(0) Cart
  • No products in the cart.


BlogHome » Helicopter

Repair non-connecting v911 5-in-1 RX

Every now and then, I see a flurry of post about v911 RX that refuses to reconnect or rebind to the transmitter. Often times, this occurs following a crash. The symptom is upon plugging in the battery, the RX LED immediately turns solid without blinking, or sometimes, it does a series of rapid blink and then turns solid much quicker than normal.

A number of us learn that the cylindrical crystal that is responsible for the timing of the circuit has gone bad. Replacing it usually fixes the issue. I’ve had this happen on three RX already, and solding on a new one have fixed the issue all three times. So it’s worth a shot instead of throwing the RX away.

For the repair, you need a working 16mhz crystal. You can purchase some on eBay or DigiKey. Or grab one from a non repairable, broken RX board.

The ones I got from Ebay is actually smaller than the original. Whether it’s more dedicate and prone to getting damage as a result, I can’t say yet. Time will tell.

Here’s the two side by side. The original on the left and the Ebay version on the right.

Comparision of the stock v911 16MHz crystal versus the replacement one.

It was easy for me to solder on the new crystal from EBay. And it works like a charm. Here it is soldered to the same location on the v911 RX. It doesn’t dangle past the RX edge like the original one. Just need to glue it down to secure it in place.

Replacement 16MHz cylindrical crystal soldered in the proper location on the v911 RX.

I purchased 50 of them, so let me know if you need one in a pinch.

Categories: Helicopter, Repair, v911
17 Comments on Repair non-connecting v911 5-in-1 RX

Carrying Case for Micro Helicopters

I took this photo to share on RCGroups. I figured I’ll post here as well.

RCGroups forum member Heli Pad gifted me this Harbor Freight Tools case and I configured it to hold 5 micro heli.

From top to bottom:

  1. Blade mCP X with extended tail boom
  2. WL Toys v911 (HobbyKing FP100)
  3. Blade mSR
  4. modded 9958MSR
  5. Xieda 9958 (HobbyKing HK-190)

Perfectly fits five micro helicopter and full size transmitter.

All those brands and model of helicopter are flown with the Turnigy 9x modded for DSM2 capabilities.

Behind the foam on top are pockets for the tools and extra parts. You can see how those pockets looks like over at Harbor Freight’s site.

I pulled out a block of foam, keeping them intact. Then cut a 1/4 off the bottom and reinserted back into place. It makes a nice little recessed compartment for my 1s LiPo battery.

1S LiPo compartment recessed.

Can anyone guess what this little momentary switch is for?

Little pressure switch hot glued into place.

If you guess that the switch is connected to the LED light strip at the top, you’d be correct. It gets toggled when the case is close, turning off the LED. We usually fly at the local park after my kids are put down for bed, so the light strip is great. I rigged up a 3S LiPo to power the LED light strip. The strip of LED was like $5 bucks at Hobby King, and has adhesive on one side. You cut it to the length you need. Then I used a 3S 2200mAh LiPo to power the LED because that’s what I had handy. You can probably go with something less. However, I intend on putting in a charger that will pull power from the same LiPo in the future. So that 2200mAh LiPo should work out pretty well.

Strip of white LED lights hooked up to a 3S 2000mAh LiPo.

Here’s the configuration…

And a charger powered off the same 3S LiPo pack that powers the LED

12 Comments on Carrying Case for Micro Helicopters

Evolution of the mSR X Brushless Mount

Just wanted to share the evolution of my mSR X brushless mount.

I find it’s easier to design on the computer. A digital caliper is a great tool to transfer the measurements into your graphics program. A CAD program is ideal. I am more familiar with Illustrator, so that is what I used. If you can scan your object, you can use that scan as an overlay to trace it’s physical dimensions. Doing it this way allow you to make precise changes on the computer. The low tolerance and need for higher precision is very important at the size of these micro helicopters.

Here’s a previous design for the AP-03 motor. Unfortunately, this motor wasn’t enough power for the mSR X.

Prototype of the mSRX AP03 brushless motor mount. The AP03 doesn't have enough power for the mSRX.

Then print and cut out some on paper. Or you can print onto label paper that you can peel and stick to a plastic credit card. This allow you to cut out the prototype with a xacto knife and scissors. You’ll find you need to do a few to narrow down the design.

Various mSR X AP03 prototypes on paper and plastic

Once you’re happy, you use the same method of printing onto a label paper and sticking it on top of the material you want to make the mount out of. I used 0.8mm weaved carbon fiber sheet. I used a dremel and freehand the cut out and a file to clean up the shape. It wasn’t too difficult work, and didn’t take too long at all. However, if you have access to a CNC router, the prototyping stage goes by so much faster and easier.

