Frequently Asked Questions - 2012/02

84 MODEL AVIATION
PLEASE WRITE IN with your questions.
That is the only way we can keep this
column format going. When referring to
previously published questions and answers
(for follow-ups), always provide the number
as a reference.
References to addresses and websites are
placed in a group, separate from the text, at
the end of this column under “Sources.”
Another feature, “Tips,” will be
provided in addition to frequently
asked questions. These tips will be
numbered in the same sequence as
the questions.
Q540: “I’ve seen
references indicating that
several new RC systems now
include built-in telemetry
devices. These units send
signals from the model
back down to the pilot
holding the RC
transmitter on the
ground. Information such
as onboard battery voltage
can then be made available
to the pilot while the aircraft is
in flight. My RC system is
several years old and does not
have this kind of
capability. Are there
any add-on
telemetry systems
available that would
benefit me?”
A540: I know of
several such
devices, or I should
say, I’ve seen the
advertisements for
them. Some are
available from the
original equipment
manufacturer and
Left: Park Flyer Plastics molded-plastic, dummy
radial engines can add so much realism to a
Scale project for little cost and no effort.
Above left: The receiver portion of the Hobby King
Quanum Telemetry System is attached to a transmitter
antenna and powered with a Li-Ion battery. The pilot
can read the battery cell voltages while the airplane is
in the air.
Noted designer/author Keith Sparks operates Park Flyer Plastics and offers many
Scale items on his website including this semiscale warbird.
Below: Common acetone solvent can help you
apply trim to the iron-on covering on your
model without the need for heat. The author
describes this simple process.
Add-on telemetry systems for on-board batteries
Bob Aberle | baberle@? Frequently Asked Questions optonline.net
Also included in this column:
• Aircraft, scalelike canopies, and
more
• Covering techniques and trim
solvents
• New source for Old-Timer/
Vintage plans
• RC boats and ducted-fan power
02sig3.QXD_00MSTRPG.QXD 12/16/11 1:53 PM Page 84February 2012 85
A closer view of the 1979 Aqui-Duct RC boat shows that it was
constructed from common plastic foam. It was approximately 4-
feet long.
A thinner Bob Aberle, in 1979, launches
the Aqui-Duct RC boat for Nick Ziroli Sr.
The original design needed more rudder
area after which it controlled perfectly.
Bob’s daughter,
Patti, in 1979 (at
age 14) is holding
his Aqui-Duct RC
boat, powered by
an Axiflo ductedfan
system. Bob
suggests revisiting
this design using
an electric ductedfan
unit.
This set of plans was downloaded from a UK website known as
Outerzone. More than 1,500 plans are available and can be
downloaded and copied at a printing facility.
others are truly aftermarket (generic) devices. I saw one such add-on
apparatus demonstrated at my local club field, so let me report on
that particular system.
It is called the Quanum Telemetry System and is offered by
Hobby King. The device includes both a transmitter that goes into
the aircraft and a receiver that you attach to your RC transmitter
(any type or brand). It sells for $49.99 as of October 2011.
The Quanum (that’s the way Hobby King spells it, but I think
someone forgot the “T”) provides real-time voltage, current, mAh,
and temperature display information, as well as a low-voltage
warning alarm. The display and alarm operate from the special
receiver that you mount or attach to your RC transmitter. That
receiver is self-powered by an internal 450 mAh Li-Ion battery,
which you must charge separately from your transmitter.
The large 132 x 64 mm LCD screen is easy to read. The Quanum
Telemetry System will warn you when your battery is approaching
3.2 volts per cell with a variable audio tone. This type of warning
will help eliminate dead-stick landings.
The radio link from the transmitter to the receiver is on 2.4 GHz
DSSS, which claims not to interfere with your primary RC system.
In the photo that I included with this column, the individual cell
voltages appear on the receiver screen. This results when you plug
the onboard telemetry transmitter into the battery pack’s node or
balance connector. This will help determine if any particular cell is
becoming unbalanced while the aircraft is in flight.
02sig3.QXD_00MSTRPG.QXD 12/16/11 1:53 PM Page 85To obtain all the features of this system,
you will need to purchase an optional
current/temperature sensor, which also goes
onboard your aircraft. That sensor costs
$19.79.
I’ve flown this system and I’m impressed
with the way it works. One thing I really
liked is that I could use half my battery
charge and land. Without recharging, I could
make a second flight on the remaining
charge, before the warning alarm sounded.
Would that feature interest you?
Q541: AMA member Jim Noffze wrote in
and asked where he might find a source for
scalelike canopies. His interest is in .40- to
.61-size warbirds. These fighters require a
decent canopy to look authentic, rather than
being simulated with paint. His modeling
friends indicated that he should make a plug
and vacuum-form the canopies, but that
takes craftsmanship and time to do the job
correctly. Where can Jim find a source to
purchase these canopies?
