car driven by compressed air--help needed for this project hello, my name is krishna my final yr project?

Question

"compressed air driven vehicle"ive choosen the prime mover(engine) as pneumatic impact wrench and the fuel is obvious.. compressed air.we have to use a compressed air storage tank .so compressed air will be stored in this tank at 80 bar pressure and the capacity of tank is 200 lt.the total load acting on the vehicle is weight of the vehicle -245 kg (kilo grams);(single )driver wt -80 kg (approx ) ;air tank wt --175 kg;so total wt is --500kg this weight is acting in "y"-axis directionso the total force the vehicle has to overcome for its movement is 500*9.8 =4900kg-m/(sec square ) F=m*g)}this is in y axis direction==4900newtons.the friction force Fcomes intocosideration when the body has to move in "x - axis" direction F=0.15*4900==735N(0.15=coeff of rolling friction).to move i need force >735N.Torque required to rotate the wheel for displacement is735*.20=147N-m(.20 m is rad of wheel).wrench has square drive (1/2") & max torque=400-600N-m (coupled to wheel)can this move my vehicle ??

when in direct coupling with wheel can the vehicle b moved with that torque? the wrench may b coupled to the rear axle and 2-3 gears also may be employed for speed.

Answer 1

From your figures (& assuming you have taken Static Friction), yes.

However, what's the air consumption of the wrench (lt. per second) ? (seems to me when I see these used in garage they always have a dirtly big compressor running ....)

As the wrench uses up the air, the pressure will drop (of course once it start moving, you only have to overcome Rolling Friction)