This was supposed to be more for adults, but the kids absolutely love it. The total span is 151′ with a ride length of 140′. Total drop is 8′ from end to end, resulting in a fairly fast ride. I decided to purchase a kit because it was cheaper than buying all the parts separately (almost always the case). You can get this kit at www.ziplinegear.com. After extensive searching and reviews, the Viper kit proved to be the best value. You also need to rent the tensioning kit as recommended. I did not. Big mistake, big, huge. I got it all working anyway after much improvising.
I built a ladder out of 16′ 2×4’s with 1.125″ holes bored 1″ deep every 12″. I cut 1″ EMT into 16-19.875″ pieces and sharpened the ends with my grinder to make them easier to install. Installation consisted of pounding all the rungs into one 2×4 with a mallet and wood block. I then pounded the other 2×4 in place working from one end to the other and back again until the EMT was embedded 1″ into each 2×4. 10 screws were sunk into the back side of the ladder into the 2×4 and EMT to keep the rungs from eventually falling out. Mounting brackets were made from 1″ steel bar and mounted to prevent sway and twisting. Nothing touches the ground so the whole system can sway with the tree. The ladder is very solid and cost about $65 with mounts. The ladder is perfectly plumb. I promise.
The platform was also designed to have no contact with the ground. I did not want to clutter up the play area, so I kept everything up high. The platform is at 11′ and connected to the tree with several lag screws and angle braces. It is approximately 4×4 and holds at least 200 lbs. Everything was stained red oak to match the playground and resist the Oklahoma weather.