S&B x642 running same as stock prop!? whats the deal here?

[BHChieftain]

The difference between the stock prop and the x642 on the Impulse is worth about 5+mph. On the stock prop properly setup on 4S should be able to run mid-high 30's on x642 should get into low-mid 40's. The M445, which has less pitch than the x642 typically runs faster-- it is not all about the calculated pitch difference. But I don't like the M445 on the mono as the larger diameter can cause the boat to chine walk and I think the boat handles better with the x642.
Chief

[Luck as a Constant]

S&B x642 running same as stock prop!? whats the deal here?

That's odd, even a prop change without changing setup should have yielded higher speed at least, even if not to potential , no?

Sent from my iPhone using Tapatalk

[lenny]

Not if it is running wet,
Just the temps on the setup and connectors and cells would go up instead.

Hey sillycon if and when you get the boat running trimmed out,
Post some video's so we can see how it is riding on the water.

[Luck as a Constant]

S&B x642 running same as stock prop!? whats the deal here?

Oh I see


Sent from my iPhone using Tapatalk

[Luck as a Constant]

S&B x642 running same as stock prop!? whats the deal here?

Well, in my time swapping props that were different values, without changing anything else, has always shown at least small changes in speeds, whether it be faster or slower.


Sent from my iPhone using Tapatalk

[sillycon]

I'm thinking the problem is that the boat is running really wet and isn't getting up on plane like it should; it seems like (lengthwise) there's always half of the hull or so in contact with the water. However, from watching videos over the weekend, it seems like there should be maybe only 15-20% touching the water.

I also saw one of Darins posts which mentioned that strut height should be measured from base of the keel to the centerline of the prop; I've been measuring to the bottom of the strut so I'm probably running closer to .320" strut height.

I'm going to do a once-over on the boat again this week, reset the trim tabs to 0 and move the strut down further then I'll try again.

Thanks for all the input guys. It definitely helps take the frustration out of it when I'm not trying to sort this all out on my own.

[sillycon]

So, I went back over everything on the boat tonight and in doing so, I measured the x642 I received (I also took it off the flex shaft and confirmed that it is marked "Octura X642"). From tip to tip, the diameter is ~40.50mm. Is this correct? Would shaving and balancing typically remove 1.5mm of diameter?

IMAG0507.jpg

[Luck as a Constant]

Yes


Sent from my iPhone using Tapatalk

[sillycon]

Went back out today and gave it another whirl. Ended up seeing 35.2mph on 4s which makes for a decent improvement!

Boat was riding *MUCH* higher in the water today; at a few points there was nearly no hull touching the water surface as opposed to no less than half the hull previously!

Trim tabs are 0 on the right, .5* on the left, strut is as low as it can go (there's just a hair of clearance between the hull and the flex tube), prop is neutral. CG was probably on the order of 7" or so today. The 2s batteries I have just aren't heavy enough to balance the boat further forward, and I haven't looked into a ballast solution yet.

The boat was much less consistent tonight, however, with regards to porpoising. Sometimes it would ride flat, other times it would have a bit of a bounce.

I only had one pair of batteries charged, so I didn't have opportunity to test.

I tried shooting video, but the boat is pulling pretty hard to the right so video taping with one hand while running the boat with the other made things... tricky. I'll check the footage I have later and see if there's anything of value to post.

Thanks everyone!

[lenny]

Port side trim tab down from level to 1/32 to 1/16 may help with the porpoising,
I am not sure what you are seeing as far as that go's.

If it pulling to the starboard side hard,
That sounds like you are getting prop walk.
Post some pictures of setup with the 2s cells in place,
And also some pictures of the hardware setting.

On taking the video's,
This is what I do with my cam and velcro straps I made up.
But I do not look at the cams screen at all.
camcorder 001.jpgcamcorder 003.jpgcamcorder 002.jpgcamcorder 004.jpg

Just line the cam up with the tx and aim the tx like a side arm gun,
It works pretty good when you get the hang of it.
This is how just about all my video's are taken by me.

[sillycon]

Your camera setup is slick. I, however, don't have a camera anywhere close to that size.

I forgot to mention temps; batteries 104, motor 114, esc 89, ESC/motor connectors 115, EC3 battery connectors 125.

The video I got tonight is near useless. There's about 2-3 seconds of the boat doing a pass, and the rest of it is sky/ground/sky/ground while I try to avoid a head-on into the shoreline. I'll see if I can get the wife or someone else to run a camera tomorrow or over the weekend (didn't bother to charge batteries tonight; oops!).

[lenny]

This is the first camera setup I was using, FC Daytona 012.jpgFC Daytona 013.jpg
Than I stepped up to the one above camcorder and setup.

Also,
Some member I have seen make a platform coming off the side of the tx to hold the camcorder.
image.jpgboat pic's 019.jpgboat pic's 017.jpg

[tlandauer]

.....

Just line the cam up with the tx and aim the tx like a side arm gun,It works pretty good when you get the hang of it.This is how just about all my video's are taken by me.

From personal experience, it is much easier to aim and shoot a gun than aim that camcorder on the boat. lol...
Lenny, Like that set up!

[lenny]

Hey Tim is that with a custom blunderbuss ?
You just need to get one of those custom blunderbuss dragon camcorders,
With a very wide spread lens for when your driving the boat.

[tlandauer]

Hey Tim is that with a custom blunderbuss ?
You just need to get one of those custom blunderbuss dragon camcorder,
With a very wide spread lens for when your driving the boat.