Wire drives for bigger set ups.

[Peter A]

Hi All
I have a question, for those with the knowledge regarding wire drives on bigger boats.
I am planning for my next build, the hull is a 46" mono which I will be using for endurance racing so the power will not be huge. I am looking at using a TP 5660 or 5680 motor of 450-520 kv on 10s. The current draw has to be 50 amps or less for 20 min, so the props will be a little smaller than gas, probably Prather 250-260 or similar.

My thinking is to mount the motor forward in the hull to give me a better ability to adjust CG with the batteries as the hull has 5" rails in it already and putting the motor right at the back will mean a very short 1/4" flex, which is doable anyway and probably easier, but...

What size wire drive, 1/8"? How much power would it take? Could it also run a 5680 size motor if I wanted to? The wire shaft etc I can make up, but where would I get an 8mm-1/8" coupling. The length of the wire would be 15-18" in length I think, I will have to measure the hull and check.

Behind these thoughts is one of reducing driveline friction, therefore reducing wasted amps.
What say any of ye?

[NativePaul]

Not really a bigger boat, but I ran a very forward motor with about 20" wire in my modded JAE.21 with a both with a 3674 pulling about 1kw for 6 minutes and 1527, pulling about 5KW but only for a few seconds, I now run the same 1527 in a 34|" sprintcat with an 18" 2.5mm wire, but again only for very limited runtimes.

While my limited runtimes may make my experiance of limited value to you, I can say that the JAE with about 7" of unsuported wire before the stuffing tube and 11" after it, resonated an whipped badly so it needed a secondary bearing between the stuffing tube and the strut. Whereas the cat with only about 8" unsurported on each side of the stuffing tube, and much more bend in the wire was acceptable without. Both leave teltale contact marks on the wires, so are contacting the stuffing tube.

[TheShaughnessy]

contact Jeff Wohlt, He is the king of wire drives and the matching collets.

[MarkF]

I have converted several big monos and this is what I know. The packs will fit easier in front of the motor. You will be able to adjust the CG easier with packs up front. A wire drive will fail sooner than a cable. In a big boat the saved amps will not be noticed using a wire drive. That's just off the top of my head.

Mark

[Peter A]

I am hoping Jeff will wade in here, just so there is more information available for others to learn from.

Mark, I am using some really big packs, 20000 mah, aroung 4kg of them. This is not the ordinary setup, but it just may be easier and more reliable to run a short flex and keep the motor back. Wire drive reliability is a very considerable issue.

[rol243]

I feel your hull would benefit with the use of a 1/4 inch flex shaft in this set up.

[Peter A]

Yes it will definitely be 1/4" if I use flex, with a stepped shaft to 3/16".

[RaceMechaniX]

I run 3mm wire on my Q mono with a 2280 Lehner pushing a X457/3 all day long. I snapped 3/16" cables left and right and 1/4" was too much friction.
On a 3080 Sniper I used 5mm wire drive supported on ball bearings which was bulletproof.
The key to any of these set-ups is the collet. I had to machine my own long motor collet that used a lot of setscrews to pinch the wire. I also had to add small flats on the shaft to keep it from slipping.

I have not replaced one wire in several seasons of racing. It's also noticeably freer running than any cable.

[dmitry100]

Here’s some new clutches I got... the collets can easily be replaced to support any flex or wire dimension (readily available on ebay) as they’re used for industrial machines, so they’re definitely heavy duty

[Peter A]

Here’s some new clutches I got... the collets can easily be replaced to support any flex or wire dimension (readily available on ebay) as they’re used for industrial machines, so they’re definitely heavy duty

Do you have a link for them?

[srislash]

Yes Dmitry, a link please.

And Peter, I had to sub onto this. Your endurance running is remarkable.

Shawn

[Peter A]

I run 3mm wire on my Q mono with a 2280 Lehner pushing a X457/3 all day long. I snapped 3/16" cables left and right and 1/4" was too much friction.
On a 3080 Sniper I used 5mm wire drive supported on ball bearings which was bulletproof.
The key to any of these set-ups is the collet. I had to machine my own long motor collet that used a lot of setscrews to pinch the wire. I also had to add small flats on the shaft to keep it from slipping.

I have not replaced one wire in several seasons of racing. It's also noticeably freer running than any cable.

Thanks Tyler for your experience. So I am thinking a 3/16" wire, because I can get it, and set a stuffing tube up with perhaps 3-4 bearings. I see that OSE has a 5692 Leo motor at 540kv which would work well I think. Only 3000W-5000 max. The aim is not max power but max efficiency. I should still be able to run 70kph with that setup and a prather 245-250, which is a little faster than I am now. I have the gear and ability to machine parts if need be also.

[Peter A]

Yes Dmitry, a link please.

And Peter, I had to sub onto this. Your endurance running is remarkable.

Shawn

Thanks Shawn, it is a bit of fun. I quite enjoy running for 20 mins at a time, you have to keep the concentration up, especially around the gassers who seem to get some sort of race blinders going on! We had an offshore round last weekend, I was only two laps off the leader of my first heat and 5 laps of the fastest boat. Sadly my second heat ended after about 15 mins when my tow rope came loose and wrapped in the prop with the result being the rotor spun on it's shaft which ended my racing for the day.

[dmitry100]

http://www.hydroworld.de/vb/showthre...zangenkupplung

It's about 40 euros each. The shipping to US was $5-10 bucks. All of them are machined by hand by them.

[RC boat addict]

Hey Dmitry100,For some reason I cant register on hydro world to contact Franz, do you have his email address?
Regards James

[eXoNerated]

Franz Spannagel <franzspannagel@aol.com>