need help building 50 dollar or less boat - RC Groups
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Feb 24, 2005, 01:26 AM
Registered User

need help building 50 dollar or less boat

I have to build a boat for one of my classes for 50 dollars or less using only local stores and we can use pawn shops. We have to purchase all the parts and cannot use any we previously own. The boat has to be able to drive across a 100-200 foot pond while 5 others are going, pick up an orange, and bring it back and only have the orange cross the finish line. Also, we cannot use a rudder. If anyone can help me, it would be greatly appreciated. Also, if anyone knows of a way to change a cheap recievers radio channel into something less common that would be good to since we don't want interference from the other people.
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Feb 24, 2005, 09:14 AM
Tinkerer in Training
RGinCanada's Avatar
Does it have to be R/C? For $50 I would explore spooling out phone wire. It makes the on board setup simple, and keeps costs down... You could basically use a 2x4 with two submerged motors and a 'Y' fork on the front to push the orange. Even the power source could be on land...

Once it gets to the other side and collects the orange, use the spooled wire to retrieve it!

Not elegant or pretty, but cheap and practical!

Have fun!

(I've added my 3 minute CAD design for your laughter... The control wire would be attached at the mast top to ensure that during retrieval the orange crossed first. The middle fin on the bottom is for directional stability)
Last edited by RGinCanada; Feb 24, 2005 at 09:33 AM.
Feb 24, 2005, 11:46 AM
Registered User
im going too post the exact rules:

1. The instructor will supply Oranges (Standard Navel Oranges).
2. Orange weight will be ¼ to ½ pounds each.
3. The spending limit on the device will be $50.
4. All parts of the device must be purchased at a local store and you must bring all receipts. NO ONLINE PURCHASES!! All parts used must be counted towards the allotted budget; with the only exception being a remote control (remote controlled objects or vehicle parts are not included in this exception.
5. No string or line-based guidance systems will be allowed.
6. The team must perform all production of the device (No commercial manufacturing). No preassembled parts or kits.
7. The device cannot be constructed using any type of glue. (Including rubber cement and epoxy).
8. Epoxy used in the application of fiberglass is allowable, but the epoxy by itself cannot be used in a glue-like manner.
9. Launch vehicle must be free floating, or, if stationary, must be based in the water.
10. Navel oranges will be released approximately 1 ft from each other (center to center), and will be allowed to float freely after the start of the competition.
11. Vehicle must transport one and only one orange to the finish line.
12. Orange must remain in its original condition, and without any covering upon crossing the finish line.
13. No open flames allowed.
14. Teams must predict their transport results using MathCAD or Matlab
15. No movable rudders of ANY kind are allowed.
16. All designs must be capable of finishing 4 trials
17. If each run uses disposable items (i.e. CO2 cartridges, etc), then the cost must be calculated on ALL 4 trials.
18. A list of ALL materials used must be submitted on competition day with receipts.
19. Each team must check out properly by:
a. Turning in the competition sheet
b. Returning the orange
c. Disposing of any waste in relation to the device
d. Checking in with the CPS transmitter (Individual Responsibility)
e. Failure to do the above tasks so will result in a 30% loss of the team’s performance grade.
20. Any student pushing near the finish line will have 10 seconds added to their time.
Feb 24, 2005, 12:15 PM
Sea Dragon-Lover
Umi_Ryuzuki's Avatar
Do you have the Remote control, and servos already?
And Am I correct in understanding that A remote is not part of the $50 budget?

All parts used must be counted towards the allotted budget; with the only exception being a remote control (remote controlled objects or vehicle parts are not included in this exception.
But a boat, or propeller, or drive shaft are part of the budget?

A couple motors
Airplane propellers
pink foam or styrofoam packing
some nails and screws, and two hose clamps
some plywood or 1x3

I think it could be done.
Just turn RGinCanada's design upside down...

