FPV Twin Engine Cargo Snow Plane! How To w/ Videos

How to build a very simple twin engine FPV (or los) plane.

I use it as a snow plane, belly landing it. It’s a great platform for FPV as the props are on the wings, so they are protected and out of the shot. The underbelly curves upward toward the nose to keep the nose from digging into the snow.

This plane is very simple and cheap.  Without eletronics it cost about $8 to make. 

Watch the video to see how to build it, the first 5 minutes shows how to build, the next 10 minutes show the electronics, programming and some tips, the last few minutes is a short onboard gopro video.

Need to build: Turnigy 28/26-10 1400KVmotors or similar (x2), 7x5 props (x2), 30-40 amp esc, 2200 battery (at least 20c) (x2), orange 710 reviever, HXT 900 servos (x4) (5 if you add a bomb drop or servo pan)

Tips I use a sidewalk stake (bright orange and reflective) to strengthen the wing on the 50 inch plane I made. I used a 2mm CF rod on the 40 inch.  I use surveyers markers as control rods, a pack of 50 cost $3 or so, just remove the flags. Both these items can be bought at hardware stores.  The windshield is made ouf of clear plastic trash, like what eletronics are often sold in.  The motor mounts I 3D printed. I am happy to share the file if you want it. Otherwise just get some metal angled brackets at the hardware store, or even use a wooden wedge, or stick mount. 

Scale: You can scale it from a 40 inch wingspan up to 60 inches or more.  If you want it smaller than 40 inches I suggest using only 1 battery and making the fuse 3x3 not 5x5. Its very sporty at 40 inches, and has a high payload capacity at 50 or more inches. The downside of the 40 inch version is with 4400mah of batteries it had a bad glide slope, made worse with FPV gear and cameras. 

The dimensions for a 60* inch wingspan:

*can be cut down to 50 inches or less

Fuse: 5x5x30 rectangle, cut off the back wedge.

Nose: 5x5 by about 10 inches long

Wings: Cut 2 pieces of foam to 30x15.  Bend at 8 inches. 

>Then remove 7x30 inches of the paper, this will make bending the top of the wing easier. Leave the other 8x30 covered, this will be the bottom of the wing

>Ailerons should be 11 or 12 inches wide, 2 inches “deep”

Tail Feathers: Horizontal stab is 8 inches tapering to 16inches wide, vertical stab 10,10 cut to a triangle

COG: 2 inches from leading edge (on any 8 inch chord wing)

Note: I suggest placing the tail servos near the control surfaces. Mine are located near the wing on my 60inch wingspan plane as I plan to add a drop door and wanted to make sure they would not snag on parachutes or anything I am dropping. I had to add guide tubes to keep the servo wires from bending.

I programmed the ailerons to also be flaps or “flaperons”, to help it take off and land. It also has differential thrust.

Programming for Differential thrust: Add 20% of rudder to both throttle channels.  (can be set to activate on a switch if you want)

Programming for Flaperons: Add 35% to ailerons at ID1 and 60% at ID2 to both ailerons channels

(if anything goes the opposite way just try subtract instead of adding)

Note: If using 2 different ESC try moving the start point back in your controller of the channel of the ESC that spools up first.  Mess around until they start at the same time. 

 40 inch version:

Here are some stills from the video that show key steps (60 inch wingspan, can be cut down to 50 or less):

(total length is 8 inches by 60 inches) The wing bottom is 8 inches, the top is 7 inches (with paper removed on inside) once curved this leaves about 2 inches of flat area on the trailing edge for ailerons.  Place the stake (or CF rod) about 2 inches from leading edge, secure it with layers of foam. 

 You should install the wing about 4 inches from the fuse-nose joint (about 14 inches from nose tip).  Move it forward an inch if you plan to use really big batteries and cameras, and back an inch if you plan to never use FPV gear and/or small batts.  This will make getting the COG (center of gravity)correct easier.  The COG should be 2 inches from the leading edge of the wing.  

To test the COG place your fingers 2 inches from leading edge of the wing (on left and right underside) and the plane should balance on your finger tips. 

I covered the entire plane in packing tape. Use low quality lightweight tape for the top of the plane and heavy weight on the bottom. I used a small amount of duct and eletrical tapes to make some patterns to help identify it in the air. 

Happy Flying :D