Well it was supposed to be a rolling harrier...but it ended up in a hover, I really need to practice that a little more!
|Wing Area:||203 sq. in.|
|Wing Loading:||3.7 oz/sq. ft.|
|Servos:||3 submicro 6g servos|
|Battery:||Tanic 2s 520mah LiPo|
|Motor:||LensRC CD-ROM motor& Westport CD-ROM motor|
|Manufacturer:||Model Airplane Engineering|
|Available From:||Your favorite hobby shop, or online at Model Airplane Engineering, email: MAEngineering@bellsouth.net|
The Slick is an aerobatic park flyer, designed for maximum fun in minimal area. It performs great on the new generation of inexpensive CD-ROM motors, and two cell lithium polymer batteries. The kit is extremely quick building and is attractively priced at only $37.95.
The great thing about Model Airplane Engineering (M-A-E) is that you can get everything you need from them. They supply the kit, motors, mounts, servos, batteries, speed controls, propellers etc. I really liked being able to get everything required to complete the kit from one convenient, friendly dealer!
The slick is a very quick building kit. The instructions indicated that it could be built in about two hours. That was definitely an optimistic goal for me! I am a slow builder. But, even taking my time, it was finished in two evenings. The instructions were easy to follow, and very well thought out. I spent the first evening planning out the coloring scheme and applying it. The second evening, the assembly of the pieces was started and completed. The Slick even came with nice vinyl graphics already applied!
The fuselage arrived laser cut from six millimeter depron. It didn't require or use any additional bracing. The slots for the servos, wing, stabilizer, and motor mount stick were laser cut, so they were an extremely good fit. The motor mount stick was glued into the fuselage using foam safe CA to ensure a stiff tight bond. The final step in completing the fuselage assembly was hinging the rudder to the fuselage using clear packing tape.
The hardest part about assembling the wing was deciding on a color scheme that helped to differentiate between the top and the bottom. I used Sharpie brand permanent magic markers to color it. Using UHU Creativ glue for foam, the flat carbon fiber spars were attached to the leading edge of the wing, and at the hinge line. The Creativ glue is a contact cement, so glue was spread evenly on the carbon fiber strip as well as the depron. After both surfaces were dry then they were pressed together to form a really strong joint. There was a side benefit of having a carbon fiber spar on the leading edge. It later took a lot of abuse, and protected the depron from any damage from landing or flying into things (don't ask how I know about that). The stabilizer was assembled in the same manner, with one carbon spar glued to the hinge-line. The hinge-lines on the ailerons, the elevator, and rudder were hand cut by the manufacturer with a generous bevel that allowed lots of control movement, perfect for extreme aerobatics. After the spars were added, the wing was glued into the fuselage slot. Using foam safe CA and a little baking soda the wing was glued in with a small fillet.
The contact cement did not work as well for joining the wing to the fuselage because the glue could flex a small amount and that flexibility could affect the flight performance. Included in the kit were some very nice, laser cut plywood control horns. The aileron horns had a very wide base that was glued to the root of the aileron that made them very stiff. The ailerons were then hinged with packing tape, and that completed the wing assembly.
The fuselage had pre-cut holes that fit most common sub micro servos in the 6 gram range. I used GWS pico servos for the rudder and elevator and used a slightly larger hitec HS-55 for the ailerons. The cut out for the aileron servo had to be enlarged slightly to fit the hitec servo. I used a GWS R4P with an azarr micro lite antenna to keep weight to a minimum, and to get rid of the long receiver antenna wire.
To complete the radio equipment, I used a Castle Creations Phoenix 10 brushless speed control. The phoenix 10 is the perfect choice for the new cd-rom motors that are becoming so popular. With all the built in programmability, I could experiment with different timing options, brake settings, low voltage cut offs, over current protection, soft start up for fragile gearboxes, motor cut off settings, and even a governor mode (I can see a variable pitch prop set-up, utilizing the governor mode in the Phoenix 10, on one of these cd-rom motors in my future). This is one incredibly versatile speed control that has worked very well for me!
For the motor, I used both a LensRC, and a Westport cd-rom style motor, mounted with one of MAE's laser cut plywood mounts. The mounts were a very tight fit and held the motor very well. The motor mount then slid over the mounting stick glued into the fuselage, and was held in place with a drop of CA. NOTE: MAE suggests a method for screwing the mount to the motor stick, making the motor installation portable.
