| ELECTRIC DUCTED FAN
F-16 MODEL JET. By David Jacques |
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Dave, out standing in his field !!! |
During a visit to the Dortmund model show last year, I
noticed a F16 model on one of the stands. My interest was drawn to the
model because it was of similar size to my previous F16 pusher prop driven
EZ ARTF kit, which I had been impressed with. The Dortmund model was classed
as an exact scale EDF and was manufactured in Holland. A brief talk to
the model designer and a look at a video on the stand created further
interest. On returning to Barrow I contacted the company through e-mail
and subsequently placed a order with them. I had to go on a waiting list,
but after a couple of months delay the large box arrived. I would class the model as an ARTF kit, the white epoxy fuselage which was in two halves had already been joined together and also had the lamina airflow duct (which was carbon fibre reinforced) moulded in, all panel lines had been reproduced on the surfaces. The wings and tail planes are made from foam with a 1mm balsa wood covering, the main spar is a 5mm dia carbon tube which connects to a carbon fibre reinforced plywood bulkhead in the fuselage. Two miniature servo’s operate the tail plane elevators and the receiver is positioned with velcro behind the main bulkhead. Access is gained through to the drive section through a large carbon fibre top panel which also gives access to the two stick battery packs and receiver battery. |
| The kit also provided cardboard jigs to align the wings and tail nozzle to the correct incidence angles when being glued with epoxy resin. The step by step instructions included photographs which guide you through the various stages of construction which are very straight forward. When the wings and tail plane had been correctly aligned to the fuselage they have been covered in thin tissue paper and sealed with a couple of coats of clear dope, when dry the complete plane was light sanded and sprayed matt white underneath matt gray on the upper surfaces. The chosen colour scheme was of the 86 TFW RAMSTEIN 316 Air Division in Germany. The panels and other insignia have been hand painted (panels shaded to highlight the edges) The wing lines are trim tape, painted with matt white to get rid of the surface gloss. The pilot and canopy give the model a scale appearance. The four bladed ducted fan rotor and shroud (with fixed stator blades) comes in one unit and has already been factory balanced. The motor fits in a pod behind the fan and also encloses the controller. Cables to the batteries and receiver leave the pod through a top access sleeve. When assembled the drive unit slides into the fuselage and the front flange is glued direct on to the intake extension, a clear transparent thrust tube is then fed into the fuselage and provides a smooth flow of air to the rear exhaust nozzle. The model uses program mixing to give elevon mixing on the tailplane ( aileron setting +/- 11mm and elevator +/-7mm). Also for landing “up trim” was achieved by using the air brake function switch which was set to give +1.5mm. Setting these accurately is important and also the C of G position which has been clearly defined by notches on the fuselage. | |
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Inside the Jepe F-16 |
The failsafe is also important to ensure the motor switches off with loss of signal from the TX (this is programmed into the Kontronik controller by the manufacturer). The model uses 15 cells but it is recommended to reduce the number for initial test flights, so to start off I have wired up 14 cells to see how it would perform. A range check with the motor running ensured no radio interference and that I had every thing working in the correct direction and that I had enough range. The next step was the bungee launch, with the metal stake hammered into the earth, (along side the Walney runway) the bungee was stretched to nearly full extent and the plane hooked on to the two wheeled dolly, with the motor on full revs Kevin released the model (take off’s are a two man job), a touch of up elevator ensured a smooth take off and gradual climb rate building up the speed the first turn was smooth with no reduction in speed, a couple of passes up and down the runway plus a roll was impressive and my thoughts turned to landing, with the motor on about ¼ throttle, Kevin switched in the air brake function, It did slow the model but I expected more lift, (unfortunately there was hardly any wind) when the plane was brought round for a landing approach onto the grass adjacent to the runway, with the motor off the glide was fast with hardly any loss of speed. |
| The model eventually landed about 50
yards away in patch of rough tufted grass, the low intake stopped the
model dead and caused the two stick battery packs to come forward and
out through the nose of the fuselage. (which had opened along the horizontal
seam) No other damage was evident and quick check showed the radio/
fan etc were ok. I was pleased with this first flight and I have since
put more strips of velcro on the battery sticks to hold them in more
securely, the fuselage nose seam has been re-glued and is ready for
further flights. Although the flight was only for a couple of minutes,
I can now look forward to longer flights to evaluate the model to its
full potential. This has been my first introduction to this type of
Electric Flight and I have been impressed by the power output from this
fan unit, the flying characteristics and the jet type of noise produced
by the plane in flight. The lack of Flight box and only a charger needed
to connect to your car battery, plus a clean model , I think I will
be looking for another EDF model in the future. Many thanks to David Jacques for the review.
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