F1D, I would use a dummy stick that was three-quarters the
length between the hooks (my hook to hook is 9.5 inches, so the
dummy stick would be 7.125 inches) and weighed three-quarters of a
full motor. (A full motor is .6 gram, so the dummy stick would weigh
.45 gram.) My one-quarter motor would weigh one-quarter of a full
motor, or .15 gram.
I would wind in one-quarter the amount of turn the full motor
would take (roughly 400 turns), up to the same max torque. The
resulting flight would climb to one-quarter the altitude of the full motor
and do one-quarter the time.
That’s quick and easy! You can use one-third motors, one-sixth
motors, or whatever other fraction you choose.
However, you have to make sure you are as accurate as possible
with all the variables to get good results. Any errors are multiplied and
can produce misleading results, resulting in poor flights, hung models,
or even broken motorsticks. I’m going to share a few “tricks” to get
partial-motor predictions that fall within seconds of the full-motor
flights.
Measure the ceiling height and your partial-motor altitude. Don’t
rely on the promoter’s statistics; use your balloon and line to measure
the actual height of the ceiling. Then calculate where you want to safely
fly and set your balloon to the appropriate target height.
During the partial-motor flights, move your balloon close to the
circle and step back to get a good visual angle. This way you can get an
accurate indication of where your full-motor flight will end up and
whether or not you’re hitting your target partial-motor altitude.
Carefully check your dummy stick’s weight. For events without
motor-weight limitation, weight the partial motor accurately and ballast
the dummy stick appropriately each time you change the motor.
In events with a motor limit, such as F1D, you won’t have to change
the ballast, but you still need to check the dummy stick’s weight
regularly. You’d be surprised by how much mass it can accumulate
through regular handling.
Set the dummy stick’s length accurately. Some people have
complained that partial motors produce more “pull” between the hooks,
resulting in motorsticks that break with partial motors but not full
motors. Physics says that the tension and torque will be the same with
partial motors (assuming all the other stuff is proportional), so there
must be something else at work.
I’m guessing that their dummy sticks and/or motors are too short.
Measure carefully and avoid this trouble!
It is common to have variations in hook-to-hook length between
models, and even between propellers (because of differences in the
propeller-shaft length). Fliers often have a box full of dummy sticks of
various lengths and strengths for their various models. Think about
making a dummy stick for each propeller/model combination.
As an alternative I came up with an adjustable-length dummy stick
that allows me to change the measurements to suit any model. (See the
picture.) If you go that route, make sure to construct a spare or two. I
caused myself a bunch of grief at the last World Championships when
my only dummy stick broke.
Watch your launch and “landing” height. You won’t get four times
the distance from a shoulder-height launch to a floor landing when you
do a full-motor flight. To compensate, some people kneel and launch
their partial-motor flights near the floor. Then they can let the model
land on the floor at the end of the flight.
I don’t like doing that much exercise, so I still launch at shoulder
height. But then I catch the model near shoulder height on the way
down rather than letting it go all the way to the floor.
These tips should give you a good starting point. For further finetuning,
do a bunch of partial- and full-motor flights and observe the
correlation. If they aren’t spot on, check your procedures and make
adjustments until they match.
Many people attribute variations to “boundary layers,” “thermals,”
or “heat near the roof.” I’ve experienced each of these on occasion, but
I don’t think they are quite as prevalent as people tend to think. (Venues
such as the Buffalo Bills field house excluded.) Pay attention to the
details and you can get the accuracy you want. Try it out!
Indoor National Cup: Jim Buxton sent in the following report.
“The 2007 Indoor National Cup season has come to a close!
“The Indoor National Cups are sponsored by the National Free
Flight Society. The basic idea is to allow indoorists from across the
country to compete in a year long points series for top honors in each of
the two major disciplines, Indoor Rubber and Indoor Glider.
April 2008 151
The author’s Hand-Launched
Stick on a one-quarter-motor
test, looking for more than 15
minutes. Zaluska photo.
Steve Brown, a three-time F1D World
Champion, does partial-motor tests too.
Zaluska photo.
Current F1D WC Larry Cailliau’s model
on a partial-motor flight. Look closely to
see the red dummy stick. Zaluska photo.
Max Zaluska’s F1D gets in on
the partial-motor action.
Zaluska photo.
04sig5.QXD 2/25/08 9:33 AM Page 151
Blade Holder: Are you having trouble finding
a gift for the modeler in your life who already
has everything? Or perhaps you’re the one
building and you enjoy those little luxuries that
make the process more fun.
Tim Goldstein’s A2Z CNC comes to the
rescue with its latest gadget: a CNC-machined,
hard-anodized, Teflon-impregnated, aluminum
blade holder for micrometer balsa strippers
such as Ray Harlan’s. This hefty block has a
nice feel and features a Turcite Teflon strip on
the side that runs along the straightedge with a
1° blade angle that is designed to help keep thin
cuts from wandering.
