Wire drives

[Grimracer]

Its my understanding that cruciform drives are only good for around 12K.. Be good to see how this plays out.

Grim

 

[dr gary turner]

Have been running a wire drive in my 20 40 and F hydros for a couple of years.

No major issues.
Set up as mentioned is critical,

 

[ACTION JACKSON]

So how much can you bend a wire drive & besides weight savings, what is the advantage of this setup. Can these be used in a aeromarine cat. Do you use a special strut. & do you have to come up with a way to keep thrust off electric motor bearings.

 

[dr gary turner]

So how much can you bend a wire drive & besides weight savings, what is the advantage of this setup. Can these be used in a aeromarine cat. Do you use a special strut. & do you have to come up with a way to keep thrust off electric motor bearings.

Main benefit is less drag, but critical set up and maintenance.

 

[DON MAHER]

Has anyone done an actual back to back test between the cable and the wire drives? If so how were they done? What were the results?

 

[Mark Anderson]

That looks like a lot of unsupported weight. Could you not just put the Lovejoy spider directly on the shaft and eliminate the collet?

 

[RaceMechaniX]

Has anyone done an actual back to back test between the cable and the wire drives? If so how were they done? What were the results?

Don, I have done this on electric boats where we have datalogging in the ESC's to show back to back results. It can be considerable! Especially for a long 1/4" cable versus 1/8" wire on Thunderboat or sport hydro. It can be 70-100W on a well designed flex cable system, but I have measured over 500W in the worst case. i.e. long 1/4" cable with fresh grease.

 

[DON MAHER]

Thanks for the reply Amigo.
Due to my lack of knowledge of electric boats (Electricity in general) can you give me an example of say RPM or MPH?
See you in Texas!

 

[DougSick]

So how much can you bend a wire drive & besides weight savings, what is the advantage of this setup. Can these be used in a aeromarine cat. Do you use a special strut. & do you have to come up with a way to keep thrust off electric motor bearings.

 

[DougSick]

Re; Using in a Catamaran.

I have two electrics with .078 wire drive I built myself. P hydro and P mono. I'd say that a wire drive in a big cat would not work well as the ones I've seen have very tight radius for the stuffing tube. The whole trick to a wire drive is keeping the bend as little as possible. The depth of the tunnel in a cat ads a lot of bend when compared to a hydro or mono. The motor would need to be mounted very low, and near the front. Mounting 2 motors in the sponsons would keep the bend low. If it's a big cat, you would have to up the size of the wire making it much harder to bend. Big gas boats run up to .125 wire. The drag on the inside of the stuffing tube would be pretty high for a motor mounted in the centre of a cat. Probably best to stick to flex cables.
The big upside for wire is you don't have to leave a gap at the strut. Use a Teflon/Delrin thrust washer to minimize drag on the strut.
Here is my mono bottom end. I use ball bearings on a .187 SS shaft. The brass ferrule at the front bridges the wire to the shaft. .078 on one side and .187 on the other. The wire is scored and set .5 inch into the shaft and then the ferrule is soldered to the wire and shaft with Staybrite (low temp). I have a lot of grip in this case so the wire should stay put. There is a brass tube separating the single front bearing and the three at the back. I have a 4-40 screw through the top of the strut where the brass tube is located, which allows me to lube the bearings and it prevents the shaft from falling out should the wire break. The wire runs inside a Teflon tube to reduce drag. Very little grease is needed so the whole driveline drag is minimal.

 

[ACTION JACKSON]

Thanks Doug for taking time to explain ins & outs of wire drive on cats. Guess they have there place.

 

[RaceMechaniX]

Thanks for the reply Amigo.
Due to my lack of knowledge of electric boats (Electricity in general) can you give me an example of say RPM or MPH?
See you in Texas!

Don it was worth about 600RPM on a 20kRPM big boat swinging gas size props. This was that Hyperformance Thunderboat I ran for a while. It was a long 30" 1/4" diameter shaft versus a 3mm wire with bushings every 3".

 

[DON MAHER]

Tyler,
Thanks that is exactly what I needed to know because I have been looking into changing my T-boat over to a wire system! Hope to have change done for the “Shootout” in Texas.

 

[RaceMechaniX]

Don, it's a no brainer especially for a Thunderboat with a long gentle bend in the driveline and nice straight shot into the strut.

 

[DON MAHER]

My thoughts exactly! Thanks again for sharing your knowledge Amigo!

 

[DON MAHER]

Tyler, where do you get the 3mm wire from and is it a special wire?

 

[RaceMechaniX]

Don, I got the 3mm wire from Germany many years ago before we had Brent producing the his SFD drives. All the 1/8" wire comes from Brent.

 

[DON MAHER]

Ok thanks, I’ll check with Brent for what I need.