The "NO Glue part makes it a bit tricky, but nothing the screws and hose clamps can't solve.
Last edited by Umi_Ryuzuki; Feb 24, 2005 at 12:43 PM.
Feb 24, 2005, 02:02 PM
Historical Shipwright
Duct tape, lots of duct tape.....
Feb 24, 2005, 02:14 PM
Registered User
the remote isnt included, but the reciever, motors, and servos are included. Also, i dont think an airboat would be powerful enough to push an orange. We had that idea originally. Right now we are looking at making a trihull boat and turning the outter 2 hulls and the center hull will have the motor. or were thinking about turning just the motor and shaft...but were still having trouble figuring out how to get radio equipment and keep it under 50 and not have interference. I think the professor didnt think this through well enough, at least 250 boats will be running throughout the day and people will be smart enough to use their radios to mess up other people.
Feb 24, 2005, 02:41 PM
Registered User
Does your Prof. permit collaboration for ideas outside your team members? If no, asking for guidance here just might amount to 'cheating'.
Feb 24, 2005, 02:43 PM
Tinkerer in Training
RGinCanada's Avatar
I'm suspecting that an orange probably floats with only 5-10% of its volume above the surface. (GEEZ, why didn't I pack an orange for lunch today??) so the pushing device will need to be submerged by 3" - 4", or the vehicle might just run over it.

Umi, do you think an airboat would perform faster and be more manoeuverable than a "conventional" prop boat, considering the power required to shove around the mostly submerged orange?

It sounds like a fun competition... Now that you've got us interested, you'll have to post photos of your design and the competition!

The collaboration question is a good one... Its not in the rules, though
Feb 24, 2005, 04:26 PM
Registered User
Maybe a little off-topic, but what are you studying?
Feb 24, 2005, 05:28 PM
Registered User
im studying aerospace engineering, and we were not told we couldnt collaborate outside our group. We were told we needed to research the stuff. Ive built 5 radio controlled sailboats and 1 radio controlled hovercraft so i know some stuff, but i dont know how i can adapt a cheap radio control receiver and servo into something good for a very low cost. That seems like it will be the hardest. And also, there will be 10 boats running at the same time.
Feb 24, 2005, 05:47 PM
Registered User
Cool, I plan to study Aerospace Eng. at Ryerson U. in Toronto.
I have one suggestion about keeping the cost low and getting some good stuff in your boat.

You could buy all the stuff you want no matter what the cost. Then go to your local pawn shop and ask the store shop to say that he sold you the stuff for $10. No one could ever proove how much you paid, as long as you are good at lying.(get him/her to make up some fake receipts)

I know it sounds bad and all, but sometimes thats what you have to do to get what you want.
For example I had an interview for the Air Cadets to get my flying scholarships and they asked me stuff about how I contribute to my community...blah, blah, blah etc... I just made up a whole bunch of cr ap to make them think I was like a super kid or whatever.

Good Luck,

Feb 24, 2005, 09:44 PM
Registered User
" I know it sounds bad and all, but sometimes thats what you have to do to get what you want ... I just made up a whole bunch of cr ap to make them think I was like a super kid or whatever. "

Glad to know you you have the decency to stop short of raping, pillaging and burning and the guts to acknowledge that you're a dud.

Here some free advice -- Your history lives with you .. don't do anything that you will regret or anything that can come back to haunt you when you least expect it. Someone will always remember the most inane skeleton in your closet and will remind you (and the public) when it least suits you. My advise to you and your generation is to play it fair and square. In my day job I am a lawyer -- I have seen many people's careers burned by what they claimed was 'youthful indiscretion.'
Feb 24, 2005, 09:53 PM
Registered User
thats nice advice for him, but do you have any for my current project?
Feb 24, 2005, 10:02 PM
Registered User
Sorry. I would like to help you but by definition I think 'research' means that you and your team dig up the facts and information for yourselves and apply your knowledge to the problem. Asking others how to do it is not reseach in my book. Its a shortcut that deprives you of the education that your Prof is trying to impart to you.
Feb 24, 2005, 10:15 PM
Registered User
Research can use other people. Reasearch requires I determine what I want to know about and look up solutions for it. Using people is first hand research, Reading books can be second or third hand research and webpages can be even less direct from the source. Also, this is for a 1 credit hour class that has 900 people in it. It isn't expected that we are genuises in the subject. I can build a radio controlled boat that can do this without a problem. The problem i have is how to get it on a frequency that no one else has with this budget. Since there are around 200-300 groups, and we cant afford a radio that we can change crystals on, there will be lots of interferece since the radio shack type things have a very limited range of frequencys. So I am doing research in trying to figure out a way to change the frequency.

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