ptern's blog View Details
Posted by ptern | Apr 03, 2021 @ 06:45 AM | 3,570 Views
This is a mini of how to make such a tail mount.

It is up to you to decided which material works best for you. All dimensions are in mm.

The material I am using is a fibre glasss blank PCB of 1.5mm in thickness.

Have fun guys

EDIT: forgot to mention that you'll need to drill two of the 1.7mm holes on both sides of the boom that hold the motor mount.
Using the 2mm screw to 'tap' the holes.
Posted by ptern | Mar 12, 2021 @ 10:22 PM | 9,495 Views
Hi all,

This thread is for beginners and intermediate level of pilots (like myself) to explore and experimenting with the Torque Assisted Left Yaw idea.
Ideally, this feature should be implemented in the Flight controller (FC) due to the complexity of the control/feedback mechanism.
However, I did experimenting this feature with just by program my Jumper T16 radio and was very delighted with this feature.
Big thanks to whoever came up with this idea and implemented in the FC.

WARNING: The most important is to back up your model/radio settings before adding this feature.

For the radio setup, it is very simple. We will need a 5 point curve and mixes in the radio mixer. Attached are the two pics showing the settings via the OpenTX Companion.
After settings are done and saved to the radio, you can check on the radio display for proper function of the new feature.
The next step is to remove the main blades and do a real check on the heli itself. Ensure the heli is also secured during test due to the tail rotor's action.
Referring to my setting, when the radio in normal/throttle hold and Idle2, at 0%, the main motor should not be running when the yaw stick is moving in both left/right direction. In Idle1, place the throttle stick at mid stick and yaw it to the left. You should see the motor speeding up/ down accordingly. Now try to pull the yaw stick fully to the right, the motor should be constant at the Idle1 speed.

Feel free to adjust the values in the Idle1 to your liking as per described in the pic.

The instruction provided here is for experimenting purpose, if you are not confident enough then don't do it.
All setting values are based on my JumperT16 running on my M2 with an external SFHSS to SBUS radio module.
For your radio and receiver, the values may be different, for example, channel reversal, 0:100% (spektrum) vs -100% : +100% (for OpenTX) etc..

Shoot me a message if this feature does help you to fly a bit better.

Posted by ptern | Sep 29, 2020 @ 09:12 PM | 8,728 Views
This blog is for people who wishes to send me photos or screenshot or whatever...
To make it clean, after I review the info, I may remove them so don't expect the info stays here forever.
Posted by ptern | Sep 05, 2020 @ 01:45 AM | 10,971 Views
For congcon,

Here are photos for your info.

Note that I was experiment with the trex150grs gyro but this is the same for the K110 gyro as well.
You'll have to mount the rear servo to make the correct moving direction as the K110 has a front servo.

So in summary, the BEC 5V is bypassed the gyro and being fed directly to the 3 cyclic servos and also to the gyro via the small servo cables.
Posted by ptern | Aug 16, 2020 @ 09:43 PM | 11,924 Views
Hi all,

A few people were asking me for the easiest way to program BLHeli esc'es.

Here is a short instruction of how to.

You'll need:

1. usb to serial converter
this is an example from ebay :

2. a 1k resistor

3. a schottky diode : for example sm5819a

4. a PC running BLHeli suite and the driver for the usb to serial installed. I am assuming we are using WIndows OS.

5. A BLHeli ESC flashed with blheli bootloader.

See the photo for connection.

More to come
Posted by ptern | Jul 13, 2020 @ 11:04 PM | 10,632 Views
Here are a few pics of my new helicopter. Work in progress. I named it the PT-DMD130

What it has:

brushless DMD main motor (RaceStar BR2212 1000kv 2/4s)
Tarot tail hub as main rotor hub
x3 linear cyclic servos
brushless tail motor
running on 2s batteries.
Posted by ptern | Feb 27, 2020 @ 08:05 PM | 10,937 Views
Hi all,

For the benefits of those wanting to use the K110 gyro as the flight controller, I am posting wiring diagrams showing how it is done.
The first diagram is for brushless tail, note that the 5V BEC is only driving the three cyclic servos and the K110 gyro, any BEC capable of 1.5A would be enough.

and the second diagram is for 1s brushed tail, note that the 5V BEC is driving the three cyclic servos, the K110 gyro and the tail motor so the 5V BEC must be capable of at least 3A or better.

