On Tuesday, October 16, 2018 at 12:19:58 PM UTC-7, Dan Marotta wrote:
That's very interesting, but I have a question.Â* I've learned from
watching car shows on TV that converting an older engine designed to run
on leaded fuels to run on unleaded fuels requires the cylinder heads to
be removed and new, harder valve seats to be installed.Â* It seems that
one of the uses for lead in the fuel is to cushion the valve seats
against being beaten to death by the valves.Â* I wonder if similar would
need to be addressed by switching from leaded fuel to natural gas.

Heck, as long as I'm asking, I wonder about the auto gas STCs issued for
aviation engines.Â* Maybe they're built originally with harder valve seats.

Can anyone give a good answer?

On 10/16/2018 12:54 PM, Craig Funston wrote:
On Thursday, August 1, 2013 at 11:30:08 AM UTC-7, Tony wrote:
http://www.wired.com/autopia/2013/07/cng-airplane/

could be perfect for a club towplane since we fuel up at the club field 99.9% of the time.
Thanks for the work on this aircraft and the write-up sharing your experiences. I'm curious what's happened in the 5 years since this was posted. Has there been any further learning about the aircraft and has there been any news on certification?

Best regards,
Craig Funston

--
Dan, 5J

Hi Dan, I was asking about the LS1 powered Pawnee. That's a modern engine designed to run on unleaded fuel with or without ethanol.

I may have missed other parts of the discussion related to alternate fuels and certified aircraft engines. If not it would be nice to have discussions about the use of mogas in STC'd engines in another thread.

Thanks,
Craig