last update: 12/04/2003

It has been a few months now since I decided I wanted to start flying model aircraft again, after about a lapse of 10 years. Fortunately this time the web was around to help with, what was going to be, quite a search.

I was pretty sure what I wanted to try: Electric gliders. My previous flight experience was with pure sailplanes, and the 'new' electrically powered flight without the hassle of glow engines, looked very appealing.

The best electric glider I could buy in South Africa was a two meter T-tail, 600 engine powered glider. The flying experience left me disappointed. The glider was very underpowered, and exhibited a very bad wing stall characteristic when doing low speed turns. With the low engine power, takeoff was a hassle, and you could not actually try turning without fearing a stall. No need to mention this recipe for disaster turned out to be one!

While doing research on the web to figure out how to modify the 'flying pig' by adding ailerons, I came across a review of the Filip 600. The beautiful lines of this plane immediately caught my attention. It took me a very short while to find out that it is not available in shops locally, so I started looking at various online hobby shops and other online reviews of the Filip 600.

I found the Filip 600 on Hobby-Lobby (more about them later) in the USA, and was on the verge of ordering the Filip 600 from them, when I saw a mention of a 'Sport' version of the Filip on one of the discussion pages. One of the reviews I had found, mentioned a wing flutter that the Filip 600 experienced during a high speed dive. I was not really worried about the flutter itself, because I knew that thermal sailplane wings are not designed to do high speed dives. The Sport version of the plane had very stiff foam wings, that were covered in balsa and Oracover. The result is a very stiff by lightweight wing. The plane I was looking for had to be a hybrid that could do a bit of thermal soaring but also loops and rolls with the worry of the damaging the wings. A quick reply to an e-mail sent to Hobby-Lobby informed me that they unfortunately did not sell the Sport version.

An exhaustive search with all the best web search engines revealed very little extra information about the Filip Sport - unfortunately no reviews. I found a few pictures on one or two Czech sites, and came across the manufacturers site: RCM-Pelikan. The most important find I made however, was Puffin Models (more about them later as well) in the UK. A quick e-mail reply from John informed me that, not only are they the UK RCM-Pelikan agent, but also has a Filip 600 Sport in stock.

The last bits of kit that I would need to complete the Filip, was the power and remote control systems.

It became clear very soon that for the high performance plane I was looking for, the engine choice was between the ModelMotors AXI 2820/10 and the Jeti Phasor 30-3. Both are brushless motors. I went for the ModelMotors AXI engine because it is extremely light for its size and power. The brushless controller was a very clear choice of the Jeti 40-3P with BEC. The engine would be powered using 8 Sanyo 2400 mAh SCR cells.

The prop spinner and CAM blades was a bit of a tough search again - there are a lot to choose from . Eventually I decided on the 40 mm Turbo spinner used with many RCM-Pelikan models. It allows engine cooling through a hole in the front of the aluminum spinner. According to a number of reviews the CAM blades to use were the Aeronaut (Freudentahler) 12x8 8mm carbon fiber type blades. According to the specifications of the AXI motor using smaller blade sizes like 11x7 would be more efficient.

The radio I wanted I managed to buy locally. I decided on the JR X-378 because it is good value for money, and it supported a sailplane flying mode. I did not use the JR servos because of their size, but found in the many Filip 600 reviews that the favorites were the Hitech HS-81's for the ailerons and the Hitech HS-55's for the V-tail ruddervators. Both the Hitech servos have very good speed and torque numbers, considering their weight and size.

Many thanks to all the people before me who put their efforts and experience on the web for me to use. I hope to do the same for someone that comes across my page and find it useful.

It must be said, both the online retailers I have used so far impressed me very much. I all cases I had very quick responses to e-mails sent, care taken to ensure that delivery is on time and that I am happy with the end result. The whole ordering process ended up being a very international affair, with my completed airplane coming from 3 different continents. What really caused me the most gray hairs, was the currency exchange rate differences between Europe and the US. Due to the different rates for British Pounds and US Dollars, the US was the cheapest option in most cases.

