Thursday, August 11, 2011

The Merry Bee: Riding the String

Riding the String
By Rob Watson

All mechanical devices have development problems. This is especially true when the developer is inexperienced and in a hurry to get things done. In this case "hurry" led to some good news and some bad news. The good news was that the idea to make the clutch hydraulic saved me from figuring out the complex mechanical linkage to make the clutch work. Just mount a hydraulic master cylinder next to the brake master cylinder, screw a slave cylinder to the transmission and you are done. (for the nitpickers, there is a hydraulic line and an actuation rod as well) The bad news was a string attached to the throttle... (actually a length of electrical wire) that could be passed to the control of another person. You made the Bee go faster by pulling the string(wire). Because there was a very limited exhaust system installed, you could also create a great deal of noise by pulling the string.

The a few days before, I had discovered the break and clutch master cylinders both were not working properly: no breaks, no clutch. I took them apart, rebuilt them with new parts, and readjusted them and let them set. On a Sunday I decided to test them out to insure there were no more problems. As I went cruising down the road south of Big Lake in Arkansas, I encountered Jimmy. We chatted for a bit and Jimmy decided he wanted to go for a ride in the Bee.

As we toodled on down the road (I liked to drive about 50) Jimmy saw how the throttle worked and asked if he could operate it. Presumably, he was enamored with the increased speed and increased noise associated with jerking on the string, 'cause he was working it over.

You may recall that road is mostly straight on the east end and passes through unoccupied areas. There, speed and noise were not a problem. The west end is curved and occupied.  As we approached the curves I tried to get Jimmy to stop jerking on the string. Apparently, he was otherwise occupied to the point of ignoring me. No problem, thinks I. Engage the clutch, depress the breaks. Still noisy but we would slow down. Nope, nope, nope!!!

When I depressed the clutch it went, easily, all the way to the floor and stuck there, without disengaging the transmission. I immediately depressed the break. It slipped easily to the floor and stuck there without engaging the breaks. No Clutch, No Breaks, and a madman jerking on the throttle.

Fortunately, after a few seconds of pure terror, I remembered there is always an option of last resort, on automobiles it is the ignition switch. I turned the key as the Bee zipped through a series of S curves with Lake on one side and big trees on the other. ( it has always amazed me that, in the movies, someone is driving a car that goes out of control and they never, never turn off the ignition... But that is the movies)

When the engine died, while roaring down the road and the madman jerking furiously on the throttle, Jimmy looked at me with a look of pure puzzlement. When the Bee came to a complete stop, I demonstrated to my puzzled passenger that neither the break nor the clutch were working. He did not faint or die of fright...  it was a near thing either way, I am sure.

If you get the chance, ask Jimmy to tell the story. His is a much more dramatic version.

PS: at the risk of ruining a perfectly good mystery, The problem turned out to be: I had used the wrong kind of hydraulic fluid. It caused all the rubber parts to swell up and stick... once depressed they leaked around the seals and would not return to the original position. The lesson from this: if the book says use DOT 3 hydraulic fluid, use DOT 3 hydraulic fluid, or you may end up "riding the string" and need to remember about the ignition switch.

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