UMX™ Timber™ by E-flite®

21 Apr 20 - Ready to test fly

No of launches / Time 0 0 hr 0 mins Time only recorded for time flying on floats
Wingspan 27.6 " 70 cm    
Wing Area 119 in2 7.7 dm2    
Flying Weight 4.6 oz 130 g    
Wing Loading 5.6 oz / ft2 16.9 g/dm2
Wing Cube Loading 6.1 - Trainer  
Motor E-flite 180BL 3000kV pre-installed
Propeller 5" x 2.75" 2-blade pre-installed
Batteries 2S E-flite 400 mAh LiPo (increased from the standard 280 mAh for float plane use)
Speed Controller Spektrum A6420L 6-ch ultra-micro with AS3X, SAFE and brushless ESC built-in
Servos Ailerons - 2 x Specktrum A2030 Ultra-Micro Analog 2.3g Linear Long Throw Offset Servo
Elevator - built-in to receiver
Rudder & water rudder - built-in to receiver
Static motor parameters  Untested
Flight performance Untested

21 Apr 20 - I bought the float set for the UMX Timber some time ago but wasn't happy with the idea of no water rudder.  I decided that I could 3D print a lightweight water rudder assembly to be glued to the rear of one float.  I designed and printed the water rudder, which incorporates a metal spring (ex-floppy disk shutter) to keep the blade down and tiny BA bolts to attache the steering arm and form the steering and blade pivots.  The total weight of the assembly was less than 2g, plus a little more for the control rigging.  To connect to the 'air' rudder I added a second control arm to the rudder so pull-pull control could be used with small monofilament fishing line plus a couple of springs and Z links.  The total weight gain is 15g from the wheeled version.

For those unfamiliar the coin in the 4th photograph is a UK 5 pence piece, which is 18 mm (0.7") in diameter

The UMX Timber can be swapped from land to water operations in only a couple of minutes; the tailwheel is left fitted when on floats as it's taped in place and the wire is trapped under the original control horn (much easier to leave it there).  Due to this the model is a more tail-heavy so a 400 mAh battery is fitted in place of the original battery 280 mAh battery, which can continue to be used for land operations.

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