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Written by Jon Barnes
Find out what is required to move up to the jet age
Feature
As seen in the August 2019 issue of Model Aviation.


Why do pilots typically find themselves interested in flying electric ducted-fan (EDF) model aircraft? Although the reasons vary, many pilots are drawn to the sheer excitement offered by jet models. Most modelers probably start with a more traditional, electric-powered aircraft with a propeller. Pilots who enjoy flying scaled-down, realistic-looking versions of full-scale aircraft have an abundance of historical, propeller-driven aircraft from which to choose.

Should a pilot wish to fly a scale model based on military aircraft from the middle of the 20th century onward, chances are that the model will be a jet.

scale, sport, and everything in between
02. Scale, sport, and everything in between! FMS offers a variety of 70 mm and 80 mm jets. (L-R) 70 mm F-18, 80 mm Hawk, and 70 mm ViperJet.

As a pilot’s skillset continues to develop, he or she is often drawn to more advanced models that offer greater piloting challenges. Jets are typically faster, higher-performance models that demand more advanced piloting skills.

Near the end of the 20th century, RC modelers who were interested in flying jets had several options. Pilots with deep pockets could satisfy their need for speed with traditional wood or composite-construction models powered by newly available, small aircraft turbines.

Although the wow factor of these turbine-powered models has always been off the charts, the expense of ownership and turbine waiver requirements has generally reserved this type of jet model for a small group of modelers.

Pilots with limited hobby funds who were nonetheless determined to fly jets at the turn of the century could either use a hard-to-find pulse-jet engine or the more commonly employed high-rpm, two-stroke internal-combustion engine driving a multiblade impeller mounted in a shroud.

The latter option required that pilots wring every last bit of performance out of it in order to generate the thrust necessary to get the model down the runway and into the air. Pilots needed patience to tune and retune the finicky, tuned-pipe, header-equipped ducted-fan engines, and the models almost always seemed to reside roughly six blocks deep on the wrong side of the power/performance curve!

Welcome to the 21st Century!

The turn of the century saw several exciting technologies emerge and converge. The result for modelers would prove to be a veritable cocktail of electronic excellence—one that would ultimately lead to affordable, high-performance electric jets for the masses!

With the arrival of the higher-power density and delivery capabilities of LiPo batteries (replacing NiCd and NiMH cells), brushless DC motors, and ESCs (that signaled the end of heavier, less-powerful, brushed DC motors), electric-powered RC aircraft entered a new millennium.

The amazing capabilities of these new technologies are showcased in EDF-powered jets. Although foam-composition models had been available for decades, the 21st century saw designers and manufacturers create a level of quality and detail that was lacking in earlier iterations of foam-based models.

Fast forward to the last 5 years or so and EDF enthusiasts have been living their best lives! High-quality, mainly foam-composition EDF jets have been released at a wallet-destroying rate. A relentless stream of EDF jets, in a variety of sizes and prices, have been released by the likes of Freewing (distributed in North America and Europe by Motion RC), E-flite (distributed by Horizon Hobby), FMS (distributed in North America by Horizon Hobby), HobbyKing, and more. Many models are offered in almost 100% turn-key plug-andfly (PNF) configurations, with pilots only needing to supply a radio system and a flight battery, and spend an hour or two assembling them.

from small to large, edf pilots who are interested
03. From small to large, EDF pilots who are interested in exploring a twin can opt for the E-flite UMX 28mm A-10, the FMS 70mm A-10, or an even larger 80 mm A-10 from Freewing (not pictured) that can be upgraded to a 90 mm power system!

Because many pilots enjoy sourcing even higher-performance EDF power systems, ARF or kit-only versions are sometimes available. These versions typically omit the fan and ESC, allowing pilots to provide and install their own choice of power system. In the last decade, EDF impeller technology has evolved from the original four- and five-blade rotors—known for their ability to generate unpleasant, ear-piercing banshee shrieks when at full rpm—to higher blade count rotors capable of emitting lush, turbinelike acoustics.

