Great Orange Navel Race

[Downtownbrown26]

I have to design a miniature boat to travel around my schools fountain. It can not cost more that 60 dollars and can not use remote controls. It also can not run on flammable liquids such as gasoline. It has to complete the journey under five minutes while carrying an orange on it. If you have any suggestions it would be greatly appreciated since I have no clue where to start

[marshmat]

Sounds like fun.

Sail or power? Any rules (like number of hulls, size, allowed to ask for help online)? An orange weighs what, 200-400 grams... hmm....

[Kay9]

I would buy one of those cheap electric toy boats then rig the rudder to make a turn at a preset iterval with somekind of clock. Ill put some more thought into this but it should be kind of easy to make. Might not win, but it will make a good show.

Or, you could take a small pice of wood, and make a rubberband engine for it. Let me find a link.
here ya go: http://noether.physics.ubc.ca/Olympics/Olympics94/Rubboat.html
http://www.docfizzix.com/shop/vehicle-kits/rubber-band.shtml

[Downtownbrown26]

There are no rules concerning size, hulls and such the only really other rule i forgot to say is that we are not allowed to buy anything that has been previously manufactured and and can not use any type of remote control. We were also told that the orange will be any where from a quarter pound in weight to a half pound so that makes its more difficult. And the fastest boat with the best design wins a scholarship for the rest of the books while I am in college at UCF so I want to try and at least have a chance to win

[Downtownbrown26]

Everything must be built by hand

[PAR]

That's an interesting set of engineering and yacht design issues. Which fountain? General shape and tacking room?

Clearly you'll have to have a self controlled boat, likely sail if you can't use anything manufactured.

If you sailed with some rudder deflection, you could possibly go to one side, scrape your way along the perimeter of the fountain, until she fell off on the other tack and hopefully sail back to the starting point, again dragging it's hull along the inside of the fountain this time.

A rubber band powered prop is an option, but you'd have a limited amount of return (duration), though this could be controlled to some degree.

I suspect the likelihood of circumnavigating the fountain is remote, but solutions to the various engineering issues are the goals of the problem. This means they'll be looking for clever and elegant problem solving, rather then actual success.

Which course are you involved in? I'm about an hour north of Orlando.

[messabout]

This is an excercise in creative thinking. You have said that you are not allowed to use "anything previously manufactured". How shall we take that meaning? Does it mean that you can not use a previously built or manufactured boat, or does it mean that you can not use ANYTHING previously manufactured such as a piece of copper wire or some AA batteries? On the one hand it means that you must construct the boat as if you were in the deepest jungles of the Amazon. Or you may construct the boat of available materials from the hardware store or elsewhere. The rule says that you can not spend more than $60, so I presume that you can in fact buy some matrial in addition to the wood that you'd probably use. (wood is not counted as manufactured, I suspect)

Pars' idea of having the boat scrape around the fountain perimeter has possibilities. I'm thinking of a rudder with a system of levers (tiller) and wheels or rollers that can steer the boat somewhat, but continue to allow the boat to stay in contact with the fountain perimeter. Propulsion: Let us imagine that a little Mabuchi motor is allowed. You can get one of those at the hobby shop, from a cordless drill, even from an electric toothbrush or one of those thingys that spray soap scum solution inside the shower stall (SC Johnson device I think). The sprayer device has a lot of very useable gears inside it. It also has a timer circuit that delays start for 15 seconds and then shuts the motor off after a few more seconds. Are we getting the idea yet? The tiller arrangement can actuate the start button found on the sprayer gadget, as well as providing some steering input for the rudder. If the motor, gears, and circuit board are disqualified then you'll have to become more creative. The boat should have a skeg or some other way to make it tend to go in a straight line, deviating from straight only when there is rudder input. Hopefully that will keep the boat at or near the perimeter wall.

If the parts from the sprayer or drill is deemed illegal then you will need to make your own motor. That is not as difficult as one might imagine. A few turns of wire , a pair of magnets, and a commutator. The com is made from a piece of split copper tubing glued to a small length of dowel rod. Brushes can be made from a piece of brass shimstock. You will need to gear the motors rotation down to drive a propeller. The prop ought to be large diameter and low pitch. Not hard to make. Presuming that gearing is not allowed then you'll belt drive the reductions with rubber bands and wood dowels of suitable relative diameters. Are we having fun yet?

