November 2006 91
GREETINGS, micro fans. It does not seem
possible, but another two months have flown
by while I have been puttering around. I have
a variety of topics to share, so hang with me
and enjoy.
If some of you believe that micro RC is a
relatively new field, check out the picture of
the Corben Super Ace. It has a wingspan of
19 inches and weighs 2 ounces. It is
controlled with a single-channel proportional
system and powered with a Cox .010.
This little powerhouse of an engine
would have been way too potent as
delivered so several steps were taken to
reduce the output. A larger propeller was
fitted and a restrictor was placed over the
exhaust ports to maintain a lower rpm.
The significance of all this is that the
year was 1968 and there were several
modelers flying micro RC models by then.
Another photo shows an unusual
project: a micro electric ornithopter that is
adaptable to micro RC. Nathan Chronister
developed this one. We all know it’s
impossible to fly by flapping wings, yet
Nathan has been constructing all kinds of
different flapping-wing models called
ornithopters for more than 15 years.
As Leonardo da Vinci famously observed,
“The bird is a machine that operates according
to mathematical law.” Therefore, we can
duplicate its flapping-wing method of flight.
Nathan Chronister has hatched what may
be the world’s smallest electric-powered
ornithopter. It weighs only 3.8 grams—
roughly half the weight of previous models!
The tiny flying aircraft uses a 4mm-diameter
coreless motor, powered by a 20 mAh Li-Poly
battery.
Construction is of balsa wood and
condenser tissue. The ornithopter was
designed to use either an electronic timer, as
shown, or Plantraco’s HFX 0.3-gram receiver
and a HingeAct actuator to move a rudder.
The timer weighs roughly the same as the
Plantraco RC system. It is a HiLine FF that
was modified to save weight by removing the
control dial. The little model flies until the
timer shuts off, then it glides gently to the
ground.
A special gearbox was developed in
collaboration with Andrew Streett of the
Rochester Institute of Technology (RIT). The
gearbox frame was drawn using SolidWorks
3-D mechanical-design software and then
manufactured from ABS plastic using RIT’s
rapid prototyping equipment. The tiny gears
mesh perfectly because of this precision
manufacturing technique. The gear unit allows
the tiny motor to flap the wings at an
astonishing rate: roughly 10 times each
second!
Andrew and other RIT students went to
Utah in May to compete in the 10th annual
Micro Air Vehicle competition. In that
competition Andrew flew his own ornithopter
using a larger version of the same gearbox.
For more information about flapping-wing
models, visit the Ornithopter Zone Web site at
www.ornithopter.org.
For a change of pace I am going to share a
letter and picture that came in from John
Krouse, 1124 Pipestem Pl., Rockville MD
20854. One of the photos shows John’s latest
model. He wrote:
The amazing ornithopters of Nathan Cronister
Micro-Flying Dave Robelen | aplusfarm@hovac.com
Also included in this column:
• John Krouse’s change-of-pace
ROG
• Microservo review
• Three-view sources
• Micro equipment and supplies
sources
Unusual micro electric-powered ornithopter is adaptable to RC. It is one of a number of
flapping-wing aircraft developed by Nathan Chronister.
This 2-ounce Corben Super Ace micro RC built in 1968 was one
of a number of micro RC models flying at that time.
Bored with hand launching, John Krouse built this original
aircraft as a rise-off-ground model for a fun change.
11sig3.QXD 9/25/06 1:58 PM Page 9192 MODEL AVIATION
The author’s latest project is a miniature version of the Quaker FF model found in a
Frank Zaic Year Book from the 1930s.
This month the author highlights three microservos (L-R): the Falcon, the Gasparin
GD, and the Lightning, formerly sold by Dynamics Unlimited.
“I thought you might be interested in my
indoor ultralight RC model controlled by the
latest Micro Invent Minor receiver, available
from Bob Selman at BSD Micro RC at
www.bsdmicrorc.com or www.airmidi
micros.com. I was becoming bored with hand
launching, so I thought an ROG [rise-offground]
design would be a fun change. Larry
Park makes the carbon-fiber landing gear and
laser-cut plywood wheels available through
www.roomflight.com.
