Hunton/ilmor Build

[peterunwin]

Hi All,
Just back from a long weekend playing with the "OLD CHEETAH". While we were in Hamble we picked up the tension compression strut which Bengco had welded for me, i then machined the ends & mirror polished them, had a trial fit this evening also polished the filler/breather caps i had made from billet aluminium for the trim & tab pumps.

Peter

[Boatless-Again]

Why do you need an extension/compression strut? Are you merely trying to keep the drive line parallel?

[peterunwin]

Originally Posted by Boatless-Again

Why do you need an extension/compression strut? Are you merely trying to keep the drive line parallel?

Hi Boatless-Again,
As the Ilmor engine mounting plates are not particularly strong in the fore & aft direction & there is no plunge in the carbon fibre drive shaft the strut stops end load being applied to the drive shaft.

Peter

[peterunwin]

Hi All,
Finished off the pipework for trim & tab pumps also fitted a dual counter balance valve & started pipework for steering system.I have several jobs running in parallel at the moment so progress can sometimes look a little bit slow. As well as the above i am also working on a test rig for the steering system & modifying the wiring harness on the port engine to make it the opposite hand to the starboard engine so there will there will be no wires crossing the engine bay, although it is a fair bit of trouble it will look a much neater installation.

Peter

[Boatless-Again]

So the polished little valve is a double pilot check valve?

[biffer]

i've been following your build for some time, the attention to detail is second to none, i just hope you've got the balls to abuse it when the time comes (racing that is), i don't know if i could

[peterunwin]

Originally Posted by Boatless-Again

So the polished little valve is a double pilot check valve?

No a counter balance valve works in a completely different way. It is able to control loads applied to it in a completely linear & step free way. A double pilot check valve is quite jerky in comparison & not suitable for this application.

Peter

[peterunwin]

Originally Posted by biffer

i've been following your build for some time, the attention to detail is second to none, i just hope you've got the balls to abuse it when the time comes (racing that is), i don't know if i could

Thanks biffer, you can rest assured that it will be thrashed to within an inch of it's life on a regular basis although probably not racing more along the lines of spectating from the front although looking at other threads regarding the rule changes maybe we could invent a lightweight unlimited cruiser class for it

P.S.
The old Cheetah reached a milestone coming back from Poole today 8000 nautical miles travelled in just over 3 years with no major mechanical breakdowns.

Peter

[peterunwin]

Hi All,
I have been busy making & or modifying hydraulic fittings for the steering system as i am using two steering pumps one on each engine i am installing two non-return valves one for each pump, this is to stop reverse flow when running on one engine.The two flows merge into one after the valves. I also made some special lightweight bulkhead fittings that fit through the transom the four small ones are bleeds for the headers to allow them to drain down when the engines are not running, the two large ones are for the pressure relief valves on the water pickups. I have also been having a mock up of the power steering fluid reservoir which i am making from 3" square aluminium tube this will also incorporate an oil filter & the mounting for the steering valve.

Peter

[Boatless-Again]

Originally Posted by peterunwin

No a counter balance valve works in a completely different way. It is able to control loads applied to it in a completely linear & step free way. A double pilot check valve is quite jerky in comparison & not suitable for this application.

Peter

So you can control the amount of feedback isolation via the adjustment spring? I like your polisher, he must stay busy on this project.

[peterunwin]

Originally Posted by Boatless-Again

So you can control the amount of feedback isolation via the adjustment spring? I like your polisher, he must stay busy on this project.

The pilot ratio is fixed you choose from a selection at the time of order, what looks like adjusters are there to facilitate emergency cylinder movements without power supply.The polishing is done by myself cause i am cheap & usually do it on demand

[Jon Fuller]

You sure you've done all that polishing? whenever I spend an hour or two on the mop, I end up head to toe in black shite & cotton fragments!

