Foil Assist Build

Build, Repair & Mod
1

Hi,
I’ve been using foilzone to help build a foil assist with the intent of learning how to pump and then learning how to ride waves. I already have a lot of foil experience using a kite but pumping and waves are skills I don’t have.

My build consists of:

  1. GY1310 from Alibaba
  2. Mini FSESC
  3. Flipsky Waterproof Brushless DC 6384 Motor 140KV with folding prop
  4. Flipsky 2.4G Wireless Module Waterproof Remote VX3
  5. Slingshot 32 L high roller
  6. Evergreen 56 dry box
  7. 2x 6s 6 AH Yowoo
  8. custom heatsink from JLCPCB that protrudes from the dry box: Onshape

The last thing was my way of trying to get the ESC heat out of the dry box without reverting to liquid cooling. Essentially I remade the ESC heatsink with very long fins that extend out of the drybox and got it made out of copper($80 with shipping). It seems to work OK so far but I haven’t really been able to run it for extended periods because… of lack of skill.

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Issues:

  1. The power is marginal at full charge and then insufficient at about half battery.
  2. remote is hard to connect when first starting out because the dry box is submerged and requires some wiggling around to get a connection.

More board volume would probably help, I’m around 80 kg, and that doesn’t help.

I’m going to try to bump up the current limit on the ESC and see if that helps.

The mini ESC fits well in the box and the accessibility of the surfaces that put out heat made it work well. 50 amp continuously at 6s should be able to do much more than that 600 or so watts I’m seeing on the controller but who knows how accurate that is.

Any pointers are welcomed.

Bill

2 Likes
2

Which mini Fesc exactly it is? If it can output only 50A, it is too low. Should be at least 100A as per experience of users.

  1. Holding the remote next on the box doesn’t help?
  2. Place the antenna exactly bellow where you hold the remote.
  3. Place the box in front to be out of the water.
  4. Open the remote and put silicon around the antenna.
  5. Extend the antenna to the front. There is an antenna extension that can be glued outside.

How much this wing set cost you ? Is it carbon mast ? How much it weighs, please weigh it for me - weight per component , thanks? Does it feel stiff in the water?

3

I’m using the 50 amp mini FESC, looks like they have a 70 amp, and that might be worth upgrading to, it’s the same form factor so it would work with my heatsink.

I bumped the current limit from 60 to 75 amps. Before I was getting around 800-900 watts max, now I’m seeing 1200-1300 max. That is enough to get me on foil, before it was pretty marginal.

I was able to ride on the foil but it’s really finicky, could not stand up, was on my knees but I think I’ll get it dialed in after a few more sessions. On foil I’m showing about 750 watts. 50 amps at 45 volts(2250 watts) leaves a lot of headroom but I don’t think you can believe any of the numbers coming out of these devices. The foil is very high aspect, so it’s not surprising that the power demand would be lower.

Temps come down quickly once back in the water, but the way the heatsink is set up its in the air when I’m on the foil and I see up to 70 C which is getting close to thermal limiting. I wasn’t on foil long enough to get the temps above there. 15 seconds after going back in the water the temp is like 55 C.

It should work for what I want to do, get up on foil and learn to pump. And then boost into a wave and surf. Given how squirrelly the foil is I might have to get something different.

carbon main wing is 1494 grams
carbon tail is 140 grams
AL fuse is 810 grams
78 cm AL mast is 1658 grams

All weights are without the stainless screws. Mast might be heavier because of water intrusion.

Paid $507 with shipping and tax to the US with a spare mast. I was expecting a 70 and 90 cm but ended up getting that 78 cm and a 73 cm… might as well be the same not sure why but that’s what I got.

I haven’t laid hands on a Axis 1310 but it looks very similar. Would love to know how those weights compare to the Axis foil, and if there is an off the shelf carbon mast I can buy.

I can’t really comment on how stiff it is, just haven’t ridden it enough but it did a times feel wiggly, that could just be the prop wash.

Moving the box forward isn’t ideal, nor is holding the remote next to the box.

Where can I get the antenna extensions you’re talking about?

1 Like
4
  1. You could obviously make a hole in the box and run long antenna, but here
  2. He attaches antenna tip on top of the box and it works for him
    Foil Drive External Antenna Tutorial – FoilSurfing.Net
  3. FD assist gen1 fiddle a lot with antennas. You can join the FD owners group on FB and search there

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2 Likes
5

Thanks for the tips, I managed to get an antenna, wasn’t real clear from the video what one was recommended but this is the one I got:
https://www.amazon.com/dp/B07GNC8DHH

And I think it will work, just installed it with silicone on the deck:

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6

Antenna works great, really impressed that I didn’t need to add another penetration to the drybox, just taping the stripped coax against the outside where the surface. Was able to stand on the GY1310 and cruise at around 750 watts, it’s still really hard to ride. Thanks for the antenna tip.

7

So you are able to control the box while it is under water? The remote also under water or you hold it above?

The placement of the box way at the back - are you ok with it? Doesn’t it sink the back?

8

I am able to control the ESC when the box is submerged, but the tip has to be out of the water or I have to hold the remote directly on the external antenna. As soon as I start moving its no issue, the board is quickly out of the water.

I don’t mind the battery box being on the back the way it is. For the board I ended up with its probably the best I can do. The back of the board is completely submerged when I take off, but with the antenna hack(thanks to lishine) I’m able to get going with out having to wiggle around to get a signal, the signal good when the tip of the board is out of the water. I’m only using two batteries, so the weight on the tail is minimal. I’ve had about 5 session now and it works well, I get 30-45 minutes of playing around before its dead.

The GY-1310 is very hard to control though, I’ve been looking at the ART foil offerings on alibaba and thinking I might get something different. I’m not sure if the difficultly in riding is something I can overcome with some time or if it’s just a really hard to ride foil. It does seem like the GY-1310 is too much area for prone foiling, and that’s my goal so I’ll probably need to get something different.

I also picked up one of the 70 amp ESCs, I haven’t installed it yet, but the dimensions are identical to the 50 amp one I have so it will be a drop in if I need more power with a different foil.

here is another picture:

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To hold it down I initially had just one strap across the box. I thermoformed lexan into loops and glued them down with gflex, and they came off after a couple of big wipe outs, so I added another strap the holds the front down, and it’s stayed put after that.

I’m not a virtuoso but I can ride a foil behind a kite pretty well. Any recommendations of an Alibaba foil that’s easier to ride?

1 Like
9

If your goal is prone surfing, why do you have the motor in e-foil position?