According to the pilot in the experimental, amateur-built airplane, during landing, the RV-4 bounced, and he added power.
The airplane landed on the runway, but the left side “dropped” to the ground.
The airplane ran off the left side of the runway at the airport in Caldwell, Idaho, where it came to rest.
The airplane sustained substantial damage to the horizontal stabilizer.
The FAA aviation safety inspector who examined the airplane reported that the weld on the left main landing gear axle support strut had failed with some signs of overload.
Probable cause: The failure of the weld on the airplane’s left main landing gear axle support strut during landing, which resulted in a loss of directional control.
NTSB Identification: GAA18CA203
This April 2018 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
An Rv-4 landing gear leg is a tapered rod wittman style gear where the axle is integral to the gear. The whole assembly is machined then axle is formed by bending the the rod in a heated condition after which the whole assembly is heat treated. NO WELDING ! Not sure what airplane the NTSB was investigating.
Should say TIG
If you’re not a skilled welder using oxy-acetelene or STIGMA get some extra feet of tubing of the same type and size and practice . test each and every weld to destruction.
Take a hands-on class too.
You seem to be implying that the builder did not do an acceptable job of welding the landing gear. It so happens that since the RV-4 days all Van’s landing gears have been supplied by Harmon Lange and are included in the kits already completed. This is to insure that the mounting pads are machined to half a thousandth of an inch and that the units are properly heat treated after welding. See the December, 1999 issue of Sport Aviation for more information.