As mentioned above, the Filip 600 Sport was ordered from Puffin Models in the UK. Puffin Models retails in models from RCM-Pelikan that I could find on no other English language website, and also stocks a lot of other components. After badgering John with a lot of questions via e-mail, to which he replied promptly every time, I ordered the following from him:

Filip 600 Sport Electric V-tail

During the transit from the UK to South Africa, the package (clearly marked as 'Fragile'), must have been dropped somewhere. The package was made up very well, but the underside of the box had a hole about 20 cm in diameter in it. Whatever made the hole punctured the plastic bag with the spare components, and also broke the wingtip of one of the wings.

I e-mailed John immediately to sort out the problem. John offered the option of a cash refund to repair the damage, or to send a replacement wing. I decided on the wing replacement. Now what followed is the real amazing part, and Puffin Models really earned my respect. John not only replaced both wings for free (I think because the colors were slightly different), but also had them on my doorstep within 3 days! No need to say, I am a very happy customer.

The Filip 600 Sport kit included the fiberglass fuselage, wings, V-tail, pushrods, control horns, screws and other components. The ailerons and ruddervators were already attached with hinge tape, and I saw no reason to remove them. The kit also included instructions for assembly and a very good checklist for the glider version of the Filip to calibrate the handling characteristics. The worked equally well on the electric version.

The rest of the components were ordered from Hobby-Lobby in the US. These guys also proved to be on top of their game. They have a wonderful website with a very large range of products (most with photos and complete pricing details). The one reason why I was so content ordering all the components from one supplier was Hobby-Lobby's great Low Price Guarantee. It basically says that if you can find any other US online retailer where the same product is cheaper, they will beat the price by 10% if the other guys have stock or match the price if they don't have stock. This is where my research on the web paid off - I knew where the cheapest components were sold. In the cases where it applied I supplied the details with my order to Hobby-Lobby. Don, a salesman there replied very quickly with: 'I appreciate the opportunity to match these prices'. Here is the order I sent them:

Model Motors AXI 2820/10 rotating can brushless motor
Jeti JES 40-3P Controller (with BEC)
8 Cell Sanyo CP-2400SCR NiCad pack
12x8 Aeronaut CAM Folding Prop pair (carbon fiber)
40mm Turbo Spinner for 5mm shaft
Hitec HS-81 Sub Micro servo (JR connector)
Hitec HS-55 Economy Sub Micro servo (JR connector)
40" Servo extension for JR or Hitec
Graupner Clear Hinge Tape, 32 feet

Once again the package was delivered in very quick time (approx. 4 days). The package arrived well packaged with absolutely no damage to the goods inside.

My experience with both retailers mentioned above, makes me very confident to recommend them to anyone even (or especially) if you live in the UK or the US. Well done guys!

I started the assembly by fitting the wings to the fuselage. I followed the instructions, and drilled two holes in the fuselage where the leading edges of the wing roots meet the fuselage. Two hardwood dowels epoxied into the leading edges of the wings slot into these holes keeping the wings firmly attached. The sturdy metal wing joiner required no additional work and fitted exactly into both wings.

The dowels that come with the Filip kit are about 2 cm long. I found that by replacing them with ones that are at least 5 cm long, the chance of damage to the wing on a rough landing is reduced. The shorter dowels are glued only to a short portion of the leading edge that is unable to handle larger forces. Increasing the length spreads the forces over a larger part of the wing root.

The wings are secured with two nylon bolts. These bolts are designed to shear off in case of a crash or hard landing. The bolts fit into blind nuts that are embedded in a piece of plywood epoxied inside the fuselage. Two additional holes need to be drilled for the bolts to pass through.

The holes in the wing where the nylon bolts pass through, has a plastic plug on the top part of the wing, but the rest of hole runs through wood. I found this design not to be strong enough to shear the bolts when needed, but to rather damage the wood. To solve the problem I strengthened the holes by putting aluminum tubes in them that are epoxied in place. The aluminum shears the bolts instead of breaking the wood.

Installing the plywood engine mount was very straight forward. I sanded the nose of the fuselage down, so that the spinner and the nose are the same size. The circular piece of wood is slightly oversize, and after sanding it down a bit, it fits tightly about 3 mm from the front of the nose. I first used a bit of CA to keep it in place and then epoxied it very tightly in place from both the inside and outside. The mount plate was installed with a bit of down and right angle.

