Hunton/ilmor Build

[peterunwin]

Originally Posted by Scand

Impressive. Have you built self-sentering into the steering assembly, or will there be a certain amount of force feedback from the hydraulics? In fly by wire systems it is important for the driver to get some kind of feedback of how much helm you are putting on. Volvo Penta went all out with a full blown force feedback system on the IPS to get the right steering feel.

Hi Scand,
I have built self-centering into the helm unit & also an adjustable friction clutch so that if i don't like the self-centering i can apply some friction to the steering shaft.I haven't built in any force feedback because all the ones i have tried feel false, so the prototype will certainly run without it, also the programming will be much simpler so we will be able to spend much more time at perfecting the variable ratio aspect of the steering system.

Peter

[Boatless-Again]

I think self centering is very imporntant. I have been on many large boats with joy stick steering that did not center the steering when it was released so the operator spent all his time pushing the joy stick right/left/rigt/left/right/left trying to get the boat to stay in a straight line.

A real pain to drive that way.

[sea power]

on the self centering issue, im i right in thinking that the idea is the wheel / legs are to self center when the wheel is released? if so would this not make cruisung hard? i have not been on many race boats but all the pleeasure boats i have been on dont self cetre. as i can imagine it would be annoying to have to hold the wheel all the time at slow speeds. . . .

[peterunwin]

Originally Posted by sea power

on the self centering issue, im i right in thinking that the idea is the wheel / legs are to self center when the wheel is released? if so would this not make cruisung hard? i have not been on many race boats but all the pleeasure boats i have been on dont self cetre. as i can imagine it would be annoying to have to hold the wheel all the time at slow speeds. . . .

Hi sea power,
The self centering on the steering wheel will be very subtly tuned so that it is easy to find the straight ahead position but gradually gets more spring return with greater lock applied.I have been experimenting with elastic bands & different length levers to establish the poundage of spring required which i will then have made in stainless steel.I am also incorporating a small waterproof potentiometer which can be used either to trim the central position or actually steer the boat.The rotary transducers arrived today so had a quick mock-up.

Peter

[peterunwin]

Hi All,
Has been a busy week.Collected carbon fibre angle that will be cut into sections then bonded & bolted to longitudinals to form engine mountings.Also visited Steve Salmon to spec up throttles, shifters & tab indicators which will be manufactured from a mixture of carbonfibre & stainless steel parts, how nice it is to see another british company producing high quality products.

Peter

http://www.candbconsultants.com/salm...%20sports.html

[Matt]

Peter,
My post above about it oscillating wasn't flippant.
It looks like your effectively running a pair of closed loop control systems (ie the electrical and the hydraulic bit). Or is it a single closed loop with a position sensor back to the brain adjusting the demand, I'm not sure.

IIRC a main element of closed loop control theory is ensuring the system is responsive, but not overly so otherwise it goes unstable. I was wondering what type of controller it'll be (PID, etc) and if you are modelling the system at all, or whether you'll just suck it and see and adjust the gains to suit.
M

[peterunwin]

Hi Matt ,

sorry for the delay in responding- we have been rather busy !

The steering cylinders will be connected to the valve via a 4 port counterbalance valve which will eliminate any external forces being able to move the transducers .The microcontroller that drives the proportional hydraulic valve is a closed loop design using PID with feed back and feed forward , this is fully programmable , the program has yet to be written but we are confident we will be able to program it with sufficient sensitivity without it being unstable , the input and outputs are analogue which are infinitely adjustable . We will be testing this on a purpose built test rig before installation onto the boat , but as all parameters are adjustable we can make changes as necessary . You understand of course our need for not sharing every detail , particularly since things may change during development.
The basic objective is to make the system as simple as possible .

Regards

Peter

[peterunwin]

Hi All,
Here are a few photographs of the last few days work.I made 2 wooden frames cut to the angle of the V to sit the engines on to allow easy shimming up to the correct levels so that i can make the engine mountings.The headers are 5" taller than standard which will allow totally straight exhaust pipes these will exit above the swim platform & terminate in a nice slash cut.I will inject a small amount of water into the last 12" of tail pipe in an effort to make it more marina friendly

P.S. THE REAL TAIL PIPES WILL BE MADE OUT OF SOMETHING SLIGHTLY MORE EXOTIC THAN PLASTIC & CARDBOARD

Peter

[peterunwin]

Here are a few more shots of the engine installation.

Peter

[peterunwin]

Hi All,
We brought the two starboard exhaust headers down with us on thursday which we delivered to Bengco @ Hamble Point Marina where John & Gary will cut off the collectors, drop the output flanges by 1.5" fabricate new inner & outer collectors reweld & polish.
Plan A on the exhaust tailpipes was to use 1mm wall titanium inner & outer tubes but despite exhaustive enquiries world wide we have been unable to find a supplier so we are now at plan Z which is to fabricate 4x300mm long,double skinned dry tailpipes with water injector holes drilled in the outboard ends & then slide over the whole assembly 2mm wall carbon fibre tube.We will also fit exhaust gas temperature monitoring into each pipe.As we are stepping up the bore of the carbon fibre quite considerably,injecting the water shouldn't rob us of any power & it will also provide some silencing.As the whole system will be around 70% lighter it won't require any support brackets as the carbon tube is extremely stiff & resilient therefore saving even more weight

Peter

[Jim Brooker]

Originally Posted by peterunwin

Hi All,
We brought the two starboard exhaust headers down with us on thursday which we delivered to Bengco @ Hamble Point Marina where John & Gary will cut off the collectors, drop the output flanges by 1.5" fabricate new inner & outer collectors reweld & polish.
Plan A on the exhaust tailpipes was to use 1mm wall titanium inner & outer tubes but despite exhaustive enquiries world wide we have been unable to find a supplier so we are now at plan Z which is to fabricate 4x300mm long,double skinned dry tailpipes with water injector holes drilled in the outboard ends & then slide over the whole assembly 2mm wall carbon fibre tube.We will also fit exhaust gas temperature monitoring into each pipe.As we are stepping up the bore of the carbon fibre quite considerably,injecting the water shouldn't rob us of any power & it will also provide some silencing.As the whole system will be around 70% lighter it won't require any support brackets as the carbon tube is extremely stiff & resilient therefore saving even more weight

Peter

Hi I don't know much about the Ilmor motors but with some high powered engines with lots of value over lap, and at low RPM, have had water being suck back up a short exhaust pipe on the rear engine and in to the engine when injected with water at the end of the pipe. Just a thought.

