MS Composit series Micro Helicopter Mods
The modifications below are very minor in nature and are intended to make the modeling experience more enjoyable by adding performance and convenience. Often during a repair the orange plastic spacer in the tail rotor gearbox becomes damaged. The common ball point pen reservoir serves as the ideal replacement spacer.
Due to the tiny size of the micro helicopter we are stuck with a long antenna wire. This wire can easily be tangled in the rotor or mechanics if left dangling. The antenna should never be cut since this affects receiver/antenna efficiency. The base loaded antenna serves as a viable alternative but adds cost and weight to the model. Inside the base loaded antenna is a coil of wire, which duplicates the antenna length. Rapping the antenna around the skids or balling it up in an untidy mess will affect reception. A lesser evil is to carefully coil the antenna around the skid without overlap leaving enough wire to extend towards the tail fin. While not a perfect solution it does work effectively enough for the distances the micro flys away from the modeler. Fuel tubing is used over the skids to raise the wire off the ground and prevent the insulation from chafing. The antenna coil can be retained with scotch tape or something similar.
Looking at the picture above you can see a small radio tray is added to help tidy up the electronics. If you look carefully you’ll notice the gyro is soft mounted to a spare servo mount glued to the main frame area. The common floppy disk may be torn apart and two rectangles cut out of the case using scissors, these two pieces are then glued together with CA for stiffness and installed in place of the stock servo mount. Since the floppy casing is black it looks like it belongs on the helicopter. Velcro rap holds the brushless controller and receiver neatly and securely in position.
The Hornet CP and hornet CPX use a non-adjustable tail rotor pitch control rod. By making the rod adjustable on one end, fine tuning this linkage becomes a very easy matter. A side benefit is that in order to fit the threaded coupler a thicker control rod is needed which adds a welcome rigidity to the control system. The Hornet-II is supplied with the thicker control rod so it already enjoys a better tail rotor pitch control. Finding carbon rod material is easy. I used the flybar from a Cupid micro helicopter and sanded the ends to fit the coupler and the stock rear clevis.
The belcrank on the tail rotor gearbox sometimes rubs on the gearbox. While minor in nature it is still one area that might be tweaked. All the belcrank needs is a thin spacer to move it lower. Since this increases the stack-up length the retaining ring has no place to grip. The pivot area on the belcrank can be shortened by the thickness of the spacer to correct this potential issue. If you are good with an X-acto knife you may slice the belcrank washer off the belcrank in one step as I did in the picture, or you could use a thinner washer instead.
After installing the newer control rod, using the newer steel T/R output shaft and tweaking the system we have found the suggested 30mm measurement in the Hornet CP/CPX manuals to be no longer valid. A measurement of 20-25mm now holds the tail stationary in the hover using the MS supplied gyro and servo. We found this to also be the case with the Hornet-II . Keep in mind that this dimension will vary depending how far the tailrotor shaft is installed into the supporting bearings as this moves the tail hub closer or further away from the gearbox. Setting the neutral on the linkage is easy if you use the lower mold flashing mark. Note how the belcrank arm is in line with the red circle’s edge at the correct hovering tail rotor blade pitch angle.The flashing circle is colored red for clarity and is similar in appearance to the non painted aft flashing circle.
The GWS 6 channel receiver fits well and makes keeping things tidy easy. It works very well fitting the micro application perfectly. We soft mounted it for vibration isolation. Common mounting tape may be used to secure wiring to the servos and to attach the brushless MS speed controller to the front radio tray. The brushless system offers governor like performance, better electrical efficency, less noise and best of all no brushes to wear or replace. LI-Poly battery technology keeps the weight down and energy storage high. This also allows higher voltage and higher electrical current which equates to an increase in the 3-D envelope.
The MS-044 HH gyro takes the Hornet-II up several notches in performance allowing full aerobatic capabilities such as inverted hovering, backwards flight upright or inverted. The machine does so much more when tweaked out with the higher grade MS components.
It has been suggested that the micro helicopter need only be fixed pitch and that collective control should be reserved for the bigger model helicopters capable of full aerobatics. I think the Hornet-II picture below is worth a thousand words and pretty much disproves this theory, which in all fairness may have been true in the past.