To address the issue with my wiring as some of you have commented on. The picture of my first Jerry rig is no different than the way 30 to 50 amp adapters are wired. I am jumping one 110 leg to the two hot legs of the 50 amp plug. This does not give 50 service. Contrary to what I might have suggested this does NOT give 240 between the two legs either.
What I have done, and it is working, is I kept the 50 amp 240 household service receptacal wired as is. I have an 10 ga 3 wired extension cord with the one end having the 3 prong female 50 amp plug. I wired in a 50 amp RV plug with the black and white wired to the two hot legs and dropped the neutral. I kept the ground the same. The common is not necessarily needed since this is AC power.
If I was going to permanently wired in 50 amp RV service I would wire in a neutral for safety precautions.