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Putting ESTA through her paces
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by Martin Hayes LAST WEEK in CM I reported on a significant new development from Ford — an electronically controlled semi-automatic trans mission called ESTA (for Electronically Synchronized Transmission Assembly). I said then that it was difficult to assess the new device's full potential until I had had more experience of it in typical operating conditions, I have now had an exclusive opportunity to try ESTA — fitted to a 45-seat, Alexanderbodied Ford R1014 bus chassis — over a 21A-hour, 130 km (80-mile) route.
In general, my initial praise and reservations about ESTA published last week seem justified after a longer spell at the wheel. Perhaps the most damaging statement I can make about ESTA is that after 21/2 hours of driving I had not fully mastered the correct technique for making perfect changes. By that time I had mad'e.a good gear change more than once in every possible combination but that happened by no means every time.
There is, of course, no difficulty about making down changes — the, minicomputer works out all that and takes control away from a possibly insensitive driver. In fact it was changing up in the lower gears that I found most difficult. To get it just right the throttle pedal needs easing back at precisely the right moment. To start with I was lifting right off the throttle as I moved the selector lever through the gate. This produced plenty of jerks. The correct technique, which I finally got near to perfection, is to ease back on the throttle slightly just after the selector lever has been firmly located in the next gear position. Timed correctly, this produced a gear change which was imperceptible apart from the change in engine note.
As I have already said, down changes were simple. In fact, although they were controlled electronically there was still plenty of satisfaction left and I found that I was going down through the box just for the pleasure of it. On a more serious note, of course, this was good for smooth, controlled braking. On the approach to roundabouts, for example, the technique I developed was to place my right foot gently on the brake pedal and run down 'through the gearbox. In this way I was always in just the right gear to pull away again if a suitable opportunity arose.
Once or twice on the run I caught the box out by jumping, say from 4th to 2nd when near stationary for a quick getaway. Just occasionally I applied the throttle too early and got a "neutral" position until the gear dropped in with quite a jerk. On the test it rained continuously but only once during a fast downchange from 5th to 4th at high speed was there any suggestion of the back wheels locking. I do not think this is a serious problem the vehicle was empty — but it might be one needing attention on ice or snow.
The other point about down changes is altogether more important and will not be fully resolved until ESTA has been in service for some time. This is The posibility of arriving at a neutral position when going down hill. My route took me through Chesham which is well known for steep hills. About half way down one of these hills — average . gradient about I in I 1 — I decided to change down, from 4th to 3rd. Because I was travelling rather too fast the gear only just engaged and I was very near the maximum road speed for that gear. (The transmission, it should be remembered, is designed to prevent engine overspeeding by overriding the selector, boosting the engine to maximum governed rpm and waiting until the road speed falls to the correct level before engaging a gear.) It occurred to me, coming down that Chesham hill, that the situation would have been potentially difficult had the gear not engaged. Had I been descending the same hill when the brakes failed there would have:been no recourse to the transmission for assistance. Now I realize that ESTA is not alone among semiand fully-automatic transmissions in this trait, but it is one that some operators may find worthy of consideration.
While considering performance on hills it is perhaps worth mentioning hill starts. These I accomplished quite easily, it being simple to feel the clutch disengaging through the throttle pedal. One point that needs remembering — particularly to those used to torque converter transmissions -is that no drive is engaged until the throttle is applied. Thus even on minor gradients the vehicle will roll back unless the throttle is open and the clutch slipping. In practice I found it all too easy to sit on hills holding the vehicle on the throttle which, if continued for any length of time, would obviously have disastrous results for the clutch. This is clearly a point which will need special attention when training drivers to use ESTA.
I was particularly interested to see how easy ESTA was to use and abuse when manoeuvring the bus at low speeds. This is where much of the damage to transmissions is caused and, equally, where too much obstruction in the form of inhibitors can lead to frustrating delays. I had already seen how well the device protects reverse gear from being damaged. Despite several attempts this would not engage until the bus had come to a complete halt. However, going into first from reverse produced some unhealthy jolts from the transmission, though the gear did not engage until the bus had halted. During these manoeuvring tests I discovered that the clutch disengages at about 3-5 km/h (2-3 mph), which had not been easy to detect on the open road.
I have deliberately tried in this assessment to find weaknesses in the ESTA system. None of these problems -driver tuition, clutch slipping or downhill runaway — seems inherently insoluble. Driver training will evidently need close scrutiny but many bus operators may well prefer the fully automatic version of ESTA