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Engineering project, leaving cert 2012

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    #92
    Novenine
    Closed Accounts Posts: 4 ✭Novenine


    Hey guys, Having lots of trouble! I wanted to do the easy rack in pinion kind of thing but my teacher is mad.. one person in the class already has that idea and he won't let any of us use a rack pinion mechanism now. So I am researching my balls off now and had to scrap my design.
    I'm looking at a Crossed Dual Drag Link, but can't figure out how it actually functions.. also I'm troubled as to how I'm going to attach motors to the wheels when the hub will already be full with the steering mechanism! http://www.ihpva.org/Projects/PracticalInnovations/weld.html the CDDL is on this page


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    #93
    partyatmygaff
    Registered Users Posts: 10,992 ✭✭✭✭partyatmygaff


    Novenine wrote: »
    Hey guys, Having lots of trouble! I wanted to do the easy rack in pinion kind of thing but my teacher is mad.. one person in the class already has that idea and he won't let any of us use a rack pinion mechanism now. So I am researching my balls off now and had to scrap my design.
    That's ridiculous. That's as daft as saying "Ah, they're using round wheels in their project. You can't use round wheels as well or it will look like you copied their idea.". Rack and Pinions are almost a standard when it comes to model steering mechanisms. Expecting twenty or so people to come up with completely different steering mechanisms is crazy.


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    #94
    Novenine
    Closed Accounts Posts: 4 ✭Novenine


    partyatmygaff wrote: »
    That's ridiculous. That's as daft as saying "Ah, they're using round wheels in their project. You can't use round wheels as well or it will look like you copied their idea.". Rack and Pinions are almost a standard when it comes to model steering mechanisms. Expecting twenty or so people to come up with completely different steering mechanisms is crazy.


    I know, but he won't let me do it, he said something about not verifying its my work if I go ahead with it. I had an entire design completed and I had to scrap it! :(


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    #95
    partyatmygaff
    Registered Users Posts: 10,992 ✭✭✭✭partyatmygaff


    Novenine wrote: »
    I know, but he won't let me do it, he said something about not verifying its my work if I go ahead with it. I had an entire design completed and I had to scrap it! :(
    Complain to your Principal and have your principal deal with him. That's ridiculous. Putting you under extra stress, delaying your project and potentially costing you a grade or two just because of his own daft opinions is not on.

    Although, that said, if you could design something that worked more elegantly than a rack and pinion then that could very well improve your mark.


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    #96
    Novenine
    Closed Accounts Posts: 4 ✭Novenine


    partyatmygaff wrote: »
    Complain to your Principal and have your principal deal with him. That's ridiculous. Putting you under extra stress, delaying your project and potentially costing you a grade or two just because of his own daft opinions is not on.

    Although, that said, if you could design something that worked more elegantly than a rack and pinion then that could very well improve your mark.

    Cheers for the concern man, but our principal wouldn't dare cross him, Complaining will just get us thrown out of the classroom, meaning no grade :L
    F'd up system in our school. I only started engineering in 5th year..
    So basically I'm trying to design an entirely unique steering mechanism, I have a few little cardboard model mechanisms made here, just having a problem attaching a motor to each front wheel..
    I have a bar going into the centre of the wheel already, how can I get a motor to turn the wheel then?

    Oh also, our teacher has complained about suspension on these LRVs, he says its impractical and unnecessary for the moon.


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    #97
    partyatmygaff
    Registered Users Posts: 10,992 ✭✭✭✭partyatmygaff


    Novenine wrote: »
    Cheers for the concern man, but our principal wouldn't dare cross him, Complaining will just get us thrown out of the classroom, meaning no grade :L
    F'd up system in our school. I only started engineering in 5th year..
    So basically I'm trying to design an entirely unique steering mechanism, I have a few little cardboard model mechanisms made here, just having a problem attaching a motor to each front wheel..
    I have a bar going into the centre of the wheel already, how can I get a motor to turn the wheel then?

    Oh also, our teacher has complained about suspension on these LRVs, he says its impractical and unnecessary for the moon.
    http://dayton.hq.nasa.gov/IMAGES/MEDIUM/GPN-2000-001289.jpg
    http://www.kasmamagazine.com/images/relativebabble/surface-of-moon.jpg

    Let me get this straight... your Engineering teacher told you that suspension is impractical and unnecessary on the moon?