Although most EDF jets fall into the scale category, pilots can also select from a number of fantasy-based sport jets. This sport category of EDF jets is typically free from adherence to any level of scale fidelity and they are often engineered to achieve all-out speed and performance.

a scale jet dressed out in a pseudomilitary
04. A scale jet dressed out in a pseudomilitary color scheme. With receiver-embedded AS3X and SAFE technologies, the E-flite 70mm Viper qualifies as a good first EDF jet.

the flex innovations 90mm flexjet
05. The Flex Innovations 90mm FlexJet has an amazingly wide flight envelope. The included Aura 8 flight controller, with its preprogrammed flight modes, helps EDF pilots who have a variety of skill levels ease into 90 mm EDF jet ownership.

Pilots have a variety of EDF sizes and shapes from which to choose. Let’s take a closer look at some of them.

28 mm to 68 mm

The smallest EDF-powered jet models that are currently available in the mass-produced market are the UMX series of micro-size EDF models from Horizon Hobby. These small jets are powered by 28 mm diameter EDF fans that utilize low blade count rotors and high-Kv brushless inrunner motors. The type and variety of UMX-size jets distributed by Horizon Hobby has varied through the years. EDF pilots who are interested in starting small can choose between a MiG-15 and a twin EDF-powered A-10 Warthog.

edf jets perform best when using high-quality
06. EDF jets perform best when using high-quality, high discharge-rating LiPo batteries. Pilots interested in flying 70 mm, 80 mm, and 90 mm EDF jets should buy six-cell 3,200 mAh and larger battery packs.

Both models are available in BNF kits, which means that a pilot only needs to supply an appropriate size and capacity two-cell flight battery and a Spektrumcompatible transmitter. With respective flying weights of 3.75 ounces and 5.9 ounces, these featherlight models would appear to be best flown on calm days. Thanks to gyro stabilization technologies (AS3X and SAFE) embedded in the included receivers, these tiny jets fly like much larger models and can even be flown on breezy days.

SAFE mode offers less-experienced pilots the benefit of pitch and bank angle limitations, which can help mitigate the tendency to overcontrol a model. Another tangible benefit of the embedded technologies is that should a pilot lose orientation or become confused, a panic mode recovery option will level the model’s wing and give the pilot time to regain control!

Aircraft in this size and class typically include removable fixed gear for rise-off-ground-style departures and arrivals. A second option is to remove the fixed gear, hand launch the jet, and recover it by belly landing it in the grass.

These micro jets offer an attractive and affordable way for pilots to test the EDF jet waters.

Nearly a decade ago, a diverse series of 50 mm sport-scale EDF jets from Sky Angel fairly ruled the sky. Although the included fan was not necessarily known for its power or thrust, the jets, when flown on the stock configuration, were lightly loaded. The Sky Angel 50 mm hangar originally included the F-86, F-16, F-18, A-4, L-39, Hawk, T-33, F-35, F-22, and others.

Many pilots have found these smaller jets to be a great platform into which they can install more modern, higher-performance 50 mm EDF power systems. Although not as popular or widely available as they once were, the smaller jets can still be found at several online retailers. Those in the US who are interested in exploring the once-popular series, might want to check out Banana Hobby. Several overseas online hobby shops are also known to stock a limited selection of these foamie jets.

Moving up in size, an expanding series of 64 mm scale jets has been released by Freewing during the past year or two. Based on lesser-modeled aircraft, these 64 mm EDF-powered jets are distributed by Motion RC. Available models include the F-105 Thunderchief, an F-8 Crusader, and the fairly obscure Lippisch P.15.

Additional legacy models are available and multiple new ones are reported to be coming soon. These might be attractive to EDF pilots because they fly on threeand four-cell LiPo battery packs. Pilots bitten by the speed bug should opt for the little Lippisch. Its stock 64 mm power system, when flown on a three-cell battery, transforms this little flying wing into a speedy jet! Swap out the stock power system for a four-cell-based EDF, and the Lippisch can gain a pilot admission into the 100-mph club!

Another recent offering that utilizes a 64 mm EDF power system is E-flite’s camouflage blue and grayschemed F-15. The fan used in this model offers a higher blade count than the Freewing 64 mm jets, resulting in more pleasing acoustics.

the heart of the beast
07. The heart of the beast! When assembling a new EDF PNF kit, make sure to inspect the motor-to-ESC connections. It is usually a good idea to secure the connections with electrical or 3M Blenderm tape.

