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[Cklasse]

Ok, I have finally decided that this project may be feasible after communicating with all the nice people here in the forum.
This is an impulsive buy for me when I was in the hobby shop one day and this will be a build posting by someone new to rc and new to boat.

The conversion scale model is a 1/72 Airfix Severn Lifeboat. The hull and everything (almost) weigh as much as the water it displaced and looking at the waterline, I have to remove plastic in order to accommodate the rc electronics.


This is the kit


a small boat

[Cklasse]

Deck space inside superstructure is cut, as much as I can go. This reduced the weight by a good 10 grams, next is to thin the hull and hopefully I can shave another 10 grams.

[Cklasse]

My slow progress....

Cutting out everything not needed in the superstructure and thinning the wall to save weight


Prop tube made from aluminium tube, 1/16" internal diameter to fit 1/16" weld filler wire prop shaft

[Cklasse]

I have planned to access the internal by lifting the upper superstructure but found it near impossible to do so after assembling the parts.



So it's plan B in a haste. I decided that I shall lift the whole superstructure from the deck to access the internal of the hull. A wall is needed to prevent water spilling inside was built using plastic sheet.



Next will be the assembly of superstructure with painting. I am still waiting for my receiver to arrive from Hong Kong, and that will be the test for the drive system.

[Martin (Admin)]

What motors and speed control will you be using?

[Cklasse]

PLan to use 2 modified micro servo as the driving motor for 2 screws and one similar micro servo for the rudder. All will be linked to a Spektrum AR6100 receiver. I have put in a post in the battery thread to ask for a suitable lipo battery to connect to the receiver.

I am skipping any BEC or ESC to minimise the weight. Done a water test and found that the boat is now at the right waterline level. I think with more parts assembled, paint and a battery thrown in, the boat will be slightly below the required waterline. I may have to adopt the advice of letting the rudder swivel free without a servo to reduce weight.

It may work since I will be driving the boat with 2 channels like driving a tank.

[Cklasse]

Finally decided on the setup for the boat and this is the how much the boat will sit in my frying pan 


The screws driven by 2 micro servo, a Spektrum 6 ch receiver (I know it's overkill but this is the only one I can find at a low price and small enough) and 4xAAA battery.


Made a raised and angled platform using plastic sheet for the motor to stick on.


Bottom of hull spray painted. Since the tube and shaft has a same diameter, I just squirt in some grease to fill the tiny gap to waterproof seal it. Will go for a trial run in my numerous condominium pond to test the driving soon.

[Wasyl]

Pond????it looks like a watering hole at the edge of the jungle,are you sure there,s no crocadilians in there {-)or minature boat eating fish,

Wullie

[Cklasse]

You are almost right about the jungle part, it's a Jungle theme condo with ponds and bronze animals scale 1/1. How about these other ponds in my condo?
Elephants?

[Cklasse]

My lipo and other stuff finally arrived in the mail and I can put every component together to see if they work.

Made a battery tray for my new lipo.


Lipo sit on top of prop tube to be as low as possible. BEC for the lipo attached to bottom of deck and receiver attached to superstructure.


Here's how it looks when put together in the final stage.




One strange thing happened after I have decided to use a lipo for the power instead of AAA batteries. The left and right screws are to be driven by the Tx throttle and elevator stick. However, with this lipo plugged in, the throttle stick is able to run both screws (with elevator stick still in neutral) and the elevator stick controls only the left screw. In this unexpected setup, I can now use the elevator stick to control the direction of the boat by altering the speed and direction of one screw.

Ok, so much for the drive. The boat now sits slightly below the waterline. Shall be doing a sea trial (pond trial) after I have finished painting the boat.


 

[Cklasse]

Finally launched the boat and did a "sea trial". I am surprised that the 2 tiny servos can push the boat along pretty fast, at least it's faster than I had expected it to be. Now to fix up the little details of the boat and it is ready for the big pond.

[Cklasse]

"sea trial" for the boat without the deck details. Water displacement is too much for the boat, I will need to change a lighter battery.

[Cklasse]

Here's the video of the trial.
http://www.youtube.com/watch?v=iGokeojyNUE

[Shipmate60]

She looks good on the water.
But the water is so clear I kept expecting her to run aground.

Bob