HINT: Beware about the quoted tiny '3A BECs' sold on Ebay, Aliexpress and Banggood. Although they advertiseds as 3A, however, for most of them, the 3A figure is the burst current for about 10 seconds. I bought a batch of 10 of them on Ebay but have to return them. Testing them revealed the continuous current is only 1.5A and even so, they got very hot to the touch. And yup, those are rated as 3A capable, which is a load of trash.
Posted by ptern | Feb 25, 2020 @ 11:59 PM | 12,774 Views
Hi all,

I was working with BLHeli firmware for a while just to adapt the control signal to accept PWM up to 16kHz.
The reason for it was, the WL-Toys K110 gyro board is an excellent flight controller and has the tail signal of 16KHz PWM.

With my shallow knowledge of BLHeli, I'll try to explain the differences between BLheli Electronics Speed Controllers (ESC).
The purpose is to help those newbies to select the correct type of BLHeli ESC for their vehicles.

Currently, there are 3 types of BLheli ESC's: BLHeli, BLHeli_S and BLHeli_32

BLHeli: The birth of an open source firmware for ECS's. The target was for tiny micro helicopters and was
started with the 8 bit ATMEL microprocessor, the mega8.
It was proved to be popular so it expanded into multi-rotors vehicles.

But soon, the mega8 was found to be lacking of resources and power to control various type of motors.
It was then replaced by the Silabs processor. Silabs BLHeli based on these three type of processors:
C8051F310, C8051F330 and C8051F390, the higher the number, the more advance and faster processor.

BLHeli supports MAIN, MULTI and TAIL motors. BLHeli came with two varieties: Atmel and Silabs processors

BLHeli_S: As soon as the BLHeli exploded with multi-rotors vehicles, more advance functions are required so the BLHeli designer switched to the more advanced and even faster Silabs processors, the 'BusyBee' family and they came in these varieties: EFM8BB1, EFM8BB2 and EFM8LB1.
To distinguish from the earlier...Continue Reading
Posted by ptern | Dec 21, 2019 @ 03:12 AM | 12,100 Views
There is no amount of dampening will get rid of the vib to the gyro.
You will need to eliminate all of the vibs in the first place, and it is good for the heli anyway.
High level of vibrations will cause high wear and tear on the bearings or moving parts.

On both of my DMD K130s ( and 2s K110s), the gyros do not have any foam at all, just a bit of packing tape to
stick and secure the k110 gyro to the frame and that is.

I am sharing my experience of eliminating vibs at the hardware level:

1. Main head component checking:
- Physical check the main head for vibs:
carefully inspect for 100% straight main shaft(if in doubt try a brand new main shaft)
next check the feathering shaft. Remove both main blades, use a fs screwdriver , rotate the fs while watching the the main grips.
They should be level and should not wobbling up/down while the fs is rotating. If they do wobble, the fs is bent and must be replaced
Check the 2 head damping rubber O rings, one for each grip, check if they are not worn out or broken.
These two O rings can cause head vibs if they are bad.

For the main blades, if in doubt, you'll need to check if they were balanced.

Check the main motor for any vibrations, Worn out bearing will cause vibs.
Check the main plastic gear for broken teeth etc....

- Checking vibs during power with main blades attached:
unplug the tail motor, set pitch to 0 deg from 0 to 100% throttle.
secure the heli to a platform or you can hold the heli in your hand during this test but...Continue Reading
Posted by ptern | Aug 28, 2019 @ 12:02 AM | 9,761 Views
I'll make an instruction of how to make customised push rods for your micro helis. There are many reasons why you would need such a customised push rods.
For me it was the customised head for my K130 helis which I use the Tarot450 tail assembly.
The reason I chose the Tarot tail assembly, the grips have builtin thrust bearings, hence totally eliminate the centrefugal loading on the grip's radial bearings.
Let me know if you are interest in this head from the Tarot 450 tail, I'll make some instructions.
Now... the instruction for making push rods.
Posted by ptern | Dec 10, 2018 @ 09:25 PM | 23,398 Views
I am starting this thread on how to rewind the K110 1s motor to make it run on 2S.
The preferred new wire size is 31AWG gauge or 0.226mm or 0.0089 inches wire diameter.
Posted by ptern | Jun 10, 2018 @ 05:20 AM | 22,527 Views
Here are the mentioned files. Since I have none of this ESC, I could not test them. Please test them at your own risks.