Jet Propelled Radio Controlled Duck

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Introduction: Jet Propelled Radio Controlled Duck

40+ years ago I wanted to get a radio control boat and use it on the nearby Park Lake, however the Park Keeper made it quite clear that no boats would be allowed. So I hatched this plan to disguise a boat as a duck. Slight drawback was the price of radio controls and boats, the only one I remember was a Swan Macgregor Digimac 1 channel radio, which probably cost a years pocket money. At some point about 25 years ago I did buy some plastic ducks, but nothhing ever came about, so fast forward to today, and I thought it was about time I realised that dream and make a radio control duck.

Aware of the amount of weeds and flotsam I also decided that instead of a propeller and rudder, I would use one of the cheap 15mm Jet Drives that can be bought really cheap.

Step 1: 3D Printed Hull and Electronics Bay

First step was to design and print a hull and place the jet unit into that. I wasnt able to find any dimensioned drawings of the units, so painstakingly had to measure and make plenty of test prints until I had something that worked. I knew that I would also need a lot of silicon sealant to make it waterproof, but the dimensions turned out to be pretty correct. I also printed up a smaller box that would sit inside the hull to contain the electronics and provide a secondary barrier to the water in case there were any leaks as well as to keep things tidy. I printed the hull and box in ABS, but pretty much anything would do the trick.

Step 2: Test Fit

So here are some of the many test fits to see how everything goes together. I also needed to print a small sled to hold the servo that would pivot the nozzle for direction control. These units also come with a water cooling jacket, but I've decided not to use this as I'm only running this at very light throttle settings. The other thing to line up is the servo control rod as it has to pass through the hull.

Step 3: Cut the Duck

This was a fairly easy operation as I had already designed the hull to fit within the duck. The hull was designed with a lip and so I just placed the hull on the duck and traced the edges. A scalpel was all that was needed to cut through the decoy body and the hull was pressed into place. Silicon sealant would eventually glue the two parts together.

Step 4: Battery Case and Wiring

I'm using a pretty standard remote control set up here with a 2s LIPO battery and an Orange RX in conjunction with a DX6i transmitter

The servo is just a cheap 9g servo and some brass rod for the push rod to act as the rudder. For a speed controller I had plenty of these simple 10A ESC controllers with a built in battery eliminator. Just to keep things safe, I'm also using a LiPo alarm unit which gives off a really nice loud beep when the battery gets low so you know to come back in to the shore.

Step 5: Sealing the Hull With Silcone Sealant

With the hull fitted up, I used some automotive black silicone sealant on every edge. I actually went over it twice as well to stop any leaks, and it also bonds the hull to the body of the duck.

Step 6: Bellows on Direction/rudder

The rudder arm has to protude through the hull so I am using some Bellows that are packed with grease to keep them sealed, and a cable tie on the end to help keep it watertight.

The transmitter throw had to be adjusted as well as the nozzle on the jet motors dont have a lot of travel and I ended up with only about 45% of the normal travel.

Step 7: Cutting the Lid

To be able to remove the battery I cut out a hatch on the top and added some tabs with plasticard, glued these solibond which is some pretty amazing glue to use. I then added a little magnet at the back as well to keep the lid shut and another magnet under the plastic tab

Not exactly waterproof, but it should stop splashing and its a low speed duck dont forget, so minimal wash

Step 8: DUCK BOM - Parts List

1. A Duck - plastic decoy (not wood)- https://ebay.to/3izbcki

2. 15mm Jet boat motor - https://ebay.to/2Ruri2U

3. TX/RX - Futaba DX6i + Lemon DSMX RX - https://ebay.to/3c0eZ7K

4. 10A Esc - https://ebay.to/3mnfltZ

5. 9g Servo - https://ebay.to/2ZEMYha

6. 2s Lipo (JST connector to fit ESC) - https://ebay.to/3c1LO49

7. LIPO Alarm - https://ebay.to/3ixalkc

8. Bellows - https://ebay.to/2FCd4dp

9. Brass rod , bent 1.6mm

10. Plasticard for lid

11. Solibond glue (500ml size) - https://bit.ly/3hyLuv5

12. ABS/PETG Hull - STL (hull outline based on a design by Darren Gossling)

13. ABS/PETG Servo mount

14. ABS/PETG Battery sled

15. ABS/PETG RX case

16. Black Silicon sealant - https://ebay.to/2FwRzen

Step 9: Bath Time

It works, it runs and has a turn of speed. There is no real reverse to speak of, but it will slowly go backwards. If you wanted real reverse then you'd need nozzle blades to divert the flow

Step 10: Down at the River

What a beautiful site as the duck glides around the lake. Take THAT Park Keeper !

