RC Airplanes | Gliders | Helicopters
CORSAIR
pg 94
JUNE 2014
EXCLUSIVE:We visit
For A Look at the NEW
S1000 OCTOCOPTER Go inside TT with us to see how they make some of the best RC products in the World.
SPECIAL REPORT RC is really taking off in China! Get an inside look at pilots that fly in Beijing’s Olympic Village.
SF shows you how this factory makes airplanes you’ll want to fly.
USA & CANADA $6.49
RC-SF.COM
TABLE OF CONTENTS DEPARTMENTS
10 LEADING EDGE 12 HOT PRODUCTS 102 AD INDEX 103 MYSTERY PLANE
LEARN FROM OUR EXPERT HOW TO MAKE GEAR DOORS THAT CLOSE FITTINGLY.
PG 62
FEATURE
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BEIJING RC
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THUNDER TIGER
SEE WHY WE THINK OUR NEXT WORLD CHAMP WILL LIKELY COME FROM CHINA. By Wil Byers
WE SHOW YOU HOW THESE PEOPLE MAKE HIGH-QUALITY RC PRODUCTS. By Wil Byers
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PILOT RC
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DJI VISIT
GO INSIDE THIS FACTORY WITH US TO SEE HOW THEY MAKE AIRPLANES. By Wil Byers
LOOK AT HOW DJI IS “DEFINING THE FUTURE OF POSSIBLE.” By Wil Byers
BEIJING RC PILOTS ARE STARTING TO PUSH THE OUTSIDE OF THE ENVELOPE.
PG 42 DJI CREATES AN INNOVATIVE WORK CULTURE FOR SUCCESS!
HOW TO
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RC SPORT FLYER . JUNE 2014
FUNCTIONAL GEAR DOORS THIS ARTICLE TEACHES YOU THE TRICKS OF MAKING DOORS THAT WORK. By Tom Wolf
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AEROBATICS PART 15 GET OPTIMAL PERFORMANCE BY INSTALLING EXHAUSTS RIGHT. By Daniel Holman
twitter.com/rcsportflyer
JUNE 2014
BUILD
COLUMN
50 HALL’S SPRINGFIELD
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BULLDOG II
LEARN FROM A PRO THE BUILDING STEPS OF HOW TO MAKE A GULL WING. By Rob Caso
COVERING PREP
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SEE WHY GETTING IT READY IS A BIG PART OF GETTING IT DONE RIGHT. By Jeff Troy
E-POWER 9 THE GREAT MOTOR/ GENERATOR EMF DICHOTOMY IS EXPLAINED BY ANDREW. By Andrew Gibbs
3-VIEW
REVIEWS
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PIPER PA-25 PAWNEE AN AIRPLANE PURPOSE-BUILT FOR HEAVY LIFTING. By Hans-Jürgen Fischer
CARBON-Z CUB BNF BASIC SEE WHY THIS AIRPLANE IS FUN TO TAKE BACKCOUNTRY BUSH FLYING. By Wil Byers
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MULTIROTOR INVASION TAMMIE’S HOBBY HAS THEM IN STOCK, AND IT’S BEEN PROFITABLE FOR THEM. By Lucidity
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HITEC RCD F4U CORSAIR THIS SCALE AIRPLANE IS INEXPENSIVE, EASY TO BUILD, AND MADE FOR PILOTS. By Staff
PG 72 PIPER PA-25 PAWNEE 3-VIEW AN AIRPLANE BUILT FOR HEAVY LIFTING
PG 36
INSIDE PILOT-RC, RC-SF SHOWS YOU HOW LARGE-SCALE AIRPLANES GET BUILT IN CHINA. facebook.com/rcsportflyer
WE TAKE YOU ON A TOUR OF THE THUNDER TIGER FACTORY IN YU YAO.
