Can Freewing’s stunning version of Aero’s high-performance jet trainer change Simon Cocker’s views on EPO and EDF?
Graham Ashby (RCM&E former editor) has reviewed a number of scale models from the Freewing range in the past and when chatting to him he’s been genuinely passionate about his collection of foam warbirds. He convinced me that with care they can be kept pristine, being structurally sound enough to absorb a degree of knocking about and able to withstand some aerial abuse, with flight performances providing the real scale effect of the type. His positivity warmed me to the whole concept of an EPO-based RTF, which opened the door to ticking off an item on my bucket list.
For many years I’ve harboured the desire to fly an L-39, be it jet-powered or a big PSS, and with Freewing’s EDF version purporting to offer sport-style performance in a scale package it seemed just the ticket, particularly as it will take off from short-grass runways, which is all I have at my disposal. With a collection of 6S LiPos already to hand I decided to take the plunge, the PNP version reviewed here arriving complete with EDF unit, ESC and servos, and requiring a six-channel Tx and Rx, LiPo and charger to complete.
I was delighted to open the superbly packed box to find all the components in perfect condition, sitting neatly in their negative shells so they couldn’t rattle around in transit. Feeling and examining the individual components quickly gave the assurance that I was handling a beautifully designed and engineered product where love and attention to detail had been lavished without restraint. It invites respect from the word ‘go’ thanks to the perfection of its presentation, level of finish and consideration to scale fidelity.
The solid feel of the airframe parts belies the EPO label that I previously disliked so vehemently. Beautifully spray-painted outer surfaces disguise the foam to provide a crisp, even surface finish that’s smooth and solid in texture, with clean, sharp lines between the different colours – quite superb.
With the supplied bag of screws and control linkages the airframe assembles within an absorbing hour or so, which includes connecting the multi-function control box that provides power to the lighting system and accommodates the wiring harness that links to the wings, picking up the aileron, flap and mains retract servos, and tip tank lighting wires. Rigging the model is therefore a painless and speedy process, although at 41.5” (1054mm) span the L-39 sits comfortably in my car fully assembled.
Eight good quality 9g servos are supplied, one for each individual flying surface, with three screw jack motors operating the retracts. A tube of foam-friendly glue is supplied to secure the rear fuselage section and the plastic nose cone.
Opening the bags continued to reveal more detailed parts, including under-wing fuel tanks that slip on securely and are secured by strong magnets, along with scale wing guns that glide into their l.e. housings and can be instantly removed. A scale cannon housing clips on the underside of the fuselage behind the nose leg bay.
Two plastic antennae are supplied, one of which is glued into the tip of the fin and the other under the front of the nose – it’s little fussy bits like this that really help achieve a true scale effect.
The detail of the tip tanks is excellent, with a working headlight bulb and navigation lights. The cockpit arrives complete with the interior details and two pilot figures fitted, the whole arrangement fitting securely to the fuselage with strong locating magnets and a spring latch pin.
Neat, embedded nylon knuckle hinges are fitted to all the control surfaces, ensuring strength and longevity. The foam material is still intact, too, so an aerodynamic seal of the hinge line is also preserved.
The retracting U/C is sturdy and beautifully made, with trailing link sprung legs that help to make landings a joy. The nose leg is operated by a dedicated direct-linked servo for accurate steering and it has a scale retracting door. A built-in five-second delay helps prevent inadvertent switch-knocking from straining the retracts when the aircraft isn’t posed for their use. Smooth and with scale speed deployment, tucking the retracts away immediately after take-off looks so right, adding wonderfully to the piloting experience.
POWER AND SET-UP
Recommended for a 6S 4000 - 5000mAh LiPo, delivering power through the 100A ESC (c/w 5A BEC), the 12-blade, 80mm diameter fan is a powerhouse of a unit, delivering ample thrust from the pre-fitted and factory-balanced 3530/1850kV brushless motor.
Setting up the L-39 is intended to be very simple and indeed it was. Using a six-channel Jeti Rx, the model was flight-ready after just 20 minutes of programming. The flap setting has two positions, half deflection for take-off and full deployment for landing, while I employed the rate switches to offer two control options for aileron and elevator, i.e. positive exponential of 30% on full control surface deflections and 20% at reduced rate settings.
