As someone who’s tinkered with electric motors in various hobbies for many years, I was pretty underwhelmed by the latest electric leaf blowers on offer. It can’t be that hard to design a leaf blower that actually achieves its namesake, right? So, I set about researching Electric Ducted Fans (EDF) and how I might squeeze one into a leaf blower form. I erred away from the cheaper plastic units and went for a 90 mm Wemotec Midifan Evo bolted to a HET 700-68-1400 kV brushless motor. Extreme RC talked me through all my options and offered me a balanced unit that had already had some bench time and produced about 4.5 kg thrust. I chose to power it with two five cell LiPo batteries in parrallel (10 cell) and a 110 A Hobbywing Flyfun Electronic Speed Control (ESC). A simple servo tester was used to control the unit. With the powerplant all sorted, it was time to turn my attention to the chassis.

As someone who has always loved radio controlled cars, it was a no brainer for me to adopt a composite style chassis that would allow me versatility in mounting the various chassis components. I don’t have a CNC router to cut carbon fibre plate, so I relied on 3D printing to do the hard work. I drew up the design in Autodesk Fusion CAD software with carbon fibre filaments in mind. Bambu Lab’s PPA-CF filament seemed perfect as my design utilised the jet housing a stressed member of the chassis meaning that strength was important. Other less critical components were printed using ABS and PLA filaments. The chassis was 3D printed with 3 mm hardware joining the 28 odd parts together. One 4 mm bolt and nut are used to connect the handle to the chassis. The side plates that house the electronics were 3D printed before adding 0.5 mm twill carbon fibre plate to achieve the look I was after. This was easy enough to cut using 3D printed templates, scissors and an Exacto knife.

With plenty of room on the chassis for electronics, I added a microcontroller to control an LED strip that encircles the jet inlet at the back of the unit. One of the great things about the ESC I’m using is the onboard Battery Eliminator Circuit (BEC) that puts out a continuous 8 A allowing me to power everything easily. I used a Wemos D1 Mini Pro ESP8266 controller to control the LEDs. Using WLED I can program infinite light sequences via a phone. But let’s face it, I’ll probably just leave them on pink. And while adding RGB to everything can get kind of old, the lights do serve the useful purpose of letting me know that the jet unit is powered on.

To keep with the carbon theme, I used a 90 mm roll wrapped carbon fibre tube as the thrust tube for the jet. This is removable for transport and swappable for different tubes/attachments depending on the job at hand. The thrust tube has a 3D printed removable tip that serves to reduce the diameter and increase velocity.

I have a Kestrel 1000 anemometer that measures wind speed reliably up to 144 km/h. I used this to measure the velocity of the leaf blower and clocked 233 km/h before it almost blew the instrument away! Now, this is well outside of the anemometer’s specifications, but it’s fair to say that the leaf blower seriously blows! It moves about 557 CFM plus of air volume. After a quick garden test to tidy up my lawn clippings, I took away a few thoughts. Firstly, it’s quite dangerous. Loose clothing will enter the jet intake if you’re not careful. Not enough to reach the turbine, but it could happen. Will I add a grill to protect me/the EDF, probably not at this stage (I’ll probably avoid baggy clothing instead). Secondly, it is almost impossible to hold the leaf blower for more than 30 seconds at max. throttle, before my arm starts to weaken from the thrust. I fixed this by adding a second handle, making it even more weapon-like in appearance. I added some stickers as finishing touches and I was all set for the ultimate field test.

By this time, it was about the middle of Autumn, but there aren’t a lot of deciduous trees where I live. So, I headed to a nearby town that had plenty of fallen leaves for me to blow around. I’m not sure if I’ve actually blown leaves with a blower before, but it’s much more fun than lawn clippings! The blower moved leaves en masse and left trails that looked like scorched earth. I blew some leaves around and got the shots I needed for my video. The locals took an interest in what I was doing. I got looks of disgust and awe as I went about my business! 

There’s not a lot I would change if I were to build another one. The throttle knob location was a decision to keep the design clean, but it’s not overly practical. I would probably relocate it or even better, use a trigger instead. I guess it could be ruggedised, but that was never part of my design brief. Maybe more power?!

For anyone that wants to follow along at home, the CAD files are available via the electrosync Patreon page and here is the bill of materials:

  • PPA carbon fiber filled filament (main chassis components).
  • PLA, ABS filament, etc. for other non load bearing parts.
  • Wemotec Midifan Evo 11 Rotor 90 mm EDF
  • Hobbywing Flyfun 110 A HV V5 ESC
  • 2 x 5 cell LiPo alarms
  • Generic servo tester
  • Wemos D1 Mini Pro
  • RGB LED Strip – WS2812B 144 per meter
  • XT90 connectors
  • XT90 series adapter harness
  • 14 gauge silicon wire
  • 2 x 5 cell LiPo batteries (up to 5,000 mAh)
  • 90 mm roll wrapped carbon fibre tube
  • 25 mm roll wrapped carbon fibre tube
  • 0.5 mm carbon fibre twill sheet (or up to 3 mm if you have a means to cut it)
  • 4 x 11.3 mm x 0.47 mm x 1.2 mm extension springs
  • 3 mm stainless steel machine screws (assorted lengths)
  • 3 mm stainless steel nuts
  • 3 mm stainless steel nyloc nuts
  • 3 mm stainless steel flat washers
  • 1 x 4 mm x 25 mm stainless steel machine screw
  • 1 x 4mm stainless steel nut

 

Scroll to top