Here are the build details and some videos of my first hot wire flying wing made with my CNC foam cutter. If you’d like to build a foam cutter then I have all the information here http://www.rckeith.co.uk/cnc-hot-wire-foam-cutter/.
I’ve called it the YMF-38 as its 38-inch wingspan. It uses MH-42 airfoil sections and a 2200KV brushless motor with a 6×4 prop. A 2200mAH Lipo gives about 8-10 minutes flying. It flies really well and is quite fast. I used XPS foam with 9-gram servos. I’ve had a few servo failures using the cheap 9 grams so now I use the metal geared MG90S which are sometimes as cheap as the plastic geared servo’s.
I’ve built a few now and use white Styrofoam as well, a bit cheaper and if you follow my covering process http://www.rckeith.co.uk/cover-wings-fuselages-brown-paper-white-glue/, very strong.
If you need Free options to make the wing then LinuxCNC and my article http://www.rckeith.co.uk/foam-wing-free-cnc-software/ here has all the details.
The carriage distance is 32″ and the root of the wing is set at 6″ from the carriage. The two downloads below are the actual g-code you send to the hot wire CNC machine.
Here are the dimensions. Center of Gravity is 6 1/4″ from the nose. The end plates are 6mm depron which you can be any design you like.
Here’s the setting from Profili2 Pro
Once you’ve cut the wing then you need to trim the root and tip to the correct angles. Check my video https://youtu.be/_UFOHJPlza8 it explains the process and will save wasting a lot of foam.
Here’s the placement of the 3mm carbon rods. I use a Dremel with tile attachment to cut a slot and filled them with lightweight filler.
I then covered it in iron on Solar film. The battery is secured with velcro and a velcro strap that goes through the wing. The launch is very easy because on the underside there is a small grip which you can hold and apply about 3/4 throttle and she leaps away. See the second video below the video’s below
Here’s the finished YMF-38. She flies extremely well and can really eat up the sky
I crashed it. I’d forgotten to check my transmitter rates switches and the elevator was on a low rate setting. Took off and thought this wasn’t right better land, but before I could it just wouldn’t pull up and I end up in a field of oilseed rape (canola) crop surrounding the flying field. Tried to find it but this type of crop it very difficult to get through when it’s almost ready for harvest, so I had to leave it. Damn.
Well after about 2 weeks the crop was cut and one of the other club members spotted it on his way home. Everything still worked apart from one servo but I will not trust the receiver as the whole air-frame felt wet. So time to make another.
New Hot Wire CNC Wing
This is the rebuilt wing I’ve used white foam and 3 carbon rods and then its been covered in brown paper and solar film. Weight was 405 grams without battery and with a 3S 2200 mAh 608 grams. The videos below show the search, recovery rebuild and Maiden flight.
- Part 1 Crash, Search and Recovery, Foam cores made on Hot Wire CNC
- Part 2 Spars, Joining and covering in Brown Paper, PVA
- Part 3 Covering in Solar Film, Final assembly and Maiden Flight
- Part 4 Onboard footage and some 4S Lipo Fun