Sikorsky X2 Technology

On 15th September 2010 Sikorsky's X2 Demonstrator broke the unofficial speed record for a helicopter.  The Demonstrator flew at a true air speed of 250 knots (460 km/h) in level flight.  It even reached 260 knots (480 km/h) in a shallow dive during the 1 hour flight.  Piloted by Sikorsky's Director of Flight Operations and Chief Pilot Kevin Bredenbeck the milestone flight acheived Sikorsky's design goal of 250 knots.  The current FAI rotorcraft world speed record of 216 knots (398 km/h) is set by a modified Westland Lynx in 1986.

Sikorsky's X2 Tecnnology incorporates several new technologies.  They include an integrated Fly-by-Wire system that allows the engine/rotor/propulsor system to operate efficiently with full control of rotor rpm throughout the flight envelope, high lift-to-drag rigid blades, low drag hub fairings, and Active Vibration Control.

Hopefully we would be seeing this new technology incorporated in RC Helicopters soon.

Schubeler DS-94-DIA HST

Schubeler's carbon composite EDF with a 12-blade 128 mm axial compressor wheel driven by an brushless inrunner motor heralds a revolution for EDF's.  Electric ducted fan enthusiasts will love the 74db(A) jetstream like noise from the exhausts at full throttle.  It might even convert diehard fans of turbine engines to go electric.  The EDF will cost just a fraction of the turbines, minus the complexity and associated headaches.

The DS-94 has a fan swept area of 94 cm² and 10 kg of thrust making it one of the most powerful EDFs on the market. Powered by a high torque, Schubeler designed DSM 6740 motor fitted with 12 carbon stators with 220ºC heat resistant windings and magnets.  The 67 mm diameter x 40 mm motor is suspended from the shroud with 4 handmade carbon composite junctions that allows the wires from the 3 motor phases to pass through.  This integrated design feature allows unrestricted airflow to the motor without the use of seperate power robbing cooling fans.

Speed ratios used on the design of the 12-blade axial compressor wheel are similar to the ratios of a full scale turbofan. Besides higher efficiency, it has resulted in a perfect optical scale appearence and boasts a sound which can only be compared to full scale jet engines.  This impressive 1.4 kg monster will need juice from 14s high discharge Lipos to run efficiently. 

Videos: F20 Tigershark fitted with Schubeler DS-94-HST

PVC Control Horns

Control horns made from PVC are very light and robust.  They can withstand many hours of flight with no degradation in performance.  Best of all they are extremely cheap to make,  all it requires is a few minutes of your time.

Electrical conduits or trunkings are a good source of inexpensive PVC.  It is available from most hardware or electrical supply shops.  It is normally sold in 6 foot lengths in a variety of widths and thickness.  Generally the thickness of the PVC varies proportionately with the width of the conduit.  I use 2 inch PVC conduit which is 1.5mm thick, ideal for foamies.

All you have to do is design your control horn preferably using CAD software.  Once you are satisfied with your design, print them onto stickers.  Stick them onto a pre-cut length of PVC conduit.  Drill the linkage mounting hole together with any lightening holes.  Roughly trim the outline with a pair of scissors and file them into the required shape. And voila you have a custom made control horn.

CAD drawing showing linkage mounting and lightening holes

Completed 1.5mm thick PVC Control Horn

Publish Post