Fixed wing landing gear

Task Description

Design and manufacture a landing gear for the post-comp fixed wing airframe.

Constraints

Relevant Contacts

Assignees

Task Progression/Updates

Author: @ person updating Date: YYYY/MM/DD

UPDATE TITLE

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

Author: Ben Lovegrove 2024/09/05

Initial Design

• 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

Author: Smile Khatri 2024/09/23

• Steerable tail wheel to be designed

  • by Oct 2 , 2024

• Front landing gear looks good - make it taller by 2 inch ish

Author: Ben Lovegrove 2024/09/26

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.

Author: Ben Lovegrove 2024/10/03

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.

Author: Ben Lovegrove 2024/10/10

Revised Design and Sims

The front landing gear had cutouts applied so that the weight of the part can be reduced.

Objective of Sim

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.

Simulation Setup

Assumptions and Preliminary Calculations

• 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

Applied Loads

Load was applied to both axle holes

Fixtures

The mounting holes are the fixture for the test.

Mesh

Trial #	Mesh Parameters	Screenshot
1	Element size: 2mm # of nodes: 38634
2	Element size: 1mm # of nodes: 115345
3	Element size: # of nodes:

Results

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.

Conclusion

• The landing gear will be able to survive landing

Author: Ben Lovegrove 10/11/2024

Sims for Front Landing Gear with Triangle Holes

Simulation Setup

Assumptions and Preliminary Calculations

• 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

Applied Loads

Load was applied to both axle holes

Fixtures

The mounting holes are the fixture for the test.

Mesh

Trial #	Mesh Parameters	Screenshot
1	Element size: 2mm # of nodes: 24269
2	Element Size 1mm Nodes: 93681

Results

Trial #	Maximum Stress (MPa)	Min Safety Factor	Screenshot
1	111.83	2.50
2	144	1.9

Conclusion

• The landing gear will be able to survive landing

Author: Ben Lovegrove Date: 10/11/2024

Validation of Servo

• 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

Author Ben Lovegrove

Rear Landing Gear

Objective of Simulation

Validate the rear landing gear.

Assumptions and Preliminary Calculations

• 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

Applied Loads

Load was applied to the far servo holes

Fixtures

The mounting holes are the fixture for the test.

Mesh

Results

Author: Smile Khatri 2024/11/13

Awesome work so far, super happy to see the engineering work you’ve put into the landing gear! Some next steps:

• Where are we getting the servo attachment disk from? Do you have a specific part #?

• Can you look into which servo we should order?

• Other than that, the rest looks good. Best way to find out if it works is by making it and testing it!