Thus far my L-39 experience had been nothing but a pleasure. Assembling and programming the model proved to be absolutely fool-proof and enjoyable. Time, then, to see whether the same rang true with its airborne activity!
At my club’s grass-topped airstrip I pre-flighted the aircraft one more time and lined her up at the furthest point to provide room for a long, scale take-off. Power came on impressively and with the L-39 hurrying down the strip I hauled back on elevator... but there was no rotation before the runway expired, despite using take-off flap, full power and a boot full of pitch coaxing!
My next try was at the lovely strip at Middlewich, where my good friend Tom Doyle had invited me to conduct the flight trials. I was nervous about the menacing trees that border the end of the runway and the crosswind that was threatening to push the model in that direction, so I decided to quit while I was ahead.
I then attempted to take off from Jim Glasgow’s club site at Kilton, where the perfectly smooth grass strip should have offered the ideal take-off venue, but the L-39 ran off the end of the strip into the long grass, damaging the nose leg and breaking off the gear door, two items that I was able to replace very quickly thanks to RC Motion’s speedy internet service. Although the airframe took quite a serious wallop in this incident it was reassuring to see that it could absorb the shock of such an arrival without damage.
C RATE CRITICAL
Scratching my head, I researched EDF LiPo specifications to discover that the battery’s C rating is critical to achieving full fan performance. So, I invested in new 6S 5000mAh cells from three different manufacturers to investigate: 1 x 50C from Optipower, 2 x 60C Turnigy Heavy Duty from HobbyKing and 1 x 40C from Robotbirds.
THIRD TIME LUCKY
The third sortie was undertaken back at my club’s freshly mown grass strip. Fitted with the new Optipower pack the L-39 felt like its afterburner had been lit and the aircraft was eager to reach for the skies. As the model tracked purposefully, I progressively applied more elevator until the wheels finally left terra firma.
Although the detachment was sudden and not very pretty, once the U/C and flaps were tucked away the rate of climb was excellent. At a safe height the L-39 cruised around happily on just over half throttle whilst I adapted to the model’s feel and trimmed the controls a tiny amount.
I felt immediately at one with this lovely-looking jet, which was proving to be both stable and groovy. Being a PSS enthusiast (and wannabee jet jockey) I’m used to fast, low passes and here the L-39 is very keen to oblige. In a dive the model picks up speed instantly with power and, better still, the airframe’s mass enables retention of aerial energy into scale climb-outs and reversals. I was thrilled to finally be flying a truly punchy EDF model that sounds realistic, too. The multi-blade fan provides a jet-like sound on low passes that’s enhanced by the Doppler effect of its departure back up to cruise height - wicked fun!
Roll response proved to be very good, with perfect four-point rolls and lovely, crisp split-S manoeuvres, whilst the elevator was powerful without being grabby. Flaps proved delightful too, as they deploy in either mode without any pitch change once the model’s speed is reduced. Inverted flight is very comfortable, while the stall is benign and predictable and is only discovered if provoked by carelessness.
Armed with my new, powerful LiPos I returned to the Kilton club, where a tricky crosswind tested not only the L-39 but also my piloting ability. The model coped admirably, and it tracked as straight as a die before taking off perfectly well, although it took some coaxing to rotate due to the draggy grass. The C of G is positioned at approximately 20% chord, which is much further forward than the position of the main U/C legs and with the trailing links the wheel axle position is slightly further rearward still; the net result is that the nose leg becomes loaded, so the elevator has to work hard to combat this loading and allow rotation. Now I understand this to be the case, I simply gun the throttle at the outset, heave back on the stick and the L-39 detaches every time with no argument.
I’m certain that on a hard-surface runway the aircraft would transition smoothly, as it did so neatly on the beautifully prepared close-cut grass strip at Buckminster at the RCM&E fun fly weekend. The important point is that there’s now safety in airspeed with the correctly C-rated LiPos delivering that all-important essential thrust boost.
I quickly learned that EDF flights are short but glorious; four minutes is all you can expect from a 5000mAh LiPo so there’s not a great deal of reserve power in the tank for a go-around. It’s also imperative that the LiPos aren’t consumed below 30% of their capacity under load in order to preserve their longevity - they’re fragile items, both physically and emotionally! If you mistreat them, they’ll puff-up and their internal resistance will greatly diminish, and their cycle life can be compromised.
