JordanGrant
Well Known Member
Hello RVers. For years, I've wanted to build an electric RV-6 tug to drag our airplane up the gentle slope into the hangar. I've thought that maybe a retired Odyssey PC680 battery could have enough juice to do the job for an airplane the size of an RV-6, but I wasn't sure. Well, I'm happy to report that it can be done! See below for my version of the battery powered RV tug.
I used this project as my excuse to finally go buy a MIG welder. It's built from welded mild steel: 1" square tubing, 1x1" angle, 1/4" plate, and 16ga sheet for the battery tray. The motors are electric power chair motors sourced from Ebay. The other key bits are a reversible motor controller (basically 2 relays), an ammeter/power display, on/off switch, and DPDT momentary rocker switch for forward/back control.
To make a secure connection between the tug and the airplane, I put a longer axle bolt through the tailwheel with a couple of 1/2" OD bushings on the outside of the tailwheeel mount. You can see in the picture how the slots in the tug connect up to the tailwheel on the bushings. It has been quite secure with this method so far.
For anyone building something like this in the future, one key thing I had to do was robust up the electrics to handle the amperage required to pull the airplane this way. The installed ammeter reads a bit over 70A being pulled by the motors (at the worst point), and my wiring/fuse is designed to carry up to 80A. So plan on designing for at least that level of current.
Just like the airplane, this project is a work in progress. I consider this about Version 4 of the prototype, but the first one that really works well enough that I can share it! I have a few more improvements in mind if I get some time to work on it further.
On this version, so far the limiting factor is mostly just the traction on the wheels. My 7-yr-old son can pull the airplane up the grade into the hangar with it, although he has barely enough weight to push the handle down and make sure the wheels don't slip. I have a great video that I'll try to post later.
Cheers!
I used this project as my excuse to finally go buy a MIG welder. It's built from welded mild steel: 1" square tubing, 1x1" angle, 1/4" plate, and 16ga sheet for the battery tray. The motors are electric power chair motors sourced from Ebay. The other key bits are a reversible motor controller (basically 2 relays), an ammeter/power display, on/off switch, and DPDT momentary rocker switch for forward/back control.
To make a secure connection between the tug and the airplane, I put a longer axle bolt through the tailwheel with a couple of 1/2" OD bushings on the outside of the tailwheeel mount. You can see in the picture how the slots in the tug connect up to the tailwheel on the bushings. It has been quite secure with this method so far.
For anyone building something like this in the future, one key thing I had to do was robust up the electrics to handle the amperage required to pull the airplane this way. The installed ammeter reads a bit over 70A being pulled by the motors (at the worst point), and my wiring/fuse is designed to carry up to 80A. So plan on designing for at least that level of current.
Just like the airplane, this project is a work in progress. I consider this about Version 4 of the prototype, but the first one that really works well enough that I can share it! I have a few more improvements in mind if I get some time to work on it further.
On this version, so far the limiting factor is mostly just the traction on the wheels. My 7-yr-old son can pull the airplane up the grade into the hangar with it, although he has barely enough weight to push the handle down and make sure the wheels don't slip. I have a great video that I'll try to post later.
Cheers!