Chapter 8. Helicopter Construction

Table of Contents

8.1. General tips for all helicopters

8.1. General tips for all helicopters


For specific helicopter construction tips see Section 28.2.3, “Construction tips for specific helicopters”.

8.1.1. Building

Do not rush building the helicopter. Take your time and be very careful with everything, and make sure everything moves smoothly. If all moving linkages do not move smoothly, then the helicopter may have vibration problems later which will make hovering very difficult. A few extra hours spent making sure linkages move smoothly will pay off later when you shorten your hovering learning time by a few months.

8.1.2. Threadlock

Only use threadlock on metal-to-metal areas. Do not use threadlock on:

  • metal-to-plastic areas

  • plastic-to-plastic areas

  • setscrews (will become nearly impossible to remove)

  • bearings

  • Nylon locking nuts. The nylon insert will prevent the nut from turning and therefore loctite is not necessary.

Blue threadlock is temporary, for stuff which may require disassembly later (after a crash, etc). Red threadlock is permanent, for stuff which will never be disassembled.


  • Blue threadlock for the tail blade grip screw

  • Red threadlock for the swashplate ball screws

To disassemble loctited parts, apply heat of over 100C/212F. This should soften the loctite enough to remove the parts.

If you use threadlock on a setscrew, it will not prevent the setscrew from slipping on the shaft. It will only make the setscrew impossible to remove later.

8.1.3. Gear lubrication

Do not lubricate any exposed gears. This will only make the gears sticky and pick up grit, which will cause premature gear wear. It is okay to grease gears in enclosed gearboxes such as the Corona tail gears. When using lubrication, be sure to use a grease which will not soften plastic, such as a silicon or lithium grease. Tri-flow synthetic grease (available at most bike shops) also works very well.

8.1.4. Frame assembly

When assembling a plastic frame with metal screws (e.g. ECO 8/16 and Logo 10) be sure to use a jeweler's screwdriver or a Wiha with a small handle to assemble the frame. If you use a large-handled screwdriver you will not be able to feel when the screw is fully inserted and you will probably strip the hole in the plastic frame.

8.1.5. Stripped threads

If you strip a plastic screw or setscrew hole, then you can fix it by squirting a small bit of CA into the screw hole and letting it dry to give the screw additional friction. But, it's better not to strip it in the first place.

8.1.6. Breaking-in motors

If you are using a brushed motor with carbon brushes, then you should "break-in" the motor before your first flight. This break-in procedure allow maximum contact of the brushes with the commutator. This will allow the motor to run at maximum efficiency and extend motor life.

Break-in is not required for these motor type:

  • Metal brushed motors. This includes motors such as the Team Orion Elite Micro Modified motor.

  • Micro heli tail motors. This includes both the gray and black endbell GWS IPS-style motors, and the N20 style motors.

  • Brushless motors. Brushless motors do not have brushes and therefore require no break-in.

There are at least two ways to do this:

  • Dry method: Run the motor for two hours at 1/4 throttle.

  • Wet method: Run the motor for 10-15 minutes in a glass of water.

Be sure to disassemble the motor afterwards and throughly dry everything, otherwise parts may rust. Don't use this method on motors which are assembled using bent metal tabs (such as the Piccolo motors) because the metal tab may break off when disassembling or reassembling the motor.

Be careful with the carbon dust. It can get into your lungs and cause severe breathing difficulty, especially if you're asthmatic.

Be sure to blow the carbon dust out OUTSIDE with some compressed air and don't get the carbon dust into your lungs.

8.1.7. Carbon dust

Beware of carbon fiber dust. It is classified as a hazardous material and can cause severe breathing difficulty, especially if you are asthmatic.



8.1.8. Capacitors

If you are using a brushed motor, be sure to solder three capacitors to the motor: one between the positive terminal and negative terminal, one between the postive terminal and case, and one between the negative terminal and case. This will reduce the amount of interference generated by the brushed motor.

