Titanium

[dino ferrana]

Was confused where to post this as it is a little fanciful!

 

So assuming money no object (wouldn't it be nice). How much weight would you save by having your running gear made in Titanium? If the Gearbox, Driveshafts, Diff and Propshaft were all titanium was % lighter is it and who could make it?

 

Also I am assuming Titanium pistons, con rods and Crankshaft are possible for a K-Series but who could make them and or how much would it cost? Presumably there would be a longevity benefit in ths as well?

 

[oilyhands]

Titanium is an innapropriate material for pistons and is heavier than Aluminium so there would be little weight saving there, its also less tough than steel so would need to be larger in section to maintain the same strength. Not sure about longevity in a stressed situation like a conrod... F1 teams build no compromise engines but only use Titanium sparingly.

 

If you were using Titanium to replace suspension and / or drive train components, its likely that you would want / need to redesign them in light of the materials properties.

 

Oily

[kenny.]

Oily.........you've just floored me with that one about alli being lighter than titanium. Richard at Europa Engineering sourced an ex F1 Mclaren pedal box fabrication which he grafted on to one of his race cars...it was absolutley incredible how light it was, honestly I was amazed. There was also a guy at a recent show selling large lumps of the stuff. i.e. off cuts off 3 and 4 inch dia. bars and also sqare sectioned off cuts.....it was miles lighter than alli as I can remember from my toolmaking days.........I do stand to be corrected but a block of titanium is ridiculously light in comparison.

 

Kenny SLR

 

PS will be in touch shortly re. the job we spoke about a couple of months ago....car's arrived and is being run in.

 

 

[Paul D Jones]

Its the strength weight ratio, its stronger than ally so it can be thinner so lighter and its a lady dog to do anything with.

 

 

 

Paul.

See My Car Here

[kjp]

 

Strength to weight ratio of steel, ali and titanium all about the same!!

 

Use ali if you can make it strong enough and small enough

 

Titanium if can't

 

and steel if that can't be done

 

KenP

[oilyhands]

volume for volume Titanium is heavier than Aluminium, as pointed out above the strength to weight ratio is rather different, a piston needs a certain amount of mass as a heat sink, if you use a similar section of material the Ti piston will be heavier.

 

Al atomic no 13 weight 26.98

Ti atomic no 22 weight 47.86

Fe atomic no 26 weight 57.85

 

Oily

[Tarek]

Oily,

 

You've got me interested. In cycling, the Titanium frames (alloy I admit) are a fair bit lighter than the Aluminium ones (also alloy) but are considered stronger. Is this all due to the alloy combo? I can't imagine that the laws of the universe change in cycling and motoring. The main difference is in cost, £2000 for a titanium alloy frame, 2/3 less for a top quality ali frame. For the record, the alloy is about 95% titanium.

 

Tarek

[Paul Ranson]

You could make your driveshafts from Carbon/Kevlar (off the shelf technology), and your wishbones from Carbon using flexures to save the weight of rod ends (less off the shelf). Transmission casings from Magnesium are simple.

 

Total weight saving, bugger all!

 

I do know that BAR have being buying silencers for their F1 cars and requested Titanium over Aluminium. I presume there's a small weight saving realised.

 

Paul

[mav]

My pelvis is held together with Titanium Alloy. It does not seem to have slowed me down any!.gif.

 

It is extremely light, and strong. It also has the added bonus of not setting the Airport metal detectors off, unlike my wrist.

 

The X-rays are great.

 

I am worth approx 2 x R500's if you were to scrap me......please don'tteeth.gif

 

Cheers,

 

The idea.gif heavyweight

 

Edited by - mav on 6 Jun 2002 19:47:29

[Morls]

If making light cars is good then light unsprung (especially rotating), bits must be better.

 

Did I hear that Dave Edmands' mad car was getting bike rear calipersquestion.gif

 

This (and similarly sourced discs), would save plenty of unsprung weight for not that much money, also I think my uprights & cast iron hubs weigh very lots.

 

Presumbly with the Triumph (as fitted to many of our sevens) upright fitted to many FF and similar racers there will be a far lighter fabricated thing availible.

 

Without starting up the old rivalry I bet Blatman's Westy has their optional light uprights fitted, surely a good idea.

 

Mark

[Blatman]

Nopeblush.gif

The Westf1eld ally front upright saves almost no weight over the cast iron Cortina jobbie (jobby....whatever!)blush.gif I couldn't believe it either, but it's true. According to the Fluke Motorsport weight database, the ally job is only half a kilo lighter. There is a well documented reason why that half kilo is not worth it, IMO. Alloy hubs are a different matter though, with around 1.5 kilo's per hub to be saved over cast iron items.

[G I5LES]

ali, titanium, and steel products can all be built to the same weight however to get the same responces from a product would mean you have to build to different sizes.

 

Someone bought up mountain bikes earlier and this is a good example

 

one of the lightest frames ever made was by ritchie mountain bikes and it was steel. (This frame only had a lifespan of six months)

 

ali frames are also nearly always lighter than titanium frames because to produce a stiff frame in tatanium you need to oversize the tubes and because titanium is heavier per square inch and very difficult to machine (ie taper) the weight is ussally always more.

 

ali frames however are very easy to machine prior to heat treatment meaning the tubes can be thicker at the ends than the middle than the ends producing a lighter frame (and is alot stiffer than titannium).

 

Where titanium leaves steel and especially ali standing is that it can be flexed infintely without breaking.

