Whiplash P Sport Hydro Build

[Shooter]

Wow Jimmy. Nice work on all of this! It's about time!!!!

[tjcast]

Coupler187.jpg Here's a nice coupler

[jfrancisco892]

Thanks pete!

Tom what brand of coupler is that?

[tjcast]

That is a TFL one. I've run them for 2 years.

[b0atnutz3]

Jimmy you might want to put that turn fin on the inside of the bracket it will not flex as much as it will have the bracket backing it up. You can try to flex it as is and then switch it to the inside and do the same pull on it at the very bottom of fin bet it flexs more the way it is than it does mounted inside. Just my opinon not saying it won't work but have been down the turn fin road a couple of times testing and testing some more. Jerry

[jfrancisco892]

Just as a quick update as I mentioned the octura coupler was running out and I was gonna have my dad machine it out and put a bushing in it to fix the problem but it was a hardened steel and was not machineable. He tried to anneal it but unfortunately it distorted the flex cable side of the coupler. Anyway he determined it had .015 T.I.R. so I wasn't gonna use it anyway as I could visibly see the runout when spinning the driveline. I am going to try the MBP collet clutch and see if it works any better. It looks like a well designed and machined unit and it addresses the issue of the set screws cocking the coupler onto the motor shaft by clamping itself onto the motor shaft instead. I'll let you know how it works and what I think of it.

[detox]

Sometimes you can reduce runout by tightening the collet in steps. First step just lightly tighten, next rotate collet 180 degrees then tighten again, rotate another 180 degrees then tighten again. Do this until collet is tight enough so that no slip occurs.

I use a very light coat of Never Seize on interior wall of collet nut (threads and taper)

[jfrancisco892]

The issue is caused from the slop between the motor shaft and the id of the collet on the motor shaft side. Interesting idea though. Thanks

[flraptor07]

THAT is exactly why, I won't be using Teflon in any of my new builds.

Later,
Mike

Deffinetly! If you grease your flex after every time out like you should, then there is no need at all for teflon liner. You won't see any of my boats with a liner. And I've asked almost everybody in the club I'm in and 90% don't use liners anymore

[Shooter]

The issue is caused from the slop between the motor shaft and the id of the collet on the motor shaft side. Interesting idea though. Thanks

Ouch! I better check my collets for this. Probably can't avoid having at least a little clearance to slip it over the motor shaft. However, if it's excessive, it's no doubt going to run out on you and cause vibration, etc... Good catch.

[ray schrauwen]

I find many Chinese collets are very tight on the shaft BUT, the bore is fairly rough on some. How true they are is to be seen, some good, some were not.

[jfrancisco892]

Had the maiden run this weekend and overall it went pretty well. I started out with the 42x66 and it had a considerable amount of hopping in the back of the boat. A club member advised me that running a larger diameter propeller might alleviate the problem so I went to the Grim 45x68 which is supposed to be equivalent to the ABC H-5. It ran a little better with that prop but was still hopping. Then I decided to try the H-7 and the hopping got slightly worse. That was all I got on the first set of packs, so I threw in my 2nd set of batteries and re-greased the stuffing tube. From what I noticed it, the .187 cable and .250 brass tube with no teflon line is noisy if not greased thoroughly after every run. Anyway, I kept the strut depth the same but gave it some positive angle (prop pointing towards the sky) and this made the hopping worse. After that I put some negative angle on the strut (prop pointing toward the ground) and this helped quite a bit. It was running decently by the end of the day but still had a slight bit of hop in the back of the boat. I'll probably put about half a degree more of negative angle on the strut to fix that problem and fine tune from there. I'll probably stick with the H-7 for the first race as it seems like a good fit for this boat. I did check the data logging from the esc and the average amperage was right around 150. Maybe room for more prop? The turn fin worked like a charm as even though the boat was not perfectly planted on the water on my last run I had no problem holding it wide open around the corners. Hopefully it will have a good first outing this weekend at the first club race of the year. I'll see if I can get some videos from the race this coming weekend and post them up.

[Fluid]

All the props you used are lifting props, they will be more likely to cause hopping. Moving thr CG aft will help reduce the hopping, as will using low lift props like Octura x props.

Pulling 150 amps average is not bad for a Castle 1515/1Y, can't find the exact motor you are using. Actually, running the strut with a down angle at the prop end increases hopping as it lifts the transom. Can't explain why you see the opposite. Adding a bit of cup to the tips might reduce hopping, but a CG change is probably the best solution. Raising the strut a bit might also help.



.

[ray schrauwen]

You could try a D/T & back cut x642. Works well for some running a 1515 1Y.

[detox]

All the props you used are lifting props, they will be more likely to cause hopping. Moving thr CG aft will help reduce the hopping, as will using low lift props like Octura x props.

Pulling 150 amps average is not bad for a Castle 1515/1Y, can't find the exact motor you are using. Actually, running the strut with a down angle at the prop end increases hopping as it lifts the transom. Can't explain why you see the opposite. Adding a bit of cup to the tips might reduce hopping, but a CG change is probably the best solution. Raising the strut a bit might also help.



.

I agree with Fluid.

The m445 with a little cup added to tips will get that boat going well (2200 kv?). I bet you are running too wet on the front sponsons also....move COG farther back toward stern. Start out with 1/2" strut depth to prevent running too wet. If too loose (flyovers) try deeper 5/8" depth using setup board (adjust strut level with board). Strut Depth is measured from bottom edge of stern to bottom of strut resting on board.

Boat should plane smoothly on smooth water without bouncing on sponsons or stern (test, test, test). An good experienced hydro guy can get that boat going fast.