Embedded stabilization technology allows inexperienced jet pilots to acclimate to flying an EDF jet. Like most of the EDF models of this size and in this class, these aircraft feature removable, fixed, tricycle landing gear. The smaller size typically precludes them coming equipped with retractable landing gear.

70 mm to 80 mm

Moving into the larger 70 mm and 80 mm EDFpowered jets, pilots can expect models with enhanced functionality and additional attractive features. The caveat that must be mentioned at this juncture is that models in this size and class are nearly always powered by six-cell power systems. This can require pilots who are accustomed to using smaller batteries to commit to buying and building an inventory of six-cell packs.

Most 70 mm and 80 mm EDF-powered jets that are manufactured these days feature electric retractable landing gear, flaps, factory-installed lighting systems, and other enhancements. The larger size of these jets permits manufacturers to create a higher level of detail in the molds and use supplemental plastic composition parts. Because bigger flies better, these larger jets are less susceptible to poor weather conditions and wind.

There is an astonishing variety of mainly foam-composition jets that are available in this size and class. A quick summary of some of the latest releases includes the E-flite 70mm Viper Jet and 80mm F-4 Phantom; the Freewing F-35 70mm and L-39 80mm Albatros; the FMS 80mm Futura and 70mm Avanti; and the HobbyKing 70mm SkySword.

Pilots who want a good, entry-level 70 mm jet might want to check out the Viper. Its embedded gyro stabilization technologies (Spektrum AS3X and SAFE) allow fliers to progressively hone their EDF skills. Those with more experience and who are attracted to scale jets will have a tough time deciding between the Phantom, the L-39, and the F-35! All three have a high level of scale realism, are feature rich, and include high-performance, high blade count fans.

A variety of sport jets are available in this class. FMS offers pilots a choice of either 70 mm or 80 mm sport jets with its Avanti and Futura models. These aircraft offer triple-digit speeds and beyond. One of the slickest fantasy-schemed sport jets currently available is the SkySword. This stiletto-shaped jet looks like it came straight out of a science fiction movie! Available in either a neon pink or canary yellow color scheme, the SkySword is perfect for those who are attracted to unconventional-looking models.

90 mm and Larger

Jets powered by 90 mm and larger fans are the crème de la crème of the EDF jet world. Their larger size allows manufacturers to achieve the highest levels of scale detail and realism possible in the EPO foam manufacturing process. Most of the models in this larger class are powered by 90 mm EDFs, although there are a few 105 mm and 120 mm (and maybe even larger) mass-produced EDF jets available.

high blade count edf power systems
08. High blade count EDF power systems are generally standard equipment on the latest generation of EDF jet kits.

a close-up of the impeller used in a typical edf
09. A close-up of the impeller used in a typical EDF unit. Although high blade count fans create a larger net current load than lower blade count fans, their turbinelike acoustics and in-flight performance are hard to beat!

Although most of these larger EDF jets utilize sixcell power systems, manufacturers often make a higher 8S power system-equipped version that is available for pilots who place an absolute premium on performance. Pilots might need to go with a higher channel-count receiver to fully take advantage of the features included with some of these big jets.

Another development that is taking the scale realism of these larger EDF jets to an even higher level is 3D-printed parts. Motion RC has been developing and sharing the files so that pilots can print incredibly detailed 3D cockpits and other assorted scale goodies.

Although it has been available for a few years, the Freewing Super Scale 90mm T-45 Hawk stands out as what manufacturers are capable of achieving. This gorgeous red and white U.S. Navy-schemed jet includes leading edge slats, speed brakes, sequenced gear doors, and a full set of LED navigation lights and strobes. The sight and sound of this supremely scale jet is what EDF jets are all about!

Another notable 90 mm jet is the Flex Innovations FlexJet. Although it looks like a modern military jet trainer, this model is actually a fantasy-schemed sport jet. The FlexJet, which was recently made available in a vectored-thrust variant, boasts and benefits from an included, preprogrammed Aura 8 stabilization system. Pilots only need to configure the transmitter to select between the available three or four preprogrammed modes.

