The lead in petrol is only a cheap way of improving the octane rating of the fuel. The octane can be improved by more environmentally friendly means through distillation & blending but this is of course more expensive. The Australian automotive industry used to ake advantage of the cushioning properties of the lead to manufacture valves and seats that were of very soft steel. Fortunately technology has overtaken these practices and we enjoy very good engines in our cars these days which will withstand even LPG and LNG fuels which have no cushioning effect at all. The cushioning of the valves in larger industrial reciprocating engines is achieved by using high ash lubricating oils which achieves the same thing as the lead in petrol. I believe the new lead replacement also has a high ash property for this purpose.
However I don't know how this applies to aviation fuels and octanes of 100. >From memory Super is an octane of 92 and unleaded is an octane of 87. Premium unleaded will come somewhere in between. regards John Ashford Alice Springs ----- Original Message ----- From: "Leigh Bunting" <[EMAIL PROTECTED]> To: "Soaring List" <[EMAIL PROTECTED]> Sent: Thursday, January 03, 2002 11:13 PM Subject: [aus-soaring] Avgas - Is the end in sight? > >From the U.S.-based AvWeb e-zine: > ------------------------------------ > ...AND THAT LEADED-FUEL-BURNING ENGINE OF YOURS > Depending on whom you talk to, there are only one or two suppliers in > the world that produce and ship the tetraethyl lead additive that is > blended into 100LL aviation fuel -- and both are overseas. While no one > > is raising the red flag about current availability of the product, much > of the industry is a bit perturbed that light aircraft are quite > possibly the only remaining users -- certainly the largest user group -- > > still creating a demand for the stuff. This year, a relatively > minuscule $400,000 from the FAA's budget will go for research on > alternate/replacement fuels, while we all cross our fingers and hope > that nothing jeopardizes the supply. > --------------------------------------------- > Food for thought - at Balaklava we run our winches on the stuff too. > -- > Leigh Bunting > Colonel Light Gardens > South Australia > <Open Windows and let the bugs in> > > > > > -- > * You are subscribed to the aus-soaring mailing list. > * To Unsubscribe: send email to [EMAIL PROTECTED] > * with "unsubscribe aus-soaring" in the body of the message > * or with "help" in the body of the message for more information. > > -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information.