If the sprayer thing is possibly legal then I will give you the innards of the one that I recently opened to see what made it tick. PM me if you need to have these parts for free. This can be a worthy project for you because the book subsidy can be quite valuable. Not only that, but you will gain some prestige for having done the project.

Keep on thinking.

[Downtownbrown26]

Great Navel Orange Race
2008 Competition Rules
Objective
The objective of the Great Navel Orange Race is to transfer an orange safely through a required naval route in as little time as possible (maximum 5 minutes). The transfer device will need to be loaded by an operator at the staging area and then have to traverse through the course
with the orange to the finish line. At the finish, another operator will need to remove the orange from the vehicle and place the orange on the finishing bay.

Rules
The following rules outline the general guidelines that will be applied to the competition, please note that any rule clarifications will be made by the course instructor and are final.

Course Layout
The figure below illustrates the basic course layout of the reflection pond during the competition.

Course Description
Check In Area – This area is where your vessel will be inspected for any rules violations and
will be judged on your overall design and construction.
Staging Area – This is where your vessel will be placed into the reflection pond. There will be separate starting gates, and your starting gate will be assigned, at random, after check in.
Orange Bay – At the start of your race, your vessel will not have the orange already loaded; when the race begins you will need to load your particular orange and start your vessel around the track.
Reflection Pond – The course itself will require you to travel from the staging area to the
finishing area. There will be a flexible barrier preventing your vessel from traveling into the fountain (the barrier will be approximately 2 feet tall, will extend approximately 6 inches into the water, and will be quite flexible, so plan accordingly), however, it will not prevent waves or spray from traveling onto the track.

Finish – At the finish line, one of you teammates will remove the orange from your vessel, place it on the final orange bay and your time will be recorded. At this point they should remove the vessel from the water and proceed to the check out table. Note that your vessel does not need to hit the finish wall at any particular point; it simply has to get close enough for your operator to remove the orange. Also note that if your operator enters the water for any reason, you will automatically be disqualified and will receive the maximum time (5 minutes).

Check Out Area – This is where the final judging and score assignment will be completed.
Additionally, all group members will be required to use their CPS for a competition attendance grade.

Detailed Objective
At the start of the race, an operator from your team will need to pick up an orange from the starting orange bay and load your vehicle. Once your transport vehicle has been loaded, it then needs to travel the reflection pond and arrive at the finishing area. Once your vehicle has reached the finishing line, a second operator will need to remove the orange from your vessel and place it on the final orange bay. Your total time will be recorded as the time from when the race is started until your unloading operator has placed your orange on the final orange bay.

Additional Rules
1. All oranges (standard navel oranges) will be provided by the instructor on the competition day. Orange weight will be ¼ to ½ pounds each.
2. The spending limit on the device will be $60.
3. You must bring all receipts of your purchased parts to the competition for your check in.
Online purchases will be allowed, however, you must still be able to provide a receipt of your purchase. All parts used must be counted towards the allotted budget, and any donated parts must have an equivalent RETAIL price associated with it (you must provide proof of your retail price: store ad, online price search, etc.).
4. All vessels must be self guided and self propelled, absolutely no remote control and no string or line-based guidance systems will be allowed.
5. The team must perform all production of the device themselves (no commercial manufacturing). No preassembled parts or kits will be allowed (this includes store purchased boats and boat hulls).
6. Your vehicle must be based in the water, i.e., it cannot leave the water area at any point during the race.
7. The orange bay will be within reaching distance of the staging area. At the start of the race one of your team members must pick up their respective orange from the orange bay and secure it in your vessel. Your loading and unloading time will be included in your total race time, so make sure you account for loading and unloading the orange in your design.
8. Vehicle must transport one and only one orange to the finish line, if your vehicle looses the orange during the race a penalty will be assessed to your performance score.
9. Orange must remain in its original condition during the race, if the orange does not return in its original condition a penalty will be assessed to your performance score.
10. No liquid flammable objects are allowed (including gasoline and other liquid combustible fuels).
11. Solid fuel rockets are allowed; however, if your design is deemed unsafe at check-in, you will not be allowed to race and will receive the maximum time (5 minutes).
12. No animals of any kind are allowed.
13. All designs must be capable of finishing, at most, 4 trials.
14. If each run uses disposable items (i.e. CO2 cartridges, etc), then the cost must be calculated on ALL 4 trials.
15. A list of ALL materials used must be submitted on competition day with receipts.
16. Once the race has begun, no interference will be allowed by any of your team members. If your vessel fails to finish the race, the maximum finishing time of 5 minutes will be given to you.
17. If at any point any of your operators enters the water, you will be disqualified and given the maximum finishing time of 5 minutes.
18. Each team must check out properly by:
a) Turning in their competition sheet.
b) Turning in their final report.
c) Returning the orange to the starting orange bay.
d) Disposing of any waste in relation to the device.
e) Turning in your peer evaluations (individual responsibility).
f) Failure to complete the above tasks will result in a 50% loss of the team’s overall performance score.
19. Additional rules and clarifications will be posted on WebCT.