PG 30 RC-SF.COM
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HOT PRODUCTS DJI S1000 SPREADS ITS WINGS
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ith the release of the DJI S1000 a milestone in aerial photography and cinematography has been reached. The new S1000, combined with a flight controller like the A2, weighs only four kilograms, with a maximum takeoff weight of about eleven kilograms, which makes it a very stable, heavy-lift camera platform. The frame arms and the retractable landing gear are made of carbon fiber to ensure lightweight and high structural stability. The eight frame arms are foldable for easy transportation and storage. The high-performance folding propellers can tuck away too. To fly the S1000, you simply lift the frame arms, lock them in place, and power the eight-motor system. The Zenmuse Z15-5D camera gimbal offers advanced stabilization for smooth footage capture, with precision tilt and position control from a remote ground station. There is also full HD video downlink compatibility via the new LightBridge, giving the operator the ability to see in high definition what the camera sees. The gimbal mounts low on the frame on a specially designed bracket. When combined with the included retractable
landing gear, it offers a clear, wide shooting angle. Both the gimbal and battery system mount to a common bracket, with dampers placed between the bracket and the frame. This significantly reduces high-frequency vibrations and video capture is clearer and sharper. The battery tray’s position also makes it convenient for mounting and dismounting too. Features • Spark-proof power plug • Low-gimbal mounting position • Retractable landing gear • Zenmuse Z15 gimbal • New damping design
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Innovative frame arm design 4 Kg weight Built-in 40-amp ESC at motors High-strength custom propellers Foldable airframe Carbon frames Five-minute setup time
Price $6350.99
Distributor ATLANTA HOBBY 6110 Parkway North Drive Cumming, GA 30040 Phone: 678-513-4450 atlantahobby.com
Distributor
SOARING USA XPLORER II F5J
SOARING USA 827 N Glendora Ave Covina, CA 91724 Phone: 626-967-6660 soaringusa.com
T
he New Xplorer II F5J has been specifically designed for F5J, ALES type electric-powered glider competitions. It has the same wing design and profile as the two-time F3J World Championship winning Xplorer. The new F5J wing employs state-of-the-art layup techniques, combined with even lighter materials for an incredibly lightweight F5J model. A new fuselage design has further reduced the glider’s drag and weight. The Xplorer II F5J sports a 3.8-m wingspan that has proven to be the most effective and best overall size in most flight conditions. The empty airframe with all parts and hardware weighs approximately 1130 grams. The all
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Specifications Wingspan Wing Area Length Weight Weight
149 in. (3.8 m) 1236 in.2 (79.7 dm2) 64 in. (1.63 m) 39 oz empty (1130 g) AUW 57 oz (1625 g)
up flying weight starts from an incredible 1625 g, which is dependent on radio gear and motor system. Soaring USA includes a complete hardware package. Price
$1899.95 (Xplorer II F5J) twitter.com/rcsportflyer
BLADE 200 SR X BNF
C
heck it out! Now, advancing from an intermediate helicopter to an advanced, flybarless machine is almost seamless with the 200 SR X. The Blade® 200 SR X is the first fixed-pitch helicopter to employ SAFE™ Technology, which means you get an unparalleled flybarless experience. SAFE technology helps facilitate the learning process with beginner, intermediate and experienced flight mode options. Each flight mode utilizes varying amounts of bank limiting and advanced
stability characteristics for pilot assists. Additionally, SAFE technology enables a panic button that can automatically return the 200 SR X to steady flight with the push of a button. This durable helicopter arrangement is complimented by brushless main and tail rotor motors. The kit’s included 3S 800mAh 30C LiPo flight battery and 3-cell LiPo AC-powered balancing charger give long flight times and make charging easy. Importantly, the 200 SR X BNF comes ready to bind with your favorite 6-channel extended range 2.4-GHz DSM® enabled Spektrum™ transmitter. Features • Engineered with SAFE™ technology
• Panic button recovery • Beginner mode—limited flight envelope with self-leveling and a low bank angle limit • Intermediate mode—self-leveling and a high bank angle limit • Experienced mode—full stick control with no bank angle limit • Brushless main and tail motor • Stainless steel main shaft • Flight times up to 10 minutes • Flight battery and charger included Price
$219.99 (BLH2080)
Specifications Type Fixed pitch flybarless electric helicopter Main rotor 16.1 in. (410 mm) diameter Rotor blade Length 7.3 in. (185 mm) Tail rotor diameter 2.4 in. (62 mm) Length 14.8 in. (375 mm) Weight 8.82 oz (250 g) Motor 3900 Kv brushless Battery 3S 800-mAh (not included) Kit/ARF/RTF BNF
Distributor HORIZON HOBBY 4105 Fieldstone Road Champaign, IL 61822 Phone: 217-352-1913 horizonhobby.com
JETI CENTRAL BOX UPDATE
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Distributor Esprit Model 1240 Clearmont St NE, Unit 12 Palm Bay, FL 32905 Phone: 321-729-4287 espritmodel.com facebook.com/rcsportflyer
eti’s update provides new options for digital inputs and outputs to their Central Box 200. For example, you can control your model’s LED lights using the Central Box. Also, the Central Box can function as an EX Bus expander so you can join several Central Boxes together for signal distribution and control redundancy in any model. The 1.20 firmware version adds a digital interface function to the existing settings for the output pins. Individual Central Box 200 outputs can now be configured in three modes: classical servo output, digital output or digital input. In the digital output mode, only the logical level 1 or 0 is generated on the port configured this way. The value of this output is reflecting the assigned output channel and its level. If the servo
position of the specified receiver channel is lower than 0%; i.e., 1.5 ms, the output is set to permanent log 0 (0 V). If the servo position is higher than 0%, log. 1 (3.3 V) will be generated on the pin. In the digital output mode, no control servo pulses are generated for that particular pin. The Central Box with the new firmware can also function as an EX Bus Expander. This function can be activated on the Ext1, Ext2 and Ext3 outputs and this will function even if the Central Box is controlled by the PPM signal (Rx1 and Rx2 input). The Central Box transforms the servo positions from the PPM signal to the EX Bus. The Central Box can detect any sensor that can communicate in EX Bus mode and starts the communication with the sensor automatically using EX Bus protocol. Price $Free
RC-SF.COM
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BEIJING RC OUR NEXT WORLD CHAMPION WILL LIKELY COME FROM CHINA BY Wil Byers
BEI JING
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y first trip to China was in 2001. At that time, I attended the Beijing Model Fair, at the invitation of Mr. Huang. Mr. Huang was the representative of the Aero Sports Federation of China (ASFC), which was established in 1964. The Beijing Model Fair was where it was “happening” in terms of seeing the aircraft that were new or being offered to the RC industry. I was fortunate in that after the Fair Mr. Huang hosted me to visit other factories near Shanghai and in the south of China near Shenzhen and Zhuhai. China has, over the last three decades, become the world’s manufacturing center for everything from water bottles to automobiles, and even full-scale airplanes. China RC pilots fly their aircraft in the former Olympic Village, which is now home to the stunning Beijing Olympic Park Observation Tower.
