The KFm4 NanoWing flew so well I wanted to see how far I could go with the FPV race wing design. This then is the obvious evolution…

NanoWing 600mm FPV Race Wing

It all happened rather quickly really. I loved the way the original KFm4 NanoWing performed but knew there would be those out there who can never truly trust an aircraft that doesn’t have a “proper” airfoil. I also wanted to explore whether the performance of the KFm4 version could be replicated with a true symmetrical airfoil or whether there was something going on that allowed the stepped KFm section to carry all that FPV gear in such a tiny wingspan.

Symmetrical Vs Flat airfoil

FPV Race WingYou might notice that even though this isn’t a KFm4 section it IS still a symmetrical wing. Why build a flying wing with a symmetrical section when just about every other wing out there has a flat bottom section such as the ClarkY or a semi-symmetrical such as the Tsagi or RG15? The answer all comes down to penetration – or at least my dire attempts to beat the continual coastal breeze/howling gale we have here in this part of Australia.

Whereas flat bottom sections produce more lift, they are prone to buffeting in windy conditions. This as we all know is difficult to stabilize in a flying wing and we end with the yaw wobbles. Semi-symmetrical sections are better but can be hard to produce accurately using a folded foam construction. Fully symmetrical sections however are designed for speed and manoueverability – two things I wanted in abundance for an FPV race wing!

Construction was easy – simply mirror the Flite Test Versa Wing style cut and fold technique on both top and bottom surfaces. The only bit where you have to be (more) careful is when gluing it all together. As long as you ensure the spars line up and the trailing edge of the bottom surface lines up with the elevon hinge line then you should get a nice symmetrical section.

TIP! Put hot glue into the cut/crease/fold lines in the front of the wing to strengthen the leading edge. Glue the wing in two stages: First glue at the spar top and bottom and then bring the trailing edges together.

Incidentally, to keep the build neat the tape finish was applied before assembly and all the RC/FPV gear installed into the wing before final assembly as well.

Other changes…

FPV Race WingI made two other minor changes to the original design in this build as well:

  1. I changed the motor mount. The original simply clamped onto the foam wing but this posed two problems now – firstly it would be hard to clamp a curving surface well and secondly I really didn’t like the way the motor bolts were impossible to access and the way the ESC was mounted. The new mount is much more refined and fits into a slot cut in the back of the wing. You retain full access to swap out motors and there is even a tray to mount the ESC with plenty of airflow around it.
  2. I extended the winglets a little more backwards. This was purely an experiment to find the sweet spot between form and function.

Flying πŸ™‚

Well, you’ve seen the video already so you know why the smiley face. The Nanowing V2 flies just as well as the original FPV race wing and maybe even a little bit faster. Yes, you do have to watch that stall a little more carefully but are rewarded with a long, smooth glide. It is a sturdy design and looks great in the air. The pod does the trick to mount and protect the LiPo and FPV camera and I found as with the original it balanced perfectly without any added weight.

Speaking of weight. I expected this version to be lighter than the original but I was wrong! This wing is actually 20g heavier with an identical electronic and FPV setup. It doesn’t matter in the slightest when it comes to performance but it puts to shame all those comments about KFm wings being heavy!

So can I build one of these then…?

Be my guest! I’ve drawn up the plans for you to download and build. This will use a single A0 sheet of 5mm foam board. For those who need to know, the plan dimensions are in brackets after the download link.

The motor mounts, pods and control horns will be available for purchase through Red20RC in the near future but if you do build one please let me know as I would like to review this later in the year and maybe create a wall of NanoWing build images.

Until next time then…

 

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