[Downtownbrown26]

There is the actual rules that we have been given by our professor and his teaching assistants. Hopefully this will help convey everything I was trying to say in my earlier post and can clear up any of my fuzz spots

[Kay9]

Wow. Solid rock fuel IS allowed. I would really want to try that approach.

K9

[marshmat]

Kay9, you can always delete the post if you double-post (click edit, then a delete button will appear at the bottom right of the edit pane).

Solid rocket fuel? Would have to be an A-class motor, because a C would definitely put it halfway across the field. Or make your own... zinc, sulphur and a bit of alcohol might work? (Just kidding, that will DEFINITELY be deemed unsafe to race!)

You're using WebCT? I feel sorry for you... hate that bloody piece of you-know-what....

For steering, it seems you could either bump against the outer wall of the fountain, or build a rudder that you can set at a fixed angle corresponding to a turning radius that has you doing a circle of the appropriate size. Another option might be a stiff wire out to the side that moves the tiller arm when it brushes the fountain wall?

It has to run 4 trials, so simple is good- the more parts there are, the more that can go wrong halfway through the final lap.

[Kay9]

Oranges float. So I guess you could tow the orange.

K9

[Kay9]

Oh heres an idea. Tape a solid rocket motor to the orange with a small fin taped to the bottem of the orange. Fire it off and point at the side of fountian. It might go around 4 times fast but it would go around. Of course it might go over also, but it will be neat to see a flying orange. You would of course lose.

K9

[PAR]

Clearly you have lots of options, including batteries, small electric motors, timers, relays, switches, etc. I'd love to participate in a project like this. It seems a reasonably easy one to complete with several avenues of operational pursuit to follow. The net of course, would be to finish the route with the best time and least amount of penalties.

My thoughts would center around carrying the load (orange) and relatively fast propulsion. Steering would be a timing thing, which could be hammered out in a pool.

Once you get a suitable hull shape, that can easily handle the 1/2 pound load, one that possibly is efficient and easy to motivate, you can arrange a battery driven motor and prop. All of this is simple enough. Then set up some timing runs in a straight line. Say several runs with an average speed worked out. With the speed you can easily calculate the distance you'll cover, before requiring a rudder input.

A quick note to the folks at BoatDesign.net, let Downtownbrown26 get his grade. So far I've not gotten any deeper then 9 grade mathematics, lets not ruin the focus of the course, for the poster.

Downtownbrown26, these things are real fun and force you to think outside the box and incorporate what you've gathered during your stay in school. Success is nice, but development and innovation are just as important. I remember my final for structural, which required a device climb a vertical wall, which had a 90 degree corner in it. We were given a box of stuff and a list of things we could and couldn't so. I thought it was imposable, but did eventually manage to get a device to climb up that damned wall. Mine almost made it to the top and only three others actually did get there.

The point is, there's much to learn from an exercise like this and asking the RC guys and boat design guys how isn't going to further your career, but doing research (like talking to the RC and boat design guys) is just what you're supposed to be doing, before you set off and crush the competition with your latest demonstration, of your engineering abilities.

So, what have you come up with so far Downtown?

