I built a couple of them some way better than others
my best was all used wood
from demos, construction job (an old pole barn)
8x8" x 20' A-frame on the ends all sanded & clear coated
cemented/concrete in place
Simpson strong ties/bolts connecting everything up top
16" auger used for the piers/cardboard tubes
like 4' down IIRC at an 60*/30* angle
with an old 8x16" x 20' glulam for the beam/hangers
d-ring & shackles for bindings with swivels
so the 1-1/2" rope
or 2" straps (lifting or tow straps) would NOT get all twisted up
leather seats 6x24" Lisa sewed in triangles connections on the ends
(she crafted horse tack/gear too)
it was almost 15' high (IIRC)
dangerous as ****
you could swing from 1 of 2 ropes in the center
reg knotted 1-1/2" rope swing
with a plastic coated 10# disc weight at the bottom
or a tire swing, with a 3 x 1"x 4' straps triangulated anchors
to a single rope & swivels anchor at the top
or the 1 of 2 swings with leather seats on either side
it was great, kids loved
I'd go out & swing on it a lot too
all their friends loved it
you could get to a tree off the rope swing,
it was sketchy as ****,
my brother Tim broke his arm falling off it
(not the sharpest tool in the shed)
trying it out, not a great start
we did get some used foam pads/liners from a wrestling center
like 20x20' from the HS for padding on one side,
when they got new ones
put it down on a lil' hill by the tree behind it
kids liked to bail off at like 6'-8' off the ground
wish I had a photos
I'll have to look thru the old slides & Polaroids
it was still up when I moved in 2007
it was up since 1997 when I 1st moved there
I used it a gantry with a chain fall, lifting heavy stuff
out of my truck/s Jeeps or off trailers etc., a few times too
@747mopar
good luck sounds like a cool swing
you're building for your kids