FMS Mini J-3

From EFlightWiki
Jump to: navigation, search
Overall view of the FMS Mini J-3
Head-on view showing the simulated engine, cabin glazing and pilot figure

The FMS Mini J-3 is an inexpensive, four-channel, RTF scale model of the Piper J-3 Cub sold through low-cost internet retailers such as HobbyKing and Nitroplanes. It is also available as an ARF and as a receiver-ready RTF.

The model is manufactured by Shenzhen Famous Electronic Tech Co., Ltd. of Shenzhen City, China and is marketed under varying brand names, depending on the retailer. HobbyKing markets their version as the HobbyKing J-3 RTF with the onboard electrics labeled with the HobbyKing brand while Nitroplanes markets theirs as the Airfield 40" J3 Piper Cub.

Construction is of EPO foam with plastic details including an interior tub and pilot figure. Other scale details include highly detailed simulated cylinder heads, a spring-loaded tailwheel similar to that on the prototype and two-piece, prototypically correct wing struts. The RTF version comes with a four-channel 2.4GHz radio system with four 9g analog servos, brushless outrunner motor and a 1000mAh three-cell lithium polymer battery with DC balancing charger.

Though well made for such an inexpensive model, there are some issues involving the low cost. Chief among these are the plastic hubs used to retain the wheels and tires. The hubs are easily broken, they do not allow the wheels to spin freely and are screwed onto the landing gear. Since the threads are cut in the same direction, any binding will cause the left wheel to unscrew itself during takeoff or landing if the hubs are not modified or the wheels and tires replaced with universal, off-the-shelf units retained by standard wheel retainers.

Propeller balance may be a problem with certain models. The propeller slides directly onto the motor shaft and is similar to those made by GWS, although it is considerably heavier and stiffer.

An E-flite 3mm prop adapter with collet (EFLM1922) and an APC 9x6SF slow flyer composite propeller (LP 09060SF) work perfectly and exhibit no vibration, but extend farther from the front of the cowl due to the length of the motor shaft. The shaft may be trimmed if desired. Though not necessary to do so, trimming the shaft will reduce the risk of it being bent should the propeller contact the ground.

Flight characteristics

The Mini J-3's 1300Kv motor and 9x6.8 propeller (incorrectly identified on the hub as "6.8x9") are capable of speeds far exceeding scale, making it unsuitable for small field flying. Flight characteristics are relatively gentle, although the factory aileron setting is somewhat "twitchy" and over-responsive. Despite the scale wing, which often translates into heavy wing loading on a model, the model flies well at scale speeds. The extra power allows for loops, but the small scale ailerons do not allow the Mini J-3 to roll quickly. It will, however, fly inverted and is capable of basic aerobatics.

Landings are simple, but some power must be maintained to prevent a tip stall prior to touchdown, even though the model glides well overall.

It is suitable for intermediate to advanced fliers age 14 and up.

Specifications

  • Wingspan: 40.5" (1030mm)
  • Wing area: 230 in² (15dm²)
  • Weight: 22 oz. (625g)
  • Length: 29.5" (750mm)
  • Wing loading: 1.5 oz/ft² (41.5g/dm²)
  • Construction: Expanded polyolefin
  • Servos: 9g analog micro
  • Transmitter: Four-channel 2.4GHz park flyer with servo reversing, delta wing mixing and selectable Mode 1/Mode 2 operation
  • Receiver: Four-channel 2.4GHz limited-range
  • Battery: 1000mAh 20-30C 3S lithium polymer with JST power connector and JST-XH balancing plug; brand varies by distributor
  • Motor: 1300Kv brushless outrunner
  • ESC: 20A brushless
  • Propeller: FMS brand composite, diameter/pitch rated at "8.6x9," actual pitch is likely 9x6.8
  • Typical flight duration: Six minutes
  • Minimum skill level: Intermediate/advanced; listed as a beginner model by HobbyKing
  • Manufacturer: Shenzhen Famous Electronic Tech Co., Ltd., 4/F, Building 5, The 3rd Industrial Zone, Tangtou Shiyan Town, Bao'an District, Shenzhen City, China 518105
  • Price (USD): $119.99 from HobbyKing, $159.99 from Nitroplanes, $67.79 in ARF form from HobbyKing

External links