Make it Move Contest 2020

Runner Up in the
Make it Move Contest 2020

1 Person Made This Project!

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89 Comments

0
big-bill3
big-bill3

5 months ago on Step 6

I’ve got it working but operating the steering bellows pumps water into the hull.
ideas?

0
Ajaxjones
Ajaxjones

Reply 5 months ago

The cable tie needs to be tight, and I think I glued it in with super glue at the other end too. Plus I packed the bellows with some old bearing grease I had lying around.

0
big-bill3
big-bill3

Reply 4 months ago

I’ve found that the bellows need to have the correct minor diameter to match the hole in the hull, otherwise there will be a leak between the bellows and the hull. I seled this leak with Gorilla glue which flows well then sets.

0
big-bill3
big-bill3

Reply 4 months ago

After all the searching for leaks in the sealant, I’ve found that there was a crack in the 3D moulding on the transom of the hull. Most annoying.

0
big-bill3
big-bill3

Reply 4 months ago

Thanks. I got that bit sealed with cable ties at both ends. Then found that I had not sealed around the nozzle properly so had to take it all apart again.! Also The sealant you recommend is better and easier to work than ordinary silicone. I hope.
The rc side of things has been wrought with irritations. The first servo I ordered was faulty as were the first two ESCs and as it’s the first time I’ve played with rc equipment I had trouble working out what was wrong.
if you’re reviewing the 3D items you might like to remove the screw holes and let the person building it drill their own to match the positions of the holes in the jet moulding. Also the screws supplied with the jet moulding were a couple of mm too short to reliably screw into the moulding so I had to order some longer ones which in the current lockdown took ages.

0
big-bill3
big-bill3

Question 7 months ago on Introduction

I would like to modify the stl file for the servo sled. As much as I have tried I cant ungroup nor edit the STL file. Please would you post a version of the file that I can edit?

servo sled.JPG
0
big-bill3
big-bill3

Answer 7 months ago

TinkerCAD tell me “Imported STLs cannot be ungrouped in Tinkercad. You might try Meshmixer to separate the shells if you need to.”

0
big-bill3
big-bill3

7 months ago

Great project for lockdown but I’m having trouble understanding how to connect the ESC etc. A circuit diagram would be good

0
Ajaxjones
Ajaxjones

Reply 7 months ago

I'll see if I can draw it up, but its exactly the same way that you would wire up a R/C car. Throttle with a Speed controller and servo for the steering

0
big-bill3
big-bill3

Question 7 months ago on Step 4

How is the servo Mount secured to the jet pump moulding?

0
Ajaxjones
Ajaxjones

Answer 7 months ago

I just glued the servo carrier to the motor

1
big-bill3
big-bill3

Question 10 months ago on Introduction

Hi, I’d love to build one of these for use on our local boating pond but I have no access to 3D printing. Any ideas on how to make the hull?

0
big-bill3
big-bill3

Answer 8 months ago

I have found someone who has printed the set for me

0
FlorinJ
FlorinJ

Answer 10 months ago

From the looks of it, it shouldn't be very complicated to replicate it in wood. If you then coat it in fiber glass cloth and epoxy, the way wooden boats are coated, it should do the job quite well. Since the load it has to carry is very low, the wood can be the thinnest marine plywood you can find.

1
colescolin
colescolin

Answer 10 months ago

I would say a plastic bottle would do the trick

1
BerenV
BerenV

Answer 10 months ago

There are quite a few online 3D printing services that can be more affordable than buying your own printer. One example I’d recommend is ShapeWays. You can send them the stl files and have them print the parts and ship them to you for a fee.

If possible, please post the editable 3D file. I need to modify the hull to be thinner.
Thanks

0
brittonholland
brittonholland

Question 10 months ago

I have a project using a jet drive and 3d printed housing. I had a lot of issues with the water coming through the print itself. What material / settings did you use?

1
Ajaxjones
Ajaxjones

Answer 10 months ago

nothing fancy with this, it was at 0.2mm and in ABS. I did have a crack for some reason that was sealed with superglue. I'm going to be doing another with screw drives and will use PETG for that