Search found 38 matches

by srn
Apr 17, 2018 9:22 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Also, I saw that you are going for a gearbox build. That's actually the way I was going too before I noticed that at that rpm range, the gearbox is going to be really really hot. Did you already think how to cool the gears? Cheers Interesting point, have not thought about this yet. My "Gearbox" are...
by srn
Apr 17, 2018 4:51 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Hello ZR38,
Good question, at the moment I think to measure the thrust a kind of spring-scale should be the best.
by srn
Apr 16, 2018 9:48 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Hello ZR38, there is no rule because it highly depends on impeller design. I was reading many numbers between 8.000 and 15.000 rpm. For my project I ordered a powerful motor (Lehner Torqstar 3) and will test my relatively small impeller (60mm) from 0 - 17.000 rpm. Diagrams of thrust/rpm and rpm/powe...
by srn
Apr 04, 2018 1:01 pm
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

currently integrating my drive unit
E768BF48-278D-4B49-823A-1840EAEF3310.jpeg
by srn
Apr 04, 2018 1:54 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Hi srn. so my first impressions are the mgm esc is very very good indeed. i bought the industrial version, so i dont know exactly how different it is from the modeller version. it was pretty expensive at 1100 euro. but the temperature protection works great as i found out today. extremely well manu...
by srn
Mar 27, 2018 7:22 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

hello i didnt recveive the esc yet. mgm said it would take 3 weeks to complete, but it then took nearly 2 weeks just to get an order confirmed from them, ultra slow response via email. its now been 5 weeks since i started the process feeling a bit frustrated Hope that it will arrive soon. Would lik...
by srn
Mar 27, 2018 2:30 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

[..] lehner motor. looks nothing like it does in the photo. looks well engineered, its smaller than i expected, some real nice innovations in it. like each winding solders to a pcb instead of being wound to the next winding (ill take a photo so you understand what im trying to say). The thing i was...
by srn
Mar 24, 2018 7:38 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Hello, I created completely new jet. It will be availible soon for download, after I printed and testrun it. Here are some pictures. I improved bearings, added grease nipples, better waterflow.......... Hello Toto44, Your design looks good, I only wonder how you want to machine it ? 3D-Print ? Mill...
by srn
Mar 07, 2018 1:53 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

no probs, yeah post it up when done, would like to see it. i also called scorpian motors, and they gave me an offer on this https://www.scorpionsystem.com/catalog/helicopter/motors_4/hk-70/HK_7050_340/ of with water cooling, at custom 250kv of 1100 USD shipped. I think the Scorpion is a little bit ...
by srn
Mar 06, 2018 7:35 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Thanks you for this information.

MGM + Lehner would also be my first choice at the moment.

I am currently milling the drive unit foundation. Will post pictures in the next days.
by srn
Mar 06, 2018 2:55 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

no, my battery pack is rated at 160A cont. but my old motor was drawing 160A peak when full throttle on the jetdrive. i dont really expect that to change much, since im using the same size prop, and the motor will have the same number of windings Hello Chris, Any updates with the new Torqstar ? I a...
by srn
Feb 19, 2018 2:31 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

chris_kline wrote:
Feb 16, 2018 3:30 am
well looking at the alien power system 83100. that actually is the chinese motor i had.
Do you want to use same ESC for the Torqstar ?
by srn
Feb 16, 2018 4:23 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

yes they are all same ..
but you burned it, so maybe I should also go for the Lehner directly.

1000€ vs 180€ :roll:
by srn
Feb 16, 2018 3:08 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

I wanted to buy the Torqstar but was also oftentimes thinking about Alienpowersystems 83110 with 7kw.

Maybe 7kw is enough to start with ..

just dont want to buy twice.
by srn
Feb 15, 2018 12:54 pm
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

I want to use the same motor. How long do you have to wait for it ?
by srn
Feb 05, 2018 7:51 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

chris_kline wrote:
Feb 04, 2018 1:35 pm
well, it worked!

first test https://youtu.be/QXQUv2pck1Y
Hello Chris,
congratulations, it looks really good.
But be honest, I think you increased the video speed ? The waves are moving fast .. :wink:
Anyways it is visible that the board is driving fast and has good gliding ability.
by srn
Feb 02, 2018 2:33 pm
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Frizzo wrote:
Jan 31, 2018 2:57 pm
Well, let's hope for the best!

It also seems to me that your jet unit is kinda going underwater. Doesn't that lead to thrust losses?

Cheers
I think the same.
by srn
Jan 09, 2018 3:17 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

My jet unit is making progress
by srn
Jan 05, 2018 5:20 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

Did you think about something like this ?
https://hobbyking.com/en_us/turnigy-nan ... -xt90.html

with a 2s3p setup you will have more power, less price, less weight and less work compared to 114pcs of small batteries.

just 300$ compared to 725$
by srn
Dec 13, 2017 1:52 pm
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

chris_kline wrote:
Dec 13, 2017 11:31 am
here you go. i just put a nut in the mould prior to injecting epoxy
Our shape is nearly the same, but I think I will mill a new mould with same system of screw & nut.
Have not thought about this before, very good idea
by srn
Dec 13, 2017 8:15 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

chris_kline wrote:
Dec 13, 2017 7:17 am
Finished prop!
great work,
how did you make the screw thread ? Is this ready-to-buy part that you glued in ?
by srn
Dec 11, 2017 3:45 pm
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

thanks

out of curiosity, what pitch did you put on your blades? looks good, im just curious if we ended up around the same ballpark figure
My pitch is 57mm, diameter 60mm.
by srn
Dec 11, 2017 2:19 pm
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

chris_kline wrote:
Dec 11, 2017 12:51 pm
heres some pics of my mould, and the prop that came out of it before cleaning it up. pretty much the same thing as srn did with his pe mould.
looks very good
by srn
Dec 06, 2017 11:01 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

I used PE because Epoxid Resin should not stick to it.

But because of a too rough surface, it is sticking like hell ..

For my second Impeller, I applied normal candle wax on the surface.
This worked very well.
by srn
Dec 05, 2017 12:44 am
Forum: Electric Watercraft
Topic: Electric Surf Board
Replies: 575
Views: 115921

Re: Electric Surf Board

ropower86 wrote:
Dec 04, 2017 7:18 pm
srn wrote:
Dec 04, 2017 3:31 pm
here my mould out of PE.
How many impellers have you made out of the PE's negative mold?
At the moment two. The second one has already the quality that I want for my prototype.