Electric Surf Board

[Quinc]

That 3d printed pump is awesome!! Great project. You might also look into the older and currenty powered surf boards.

 

[toto44]

Thanks,

meanwhile I reworked the pump, and will do some testing. Also I am trying to get a used surfboard.

I will post pictures soon.

 

[bbq870]

how did you construct/design the pump?
based on an existing model, just guessing or even on hydrodynamic optimized shapes?

pls post more pics!

 

[toto44]

http://www.rc-raceboats.de/forum/showthread.php?39445-Teile-f%FCr-Jetantrieb

I have some parts for sale.

Pics of the new unit soon.

 

[Animalector]

Can't see without logging in

 

[toto44]

These parts are for sale

Alltogether 55€

 

[fer344]

any tutorial or suggestion? all people here are cracks? :lol:

 

[FROGMANGEEK]

Hi every one,

I am new to this forum, but I m watching this thread for weeks now.

I am working on a outboard ejetpump for my longboard.

I would like to reach mimimum speed to stand up on the board and turn. I ve already made toto's jet pump.

Toto do you leave the projet , I see you are selling your prototypes? DO you have an idea how much RPM the pump you design have the more efficient trust/speed ?

At the beginning of this post , we saw matias with his 70MM propeller ,50V , 50A jet. He wound his motor 200kv. The unit was able to reach 1000 RPM, and as he said it was too low power.
Then Ratking talk : I know that most of the stand up jet skis using 701-750 ccm motors have rpm limit around 7500 rpm.
Thats why someone have to link a few of the 80-100 180kv motors togheter and try combined with hv160. That gives 8500 unloaded. That's perfect for a ice replacement.

When I search on the web for graupner and other jet unit I see about 20-25000 rpm

I have to buy a motor and ESC for my unit, and don t want to do the wrong choice, how many RPM must I have in mind to choose my motor for this 60mm propeller jet unit?

Toto, could you tell me more about the pitch of the propeller you desgn, the first propeller and the second one?

I think I need about 2500-3000W , but I need to find the right RPM in order to choose a motor.

Cheers,

 

[toto44]

Hello,

basically, the higher the rpm the better.

Motor KV depends on how much voltage you battery has. Right now I am using a 4074 innerrunner. Expected prop speed is around 18.000/min. It will be in the 2500 Watts area. I do not know if the printed prop will be able to transfer that amount of power, especially as I plan to go to 4500 Wats later. My plan was to find the right geometry for the prop and then machine it from Al.

Best regards
Toto

 

[FROGMANGEEK]

Okay I understand all better now ! Thank you.
Regards,

Envoyé de mon D6503 en utilisant Tapatalk

 

[FROGMANGEEK]

I am going to go for 3d printed one. I will tell you if the propeller do the job with 2000w

Envoyé de mon D6503 en utilisant Tapatalk

 

[Hillhater]

Hello,
basically, the higher the rpm the better.......
.....Expected prop speed is around 18.000/min. It will be in the 2500 Watts area....
Toto

.? sorry, but unless you have some evidence to back that up, i will say its very wrong.
It may be true for surface props etc but jet pump IMPELLERS work very differently.
I dont know of any that run much above 8krpm , and most are designed to operate in the 4-6 krpm range.
Impeller shape and design is very different to open prop design with particular attention paid to minimising the radial clearance to the jet housing and avoiding cavitation.
Any minor imperfection in the impeller or housing will cause cavitation anf huge loss of thrust
Thrust limitation is very much proportional to pump/impeller diameter much more than rpm
Let us know how you get on with that 2500W @ 18krpm !

 

[toto44]

Maybe you are talking about the fullsize impellers?
These smaller unit need higher rpm.
Check the ones availible:

http://www.mhz-powerboats.com/Jet/Jet-Power-924.html

Toto

 

[sonico]

Hi All, this is my first try, only to roughly assess the thrust obtainable: https://www.youtube.com/watch?v=Ss3Ywsg45f4&feature=youtu.be
The motor is an Align 700, batteries are 3.3Ah 45C 10s, ESC is a YEP 120A HV, jet is a JET-Antrieb 5 from Graupner (49mm impeller).
At full throttle, the current clump measured 68.5A.
I could not measure exactly the trust because I broke the scale , I'll have to repeat the test with a new one.

Now my problem is how to mount the thruster in the board...