The motor was bolted into place with two bolts. I tried to position it so that the ventilation holes match up with those on the motor.

The canopy confused me for a while, figuring out how exactly it is fitted onto the fuselage. Two fiberglass strips are glued to the inside front and rear of the canopy. I used an epoxy that remains fairly flexible after curing and this proved a very good choice after one or two harder landings. To fit the canopy the rear is slid on first and then moved backwards. It is possible to move it back so far that the front can clip on as well. The canopy is then moved forwards until it fits tightly. I normally secure it with a bit of Scotch magic tape to ensure a tight and smooth fit.

The battery installation was where I probably deviated the most from the assembly instructions. Most of the changes were done after I had a few flights under the belt already. The most important fact to remember regarding the battery is that it is a 1/3 of the flying weight, but in very compact size. Under conditions of quick deceleration, the battery has a lot of momentum, that you want to get rid of without causing damage to the plane. Because of its weight it affect the CG depending on the position inside the fuselage.

To solve the problem of dissipating the momentum of the battery, I replaced the supplied plywood battery tray with a pure balsa one. The think is that in case of a crash I would rather have the battery tray break and absorb energy, than to expect the fuselage to do so. Secondly, I also changed the position and size of the spruce lattice that supports the tray. Again the thinking is that it should rather break than go through the fiberglass. The change in the position of the lattice is to avoid the situation where the wood can act like a wedge and crack open the fuselage. By placing the lattice lower in the fuselage it could be shorter in length, so that when it comes loose, it is unable to wedge in anywhere.

Another modification was made to the battery tray. Normally the tray is supposed to be screwed to the spruce lattice, but I decided to rather attach it with Velcro. This had two main advantages: firstly it allows to tray to be moved forward or backward with relative ease - very easy to adjust the CG between flights, and secondly it could also come loose easier in a crash - again to minimise damage. The Velcro that is used to keep the battery in position overlaps about 1.5 cm only. The reason is that if too much of the Velcro overlaps the bond is too strong. In an actual crash, that battery stays connected to the tray and could cause damage.

Keeping the wires away from the rotating can of the AXI 2820/10 motor can be a bit of a problem. To those unfamiliar with the type of brushless motor, the AXI motor has a rotating can on the inside of the fuselage that is connected to the motor shaft. The is done to achieve a tremendous amount of torque from a relatively small motor. The problem is inside the fuselage because the three wires that is connected to the speed control could touch the motor while the motor is running. To get past this problem, I used a 3 cm piece of piano wire, made a small V shaped bend in it, and epoxied this to the inside of the fuselage. The wires could then be fixed to the fuselage with a cable tie.

Installing the speed controller was a straight forward task. I soldered the three supplied gold plated connectors to the engine wires and the speed controller wires, and insulated them with heatshrink.

When the RCM-Pelikan guys designed and build the fiberglass fuselage they did an excellent job. I had a few rough landings since mainly because my flying field has a few areas lately where the grass was about 1.2 meters (4 feet) tall. When a wing is caught by long grass there is not much you can do. The front part of the fuselage developed a few cracks that indicated there were a few areas that required strengthening. I bought a piece of woven fiberglass cloth but instead of using resin, I expoxied the cloth to the inside of the part of the nose and around the area where the wing roots are fixed to the body.

The radio installation was started by connection all the electrical systems with extension wires to make sure that there were no defective components. This also provided an opportunity to zero all the servo positions before they are installed.

I decided not to follow the V-tail servo installation instructions. The long pushrods were very thin, and gluing the tube to the inside of the tail did not look easy. The Hitech HS-55 servos are a perfect fit in the tail. The total height of the servo is less than the width of the opening across the tail, and both servos fit in there very easily.

Cut the holes in the tail first before the V-tail is attached. It makes the drilling and sanding a lot easier.

The control horns for the ruddervators were attached so that the piano wire control rods are parallel to the tail. I used the supplied plywood mount to strengthen the tail internally. Cut into two pieces the plywood was epoxied inside the tail aligned with the existing holes. I made sure before they were glued in place that the HS-55's fitted nicely.

