Engineering Project Help Please!! Need Creative Minds!!

I don't know if the OP is still monitoring, but I think the idea of having our own group of 'student projects' is very interesting, as these get a lot of participation, and when they take a left turn, as in Del the Cat's rubber band discussion, the are also quite fun.

Its amazing to see how this scenario tends to engage people's creativity, when the realities of reality are lifted.

chris

hey yea guys, im still monitoring, sorry about not responding in a little while, life of an engineering student isnt too easy lol. But to answer your question, i can burn something up (as long as its not combustable). And what they meant by not leaving anything on the track has to do with just like dropping a weight or a peice of your car on the ground.

"i can burn something up (as long as its not combustable)."

Oh, come on, now!

Can you post or give us a link to the Rules, so we're not stumbling around (under a Mushroom Management scenario) with goalposts moving nearly as quickly as in the "real world"? This is a fun-type project, yes?

A link to your dictionary containing the definitions of "burn" and "combustable" may also provide enlightenment.

He should go int politics

Sounds like you need a just a delivery device, not a receiving..........how about a Trebuchet http://en.wikipedia.org/wiki/Trebuchet

sorry, I see that was in an earlier posts, how about a sling shot (water ballon launcher)

not done reading all the posts and my edit time is almost up

phoenix911

Ok, well here are all of the rules to the competition that the professor just uploaded and it seems that there has been one big change to the vehicle, it can now only be 2'2'3'. But other than that, its pretty much the same, just in much more detail. And in case your wondering, the "theme" of the project is like a transporter on mars, so that's why everything might be stated a little oddly.

Competition Rules

As you will be competing for the best design, the following rules and guidelines have been

set forth to ensure that all participating teams will be judged by the same criteria:

1. The final device that will be placed on the mission will have the dimensions of a large

vehicle; therefore, for initial testing it was decided to develop scale models at 1:6 scale.

Thus, applying this scale to the final dimensions allowed on the mission, your allowable

dimensions for your device are 2' x 2' by 3' high. To verify that your device fits within

these constraints, a box will be placed over your device at the starting line; if it does not

fit completely within the specified constraints, your team will be disqualified and will

receive the default score for the competition (refer to scoring section). No manual

expansion or assembly will be allowed once your device has been measured.

2. The total cost of the device must not exceed $80.00. Receipts must be attached to your

final report and be available at the check‐in station the day of the competition. If you

cannot provide receipts, or the cost expressed on the receipts are not fair‐market value

(no eBay purchases from your friends), your team will be disqualified. All parts used

must be counted towards the allotted budget, and any donated parts must have an

equivalent fair‐market price associated with it; you must provide proof of your recorded

price (store ad, online price search, etc.) with your final report. Pro‐rating items based

on consumption is acceptable; for example, if you buy a box of 100 nails for $4.00 and

you only use 10 nails, you only need to record $0.40 as the actual cost of nails. However,

keep in mind that you must provide receipts documenting the total cost and the prorated

quantity.

3. The maximum distance that your vehicle will be able to travel is 250 feet. Anything

beyond 250 feet will be recorded as the maximum value (so if you travel 300 feet, you

will only receive credit for 250 feet).

4. Although up to two (2) human loaders from your team will be able to be at the starting

line to assist in setup and weight loading, they are not allowed to impart ANY initial

velocity to the vehicle, nor are any members of your team allowed to cross the starting

line for any reason. This eliminates any designs that rely on the human loader to push

the vehicle down the course. This rule does not prevent the human loader from holding

the vehicle (preventing it from traveling) then letting go once the heat begins, so long as

the loader simply lets go, imparting no initial velocity.

5. As the current competition is simply a proof of concept design, the weight that will be

loaded on your vehicle will be that of liquid water. No containers of any kind will be

provided at the competition; therefore, your device must be capable of self‐containing

the entire load in water. Water will be provided either by trough (you will be able to

scoop out the water and fill your device), or if your device will be carrying large amounts

of water, a hose will be provided as well.

6. All components of your operating device will be considered in the size, weight, and cost

constraints, as well as the unloaded weight measurement for your transporter. This

includes any containers used to hold the water.

7. All devices must be self guided; absolutely no remote control and no string or line‐based

guidance systems will be allowed.

