Universal Electric Airplane Tug

Inceptus wants an easy to use electric airplane tug that works with a wide variety of tire sizes as well as aircraft with wheel pants. 
=Problem Definition=
Background
Currently, there are no airplane tugs on the market that can tow multiple aircraft with little input from the user or without significant modification with changes in wheel type. As the average age of the general aviation pilot increases, the need for an easy to use powered airplane tug increases. Also, most flight schools have multiple airplane tugs to pull specific airplanes. The goal is to create a solution for this problem by designing an airplane tug that can be used with a wide variety of tire sizes and types including those with wheel pants. Our solution will be easy to use and require very little input from the user. 
==Specifications==
 Tire Sizes 
*The tug must be able to move aircraft with the following tire sizes:
**4.00x4
**5.00x6
**6.00x6
**7.00x6
**8.00x6
 Strength Requirements
*The design shall be able to carry a rolling load of 4000 lbs, up a 2% grade and must be able to handle a static load of 500 lbs.
Mounting/ Interface Requirements
*The tug shall be able to mount and interact with all different types of wheels, including wheels with pants.
=Project Learning=
==Pallet Jack==
The client wants a system that can be used as a prosthetic on the pallet jack shown below. The pallet jack is electric and can supply power to any electrical systems that might be used on the final design.
==Design Ideas==
===Design Idea 1===
Design Idea 1	Design Idea 1	Design Idea 1	Design Idea 1	Design Idea 1	Design Idea 1
Image 	Description 	 	 	 	
 	
*System without pallet jack
*Gate is closed by operator
*Linear actuator (not shown) pushes wheel against gate
*Sliding mechanism uses UHMW plastic to reduce friction and part count	 	 	 	
 	
*System on Pallet Jack	 	 	 	
 	
*The gate uses roller bearings to “lift” wheel when clamped
*V shape helps stabilize tires of different width	 	 	 	
===Design Idea 2===
Design Idea 2	Design Idea 2	Design Idea 2	Design Idea 2	Design Idea 2	Design Idea 2
Image 	Description 	 	 	 	
 	
*Pictured is the system without using the pallet jack
*This design is similar to the first except it uses roller bearings on the part that 
the linear actuator pushes on
*It uses square tubing in which the mechanism slides.	 	 	 	
 	
*System with a captured wheel	 	 	 	
 	
*This is the system on the pallet jack	 	 	 	
 	
*This is the part that the linear actuator will be pushing on	 	 	 	
===Design Idea 3===
Design Idea 3	Design Idea 3	Design Idea 3	Design Idea 3	Design Idea 3	Design Idea 3
Image 	Description 	 	 	 	
 	
*The series of pictures shows how the gate closes. 
*This design uses a two arm gate to capture the wheel, unlike the other two which 
use a single arm gate. 
*It uses a linkage system to close both arms at the same time.	 	 	 	
 	
*Stand alone system	 	 	 	
 	
*System on the pallet jack	 	 	 	
==Linear Actuator==
All of the ideas above use a linear actuator to capture an aircraft wheel. The linear actuator must have a stroke length of at least 10 inches. This could run off the power supply of the pallet jack. The pros of using a linear actuator are it is light weight, small in size, and has a long stroke length. The cons of using a linear actuator are they are expensive, needs power, and requires a control system.
==Using 8020==
The client suggested the use of 8020 to build the final design. Also, 8020 is modular and would allow rapid prototyping at a low cost, and there is large amount of scrap 8020 in the University of Idaho machine shop that can be used for free. 
=Final Design=
We combined the best parts of all three design ideas to make our final design. The design is meant to be a prosthetic attachment for an electric pallet jack that our client has given to us. The biggest problem we encountered was how to close and open the gate with little to no user input. The images below shows how the mechanism captures wheels, how the gate works, and how the clamp works. 
==Overall Design==
Overall Design	Overall Design	Overall Design	Overall Design	Overall Design	Overall Design
Image 	Description 	 	 	 	
 	
*The user will push the device up to the wheel they want to capture.	 	 	 	
 	
*They will push the device all the way up to the wheel.	 	 	 	
 	
*After the user pushes the device all the way up to the wheel, they will activate the
linear actuator which will start to close the gate behind the wheel.	 	 	 	
 	
*As the gate closes a latch will come down and lock the gate into position.	 	 	 	
 	
*When the gate is latched the wheel will be pushed up onto the gate and be lifted 
slightly so the user can move the aircraft around.	 	 	 	
==Gate Design==
Gate Design	Gate Design	Gate Design	Gate Design	Gate Design	Gate Design
Image 	Description	 	 	 	
 	
*On the right side a torsional spring keeps the gate open.
*On the left side a torsional spring keeps the latch in the open positon.	 	 	 	
 	
*The first paddle, on the right side, shuts the gate and keeps it closed.	 	 	 	
 	
*The second paddle, on the left side, pushes the latch to the closing position and 
keeps the gate closed.	 	 	 	
==Clamp Design==
Clamp Design	Clamp Design	Clamp Design	Clamp Design	Clamp Design	Clamp Design
Image 	Description 	 	 	 	
 	
*The clamp uses 1/2 inch steel rods with a UHMW tube over. It is similar to how 
a toilet paper roll works.
*This allows the wheel to roll on to the clamp which also pushes the wheel onto the gate.	 	 	 	
 	
*The clamp will be attached to the linear actuator.
*It will be mounted onto the 8020 frame by custom made sliders.	 	 	 	
==Manufacturing==
The majority of the parts were laser cut, and we used a slot and key design to simplify the manufacturing process. This design eliminates guess work and allows everything to be aligned properly. Also, we designed it so we only had to machine one part. 
To save money, we made custom linear sliders out of steel square tube. We purchased UHMW sliders and mounted them to the square tubing. We also made mounts for the latch and hinge out of steel square tube.
==Validation==
In testing we found that it picks up aircraft with tail wheels with ease.
We tested it with an aircraft with wheel pants and found that it works with no problems. Also, we found that the UHMW rollers work as predicted. When the wheel starts to get pinched the wheel starts to roll onto the rollers. One other thing we found out in testing was, if the aircraft as flat tire our product will not work very well, because it pinches the tire instead of lifting it. 
=Team Members=
	Name Josh Frei
Major: Mechanical Engineering
Hometown: Grangeville, ID 
Graduation Date: Spring 2019 
Future Plans: Josh will be going to work for a company in Grnageville.
Email: frei4286@vandals.uidaho.edu
	Name Nick Locke
Major: Mechanical Engineering
Hometown: Vancouver, WA 
Graduation Date: Spring 2019
Future Plans: Nick will be traveling around in a van.
Email: lock3401@vandals.uidaho.edu
	Name Max Johnson
Major: Mechanical Engineering
Hometown: Coeur d'Alene, ID
Graduation Date: Spring 2019
Future Plans: Max will be attending grad school in Fall 2019
Email:john9051@vandals.uidaho.edu
	Name Chase Anderson
Major: Mechanical Engineering
Hometown: Lewisville, TX
Graduation Date: Spring 2019 
Future Goals: Chase will be going to work for a company in the Seattle area.
Email: ande9000@vandals.uidaho.edu
=Additional Documentation=
Meeting Minutes
Presentations
Budget
Schedule