'Unleaded' For G/A..??

[A Squared]

Originally Posted by Jabbawocky

Ohh and by the way all those big old radials can have the Hi-Blower unleashed again on this stuff. It out-performs 100LL and the old purple stuff you might remember Leadslead.

Not true. Hi blower had nothing to do with higher power settings. On the DC-6* (R-2800-CB16 and CB17) high blower resulted in lower power and was not permitted at takeoff power (except above 10,000 ft, and at a greatly reduced MAP, RPM and Power output) Hi-Blower was there to take over in climb and cruise when the low blower ran out of steam at altitude. You'd reach WOT at climb MAP at about 12-13,000 ft in low blower.



*Which I flew for 8 years in all 3 seats

[Jabawocky]

A Squared

Correct, and that was my mistake, the Connie runs reduced MP of 52" on 100LL

There must be a warbird or something like a T28 that runs a reduced supercharger setting that I am confusing it with. That will bug me all day now.

Thanks for pulling me up on that.

[Jabawocky]

what plug is going to be needed for G100UL if it becomes widespread?

As best I can tell you will change nothing in the plugs. I do not know this for certain but as I understand it, the test flying has all been done with a standard engine and plugs in both planes. Walter will probably confirm this if he wanders into this thread again.


Checkers..... good catch! I meant to write Lead Bromide. Spend so much time time taking the you know what out of a famous report I end up repeating it. It would appear there is such a thing, (lead (II) oxybromide Pb3O2Br2) but we should be calling it Lead Bromide (PbBr2).

My bad again

[Dexta]

Everyday practicalities...

What I want to know is... I have a O320-E2D running on PULP98 (with appropriate STC);
1. The STC (petersen) states to run a tank of AVGAS every 70-75 hours. I think it says because of the valves. Now this has been proved wrong, should I still do this to observe the requirements of the STC or not bother any more?
2. I only have a single CHT & EGT, I can lean it out to I get an RPM drop, which corresponds to roughly peak EGT. I run the engine around 70-75% power (2500 RPM @ 2500', 2600 RPM @ 5000', 2650 @ 9000') this is as per the Cessna manual. Now the manual was written for 80/87 AVGAS, can I assume PULP98 is close enough as to not make any difference, or should I do something different?
3. Re spark plugs, I am using REM38E, should I change to a different plug or not?
P. S. The engine appears to be running fine, CHT's around 350F in cruise, 400F in long climb (full rich), 30 litres an hour.

[Walter Atkinson]

The G100UL fuel will run with the 38 heat range plugs just fine. It will also run fine on RGB29 plugs. The heat range was upped to burn off deposits. If one runs the mixture appropriately LOP, the cooler plugs will stay clean. Cooler plugs are less prone to cracking ceramics and leading to pre-ignition.

[Walter Atkinson]

Exhaust stain color in autos is affected by the catalytic converters. The exhaust deposit color in aviation engines is a result of mixture more so than anything else.

[Walter Atkinson]

There are a lot of OWTs about needing lead in the fuel to coat or cushion valves. ALL of these OWTs have been debunked. There is no science to suggest that the Peterson STC accomplishes anything by running a tank of 100LL every so often. It doesn't hurt, but it doesn't help, either.

[Walter Atkinson]

BTW, there is mounting data that running the coolest plug possible (that does not foul) is a good idea. If you run LOP, you can run a much cooler plug since it will not be fouling anyway!! We have had good service running NA and turbo engines on RGB29 and even 27 plugs as long as the engines are run LOP. If you are a ROP operator, you will probably find that the cooler heat range plugs will be fouling. The higher the heat range, the greater the possibility of pre-ignition from a damaged plug.

[dubbleyew eight]

walter that all sounds good.
I'm just about to buy a new drum of avgas.
can we get a drum of G100UL to try yet?

I think it was the antarctic ice bubble samples that proved conclusively that there was no lead in the atmosphere until we started using tetraethyl lead in fuels. we can fix that.

[Jabawocky]

W8,

No the G100UL is not in production yet. There is an enormous effort being made to have the FAA certification done by the end of the year but it could take longer. Avgas will be around a little while longer although if Shell in Geelong shut the refinery, we will be left with BP Kwinana and Singapore.

So the sooner the better for us I reckon.

[dubbleyew eight]

ok we'll wait.

(but stuff me if we can use 91 octane ordinary motor fuel without problem let's get a move along.)

