Go Big or Go Home! 4 Motor Scratch Build!

I have been building the Swappable series planes for a while now and had a bunch of parts laying around that weren't being used.  After seeing the FT Cruiser, my friend (RescueLoadMaster a.k.a. Ian) and I had an idea to do a 4-motor plane just to see if we could. We have both only been in the RC hobby for a little over a year, but after an evening of beer soaked initial planning this idea was born. I had four motors and ESC's sitting around from failed quadcopter attempts, so we tried to base it off of the B-17 but it kind of came out looking like a mix between a B-17 and C-130.

We started with the fuselage, which is an entire sheet of foam board that is scored and rolled to give it that rounded shape.

The wings are made like those on the Bloody Wonder but are made from two sheets of foam board and have a slightl forward taper on the trailing edge. We both have built the FT Bloody Wonder and love how stable the wing is. They're joined like the wings on the FT3D with a 4 inch gap in the middle for a little added wingspan and to allow room for the enormous wiring harness. The wing was by far the hardest part to make, largely because all of the electroncs are ran through the wing. To run the electronics we tied a metal nut to a piece of kite string and used a magnet to route it through the wings and then pulled our wires through. Our power wires are attached to all of the motors using 3.5mm bullet connectors so we can unplug and change things as needed.

There is also a nose cone to add a little length and area for future FPV equipment.

Once it's completed, it's three pieces that can be assembled easily at the flying field. All the pieces are held together with four BBQ skewers, two short ones hold the back of the wing in the fuselage and two long ones that connect the wing, fuselage and nose cone.  We glued light ply to all of the areas where BBQ skewers connected the pieces together to keep the foam from pulling apart.

Once assembled, it has a 64" wingspan, 42" length, and we got the CG perfectly aligned with the spar.  The ailerons measure 15"x2", the flaps are 12"x2", the elevator is 18"x2", and the rudder is 8"x2".  We figured is was better to go big with the control surfaces and if we needed to, we could always dial down the rates. The landing gear are the FT Cruiser design using 1/8th" wire.

The electronics are 4 DT750 Hextronic motors turning 8x6 props with 4 25A Turnigy Plush ESC's, there is a total of 7 servos that are all 9grams and we had 2 3S 2200ma Turnigy Nano-Tech batteries powering it all. We were flying with a Turnigy 9X with the FrSky module installed. It weighs about 2100grams and from what we could tell had about 1650grams of thrust. It's got ailerons, flaps, rudder, elevator, and steerable tail wheel mixed in with the rudder that is run by it's own servo. The power pods were the FT Swappable Power Pods only cut down to about half size as to not interfer with the control surfaces.

When it came time to maiden this monster, it only had about 5 feet of ground roll before it lifted off the ground.  Once in the air, it flew like a dream.  Believe it or not, we did not have to trim this baby at all.  In our minds it could not have flown better.