8. As stated in the objectives, absolutely no electronic devices may be used on your

transporter. Please note that the reason for disallowing electronic devices is potential

failure due to EMI, and as such, it is the act of using electricity which is explicitly

disallowed. Thus, if you include an electronic device, but do not use any electricity (for

example, you use a motor, but do not provide electricity to power it) this is acceptable.

9. You must bring your device to the competition unloaded and fill it with the desired

amount of water on site. You will not be allowed to use your own weights or pre‐fill

your device prior to the competition.

10. Your transport vehicle has a maximum allowable unloaded weight of 50 lbs (i.e. your

vehicle can weight up to 50 lbs before you load the water). Exceeding these limits will

result in disqualification.

11. There is no maximum amount of water that you may carry, however, keep in mind that

your device must remain within the size constraints after the water has been loaded

onto your vehicle.

12. Your groups must consist of 3 to 5 students and you must all be in the same lab section

in order to participate as a team.

13. Your team must perform all production of the device themselves (no commercial

manufacturing). No preassembled parts or kits will be allowed.

14. No liquid flammable objects are allowed (including gasoline and other liquid

combustible fuels), nor are any solid rocket fuels going to be permitted due to

transportation concerns en route to Mars.

15. No animals of any kind are allowed in your design.

16. All designs must be capable of finishing, at most, 2 trials.

17. If each run uses disposable items (i.e. CO2 cartridges, etc), then the total cost of your

device must be calculated on the total items used in BOTH trials.

18. A list of ALL materials used must be submitted on competition day with receipts.

19. Ties will be decided first by cost, second by running time.

20. After the trial runs, the top 16 teams will be invited to come back and compete in the

finals. During the finals the invited teams will be allowed to carry a different amount of

water (if desired) and the final winner will be decided solely based on performance

during the finals. However, the performance score for the teams that compete in the

finals will be the larger of their two scores.

21. The competition will take place on a relatively smooth, flat, paved surface. However, in

order to simulate Mars surface, there may be slight variations in the surface as well as

potential unevenness of the terrain. The event will not take place on grass, gravel, or

dirt.

file:///C:/Users/Matt%20Sexton/Documents/Competition%20Rules.doc

That really clears things up. I've been following this thread, and not posted until this point. I think Aussiebob, post #18, and Del_the_Cat, post #11 are your best bet. Simple, cheap, and it will work. (If I missed anyone else with this suggestion, sorry).

Read those rules over 25 times. Then read them over 25 more times. Just make sure your in complete compliance, and exploit any loopholes!

OK. Things are different from your initial post. Your link after the rules did not work. I didn't see in the rules the amount of water required to be transported. I would use a torsion spring design. An inner tube rubber is an excellent choice. A tire store would give you an old damaged one with street value of $0.01. And I would use as large of diameter wheels as possible - even 24" bicycle wheels. Any small imperfection in the terrain would then be negligible. I would get a thin plastic bucket if it would contain the volume of water required. If not, I would build a container out of balsa wood with wire reinforced "hoops" wrapped around it and double line it with a trash bag to contain your water. Figure ways to secure mounting points for the axel and drive system. I would look for a way to run it through the container perhaps having the torsion device in the water if needed. I would keep this vehicle as light as possible because your points drop in direct proportion to the Weight of the unloaded vehicle. If using a bicycle wheel, take out as many spokes as possible. Get rid of the tires. Use plastic nuts instead of metal. Drill large holes in the rim after the spokes are removed. You get the idea. Now for the loopholes. The obvious one is the weight of the vehicle and the fact that you can't add anything to your vehicle or expand it in any way. But you can take something off of it. If your vehicle is light enough, you could lighten it even further by creating a 2'x2'x3' "balloon" with your device encapsulated. Fill it with Helium. If your vehicle is light enough, the extra lift provided by the helium approximately 2 lbs may be worth the point increase. Simply remove the "cover" (which could be a trash bag(s)) releasing the helium after the weigh in.

It's too bad you have the 80.00 spending cap. Because with a small hydraulic/pneumatic motor, Properly sized accumulator, and appropriate valves, this would be easy.

