Giant 75" scratch built Extra

About a year ago, I decided to make the 200%  FT spitfire. It was an incredible plane, probably one of the best planes I have flown, but one fateful day I did one too many snap rolls and folded the wing. All the electronics were fine except the 5000 6 cell battery that burst into flames. Now, a year later I decided to put that giant 50-60 270 kv motor to good use. I had  designed a smallish 50" Extra a while back that flew great, so I decided to scale that plane up to 150%.

My first challenge was making the 2 piece wing removable while still being strong. I solved that by using a 1x.5 inch wooden spar that is is 60" long. I also used two 750mm carbon fiber rods, and finally a 3/4 dowel that is 4ft long.

The next thing I had to do was find a way to hold the wings together. I did this with velcro and two 3 inch long pieces of wood that screw into the wing to pull the two halves together. This actually worked very well and seems to hold while in the air. While doing this,  I discovered that I had no place to put the battery because the wings were right where I needed the battery to go to get the right CG. To fix this, I glued two pieces of velcro together back to back so I could install the battery on top of the wing.

Now for the fuselage. This part was the hardest. The fuselage shape was very easy. It is just a 5ft long foam box, but getting the wing holes just right was tricky. I had to get them at the exact same place on either side and there couldn't be any up or down angle in the wing,  otherwise it would constantly want to pull up or down a LOT. I know this from past experiences.

Now on to the tail section. I wanted this plane to be 3D capable so I put giant control surfaces on the rudder and elevator. I also didn't want the horizontal stabilizer to snap in a high G maneuver so I put a carbon fiber strip in the center. I used flimsy pushrods so I reinforced them with carbon fiber and BBQ skewers.

The motor mount for the giant Spitfire got cracked in the crash so I had to find something else to mount the motor on. Why not a chunk of 2x4? I asked my self. I went out side, started up the chainsaw, and cut a piece of 2x4 for the motor mount.I used hot glue to glue in the piece of 2x4, and then used 2 screws through the side to help hold it. I also glued some scrap 1/8 inch plywood to the fuselage to make it more rigid.

When the wings and fuselage were done, I started to make it look cool with colored packing tape. I also found a plastic pilot that I glued on the plane.

This was the end result. I think it turned out awesome! if flew great too! I wish it had landing gear, but I didn't have any the right size. It works fine as a hand launch. The plane 3Ds alright, I just can't get it to knife edge.

Specs:

Wingspan:75 in

Fuselage length: 5.5 ft

Weight:  7.9 lbs

Wing Loading: 19oz per square foot.

Motor: 50-60 270kv( Don't get the same motor I got. The magnets fall off like crazy!)

Esc: 100-120 amp

Bec: 10 amp

Servos: 40 gram

Battery: Hyperion split cell 6s 5000 35c

Prop:19x8 APC

WARNING!

Use extreme caution when using giant batteries like this. After my first one exploded, I realised the power of a giant lipo. Whenever I fly this plane, I always have a small fire extinguisher and I also wrap the battery in foam to reduce the risk of a puncture in a crash. I also store them in a fire resistant safe.

Thanks to Barry Katona for these batteries! Be safe, and have fun. Thanks for reading!