Here’s a couple of photo of the final result. I consider it a prototype, but it could qualify for production work. It’s very polish and wowed the owner of the mSRX and friends who have gotten to see it in person.


I felt that the stock mSR X was very underpowered the first time I got to fly it. Because it was underpowered, I couldn’t bail out of bad situations. The positive quality of the mSR X is quickly the flybarless heli respond to your cyclic command. It was near instant. It’s a pity that it lacks power. On top of that, there seem to be a huge problem where the stock brushed motor tend to die very early deaths. There’s a whole thread from owners tracking the issue.

After the mod to a brushless motor, the mSR X finally has the pop I like to see in my micro heli. I personally think it should have came this way from the factory. It is definitely worth it for those with mSR X. The brushless ESC, motor, mount and wires all weigh less than the stock brushed motor. Isn’t that amazing?

Stay tune for the rest of the how to’s on this series. Until then, take a look at preparing for flashing the ESC here: Silicon Labs USB Toolstick Mod for BLHeli Flashing

Categories: Brushless, Helicopter, mSR X
4 Comments on Evolution of the mSR X Brushless Mount

Xieda 9958 er9x Settings

Just a quick post. Some people who have flashed their Turnigy 9x to use the er9x firmware can load my Xieda 9958 model into their radio using the eepe (EEPROM Editor for er9x FW). You can get a copy of eepe for Windows, Mac and Linux here: http://code.google.com/p/eepe/

Then use the eepe program open up my Xieda 9958 model and save it to yours.

Link: Daryoon’s Xieda 9958 settings for er9x

Some info about the settings…

Two primary flight modes:

  • The FN switched to ID0 will put your heli in a more aggressive mode. Negative expo to make your cyclic controls more sensitive in the middle. The throttle curve is a little more aggressive. Uses curve 1.
  • The FN switched to ID1 has zero expo and a more “gentle” throttle. Uses curve 2. If you want a linear throttle curve. Set your throttle stick to use curve 3.

Flip the rudder D/R switch to add more negative expo to the rudder. If find it’s good to have the head of the heli whip around quicker using the negative expo.

POT3, which is labeled as “PIT TRIM AUX.2” is a mix that adjust endpoint. Fly with that POT at 100% for full throw. Rotate it slower if you need to go into “junior/beginner” mode. Same function as the factory transmitter junior/senior mode, but with more choices in between. :D

The flight timer is set to 5mins and will beep at the last one minute and each of the last 10seconds of flight. It is link to the throttle stick so the timer only counts down when the thottle stick is move away from zero.

Lastly, the throttle cut function works. Just activate the throttle cut switch and your main motor shouldn’t spin. Good safety.

Let me know if you guys have any difficulty and I can write up a more thorough guide. Also, remember you need to calibrate not only your sticks, but your POTS as well. It’s all done in the same location. I do it each time I flash the firmware.

Categories: Helicopter, Xieda 9958
1 Comment on Xieda 9958 er9x Settings

Hobby King’s XP 3A Brushless ESC

For those looking to upgrade the MOSFET on the XP 3A, here are the location of the N-Fets and P-Fets.

Location of the N channel and P channel MOSFET on the XP_3A

You can replace the N-FET with the DMN2041. This takes the resistance of the original FETs from approximately 30 mOhms down to 26 mOhms or even 13 mOhm stacked as mentioned below.

The P-FET can be replaced with the DMP2035. The P-FETs original resistance is approximately 60 mOhm. Replaced with the better quality FETs, you take it down to ~30 mOhm or 15 mOhm stacked. Quite a difference. Less resistance means less heat and more power going to the motors.

As alluded to above,  stacking two or three of them together effectively lowers the resistance and basically “upgrade” the ESC so it can handle more current through them. Here’s a great tutorial from AtomicMods that demonstrate how to stack FETs.

Tutorial 1:28 XMODS Generation 1 Stacked FET Installation

See this awesome thread and work by Steffen, author of BLHeli brushless ESC firmware code where I gleamed much of this information. Look for more post on the subject as I attempt to convert a mSR X and Xieda 9958 to utilize a brushless motor.

Categories: Brushless, Helicopter
2 Comments on Hobby King’s XP 3A Brushless ESC

Brushed Main Motor Micro Heli

Looking at the three motors I happen to have apart, I noticed the winding is so different between them. The Xieda 9958 version 2 motor, the v911 and the mSR are all slightly different. I don’t know how this relates to the power these brushed motor is able to produce. Anybody know?

I saw that the mSR, v911 and 9958 had similar can diameter…that was off by 100th of mm. They are 8.42mm to 8.46mm to 8.55mm respectively. All seems to fit each other’s frame…though it can be a little lose if you don’t put some glue or tape as needed.