[Downtownbrown26]

My original design so far was possibly using foam to create some kind of hull pantoon. I was thinking about using a fan motor and some batteries to power some kind of prop. Possibly two props, since I could have one timed to turn off so that the other one could turn the boat and then have it turn back on so that the boat would straighten out. I also thought about carving a hull either out of foam and some how paint the sides so that it would be more stream line in the water. I am not completely sure of my design though that why I have been posting on this forum asking advice hoping that someone's idea could point me in the right direction for success.

[PAR]

Now you're cooking. Fans aren't the best way to propel a boat, in fact they are pretty inefficient and very slow to cause the boat to respond to steering input changes (they skid sideways pretty badly). Props in the water is a better answer. A pontoon boat is simple enough, though requires the effort of building two hulls the same.

Personally, I'd build one hull. I'd have a relatively long beam to length ratio to permit easy propulsion and use the orange for stability. Think long and lean, with the orange low in the hull, but not so much so that it requires you shape the hull around it, causing additional displacement and drag. Steering with duel props is a fair idea and a faster response then rudders.

You may want to look at skiffs, sharpies, canoes and other high beam to length ratio craft for hull shape ideas. Keep it simple (the hull shape) as I don't think your speeds will warrant working out a full plane shape. A flat bottomed, thin skiff will plane if enough power is available.

Foam is a good material to carve your hull from, though some types of foams will absorb water, making them considerably heavier, pretty quickly, which wouldn't be good. Do some tests or find some "closed cell" foam to get a material that doesn't suck up a bunch of weight. I wouldn't worry about how smooth the exterior surface is, though the smoother the better, your gains will not be particularly significant.

Your props can just dangle off the end of the boat. They don't have to be buried inside and come through the hull bottom. Keep the shaft angle as close to level as you can, you'll get more thrust efficiency this way.

I'll let you work out the timing issues, which should be easy enough over a fixed distance course, once you have a handle on the speed you'll get from you boat.

Stream lining is more shape then surface prep. If you have a reasonably smooth surface, then your hull shape and power on tap will govern it's speed.

Personally, I'd be working with hydrofoils and a cantilevered prop shaft, but I'm a touch odd. Where's Doug Lord when you need him . . .

[Downtownbrown26]

Well I was thinking about using a fan motor to power the prop since i can probably get two fan motors that have setting for high medium and low. I was thinking that during the straight away the both obvious be on high so I could gain speed. Then when the boat goes into the turn turn the left motor on medium or low maybe even completely off so that the boat would be able to turn on a dime. Then somehow have the motor turn back on so that the boat can straighten out. i agree with you about the hull shape. I have been tossing around ideas and even though the pontoon boat seemed easy to build, I dont believe that I would have the kind of turning radius that I am looking for. Another aspect about the pontoon idea that i did not like was that I dont think that I will be able to get it up to a fast speed. If you don't believe that the fan motors will not work can you suggest some kind of cheap motor to use in exchange that would have enough power to turn the props

[PAR]

Fan motors will turn your props, maybe a flexible shaft too. It only has to survive a few hours, much less in actual operation so don't worry about the thing burning up. Some simple experiments with prop diameter and pitch will yield a pretty good propulsion unit(s). I'd go with a two blade prop for ease of building. Make up a few different ones and see which works best on your little container vessel. Don't worry about gear reduction or any of that, just a direct drive shaft with a prop attached to the tail end of it.

Think light weight. Small DC motors are available at Radio Shack or better yet SkyCraft in Orlando (the place with the flying saucer on the roof). In fact, you'll probably be able to find everything at SkyCraft and pretty cheap too.

You can actually get some real small props from the RC guys, try hobbies in the yellow pages (Hobby Shack, in Orlando, I think). These will kick some butt with a high revving motor.

Since you'll have a motor or two, you can easily V belt off the shafts to drive a timer or two, though a little thinking would produce some timed switching.

[Downtownbrown26]

Ok I found DC motors but do have any recommendation which type of motor to use. There are various motors available from Radio Shack. I found a 9-18VDC motor available for like six dollars each, which is easily in my spending limit with alot of money to spare. I am looking for timers and switches so that I am able to turn off the motors and turn them back on. Any ideas? Ive looked on various sights already but Ive never done anything like this so its all new to me. Ive never worked with circuits before so i have not clue where to start. Any way you can do some coaching to help me understand what is needed to do to create these switches and timers so that I am able to shut down a motor and turn it back on so that I can be able to turn the boat.

