DW Mini Rainbow

Introduction:

This was my first flying wing and technically my third plane. My first was the WLToys F949 and my second didn't really count since I lost it in a tree during its second flight. I was always intrigued by flying wings and was excited by the prospect of building my first plane and learning how to fly a wing. I bought the kit and wanted to see if EPP foam was going to live up to all the hype which surrounded it.

Components ($45):

• DW Mini Rainbow kit
• 2x 9gram servos
• Generic 10amp ESC
• 4 channel micro receiver
• Racerstar BR1306 motor 3100kv
• Carbon fiber spars (1mm)
• 6030 propeller
• 2x control horns & push rods (16awg wire)

Conclusion:

I learned a lot from this wing. Build wise, it taught me how to build light and strong along with challenges of maintaining the proper CG with tail heavy wings. My first version was heavy and didn't fly. I had to go through many iterations in order to finally get it to fly. The major challenge in this was not knowing if the issues stemmed from my lack of experience in flying or something with the build itself. I ended up crashing the wing hundreds of times (hard). I was amazed at how it took all the crashes in stride. The weak wire at the solder joints failed numerous times from the hard crashes before the EPP wing finally started to crack. I reinforced the weak areas with carbon fiber (mainly near the rear) and strapped down sections of wire so the impact would not stress the solder joints. To address the weigh issues, I had to remove nose reinforcements I built in initially and cut out parts of the balsa wood. If you look closely at the nose, you'll see that I had to tie the batteries down with twist ties. They are really light and strong and has worked really well for me. The batteries haven't come loose yet during hard crashes.

Learning how to fly this was a humbling experience to say the least. While I could fly the 3 channel F949 really well by the time I took on this project, I didn't realize how different wings would be. My recommendation for those that want to learn wings would be to start with a ready to fly one or at least build a popular one with lots of online support (like the Flite test Mini Arrow - I have another page with this build). Don't buy a kit with vague instructions and then source your own parts until you've had the experience. The mini arrow flies perfectly the first time if you follow the instructions exactly and balance the CG properly.

If I had to do it again (and I will since I have another unbuilt kit of this), I will use 5g servos and a larger motor. I still vividly remember when I first flew this, it felt like a rocket compared to my trainer and I had no idea how people could want more speed than this. Now that I've learned how to fly wings, the 1306 motor seems a bit underpowered. It has enough power to do all you basic aerobatic maneuvers and can fly fairly slow as well, but will lack excitement for those with more experience. I'm eyeing some 20g motors and I will also probably do away with the balsa frame completely. I think it's just dead weight since you need to put all the electronics near the front of the wing anyway to get the proper CG.

This is a great wing for those who want something compact and can handle lots of abuse. EPP is great and I look forward to using more of it in the future. Reinforcing it with spars is a more than adequate tradeoff for its impact resistance. Just make sure you know a thing or two about building wings though before you start.