Every nuance of this 90 mm jet’s in-flight performance envelope has been vetted and explored by Flex Innovations team of world-class pilots, with the resulting embedded in the Aura 8.

Pilots who are looking for the ultimate in a large, high-performance, high-power sport jet—even those who are newer to the genre—will find the Aura 8-equipped FlexJet amazingly easy to fly in the tameddown flight mode. As pilots gain proficiency, they can progress to more advanced flight modes and unlock this model’s full potential.

Piloting Skillset Required

As compared with flying propeller-driven aircraft, pilots will always need to stay ahead of their EDFpowered models. Although propeller-driven models typically respond almost instantly to any increase in throttle, EDF-powered jets have a slight lag in response to the throttle.

Additionally, newer jet pilots should always remember to pull the throttle stick back to a moderate, midstick position after taking off. Leaving the throttle wide open will result in many jets screaming across the sky at triple-digit speeds and taking on an almost indistinguishable silhouette in mere seconds.

The high blade count EDF power systems used in the current generation of EDF jets can pull a lot of current from a flight battery. Although the actual flight length is ultimately dependent upon a pilot’s throttle usage, the flight durations of EDF-powered jets tend to be shorter when compared with those of their propeller-driven cousins.

the scale and realistic appearance
10. The scale and realistic appearance of the Motion RCdistributed Freewing Super Scale 90mm T-45 Goshawk is gorgeous!

Pilots who use the transmitter countdown timer feature should start with a 3- to 5-minute time and adjust it as they gain familiarity. Good-quality, high discharge rate LiPo batteries are suggested. Fliers should be cautious of the intense, maximum C rating that many LiPo manufacturers have claimed—maximum discharge ratings of 100 and higher are sketchy at best. Quality, name-brand 40C LiPo batteries should be adequate and will generate good results when used in EDF jets.

When it’s time to land, the most important thing to remember is to carry a little speed because EDF jets typically react slowly to throttle increases. It is best to understand the model’s stall speed before attempting the first landing.

Conclusion

The sky is truly the limit when it comes to EDF jets, and there has never been a better time to be an EDF enthusiast. We’re past the halfway point of 2019, and an impressive number of new products has already been released! An 80mm Havoc sport jet from E-flite claims to be good for 10-plus-minute flights and top speeds of 140 mph. A 90mm F-22 Raptor from Freewing and MotionRC, with a Blue Angel-schemed 90mm F-18C hot on its tail, are in the prerelease ordering phase.

With the explosion in 3D printing technology, some pilots have even designed aircraft that can be printed. EDF enthusiasts with access to a larger, table-equipped 3D printer might want to check out the 3D-printed 120 mm L-39 by RCGroups user Lynxman (search on RCGroups for 120 mm 3D printed L39)!

Pilots who enjoy installing higher-performance EDF power systems in their jets might want to connect with Gary at EffluxRC. He has been in the business of providing EDF power systems for many years and can knowledgeably suggest upgrades to many of the jets that are currently available.

Finally, many pilots prefer a unique model—one that does not look like every other jet. The easiest way to create a custom graphics scheme for any EDF jet available is to grab some quality custom vinyl graphics from Callie Graphics. Callie knows how to scale artwork to fit on any size and class of models and the results are always stunning.

find out what is required to move up to the jet age
01. The new Motion RC/Freewing 70mm F-35 Lightning II Version 3. The Version 3 moniker illustrates how some manufacturers periodically update a popular jet model to further enhance its scale realism and more fully take advantage of advances in EDF power systems and electronics. Photo courtesy of Motion RC.


SOURCES:

Callie Graphics

info@callie-graphics.com

www.callie-graphics.com

EffluxRC

(661) 609-7470

effluxrc.com

Flex Innovations

(866) 310-3539

www.flexinnovations.com

HobbyKing

www.hobbyking.com

Horizon Hobby

(800) 338-4639

www.horizonhobby.com

Motion RC

(224) 633-9090

www.motionrc.com

Banana Hobby

(626) 629-8552

www.bananahobby.com

RCGroups

www.rcgroups.com

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