The servos were installed with the servo horns in a forward position. This ensures that there is a greater upward movement of the ruddervators compared to the downward movement. The piano wire was cut to length and bent in place. Any additional trimming could be done via the radio's travel adjustment and zero settings. The radio also has a built-in V-tail mixer so that no external mixer was required.

The V-tail in the kit is already glued together at the correct angle. Some reviews I read suggested strengthening the bond - and even more so for a semi-aerobatic plane. After the V-tail was epoxied to the fuselage, I removed a 1 cm string of Oracover over the middle part of the V-tail joint. I epoxied a 1 cm strip of woven fiberglass in place directly on the balsa. The V-tail stiffness was immediately improved.

The receiver was wrapped in foam rubber, the antenna pulled through the tail and out the rear opening. I shortened the servo extensions running to the rear servos, soldered the connections and put some heatshrink over the connection. I installed the receiver behind the battery in the tail. It is out of the battery's way in case of a hard landing and also helped with the final balance to get some weight in the tail.

The wings are prepared for the aileron servo, by removing a precut circular hole under the wing. After removing the inner foam core until the top wing covering is reached, the hole is ready to be cut to size. I made the hole an exact fit for the HS-81 servo. The servo extension is run through a tube that is already in place. I cut the extension to size and soldered it directly onto the servo.

Remember to strengthen the servo hole adequately. By removing the material from the wing to fit the servo the wing is weakened. I modified the wings after the first few flight with epoxy and woven fiberglass.

I did not use any servo mounts in the servo bay, but wrapped the servo in Scotch Magic tape and CA glued it in place. CA and Magic tape really works well and the servo never came loose ever. It is removable though, and it is very clear when you eventually have to remove the servo, that the CA bond is a strong one. Make sure that according to the instructions the servo horn is slightly towards the front of the wing in the 0 position. It helps in setting up the aileron differential.

Against the suggestions in many reviews I used the supplied aileron horns. They are the exact size and shape that is required. They were epoxied in place after preparing the aileron by drilling 3 holes in the correct places. I inspect them regularly, and they haven't shown any signs of coming loose.

Use Scotch Magic tape to secure the supplied servo covers over the aileron servos. The covers are easily cut to size.

Finally the Filip was ready for the first test flight. I fully charged both my 8 cell batteries as a show of blind faith. The new NiCads required an initial slow charge of about 15 hours each, so I started well in advance of the planned flight.

Initial flying attributes:

Flying weight

1680g / 59.2oz

Aileron differential 50%
Aileron movement 14mm up / 7mm down
Ruddervator movement 12mm up / 8mm down
Radio mixes V-tail, aileron differential, spoilers (ailerons both up 19mm) & -6% elevators, +15% rudder with ailerons
Center of gravity vement

The first flight was very nerve wrecking (as I suppose many first ones are!). After doing the preflight check about 5 times, the Filip was as ready as it could be. I had an idea how powerful the AXI motor with the Aeronaut blades should be in flight, after reading articles and balancing the prop at home.

It turned out I had no idea!

Deciding not to take any chances, I opened the throttle to 100% and launched to Filip with a strong throw at a slightly upwards angle. It climbed cleanly without hesitation at the shallow angle of the launch. I pulled back very slightly on the elevator, and the angle of ascent increased without faltering. I was totally amazed at the power of the climb. (Subsequent flights showed that almost vertical climbs can be achieved when the battery is still fresh).

After about a minute of climbing at the same angle, with only small adjustments to keep the wings level, the Filip was incredibly high. I leveled off and throttled back to zero power. As soon as I started the first test maneuvers, it became very apparent that the Filip was extremely nimble but true in flight. The 'Sport' version is very precise and the aileron response is immediate and predictable.

During the landing approach the spoilers proved invaluable. The Filip just keep on flying when you get close to the ground, so using the ailerons as spoilers help in bleeding off energy, without running the risk of stalling the aircraft.

All flights so far have been very enjoyable. It behaves very well in a variety of weather and wind conditions. Flight times of 20-45 minutes are easily attainable. It is a plane I can very easily recommend!

Lastly, spare a thought for my wife who had to endure about a week of this mess on the dining table!

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