[A Squared]

Originally Posted by Jabbawocky

the Connie runs reduced MP of 52" on 100LL

Yes, we ran at a max of 59.5"Hg for a wet takeoff with 100LL vs. 62" for an additional 100 hp/eng. if we had 108/135

[Andy_RR]

What's this latency of which the knowledgeable speak?

I've seen my fair share of indicator diagrams and destroyed enough pistons and barrels with knock in my life developing engines, but I've never come across the term.

Somebody care to explain?

[Flying Binghi]

via dubbleyew eight:

...I think it was the antarctic ice bubble samples that proved conclusively that there was no lead in the atmosphere until we started using tetraethyl lead in fuels. we can fix that.

I'd like to see a reference for that dubbleyew eight.

Considering volcanoes emit lead to the atmosphere i wonders how none were found in the Antarctic ice record. Perhaps volcanoes are new to Antarctica...










.

[dubbleyew eight]

my father warned me about people ruining good arguments by insisting on facts.

it was a comment by one of the climate wallahs during a documentary.
it was on the telly. they wouldnt lie to us would they.

[le Pingouin]

People far over-estimate volcanic contributions and far under-estimate human contributions.

Volcanic: 1200 tons Pb per year

Natural soil dust: 1400 tons Pb per year

Industrial: ~300,000 tons Pb per year

Magnitude of lead flux to the atmosphere from volcanoes

Over-estimating volcanic activity leads to people swallowing this whopper:

When the volcano, Mt Pinatubo, erupted in the Philippines in 1991, it spewed out more greenhouse gases into the atmosphere than the entire human race had emitted in its entire YEARS on earth

The reality is Mt Pinatubo: 0.05Gt CO2, human activity: 30Gt per year.

[Flying Binghi]

via le Pingouin:

...Over-estimating volcanic activity leads to people swallowing this whopper:

When the volcano, Mt Pinatubo, erupted in the Philippines in 1991, it spewed out more greenhouse gases into the atmosphere than the entire human race had emitted in its entire YEARS on earth

The reality is Mt Pinatubo: 0.05Gt CO2, human activity: 30Gt per year.

News to me. le pingouin, atmospheric CO2 levels have been fairly well documented of late. Seems to me the increase of CO2 is all due to humans. Considering the atmosphere is still in a CO2 deprived state (plants grow better, need less water and produce more food at 1,200 ppm) i think we need to release a lot more yet.

Moving on...

via le pingouin:
...Volcanic: 1200 tons Pb per year. Natural soil dust: 1400 tons Pb per year.
Industrial: ~300,000 tons Pb per year...

For the discussion we'll run with those figures

Now, le pingouin. How much lead is used in Australia's avgas every year ?









.

[A Squared]

Now, le pingouin. How much lead is used in Australia's avgas every year ?

Your question got me curious.

Without spending a lot of time double-checking numbers the internet told me that 100LL contains 2 grams of TEL per US gallon. And the the US Avgas consumption (yes I know you asked about Australia) is 186,000,000 US gallons/year so that gives 372 tonne of TEL. According to my poorly remembered chemistry, Lead is 78% of the mass of TEL, so that would be 290 tonne of lead. Not as much as volcanoes, but not vanishingly insignificant either.

As far as Australia itself, one source I saw put AU avgas sales at about 80Ml/yr or about 21,000,000 US gal, which is about 11 percent of the US consumption, so that suggests roughly 31 tonne of lead for Australia.

[le Pingouin]

In 2010-2011 we produced 91Ml of AVGAS

http://www.bree.gov.au/documents/pub...ralia-2012.pdf

Doesn't break it down into type so pluck 0.7g/l Pb (from BP product handbook)

Yields ~60t Pb.

I think you'll find your claim about more food and less water at 1200ppm is rather less straightforward than you think.

[Old Akro]

Doesn't break it down into type so pluck 0.7g/l Pb (from BP product handbook)

This is pretty easy to get this from the oil company TDS

Shell 0.55 g/l
Mobil 0.53 g/l max
BP 0.52 g/l

This reduces your figure from 60t to 47t.

The consumption figure for the US is about 360t of lead. (186,000,000 gallons = 707,000,000 litres).

60t vs 360t is too high a %. I would expect that Australia should be about 10% of the US. But, the figure you quoted was production and not consumption. Consumption figures are readily available from the Petroleum institute or the ABS, but I've run out of time.

I also question your earlier figure of ~300,000 tonnes of lead per year going into the atmosphere. This would represent around 10% of total lead production.