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twitter.com/rcsportflyer
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Notice how when this modeler readies his Sbach e-powered model there is a father and son looking on. It was this way for almost all the pilots and their aircraft.
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Kong Guan hovers his electricpowered Sbach as a testament to his skill at flying model airplanes. He was a very focused pilot and it showed in his flying.
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is, without question, now the leading manufacture of model aircraft — building airplanes, helicopters, multirotors and even some gliders. So when you receive nearly any model airplane box these days, it is signatured with the words MADE IN CHINA. It should not be surprising, then, that the RC pilot community in China is growing, and growing rapidly. This is especially so in light of the fact that China’s middle class society is emmerging at an accelerating rate, with its rolls expected to exceed some 650 million people by 2020, while Ernst and Young predicts China’s middle class will exceed one billion by 2030. facebook.com/rcsportflyer
This past March I had the opportunity to visit China for business. I arrived in Beijing by way of Delta airlines and a 14-hour flight. After a day to resolve some of my jet lag, I was given the opportunity to visit the Olympic Village to see the changes made there since China’s hosting of the 2008 Games. The Village has not changed all that much, with the exception of the new Beijing Olympic Park Observation Tower, which is amazing in that it towers over the park at a height of 797 feet (243 meters). It has five observation areas, which also include restaurants, bars, and gift shops. It will be a hallmark of Beijing for years to come.
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Kong was flying a Futaba radio that had a 2.4-GHz adapter module in it. Look closely, you can see the Olympic Village’s Bird Nest in the background.
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This flat foamy is a copy of a Chinese J-10 fighter jet. In this case, it is using a pusher propeller system, a LiPo pack and control is by Futaba.
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As you can see, the J-10 gets a hand launch and off it went on another mission to combat any intruder of Chinese airspace.
What has changed is the number of RC pilots in and around the Beijing area. As I was told, there are now at least five RC airfields in the Beijing area, and with a population of 26 million and growing, it is expected that more RC airfields will be made available to pilots in the not too distant future. So it was that in the shadow of the Observation Tower that I met RC-SF.COM
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PILOT RC
FROM START TO FINISH, THIS FACTORY MAKES AIRPLANES YOU’LL WANT TO FLY! BY Wil Byers
P ZHONG SHAN
ilot-RC is a relatively new company. It opened for operation in March of 2008. The impetus for the company was Tony Tan, with the help of an RC friend. Tony is an RC pilot from the south of China who told me he has a true passion for flying giant-scale RC airplanes. Tony started Pilot-RC with his friend and a very experienced giant-scale builder, Elvis Zhou. As Tony told me, he was an electrical engineer before starting Pilot-RC. In nearly all of his spare time he was building and flying giant-scale, gas-powered airplanes.
Tony Tan is the owner of Pilot-RC. He is greeting me at the door of his 28,000 square foot factory in Zhongshan city, Guangdong Province, China.
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Then he met Elvis in 2005. They became RC friends, enjoying the thrills of flying giant-scale, aerobatic airplanes. So during a flying session on January 1, 2008, Tony and Elvis discussed the idea of opening a factory to build high-quality RC airplanes. They wanted to create a company that would be entirely based in China, rather than just part of the company. It was not long after the discussion that Tony and Elvis put together a business plan to start a company to build model airplanes. So it was that in Zhongshan City, Guangdong Province, China the
Tony shows me the custom-made 55%-scale Yak-54 he is making for a customer in Spain. He told me it will be shipped to the customer by DHL air freight. twitter.com/rcsportflyer
factory was opened, with a meager beginning, but one that was focused on making high-quality, giant-scale, gas-powered RC airplanes. As I learned, the company started small in a shop that was only 10,760 square feet. It had only four workers besides Tony and Elvis. It has since grown and now occupies a building that is 28,000+ square feet and employs 80 workers. The factory is also located in a small (by Chinese standards) but very clean city which is very near Hong Kong. This location aids Pilot-RC in exporting the models
to countries all over the world. What I found inside Pilot-RC is a factory that is clean and well organized in terms of production. Its staff seems 100-percent-plus dedicated to making high-quality, superb-flying airplanes. Moreover, I found that Tony is dedicated to his workers. As an example, Tony designed and built a huge air conditioning system to remove the balsa dust from the air so that his employees have a healthy working environment. The work spaces were also well kept, as were the offices.
Tony explained that he is dedicated to creating a work environment where his employees are appreciated for their skills. DESIGN Pilot-RC is extremely well organized from design to packaging. I was impressed! The product line for Pilot-RC airplanes is designed by Elvis. However, Pilot-RC uses customer feedback as a method for evolving product design and quality — doing so since the company’s beginning.
Laser Cutting
This is one of three large laser cutters that Pilot-RC uses to cut both plywood and balsa parts. Notice that even this laser cutter is relatively clean, even though it is in constant use.
As you can see, not much plywood is wasted in the laser cutting operation, with many parts being cut from each piece of wood. This is engineering that takes time and money to do.
Prefabrication All parts of the factory are kept clean and well organized so there is a worker-friendly environment for the employees. This is a prefabrication area.
Here is the beginnings of a left wing for a Yak, with the wing tube glued in position, the spar in place and some of the ribs located.
