PT-1445 data

[J_J]

Using the hydraulic calculator, I computed the relationship of HP, GPM, Cu in.

Total HP on my 1445 is 45HP Early 90's

With a 45 HP engine of 3600 RPM, It can only put out 24 GPM @2700 psi

Steering/lift-------4 HP - 2 gpm - .129 cu in

PTO-------------22 HP - 12 gpm - .84 cu in

Tram-------------19 HP - 10.5 gpm - .7 cu in

It does not seem logical, but that is the way the figures came out.

I have replaced the steering and PTO pump, so I know what they are. The steering pump is a Haldex duel rotational gear pump. The PTO pump is a Cessna gear pump. I believe the tram pump is a Cessna also.

If anyone has similar data on their PT, please post.

 

[J_J]

Just some more data, my 1445 uses tires which are 26X12X12.

With a radius of 13 in, the circumference of the tire is 6.8 ft

With a speed of 10 MPH, that equates to 52,800 ft. divide that by 6.8 ft =7764.7, divide that by 60, and you get 129.4 rpm for the wheel motors.

 

[J_J]

On my 1445, the front wheel motors are connected to a tee fitting, and therefore, the front wheel motors both turn from the same source, one line. This gives me reason to believe that from the tram pump, the supply line goes to a tee fitting, one line going to the front, and the other line going to the rear. The front supply line, goes into a tee fitting to the front wheel motors. The back wheel motors, are also connected together with a tee fitting. That means that my two front wheel motors pull at the same time, and the rear wheel motors pull at the same time, unlike some of the other PT models, which turn a left front wheel and a right rear wheel together. My setup may be the old style of wheel motor operation. Don't know if one way is any better than the other. This gives logic to the fact that when I turn one front wheel motor, the other front wheel motor turns, because one wheel motor is acting like a pump. Now ponder this for a while. One of my front wheel motors has to turn in reverse in order to drive the machine forward. I will explain later.

 

[KentT]

Using the hydraulic calculator, I computed the relationship of HP, GPM, Cu in.

Total HP on my 1445 is 45HP Early 90's

With a 45 HP engine of 3600 RPM, It can only put out 24 GPM @2700 psi

Steering/lift-------4 HP - 2 gpm - .129 cu in

PTO-------------22 HP - 12 gpm - .84 cu in

Tram-------------19 HP - 10.5 gpm - .7 cu in

It does not seem logical, but that is the way the figures came out.

I have replaced the steering and PTO pump, so I know what they are. The steering pump is a Haldex duel rotational gear pump. The PTO pump is a Cessna gear pump. I believe the tram pump is a Cessna also.

If anyone has similar data on their PT, please post.

JJ,

In the data above does the .129 cu in indicate the displacement of the steering/lift pump? If not, what does it indicate?

I understand the rest...

 

[Bob999]

On my 1445, the front wheel motors are connected to a tee fitting,

JJ. I believe that you have previously told us that your PT has case drains for the wheel motors. If that is correct then there would be three connections at each wheel motor--supply, return, and case drain. How did you determine that the tee fitting you are referring to is on the supply side and not on the return side?

 

[J_J]

JJ,

In the data above does the .129 cu in indicate the displacement of the steering/lift pump? If not, what does it indicate?

I understand the rest...

Yes sir, that is the displacement of the steering and lift pump.

 

[J_J]

JJ. I believe that you have previously told us that your PT has case drains for the wheel motors. If that is correct then there would be three connections at each wheel motor--supply, return, and case drain. How did you determine that the tee fitting you are referring to is on the supply side and not on the return side?

Yes, my wheel motors have a case drain, and it is a small line on the bottom of the motors. Physically, the line supplying the fluid, is 3/8 line, and could be either, where it comes out the front, goes to a tee, and one line goes to a position on each wheel motor. The correct position dictates how the motor will turn. I could have loosen one of the fillings, and determined the supply line to make it go forward. The trick is to hook up the lines to get both motors to turn forward of backward. If you get it wrong, you just reverse the lines.