After the electronics were mounted, the control horns and push rods were the last thing to install. The control horns supplied in the kit were very stiff laser cut plywood, with a ply base to increase the bonding area, and to distribute the load over a larger area. They looked and worked great.
The last thing to do was to check the cg location and control throws. The instructions indicated the CG at two to three inches behind the wings leading edge. I started out in the middle of the recommended range. This was easily achieved by locating the battery under the leading edge of the wing and attaching with the supplied hook and loop material.
Control throws were set up as recommended, the amount of exponential indicated is the percent I used:
|Control Throws||(directions are each way)|
|Surface||Low rate||High rate|
|Elevator:||1" 35% expo||2" 45% expo|
|Ailerons:||1.25" 25% expo||2.25" 35% expo|
|Rudder:||1.5" 20% expo||2.5" 30% expo|
The Slick does not come with landing gear, so hand launching is required. I prefer to hold the canopy in my left hand, advance the throttle about half way, point the nose up at a 60 degree angle and let go. With a little up elevator and a little power I can easily pull up into a hover, or it will settle into a steady climb flying away. Another method to launch the Slick is to hold it by the fuselage under the wing and launch it javelin style with a little throttle applied, and it easily flies away. Either method is simple.
Landings are not a problem either. I usually had so much fun flying that I would fly until the low voltage cut off would cut the motor off. The Phoenix 10 has a programmable low voltage cut-off that can be set for the type of battery in use. For the two cell tanic packs I used a 6 volt cut off. The tanic packs perform so well in this plane, that I could barely notice a drop in performance right up until the low voltage circuit would cut the motor off. The Slick doesn't exactly glide very well, but that's not what it was intended for. When the motor cut off, I was generally close to the ground so I would level the wings and let it settle in and pull full up elevator before it touched down. This method resulted in a landing with almost no forward speed at all. By using a little throttle I could fly it to the ground and cut the throttle just before touching down for a more conventional landing. The brake function on the Phoenix 10 is adjustable. It can be turned off to allow the propeller to windmill, or several other settings. I chose to have a hard brake with a delay. Using this option ensures that the prop stops rotating. This reduced drag, and helped with the glide. The delay helped in performing maneuvers like stall turns that require bringing the throttle back to idle momentarily. It allowed the propeller to windmill momentarily for a smooth throttle up. Another fun way to land the Slick is to climb fairly high, cut the throttle then push down elevator into a dive. I would let it fall ten feet or so then pull full up into an elevator. With a slightly aft CG location the Slick would slowly fall while it stayed perfectly horizontal. It descended slowly enough that I could land it this way, and it definitely looked neat! MAE also offers an optional landing gear kit if you prefer to have the option to take off from the ground.
Aerobatics, in particular "3D" style aerobatics, are what the Slick was designed for. It only took a few minutes to get used to the flight characteristics of the Slick and then it was time to find out what it was capable of doing. The Slick has very good performance with the inexpensive CD-ROM type motors. Mine as equipped has about a 2:1 thrust-to-weight ratio and that provides excellent vertical performance. The Slick does all the basic aerobatics like loops, rolls, knife edge flight, and stall turns very well.
The best thing about it, is how little area you need for flying. The Slick made my back yard seem huge. It is a great airplane for someone with a limited flying area, that wants to learn 3D style aerobatics. Knife edge flight is very slow and predictable with the Slick. Even knife edge loops are possible (more details below). The location of the battery, and its weight, has a noticeable effect on its performance in knife edge. Using a light weight battery like the Tanic 2s 520mah pack and placing it as close to the center line of the wing as possible helped to eliminate any coupling. Harriers right side up were flown very easily with little or no wing rock, with a slightly aft CG setting. Inverted harriers were not quite as stable. To make inverted harriers easier, the battery can be placed on top of the wing.
The Slick is a great plane to learn to hover with. Having plenty of power, and good control authority makes learning hovering and torque rolling much easier for the beginner. The Slick even does good rolling harriers, much better than my flying skills allow. I can get a few harrier rolls before I would give a wrong input, or too much of something. With the cg located at the aft position, it took very little rudder and elevator inputs to keep the nose up when rolling. It was pretty easy for me to input too much elevator when inverted, and it would push right up into a hover. It wasn't exactly what I planned, but it looked good!
