Propshaft to flex shaft / MHZ drive

[Anbjorn]

Use a larger dia ballbearing and make inner dia smaller with fillets.
But a simple piece of brass tube as a liner will work fine too !

Why should I use a larger bearing?

[Gerwin Brommer]

Because you asked : where do I find small ballbearings that can handle the rpm's.
You found them :-)

[Anbjorn]

Because you asked : where do I find small ballbearings that can handle the rpm's.
You found them :-)

[Gerwin Brommer]

The bushings in the drives , do they have a thick "wall" ?
Can they be replaced by bushings, 6mm inner-dia ?
( so you can use 6mm propshafts with 3/16 bore )

[Jeff Wohlt]

Sure you can. You can bore it and use a 5/16" od bearing and 3/16id...which is, I think, 7.9mm

Anything can be made as long as the unit is big enogh...reducing down is easy with brass or a lathed bearing race to take up the slop.

[uncledirty]

Better to run a bare wire, with a small piece of brass tube as a "guide" , or use a
ballbearing to support the wire.

Anybody have any pictures of "pianowire" setup? Tried search, but unfortunately nothing came up, also googled.

[Jeff Wohlt]

Do you just want a pic of the drive? Stb and wire in it?

[uncledirty]

"Better to run a bare wire, with a small piece of brass tube as a "guide" , or use a
ballbearing to support the wire. "

This kind of setup I tried to google and tried to peek from inside hull -pictures. I would see how much brass tube is needed to support and how much curve there is to avoind swinging. I have not seen this kind of setup, but it seems that this would be the setup to my boat.

[uncledirty]

Could 2,2mm flexshaft considered for lehner 1950 or 1940 with 5s or 6s lipos? Instead of 2mm pianowire?

2,2mm flexshaft I would wrap in teflon tube and that packed with aluminun tube.

If this would be the case. Is there any advantages to put flexshaft (or pianowire) running in oilbath? So the tube would be full of easy running oil and washers in the both endz?

[Gerwin Brommer]

Nope, 2,2 flex is for toyboats.
Oilbath : nope.

How long will your pianowires/flexshafts be ? ( from motor to propshaft )

[Simon.O.]

Here is the wire setup in my XL powered rigger. .062"wire The stuff sube is telescoped brass tube with the smallest being 1" of 1/16" tube at each end, this is smaller than needed and on my new cat I have 3/32 as the smallest.
There is very little contact between the wire and the tube and all I use is a wipe of light oil on the shaft before it goes in each day.
This is one of 6 wire drives I run
They are very simple and very easy to make, cheap too.

[sailr]

Is that the way all wire drives are run? Seems and awful lot of unsupported shaft both inside and outside the boat.

[Jeff Wohlt]

I watched Hans Mueller, Hacker boy from germany come over to WI for the race and just smoked everyone with an open wire rigger. We spoke about it and said he has had 0 issues. This dude was faster than fast. Sptter was talking over a half lap ahead to him he was going that fast. It was amazing.

But no...that is not typical for a wire drive in most rigs.

[Simon.O.]

Is that the way all wire drives are run? Seems and awful lot of unsupported shaft both inside and outside the boat.

No vibration issues and the only time a wire broke was at the point where I ground a flat for the drive dog to bite onto. The set screw has now been reground and the new wire is holding.
Multiple 60+ mph passes on most Sundays and this thing is fine. There is more exposed wire on my big Cat and that drive is smooth as silk.

Not one to Hijack a thread but deffo one to explain the merits of wires.

[uncledirty]

Thank you for the fotos. It cleared some of my hesitation. :)

The pianowire between motor and propshaft will be only 15centimetres or max 20. I havent yet decided the exact mounting spot for motors.

btw: I got an anwer from MHZ about enlargeing the 2mm hole in the propshaft to 4,7 for flexshaft. MHZ states that it is no problem since propshaft is 6mm. It is, but the end where the hole for the flexshaft is and where the ballbearings are is only 4,75.... So I would need to cut 20 mm of the shaft, drill exact hole of 4,7 mm and fit the ballbearings to the flexshaft or leave them out...

I just dont know... Too expensive parts just to test, think and retest :) I asked for examples how users have coped with this, but they didnt have any examples with these drives and shaft they recommend. Sorry MHZ, not good...

anyway at least I figured out how to get the other drive to work. There is just some excess metal inside. So when I can get my hands on proper tools I can fix it.