Although this device isn’t on the list of bare
necessities for newcomers, it does make a nice
treat for the dedicated modelers. And at $25 it’s
one of the more economical splurges available.
You can find the blade holder and other neat
things at A2Z CNC or F1D.biz.
USIC and Kibbie Dome Annual: Don’t forget
to register for the US Indoor Championships
(USIC) and/or Kibbie Dome Annual! Look on
the AMA Web site for USIC information, and
contact Andrew Tagliafico about the Kibbie
Dome Annual. MA
Sources:
A2Z CNC
(877) 754-7465
www.a2zcnc.com
www.fid.biz
AMA
(765) 287-1256
www.modelaircraft.org
Andrew Tagliafico
[email protected]
Indoor FF three-view request form
www.modelaircraft.org/PDF-files/319.pdf
Indoor News
www.indoornews.com
Max Zaluska’s photos
http://community.webshots.com/user/
FlyEZB
Ray Harlan micrometer balsa stripper
(508) 358-4013
www.indoorduration.com/HarlanBrochure.htm
“There were seven regional contests to
choose from this year, which was down two
from 2006 unfortunately. Up to six regional
events can be used by each flier for points in
addition to either of the two ‘biggies,’ The
Kibbie Dome annual or The United States
Indoor Championships. Contestants that place
in the top five in any event will receive
National Cup Points. The points are weighted
based upon the number of entrants in the
particular event.
“Rob Romash beat out Tom Sova for top
spot in the Rubber event, which includes F1L,
Limited Pennyplane, and MiniStick. Rob
placed well in both of his local regional
contests (Colorado Springs) and traveled to
Kent, Ohio to help his score. Those three
regional events plus a strong showing at the
Kibbie Dome Annual gave him a point total
of 281.
“The Indoor Glider Cup pulls scores from
Hand Lunched Glider, Standard Catapult, and
Unlimited Catapult. Rob Romash came within
three points of taking both cups, but was
edged out by perennial winner Kurt Krempetz
for the Glider honors.
“Kurt was one of few people to achieve
three scores at one location. It should be noted
that only two scores per location count
towards an individual’s point totals. Kurt had
five regional scores plus his scores at USIC to
take the win with 271 total points.
“Congratulations to all of the winners!
“Contest directors, now is the time to get
your 2008 event added to the schedule. You
never know what out-of-towner may travel
across country in hopes of picking up a few
more points! Information and applications for
inclusion can be found at www.freeflight.org/
competition/IndoorNationalCup/info.htm.”
Following are the final scores for the 2007
Indoor National Cup.
Glider Points
1. Kurt Krempetz, 271
2. R. Romash, 268
3. W. Gowen, 216
4. J. Buxton, 161
5. B. Miller, 121
6. D. DeLoach, 79
7. T. Reynolds, 73
8. M. Covington, 63
9. E. Berray, 61
10. Ken Krempetz, 59
Rubber Points
1. R. Romash, 281
2. T. Sova, 190
3. W. Gowen, 165
4. J. Richmond, 113
5. L. Loucka, 97
6. W. Van Gorder, 94
7. R. Warmann, 90
8. N. Ray, 70
9. S. Fultz, 69
10. W. Leppard, 67
Record-Setting Three-Views: If you’ve
been following this column, you may know
that for many years I’ve been championing
an effort to make the three-view drawings
submitted with Indoor FF record
applications more readily available to the
membership. We’ve had a few bureaucratic
steps backward along the way, but there is
now an official form with which you can
request copies.
The procedure is still far short of my
vision of a Web site with a catalog of
scanned three-view images, and the cost
($10 for the first plans and $5 for additional
drawings) is a bit steep, but at least they are
accessible. Head to the AMA Web site to
get the document.
Those who are looking for more
economical access to great designs can
check out Jeff Hood’s Indoor News Web
site. It has an online Indoor FF record list
with three-views attached to several of the
entries. The site also features a separate
“Downloads” area with many more plans
and three-views. There’s lots of great info
here, and it’s all free.
If you have set a record, have a niceflying
model, or just want to share your
efforts, consider sending an image to Jeff.
He can post it along with the others. There’s
nothing like a good grassroots effort to cut
through the red tape!
Photo Credits: It seems that the credits for
last column’s photos got lost in the mix, so
I’m sending recognition to Max Zaluska for
those pictures. In addition to being a fine
model-airplane craftsman and pilot, Max has
talent with a camera.
You can check out more of his image
wizardry online. He has many modelairplane
shots from a variety of events, as
well as other interesting subjects.
152 MODEL AVIATION
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