This worker is building wing spars for a Yak 54. The spars will then be located in a jig, ribs added, wing tube installed, and then sheeting applied. facebook.com/rcsportflyer
RC-SF.COM
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THUNDER TIGER
AN INSIDE LOOK AT HOW GREAT RC PRODUCTS ARE MADE BY Wil Byers
YU YAO
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u Yao, China, is a city to the south of Shanghai by about 100 miles. It is a small city by Chinese standards, with a population of approximately one million. It is also home to the three-year-old Thunder Tiger (TT) factory. Thunder Tiger is a corporation owned by Aling Lai. Aling has been in the model airplane and hobby business for many years. So, when I was offered an opportunity to visit his factory to see how Thunder Tiger airplanes, boats, and cars are made, I was enthused about the opportunity.
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Thunder Tiger’s factory is located to the south of Yuyao, set at the base of lush, green, rolling hills. It is surrounded by other factories. Just to the west of the main building about 100 meters is a dormitory area, which also houses a large dining hall for the more than 400 employees. There is a courtyard area that I was told is sometimes used for helicopter testing or for their RC cars. What is impressive is to go inside the factory and see how this sevenstory operation is organized and run, making some of the best RC products you can buy anywhere. It begins with a huge office area. The office area is adjoined by the design center, which also does duty as the order and export area. All areas are clean, well lit, and well stocked with computers. The employees were sporting Thunder Tiger jackets, which gave the company a cohesive, corporate family feel to me as an outsider. Moreover, I was greeted warmly by the employees, from management to production staff. Mr. Terry Hsu acted as my host. He has been with Thunder Tiger for more than 20 years, and is an expert in nearly every aspect of plant operation and production. As such, he showed me the factory’s inner workings. twitter.com/rcsportflyer
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Yu Yao is a small city by Chinese standards, but it is home to many production factories. It has the feel of a traditional Chinese city.
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Jimmy Lai is Thunder Tiger’s development manager. He has been with the company for many years and is responsible for product evolution and testing.
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Terry Hsu is the production manager at Thunder Tiger, Yu Yao China. He is showing me one of the plastic boat hulls blown by their custom-made machine.
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There are many machine bays in the Thunder Tiger factory. Parts progress from machine to machine in the build. Notice how clean this area is kept.
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Here a technician is using software that renders a part in three dimensions. This 3D image will then be used by the CNC machine to cut the part to form.
PEOPLE As with any large, successful corporation, Thunder Tiger is run by dedicated staff throughout. I felt like I was looking at a well-oiled machine from design, to packaging, and to distribution. It is truly difficult to put it into words, but seeing this factory in action detailed the who, what, where, when, and how of this factory. Terry underscored for me how Thunder Tiger is constantly changing its product line to meet the needs and wants of the consumers. He also explained how there are literally hundreds of machining steps just in the process of building one kind of car engine. This is obviously the case with many other products as well. On the machine tool floor I witnessed the employees completely and totally focused on their part of the operation. As you can see from the photos that accompany this article, Thunder Tiger has invested heavily in many machine tools, including CNC cutters, water jet machines, and CAD systems. You truly had to see the scope of this operation to understand just how much time, money and man hours go into each product made in this large factory. As Terry showed me, each part facebook.com/rcsportflyer
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typically moves through multiple steps, going from one machine to the next. The workers understand the process intimately, so the quality control is exceptional. From the tool making to the CNC cutting, each part is made to the highest standards. I was particularly impressed with how the steel molds are made
At this stage, the machinist is readying his machine to cut a part. He is checking coordinates before running the machine. The cutting is done inside the machines’ enclosure to keep the operator safe.
for the RC helicopter blades. Also, the custom-made blow-molding machine for making one-piece plastic hulls for RC boats was amazing, with it running from one floor to the next. Impressively, the employees know these machines inside out and backwards, and how to get optimum performance from RC-SF.COM
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DJI VISIT
THE INDUSTRY LEADER DEFINES THE FUTURE OF POSSIBLE BY Wil Byers
SHEN ZHEN 42
RC SPORT FLYER . JUNE 2014
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D
uring the Shanghai Model Fair in 2009, I met Mr. Frank Wang. Mr. Wang, 34, is known as the Chief Executive Officer and Technology Officer of DJI, now an international company with offices the world over. At the time of that first meeting, Frank was busy demonstrating the capabilities of what he said was an innovative quadcopter —capable of flying autonomously. I found him to be a very gregarious guy and filled with enthusiasm for his new machine. While I was impressed with its capabilities (he let me hover it in the convention hall ), I did not see it as revolutionary in terms of aviation and the way we now have the ability to look at and interact with our environment and society using multirotors/drones. Well, hindsight is at least 20/20 at a minimum. So, with the literal skyrocketing of multirotors machines since that meeting in 2009, I’ve wanted to visit the DJI factory and headquarters to see what makes a company like DJI so outstandingly successful.