    Erm...


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    #98
    Novenine
    Closed Accounts Posts: 4 ✭Novenine


    partyatmygaff wrote: »
    http://dayton.hq.nasa.gov/IMAGES/MEDIUM/GPN-2000-001289.jpg
    http://www.kasmamagazine.com/images/relativebabble/surface-of-moon.jpg

    Let me get this straight... your Engineering teacher told you that suspension is impractical and unnecessary on the moon?

    Erm...

    :L Exactly! I said about all the terrain and he started talking to me as if I was stupid- He like put words in my mouth making it sound like I thought the gravity was just like on earth. Gah, Boards.ie is my new engineering teacher :D


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    #99
    Fiendish Human
    Closed Accounts Posts: 29 ✭Fiendish Human


    Novenine wrote: »
    Cheers for the concern man, but our principal wouldn't dare cross him, Complaining will just get us thrown out of the classroom, meaning no grade :L
    F'd up system in our school. I only started engineering in 5th year..
    So basically I'm trying to design an entirely unique steering mechanism, I have a few little cardboard model mechanisms made here, just having a problem attaching a motor to each front wheel..
    I have a bar going into the centre of the wheel already, how can I get a motor to turn the wheel then?

    Oh also, our teacher has complained about suspension on these LRVs, he says its impractical and unnecessary for the moon.

    No offence to your engineering teacher but that is quite possibly the most ridiculous statement of the century. Suspension not necessary on the moon?....Wow is all I can say. As for the rack and pinion idea... Coming up with an entirely original steering system would have to be the work of genius, it's a leaving certificate project... not NASA. I second what partyatmygaff said: reserving such a broad idea to one student is preposterous! I hope for your sake that your taking the piss here, if not then talk to some of your school's other tech teachers.


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    #100
    ghilliemaster
    Registered Users Posts: 37 ✭ghilliemaster


    Hi lads
    what i was thinking of doing was a simple,yet good looking roll cage type shell.looks great a guy in my class did it for the junior and it looked very impresive.joined it together with solder and it was sturdy.Any ideas on that?.Also ye think we would have to put a satelite type deal on it?? it being a lrv and all!
    any one started on the second part of the folio.Having a spot of trouble with it :D


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    #101
    Fiendish Human
    Closed Accounts Posts: 29 ✭Fiendish Human


    ghilliemaster wrote: »
    Hi lads
    what i was thinking of doing was a simple,yet good looking roll cage type shell.looks great a guy in my class did it for the junior and it looked very impresive.joined it together with solder and it was sturdy.Any ideas on that?.Also ye think we would have to put a satelite type deal on it?? it being a lrv and all!
    any one started on the second part of the folio.Having a spot of trouble with it :D

    Cool idea! Over-crossing bars would be quite sturdy and light indeed! :D
    As for the satellite: Not entirely necessary. Yes, LRVs in reality would have some satellites, but seeing as your making a model of an LRV, a satellite would really just be for decoration. My advice: build the thing, and if you have any time left over then add your satellite, astronaut manikin, logos etc. Focus on the tasks in the brief first (i.e. the steering, the individual motor drives etc.) then tackle the extras. :)


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    #102
    Bbbbolger
    Registered Users Posts: 448 ✭✭Bbbbolger


    Probably a stupid question but when the brief states weight is a key issue does that mean they intentionally made it light or heavy? I can see arguments for both so if anyone could shed some light on it for me?


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    #103
    fullback4glin
    Closed Accounts Posts: 383 ✭✭fullback4glin


    I'd assume light because it has to be transported to the moon so I can't imagine they'd want it to be too heavy.


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    #104
    Bbbbolger
    Registered Users Posts: 448 ✭✭Bbbbolger


    Good point. I had got it stuck on my head that it would have to be heavier due to the lower gravity of the moon.


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    #105
    Fiendish Human
    Closed Accounts Posts: 29 ✭Fiendish Human


    Bbbbolger wrote: »
    Good point. I had got it stuck on my head that it would have to be heavier due to the lower gravity of the moon.