Unfortunately you would have a hard time staying within budget. I would have to say a "wind-up" motor of some kind is the most feseable for your guidelines. You should be able to design a motor using some kind of energy storing material in tension/torque/compression, such as a steel spring, rubberband, ect. I would have to say the simplest/cheapest/lightest would have to be an elastomer of some kind, such as a large rubberband-like material wound around a shaft as stated above in the thread.

I try to design in line with these words:

Everything should be made as simple as possible, but not simpler.

-Albert Einstein

Having had a look at the rules, I still think my original idea of using the water as a potential energy source and gravity as the motive force is still a "goer". I would construct the thing from plywood (to keep the costs and the weight down) and use a nylon strap as the power transmission device. By using a system of pulleys (that could be cut from the plywood and turned round) I would then run the strap directly around the axle (not attached so that it free wheels at the end). You could have a wooden disc on either side to keep it straight - the strap wound around would have a much bigger diameter when fully retracted so the mechanical torque available at the start would be considerably increased (automatically reducing as speed and forward motion increases). For wheels I would consider three on each side (made from plywood with 1/2" wide self adhesive rubber "door seal" foam attached to the circumference for tyres. This would help handle the variations in the paved surface. The 'inner box' that contains the water could be 8" deep x 1'9" x 1'9" say and could hold 125lbs of water with a total travel of about 2'. With a bit of work with levers and pulleys I am sure you would get plenty of motive force to move your device 250'.

Regards,

Pete.

You of course would be taking into account all the frictions of all the pullys, transfering your power through a series of devices can become overcomplicated quickly. The idea is creative, gravity is a great source of constant potential energy, no doubt about that. I just worry that the limited amount of travel available for the mass to decend might not be enough to give a resonable ammount of force, even with an elabotare pully system. I'm not saying that it wont work by any means, just that it may more complicated than neccessary.

But going in the other end of the spectrum... If your already overcomlicating things, why not make an elaborate hybrid of multiple systems. Take the stored wind up motor for some inital force to get it going... dont attach the end of the elastomer strap as you would expect, instead attach it so when it comes to the end of its usefull stage, have it pull the pin to start the gravity device on its voyage... when you reach the end of the gravity device, have it trigger a device to tap your Co2 cartridges for your final boost to the finish line.

Now for the eye candy: While this is all taking place, have a elaborate marble run, traversing through the contraption so as to fool the onlookers that the marble is causing some magical things to happen as it pings through its maze of perfectly bent wires/tubes and such.

....Ahhh... the sound of success.

Couldent help but take a semi-comical approach.

New and different idea.

Have two tanks,

Make your first "tank" have multiple cells each insulated from the next (firbeglass, mulitple compartments) and build a "dry" battery that is activated by the addition of the water. (Might need a little salt in each compartment to help the reaction along.)

Galvanic series will tell you what metals to use for your electrodes, and build a multiple cell battery. (Electrode surface area will determine maximum current available.)

Use this battery to run an electric motor.

Make the second tank as large as feasible to fit the remaining space. (Maybe even use water bladders and have a mesh cage to contain them to save the weight (and cost) of a large tank.)

See "Dell's junkyard battery" thread for ideas on home made batteries.

One additive that works would be acetic acid, so you could deliver water and as an added bonus some "tangy" citrus flavoured drink as well.

8. As stated in the objectives, absolutely no electronic devices may be used on your

transporter. Please note that the reason for disallowing electronic devices is potential

failure due to EMI, and as such, it is the act of using electricity which is explicitly

disallowed. Thus, if you include an electronic device, but do not use any electricity (for

example, you use a motor, but do not provide electricity to power it) this is acceptable.

And all for under $80!

Notwithstanding the comment by BruceFlorida way back when this thing started (and I must say I do agree with his comments - students do need to learn how to unleash their own curiosity and creativity themselves) it has been really interesting following this thread, and I have to say that it gives me a great sense of confidence in our world that truly creative and inquisitive minds are still being exercised freely.

Naturally as mechanically minded people, we are obviously open to this sort of challenge, so I say, BRING IT ON! It gets the neurons moving and there can't be anything wrong with that.

Cheers,

Pete.

The question I just have to ask the Original Poster is this:

Are you going to use this question as a puzzle for your students?

The reason I ask, is that the goal posts were moved from the original position.