8.1.9. Motor diode

If you are using a brushed motor, it may come with a diode which you may need to attach to the motor. The diode looks like a black barrel with a grey stripe on one side, and two leads coming out each end.

This diode prevents ESC damage by shunting the spikes of reverse current generated when the brushed motor rotates. So, you put the diode on the power terminals of the brushed motor. The end with the silver band goes on the postive terminal of the motor, and the end with no band goes on the negative terminal of the motor.

8.1.10. Ball links

Your ball links must move freely, but not be loose. If your ball links are too tight, you can put the ball link on the ball and gently squeeze around the edge of the ball link with a pair of slip-joint or ball-link pliers.

If your ball links are too loose, then they can be tightened by removing them from the ball then squeezing them gently across the face of the ball link with a pair of slip-join or ball-link pliers.

8.1.11. Motor shaft

For motors with 3.17mm shafts or larger: If your motor output shaft does not have a "flat" on the shaft, the pinion may spin around on the shaft because the setscrew can't grip the shaft. To put a flat on the shaft you need a Dremel with a diamond grinding tip, some masking tape, and a plastic bag.

  • Cut off about eight pieces of masking tape about 3 inches long. Take four of the pieces and make a # pattern across the front of the motor so the # will slightly overlap the shaft. Take the remaining four pieces and make another # across the front about 45 degrees offset from the previous tape, making sure it slightly overlaps the shaft again. This should completely cover the front bearing and will prevent metal bits from falling in.

  • Put the motor in the plastic bag, then punch a hole in the plastic with the motor shaft so the motor shaft sticks out the bottom. Tie the back end of the plastic bag. This will prevent metal shavings from falling into the motor and destroying it.

  • Grind a flat on the shaft using a Dremel with a diamond bit. Hold the Dremel so the metal bits are ejected AWAY from the front bearing of the motor.

  • Use some masking tape and wrap it around the shaft a few times to collect the loose metal bits sticking to the shaft.

  • Remove motor from plastic bag, being careful not to get any metal shavings into the motor.

  • Remove remaining masking tape from the motor.

8.1.12. Brushless motor wires

Brushless motor wires do not have polarity and can be connected in any order to the brushless speed control. If the wires are connected incorrectly, the motor will spin in reverse, and you can swap any two of the three motor wires later to reverse the direction.

It is highly recommended to use connectors between the ESC and motor so the motor wires can be disconnected from the ESC for safety during helicopter setup and maintenance.

If the wires between the ESC and brushless motor are too long, then shorten the wires from the ESC, not the motor wires. The brushless motor wires are usually enamel-coated copper wires from the stator windings and are difficult to solder if cut.

8.1.13. Canopy painting

Do not paint the canopy a dark color. You will need to focus on the canopy while learning to hover, so be sure to paint it a bright color or leave it white.

Also, some kind of decals are recommended to make it easier to see the orientation of the canopy at long distances.

8.1.14. Tail servo

Do not use rubber servo grommets when mounting the tail servo because this will cause tail wag when used with a heading hold gyro.

8.1.15. Mounting component

For micro helis: you can mount a gyro or tail servo on the tailboom by using either a cable clip or cable tie mounting plate. If you use a cable tie mounting plate, you may need to use two tiewraps to secure the mounting plate to the tail boom and/or use some hot glue to prevent the mounting plate from sliding on the tail boom.

8.1.16. Ball in swashplate

For FP micro helicopters: many micro helicopters do not include a swiveling ball in the swashplate to minimize slop. This makes the helicopter very difficult to hover.

There are upgrade kits which allow you to install a ball-in-swash on most micro helicopters. These are highly recommended. Like90 sells one, so does Pierre Hollister. See links section for URLs.

For even better control, you should put a small piece of fuel tubing above and below the swashplate ball to prevent the swashplate from moving up and down.

8.1.17. Removing CA glued joints

If you need to weaken the CA glue to remove a part, you can use acetone. Most regular fingernail polish removers contains acetone but the odorless types do not contain acetone and will not work. You will need to soak the glue in acetone for a while which will weaken the glue, then you should be able to remove the part.