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engineering project help
hey guys,
im doing a semester project for engineering where we have to build a boat that carries a navel orange around a pond. there really is no restriction except that the boat cannot be store bought, and it cannot use human power at all, it also cannot be radio controlled and i know this is a r/c forum but i was hoping some of you could help me with the actual motor, prop, shaft, and battery side. oh and the spending limit is $80 total. what do you guys suggest for a hull design? i was thinking maybe carving out styrofoam and coating the outside with fiberglass resin or bondo? motor? only thing i have now is a "super speed hobby motor" from radio shack www.radioshack.com/product/index.jsp prop and shaft? i was thinking maybe this? www.hobby-lobby.com/flexible_shaft_coupler_4mm_5mm_543_prd1.htm and www.hobby-lobby.com/10.2_prop_shaft_6mm_od_3_or_4mm_shaft_498_prd1.htm and www.hobby-lobby.com/50mm_r_104_prd1.htm battery? what would be more powerful a 8-pack of AA (12 volts) or one of those r/c battery sticks 7.2V/2000mAH also i think im just going to use a toggle switch for on and off. my biggest concern is what kind of gearing it needs. would it be fine just for a direct drive from motor to prop or maybe get one of these? www.hobby-lobby.com/universal_marine_gear_drive_2.51_86_prd1.htm what would be the best layout in the boat so the motor doesnt get yet but the prop is efficiently placed? throw any ideas you guys have. any help would be greatly appreciated! remember budget is 80 bucks thanks in advance! |
RE: engineering project help
ORIGINAL: justacobalt hey guys, im doing a semester project for engineering where we have to build a boat that carries a navel orange around a pond. there really is no restriction except that the boat cannot be store bought, and it cannot use human power at all, it also cannot be radio controlled and i know this is a r/c forum but i was hoping some of you could help me with the actual motor, prop, shaft, and battery side. oh and the spending limit is $80 total. what do you guys suggest for a hull design? i was thinking maybe carving out styrofoam and coating the outside with fiberglass resin or bondo? motor? only thing i have now is a ''super speed hobby motor'' from radio shack www.radioshack.com/product/index.jsp prop and shaft? i was thinking maybe this? http://www.hobby-lobby.com/flexible_...m_543_prd1.htm and http://www.hobby-lobby.com/10.2_prop...t_498_prd1.htm and www.hobby-lobby.com/50mm_r_104_prd1.htm battery? what would be more powerful a 8-pack of AA (12 volts) or one of those r/c battery sticks 7.2V/2000mAH also i think im just going to use a toggle switch for on and off. my biggest concern is what kind of gearing it needs. would it be fine just for a direct drive from motor to prop or maybe get one of these? http://www.hobby-lobby.com/universal...51_86_prd1.htm what would be the best layout in the boat so the motor doesnt get yet but the prop is efficiently placed? throw any ideas you guys have. any help would be greatly appreciated! remember budget is 80 bucks thanks in advance! I'd imagine a cat style hull would be decent enough. A brushed 400-600 series can would be optimal. Similar to [link=http://www.hobby-lobby.com/speed500.htm?pSearchQueryId=1313996]THIS[/link] Using a brushed motor with a higher listed voltage rating is equivalent to lowering kv. A motor with a lower kv will allow you to run a larger prop. You will want to run direct drive. The 7.2v pack will ouput more power than 12v AA's. Use the 7.2v pack. Where P = I V. Not a Cobalt SS? Ryan |
RE: engineering project help
Fiberglass over styrofoam will melt. Since this is just a school project I would carve it out of the blue styrofoam and use sandpaper to sand it smooth. Its not like you are building a race boat. I agree with Ryan- do something like a cat.
KISS rule here... Go for the NiMh batts, a speed 400-500 type motor will be OK. For props I would keep it small to keep the speed down. Unless you have a real good reason to go fast DONT. |
RE: engineering project help
well i got the brushed motor from radioshack today 9-18 vdc with 2 amp limit. also got 8 AA's to power it. if its not enough ill just get a battery stick. where do i get this blue stryrofoam stuff? the project is for speed and its the boat that can get the orange around the pond the fastest (about 300 feet)
and yes ryan a 2009 ss with a gt28 turbo swap @ 25 psi. i just used the same username as the car forum im on thanks for the help |
RE: engineering project help
Well hopefully that motor has enough power.
Blue Styrofoam can be bought at home improvement stores. They have some 2" stuff that would work well. Since this is for speed I would still go that route and I would use pine dowel rods to reinforce/hold it together. Using spray glue (appropriate) to bond the foam. If you get enough info build/use a hot wire method to speed up the process. |
RE: engineering project help
blue stryofoam it is. ill keep you guys updated. oh yeah the motor i got is 17,000 rpm which is alot higher than the motors you showed me. would this mean i need a small prop because the motor probably doesnt have much torque?
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RE: engineering project help
Yes, to be honest I don't think you have much power there. Even with the smallest prop, I think your motor would see more then 2A. If it runs for less than a minute or so it may stay cool enough. Also, If your motor doesn't draw all that much current the 8 AA's @ 12v will provide more power than a 7.2v battery. Just to keep in mind.
So an SS/TC wasn't good enough? You had to swap the stock out for a Garrett. :D That's a big turbo, you must get lots of lag with that setup vs stock. When do you see full boost, almost 5000 RPM? meh, I have to wait until 6800RPM before I see what can be considered a minor bump in power. Ryan |
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