Therefore, during my trip to China in March, I made it a point to go to Shenzhen — DJI’s headquarters city — and call on DJI to see how its operation is run. Unfortunately, I was not able to visit the DJI production facility, but I was able to visit their offices in the Hong Kong University of Science and Technology (DJI has since moved). What I found was an energetic, millennial (Generation X) staff that was a reflection of their CEO’s vision. It was like walking into the future! Everyone was friendly and cordial,
excited to show us around the offices — even though they were in the process of moving. I even caught a glimpse of Mr. Wang as he hurried to a meeting with DJI’s staff. BEGINNINGS DJI started out of Frank Wang’s love for flying RC helicopters. He grew up in the city of Hangzhou, China, where he learned early on that crashing an RC helicopter could take him months to repair and require no small amount of money for a young man living in China. Nevertheless,
DJI’s new Phantom 2 Vision is the perfect match for their new 3-axis control camera gimbal and an FPV system. facebook.com/rcsportflyer
RC-SF.COM
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BUILD
HALL’S SPRINGFIELD “BULLDOG” PART II “A GOOD SCALE MODEL NEVER LOOKS TO BE AS MUCH WORK AS IT ACTUALLY WAS” BY Robert J. Caso
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y initial article on the Bulldog focused on how the model came to be, the overall design concept, and some specifics on the fuselage, since this is where all the action takes place. In this installment, I will delve into the design for the fancy gull wing, the removable outer panels, and the scale, sprung landing gear, which was personally responsible for many
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late nights. I will also detail how I finished the model, since this took longer than actually building it. THE GULL On a more conventional model — even one having a two or three piece wing — there is usually a center section either in the form of a fuselage or an actual wing center section that forms a contiguous
line and which aids in the alignment of the outer panels. Not so with the Bulldog; the wings are two discreet members that nevertheless must act as one. So, the primary design challenge here was to have mirror images of the gull, installed identically, on each side of the fuselage. To achieve this, each gull’s fore and aft spars key into slots residing in a pair of strategically twitter.com/rcsportflyer
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Tabs on the root of gull spars mate with boxed-out slots in the fuselage bulkheads to provide a positive location on the fuselage.
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One-sixteenth-inch skin has been applied to the gull after holes were made in the fuselage for the aileron lead routing.
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Here the model has been trammeled level and the wings test fitted to establish the proper dihedral and wing incidence.
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The wing mounting tabs have been installed, the LE and sheeting completed, and filler has been applied for the filleting.
placed fuselage formers — the slots themselves hiding just beneath the skinned fuselage. I boxed the slots out underneath with some sheeting so the tabs on the gull spars would slide into them positively, once the skin was slotted to reveal the openings. This gave me a consistent fore/aft location and proper spacing between the spars. The gull’s ribs, once positioned on the spars, also eliminated any twist and caused each assembly to act as a unit. Okay, two axes taken care of, the game now was to make sure that each side would locate the wing root at the same level and with no wing droop or too much dihedral. The long tabs on the spars helped immensely with this, but there still was enough play at the gull’s root to cause a problem. I had previously made a bench stand for the fuselage that bolted onto the firewall location facebook.com/rcsportflyer
and I had designed this to hold the fuselage level when placed on a flat surface. With the fuselage thusly trammeled, I simply measured from the table up to the next to last gull rib, compared these measurements to my CAD drawing, and then tacked in the gull to the fuselage. I left the very last rib loose on the gull to aid in positioning the wing, which came next. REMOVABLE WINGS Removable wings on a 51-in.wingspan model are really not completely necessary and, as it is, I rarely take them off. Nevertheless, such a feature does have its conveniences here for servo wire routing, and it aids in the ability to set the proper dihedral during construction. Note that this feature is peculiar to the larger model and therefore required a considerable
amount of “clean sheet” design effort. The outer panels are quite conventional and offered few challenges to build. Having a “D” box design with two hard balsa secondary spars however, make them quite sturdy. Purists will note I did not pursue a completely scale layout here, opting instead for simplicity as the prototype had what looks like a million ribs in each panel. The mounts for each wing consist of a slender tab of eighth-inch hard plywood on each gull that slides into an internal box in the wing, through which a 4-40 screw is threaded up into a captive blind nut in the wing root, thus securing it. As I constantly recommend, it pays to look at how a particular subject’s wing is supported, and where — in this case as with many others, there is more wing area outboard of the functional “V”struts RC-SF.COM
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BUILD
PREP FOR COVERING
GETTING IT READY IS A BIG PART OF GETTING IT RIGHT.
M
y previous two Super Sportster 60 installments explained how I fiberglassed the center section, aligned and mounted the wing, stabilizer, and vertical fin, and added the fairing blocks under the wing. It looked as if the model might be ready for covering, but a few items still remained on the do-list. These happen now. Mounting an RC switch isn’t an issue, although two items are essential to do it correctly. First, the switch must be mounted on the side
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of the fuselage opposite the engine exhaust to prevent its electrical contacts from fouling. The other is locating a usable wall thickness. The Enya 60’s exhaust port is on its right, so I chose an area of the left fuselage side that was inside one of the plywood doubler’s lightening cutouts. I used the point of an awl to poke through the fuselage in the proper position. Then I traced the switch plate’s mounting holes and slide cutout onto the fuselage side. A 3/32-in. drill bored the mounting holes, and I cut the slide opening
I used an awl to puncture-mark an area between the doublers where the RC switch could be mounted. Always mount the switch on the opposite side of the engine exhaust. RC SPORT FLYER . JUNE 2014
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BY Jeff Troy
with a No. 11 blade. I chose four Hobbico CS-60 standard servos for my airplane, and like all but the smallest servos, rubber grommets and metal eyelets must be installed in their mounting tabs. The rubber usually goes in without a fight, but my chubby fingers and the tight fit make installing the eyelets a major pain, occasionally resulting in bruised fingers and broken nails. My solution was to design an eyelet mounting tool. The tool is a simple woodenhandle screwdriver with the tip
Use the switch plate to trace the cutline for the switch onto the fuselage side. Use the awl or a pencil to mark the fuselage for the mounting screws. twitter.com/rcsportflyer
This was the Super Sportster framework at the close of the last installment. It will be ready to receive its MonoKote covering after just a few more simple procedures.