“The wing construction is fairly
conventional: 3/32 square balsa LE, TE, and
ribs, held together with Titebond glue, and
Reynolds Wrap for covering. The
horizontal tail is formed by bending a piece
of 0.3mm carbon-fiber rod into a
semicircular shape, and secured at the tips
with a 1/8-inch-wide strip of stiff 1/32 balsa
bonded with cyanoacrylate. The covering is
5-micron RA Microlite.
“The ‘drive train’ consists of a 6 x 12mm,
4.5-ohm (green) pager motor coupled to
Gasparin 3.2:1 reduction gearbox, spinning a
3.2-inch carbon-fiber propeller by
Microinvent MCF 3222—all powered by a
single 60 mAh Li-Poly cell. The components
are from BSD Micro RC. Lift for the 16-
gram model comes from a 3.75 x 12.5-inch,
single-surface, cambered wing.
“Based on the successful flying
characteristics of (and experience with)
previous models, the throttle and rudder
controls (no elevator/ailerons) seemed
adequate for all but 3-D aerobatic
maneuvers, minus the additional weight.”
Thanks for sharing, John. There is plenty
of original activity in the micro field.
I thought it might be a good idea to review
some of the microservos available to us
that are truly micro in their weights. One of
the pictures shows three that I have had
experience with and can recommend. The
1.6-gram Falcon servo is available from
BSD Micro RC. The unit in the picture is
an earlier model; check the company’s Web
site for the most current one.
The servo in the center is the Gasparin GD,
which is the lightest of the group at 1.3 grams.
It has no cable or plug. It can be found at
the Didel Web site at www.didel.com. The
other servo is the Lightning that was sold
by Dynamics Unlimited.
The Falcon and the Lightning are
slightly more rugged and are furnished
with a cable and JST connector to mate
with current narrow-band receivers.
Another possibility for this group is the
Breeze: a modular unit made by Falcon
that contains two servos and a
microreceiver in one case. It is available
from BSD Micro RC.
It is time to toss out a challenge for more of
you to get involved in scratch building a
micro RC model. Check out the photo that
shows the beginnings of my latest project—a
miniature replica of the Quaker FF model
from the 1930s.
There is a limit to the number of micro
designs currently available, but you can do
something about that! In my case, the Quaker
was enlarged from a small three-view in a
Frank Zaic Year Book from the 1930s. These
books are a treasure trove of designs and can
be purchased from AMA. Go to www.model
aircraft.org and click on the Webstore tab.
There are all kinds of good things there.
Meanwhile, if scale models are your thing,
there is a Web site that compiles a vast
quantity of model plans and three-views. Visit
www.simaviation.com/designresources.htm.
Nearly all the three-views and drawings
you come across will be a different size from
what you want to build. The solution is the
modern copy shop (Kinko’s in my area),
where drawings may be enlarged or reduced to
the desired size.
As for structure, many of my small-scale
models are all balsa—generally 1/32 sheet. If a
full-bodied project seems too much at first,
why not build it as a profile? That has worked
well for others.
There are probably some of you holding
back because of a lack of information or
intimidation by the process. Go ahead and take
the plunge! The materials are certainly cheap
and the models are damage resistant.
Meanwhile, remember to send me a picture of
your new creation.
I want to acknowledge some of the dealers in
micro equipment and supplies that have served
me well through the years. Many of these are
family businesses and the service is excellent.
There is no significance to the order of listing.
An extensive line of equipment, accessories,
and models:
Bob Selman Designs
www.bsdmicrorc.com
A full line of equipment, accessories, and
models:
Sky Hooks and Rigging
http://skyhooks.ca.
Home of the 900 MHz micro equipment, the
Butterfly ARF living-room flyer, and much
more:
Plantraco
www.plantraco.com
Micro RC equipment, accessories, and
models:
BP Hobbies LLC
www.bphobbies.com
An extensive line of supplies, materials, and
some equipment:
Dave Lewis
www.homefly.com
Til next time. MA
11sig3.QXD 9/25/06 2:26 PM Page 92
Edition: Model Aviation - 2006/11
Page Numbers: 91,92
Edition: Model Aviation - 2006/11
Page Numbers: 91,92
November 2006 91
GREETINGS, micro fans. It does not seem
possible, but another two months have flown
by while I have been puttering around. I have
a variety of topics to share, so hang with me
and enjoy.