The Slick was able to do just about everything I could think of. Blenders, knife edge loops, walls, elevators, parachutes, you name it and it could do them if your thumbs are up to it. In maneuvers like knife edge loops and blenders where the airplane is under a lot of stress, you could tell at times that the airframe was flexing somewhat. For example, when starting a blender and rolling while diving vertically, the roll rate would slow down as the speed increased. During knife edge loops, the Slick was a little difficult to pull out on the last quarter of the loop. Read on, because these minor issues were soon to be addressed!
After several weeks of flying the Slick, the weather here turned colder. The first time I took the Slick out on a cold day below 50 degrees, I noticed that the depron wing seemed to have a little bit of a warp in it that I hadn't seen before. Not thinking much of it, I flew it anyway. The results weren't impressive. The wing was developing a bad twist that made flying difficult. The next day I received an email from Randy Roman at Model Airplane Engineering, asking me if I had experienced any problems with the wing warping in cold weather. He had experienced the same problem, and was already on top of the situation, working on improvements to the Slick to eliminate the cold weather induced warp. Instead of ignoring the problem and continuing selling the kit as is, M-A-E was already contacting owners of the Slick to determine the extent of the issue and working on the solution. That is excellent product support! I tried to eliminate the warping problem by adding kevlar flying wires on the top and bottom of the wing. This helped the warping problem tremendously, but as the temperature dropped, the depron apparently would contract and the flying wires would get looser.
M-A-E came up with an even better solution to the problem. New Slick kits are now being shipped with additional carbon fiber rods that attach to the carbon fiber spars on the wing leading edge and hinge line. These rods are glued to the spar then are attached to the bottom of the fuselage with plywood reinforcements. They add very little weight to the Slick, and totally eliminate the cold weather wing warp.
I found that the flying wires helped to improve the already good flying characteristics of the Slick. Previously, the faster the Slick would fly, the slower the roll rate would get. Now with the flying wires attached it rolls much faster, and more consistently. It has also helped in other areas like snap rolls. Overall the Slick has a more responsive feel to it with the additional bracing. I also found that the fuselage was flexing too much right behind the wing and that was making rudder inputs a little unpredictable. I added two strips of carbon rod where the wing glues to the fuselage to make the fuselage stiffer. This has helped with knife edge performance, and has made it more predictable. MAE now includes these parts to brace the wing and the fuselage.
I used the Wesport and LensRC CD-ROM outrunner motors to fly the Slick. I experimented with both to find which one best suited my flying style. After flying both extensively, I still don't know which one I prefer. They both perform very well, and both have their strong points. I started out with the Westport motor. The Westport motor looks like it may have been happily spinning cd's only a few days earlier. The three hook-up wires going to the motor are the same wire that is used to wrap the stator, so it is very thin. I was concerned that I might fatigue the wires and cause them to break eventually, but never had any problems. I first flew it with a GWS 8x4.3 SF propeller and was very happy with the performance. It climbed vertically very well, not a rocket, but plenty fast enough to suit most fliers. In hovers with that propeller, the tail was effective enough to hold a hover, but it took a little more work. Torque rolls were possible, but the Slick did not want to rotate very fast. This setup makes a good combination for doing a little 3D style flying and more conventional looping and rolling maneuvers. With the 8x4.3 propeller and the Tanic 520mah lipo, I could fly for about 15 minutes. The tanic packs held up to the current draw very well, and had power to spare. I could hardly notice a decrease in performance throughout the 15 minute flight.
The next propeller I tried on the Westport motor was the recommended GWS 9x5 HD. This made a big difference in vertical performance! The Slick went from having good vertical performance, to having great vertical. I hardly ever used full throttle with this propeller, as it wasn't needed. With this larger diameter propeller hovering maneuvers were slightly improved, and the Slick would torque roll better. This combination was one of my favorites for a good compromise in all around performance. The only drawbacks were the shorter run time, and slower throttle response because of the larger propeller. I also experimented with using a tanic 830mah 2s lipo with this setup. Changing to this battery gave an increase in run time. Flights were now over 20 minutes. This battery is slightly heavier than recommended, but the weight was hardly noticeable. The increase in overall power available from it more than offset the additional weight.
