Very slow build from France


#61

About the volume, how about just strapping a big piece of insulation foam onto the bottom? Would give you more buoyancy. Will probably look ugly.

Which circuit breaker are you using?


#62

Quality one not plastic but “Bakélite”
200a put between 2x4s
Put the load on the - going to the second pack

which insulation foam to use, which can stay in water for 1H without too much absorption:
polyester expansé
polyester extrudé
polyurethane


#63

@Alexandre

The swan attack was quite funny. Spring season, maybe some swan babies hiding somewhere…

Water in the pod… Your 3D prints are in PLA right ? I think Pacificmeister experienced the same issue and he epoxied it to make it more waterproof. I would go for PETG, since layers stick much more to each other.

Do you estimate that when adding a duct, those 8S will still be enough ?

Do you think you could upload the third 3D printed part (the small cylinder) or send it to me ? I could then try to print the 3 pieces in PETG and send it to you if you want (for free of course).


#64

This part ?

All parts made off sls with grease front and back , i will add a groove for o-ring


#65

Yes. You already kindly uploaded the mast clamp front and back parts, but not the above part if I am not mistaking.


#66

i think this is it:


#67

Great.

Here you go @Alexandre, fresh from the printer. in PETG in 2 hours at 0.3 for thicker and less numerous layers.

30 per cent honeycomb infill


#68

well i know there is not much space for the 4 screws the gearbox is 47mm , it is short to fit it in 50mm tubing and not room for o-ring, i may re design it in 2 parts and had o-ring next time


#69

By looking at that part I think you can still dig in 1 mm around right before the larger diameter to have the O-ring to sit in.

I will print another one like that and mail it along to you.


#70

thank you , in that case wait, i will design a new part, i would like to use 2mm o-rings


#71

With a 2mm o-ring


#72

so the software from hifei may not be accurate for the current, my log shows:

i found this test:

the temp is ok , rpm also, the voltage is off by +4v on mine, next test as soon as possible with a wattmeter to scale the current log …


#73

got new bearing new propeller and made a new shaft (took me 3min this time) , i service the gearbox, clean everything, i glue the first time with loctite 243 blue the shaft and the gearbox holder to the gearbox, i lost the propeller after 1 hour, and it was pretty hard to take of the gearbox holder to the motor

the time i tried loctite 648 the same i use to glue the pignon to the shaft, this thing glue really hard and really fast, you have time to screw the shaft (20mm) but you have to do it very fast and never stop!!!

planing to foil , every evening before sunset this week depending on weather and water flow on the river :heart_eyes:

will see , i would like to stand up, i give myseft 3-4h of practice on this board before i build one , for the moment i am keeping the same set up, will see if i get water inside ( made new parts but i waiting to get printed) , i did order a new motor a 860kv … for the ducted version


#74

Sorry alone this evening afterwork so no video but after 1h of pratice i am up ! Not for long maybe 100m … And up again
Having a hard time to know how high i am , propeller off water a few time
I love to make turns and it seems easier to ride in circle
sometimes just before take off the board move sideways left and right very fast , why?

i did about 1H30 at the end of the first pack i put a wattmetter to check current: i got 111A, after i put a new 8S 32A and got this for the last 15min of ride:

so the data are correct from the esc, this is 3times/sec, it shows pics not record with a wattmeter, most of the times when changing rpm, start, take of…

i use multistar 4S 16A x 4 , they get a little hot and swell, i took then down 3,6V by then i wasn’t able to foil and they got pretty hot

for me the multistar can take 3C max (constant) and don’t go below 3,8v

esc… pod… cold, but the plug xt90 got very hot!

this is : slow start at 60%, standing up then 100%, goes up, too much , let go a bit and foil for 17s


#75

Nice graphs! I dont like the Multistar batteries…they just can’t handle decent current.


#76

getting ready for tomorrow :slight_smile:

the multistar 4s 16A, got down from 3.6V hot to 3.3V cold , i am charging them one by one slowly, i got 1.5 mohm cell impedance, which i think is good, no ?

my understanding of the C rating (tell me if i am wrong):
i have 8s 32A at 10c , i am using, let’s say 100A, so i will need to stop at 10A on the pack(?), so about 30% , so around 3.77V it should be find, i already notice that below 3.8V they get pretty warm

by the way i am pleased with the isdt T6 charger, working at 93% , you can push it to 25A if you have the power supply (2X20a 13.8V tested), it just doesn’t balance cell very nicely some goes over 4.2V so just i selected the end at 4.18V

so i guess you choose for the lipo to be safe on the power side: 32A multistar 10C or 14A tattu 25c :thinking:


#77

I use 2x20A 6s or 4x16A 6s, in series to run on 12s. Multistar. They work just fine, never gone below 3.6, wet one of them already… it seems to me that on 32A motor has more juice and you can feel it at high speed. Max current with my setup: 80A. If you end the course with some full throttle burst, batteries get warm. Maybe 40/45 C degrees, you can keep them in hands with no discomfort


#78

before and after, resolder every things and put xt150, missing some as150 for the lipo, le xt90 hold nicely but they were getting to hot


#79

Getting better :slight_smile:

Against wind and current


#80

went for a ride this evening, i work 5min form this spot i live 30 min away (i guess i will do that for the next 20 years…)

well that is the first time i really took pleasure riding, went for 2 x 20min, easy foilling, lot a wind but i was suprised did not matter to much, skill improve very fast, a lot more “relax” on the board even after a week of work, the only thing that still hurting is my feet, (muscle pain)

sorry not pics (alone) i went to try my “new” solas propeller, well cutting the tongue area work for sure, a lot less thrust on start , but the foilling was easy, a lot more smooth with throttle

things that went not well:

  • thrust bearing out , i probably tight the propeller to much, the bearing went out lost some balls and motor stall in the middle, try many times to start again but did not want too, i was "swiming’ back when i tried a very slow start and i worked again with some noise, i pushed it for 15’ more min

so the solas plastic propeller gives way to much thrust, at least for 3000rpm and about 20km/h, modding it worked fine, it will be nice to try to cut it just in diameter …

I don’t know why foiling was a lot easier yet, improved skills? more rpm with the modded propeller because my usb data cable let me down, so number are in the esc, i will try to solder the wire but sorry no numbers …

my thinking about this solas plastic propeller:

it is very nice, it works , gives a lot may be to much thrust, you will loose rpm between 20-30% depending on your set up 56 or 40mm motor with gear, it requises at least 3000 rpm to have fun , i think it will be hard to get some speed above 30km/h without to many amp… but it’s cheap and work fine with a geared set up, probally to big for direct drive set up that would last in time