Microtractor Part Sourcing

Overview
Part Sourcing for the Microtractor. Much design work has been merged into the Power Cube.



Sourcing

 * from here
 * 14 hp 2 cylinder engine no starter $975
 * |65%3A15|39%3A1|240%3A1318 11 hp 1 cylinder generator $899.00
 * |65%3A15|39%3A1|240%3A1318 13 hp 1 cylinder silent $1300
 * |65%3A15|39%3A1|240%3A1318 13 hp $695 GAS
 * |65%3A1|39%3A1|240%3A1318 23 hp water cooled diesel engine with radiator $1000 - $1349
 * |65%3A1|39%3A1|240%3A1308 62 hp 4 cylinder tractor $1828
 * |65%3A1|39%3A1|240%3A1318 65 hp 4 cylinder tractor $710
 * |65%3A1|39%3A1|240%3A1318 40 hp 3 cylinder $1500 - $2300
 * |65%3A1|39%3A1|240%3A1318 35 hp 3 cylinder tractor $1185
 * 90 hp 4 cylinder diesel 2000 vw beetle $2000
 * |65%3A1|39%3A1|240%3A1318 11 hp 1 cylinder $400


 * more from here


 * |65%3A1|39%3A1|240%3A1318 13.7 hp 2 cylinder $666
 * Perkins 402C 13.7hp 2 cylinder Same as above, asked for quote 3/5/09 talked to jeff

Power Cube (MicroTrac engine cube) Details



 * The coupler halves and spider are shown in the pictures, from McMaster Carr page 1157

Pump

 * From - Pumping = 1 Hp = 1 GPM x 1500 Psi - (linear relationship i.e. 2 GPM @ 1500 Psi = 2 Hp)
 * For the above pump, 14.2 gpm with 3000 psi indicates 28.4 hp requirement
 * Hp to drive hydraulic pump = Psi x GPM / 1714
 * For the above .97 cu in pump, 3000*14.2/1714 = 24 hp
 * If we run at 2200 psi => 18 hp required
 * For .86 cu in pump, need 3000*12.6/1714 = 22 hp
 * For the same with 2500 psi, 18.3 hp

Power Available

 * Assuming 85% pump efficiency, we have 17.5*.85=14.8 hp power available to the machine

Wheel Motor Calculations

 * 32 cu in wheel motor: 20 gpm, 5170 in lb torque, 145 rpm
 * Using 12 gpm, 5170 in lb torque, at 87 rpm - uses 7 hp of the engine

Spider Torque Rating
The Hytrel coupler spider has a 401 in lb torque rating. This is at 3600 rpm. If this pump is driving a hydraulic motor at 87 rpm (wheel motor at 12 gpm fluid flow, at its rated torque), what would be the maximum torque that the 87 rpm could have? 401*3600/87 = 16600 in lb. That is well within the 5130 in lb torque of the wheel motor. Coupler spider will hold up.

Engine
Power Cube

Wheels



 * one set of drive wheels in the middle balanced with the engine so the Microtrac can be rotated easily, with a motor on the side
 * doubled up for traction
 * have support wheels on the back sides so it doesn't tip easily
 * drive wheels the same as lifetrac, 30" high 10" wide

Resource Map
Reviewers: Coupler info:
 * http://www.tractorbynet.com/forums/build-yourself/140170-homemade-modular-hydraulic-engine.html
 * No response as of 4.28.09
 * http://forums.hydraulicspneumatics.com/eve/forums?a=tpc&s=4721063911&f=8641063911&m=74110526&r=74110526#74110526
 * Useful response, including hydraulics primer, Mr. Hanson's contact as a consultant, etc.
 * The response claims need for 30 hp if we want 15 gpm at 2200 psi. We have 12 gpm at 2500 psi.
 * CadTrac uses 16 gpm pump and 18 hp engine, at 2000 psi for 1/2 of the flow (to wheels) and 1000 psi to rest of flow (loader)
 * http://www.lovejoy-inc.com/uploadedFiles/Catalogs/jw.pdf
 * http://www.ohiobelting.com/pdfs/lovejoycplg.pdf