In the early days of the North American Eagle, the question of how to steer the car became one of significant concern. After all, how was a driver supposed to take a jet car on wheels, traveling at supersonic speeds, and make it turn left and right? It was a complex problem. Minimum steering capability was required; a total of 3 degrees left to right. Just enough adjustment to hold the car running in a straight line down the course. That’s when the idea of utilizing hydraulics came up; normal mechanical steering simply wouldn’t cut it. This presented another problem. No one on the team was much of a hydraulics expert.
Spokane Community College came to the rescue. Ed flew out to Spokane, giving a presentation on exactly what was needed. The hydraulics class took it on as a project, developing drawings and diagrams for the car. Using a Vickers mechanical pump, which was used on some other aircraft alongside the J-79, the team began to put together a brand new hydraulic system. With up to 3000 psi, it would finally give us the power that we needed to steer the North American Eagle.
Like any other racing team, we constantly find ourselves at the mercy of needing to test new technologies. But we cannot simply take the car down to a local track; a full lakebed is needed to properly test any new developments. That quickly becomes very expensive, meaning that we are limited to making test runs on the car once a year.
When the team went down to the Alvord lakebed in September of 2015, we were excited. It would be our chance to begin the high-speed stages of testing the car, and be a milestone on our way to breaking the world land speed record. That’s when a problem that no one could have predicted came to light. Early in testing, we discovered that the car was pulling to the left, unable to drive in a straight line. In an attempt to correct this problem, a new steering value was ordered overnight by UPS. To the grim dismay of the team, the valve that arrived ended up not fitting correctly. With storms rolling in over the lakebed, soon to enshroud the team in rain, there was little decision but to pack up and go home.
Given a couple of months to fully diagnose the problem, it was discovered that an electrical issue had caused a cavitation of hydraulic fluid to be created, ending up with the wheel constantly being pulled to one side. While correcting this made the problem better, it introduced a new issue that only about 200 psi was being pushed to the steering cylinders, unlike the 1500 psi that it should have been. This meant that there would not be enough force to actually steer the car. It was soon found that a slight back pressure on the other side of the valve was needed to help it properly regulate. Using a restrictor to put about 500 psi back pressure into the line, the steering system began to function flawlessly. It was the answer that the team had been waiting for, for so long.
With a project as complex as the North American Eagle, it often comes down to being able to test the car. We are constantly taking incremental steps up the ladder of speed to make sure that everything done so far functions exactly the way that it should. While having to solve these steering issues has certainly been somewhat of a setback in our plans, it has failed to dull our drive to do something amazing. We are now making plans to run later this year, and hope that you will join us in writing history.