Is the "Heavy" Piston Twin dead

By definition, AVGAS* without TEL isn't AVGAS, hence the significant cost-and-time hassles GAMI had to go through to generate STCs for every engine type their customers want to run their G100UL (G = GAMI) on - even through it's (supposedly) a drop-in replacement. That means that, at airports in the states where only G100UL is available, if you haven't obtained (paid for) an STC in advance you can't, legally, refuel your aircraft there.
*For standard AVGAS, start at ASTM D910-21 Standard Specification for Leaded Aviation Gasolines
The gasoline shall adhere to octane rating requirements specified for individual grades, as follows: lean mixture knock value (motor octane number and aviation lean rating); rich mixture knock value (octane and performance number); tetraethyl lead content; color; and dye content (blue, yellow, red, and orange). Conversely, the gasoline shall meet the following requirements specified for all grades: density; distillation (initial and final boiling points, fuel evaporated, evaporated temperatures); recovery, residue, and loss volume; vapor pressure; freezing point; sulfur content; net heat of combustion; copper strip corrosion; oxidation stability (potential gum and lead precipitate); volume change during water reaction; and electrical conductivity.
Last edited by PiperCameron; 31st Jan 2023 at 01:55. Reason: Added ASTM reference
Though it isn't likely to be 'banned' over here because (a) the 'Big 4' oil companies (one in particular) kinda enjoy the monopoly they have right now and (b) GA industry in this country is too small for anyone in power to notice (or care) that we're still using it! Aviation White Paper, anyone??
They're not that noble.. GAMI were prompted to pursue its own alternative because they saw an opportunity (if it worked) to make some serious money.
If Innospec USA stop making TEL for whatever reason then, yeah, GAMI can just wander in and take over whenever they like. So it's politics, not technology or cost or anything else that's the real issue (in the USA as well as here).
They're not that noble.. GAMI were prompted to pursue its own alternative because they saw an opportunity (if it worked) to make some serious money.
If Innospec USA stop making TEL for whatever reason then, yeah, GAMI can just wander in and take over whenever they like. So it's politics, not technology or cost or anything else that's the real issue (in the USA as well as here).
I agree, it's politics that will determine whether LL Avgas will continue to be available in Australia (and the USA). There are plenty of environmentalists in Australia who have the ear of people who have a big and occasionally decisive chunk of votes in various parliaments around the place. It is precisely because the "GA industry" in Australia is so small that it easy to sacrifice without causing too much political damage. And LL Avgas is rounding errors on the oil companies' petty cash float.
I didn't suggest GAMI were in it as a charity. George Braly is a very, very smart man and I hope he gets very, very rich off G1000UL. That's as it should be in capitalist countries.
Just passing out a bit more ammo.. so I'll take that as a compliment, LB 
Given he's been working on it for over a decade knowing that at no time was it a guaranteed success.. and then actually succeeding in getting the FAA to approve STCs for nearly every GA aircraft still flying?!? Wow! Yes, indeed!

Given he's been working on it for over a decade knowing that at no time was it a guaranteed success.. and then actually succeeding in getting the FAA to approve STCs for nearly every GA aircraft still flying?!? Wow! Yes, indeed!
AVGAS refinement is really not that more controlled than car fuel. Different dye, TEL additive, tested at regular stages. However the big difference is its a limited run specialty fuel. So it's more expensive. High perfromance car users used to sneak some from aircraft bowsers as there was less tax making it cheaper than specialty racing fuels that were more expensive for the same reason. There used to be enough demand for several refineries in Australia, now only the one refinery provides AVGAS. Funny for ages they still had green and blue fuel, which were both the same product with different dyes for retail purposes, the green dye fuel having stuffed up in 2001 which created problems for brass parts in fuel lines and carbys. They conned a lot that the green fuel was still 100/130, but was just BP/Mobils version of 100LL. It was even worse when it was coming from the same refinery in different colours.
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I used to drive a 1974 Toyota Celica which had a worked Twin Cam Engine. (Almost Full Race specs) Back in the late 90's Avgas 100LL was cheaper than Unleaded Fuel and the engine pinged like hell on straight Unleaded, so ran the Car solely on 100LL. Car performed very well!!
Then had to switch to Premium Unleaded (98 RON) when I could no longer source the Avgas and didn't really notice any decrease in performance.
High perfromance car users used to sneak some from aircraft bowsers as there was less tax making it cheaper than specialty racing fuels that were more expensive for the same reason.
Then had to switch to Premium Unleaded (98 RON) when I could no longer source the Avgas and didn't really notice any decrease in performance.

This one is an interesting time capsule.
quote from RatsoreA December 2012 "and 35 404's on the register and 33 Caravans. "
Now there are still 33 titans but the Caravan population is 146 !
quote from RatsoreA December 2012 "and 35 404's on the register and 33 Caravans. "
Now there are still 33 titans but the Caravan population is 146 !
Is the F406 still being built? Now that was a beast, basically a PT6 Titan.
The big turbine singles certainly gaining popularity but as the thread is twins with less new options out there what really is the choice?