Kind Regards....

just replying to your post, i am the student trying to figure out solution, not the teacher.

but after reading the replies, i am strongly contemplating using a mixture of ideas to trigger at different parts of the run, as previously stated by RVZ717's post

As I said before: keep it simple. Using a mixture of ideas only introduces more things that can go wrong.

Now that I have been able to look at the original equation clearly: it reduces to this (if you don't use any of the water on the trip)

(Weight of Water)^1.6 * (0.4*distance)^1.2 / (Weight of Cart)

Assuming that the weights are in pounds and the distance is in feet then you get 157 points for moving 40 lb of water in a 20 lb cart 15 feet.

You're not trying to get more than 150 points, and dead heats are decided first on cost and second on speed to complete the challenge.

It's clear that increasing the weight of the water (relative to the weight of cart) is the most advantageous thing to do.

Holding up a plastic container full of water with very strong fishing line which is taken over a couple of pulleys and then wrapped around the axle, or, wrapping a bicycle inner tube around the axle will easily take you the 15 feet. So now you just need to cost up the options and work out which is cheapest.

Put that equation into a spread sheet and play around with the three variables (weight of water, weight of cart and distance travelled) to get a feel for what you're really trying to achieve.

Even if your prof. changes the goal posts again and removes the 150 point limit, you won't go far wrong with this approach.

I'm more stuck now since the publishing of the rules.. they are somewhat forbidding to accomplish with such a limited budget. In application of the term, 'fair market value, I wonder if the professor means to prevent used goods, but surely a junkyard is something everyone has access to. but for the moment, I will assume that it is out.

I took a stroll through my local peavey mart (http://www.peaveymart.com/) here in canada.. and found a number of useful items.. but still the 80$/50lb limit is a problem. I found a 5 gallon steel air tank.. 49.95$. I found clear plastic square garbage can.. 12" x 12" x 30" high for 15$. I found bungee cords 3.95 ea. ,and rubber load tie-down straps (very similar to bungee cord) 1.95 ea.. fairly powerful elastically. I also found the afformentioned inner tube (lawn tractor) for 7.95$. found small casters 4.95 a pair. (now that I think of it, some of those plastic refrigerator wheel systems would possible be of use). I also found a fairly strong axial coil spring for 15$. (used on plow) but getting it all together is more of a challenge. I believe some lightweight plywood or corrugated plastic sheet would be a useful construction material. there is also small toy tractors.. but we are not allowed to use existing assemblies.. so that is out.

What I did not see prevented in the spec was.. making your own parts from raw materials.. for example.. if you had your own forge/crucible/sandbox. and a lathe and a mill.. you could make all the gears, and transmission systems you wanted.. the actual metal is afforable I think.. depending on the metal (aluminum gears?) or plastics you choose. fiberglass is very light and tough.. advanced composite materials.. if you have the technology.. it is only the final cost of materials that is limited to 80$.. not the production tools and technology... If you had access to a 3D printer.. even those gears/bearings/parts might be strong enough to last 2 trips, and lightweight.

maybe for the fluid container.. you could use a cardboard box.. put a plastic garbage bag in it as a liner.. then reinforce the outside with industrial plastic stretch-wrap if needed, or a few rounds of packing tape.

the crux of the problem is how to transmit linear power from springs to many rotations.. when you can't afford retail gears and bearings. wheels and axles you can make out of wood. but the bearings will likely be journal bearings made from HDPE plastic.. maybe have to buy a plastic jug of milk to get some.. gears...

nope.. will have to think some more.

o, and there is one thing i forgot to mention, alot of people are figuring out the easiest way to get 150 points, but as we all know, a well build transporter will get well over that margin. So, for extra motivation, if i get first place they offered a scholarship for all four years that will pay for my books, so that is why i am trying to possibly expand my ideas and not keep it too simple.

o and for chrisg288, you can use as many old materials just lieing around as you like, but the proffessor has to agree on a fair market value, which means that sadly, ebay prices are out of the question... ha

Hello Guest,

Of course the Professor is not stupid, nor are most of the students in his class.

Because Forum is a public access one, I'm sure there will be many viewers here, the Professor and classmates also.

Kind Regards....

"And for the other question yea im a student at University of Central Florida"

Is that where everybody has to go for you to shout a round, or is it just a cover story ? It's not fair to give CR4 Admin a head-start with your IP address, there wont be any beer left for the rest of us.