[Jim Brooker]

Sorry spelt valve wrong

[peterunwin]

Originally Posted by Jim Brooker

Hi I don't know much about the Ilmor motors but with some high powered engines with lots of value over lap, and at low RPM, have had water being suck back up a short exhaust pipe on the rear engine and in to the engine when injected with water at the end of the pipe. Just a thought.

Hi Jim,
Thanks for your imput i must admit that water scavenging at low rpm is a concern! but havng only 86HP per litre plus very long primary pipes my thoughts are it wil be ok but i will run it passed Ilmor tomorrow & get their view.If they don't like it i am back on the search for titanium pipe.

All The Best
Peter

[larby]

Whenever I feel my project is taking a while, fiddly or costly, I just come here and have a read. Puts it all into perspective really!

Such an interesting insight into what building a top notch boat from scratch involves, keep up the good work and thanks for sharing so much info so far!

James

[Boatless-Again]

Can I ask why you want titanium tubing? The headers that are on the Ilmors are made of 304 Stainless Steel and the ultimate headers are made with Inconel tubing. Tubi out of Italy.

Just wondering.

[peterunwin]

Originally Posted by Boatless-Again

Can I ask why you want titanium tubing? The headers that are on the Ilmors are made of 304 Stainless Steel and the ultimate headers are made with Inconel tubing. Tubi out of Italy.

Just wondering.

Hi Boatless-Again,
As you probably know titanium has a very good strength to weight ratio & therefore i can use much thinner wall tubing.I have calculated the weights of various materials all based on manufacturers specs including the weight of water in the dry sections.
1. Stainless steel exhaust tailpipes two long & two short would weigh approx 95kg including water.
2.Titanium tailpipes would weigh approx 29kg including water.
3.Combination stainless steel/carbon fibre would weigh approx 20kg including water.
4.Combination titanium/carbon fibre would weigh approx 13kg including water.
Also when you factor in the bracketry required to hold up the weight of the stainless steel exhaust tailpipes without putting undue strain on the headers the weight saving is even more pronounced,also because i don't count my labour
i can build the titanium/carbon fibre exhausts for considerably less money than bringing in stainless steel ones from the states plus i like trying new ideas.

Peter

[Boatless-Again]

What is the thermal expansion/contraction rates of the titanium vs. stainless steel or inconel?

Inconel is the best for the thermal conditions but cost have reduced its use in headers other than to those that cost does not factor in. (if we can still say that in today's world)

Stainless will crack due to the heat cycles if the cheap 304 is used and I just wonder if titanium is any better. What about welding the titanium, doesn't that require an atmosphere to be able to weld?

[peterunwin]

Originally Posted by Boatless-Again

What is the thermal expansion/contraction rates of the titanium vs. stainless steel or inconel?

Inconel is the best for the thermal conditions but cost have reduced its use in headers other than to those that cost does not factor in. (if we can still say that in today's world)

Stainless will crack due to the heat cycles if the cheap 304 is used and I just wonder if titanium is any better. What about welding the titanium, doesn't that require an atmosphere to be able to weld?

Hi boatless Again,
Yes you are correct you do need an atmosphere to weld titanium, but i know a man who can.
On the thermal expansion front i don't think it really matters as they are not likely to see temperatures more than 90 degrees c or so.I think most of the header failures in power boats is due to the fact that some designers hang very heavy tailpipes onto the headers & don't support them properly,on our installation i will also incorporate ignition controlled solenoid valves so when you turn off the engines the exhaust tailpipes & headers will drain of water. As all year round boaters this is very important to avoid frost damage,it also has the benefit off if hairline cracks develop with age it won't flood the cylinders.

All The Best

Peter

[Boatless-Again]

I believe (do not say I know) that the headers crack at the point where the flange bolts to the head due to this area being stressed from the welding and it is the first area that see's the heat from the exhaust.

Your motors have the CMI headers and they address this issue with a "cool collar" they call it I think. They seem to have got the cracking issue solved for the most part as people complain less and less.

The ignition controlled solenoid will work fine as people have done several versions of this idea over the years. Someone was trying to patent the use of a pressure valve that operated off the engine oil pressure so when the engine was shut off the valve would open and the water would drain. (hopefully to a thru hull so the water would not be in the bilge)

[Jon Fuller]

Originally Posted by peterunwin

i will also incorporate ignition controlled solenoid valves so when you turn off the engines the exhaust tailpipes & headers will drain of water.

It doesn't need to be that complex.

Cougar used to have a small drain tube from the bottom water feed into the headers (lowest water point) on the Stellings, that ran straight out the transom through a wee skin fitting (X2 per engine) via rubber tube. This had like an 1/8" or 3/16" dia outlet in the skin fitting. during normal running, the losses through this small orifice was insignificant, so didn't affect the cooling performance of the exhaust, but when you switched off, it only took a minute or two to drain the head of water from the exhausts, minimising the risks from ingress via cracked metalwork. And all with no moving parts, or electrics to fail (or buy & rig).

A very Buzzi-esk approach, super simple, but very effective..