If some of you believe that micro RC is a
relatively new field, check out the picture of
the Corben Super Ace. It has a wingspan of
19 inches and weighs 2 ounces. It is
controlled with a single-channel proportional
system and powered with a Cox .010.
This little powerhouse of an engine
would have been way too potent as
delivered so several steps were taken to
reduce the output. A larger propeller was
fitted and a restrictor was placed over the
exhaust ports to maintain a lower rpm.
The significance of all this is that the
year was 1968 and there were several
modelers flying micro RC models by then.
Another photo shows an unusual
project: a micro electric ornithopter that is
adaptable to micro RC. Nathan Chronister
developed this one. We all know it’s
impossible to fly by flapping wings, yet
Nathan has been constructing all kinds of
different flapping-wing models called
ornithopters for more than 15 years.
As Leonardo da Vinci famously observed,
“The bird is a machine that operates according
to mathematical law.” Therefore, we can
duplicate its flapping-wing method of flight.
Nathan Chronister has hatched what may
be the world’s smallest electric-powered
ornithopter. It weighs only 3.8 grams—
roughly half the weight of previous models!
The tiny flying aircraft uses a 4mm-diameter
coreless motor, powered by a 20 mAh Li-Poly
battery.
Construction is of balsa wood and
condenser tissue. The ornithopter was
designed to use either an electronic timer, as
shown, or Plantraco’s HFX 0.3-gram receiver
and a HingeAct actuator to move a rudder.
The timer weighs roughly the same as the
Plantraco RC system. It is a HiLine FF that
was modified to save weight by removing the
control dial. The little model flies until the
timer shuts off, then it glides gently to the
ground.
A special gearbox was developed in
collaboration with Andrew Streett of the
Rochester Institute of Technology (RIT). The
gearbox frame was drawn using SolidWorks
3-D mechanical-design software and then
manufactured from ABS plastic using RIT’s
rapid prototyping equipment. The tiny gears
mesh perfectly because of this precision
manufacturing technique. The gear unit allows
the tiny motor to flap the wings at an
astonishing rate: roughly 10 times each
second!
Andrew and other RIT students went to
Utah in May to compete in the 10th annual
Micro Air Vehicle competition. In that
competition Andrew flew his own ornithopter
using a larger version of the same gearbox.
For more information about flapping-wing
models, visit the Ornithopter Zone Web site at
www.ornithopter.org.
For a change of pace I am going to share a
letter and picture that came in from John
Krouse, 1124 Pipestem Pl., Rockville MD
20854. One of the photos shows John’s latest
model. He wrote:
The amazing ornithopters of Nathan Cronister
Micro-Flying Dave Robelen | aplusfarm@hovac.com
Also included in this column:
• John Krouse’s change-of-pace
ROG
• Microservo review
• Three-view sources
• Micro equipment and supplies
sources
Unusual micro electric-powered ornithopter is adaptable to RC. It is one of a number of
flapping-wing aircraft developed by Nathan Chronister.
This 2-ounce Corben Super Ace micro RC built in 1968 was one
of a number of micro RC models flying at that time.
Bored with hand launching, John Krouse built this original
aircraft as a rise-off-ground model for a fun change.
11sig3.QXD 9/25/06 1:58 PM Page 9192 MODEL AVIATION
The author’s latest project is a miniature version of the Quaker FF model found in a
Frank Zaic Year Book from the 1930s.
This month the author highlights three microservos (L-R): the Falcon, the Gasparin
GD, and the Lightning, formerly sold by Dynamics Unlimited.
“I thought you might be interested in my
indoor ultralight RC model controlled by the
latest Micro Invent Minor receiver, available
from Bob Selman at BSD Micro RC at
www.bsdmicrorc.com or www.airmidi
micros.com. I was becoming bored with hand
launching, so I thought an ROG [rise-offground]
design would be a fun change. Larry
Park makes the carbon-fiber landing gear and
laser-cut plywood wheels available through
www.roomflight.com.
