Hi all, new here.

Hi all, new here. I’ve been working on an 3D printed jetsprint boat, just thought I’d post some pictures here of what I’ve been working on.

This is iteration 2 in the making, version 1 goes quiet well! Version 2 will have a inrunner motor (rather than the borrowed low KV one in there atm) and reverse bucket too so should be fun to play with. The impeller holds up surprisingly well printed in 2 perimeters in PLA. I’m quiet happy with it!

If there is interest, I’ll post the files somewhere : )

UPDATE:

Files inc solidworks source files: https://www.youmagine.com/designs/prototype-jetsprint-jet-boat

RCgroups thread: https://www.rcgroups.com/forums/showthread.php?3061106-Thrilled-to-discover-this-subforum-been-working-by-myself!-3D-printed-jetsprint

That impeller and housing are VERY, VERY nicely done. Looks fantastic.

Thanks! I got a giant 3670 motor for it in the mail. When I do release it I’ll add a few more adapter plates for other motor sizes. Maybe I can even add some multicolor printer features. Who knows maybe we could even get it added to the OpenRC collection?

I do not see why it wouldnt be added to the collection. What is the drive shaft made of? Will a larger motor than a 3670 not snap it?

I’ve just been using a 3mm steel shaft and running it through a 4x3x10mm bearing. 3670 motor is overkill I think. I expect the PLA impeller to fail first.

1100kv on 3s is a little slow. 1900kv should help with the potential to go 6s by putting the batteries in series for experimenting mainly. I’ll find out what rpm range works best. I can measure the current and work out rough efficiency.

Neat! Hope to watch the video of the prototype soon. Good luck!

I am very interested in this project. I have been waiting for a boat to be released for quite some time. I live on a lake so it’s easier to use boats on the water in comparison to RC cars, drones, planes, helos, etc.

I’m just trying to decide on a scale for it. At the moment it prints nicely in 2 parts that are 195mm tall each.

Dual Jet, Dual 1900kv motors, 6s in parallel and 100cm in length. Please.

@Mathew_D3lap it wouldn’t be a proper jetsprint then I’d probably want a different hull shape regarding intakes mmm… That would be one hell of a RC boat. This one will be 430 mm long… I’ll start with that. Later versions maybe close to that 1m length :wink:
I’m definitely not against making more boats and making them big and fast :smiley:

Doing some reading into ideal rpm for jetboat pumps it seem that the most efficient range somewhere between 20k and 30k rpm. It appears beyond that more RPM doesn’t actually increase speed. I’ve got that 1900kv motor coming that I can do at 6s so I can test if this is accurate. 120A esc, motor rated for 66amps… this is gonna be good.

More power = More speed any motor head knows this. I wouldnt even be able to print anything over 240mm Long. So it would have to be sectioned off.

I would be careful with cavitation. Only so much water can be sucked through the intake. If you are expelling more then you are taking in you will start cavitating. When you cavitate is when you break props, shafts, etc. This is coming from experience with standard nitro, gas, and electric boats.
I would be willing to be a beta tester for you on any designs.

@Will_Nelson thanks Will. Good to have someone on board who has experience in this area.

@Will_Nelson would you happen to know anything about jet pump optimization?

Atm the duct is 30mm the impellor is 29mm and the nozzle narrows down to 18mm. I’m just borrowing proportions from another jet but any pointers would be great if anyone has any. It works great as is though I guess it could always be a little better :slight_smile:

@Jotham_B Not really. Thats the study of fluid dynamics. Not my area lol.

https://cairnindia.com/sites/default/files/2013_SPE%20Large%20Scale%20Jet%20Pump%20Performance%20Optimization%20in%20a%20Viscous%20Oil%20Field.pdf

Man, those renders are so pretty. I really need to start learning fusion360.

Just need to get the reverse bucket setup, the lid fixed and it should be good to go!

The pipe takes in water to the motor just behind the impeller on the side just before it starts to narrow down the flow.

The idea with the motor bracket is that if anyone has different motors laying about its simply a matter of making a bracket to fit it in. I might just do that too with the servo mount. For the steering pushrod I’ve just got a small hole made - it works just fine on the prototype so I don’t think a rubber boot to seal it will be required. Anything else I have missed? I usually just velcro my batteries down. The plan is to have a 2200mAh on either side of the motor to keep it balanced. In future versions I’d like to have a single battery since I’m not sure if everyone has two identical motors for each side. It’d help keep the cost down for new builders. All feed back is appreciated. Thanks :slight_smile: