this is one of those projects that a few months ago I'd never have thought about, after a video popped up on my youtube feed showing how to make 3D printed radio control jetboats, and there are plenty out there and you can get ready to run ones cheap enough to buy (from less than £50, but I dont think the batteries will be much use)
after spending a while thinking about them I decided to make one as the jet drives are cheaply available,
if you're wondering how they work, they suck water from under the boat and thrust it out of the back, and one of Newtons laws says it should move forward. I'd just have to make a hull to stick it in with the electronics bits. so after a quick think I had a look on ebay and found you can get Playmobil boats to cut up and play with. the speed boat is 10" long and the police boat is 11" long
so that was the police boat at the back, and while looking for that I got distracted by the little speedboats with the outboard motor, and thought that would be another little project to make a tiny working outboard motor. Ive now got a few of these to play with as they can be be had for £4 to £8 inc postage on ebay.
so that's two project boats to make and I thought I'd better get on with another project which was to fit a couple of ducted fans to the hull of a 1/72 scale Vosper Motor Torpedo boat.
so I got the completed hull bottom and ducted fans and thought about how to fit them to turn it into an airboat, at the same time I had one of the Playmobil boats to hand and thought that the ducted fans on on the back of that would look pretty silly (and the hull shape may be better for playing with on a lake). so that became a third Playmobil boat to convert to radio control, and this is the first one that Ive been working on.
With the radio control side of things, I run single LIPO or Li-Ion batteries so all my models work off a nominal 3.7V and used brushed motors. so a fir while ago I go a paid of 30mm ducted fans off ebay.
and between them they have 90 grams of thrust. the motors on them are 20mm long, 8.5mm diameter and draw 6 amps on fully charged batteries.
the speed controllers Im using are designed for powering motors that draw up to 1 amp and are reversible
but by sticking a mosfet on them, can be converted to 20 amp forward only
as these are children's toys they arn't supposed to be taken apart. the top is stuck to the bottom, so to separate the top of the hull from the bottom I had to run a knife along the join, then cut a section out of the hull ( this was going to happen anyway) as there are a couple places where the top is stuck to the bottom and this needed to be attacked with a chisel
and a standard hull on the left compared to one that has a bit of extra plastic removed (and radio control gear fitted)
the blue part on the top of the boat is impossible to remove without attacking the top with a dremel to remove the double skinned section and this clips into place, so originally I was going to attack the top of the hull to the bottom with rare earth magnets, but now I can glue them back together and have the top section clip into place as the ducted fans and radio gear would be stuck to it (I would still need access to the battery).
I needed to mill some slots in this section to temporarily fit the ducted fans to have a first test ( I know I shouldn't be using a milling cutter in drill chuck, but I do sometimes for very light work).
so that was ready to have a test play on a lake, and it went well enough, (and didnt sink). the wires to the ducted fans do get warm, not surprising really when they are drawing 6 amps and only 0.7mm diameter (including insulation)
2.4GHz 4CH RC Boat High Speed 16km/h Water Jet Boat Remote Control Boat for Kids | eBay
Cope with complex scenarios with ease. Strong performance: With 7.4V 800mAh 10C battery and 370 motor, the maximum speed is about 16km/h, and the high-speed sailing is about 11 minutes. Cool lighting.
www.ebay.co.uk
after spending a while thinking about them I decided to make one as the jet drives are cheaply available,
RC Pump Spray Water Servo Jet Boat Thruster Propellers Pusher 380 Brush Motor | eBay
Jet Thruster. 380 Brush Motor. 6, The distance between the mounting hole of the motor base is 16mm, which is suitable for the installation of 380-390 brush motors and 2040-2445 brushless motors. Shaft Diamter: 2.3mm(circle).
www.ebay.co.uk
if you're wondering how they work, they suck water from under the boat and thrust it out of the back, and one of Newtons laws says it should move forward. I'd just have to make a hull to stick it in with the electronics bits. so after a quick think I had a look on ebay and found you can get Playmobil boats to cut up and play with. the speed boat is 10" long and the police boat is 11" long
so that was the police boat at the back, and while looking for that I got distracted by the little speedboats with the outboard motor, and thought that would be another little project to make a tiny working outboard motor. Ive now got a few of these to play with as they can be be had for £4 to £8 inc postage on ebay.
so that's two project boats to make and I thought I'd better get on with another project which was to fit a couple of ducted fans to the hull of a 1/72 scale Vosper Motor Torpedo boat.
so I got the completed hull bottom and ducted fans and thought about how to fit them to turn it into an airboat, at the same time I had one of the Playmobil boats to hand and thought that the ducted fans on on the back of that would look pretty silly (and the hull shape may be better for playing with on a lake). so that became a third Playmobil boat to convert to radio control, and this is the first one that Ive been working on.
With the radio control side of things, I run single LIPO or Li-Ion batteries so all my models work off a nominal 3.7V and used brushed motors. so a fir while ago I go a paid of 30mm ducted fans off ebay.
Low Voltage 3.7 - 4.4v EDF Unit for Micro, Mini Model Aircraft Indoor & Backyard | eBay
Super Micro 30 - 6 blade 30mm EDF Ducted Fan Unit with 8520 Brushed. You will not get performance if you use a low C rated cell. Item: 30mm EDF Unit with 8520 Hollow Cup Motor. 1x Super Micro 30 -30mm EDF Ducted Fan Unit with 8520 Hollow Cup Brushed Motor.
www.ebay.co.uk
and between them they have 90 grams of thrust. the motors on them are 20mm long, 8.5mm diameter and draw 6 amps on fully charged batteries.
the speed controllers Im using are designed for powering motors that draw up to 1 amp and are reversible
0.58£ |Micro 1a Rc Esc Diy 5v Dc Brushed Motor Speed Controller Motor Reducer Micro Motor Drive Module Two Wire Brush Controller Esc - Parts & Accs - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
but by sticking a mosfet on them, can be converted to 20 amp forward only
as these are children's toys they arn't supposed to be taken apart. the top is stuck to the bottom, so to separate the top of the hull from the bottom I had to run a knife along the join, then cut a section out of the hull ( this was going to happen anyway) as there are a couple places where the top is stuck to the bottom and this needed to be attacked with a chisel
and a standard hull on the left compared to one that has a bit of extra plastic removed (and radio control gear fitted)
the blue part on the top of the boat is impossible to remove without attacking the top with a dremel to remove the double skinned section and this clips into place, so originally I was going to attack the top of the hull to the bottom with rare earth magnets, but now I can glue them back together and have the top section clip into place as the ducted fans and radio gear would be stuck to it (I would still need access to the battery).
I needed to mill some slots in this section to temporarily fit the ducted fans to have a first test ( I know I shouldn't be using a milling cutter in drill chuck, but I do sometimes for very light work).
so that was ready to have a test play on a lake, and it went well enough, (and didnt sink). the wires to the ducted fans do get warm, not surprising really when they are drawing 6 amps and only 0.7mm diameter (including insulation)