 

[dirkdiggler]

I saw this while checking out the link. Graupner had an Esurfboard jet they advertise. Likely the exact one Lampuga uses.

http://www.mhz-powerboats.com/Jet/Jet-62.html

 

[toto44]

I reworked the jet. The main housing is one part now and printer friendly. The diffusor and nozzle are one part now, and I added a steering nozzle. All this is currently build into a large model boat fuselage, to testrun it. If the results are good, I will start cuttung my surfboard

 

[FROGMANGEEK]

https://youtu.be/_sYcFSJBAqg
First test of the jet turbine I made with Toto s template. This is the first version, I didn t try the new propeller.
Only 500w on this vidéo, I need bigger motor.

Envoyé de mon D6503 en utilisant Tapatalk

 

[sebkitesurf2]

Hello,
I introduce myself , my name is Sebastien , I'm French (sorry for my bad english ), I proposed to make a hydrofoil with electric propulsion as in this video
https://www.youtube.com/watch?v=T82c88iKCXU
or this short one
https://www.youtube.com/watch?v=krj41kXDlYs
what is interesting with hydrofoil is that no one needs too much power to fly, but the problem is that the part under water should be very good profile
I would like to reach a minimum speed of 20 km / h on water to start to fly and then as there is no resistance with the board the speed will increase smoothly

I need your help to choose the material for the manufacture
firstly I have never had any problem to make the measurement on board as well as hydrofoil ( i manufactures regularly)

My problem is the choice of motor, controller , battery and jet drive
For the engine I would like one with a maximum diameter of 60mm and maximum power of course
Battery .... depend the engine power i think ?
Controller... ?
And for the jet drive, maybe by a Graupner but which model ...?
If you could give me an idea equipment to buy and some good places where to by that would be cool
Thanks
Seb

 

[FROGMANGEEK]

Nice idea. I dont know if kai leny use propeller or water jet unit.
Do u know how to design foil for a board, wich material we need?
What airfoil profile ?
You should use this kind of waterjet:
http://www.mhz-powerboats.com/Jet/Jet-62.html


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[vladsbeat]

Hi Guys.
Just getting all the components in a spreadsheet.
Got stuck with the hull. Any ideas if someone custom makes hulls for these purposes or maybe any cheap reuse of a windsurfing hull?
Cheers.

 

[sebkitesurf2]

Nice idea. I dont know if kai leny use propeller or water jet unit.
Do u know how to design foil for a board, wich material we need?
What airfoil profile ?
You should use this kind of waterjet:
http://www.mhz-powerboats.com/Jet/Jet-62.html


Envoyé de mon D6503 en utilisant Tapatalk

Hi , to make my hydrofoil I have already molds and i uses carbon fiber and epoxy resin , while the profile used already works.
I ask myself if the waterjet will be powerful enough ?
Maybe it would be better to start with a Torqeedo motor style like Bazaki with a gearbox ? but I did not know the power that I will need , you have an idea?
One last question, what you use as an accelerator ?
Bye
Seb

 

[sonico]

sebkitesurf2:

I ask myself if the waterjet will be powerful enough ?

I don't think you need much power: https://www.youtube.com/watch?v=jh_RhkejWLw

1 HP = 746 Watts and, considering the efficiency loss, I think a 3000W motor/ESC/battery system does the job.

I'm developing a wireless accelerator with a couple of BlueTooth LE modules, I keep you informed.

By the way, I'm interested in how you built your hydrofoil, have you a link to the project?

 

[sebkitesurf2]

Hello,
I'll try anyway with a jet pump and a motor for RC boat with minimum 6000w to be sure with a minimum of power
the foils (for kiteboarding ) are manufactured with several pieces
mat : I will make the hollow to pass the connection to the ESC and battery
the fuselage : the front is of origin but the back to bear the jetpump , and motor.
The front wing and stabilizer are of origin


for the manufacture of a hydrofoil there is a forum (in French) very boring with lots of building DIY
here is the link
http://kitefoil.forumactif.org/t1163-nouveau-joujou-made-in-hautes-alpes
I 'm curious to see your accelerator wireless, for now the only thing I have found is an accelerator for a finger electric bike but not waterproof
http://fr.aliexpress.com/item/BaFang-Ebike-Thumb-Speed-Throttle-BBS01-BBS02-BBSHD-1000W-BAFANG-Part-Accessories/32606663597.html
instal with a handle like on a bike

 

[Bazaki]

Those thumb throttle work perfectly under water I can say. Still be carefully

 

[toto44]

Hello Sebastien,

nice work on your underwater wings! Maybe we can develope something together? Do you have any drawings or 3d of the fuse, so I can try to incorporate my jet drive into it?

Have a nice day

Toto