HST in larger tractors?

JATO_RaT · Feb 6, 2002

Dick, the driverless Kubota, is that considered unsafe? Its still the way we pick up rocks. Idle, 1st gear and run like mad throwing rocks in the front bucket. A few course corrections is about all it took. Amazing how slow idle and first are but how fast it is when your running around throwing rocks in the bucket. We still do some coffe can fertilizing on the orchard. In fact 46 tons just came in yesterday. Thats all applied by hand believe it or not. It works wonders though as it is just the right mix according to the company that provides it based on the soil samples they get from us. Anyway, the orchard is still sprayed by tractor although I don't think its all that scientific and just anything from an old station wagon to a tractor could pull it. The L48 is more shiny bare steel now then anything as I have been moving hundreds of yards of my hill. Its mostly DG (decomposed granite) which gives me tons of traction and cuts beautifully. Giving it a good work out. I'm ready to give it the 50 hour work over. 48 qts. of hydraulic fluid to change as well as engine oil and axles. Rat...

rbargeron · Feb 6, 2002

My custom-mix orchard fertilizer was something like 15-0-20-2-3-2-2 based on soil and leaf samples. And we were big into integrated pest management - using just the minimum insecticide and timed the applications to trap captures so it didn't wipe out the beneficial predator populations.

Now that I think about it, HST would have been a nightmare - with sprayer tied to pto rpm, an accurate ground speed indicator would be a must - or there could be a crop disaster. Depending on which regulator was being applied, just a small speed error would over-thin them, change the shape of the calyx, over-accelerate the ripening, or alter their Controlled Atmosphere storage life. Do HST's have a ground speedometer? If not I'm afraid they are useless for spraying an orchard. My earlier post is wrong - HST wouldn't work without a ground speedometer.

Egon · Feb 7, 2002

Driverless tractor:

There are times when a draft horse is invaluable.

Egon

JATO_RaT · Feb 7, 2002

Dick, I have never had the occasion or need for a tractor to have a super precise ground speed. The hydrostatic transmission on Kubotas doesn't so much slip as it either can or it can't roll the tractor. As soon as a hill is encountered for example, rather then slip the engine loads down, RPM's obviously drop and the choice is either to increase RPM's or decrease the fluid flow via the HST pedal. The only time I notice "slippage" is when I go into a pile of dirt with the loader where I cannot push the bucket in any further. One of three things happens,
1. the engine stalls if I don't back off on the hydrostatic control pedal.
2. The wheels spin so I load the front bucket for added traction
3. I drop down to the next lower of the 3 speeds.

Very rarely have I found that adding engine RPM does much since I'm typically at 1900 to 2000 RPM already. The term slippage may really not be all that accurate as I think much the same scenario happens with my geared International. While I most certainly agree that a hydrostatic transmission is of limited benefit where the use is simply straight forward movement and in some ways cumbersome, I find that for the ultimate in mobility whether it be loader work, mowing etc, its a very tough transmission to beat.
By the way, I still enjoy climbing on the L4850, one of the nicest tractors I have ever used period. Rat...