Ercoupe/Aircoupe gust lock
have no professional or expert qualifications of any kind.
My Ercoupe did not have any gust lock provision. So, I used a simple light rope tied between the two yokes.
To control the elevator, I also passed the rope over the instrument panel-firewall brace as well as through the two yokes. This held the elevator full down.
If the wind was from the rear, the wind would push the elevator down, pushing the tail down tilting the plane back and so the wind would press on the top of the wings, holding the plane down.
If the wind was from the front, the wind would lift the tail as much as allowed by the tail tie down or if the tail tie-down failed. By holding the elevator in a position that would only trim way faster than 150 mph, the plane will not lift until the wind gets to that prodigious speed. (Note: also push the trim tab to the high speed position.)
We had a wind storm at our rural Iowa airfield. My Coupe was in an open T-hangar and none of the planes there were damaged. The buildings weren’t damaged much.
Of the planes tied outside, only another Ercoupe survived in spite of having broken all of its tie down ropes. The owner had left the trim set to the highest speed. So, when the wind blew stronger, the tail stayed high because it wasn’t up to its trimmed flying speed. The airport owner saw this before he ducked into the tornado shelter – he saw the Ercoupe bouncing and weather vaning into the wind. After the storm, the Ercoupe was sitting happily, turned way around from its starting position. It has kept its nose into the wind even as the wind changed direction.
When the other planes broke their tie downs, they were already at an airspeed faster than their trim speed and they lifted off – for a few seconds - till they crashed, sometimes into other aircraft.
I say all that to say this: Set your trim to max speed when you park the plane, every time. A useful gust lock (at least for a field expedient) is to tie a rope from the instrument panel support bracket and between to two control yokes.