I ride a motorcycle and the assembled quad just won't fit on the bike.  I have made a few modifications to the Arducopter kit as manufactured by Jani @ Fah Pah.  My mod makes the arms easily detachable with a few more parts. You'll need:

- eight 1/4" spacers (I bought at the local hardware store)

- four bolts similar to the 20mm in the kit

- four wing-nuts or threated spacers that you can grip (for the four bolts above so you can finger tighten them)

 

With the current kit design, the Arms are secured by a two guide bolts at the front to prevent lateral movement, and single metal bolt tying the end of the arm at the center of the Main Frame. But because this bolt attaches to a threaded spacer, and onto the battery holder, it is not easily removed.

 

My Solution: Add a finger-accessible bolt closer to the outside and a pin at the interior.

 

First, with the Arms mounted normally, mark the Arms at the existing frame hole. This is the only hole that is on top of an Arm. Mark all four arms.

 

Create the Pin:  With the Arm removed I added a 1/4"spacer to the existing Arm-to-Battery-mount bolt and tightened. The spacer become the pin and insures the Arm will still fit snugly between the Main Frame boards.  I also added a 1/4"spacer to one of the two front posts and tightened. This keeps top-to-bottom tight, and also pinches a little on the Arm when inserted. i found two spacers (a left and right) to be too tight.  This picture shows the 2 new spacers: On eonteh Battery mount, one at the outside left plastic bolt. You can also see the retaining bolt in its new location (the bright silver bolt) 

 

 

Next I measured, centered and slotted the end of the Arms with a dremel to match the thickness of the battery-mount-bolt spacer. I then drilled a hole in the Arm where I marked the outside frame hole. Repeat for all four Arms. 

 

Now you can mate the slotted Arms to the main frame

 

 

Secure with a new bolt and threaded spacer or wingnut/etc. You'll still need to secure the acrylic GPS/Top ring in the standard fashion.

 

 

I mounted my ESCs on the Arms to simplify the leads - 1 power and 1 servo cable on each and I'm good to go.  Because the ESC is on the Arm, the extra cabling length can be tucked into the Arm's precut slot and tie-wrapped securely.

 

Now I can dis- and re-assemble the Arducopter in about 5 minutes and hit the road.

 

Paul