BoyntonStu

In progress, but you can see where I am heading.

The split is 10"/15".

I don't know yet how it will balance so bow or stern is in doubt.

My 'hull' will be a plastic storage container.

The periscope up/down is yet to be designed.

Approximately how much current will the receiver and servos require if given 5 Volts from a chip?

I am looking for a small ducted fan and reverse able ESC.

BoyntonStu

air-madness

Well, first, wouldn't your noodles be considered the hull (the flotation portion)? Do mean, perhaps, the deck with the storage container? Receivers and servos will function above their recomended range, and below; servos just lose torque and speed and receivers lose range when the voltage is lowered. The ducted fan, well, I wouldn't even mess with that since the boat isn't real streamlined (no offense). Ducted fans are not that efficient, especially for boat applications; they lose power rapidly when confronted with oppsing forces that are greater than the weight of the craft, i.e. water force (resistance) will be as great as the craft weight or more bringing the total resistance far above what ducted fans are capable of reliable moving. Basically, once the craft got moving it would be time to replace, or recharge, the battery (it would get drained very rapidly with the focres of resistance).

Here's what I would do: (1) Buy a 400 (prferably a 550) size motor for an rc car (perhaps a 21x2 turn motor for great power and run time efficiency); (2) Buy a prop adapter to fit onto the motor shaft (rc airplane); (3) Experiment with various rc plane props; (4) Use an rc car speed controller that is capable of turning the chosen motor. Looks like it will float well. If you want speed, I would change some of the hull desing to accomadate for it. You will have far greater results for your idea using the above items than a ducted fan platform. You will be able to go slow or fast, unlike a ducted fan. ducted fans do not produce high torque compare to their propeller cousins. You can do what you wish, I just hate seeing people waste money and seeing them get frustrated when they do so.

air-madness

I forgot to mention/reply to the reverse portion of your question. An airplane prop will give you far greater ability to go in reverse, whereas a ducted fan is basically nil. Although an airplane prop will not function w/the same efficeincy in reverse as it does spinning it's intented rotation, regardless of what people say, but it will give you a little bit of power enough to go in reverse.

Some people think simply reversing an airplane prop will allow for a "pusher" type platform; this simply is not true at all, unless one is using a variable pitch prop (variable pitch function on the same principle as helicopter blades).

BoyntonStu

I agree with most of what you say.

Please consider this for a slow moving noodle barge:

From:

http://www.rcuniverse.com/forum/m_5776303/tm.htm



Motor is a brushless RC SMART 4890Rpm/V
RC Smart 30A Speed Controller
11.1v Lipo 2200mAh
Ducted fan kit
Does this:
http://www.youtube.com/watch?v=7V4dniJUhag and this:

http://www.youtube.com/watch?v=g2Df_3Td_HQ


Seems to me that for a little bit of push a ducted fan may be enough.

Thanks,


BoyntonStu

boatman1

Ok this is going to be a video platform
Is this going to be used in a pool or out on a lake or big pond ?
How much video equip. going to be used on it ?

If you use it out on open water will the duct fan have enough thrust to
bring it back if the winds pickup & it goes out yonder ?

I like your idea but i think a single eletric ductfan is not enough to handle
that load of pvc pipe & foam noodles if there is any type of wind

Now 2 or 4 ductfan units powered by a 12 volt gelcell
would do the trick

BoyntonStu

12 Volt gelcell it will be! At least 5 Ah.

Would a 1-2 pound thrust be enough on a fairly calm lake in my backyard?

It is approximately 600' x 2,000'


Would this combo do it?

http://www.unitedhobbies.com/UNITEDH...idProduct=4708


BTW Please explain 12turns vs 18 turns ( lower number of turns equals less resistance and higher current FOR THE SAME SIZE WIRE) thus more power. Correct?

Is there a standard?

And: What defines a 500 motor, a 350 motor, etc. Is there a chart?


Stu

air-madness

Sure. The turns in a motor relate to the amount, or number, of times the copper wire is wound around the arpature inside the motor. The size of the wire relates to the second number in motor specs. The size of the motor, for exapmle "550" relates to the overall size of the can (the can is the outside visible portion of the motor). When the can is bigger so to are the internals, generally. To give you an idea, a 550 motor is the typical spec motor for 'hobby grade' rc cars/kits. The smaller the number, the smaller the motor, so on and so forth. Now, brushless motors are a differnet ball game. They tend to do their specs off of voltage, watts, and etc; they do not follow the same criteria as a brushed motor when comparing the two.

An 18 turn vs a 12 turn will prove to have more torque, whereras the 12 turn will yield lower torque, but have a higer and faster rpm band. The lower the turn, the more current that is sucked out of batteries, and faster too.

martno1fan

interesting build is there any reason you used two rows of pool noodles as floats?,the reason i ask is im currently building a sail boat 3 ft long into a trimaran and im using one float each side.im using foam pipe insulators for the outrigers or floats.im sure just one each side would be enough that way you will have a nice 3 pointer.the build im doing is a tried and tested design by a guy here in the uk and it works really well.ill post a pic of mine so you can see what i mean.its surprising how bouyant those noodles are !!.

BoyntonStu

Thanks, great minds think alike.

My project is more liked a slow moving barge than a boat.

In addition to te RC gear and dual motor driven air props, it is designed to carry a 4 pound 12 V SLA, 42 LED video camera, transmitter, and a raiseable/tiltable periscope,

It is very adaptable. If a one row of noodles will suffice, I can remove the second.

BTW, my intention is to fill the unsealed PVC pipe packed with ground up foam.

If the 2 rows of ~2.25" foam noodles are not buoyant enough, I can replace them with ~3-3/4" noodles, or perhaps even a single.

Please send us your photos.

Stu

My shopping list:

4-6 channel system
2 brushless motors/reversing esc, props or ducted fans.
2-Servo winch

Anyone have dust collectors?

martno1fan

ill take a few pics in a few mins mate now im understanding what you want so your intention is a floating platform rather than a boat?
why not make it a water prop and rudder it will be more manouvarable and better to controll than an air boat.just get a 540 motor and a mechanical speed controll used in cars and it will be good to go on 7.2 volts.

martno1fan

heres the tri im going to attatch the floats to this sail boat but i need to remove the keel fin and bulb and replace it with a smaller fin with no weight.i sealed the ends aty the front by cutting a v then gluing the ends to form a bow shape then selaed it with cling film and tape.the other end is sealed with a foam off cut glued on .the attach points are plywood in a triangular shape put into pvc tube 3 " long anf glued in then i split the foam to insert the tube and taped it in place.

BoyntonStu

I agree except that the fishies and the alligators will not like the noise and disturbance.

I want to video them as stealthily as possible, hence, airboat.

BoyntonStu

I 'lubed' the 1/2" PVC with H2O and it went into the noodle with a hard push.

martno1fan

so its fish and aligators your going to film sounds very interesting my lad loves nature programmes etc.id still go with a water rudder though as it will give better turning at slow speeds.it would spin in its own length with a water rudder also rather than have a motor that spins in reverse why not have one motor facing front and one back so you can use that to reverse using a third channel?.ive never tried an aero prop in reverse but maybe it will work well enough to reverse the boat maybe not.i think having one motor to push you forwards and one back would be a good way to manouvre the boat well.make the rudder wide to help with turning and it will spin on a dime !!.