PC1800 Front Shovel (1/12)

[supraman]

I have been following your thread with interest . I am using roughly the same size gear as you . I think from memory you are using a 2.2cc pump and an open centre spool valve. I am using a 1.6cc pump as i only have 4 cyls on 1/10 scale .

I was interested to see how you went with the open center valve as i was going to use the same , but i read they are not good for uses other than hydraulic motors- mainly due to sealing around center . I liked the fact the pressure is not present unless using a control , but can not get my head around how you get pressure on one vale while the other 2 are -open to tank? -

I noticed you get some creep on the other cyls ,but maybe that is because you have removed the detents and it is hard to find the exact center ?

Strangely after watching your video i think i may go with closed centre spools and use the throttle mixing in the radio to increase pump rpm when a channel is used ( ie -- theoretical numbers --%50 rpm for main boom=2x cyls , %20 for the arm and %20 for the bucket ) . Which would also turn the pump off when no hydraulics are used . Maybe this is common , but i can not find videos where they do this -maybe there is a reason and i will find out through trial and error or maybe some on on here could explain is this is a bad idea and save me time ?

I am looking forward to seeing you progress with this model as you already look like it will be very well made ,, all the best .

[DADSGARAGE]

Yes the pump I'm using is about 2.2cc/rev. The open center valve body can be hard to figure out how the open center works without actually being able to mess around with one....but it does work!! LOL
I changed this valve body to a closed center by simply installing a "closed center plug" which is on the right hand side in the photo. So if you use an open center valve be sure it can be changed to a closed center when the proper "plug" is installed, this will give you the option to go either way, closed or open. The valve body and the matching center plug is from princess auto.

Yes you did see the cylinders creep...lol.... and yes it is because I didn't get the controls centered , the control return springs are removed

Using the valve with a closed center didn't really improve anything, only slightly more responsive due to the constant high pressure, but the pump motor is always under load draining the batterys even when the controls are in neutral, I'm hoping to try and avoid using an ESC on the pump motor so I will most likely run this with the open center...time will tell.

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[DADSGARAGE]

Started building the frame that hold the hydraulics etc. It will also help support the 1/4" ALM. floor, and once the body panels are installed it should be nice and solid....

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This will be the general arrangement of everything....valve body, pump, motor and servo tray all in one frame or a least thats the plan for now...LOL

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[DADSGARAGE]

More work done on the frame....servo tray is finished and installed

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The 1/4" shaft under the servo tray will be the pivot point of the spring loaded belt tensioner for the small vbelt pump drive. Throwing around the idea of adding a sevo to the tensioner shaft and being able to disengage the belt, the motor would continue to turn but the pump would stop, decreasing the amp draw and adding a little bit of battery time....really trying to avoid using an ESC on the pump motor if possible....just a thought

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Thanks for looking....