Centurion and knife edges

[Meteor mark 4B]

I've just read an old magazine article where it was advised that the technique for going over a knife edge in a Cent is this: at the foot of the obstacle stop and engage 1st gear, travel up obstacle. Upon going over the top continue down still in first gear.

How dull is that? (Not to mention a helluva strain on the mechanicals!) We were trained to immediately engage 4th gear directly from 1st when clearing the crest, and career down, through the inevitable deep puddle at the bottom, and continue on our way. Much more satisfactory!

[AlienFTM]

And think of the damage you'll do when the unsuspended idler / sprocket (delete as appropriate) smacks into the ground.

 

I was taught to crawl over a knife edge in Scorpion. I say crawl - there has to be a compromise because while the nose is in the air, the soft underbelly is beautifully exposed. Bottom gear, up as quick as you like, find the balance point, roll forward until you engage the reverse slope then floor it.

[Adrian Barrell]

The Cent driver training video advises reaching the balance point then into fourth. The only situation it specifies staying in first is a drop. It does show what happens if you attack the drop too quickly, the idler detaches from its bracket!

[AlienFTM]

I take the point. But a knife edge by its very name suggests a drop on the far side, otherwise it would be a step. The knife edge I was trained on in the dust bowl at Tidworth was just that: about six feet up and another six feet straight down on the other side.

[Adrian Barrell]

The knife edge at Bovvy is about 45 degree up and the same down. That is what I have always thought of as a knife edge though you're right, it's not the best description!

[Meteor mark 4B]

Can't ever recall any damaged idlers, or anything like that. You wouldn't actually engage 4th until you are going downhill. I remember though seeing some Challengers going over the knife edge on the Bovvy training area, and they went up and down in a low gear I thought.

[alan turner (RIP)]

do these views from RAWHS collection help illustrate the point?

[harry7134]

:rolleyes:When I saw the thread title I immediately thought of a " knife edge" about two feet high with steeply sloping sides, made out of concrete, with the top about six inches wide. The object of the exercise was to drive up on the wall and position the Cent so that it balanced on the top. If done properly, the driver should be able to tip the tank like a seesaw by standing at each end, his weight being sufficient to upset the balance.

 

I never saw anything like this in real life, so it is posible that it belongs in the same catergory as the one were a good Cent driver should be able to go up and down the gearbox whilst the tank only travels its own length.

 

One thing I do remember being taught was only to change up when the nose went down, and we practised this by dropping the drivers seat and changing gear by the attitude of the tank, encouraged by the instructor standing behind you with a big stick!!

 

Unfortunately this technique was carried too far when a "sprog" driver was loading his tank onto a loader for the first time, and had just got over the point of balance when he changed up and ran into the transporter cab. His excuse was as above "My instructor said when the nose drops , change up"!:nono:

[tankie589]

It was MUCH more fun at bovvy, TWO knife edges in a row, 1st gear up the first, point of balance, then 5TH down the other side and as far up the next as poss, then straight down to first to climb to the top, then straight up to 5th again. By the way, these aren't six feet high, they're about 12! AND I never saw or heard of a broken front idler.