The 9958 and mSR both have very tightly wound wires. It was densely packed and thickly wound. The wires themselves may be ever so slightly smaller gauge than that used by the v911. The v911 had lots of gaps where you can see through. Not sure if this is a good thing or not.

You can see the v911 versus the mSR’s in the follow photo:

Here’s the various component of the brushed, coreless main motor.

The various components of the brushed motor. This is the Xieda 9958 version 2. I call it version 2 because the first version was black/white wires and the can had holes in them.

Here’s a photo of the brushes themselves.


Categories: Helicopter
10 Comments on Brushed Main Motor Micro Heli

Charging Clip for Nine Eagles, Trex 100 and v911

If you fly micro helis such as the Solo Pro, Trex 100 and v911. You’ll quickly find that they each employ their own proprietary battery connector. What is an easy way to be able to hook these battery up to your programmable charger?

Simple. Take a clothespin and insert two tiny screws 5mm from each other. Then wire it up like the photo below to create a charging clip.

You can make more than one and wire them up to parallel charge. It’s easy to clip on and off and works great.

Pertinent Links:
RC Groups forum post

5 Comments on Charging Clip for Nine Eagles, Trex 100 and v911

E-Flite 150mAh 25c 1s LiPo Test

I finally got a hold of the new EFlite 150mAh 25c LiPo. I was curious about this cell because a Horizon Hobby employee said that the chemistry is better than their prior 1s cells. One person on the forum noticed that the head speed of their mSR X has a higher pitch, which suggest it was turning at a higher RPM than their Hyperion 160. That with the MSRP of $5.99 and Horizon Hobby listing it for a reasonable $3.99, it made me want to get one to put to the test. This proved to be difficult to find as it’s out of stock everywhere. The times when it came in stock at my local hobby shop, they marked it up at $9.99. This is the Hobbytown in Escondido. They also marked up the Hyperion 160mAh to $9.99 that can usually be found for $6.95 elsewhere.

New E-flite 150mAh LiPo

Anyways, finally found one at Discount Hobby Warehouse for $5.99. My curiousity got the best of me and I grab a single cell for testing. Now, bare in mind that the performance can vary from cell to cell. And I like to have at least three cells to give a better representation of it’s performance. But it’s interesting to see the result nonetheless.

It was nicely packaged. Weighs in at 4.4g. You can reduce that slightly if you remove the sticker because it wraps around the entire cell, with a little tab on one end. Anyways, make sure to click on the graph below to view it full size.

I need to grab a new order of Turnigy 160 and Turnigy Nano-Tech 160 from HobbyKing to see if those cells are really that bad or the ones I have are just worn. I also have some MiniAviation 180mAh coming from the UK. Will put that to the test once they arrive.

Categories: Helicopter, Test
6 Comments on E-Flite 150mAh 25c 1s LiPo Test

v911 Main Gear Alternatives

I was given a Xtreme Productions delrin main gear for the Solo Pro. So I took the weight differences between the v911, Solo Pro and Xtreme.

The v911 is the lightest, and very slightly thinner than the other two.

Here’s the weight of the stock v911 main shaft compared to the Solo Pro’s carbon fiber main shaft. In case you’re wondering, the Solo Pro main shaft is a drop in fit. No mods needed.

Categories: Helicopter, Solo Pro
Leave a comment →

v911 Battery Tray Adapter

WL Toy’s v911 is a fun micro RC helicopter. But because of it’s unique battery connection, you are limited to the factory 120mAh LiPo or recently released 130mAh LiPo. Here’s a mod that takes the battery connector part and turn it into a battery tray so that you can use the popular 1s LiPo with the Parkzone/E-Flite ultra micro connectors.

First, use a wire cutter or nail clippers to cut along the yellow line. Use a file to get everything smoothed out. It should look like the piece on the right when you are done.

Use a pair of wire cutters to cut where indicated. It should look like the piece on the right when done.

Then you can slip into the existing battery slot on the v911 skids. You will also need to solder on some ultra micro plugs.

The new adapter fits right in to form a battery tray. Solder on some ultra micro leads.

For those concern with the stock center of gravity. The fit is tight enough that you can position the battery where you like.

Here, you can see the battery position at about the stock location. Personally, I prefer the Solo Pro location. Fully forward, and into the canopy. :)

Battery seated at about the location of the stock LiPo.

You can make the battery tray more secure if you glue it to the skid. I have tested and found that ThunderPower 160, Hyperion 160, E-Flite 120 fits perfectly. I can also fit Turnigy 160 battery as well. Though I have had one where it was too thick to fit. The NanoTech 160 are definitely too thick for this mod. I recommend getting a Solo Pro skids if the battery you run are the NanoTech 160.

Categories: Helicopter
2 Comments on v911 Battery Tray Adapter
Page 2 of 512345