100LL Fuel Availability

[Ernie Martin]

Good information in the May and July issues of AOPA Pilot Magazine on 100LL fuel, which leads me to this question: does anyone know the compression ratio on our engines?

To get your attention, one of those issues has a statement I had never seen before, saying that 100LL will "certainly" not be available 1n 10 years. I had seen "probably" but not "certainly".

The issues report on considerable work being done to come up wih a solution, including the possibility of alternative fuels.

What most intrigued me was that most aircraft piston engones (~ 70%) can operate satisfactorily on avfuel without lead -- essentially 100LL but without the lead additive. These engines are those with compression ratios of 7.5 to 1 and below, where the lower octane (much less than 100) would be adequate. Only higher performance engines -- including turbos -- need the higher octane.

So the fix is easy for 70% of the engines (just remove the lead) but much tougher for the remaining 30% with higher compression (here, an alternative high-octane fuel and modified ignition systems with variable timing based on sensor data are some of the solutions being studied).

I'm starting this thread, not just with the compression ratio inquiry, but also as a catalyst for more discussions and views on the subject.

Ernie

[CO_Skymaster]

I've gotten a headache from following this issue. I looked up the compression ratio for our engines (TCM IO-360) on the internet. It's 8.5:1, making it one of the engines that will need modification. I've seen suggestions from FADEC, down to adjusting the timing, to placing some type of insert between the core and cylinder (increasing the volume, and reducing compression ratio). I've decided that whatever happens, I will adjust to the new procedures and specs for running my engine. I know there will be changes, but I don't believe all the doom and gloom surrounding the issue.

Karl

[stratobee]

That could be a solution. A de-rating of the engine and less useful payload.

The new 250hp RR300 turbine in the Robinson R66 is an interesting development and could potentially be a good fit for a turbine conversion for those who have too much money.

[wybenga]

Hi Ernie

Continental "Mobile Al" has made a statement that the TSIO-360 will be approved for UL 94, which is 100LL without the lead. Does not look like a severe problem for our airplanes

Jack
reims P337 N1049D
Malibu N26PG
________
MEDICAL CANNABIS SEEDS

[Ernie Martin]

Great news, although it seems to run counter to what I've been reading, if the compression ratio is indeed 8.5:1.

Ernie

[CO_Skymaster]

If that's true, it would be great news. I haven't heard anything. TCM seems to be very closed mouth about any of their projects. They tend to come out and say it exists, then you never hear anything about it again.

Karl