When flying PSS jets such as the B-52 or Canberra the timer rings when I hit the default one-hour setting, so when flying the L-39 you can imagine my surprise when the ringer blares at me after just four minutes! I’m only just getting into the groove after two minutes, so it acts as a fun spoiler alert and is very irritating.
I enjoy performing scale landing approaches with the L-39 on full flap and with that lovely scale U/C hanging in the breeze, landing lights on. The tip pods show up well too, so this is a joyous manoeuvre. It’s just as well this is so satisfying because with EDF there are plenty of take-offs and landings, and, of course, a number of LiPo packs are needed if you want to keep that greedy little power system fed. Once a flight’s been concluded the adrenalin is flowing and there’s an overwhelming urge to repeat the experience because it’s so exhilarating and addictive.
The HobbyKing LiPos have proved to be robust under load and are relatively inexpensive. Tim Mackay recommended them to me having been using them for some time in his Freewing Avanti, a model he uses as his regular fix, and they’ve stood up to considerable use without complaint so far. The Optipower LiPo provides just a smidgeon more power and (I’m told) should live longer than the HK packs.
At full chat the powertrain draws 85A, so it’s imperative to reserve this for bursts at critical points in flight, particularly as the model is quick enough in the down lines using just half power. I checked the decalage of the airframe, which shows just 1.5 degrees of positive incidence on the tailplane, enabling a safe margin of stability and minimum drag.
EPO AND EDF OK!
My EDF experience so far has been a revelation and most rewarding. I love the jet-style feel and looks of the L-39, the outstanding finish and quality of which gives that essential pride of ownership that ensures it’s a keeper. That it easily fits into the car without derigging is a bonus; the model is always ready for action subject to a LiPo being dropped into the fuselage.
Operating an EDF is so easy and thanks to Freewing all the hardware invested into the model is robust enough to provide a long life of trouble-free fun. When you tot up the cost of the individual components separately the £360 price tag becomes comprehensible and fair value. Should the airframe be destroyed there’s a strong possibility that most of these components could be reused as the entire airframe will then act as an active foam crumple zone!
I’ve finally come to accept that EPO works as an airframe material and this has encouraged me to invest in other foam airframes from Motion RC where I can use my stock of 6S LiPos - their A10 Warthog and the larger of the two Spitfires look particularly appealing.
The L-39 has proved to me that EDF has finally come of age, thanks to years of development and the embracement of new technology. This is a truly fine product with a pedigree performance that will get your pulse racing and possibly set you on a path towards the greater goal of owning a Jet A1-burning turbine at some point in the future.
One of the redeeming features of all EDF models is that they don’t require any support kit to attain a flying thrill. It’s a simple and quick route to jet-style adrenaline-pumping fun and I whole-heartedly recommend this little L-39 - for experienced pilots only, mind!
Crashing foam airframes isn’t an option as although repairs are possible provided the damage isn’t too serious, the end result won’t be pretty. A replacement L-39 fuselage will set you back around £92, a new wing is about £55. The comprehensive spares list does cover most eventualities, which is comforting to have as back-up.
For budding Jet Jockeys, then, the L-39 is the way to go. Rest assured that in exchange for your hard-earned you’ll receive a top-quality model that flies beautifully and will deliver an endorphin fix on each and every flight. Be sure to use good quality 50C rated LiPo packs and you may well be hooked for evermore on the range of foam models offered by Motion RC. Buckle up, don your Ray Ban aviator shades and go grab your share of the Top Gun experience!
Name: L-39 Albatros PNP
Model type: EDF jet
Manufactured by: Freewing
Available from: Motion RC - www.motionrc.eu
Wingspan: 41.5” (1054mm)
Fuselage length: 53.2” (1351mm)
Weight: 4.85 lb (2.2kg) w/o battery
Thrust: 7.4 lb (3.35kg)
Powertrain (supplied): 12-blade, 80mm dia. EDF c/w 3530/1850kV outrunner, 100A ESC c/w 5A BEC
Rec’d LiPo: 6S 4000 - 6000mAh
Functions (servos): Aileron (2); elevator (2); rudder (1); flap (2); nose leg steering (1); throttle (via ESC)
Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!