Ranger Retrocenter (https://twitter.com/retrocenter) has revealed a pic of Jason David Frank in a green cockpit that hasn't been seen on the show.
This pic has rotated a lot of the first cast in an unknown cockpit and it has the same triangle on the front. Some are thinking it might've been the first cockpit for Thunder Megazord that was never used before and looks a lot like the one for Tommy. It is hard to tell but maybe the front is green even though it looks blue in the pic. Also, the back looks black but maybe it was green. This could be the same cockpit. Ranger Retrocenter had uncovered a call sheet saying they were shooting footage of the Thunder Megazord cockpit with the six Rangers including Tommy.
Here is the cockpit we did get and the triangle is yellow. It is possible they changed it. It is unknown why this change was made. According to stunt coordinator, Jeff P. says this footage only took a day to film.
Curious enough Boom Comics has the main center triangle as red and not yellow.