[peterunwin]

Hi All,
Been making parts for the power steering fluid reservoir/filter housing had to make a swaging dolly to open the end of the box slightly to allow the filter to slide inside, also made the top & bottom flanges these along with some other parts i have made will be delivered to Bengco for welding, then i will linish and mirror polish them. The filter also incorporates a filler breather and a magnet and is very light and compact.

[peterunwin]

Originally Posted by Jon Fuller

You sure you've done all that polishing? whenever I spend an hour or two on the mop, I end up head to toe in black shite & cotton fragments!

Hi Jon,
Only did the two small manifolds today if i am doing a a lot i wear disposable overalls and a mask but i still end up looking like sooty

Peter

[Boatless-Again]

Originally Posted by peterunwin

The pilot ratio is fixed you choose from a selection at the time of order, what looks like adjusters are there to facilitate emergency cylinder movements without power supply.The polishing is done by myself cause i am cheap & usually do it on demand

So what ratio's do they come in and when does one need them?

[peterunwin]

Originally Posted by Boatless-Again

So what ratio's do they come in and when does one need them?

Hi Boatless,
We use counter balance valves on all the machinery we manufacture for high performance cylinder control. If used in conjunction with a control valve with good metering on the directional control spool you can achieve some quite amazing results. As an example on our drill rig hydraulic guide bush which has a closing force of 10tonnes we can also grip very thin wall steel casings without squashing them provided the operator has good hand eye coordination. As far a pilot ratios are concerned you can have pretty much what ever you want. The ratio chosen for Carbon Cheetah must remain confidential.

Peter

[peterunwin]

Hi All,
Spent a while with the dye grinder dressing & polishing the welding that Bengco did for me, also had a trial assembly of the valve & filter onto the power steering reservoir & mounted it into the boat. I am now ready to make the last of the hoses.

Peter

[Boatless-Again]

Originally Posted by peterunwin

Hi Boatless,
We use counter balance valves on all the machinery we manufacture for high performance cylinder control. If used in conjunction with a control valve with good metering on the directional control spool you can achieve some quite amazing results. As an example on our drill rig hydraulic guide bush which has a closing force of 10tonnes we can also grip very thin wall steel casings without squashing them provided the operator has good hand eye coordination. As far a pilot ratios are concerned you can have pretty much what ever you want. The ratio chosen for Carbon Cheetah must remain confidential.

Peter

PLEASE educate me. In a "boat" steering system, is it necessary to always have a "Balance Valve" or a "DPDC"? When you say "control valve" are you referring to the helm unit?

I understand the twin engine, twin check valve to prevent the back flow as the fluid, like us lazy people, will take the path of least resistance. Why the need and purpose of these valves?

[peterunwin]

Originally Posted by Boatless-Again

PLEASE educate me. In a "boat" steering system, is it necessary to always have a "Balance Valve" or a "DPDC"? When you say "control valve" are you referring to the helm unit?

I understand the twin engine, twin check valve to prevent the back flow as the fluid, like us lazy people, will take the path of least resistance. Why the need and purpose of these valves?

Hi Boatless,
In a small light boat travelling at fairly modest speeds you can manage without check or counter balance valves but the bigger faster boats with out drives such as the Merc and the Ilmor where the propellor sits way behind the steering pivot there is so much sideways force created by the propellors & the lower unit that if you don't control that force with a check or counter balance valve the helm unit would be turned in to a hydraulic motor causing loss of control of the boat & potentially serious injury to your hands. In my installation there is no helm unit as it is flyby wire, the hydraulic circuit is between the cylinders via the counter balance valve to the directional control valve. The counter balance valve has been chosen for this installion because it has zero freeplay, i am also engineering my own tie bar between the drives using stainless steel spherical ball joints this will be mounted aft of the cavitation plates which is the furthest point from the steering pivot.Keeping good control of the drives will save the control valve from constantly adjusting itself to keep the boat on track it will only steer with an input from the wheel not by external forces.

Peter

[peterunwin]

Here's one i made earlier

Peter