I used a Dermal
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You're welcome, I practiced on on some scrap wood.
Just make sure you have a firm grip on it. In my practice runs it got away from me few times.
Hi all
Its been a while. My flex shafts finally arrived aftre a lengthy delay at our post office....
Does any one know what a good C.O.G. starting point would be on my boat?
Thanks.
I’m still playing with mine but 30% is a good point to start. I have it written down and I’ll get the measurements for you in a few hours when I’m alive, lol
Thanks
Got the first flex shaft installed
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Great Brad, you are sooo close. Do you have clear water where you are?
Brad I have 13 3/4” of the wetted surface for CG written down. This is with a 17lb RTR weight.
Thanks, I do. There is a good size dam around an hours drive from where I live. There is also a small dam 2 minutes from my house so that's where my first run will be.
Hmmm, please bare in mine that this is my first boat so I have absolutely no idea what the wetted part is. Please will you put that into "boat building for dummy's" terms.
Thanks bud.
Thank Shawn, much appreciated.
COG, depends on speed goals. If this is a triple digit speed boat, you could be as high as 40%. Lipo sleds will usually provide quite a bit of balance point adjustment with heavy batteries.
Last edited by fweasel; 01-09-2019 at 05:20 PM.
Vac-U-Tug Jr (13mph)
Ok cool, thanks Ryan.
Made some good progress today :-)
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Too late now, but the white epoxy you used to reinforce the water pickups could have been dyed black to blend it with the rest of the interior. I have not tried it myself, but I know kfxguy has dyed fast setting epoxy (5min or 30min) and used that almost like paint to recover and blackout epoxied joints for purely aesthetic reasons. Your ESC's look nice and neat with that mount, even better once the beauty panel goes over the top. Still messing around with how I'm going to mount mine. Haven't ruled out mounting them to the side of the hull either.
Vac-U-Tug Jr (13mph)
Thanks Ryan
Fortunately the white stuff on the water pickups is " Prestik". A removable putty. I like the idea of the dyed epoxy, thank that's what I'll do as the permanent solution.
I need some advice on my next few steps please.
1) This is my first twin motor setup, do I use a Y connector and remove one of the positive wires from one ESC?
2) Is there any preparation that needs to be done to the end of the flex shaft before it is clamped into the collet?
3) What grease should I use on the flexshaft?
Thanks in advance.
Definitely de-pin one of the red wires on a single ESC plug, then use a Y-plug. Don't cut the wire. Assuming they both have a BEC, you'll need that pin back in place when you set up the ESC by itself for the first time.
If I have to cut my flex cables to length, I put a slight bevel on the tip with a bench grinder. I've never found it necessary to solder the ends, but have run some like that because they came that way. I also like to polish the flex cable with some 600 or 800 grit sand paper while the propshaft is chucked in a cordless drill. I run the cable through the sandpaper while I pinch it between my fingers.
I've been using just plain Proboat grease on my cables and wires. Some people use regular marine grease, others gear oil or cocktails of the two mixed together. I've been meaning to try a mixture myself on some of my drier boats that don't need as much grease to keep the water out of the tubes in hopes of creating less friction on the spinning cable.
Vac-U-Tug Jr (13mph)
Thanks Ryan
Appreciate all the help.
Ryan I’m going to add to your advice here.
1) if you pull the + wire out of one side of the Y harness and keep the ESC wire intact it will be better for programming at a later date.
2) don’t polish the tip of the flex cable which goes into the collet. I have found that I have HAD to solder to get a snug fit of the cable into the collet. The diameter of cable seems to vary at times.
3) yup, just blue Marine grease(Proboat,Lucas) as it’s all pretty much the same. I will then drip a few drops of Duralube down the flex where the flex goes into the stuffing tube. It’s my habit to do the night before my 100+ runs.
And I don’t generally change out my flexes after every run. The oil helps with that I have found.
But it certainly depends on how much contamination from water occurs.
Ok that’s my 2 cents
Thanks Shawn
Won't be long now and she'll on the water.
1) Good tip. Not sure why that hadn't occurred to me before. Probably because that's what I did on single ESC's when I added an external BEC for higher servo voltages.
2) Exactly, sorry I didn't mention that. I actually put masking tape over that portion of the flex to server as a visual reminder of where to stop while it's spinning in the drill.
Vac-U-Tug Jr (13mph)
Awesome build !! Can’t wait to see how it runs!! I jus picked up the tp 4050 cm 2300kv motors for my cat. Going to try them out tomorrow and see how she does
Awesome, please let me know how she runs.
It ran well was able to get 98mph out of the tp motors. Will go back in a couple of weeks with some different props and see if I can get 100mph.
Well done, 100 mph is just around the corner.
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