Big Project | Project | Project Manager |
|---|---|---|
Fixed wing | Landing gear |
Design and manufacture a landing gear for the post-comp fixed wing airframe.
Constraints | Written By | Append Date |
|---|---|---|
Supports a 5 kg frame
| July 28, 2024 | |
Plane does not tip about its center of gravity on ground. (need enough space between the front and rear wheels) | July 28, 2024 | |
Shock absorption mechanism (to prevent stress on the frame during landing) | July 28, 2024 | |
Minimum 2 inch prop clearance |
Subteam | Contact | Contact Description |
|---|---|---|
Assignee | Asana Task | Date |
|---|---|---|
July 31 2024 |
Include any updates here + reasoning
Tricycle vs tail dragger
leaning towards tail dragger, gives prop clearance and easier to mount to the frame
tail dragger risk of tipping?
landing will be more flat
tail dragger good
spring steel to absorb shock
about the same price as shock absorbers.
springs easier to maintain, specs are available
pneumatic shocks? probably stick with spring shocks
spring shock can’t be tuned easily
start off w aluminum
Implementing tail dragger design, two wheels at front one at tail
This will give prop more clearance as it is tilted back
Using aluminum sheet metal with bends to absorb energy
Aluminum was chosen as it is light weight and meets design specs with the lowest safety factor being about 30 when stationary
The design uses the bends to also help create a more stable place
Front landing gear bend out to give wider base of support
Back landing gear goes straight back to try and keep the centre as in line with the CoG as possible
Steerable tail wheel to be designed
by Oct 2 , 2024
Front landing gear looks good - make it taller by 2 inch ish
Revised Design
The front landing gear were updated so that they were one piece. This causes the internal moment to be transferred from one part of the landing gear to the other instead of the reaction coming from the frame itself.
The front landing gear was also made thicker so that it could mount in 4 places at once which allow it to be more secure and support more weight.
The front landing gear also has a safety factor of 3.15 when a total of 50 newtons are applied to the piece. The highest stress is at the outer points where the bolts connect to the frame of the plane.
The rear landing gear was changed so the wheel is in line with the mounting holes which will allow for better balance of the plane and also prevent the plane from turning to one side due to more friction on one side compared to the other.
Revised Design 2
This new design features a steerable landing gear. For this a new file was created so the original landing gear is still available in PDM. The design removes the tab from the stationary design that held the wheel and extends the bottom plate so that the wheel attachment can be easily mounted.
The new attachment goes over both sides of the wheel so that the wheel is equally supported. There is a single hole in both the support and attachment where a servo will go to allow the landing gear to be moved so that the plane is steerable.
Revised Design and Sims
The front landing gear had cutouts applied so that the weight of the part can be reduced.
The goal of the sim is to ensure that the cutout holes do not reduce the integrity of the part enough so that it would fail on landing.
Assuming that Eclipse is 5kg
Fg = 5(9.81)
= 49.05
Applying a safety factor of 3, 150 newtons was applied to the part
Used Aluminum Alloy
Load was applied to both axle holes
The mounting holes are the fixture for the test.
Trial # | Mesh Parameters | Screenshot |
|---|---|---|
1 | Element size: 2mm # of nodes: 38634 |
|
2 | Element size: 1mm # of nodes: 115345 |
 |
3 | Element size: # of nodes: |
|
Trial # | Maximum Stress (MPa) | Min Safety Factor | Screenshot |
|---|---|---|---|
1 | 138.17 | 1.72 |
|
2 | 154.83 | 1.3402 |
 
 
|
3 |
|
|
Could also include minimum safety factor.
The landing gear will be able to survive landing
Sims for Front Landing Gear with Triangle Holes
Assuming that Eclipse is 5kg
Fg = 5(9.81)
= 49.05
Applying a safety factor of 3, 150 newtons was applied to the part
Used Aluminum Alloy
Load was applied to both axle holes
The mounting holes are the fixture for the test.
Trial # | Mesh Parameters | Screenshot |
|---|---|---|
1 | Element size: 2mm # of nodes: 24269 |
|
2 | Element Size 1mm Nodes: 93681 |
|
Trial # | Maximum Stress (MPa) | Min Safety Factor | Screenshot |
|---|---|---|---|
1 | 111.83 | 2.50 |
|
2 | 144 | 1.9 |
 
|
The landing gear will be able to survive landing
Assuming that Eclipse is 5kg
Fg = 5(9.81)
= 49.05
Distance of rear landing gear to front landing gear = 676
Distance of front landing gear to CoM = 176
Moment = .176(49.05) - FN (.676)
0 = .176(49.05) - FN(.676)
FN(.676) = .176(49.05)
FN = 12.77N
Assuming coefficient of friction between concrete and foam is 1.8 (twice that of sliding friction, professor said that it would be higher than sliding friction)
radius = .037
Mass Moment of Inertia (xx direction) = 0.038527
alpha = angular velocity, assuming 1radian/sec
Torque = 1.8FN x r + I x alpha
= 0.889 Nm
Servo is 0.297Nm
So we need to select a new servo
Validate the rear landing gear.
Assuming that Eclipse is 5kg
Fg = 5(9.81)
= 49.05
Distance of rear landing gear to front landing gear = 676
Distance of front landing gear to CoM = 176
Moment = .176(49.05) - FN (.676)
0 = .176(49.05) - FN(.676)
FN(.676) = .176(49.05)
FN = 12.77N
Using Aluminum Alloy
Load was applied to the far servo holes
The mounting holes are the fixture for the test.
Trial | Mesh Parameters | Screen Shot |
|---|---|---|
1 | Element Size 1mm Nodes 29744 |
|
2 | Element Size .5mm Nodes 125884 |
|
Trial | Max Stress | Min Safety Factor | Screenshot |
|---|---|---|---|
1 | 97.386 | 2.5671 |
|
2 | 110.77MPa | 2.2569 |
|