A541: I did some searching and networked
with some of my Scale modeling friends.
What I came up with surprised me.
There is an excellent source for scalelike
canopies; they can be purchased from a
company known as Park Flyer Plastics. The
owner of this company is a well-known
modeler by the name of Keith Sparks.
You have probably seen many of Keith’s
designs as construction articles in the
various hobby publications. I’ve listed
Keith’s website in the “Sources” section.
What surprised me were various scalelike
items that Keith also sells.
I found an entire series of dummy,
plastic-molded radial engines. He has
painted pilot heads or busts, molded plastic
wheel pants, and a selection of 23 model kits
with foam and balsa construction. Visit
Keith’s site and familiarize yourself with his
product line.
Tom Hunt published an interesting howto
article on scalelike canopies in the August
2008 Fly RC magazine. The subject of this
article was how to dress up your scalelike
canopies. In this article, Tom shows how to
add detail to a basic vacuum-formed canopy
for added realism. I’ve included the website
information for that article in the “Sources”
section.
Q542: “I seem to have a heck of a time
adding trim to my iron-on covered models.
No matter what I do, I get air bubbles
between the two layers of covering. I heard
that you can use a solvent to add trim pieces
without the need for heat. What is that all
about?”
A542: Many iron-on covering suppliers
offer solvents that let you apply trim pieces
of covering material on top of the surface
that you have already covered, without the
need for heat. These solvents come under
many different names, but Jim Minadeo of
BP Hobbies told me that the basic trim
solvent you need is plain old acetone, which
you can find at almost any paint or hardware
store.
As soon as I heard this suggestion, I
made up a test piece to try it. I covered a
piece of balsa sheet using my heat iron.
Then I cut out trim strips from a different
colored covering material. I wiped the
acetone onto the covered surface and
applied the trim strip on top of it. I gave the
trim and the covering one more wipe of
acetone and let it set for a while. To be sure
that the trim stayed in place, I applied some
heat to the end joints.
The result was a smooth surface free of
air bubbles. Best of all, the trim ended up
exactly where I wanted it.
T543: My thanks to Canadian modeler and
prolific designer, Chris Moes, for sharing
with me a wonderful, free plans service. The
service is known as Outerzone and it
originates in the United Kingdom. The
website is provided in the “Sources” listing.
The site lists more than 1,500 model
aircraft plans. You can download any one
you like into a PDF file and take it to a
printing service such as Staples or FedEx
Kinko’s and have your plans run off at any
size you desire.
There are many types of aircraft,
including Vintage RC, Old-Timers, FF,
Scale, and rubber-powered models. I found
it thrilling to read through the list. Do
yourself a favor and check out this site. My thanks to you, Chris!Q544: “Bob, you were kind enough to send
me your listing of all your published designs
that you referred to in your August 2011 MA
column (Q510). As I was reading through
your list, I noted a single RC boat. Did I
read that correctly? What was that all
about?”
A544: In the late 1970s, longtime modeler
Bob Kress developed a ducted-fan system
using high-powered, glow-fueled engines,
along with specially designed multibladed
fans. The fans ran inside a duct or tube.
Bob named the system the Axiflo and
created a company to market it, known for
many years as Kress Jets, Inc. Bob was an
MIT graduate, a Grumman vice president,
and one of the principal designers of the
Grumman F-14 Tomcat.
At the time, Bob asked me to try out one
of the prototype Axiflo ducted fans using a
K&B .40 Schnuerle-ported racing engine. I
didn’t have time to build an airplane for this
system, but I did come up with an
alternative.
I fashioned a foam surfboard available
from Walmart into a boat that I named the
Aqui-Duct. It turned out to be more
successful than any of us expected. I placed
the Axiflo on top of the foam surfboard
toward the rear. Behind the duct I arranged a
rudder and elevator using RC control.
As I remember, the elevator wasn’t
effective (it wasn’t an aircraft), and the
rudder needed more area, but once I
enlarged it with the ducted fan passing
wind-tunnel-velocity air on the rudder,
steering control was very effective.
Nick Ziroli Sr. and I ran the Aqui-Duct at
the big Lake Ronkonkoma, on Long Island.
It moved fast and was fun to operate.
The thought now comes to mind that this
boat concept might work today with electric
ducted-fan units. There are many now
available. I’m sure these foam surfboards
are still available as well, but you could cut
one out of 1-, 2-, or 3-inch foam slabs.
The original plans for the Aqui-Duct are
still available from Carstens Publications, as
Plan No. CB-11. The construction article for
this boat appeared in the January 1979
Flying Models. I hope my readers won’t
mind this one departure from aircraft into
the marine world. MA