An airplane can generate an awful lot of lift tied down in the wind. A Cessna 172 has a Va (maneuvering speed) of 80 knots at 1600 pounds (basically empty), which means that a sudden full-up elevator application at that speed will generate 3.8 (structural load limit) times that 1600 before the wing stall and unloads the airplane and prevents structural failure. I get 6080 pounds of lift. Minus the 1600, we still see nearly 4500 pounds. That's assuming, of course, a high angle of attack to generate that lift, and trikes tend to sit pretty flat. The 172's control lock should be holding the elevator down some to prevent the nose from rising in the wind. If it isn't, the controls are misrigged.
Now, a 170, a taildragger, is in a lot more trouble. It sits a lot closer to its stall AoA, but still a few degrees short of it. It had better be tied down real good.
Many years ago an 85-MPH wind tore though our home airport where I learned to fly. 13 airplanes were torn loose from their moorings and destroyed. Some had used 2x6 boards stuck though an old tire and buried under the surface a foot or so, with the tire sticking out for the tiedown. Those were lifted right out; there was only a few hundred pounds of dirt to lift. Others were five-gallon buckets full of concrete buried a few inches below the surface. The airplanes yanked them out. Others just broke the ropes.
Where I worked before I retired we had a retired powerline lineman come, with his very own powerline truck with a hydraulic auger, and he brought anchors commonly used to anchor powerpole guy wires. A 5/8" or 3/4" thick steel rod about 7 feet long with an 8" spiral steel plate welded to the bottom end, and the top folded over and welded into a loop. That hydraulic auger was replaced with a square steel tube that fit over a square boss on the top of the spiral plate, around the rod, and those rods were screwed in until the loops were just barely clear of the surface. It would take a mighty big wind on any airplane to pull those out. Cost us about $100 apiece installed.
I often used to come across skinny little ropes, or rotting ropes, or cheapo ratchet straps, holding down $150K airplanes. It made no sense. Might as well not bother. It's like duct-taping the doors shut to keep thieves out.
Chains have been known to wreck the airplane. The airplane starts jerking around, and comes up suddenly against the chain as the slack is suddenly gone. Torn-out tiedown rings, damaged spars and/or struts. Not good at all.
