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The LawnDart - $1 EDF


Well-known member
It's basically a big paper airplane, and flies like one too!

Build is pretty simple:
1 - measure and draw a vertical reference line down the middle (long-way) of DTFB sheet.
2 - use a straight edge and mark a score line from the middle of the top to each lower corner. This will be the simple outline, but DO NOT cut through - just score.
3 - Flip the sheet over and run another vertical reference line down the middle.
4 - crack the score cut (1 at a time) and fold over. There will be a triangle that goes over the center reference line - use a straight-edge and mark where the center line intersects that piece. Unfold and cut that end triangle off. Repeat for the other side. You should be able to fold both sides over and get the delta shape now, trim if necessary.
5 - use some wood glue and glue both sides down, then run a piece of packing tape over it.
6. I just kinda eye-balled where the EDF went. Depending what fan you are using, just do the same - the "mouth" of mine is pretty close (maybe 1/2 inch) from where the foam sheet doubles over. Trace, cut, trim to get it to fit.
7 - Cut out Elevons - I left 3/4 of an inch between the exhaust opening and where I cut them. They don't have to be very big, maybe 1" x whatever the length is going to the outer edge of the delta
8 - hinge them like you would any other foam, and reinforce back side with some packing tape.
9 - I mounted my servo's as far forward as the longest pair of control rods I had - again, just eyeball it.
10 - I used some scrabs and made a small wedge for the bottom to protect the fan on landings. It's about 8" long and is 2 sheets of foam wide. This also gives a good grip for throwing it on takeoff.
10.5 - Use some scrap and make some small winglet's - I cut the corners of the delta off square and glued them on - use toothpicks through into the foam to give them some rigidity
11 - mount your EDF - I just used some hotglue since it's easy to clean off down the road.
12 - wire everything up, add some velcro to the nose for holding the battery, and a good battery strap
13 - trim control surfaces and go fly.

Build took in total about 2 hours

Mine uses 2x 9G cheap blue servo's, a 70mm EDF, 40A ESC and flies fine on 3S 2200mAH and 4S 2150mAH (better on 4S)

I'll shoot some video this week.


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