|
|
 |
|
|
 |
|
|
The Complete Conversion guide to a fixed pitch sub micro conversion R/C Heli
|
|
|
 |
|
In this document, we will outline the steps in converting an FP micro heli such as the Feda Hummingbird or Piccolo into a a Midget ( Yes, making your Micro Heli even smaller ). The process is very easy and doesn’t require any sort of special tools besides common hobby ones. The project can be done in a one or two evenings and the best part of it is that you can convert back to the full size micro with purchase of a few new parts. The Sub-Micro can be flown in smaller spaces than it’s micro counterpart and is a bit easier to fly due to the higher head speed.
|
|
|
|
|
|
Take your time with the measurements since small amounts can make large differences in flight characteristics. Please remember that the conversion is the same for any of the FP micro helis that have a motor driven tail rotor. Lets get started, here is what we have before we get started. First a few tips about cutting the parts in this project, two tools were used primarily, a sharp set of fabric sheers or scissors and an X-acto knife with a No. 11 blade. A Dremel tool can be used if one is available but is not need. A sanding block will be needed to final shape the parts.
|
|
|
Take great care in making the measurements correctly and cutting accurately. A great method for making the cuts is to measure and mark the part to be cut with a pencil, then using your X-acto knife, score the line and continue to score the mark until a cut is made, this way, the cut will be almost if not perfect if measured correctly. When using the sheers, make sure you cut a little outside the line to allow some room for the error.
|
|
Landing Gear - First we start by cutting the stock landing struts down to about 60mm, if you want a little higher stance, cut them down to 65mm. Make sure you cut all 4 landing gear struts the same length. Don’t try to make the cut the first time, score the rod and then roll the knife over it several times until it’s cut, otherwise, the rod will split and splinter.
|
|
Tail Boom - Next we cut the stock boom down from 32cm to 24cm. If you are using an X-Acto knife, roll it over the boom several times and don’t press too hard so that you don’t crush the tube.
TailSkid - Next, we cut the tailskid down to 65mm or to a height that keeps the tail rotor from striking the ground. The tailskid can be cut while it’s still inserted in the tail hub, just measure from the bottom of the hub to the end of the tailskid
|
|
Tail Brace - If your heli was equipped with a tail brace, then that will have to be cut down as well, we took off about 40mm on our prototype, the best thing to do is to put it on the heli to see how much needs to be cut, but anything in the 40-60mm range should work, as long as the tail rotor doesn’t strike the horizontal fin. Make sure you cut both of the support struts the same length.
|
|
 |
|
Tail Fins - If you have tail fins, then you may want to cut them as well to make them look better. You can choose to leave them off if you don’t want to cut them down. Cut 10mm from each tip of the horizontal and vertical. Then cut 5mm from the front sides of the horizontal. Cut 5mm from the front and back of the vertical. Since each set of fins can vary, you may want to make smaller cuts and custom fit yours on there. After the cuts are done, this is what it should look like. Attached them back to the finished heli as you would with an uncut version.
|
|
|
 |
|
|
Paddles - In the next few steps, we make some cuts on the main rotor blades, fly paddles and flybar. Take your time to ensure you’ve made the right measurements and cuts to ensure you have a successful flying machine. Remember to always measure twice and cut once, you can always cut more but you can’t add back! Lets start by cutting the paddles, we cut 2mm from the front, 2mm from the rear and 9mm from the outermost tip as shown in the picture. The bottom paddle is the one that’s been cut and edges rounded with a sanding block.
|
|
|
 |
|
|
Flybar - Next, we cut the flybar down to 145mm, you can try to fly it with a less of a cut and then go from there but that’s what’s worked great for us.
|
|
|
|
|
 |
|
|
Main Blades - In the next step we cut the main blades, take great care in your measurements so that you don’t take off too much material. We start by taking 65mm from each blade tip for a more floaty type of feel, if you want a little more head speed, then cut 67mm off each tip. About 2mm can be taken off the trailing edge as well for more headspeed. We’d recommend that you start with the 65mm cut, test fly and work from there as you can always cut more but can’t put back material.
Here are both blades cut with edges rounded, balanced and ready to be mounted back on the head assembly.
|
|
|
 |
|
In the final few steps, we just make sure to balance the tail blades, main blades, flybar and paddles attached to the head. Once everything looks like it’s balanced, we put everything back together. Check for CG by moving each blade to the front and back of the heli and balancing by the flybar. The heli should balance level or with a slight nose low position with the pack in place and canopy attached. Move the pack forward or backwards until proper balance is achieved. You can use the stock canopy and just trim it to your liking or use the MS Composite Hornet canopy as we did and trim it down to fit. For a more scale look, the MS Hughes canopy works great as well.
|
|
 |
|
Finally, we are ready for the test flight. Make sure the pack is fully charged. Take a look over the whole swash assembly, tail motor and rotor, make sure the servos are moving in the right direction. Once satisfied, put on your training gear for the test flight. You can also test run the heli in your hand, but please take great care and make sure you have eye protection. The heli should feel stable and very solid due to the increased headspeed. From here, you can make minor cuts as needed to customize to your own flying habits.
We hope you enjoy the conversion as much as we did, customize your Sub-Micro to your likings by adding a brushless motor, different canopy and carbon fins. Happy flying!
|
|
 |
|
The sub Micro Heli fly’s great and it is very stable. The smaller size makes it ideal for indoor flying even in smaller rooms.
The conversion is straight forward and no special parts are necessary.
The article explained how to execute the conversion on both the Piccolo as well as the Hummingbird and although we like flying these Helis with the CNC mods, these upgrades are not required to complete the Sub Micro conversion procedure - Happy Flying
|
|
|
|
