Knife Racer 1m
Description
The pylon racer is very nicely molded with a strong wing spar and a massive battery compartment, which will allow 4S 2Ahr batteries, or even larger to be fitted with ease. Performance is very good, very straight at high speed, very nice high speed glide, and a reasonable landing speed with the flaps down. The aerodynamic shape is good. The model looks like a scaled up Sergey Sobokin Stinger Speed 400 pylon racer, which indicates a good heritage.
Note the Knife originally had centrally mounted aileron servos and was called Knief, but now has wing mounted servos and a less confusing name. :-)
Some info on RCGoups here.
| Knife Specifications | ||
|---|---|---|
| Wing span | 1.00 m | 39 in |
| Wing area | 9.8 dm2 | 153 sq in |
| Length | 64 cm | 25 in |
| Flying weight from | 550 g | 19.4 oz |
| Wing loading | 56 g/dm | 18.3 oz/sq ft |
| Aspect ratio | 10.2 | |
| Wing airfoil | 7% proprietary | |
| Dihedral (EDA) | 1.3º | |
| Spinner Diameter | 38 mm | |
| Battery compartment | approx 40 x 38 x 170 mm | |
| Centre of Gravity | 42 - 47 mm from wing leading edge | |
| Controls | Elevator, ailerons, throttle | |
| Knife Typical Weights | ||
|---|---|---|
| Wing | 147 g | 5.2 oz |
| Fuselage and fin | 85 g | 3.0 oz |
| Tailplane | 17 g | 0.6 oz |
| Accessories | 17 g | 0.6 oz |
| Total structure | 266 g | 9.4 oz |
| Receiver | 6 g | 0.2 oz |
| Elevator servo | 8 g | 0.3 oz |
| Aileron servos (2) | 16 g | 0.6 oz |
| Speed control | 25 g | 0.9 oz |
| Motor | 74 g | 2.6 oz |
| Prop & spinner | 15 g | 0.5 oz |
| Battery | 140 g | 4.9 oz |
| Flying weight | 550 g | 19.4 oz |
| Recommended Control Throws & Mixes | |
|---|---|
| Elevator | 3 mm up, 3 mm down |
| Ailerons | 4 mm up, 4 mm down |
| Snap Flap | full up elevator -> 1 mm down flap |
| Landing mode | motor off -> 5 mm down flap |
| Recommended Servos | |
|---|---|
| Elevator | KST X08, Blue Bird BMS-A10H, MKS DS75K, MKS DS6100, MKS HV6100, MKS HV6110, Blue Bird BMS-126WV, Blue Bird BMS-127WV |
| Ailerons (2 servos) | KST X08H, MKS DS75K, Blue Bird BMS-A10S, Blue Bird BMS-A10V |
| Recommended Powertrains | |
|---|---|
| 100 mph | Mega 16/15/3, 4.7x4.7 35A ESC, 3S LiPo, 350W |
| 110 mph | Mega 16/15/2, 4.7x4.7 50A ESC, 2S LiPo, 400W |
| 120 mph | Mega 16/15/3, 4.1x4.1, 50A ESC, 4S LiPo, 500W |
| 130 mph | Mega 16/15/2, 4.1x4.1 60A ESC, 3S LiPo, 600W |
| 135 mph | Mega 16/20/2, 4.5x4.5 60A ESC, 4S LiPo, 650W |
Reviews 4
Has been waiting for almost 3 months. Once I got the notification that the plane is back in stock I had order it immediately. The plane itself looks perfectly made and perfect finish. All of the parts you need is included. I also had order the recommended servo from Blue Bird. I still have to start building it and hopefully will maiden soon. Big thanks to Neil for a perfect customer service!
After reading other reviews have gone for a lightweight set up: 2207 2750kv quad motor, 45a Speedix ESC, 4 cell 1100mah lipo and 4.74x4.75 APC prop. Radar gunned at 145mph. Exactly the sort of speed I was looking for without too much outlay. Relatively easy build with lipo up front to achieve stated c of g without additional weight. Be careful with elevator control horn: too short.
All in all very pleased.
Unlike the Voodoo this model takes some time and care to set up but once done the rewards are there; the longer wingspan gives a broad scope of ability; a very light setup can glide off power for a while; launches and landings are very stable and predictable. Initially using a conventional inboard motor plus 38mm spinner I was unable to achieve absolute zero vibration throughout the whole rev range. After some research I decided to try something radically different and installed a Hypetrain 2207 Acro motor outboard of the firewall. Weighing a little over 30g but capable of producing around 2kg thrust, this quad motor is a revelation. With a balanced prop there is zero vibration throughout the whole rev range. Even with a light weight first run setup, speed is excellent, using a 2450Kv motor running a 5.5x4.5 prop. With a 1900Ah 3 cell pack I got around 8 minutes of mixed flying which could have easily been 10 minutes with more climbing and gliding.