[Kay9]

I would think your 9V motors could be controlled with a simple flashing light circuit ( available at radio shack ) with a pot to time out the freq of when the motor is on and when off.

K9

[PAR]

You have a motor that is running. If you have this, you have potential for a timer and no need for additional electrics. A small shaft, with a belt on it, turning a substantially larger free spinning wheel can offer a world of options (geared way down to suit your steering needs). The wheel could be a cam or have an actuating pin sticking up though it to make contact with something (like a switch). The whole point working out these issues, doing some testing, then some model development, with an eventual entrant into the race, that incorporates what you've learned and figured out. Other then the motor and batteries, you could do everything else mechanically.

[tinhorn]

Great application for an old-fashioned sidewheeler design! For authenticity, it would have to explode at the end of the race.

Sounds like the biggest trick is navigating the course. Will you be able to make test runs? What will the course be marked with? Going straight up the middle, of course, will give you a faster time than bumping around the outside edge.

Too bad the teammate is required to pick the orange up off the boat. If you could catapault that sucker about eight feet from the finish line, you'd shave off maybe half a minute.

[Kay9]

"Great application for an old-fashioned sidewheeler design! For authenticity, it would have to explode at the end of the race."

Too funny.

[FAST FRED]

The hard part will be the steering system. While a finger or similar to scrape the side of the pond might steer..

It is probable that the land will be warmer than the water.

Could a cheap enough heat sensor be wired to keep away gently from the warmer shore?

FF

[PAR]

How many revolutions of the motor's shaft will it take to travel before you need to start your turn? Can a gentle turn (fixed rudder deflection or natural prop walk) be used to get around the semicircle fountain?

[Downtownbrown26]

Any kind of rudder or prop walk would work it just all depends on preferences. Any suggestion which on would possibly work better?

[PAR]

When experimenting on something as odd as this, little evidence exists, so you're left to simple tests and educated guess work. The rudder would work better at higher speeds then prop walk, but lower speeds prop walk would be more beneficial.

[oops!]

i have no formal education in boat building.....


however....as as far as navigation goes......we can only guess at the design of the course......at this point it seems circluar...scrapping the edge will not work....too many variables....the intermittent motor will work...but how you gonna time it?...gotta be bang on and reliable......id go rudder.....
but you cant fix position it.....

a person could hook up a clock....every time the hand came around...it hits the rudder....after contact...the rudder straightens out via elastic bands...and the craft goes straight again......

the amount of times you turn are calculated by the amount of times the rudder is moved...this is adjustable.......

i would also think a dc 9 volt motor would spin just great for this.....

as far as constructing a hull........get a toy boat......use it as a mould...and fiberglass the thing....release the mould....and...bada bing.....a hull like you want...light strong...you could make several...to test...supplies would be begged from scraps at a fiberglass shop....

just some ideas for you to choose from

[masalai]

If the pond is circular, with a central fountain how about something like "control lines" like on early model aeroplanes held in a circular pattern by 2 equal length "piano wires" and lots of - other way rudder to keep the wires tight. then lots of speed... Quickly re-link wires by paper-clips and re position rudder for equally speedy return trip.... (paper-clips are cheap - only $10 each at Pentagon - old stock I recall)

[PAR]

If you read the posts folks you'd see the fountain is semi circular and that "wires" or other attachments aren't permitted to control any element of the craft.

Timing is an easy thing when you have a battery or motor on board.

http://www.berto-republic.com/blogimages/DSC04808.JPG

It liked doing "U" turns and doesn't appear to have any directional control options. It's rudders show some deflection, likely to counter prop torque. Apparently about a half a dozen actually completed the course last year.

[LegendofZeroOne]

This is a rather interesting topic and Sorry to take a different turn on the subject, but what would be a good way to setup a timer for such a boat? A programmable timer would be nice but I don't have much experience with circuits and am wondering if someone can help me.

I want to do a similar boat design (self propelled, self guided) to make its way through a water obstacle course by leaping over the obstacles but am not sure how to setup a timer. Sorry for intruding on the original post topic but the design restrictions were just too SIMILAR!