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[Gaci4]

Cheers Martin good tip I like it  been looking at that wet well idea and came across small rubber boots , like the ones on ball joints etc on a car.

[pompebled]

Hi Grant,

If you studied the links regarding the shape and use of a wet well/flooded tube, you will have seen/read the section closest to the motor can be smaller in Ø than the hole in the transom.

If to make your wet well out of wood, it's very easy to incorporate the bottom of the hull as the lower part add two sides that start the size of the stuffing tube (or just a little larger) and flare out towards the transom, but only in height, not in width, a kind of flattened trumpet so to speak.
If I don't make sense to you, ask for a sketch.

It gets worse; with a powertrim you basically have no height adjustment, so the position where the propshaft exits the transom into the powertrim is cruicial for the running attitude.

Assuming your props will be between 45 and 51 mm, you should be able to adjust the height (not the angle!) of the propshaft by half the difference, which is 3 mm.
The mounting holes in the powertrim can be elongated, allowing the mounting plate to slide up 3 mm.

The flare in the wetwell will have to accomodate that height difference.

The purpose of this exercise is that you exit the transom at the height corresponding with a 45 mm prop and that you're able to slide the powertrim up to suit a bigger propsize if required.
I deliberately neglect smaller props, as these won't give you the speed you'll want after trying a 42 mm one...

It gets worse still; in order to keep the propshaft in the middle of the transom, in stead of offsetting it to the right to counteract propwalk, which is a good idea by the way, I would suggest going the path of a lot of German boaters by leaving the exit of the propshaft in the center, but moving the motor (and propshaft) to thr right, creating a small angle of 2-3°, by which the propshaft/powertrim point towards the left (viewed from behind.

Reason for this is my experience with offset drivelines; it is very hard to know in advance how far the offset should be, all my boats have it and with the growing power installed, I always get beyond the point where the offset works and the rudderblade can stay straight for straight running...
Once the power installed get beyond that point, I have to steer left to run straight.
This upsets the running attitude of the boat in question to no end and spontanious flips 'out of the blue' happen ofter as the speed goes up.

Installing the drivetrain at an angle makes the correction, when more power is applied, grow with the speed building up.

Think about it.

Regards, Jan.

[Gaci4]

I got the impression that as long as the stuffing tube  was able to move freely at the end of the boat it just ment sealing the hull some how.
I know now that the stuffing tube can be fixed solid up near the motor end and left to dangle at the transom only being fixed in place by the stinger or strut. I may buy a strut as the fixing holes are no where near the wet well hole and as I'm making the transom high it should be ok to fix onto.
Is there any struts I should steer clear off.

[martno1fan]

Ive never used a wet well all my boats use a flex cable setup straight out the transom into the stinger or strut,the hole in transom is a slight oval to allow a bit of up and down adjustment and i seal the hole with flexable sealant ,never had any problems with that setup.At the motor end the tube is fixed ,you can either use a t bar or fix it in using a larger diam sleeve and a bit of glass cloth tape and epoxy as in this pic.

[Gaci4]

Right let me get it straight in my head, you've got a flexishaft running in a Teflon tube within inside a brass tube(the usual set up) Then the hole lot is placed inside a close fitting brass tube which is fixed permently  inside the boat. .

[martno1fan]

Not all my flexis have a teflon liner some are bare brass tubes i then use a small sleeve of the next size up tubing thats glassed into the boat,i just cut a bit of ply to set under the tube at the right angle once tubes bent to meet the motor then epoxy it in and glass over the whole lot , the prop shaft then slides inside that, if its a snug fit it works fine if its a tad loose i put a bit of pu adhesive on the prop shaft tube just enough to hold it so if need be i can still pull it out to swap it if i ever need to. Or you can just buy a t bar to hold it like this one in the pic and no need for the sleeve but you do need some rails fitting inside the boat to attach the t bar to .

[Gaci4]

Cheers Martin

[martno1fan]

Always more than one way to skin a cat as they say but whatever works at the end of the day  .

[Gaci4]

HI guys, been on holiday for a week just got back, now sold house so will have to put the build on hold till moved now. If you find any info out that could be useful please let me know 

[pompebled]

Ah! The joy of moving...

Let us know when you're back up and building.

Regards, Jan.

[Gaci4]

 

[Tombsy]

I have a flooded stuffing tube on my 10s mono, I used a carbon fibre tube with the brass epoxied in. It's been working very well I won all my heats against nitro boats on the weekend :)

[pompebled]

Hi Brian,

That's mean, even if the pilots of the nitro boats have the same skill level as you, they don't stand a chance against the torque of an electric set-up...
Congrats on your wins!

Care to share your set-up with us?
Please include hull size and propchoice.

Regards, Jan.

[Tombsy]

Sure Jan no problem, it's an older 42" Twincraft hull made for .45-.67 nitro engines. The motor is a ridiculously large Neu 2230 with a 300 amp Swordfish Pro+ esc. I'm only running an Octura X445 prop but it has lots of speed and the motor comes back only lukewarm after a heat. I had about 25% remaining in my 5000 mah 5s packs ( 2 in series) after a 6 lap 1 mile heat.

[pompebled]

Thanks Brian,

I gather it's the 752Kv version on 10S?

Just curious; how long is the average run time over these 6 lap 1Mile heat?

Regards, Jan.

[Tombsy]

Yes it's the 725 kv, I also run a 1527 850kv on 10s in a scale Smokin Joes hydro.
I'd say about 2 and half minutes or so for run time allowing for the 30 second start and possible penalty laps. :) I had about 25% left in my packs using two 5s 5000mah packs.