I set out to create a fast race wing that blended the success of the original KFm4 MicroWing with the size of the Turnigy Bonsai. I think I might have succeeded!

NanoWing – 600mm KFm4 FPV Race Wing

KFm4 MicroWingI already had a pretty good idea of what I wanted to end up with as I was sat looking at a pile of KFm4 MicroWings I had cut for a school project. The list of requirements was simple:

  1. Must be 600mm wingspan to compete in the same class as the Bonsai/Mini PopWing
  2. Must be foam board or Depron construction to keep cost down
  3. Must be quick to build and get flying
  4. Must use mini quad type motors/ESCs/props/LiPos
  5. Carrying a HD camera nice but not essential
  6. MUST FLY FAST AND STABLE!

Designing the NanoWing

NanoWing – 600mm KFm4 FPV Race WingThe first step was simple. I just took the original MicroWing and chopped 100mm off of each wing to give a 600mm span. The result looked a little weedy and previous experiments had told me I needed a bit of wing area to lift what would be a fairly heavy frame. I stretched out the chord a little and the outline was soon looking like it meant business.

Following in the footsteps of the MicroWing I was certain this should also be a KFm4 section. The symmetrical airfoil gives a stable flight performance with excellent penetration in high wind.

Because this was going to be a FPV wing I wanted to employ something similar to my successful FPV pod in the design. I thought about simply modifying the existing design but decided that would lead to weight and balance problems so instead I designed a whole new micro pod capable of securing the FPV camera and flight battery in the nose.

The winglet design I took from the new Katana X KFm6 wing with simple squared winglets extending rearwards to improve tracking. By the time I was finished I was really happy with the 3D render in front of me.

Building the NanoWing

The build was simple as all Kfm wings are being mostly straight lines and flat plates. These days I tend to cut the panels and then cover them on the outer skin with packing tape before assembly. This makes finishing easier and neater than if I tried to work around servos and right angles.

I’ve found that if I use the right spray adhesive I can get a good instant bond on coated foam board. Just look for the acid free type used for permanently fixing artwork, photos or fabrics. A quick spray on the smaller panel to be mounted, press it into place and away you go.

To get a nice profile on the leading edge I used a technique suggested to me during the MicroWing UAV build. The foam board panels are stepped at the front and then filleted with thin strips of Depron foam. Depron is much easier to sand than foam board and you can get a nice smooth leading edge in no time. Strips of reinforced tape were then wrapped around the front of the wing to produce a nice tough leading edge.

And that’s about it. Channels were cut in the foam for the wiring and then coated with tape to give a clean finish and the G10 pod and motor mount glued into their slots with hot glue.

Job done!

NanoWing – 600mm KFm4 FPV Race WingΒ  600mm KFm4 FPV Race Wing

Off to the field then…

It’s video time!

So it flew and it flew well. There were a couple of issues that I discovered though and these got fixed before the next flight…

  1. The pod didn’t protect the FPV camera well enough. That inward curve might look nice but it leaves the camera vulnerable. A new pod with an outward radius at the front provides a strong bumper to protect the camera.
  2. The 5″ triblade props seemed like a good idea but a 6045 Gemfan gave me nearly 100g more thrust.
  3. The motor mount whilst solid did not make changing out a burnt motor easy and the ESC was just plonked on top of the wing. A new mount was designed that slots into the wing allowing easy access to the screws and providing a solid and protected mount point for the ESC.

With these changes made the NanoWing is a fantastic little wing. Fast enough on 3S to keep you on your toes but stable enough to not be scary. There isn’t any stall to speak of and no death spiral if you slow things up a bit. Of course, the glide is steep being a KFm wing but still controllable with throttle for landing.

I did try a flight with a 4S pack and the results were impressive. With those extra volts the NanoWing becomes a truly ballistic missile! Sadly my ESC wasn’t up to the task though. A little magic smoke later and I lost the motor, ESC and receiver in one go!

So can you build one?

Please do! I have drawn up the plans and the pod and motor mount will be available through the Red20RC store soon. If you don’t want to use the pod just use your imagination to fill in the gaps and strap everything down in a more traditional method.

Specs:

  • Wingspan – 600mm
  • Construction – Foam board (5 or 6mm), G10 fiberglass
  • Target AUW – 380g
  • Motor – 2204/2300
  • ESC – 12-20A BEC
  • Prop – 5045/6045
  • LiPo – 1000-1300mah 3S/4S

Plans:

Build, fly, race, crash, repeat…

 

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