... I would like to be able to keep the stock specs the winch would have for the maximum pull, for the line speed like you said hydraulics are controllable. It would be nice to be able to quickly spool up the line that is out.
What is the M35A2 line speed?
the pump info i have posted
GPM 13 @1000 RPM
Max Pressure 3500 PSI
I am pretty sure it will run at the same RPM as the engine. The pump bolts to the back of the air compressor. The engine idles around 800 - 850 RPM ...
alright, here's what the stock A3 system performance data would look like with the following assumptions:
- the pump estimates are similar to the stock A3 pump
- 75% worm drive efficiency
- 87% motor efficiency
- 85% pump efficiency
- 1.00:1 pump-to-engine ratio
- 850 rpm engine idle
- 3.003 cid pump
- 10.6 cid motor
- shear pin failure at approximately 250ft-lbs (using Gringletaube's destructive testing data)
- max desired oil velocity of 16 fps (recommended for continous operation systems)
Results:
Max line speed:
at engine idle, you'll have maximum line speeds of
- 14 fpm on a bare drum
- 28 fpm at full drum (5th layer)
at 1000 rpm, you'll have:
- 16.5 fpm bare drum
- 33 fpm full drum
line pull at system pressure (note: motor torque cannot exceed shear pin torque):
- 1006 psi = 10k lbs line pull at bare drum and 5k lbs at full drum (123 ft-lbs at motor)
- 2011 psi = 20k lbs line pull at bare drum and 10k lbs at full drum (247 ft-lbs at motor)
motor speed:
max motor speed to achieve 25 fpm at bare drum is 430 rpm.
valving:
at engine idle speed, the system will flow approximately 11 gpm. however, at an elevated idle of only 1500 rpm, the flow requirements increases to just under 20 gpm. therefore, i'd be sourcing valves for 25+ gpm or no less than 20 gpm. this will give you fast wind-up speed, especially at/near full drum.
Hose / fitting sizing:
minimum cross sectional area of 0.40 sq. in. which is 0.71" diameter.
what this means is that in order to stay under the 16 fps oil velocity, hoses need to be, at a minimum, 3/4" or -12 size. this is for the continuous part of the system. since your pump is not clutched to the engine, the pressure lines from the pump, valve, relief, and any other part of the system that will circulate constantly need to be 3/4". the pressure lines to/from the motor can be smaller since these are only intermittent use. suction line should be in the neighborhood of 1" - 1 1/2" hose (probably closer to 1 1/2", especially if the reservoir is below or far from the pump. if both, then consider larger hose.).
now you need to find a suitable motor. Parker motors should still be available. the one i recommened from NT is also a good fit; it was 9.7 cid. therefore, with a pump displacement of 3.00 cid, then i'd be looking for a motor with a displacement of around 9.5-11.0 cid and be capable of at least 500 rpm and 3000 in/lbs. once you have this selected, then set your system relief pressure in order to limit the line pull of the winch.
rules of thumb - in order to produce a certain line pull:
- larger displacement motors or smaller displacement pumps require less system pressure but result in slower line speeds (or require more engine rpm)
- smaller displacement motors or larger displacement pumps require more system pressure and produce faster line speed (but require less engine rpm)
