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Old Nov 17, 2014, 09:47 PM
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United States, AZ, Tucson
Joined Nov 2010
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Here she is in all her glory!

First and foremost, everything besides electronics and prop shaft are 3d printed. Secondly, I wanted to use parts I had around the house, hence the rather large motor.

Weighing in at 165g, it is a bit heafty. However if it gets on plane just fine, it should move quite well with the available 100 watts.

Future changes will include a change to the rudder and its geometry. Because of the current rudder, I did not have the necessary room to have a reasonable right deflection. Secondly, because of the rudder offset, it has a bit more travel than I would like. (when turning left, the rudder is about 2x as far away from the boat as full right). Also, I need to extend the prop shaft guide tube. The front opening currently sits level with the waterline, obviously a problem when just sitting there. That being said however, the leak it slow, and I don't see the boat sinking in any less than 7-10 minutes. Further more, by extending the rudder and providing more clearance, it will allow me to stretch out the driveline a bit more to try to get it out of the bad and turbulent water coming off the back of the tub.

Also, I plane on doing my best to lighten up the sponsons, and aft floats to help it sit just a tad higher.

With a lighter 2s setup and a smaller motor, this thing can easily weigh in at 95-110g. Keep in mind I have a 500mah 3s, 10a ESC, and 1806 multirotor motor.

Current setup is:
Maytech 1806 2300kv Motor
Turnigy plush 10a
6g servo (not necessary at all, way overweight)
2mm bicycle spoke
500mah 3s 20c battery
Orange 4ch Air RX
3D printed prop (3blade 20mm and 2blad 25mm)

As far as fit and finish goes, I am very pleased. All the major parts fit flawlessly. The sponson fit snuggly on the arms, the arms fit snuggly into the tub, the tub halves fit snuggly together, the aft floats fit snuggle and perfectly straight, rudder fits into the rudder mount, and the OD of the prop shaft guide tube fits perfectly into the tub. The small things that need adjusting were purposely printed small tot ensure a PERFECT fit. These include the prop mounting hole (which needs to be drilled perfect so that they self-tap), prop shaft guide tube (again, needs to be perfect to avoid slop), and motor mount to shaft coupler (again, needs to be drilled perfect to avoid slop.)

Ps, this is all overkill. I could drop down to a 360mah battery and save quite a bit of weight instantly (almostt 30g), I could drop from a 6g servo to a 2 or 3g servo, for an approximate 130g even. Thats all with the same motor etc! If I dropped to an 8g motor and 6a esc that would be another ~20g or so, resulting in a 110g boat, very easily.

PSS, If this planes out just fine, I will consider "heafty" boat mods which would consist of slightly wider sponsons, and slightly wider aft floats to help raise the waterline a bit. A small increase in these fields could result in a significant change...
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Last edited by Jwmflying14; Nov 17, 2014 at 10:01 PM.
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Old Nov 18, 2014, 01:42 AM
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Amp Abuser's Avatar
Joined Dec 2007
1,459 Posts
Your rudder is tilted so far back it will cause lift and turning is reduced
Front turn fins are too big and will cause drag and will cause lift if the rigger is going fast enough. Prop is too close to the tub and will cause the tub to run wet ie slower. Of course none of the above matters if you don't have enough power to run fast enough to pop up on plane.

I did some doodles
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