chopped off, and the last inch or so of the shank turned down. The shank was drilled to accept a hard welding rod, which was shaped to a dull point at the tip. The rod is long and thin enough for four metal eyelets to slip over it, and the turned portion of the shank lets the tool access tight quarters while acting as a stop for the eyelets. The design works flawlessly. I load four eyelets flange-down over the tip, apply a drop of light oil on each eyelet, then I use the tool to push the eyelets, one piece at a time, into the rubber grommets. Finish one servo, load four more eyelets, and repeat for the next servo. The images tell the whole story, and a nearby machine shop could probably make one for you without breaking the bank. The aileron servo mounts require attention because of the wing’s dihedral. Gluing the plywood plates
directly to the wing would leave a potentially troublesome gap under the center of each plate. I circumvent this by cutting two balsa scraps to the outline of the plywood plates, then sawing them partially through at the center so they can bend upward. I use 5-minute epoxy to glue the plates at the ends of the servo opening, pressing down at the center to ensure positive contact with the wing. After the epoxy cures, use the bar sander to sand the balsa pieces flat. Then epoxy the ply plates over them. Now you have two flat mounts with no nasty gap underneath. Use a round file or Perma-Grit tool to cut a notch for the servo lead, then drop in the servo, mark the screw holes, remove the servo, drill the holes, and thread a mounting screw into each hole. Remove the screws and harden the threads in each hole with a drop or two of thin CA.
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This is a tool I designed to make quick work of installing eyelets into servo grommets. My friend and master metal worker Randal Sordelet fabricated the tool from my drawings.
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Here, four brass eyelets are stacked on the tip of the tool, and a drop of lightweight oil is being applied to each eyelet. The oil helps to smooth installation.
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One at a time, use the tool to press the eyelets into the grommets. They slip right in, and you won’t suffer damaged fingers and nails to get them there.
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Two pieces of scrap balsa were cut to fit between the wing panels and the two plywood aileron servo mounts. Score and bend the scraps to match the wing’s dihedral.
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Photo by Greg Wolf
HOW TO
FUNCTIONAL GEAR DOORS MAKING DOORS THAT OPEN AND CLOSE FITTINGLY Photo by Greg Wolf
BY Tom Wolf
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etractable landing gear adds significant complexity to aircraft setup and often impacts aircraft reliability. Scale modelers almost always also have to deal with landing gear doors in conjunction with an airplane’s retractable landing gear. Those who are lucky enough to be modeling an airplane with gear doors that are attached to the landing gear legs have a relatively easy time of making them work properly. However, it is more common to be faced with functional landing gear doors that are hinged and operated separately from the landing gear. Such doors increase the complexity of the gear’s installation and are the potential source of other problems such as doors that stay open during flight, or doors that become fouled with the landing gear during landing gear retraction. A common method for twitter.com/rcsportflyer
controlling and operating the landing gear doors is the use of a sequencing controller and separate landing gear and gear door actuators (either pneumatic or electro-mechanical). The sequencer controls the order and timing of gear’s retraction and door operation. This approach, however, adds parts, weight and system complexity. For my 1/5-scale DeHavilland Mosquito, I chose to go down a somewhat simpler path, one that is a throw-back to what might be considered old-school, but one I have found is not very difficult to implement and has proven to be very reliable once properly adjusted. The full-scale Mosquito’s landing gear doors are simply pushed open by the landing gear during gear extension and the doors are pulled closed by a pair of cables that are attached to the landing gear legs and run through a series of pulleys, ultimately being attached to the gear doors. For my model, I use a similar approach, which is shown schematically in the accompanying diagram. Features of this approach are as follows: • The gear doors are spring-loaded to open to a fixed position that is adjustable to achieve the proper door-open position for a scale appearance. • Door closure is achieved by a pull-string and an inline extension spring that is connected between the gear leg and the door. Adjustment of the
LANDING GEAR LEG
LANDING GEAR DOOR
EXTENSION SPRING DACRON LINE BALL LINK GEAR MOUNTING BLOCK
COMPRESSION SPRING MOUNTING BRACKET (WITH CLEARANCE HOLE FOR DOOR ROD)
WHEEL COLLAR EXTENSION STOP
pull-string is not critical because the spring allows for a wide range of acceptable operation without over-stressing the system. • The gear doors are always held tightly against their door stops when the gear is retracted because the in-line spring provides a positive closing force against the door stops. • The in-line spring makes it possible to manually open each gear door without extending the
The forward door stop is a 1/32-in. plywood strip that is bonded to the inside surface of the nacelle just behind the carburetor scoop, as shown here. facebook.com/rcsportflyer
This diagram shows the basic layout of the gear door operating system for my DH Mosquito.
landing gear. This is a nice feature that allows for inspection of the interior of the landing gear well even when the landing gear is retracted. The air fitting on my Mosquito is in the aft end of the landing gear well. By manually opening the gear doors, I am able to pump up the air system without extending the landing gear.