 

 

 

Grant Isles

[Peter Carmichael]

You lot will believe anything...

 

Titanium:

atomic number - 22

atomic weight - 47.9

density - 4.5 kg/litre

melting point - 1680 deg C

coefficient of linear thermal expansion - 9 x 10^-6/K

youngs modulus - 110 kN/mm^2

shear modulus - 41 kN/mm^2

yield stress - 200-500 N/mm^2

ultimate stress - 250-700 N/mm^2

 

Aluminium

atomic number - 13

atomic weight - 26.982

density - 2.7 kg/litre

coefficient of linear thermal expansion - 23 x 10^-6/K

youngs modulus - 70 kN/mm^2

shear modulus - 26 kN/mm^2

yield stress - 20-140 N/mm^2

ultimate stress - 60-160 N/mm^2

 

Steel

density - 7.85kg/litre

youngs modulus - 210 kN/mm^2

shear modulus - 81 kN/mm^2

yield stress - 240(mild) to 1600(ultra high strength) N/mm^2

ultimate stress - 480(mild) to 2000(ultra high strength N/mm^2

 

Dural (4.4% Cu)

youngs modulus - 70 kN/mm^2

shear modulus - 27 kN/mm^2

yield stress - 125-440 N/mm^2

ultimate stress - 230-500 N/mm^2

 

 

Peterid=teal>

253 BHP K-seriesteeth.gif, no gearboxbum.gifid=red>

[singlespeeder]

Grante,Would you want to ride a stiff frame for any length of time?If I could build frames like Tom Ritchey,I'd make myself a new one every 6 months.Ti as bike frame nigh on ideal,can be stiff or compliant by altering tube profile,wall thickness,etc

still riding 10yr old Merlin mtb,rides as well as ever,try it

[PeterS]

Oilyhands

Forgive my impertinence, but did you not confuse "toughness" with "strength" in one of your postings?

From all the above, why would anyone go to the expense of using titanium? High strength steel would appear to be good enough, and perhaps easier to work, yet Formula 1 teams do use it for components. I am confused.

[R2D2]

Basic mechanical properties such as elasticity, tensile strength and density don't really give enough information allow material selection.

 

Fracture toughness, weldability, corrosion resistance and fatigue resistance are all quite important depending on the component being considered before manufacturing processes and heat treatments are looked at.

 

Swapping high strength fastners for low grade stainless steel is the classic cock up.

 

The old "aerospace grade" is another good urban myth. Some aircraft parts are really crummy depending on their duty.

 

Unfortunately, Titanium, like all other materials is available in a great many different grades and doesn't always have high strength.

 

The idea that unlike steel or aluminium Titanium has infinite fatigue strength just isn't true.

 

Even the most basic examination of fatigue data shows that the vast majority of engineering steels have a well defined "fatigue limit". This is a stress at below which fatigue cracks will never develop and a component can be considered to have infinite life.

 

Most production automotive parts that are subjected to a flucuating stress are designed using a Goodman Diagram or a Gerber Parabloa so that allowed stresses are kept well within this endurance limit.

 

Titanium and Aluminium do not possess this well defined fatigue limit and the only real way to design safely with these materials is to ask manufacturers for information about their beahviour in this area. Because they are commonly used in high duty aerospace applications there is usually a great deal of published data.

 

It is really quite dodgy to swap materials one for another on a abritary basis that A is always better than B, you really do need to consider the details of the application and to make the right decision and to be sure that the part is still safe.

 

 

 

[edmandsd]

Just in case anyone else is thinking of going the same route re rear bike discs I should tell you the following:

Go for the centrifugally spun iron rotors and not the stainless variety.

Go for the 6mm thick ones and not the more common 4.5mm ones used these days on bikes.

I'm using the same rear Caterham calipers on a disc exactly the same diameter as the solid road discs that i'm replacing(240mm/9.5inch).

Overall weight saving is 2 kgs a side !

[Trevor Phillips]

Firstly, please note I'm not technical... but some practical experience:

My normally aspirated Cosworth head was built with Titanium valves originally from a Hart engine by a very reputable engine builder. Revving to 9200 in race conditions we had two occasions last season of the valves damaging the valve seats by drawing them into the seat.

HT Racing was given the engine and rebuilt it with FDR valves - since then I've had no problems and yet the same rev limit.

Sometimes weight savings and exotic materials can cause unexpected side effects.

Trevor

[AMMO]

Trevor

 

Sounds like the valve seat material was incorrect. I've re-conditioned quite a few Nissan Touring Car heads fitted with titanium valves which also suffered valve seat recession. Once fitted with the correct valve seat material and the valve seats were correctly cut the problem vanished.

 

9,200 rpm with steel valves is not excessive.

 

AMMO

[oilyhands]

Bike engines regularly rev to 13,000RPM plus with ordinary die-formed EN52 steel valves..

 

Oily

[G I5LES]

I dont want to bite but I have owned a pace RC 200 for about 7 years and it was the same weight tripple butted and stiffer than the merlin ti at that time and alot cheaper pace 995ukp merlin ti 2000ukp if I remember rightley.

 

I did not buy the ti hype and even binned the ti products supplied with the frame as they were heavier than the ali parts I replaced them with.

 

But like cars bikes are only as good as the person using them.

 

Grant Isles

[singlespeeder]

Point taken,but I'd always wanted a Merlin,like I'd always wanted a 7,so the cost wasn't issue.

INMHO till you've test rode good ti bike for a week you don't know what you've missed