“The wing construction is fairly
conventional: 3/32 square balsa LE, TE, and
ribs, held together with Titebond glue, and
Reynolds Wrap for covering. The
horizontal tail is formed by bending a piece
of 0.3mm carbon-fiber rod into a
semicircular shape, and secured at the tips
with a 1/8-inch-wide strip of stiff 1/32 balsa
bonded with cyanoacrylate. The covering is
5-micron RA Microlite.
“The ‘drive train’ consists of a 6 x 12mm,
4.5-ohm (green) pager motor coupled to
Gasparin 3.2:1 reduction gearbox, spinning a
3.2-inch carbon-fiber propeller by
Microinvent MCF 3222—all powered by a
single 60 mAh Li-Poly cell. The components
are from BSD Micro RC. Lift for the 16-
gram model comes from a 3.75 x 12.5-inch,
single-surface, cambered wing.
“Based on the successful flying
characteristics of (and experience with)
previous models, the throttle and rudder
controls (no elevator/ailerons) seemed
adequate for all but 3-D aerobatic
maneuvers, minus the additional weight.”
Thanks for sharing, John. There is plenty
of original activity in the micro field.
I thought it might be a good idea to review
some of the microservos available to us
that are truly micro in their weights. One of
the pictures shows three that I have had
experience with and can recommend. The
1.6-gram Falcon servo is available from
BSD Micro RC. The unit in the picture is
an earlier model; check the company’s Web
site for the most current one.
The servo in the center is the Gasparin GD,
which is the lightest of the group at 1.3 grams.
It has no cable or plug. It can be found at
the Didel Web site at www.didel.com. The
other servo is the Lightning that was sold
by Dynamics Unlimited.
The Falcon and the Lightning are
slightly more rugged and are furnished
with a cable and JST connector to mate
with current narrow-band receivers.
Another possibility for this group is the
Breeze: a modular unit made by Falcon
that contains two servos and a
microreceiver in one case. It is available
from BSD Micro RC.
It is time to toss out a challenge for more of
you to get involved in scratch building a
micro RC model. Check out the photo that
shows the beginnings of my latest project—a
miniature replica of the Quaker FF model
from the 1930s.
There is a limit to the number of micro
designs currently available, but you can do
something about that! In my case, the Quaker
was enlarged from a small three-view in a
Frank Zaic Year Book from the 1930s. These
books are a treasure trove of designs and can
be purchased from AMA. Go to www.model
aircraft.org and click on the Webstore tab.
There are all kinds of good things there.
Meanwhile, if scale models are your thing,
there is a Web site that compiles a vast
quantity of model plans and three-views. Visit
www.simaviation.com/designresources.htm.
Nearly all the three-views and drawings
you come across will be a different size from
what you want to build. The solution is the
modern copy shop (Kinko’s in my area),
where drawings may be enlarged or reduced to
the desired size.
As for structure, many of my small-scale
models are all balsa—generally 1/32 sheet. If a
full-bodied project seems too much at first,
why not build it as a profile? That has worked
well for others.
There are probably some of you holding
back because of a lack of information or
intimidation by the process. Go ahead and take
the plunge! The materials are certainly cheap
and the models are damage resistant.
Meanwhile, remember to send me a picture of
your new creation.
I want to acknowledge some of the dealers in
micro equipment and supplies that have served
me well through the years. Many of these are
family businesses and the service is excellent.
There is no significance to the order of listing.
An extensive line of equipment, accessories,
and models:
Bob Selman Designs
www.bsdmicrorc.com
A full line of equipment, accessories, and
models:
Sky Hooks and Rigging
http://skyhooks.ca.
Home of the 900 MHz micro equipment, the
Butterfly ARF living-room flyer, and much
more:
Plantraco
www.plantraco.com
Micro RC equipment, accessories, and
models:
BP Hobbies LLC
www.bphobbies.com
An extensive line of supplies, materials, and
some equipment:
Dave Lewis
www.homefly.com
Til next time. MA
11sig3.QXD 9/25/06 2:26 PM Page 92