The aft door stop is shown here. It extends approximately 1/8 inch beyond the edge of the door opening in the nacelle.
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PIPER PA-25 PAWNEE DESIGNED AND BUILT FOR HEAVY LIFTING BY Hans-JĂźrgen Fischer
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he Piper PA-25 is an aviation workhorse. It was specifically designed for agricultural spraying, but it has been adapted for many other uses, including glider towing and the spray of chemicals to control mosquitos. As a result of its purpose-built design, the PA-25 has been very successful, with several thousand built and put into service, both domestic and international. The airplane was designed by Fred Weick. It first flew in 1957 as a prototype under the designation of AG-3. The airplane was first powered
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If it were parked on the ramp at airfield you would think it were a fullscale Cessna 182, not a Top Flite model.
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THE GREAT MOTOR/GENERATOR EMF DICHOTOMY
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his month I’ll be sharing two models with you. I’ll also tell you about a little-appreciated, but very important, characteristic of electric motors. First, let’s look at an inspirational model. CESSNA 182 This beautiful Top Flite® Cessna
The motor receives plenty of cooling air via the scale inlets. It exhausts thru a non-scale, inconspicuous belly outlet.
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BY Andrew Gibbs
182 Skylane was built by British Modeler Neil Jarvis. It’s a large —1/5.33 scale model — impressive high-wing model, with a wingspan that is 81 inches, as compared to the full size machine’s 36-foot span. The Skylane has been an extraordinarily successful airplane for Cessna; it was introduced in 1956 and is still in production. Neil’s almost-ready-
The wooden propeller is about the only thing distinguishing the model from the full-scale, which would use a metal prop. twitter.com/rcsportflyer
The Cessna’s flaps are large and effective. The scale hinging lets a gap open between wing and flap when they are deployed.
The tail area of the Cessna 182. The swept fin and rudder is a significant signature feature of Cessna high-wing singles. Neil’s Cessna 182 looks very realistic as it flies past for a photograph. The working port navigation light can be seen.
POWER LOADING Power loading is the ratio of the power delivered divided by the model’s weight. With 1100 watts powering this 12.5-pound model, the power loading works out at 88 watts per pound (1100 divided by 12.5 = 88). It is interesting to compare this to the full-scale aircraft, which has a maximum takeoff weight of 3100 pounds and an engine with 230 horsepower (172 kilowatts). The full-scale’s power loading works out to be 55 watts per pound (172,000 divided by 3100 = 55). I’ve often found scale models are comfortably able to use power loadings that are about the same as the full-scale machine. In this case, the model’s power loading is significantly higher than the full-scale airplane’s, indicating the flight performance is probably relatively better than that of the full-scale aircraft at maximum takeoff weight. to-fly (ARF) version weighs twelve pounds, eight ounces in readyto-fly condition. It is an all-wood construction, but even so, it has an excellent scale appearance. POWER SYSTEM For me, one of the most interesting aspects of any electricpowered models is its power system. In gas form, the Cessna 182 Skylane is designed for a two-stroke .61- to facebook.com/rcsportflyer
.91-cu-in.-size engine, or a .91- to 1.20-cu-in. four-stroker. Neil obviously opted to fit his model with an electric motor. The model’s system consists of a 410 Kv motor and an 80-amp ESC that are married to a 6S 4000-mAh LiPo battery. The motor turns a 15 × 10 propeller. At full throttle, this combination delivers 1100 watts of power for the airplane.
WING LOADING AND FLIGHT PERFORMANCE The wing loading is another statistic of interest to the modeler. The wing loading is the ratio of the wing area to the model’s weight. In this case, the wing area is 906 square inches, or 6.29 square feet. The weight is 12.5 pounds, or 200 ounces. These values result in a wing loading of 31.8 ounces per square RC-SF.COM
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Tim Schelhaas is a 3D helicopter pilot who competes professionally and has been an avid modeler for more than 20 years. He works at a local hobby shop that has been owned and operated by the same family since Neil Armstrong walked on the moon, but nothing could prepare him for...
THE INVASION OF THE MULTIROTORS IT’S IN STOCK AT TAMMIE’S HOBBIES
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A competitive acrobatic helicopter pilot, Tim Schelhaas has worked at Tammie’s Hobbies in Beaverton, Oregon for the past six years. Over the past three years, he has watched multirotors grow to dominate the shop’s sales of model aircraft.
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Tim Schelhaas demonstrates the performance of the Blade Nano QX quadcopter — which he steers new pilots towards before they start flying larger, more expensive aircraft.
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he first time I saw a First-Person View (FPV) quadcopter was maybe a little more than three years ago,” Schelhaas told me. “A customer brought it in — he was looking for spare parts, but unfortunately we didn’t have any to sell him. “I remember thinking that it was kind of a cool idea — being able to fly with a camera and looking at a screen or through a pair of goggles.” A cool idea, maybe, but neither Shelhaas nor the family who runs Tammie’s Hobbies in Beaverton,
BY Lucidity, Roswell Flight Test Crew
Oregon, saw much of a future in the gangly aircraft or its unorthodox control scheme. You don’t survive for more than 50 years in hobby business by pouring money into every oddball product that comes over the transom. “A lot of times, when something new comes along, you can’t tell if it’s a fad or if it’s going to stick around for a while,” explained Schelhaas. Even when he got the opportunity to fly a multirotor for himself, he came away unimpressed by the experience. twitter.com/rcsportflyer
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Tammie’s Hobbies in Beaverton, Oregon, stocks multirotors from well-known brands such as DJI, Gaui and Blade — as well as a host of other manufacturers — in addition to the spare parts.