After flying the Westport motor for a few weeks, I switched over to the LensRC motor. I really had no reason to change as I was very pleased with the setups I had already tried. The first thing I noticed about the LensRC cd-ROM motor is the appearance. The motor can is painted blue, the motor wires are neatly wrapped and shrink wrapped, it just has the appearance of a high quality motor. The first flights on this motor were with a GWS 10x4.7 propeller installed. The differences in vertical performance were immediately noticeable. The LensRC motor was not climbing as fast as the Wesport motor was. It turns a larger propeller, but at a slower rpm, so it has plenty of thrust but not much speed to accelerate vertically. I noticed the biggest difference in hovering maneuvers with this combination. The larger diameter propeller really helps with hovering and torque rolling. The lower rpm motor obviously has more torque, and the Slick really rotated easily in a torque roll, and the controls were much more responsive. The drawback to this setup is that for normal flying around, more throttle is required to keep speed up, so I ended up having shorter flight times, around 12 minutes. I found that both tanic packs handled the higher current draw very well, but that the 830mah pack was better suited for the higher constant current draw. The next propeller I tried was the GWS 10x6 HD prop. The Slick seemed to perform slightly better in forward flight looping and rolling maneuvers with this prop, and required less throttle to do them. Vertical performance appeared to be better as well. It didn't hover quite as well as the 10x4.7SF, but it was still quite good. I still haven't decided on a favorite. I really like to hover and torque roll with the LensRC motor, and GWS 10x4.7 propeller, but the power available from the Westport motor is very impressive. These readings were taken with an Astro Flight whatt meter:
|Westport Cd-ROM motor|
|Prop Used||Battery Used||Amps||Watts|
|GWS 8x4.3SF||Tanic 2s 520mah||4.3A||29W|
|GWS 8x4.3SF||Tanic 2s 830mah||4.7A||34W|
|GWS 9x5 HD||Tanic 2s 520mah||5.0A||33W|
|GWS 9x5 HD||Tanic 2s 830mah||5.5A||39W|
|LensRC Cd-ROM motor|
|Prop Used||Battery Used||Amps||Watts|
|GWS 10x4.7SF||Tanic 2s 520mah||4.5A||31W|
|GWS 10x4.7SF||Tanic 2s 830mah||5.0A||36W|
|GWS 10x6 HD||Tanic 2s 520mah||4.1A||29W|
|GWS 10x6 HD||Tanic 2s 830mah||4.3A||32W|
I attempted to take some thrust measurements but my results were not very dependable. I found that the Wesport motor had approximately 9-10 ounces of thrust, and the LensRC motor had approximately 8-9 ounces of thrust.
The tanic batteries used for flying and testing the motors have performed very well. Even when the current draw approached their maximum discharge rate of approximately 5 amps, the 520 mah pack performed very well and only got slightly warmer than the ambient temperature. The 830 mah cells definitely are able to provide more power, give longer flight times, and the slight addition of weight was not a problem at all. The "Tanic Taps" are a great feature. After approximately 30 cycles on each battery, I checked the voltage of each individual cell and found the cells to still be perfectly matched. It is great being able to monitor the condition of each individual cell, and being able to balance the pack as needed.
This model is not intended for the beginner pilot. It is meant for the intermediate to advanced pilot that wants to be able to practice 3D Style flying. Its small size and light weight make it a great airplane for flying indoors in rooms the size of a gymnasium or even smaller. Advanced pilots will appreciate the compact size, that enables you to take it just about anywhere to get a 20 minute flight of full 3D fun.
Here are a couple of videos that give you just a little idea of what the Slick is capable of. The first video was shot in my back yard, which is ample room for anything you can think of. The second shorter video shows why the Slick is one airplane you always want to throw in the car. A little rain doesn't have to ruin your day of flying. Its time to bring the Slick out for some fun!
The Slick has been a fun-to-fly, great little small field/indoor flier. It has the capabilities to fly just about any maneuver, and it does them very well. Model Airplane Engineering has been a great company to deal with. They supply all the products needed for this great little plane, and they have excellent product and customer support.
|Jan 08, 2005, 11:40 AM|
Joined Jan 2002
Excellent review, very comprehensive and helpful. Covered everything that anyone could possibly want! Keep up the good work. Reviews such as this will certainly add to the service and reputation that RC Groups provides their members.
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