Question

Give some typical numbers for tire pressures generally used in Boeing 707 and Boeing 747 planes. For their main assembly calculate and draw the tire imprint area for circular and rectangular shapes.

Type of Plane	Tire Pressure (psi)
Boeing 707-320C	180
Boeing 707-120B	170
Boeing 747	204

Boeing 707-320C, Maximum load on each main assembly = 157000 lb (4 Tire)

Boeing 707-120B, Maximum load on each main assembly = 120000 lb (4 Tire)

Boeing 747, Maximum load on each main assembly = 166500 lb (8 Tire)

Answer 1

The tyre pressure generally ued in boeing 707 and 747 is 200 psi.

Calculation for Boeing 707 320C :

Load on each tyre= 157000/4 = 39250 lbs

Area of imprint of each tyre = 39250/180 = 218.056 in²

Circular Radius = (Area/3.14)^0.5 = 8.33 in

Square side = (Area)^0.5= 14.77 in

Calculation for Boeing 707 120B :

Load on each tyre = 120000/4 = 30000 lbs

Area of imprint of each tyre = 30000/170 = 176.47 in²

Circular Radius =(Area/3.14)^0.5 = 7.495 in

Square Side = (Area)^0.5 = 13.28 in

Calculation for Boeing 747 :

Load on each tyre = 166500/8 = 20812.5 lbs

Area of imprint of each tyre = 20812.5/204 = 102.022 in²​​​​​​​

Circular Radius = (Area/3.14)^0.5 = 5.7 in

Square Side =  (Area)^0.5 = 10.1 in