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In addition to multirotors, Tammie’s Hobbies also sells components for complete First-Person View (FPV) systems, including circular polarized antennas and other specialty items previously available only from online retailers.
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Top performers from the 2013 holiday shopping season, the Blade Nano QX and the Estes ProtoX, out-sold fixed-wing aircraft by ten to one.
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“I kind of fought it at first,” he said. “They were just too easy to fly. I didn’t think they were challenging enough — but now I understand what they are for.” ENTER THE DRONES To Schelhaas’ surprise, customers kept coming in and asking for multirotors — us among them. The notion of the “Roswell Flight Test Crew” had not even occurred to us at that point. I was just another novice RC pilot trying to teach himself to fly the Gaui 330x, with its original GU344 flight control system on board. That was not the best approach, I’ll admit. Eventually, I relented and picked up a copy of RealFlight to master the basics in a consequencefree environment, but in the meantime, I was purchasing spare parts on an industrial scale.
Fortunately for me, I could find them at Tammie’s. “The Gaui 330x was the first multirotor that we had available to us,” Schelhaas recalled. “Our suppliers had a very limited selection at that point. It was frustrating at first, because our customers would come to us, wanting to support their local hobby shop and we had to turn them away, because we just couldn’t get product.” According to Schelhaas, his suppliers had to climb up the same learning curve that he and his colleagues at the retail level had already surmounted. “They were scared at first, because it was something new,” he said. “Once multirotors caught on, they became a huge part of their business — it actually saved them from going under, in some cases.” 4
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It hardly seems necessary to mention this fact; however, for the record, I am a huge fan and outspoken proponent of multirotors. I believe that these robust flying machines — paired with FPV systems and other remote sensing technology, as well as sophisticated flight control systems — are going to drive a revolution in unmanned aircraft that will rival the Internet in terms of its social impact. I really, truly believe that — and yet I was gobsmacked, as our friends across the pond would say, when Schelhaas told me how much the multirotor segment has grown over the past three years. “It took me by surprise,” he admitted. “It went from being nothing to probably about 75 percent of the market today.” Thinking I hadn’t heard him
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CARBON-Z CUB BNF BASIC TAKE THIS ONE BUSH FLYING FOR BACK-COUNTRY FUN
BY Wil Byers
At just over 1400 feet ASL, the E-flite Carbon Cub makes an approach for a possible short bush type landing on the top of Kiona Butte, WA.
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ull-scale Carbon Cubs are built by CubCrafters, which is located in Yakima, WA. It was founded by and is still owned by Jim Richmond. Jim basically remade the venerable Piper Cub by at first rebuilding and modifying Cubs. Then CubCrafters started making aftermarket parts. That business grew until eventually CubCrafters began making FAA certificated Cub-like airplanes, which are branded as CubCrafter® airplanes. These are the Sport Cub S2, the Top Cub, and the Carbon Cub SS.
E-flite’s 84.6-in. wingspan Carbon-Z Cub BNF Basic is designed to give RC pilots the thrill and excitement of flying a bush type airplane. However, the E-flite model sells for a whole lot less than the fullscale aircraft, but is just as much fun to fly as the CubCrafters’ machine. What you are going to like about the E-flite Carbon-Z Cub is how quickly you’ll be able to have it flying. That is because the airplane is a Bind-N-Fly™ Basic machine. BNF means quick assembly, and in this case it will take you only about 90
minutes to have your Carbon-Z Cub ready to fly. The Carbon-Z Cub is also electric-powered by an E-flite BL50 outrunner motor. So it is clean and quiet, but powerful! The model sports vortex generators on the wing for steep takeoffs and low-speed landings. This is especially the case when you lower the generously sized flaps. They let this model make steep approaches and fast climbouts. The Cub also comes with a set of big, bush type tires, so it does well taking off of or landing on grass.
Check out the vortex generators and the bush tires on this Cub. It is perfect for flying into that back country area or lake, when equipped with floats. facebook.com/rcsportflyer
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F4U CORSAIR WWII ACE MAJ. ARCHIE DONAHUE’S CORSAIR IS YOUR WEEKENDER
BY Staff
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he Chance-Vought F4U/AU Corsair is likely best known now for the fact that Marine Major Gregory “Pappy” Boyington flew his Corsair to distinction in the Solomon Islands as part of the Black Sheep squadron. Boyington was credited with 22 kills in his U.S. Marine Corp F4U Corsair.
Other WWII Aces found the F4U Corsair a formidable fighter too. They include Major Archie Donahue and Lieutenant Commander Ira Kepford. Archie Donahue flew his F4U to make 14 kills, while Ira Kepford had 16 confirmed kills in his. While the F4U Corsair primarily saw service in World War II, it was
also flown in the Korean conflict. Because of its versatility, and as an aircraft that could fly from ground bases as well as from U.S. Navy carriers, there were 12,571 F4Us built. Production spanned from 1940 until 1953. It is worth noting that there were sixteen different models of the F4U. It was even modified to become
This is RC-SF’s art director’s rendition of what Archie Donahue’s F4U Corsair Weekender would look like flying home after a mission. facebook.com/rcsportflyer
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