3. ● Design HAM Radio Tower with easy
access to antennas near ground level.
● $1500 cost
● 50 feet tall
● Transportable by normal methods
● Able to be assembled by only two men
● Must withstand 80 mph wind
● No maintenance for 20 years
Requirements
4.
5. ● Based on chosen motor
○ Motor needed to raise tower weight in allotted time
○ Chosen motor gives the transmitted load that the
gears need to be able lift
● analyzed multiple gear ratios
● decided on gear ratio of 6:1
○ pinion teeth = 16, Disk gear teeth = 96 teeth
● Go through analysis and find all constant
values
● Find gear bending stress/wear contact stress
● Use stresses to find Safety factors
Gear Analysis
6. Shaft Analysis
● Radial and Tangential
Forces
● Resultant Moments
● Alternating and Mean
Stresses
● Modified-Goodman for
infinite life
● 2x 0.75 l & 0.75 D (in)
● 1x 0.75 l & 4.0 (in)
● AISI 4140 Steel
Tempered & Quenched
7. Bearing Analysis
● Analysing/Summing forces of
each shaft resulting from gears
and cable etc.
● Choosing bearing style based on
loading forces present on shafts.
● Calculate critical dynamics load,
C10 value for each shaft.
● Shop for bearings based on
largest C10 value fitting desired
size dimensions.
● Confirm bearings spec’s for
failure by static load capacity C0
C10: 1,125lbs
C0: 657 lbs
8. Weld Analysis
1. Estimate Allowable Weld
Stress tau
2. Select an appropriate
Weld EXX Type
3. Find tau primary and tau
secondary
4. Total Weld Stress is the
Vector Sum of both types
of stresses
5. Find Safety using
Allowable Weld Stress
tau and Actual Weld
EXX 90
h = h/16
9. Wind Analysis
● Tower must withstand 80 mph wind with
temperatures found in the lower 48 States
● Reynolds Number in Transition Region of Air
● Bending Failure of Cylindrical Mast at 60
● Guidewires Can Resist hurricane wind
<220mph
12. Conclusion
● Telescope and Tilt provides the easiest access to
antennas
● Final budget was over maximum, but cost is justified by
high endurance and ease of use
● Fully extended tower reaches 50 feet tall
● Transportable by Semi, or can be further broken down
for transportation by 9 foot trailer.
● Able to be assembled by only two men
● Withstands 60 mph without guy-wires and higher winds
with optional wires to improve withstands of 220 mph
● No maintenance for 20 years
13. Opportunities for Improvement
● The mast was most likely over designed and
could be made smaller and lighter with a
different material using permanent guy-wires
if guy-wires were not a problem.
● The price of the motor could be reduced with
a more complicated gear box, however this
would also introduce more locations of
failure.
