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CMPro provides good quality RC models. The Kunlun is no exception. It comes with an excellent clear coated fiberglass fuselage, and covered balsa wings and elevator. The fuselage has ample room for the necessary equipment. To allow for efficient cooling, it has several air-intakes and outlets.
First Impressions
CMPro Kunlun Review
Center of Gravity
The fuselage is extremely tail heavy and cannot be balanced with just the motor and a battery. I opted for a heavier and stronger motor and a large capacity battery, but the Kunlun was still very tail heavy. The Kunlun is already heavy as it is, so I didn’t want to increase the weight even further by adding lead in the nose.
The only option left is to lighten the tail. I’m a fan of v-tailed gliders as in the traditional configuration the elevator is easily damaged on landing. So, out came the hacksaw and off came the fiberglass rudder. The cut was an extension of the surface where the aileron was supposed to be glued to. I could then shorten the tail, leaving enough room for the v-tail.
A v-tail should have the surface of the traditional elevator and rudder combined. But, the elevator on the Kunlun is large enough to be cut in half and form a v-tail. The v-tail is now in the position where the rudder once was.
This had the effect that the center of gravity (CG) moved a considerable distance forward. So much so, that I could move the battery backwards underneath to a position where the CG is supposed to be. In hindsight, I could now have installed a smaller and lighter motor and battery. Nevertheless, the total weight after the modification was 1180g/41.62 OZ/ 2.6 pounds, less than the weight specified by the manufacturer.
Modifications
Launch
My first surprise was the Turnigy brushless motor. It was so quiet that I first thought that the engine isn’t revving at its maximum – but it did.
The hand launch is uneventful and the Kunlun climbed out at approximately 60 degrees. My second surprise was how well-behaved the Kunlun reacted to the controls. Nevertheless, take it easy on the aileron as it can become quite agile and, perhaps, out of control if you have a nervous thumb. A beginner should reduce the travel of all control surfaces: aileron, rudder, and elevator.
Soaring
The Kunlun had to conquer a gusty and stiff breeze of between 30 to 40 km/h (17 to 22 kts). It did this with ease. Did I mention that I flew on a slope? Now I have. The wind came from the right direction – perpendicular to the slope, and, despite its weight, the Kunlun could gain and maintain height without engine support.
I mentioned earlier that I wasn’t confident in the strength of the wings, so I did not subject it to rigorous maneuvers and aerobatics. While the Kunlun is, without doubt, capable of basic aerobatics, I’m not keen to experiment with more demanding exercises.
I’m quite content with this, as I get my enjoyment out of peacefully and quietly soaring like the eagles, so to speak. The Kunlun is not a floater as it is too heavy for soaring in light updrafts. But, in good conditions, you can enjoy an extended flight.
During this flight, I have not tested how long the battery will last with the engine running. I won’t do this, as I always need something left in the “tank” to bring the glider home, if necessary.
Landing
Before the flight I expressed my concern to a fellow pilot about possible landing difficulties. The slope has a small and bumpy landing field on the lee side and is subject to strong turbulence. Also, I expected the fairly heavy Kunlun to land at a moderately high speed. My concerns were realised. While the Kunlun didn’t sustain any damage, the landing was rough.
Conclusion
The Kunlun is excellent for some sports flying and soaring in ideal conditions. Overall the Kunlun is well-mannered, but is, nevertheless, not suitable for the beginner. For the conditions on the slope I’m flying, I intend to install some flaps to shorten the landing distance. This is not necessary if you have ample room and a good landing field.
First Flight
- Wingspan: 2000mm
- Length: 1050mm
- Weight: 1.25~1.35 kg (1.18kg/41.62 OZ/ 2.6 pounds after modifications)
- Wing Loading: 42~45 dm/2 (39.6 dm/2 after modifications)
- Airfoil: RG-15 Modify
- Wing Area: 30 dm/2
CMPro Kunlun Data
Wing Modifications
I did not have much confidence in supplied short steel joiner and replaced it with a longer carbon fiber tube.
The steel bolts for mounting the wings to the fuselage are small and probably won’t withstand a hard landing. I replaced the supplied bolts with slightly larger nylon bolts.
CMPro uses the cover film as aileron hinge. Unfortunately, the iron-on film is very tight and restricts the movement of the ailerons. I cut off the ailerons and used reinforced tape as hinge. Now the ailerons move freely, saving battery power and reduce the load on the servos.
Transmitter
HiTech Laser 4
Receiver
HobbyKing, Corona Synthesized Receiver 4Ch 36Mhz (v2)
Servos for aileron and v-tail
HobbyKing HXT900 9g / 1.6kg / .12sec Micro Servo
Electric motor
HobbyKing, Turnigy, TR 35-36C 1100kv Brushless Outrunner
Equipment
Battery
HobbyKing, Turnigy 2650mAh 3S 20C Lipo Pack
Folding propeller
HobbyKing, TGS 11x8F precision folding propeller
Spinner
HobbyKing, FS45-4.0, Folding Prop Spinner 45mm / 4.0mm shaft
Electronic Speed Controller (ESC)
HobbyKing, ESCH40A, TowerPro H40A Brushless Speed Controller
