WLToys F949

Introduction:

I first learned to fly using this plane, so it holds a special significance for me. The original brushed version weighs only 44grams without the battery and could pretty much float in place without any throttle once you got it high enough in the air. It also didn't hurt that the plane could fly for 20-30minutes on one charge. The major drawback to this plane is really that you can't fly it in anything greater than 5mph winds. Also, the motor burns out after around 10 hours of use. I didn't get anywhere near 10 hours (more like 5) since crashing it nose first into the ground tends to shorten its life. It has also spent many weeks of its life perched up on top of some tall trees through numerous storms.

After the motors were at the end of their useful lifespan, I decided to convert this to brushless. With the conversion, I could go one of two ways:

• Keep it at the same (or even lower) weight by using 1.7g servos & a small 6gram motor.
• Create a more powerful version and see how it fares in stronger winds.

Since I ended up buying another brushed plane to replace the first, I decided to go with the second option to create a more powerful version.

Components ($40):

• F949 air frame (not included in cost)
• 3x Hobbyking 15318B servos
• racerstar br-1306 3100kv (a bit oversized) mounted on a cap from a milk container
• Generic 10amp esc
• Redcon CM410X micro receiver
• Props: 5030

Conclusion:

Version 1: The plane came out to 66 grams (without battery) and 2 servos (rudder & elevator). I decided to go with a receiver with small jst plugs since that's what the servos used. However, since the esc came with your standard servo plugs, I had to cut it off and replace it with a small jst one.

After building the plane, I had to modify the battery tray (see video) by cutting it out and mounting it directly under the CG point. This way, I could use any size battery I want without it affecting the CG.

Please note that this conversion is not for everyone since the parts will run you more than the cost of the original plane. It really is a labor of love for those curious few.

After the first maiden, I realized a couple of things. First, the motor is pretty powerful for the small frame. The wings were flexing and will need to be stiffened up. The front landing gear also needs reinforcing due to the higher landing speeds. I am considering straightening out the wing to remove any dihedral and adding ailerons as well. It's going to be a really fun plane to fly.

Version 2 (update 4/26/17): I have added ailerons and two bamboo skewers under the wing to stiffen it up and remove any dihedral along with a 3rd servo for ailerons. It now weights 73 grams (without battery). With the added ailerons, it now feels more like your regular bank & yank 4 channel plane. However, I used larger batteries and it was a little over 100grams AUW which is twice as heavy as the original. The wing loading for the original was about 5oz/sqft and now it is 10oz/sqft. It actually feels fine at speed, but if you go slower, it can go into a stall quite easily (see the video Version 2 Maiden part 3). Stalls from the original plane were easily recoverable from even at a lower altitude, but not so much with the newer version. My controls felt completely dead after I encountered the stall. Landing is also going to have to be done at a high speed. Luckily, the nose first landings haven't destroyed the motor windings like it did on my FlyBear conversion.

Overall, there is no longer any resemblance to the original plane other than the exterior. The flight characteristics are completely different and the flight envelope is much smaller. It needs to fly with some speed due to the higher wing loading. With a 5030 propeller, it flies at a brisk pace with half throttle and you need to bump it up to 3/4 throttle during turns to prevent stalls. There is plenty of room to move up in prop sizes with this motor. I may bump up the prop to a 5045 to see how it performs in the future. If the original plane is starting to feel a little boring, then a brushless conversion may liven things up a bit for you. ;)