    Think of the gravity on the Moon as a great asset. It would be a shame to "anchor" the LRV slightly so that it would still be subject to the limitations of Earth gravity. I'd personally find it quite fun sitting on an LRV, jumping around the surface of the Moon :D


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    #106
    confuzeled!!!!
    Closed Accounts Posts: 2 ✭confuzeled!!!!


    Hi, Can anyone help me with any ideas for my project kinda behind and dont know what to use as in the steering and all, any suggestions would be great.:D


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    #107
    youngcardinal
    Closed Accounts Posts: 24 ✭youngcardinal


    hello :) just wondering has anyone thought about what materials they're gonna use?


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    #108
    confuzeled!!!!
    Closed Accounts Posts: 2 ✭confuzeled!!!!


    hi, can anyone give me any ideas for this project im kinda behind and have no idea atm...


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    #109
    Fiendish Human
    Closed Accounts Posts: 29 ✭Fiendish Human


    confuzeled!!!! wrote: »
    hi, can anyone give me any ideas for this project im kinda behind and have no idea atm...

    Maybe this would be a good place to start...


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    #110
    Darius.Tr
    Registered Users Posts: 613 ✭✭✭Darius.Tr


    Seems like a great project this year, alot better than last years... Good luck to everyone who is doing it this year :)


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    #111
    ghilliemaster
    Registered Users Posts: 37 ✭ghilliemaster


    any of ye doing the steering meck on yer models??


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    #112
    Iony94
    Registered Users Posts: 60 ✭✭Iony94


    How would yous incorporate the suspensions on the LRV ? :confused::confused:


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    #113
    Leftyflip
    Registered Users Posts: 7,463 ✭✭✭Leftyflip


    Suspension - with a lot of thought and ingenuity, honestly - it's a complicated thing to do with the size constraints.

    Steering mech - the possibilities are endless, rack and pinion, linkages, etc, etc.

    How far along is everyone at the moment anyway?


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    #114
    Iony94
    Registered Users Posts: 60 ✭✭Iony94


    Chassis and Steering mechanism done :) . Any ideas for the wheels ?


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    #115
    Fiendish Human
    Closed Accounts Posts: 29 ✭Fiendish Human


    Iony94 wrote: »
    Chassis and Steering mechanism done :) . Any ideas for the wheels ?

    You could build the wheels yourself using sheet metal or some other light material or you could use the pre-made ones in your classroom. I was going to build them myself but then realising how time consuming it would be decided to just use the already made ones.


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    #116
    Mayo_Boy
    Registered Users Posts: 661 ✭✭✭Mayo_Boy


    Fiendish Human wrote: »
    You could build the wheels yourself using sheet metal or some other light material or you could use the pre-made ones in your classroom. I was going to build them myself but then realising how time consuming it would be decided to just use the already made ones.

    would you not be better using nylon for the wheels and make them on the lathe?


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    #117
    Iony94
    Registered Users Posts: 60 ✭✭Iony94


    Mayo_Boy wrote: »
    would you not be better using nylon for the wheels and make them on the lathe?

    I think you would yes :) . That's what I will probably do . Also you could drill 4 or 5 holes into the wheel for the design


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    #118
    Wilwarin
    Registered Users Posts: 33 ✭Wilwarin


    If the LRV has to have individual drives for front wheels, why does it have to have steering mechanism for the front wheels? You can steer with the individual drives, as it has no sense on turning the front axle plus the individual drive. or should it be one variable resistor for both engines?


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    #119
    partyatmygaff
    Registered Users Posts: 10,992 ✭✭✭✭partyatmygaff


    You're thinking of tanks. Trying to steer a four wheeled vehicle by just controlling the rotational speeds of the two front wheels is impossible.


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    #120
    Fiendish Human
    Closed Accounts Posts: 29 ✭Fiendish Human


    partyatmygaff wrote: »
    You're thinking of tanks. Trying to steer a four wheeled vehicle by just controlling the rotational speeds of the two front wheels is impossible.

    I wouldn't go as far as to say it's impossible, just not very effective :rolleyes: As for Wilwaren's question: We have to do both the steering and the individual drives because it would improve control over the LRV for the astronauts AND because the brief said so.


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    #121
    Wilwarin
    Registered Users Posts: 33 ✭Wilwarin


    and what if the front axle would be on a bearing and the individual drives would turn it by accelerating one wheel?


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