Opinion Polls: Delphi's Polling Place

Hosted by Showtalk

Opinion polls on all subjects. Opinions? Heck yes, we have opinions - but we're *always* nice about it, even when ours are diametrically opposed to yours. Register your vote today!

  • 4389
    MEMBERS
  • 91877
    MESSAGES
  • 63
    POSTS TODAY

Discussions

New waste laws planned. Do you agree? (SNP)   The Newsy You: News of Today

Started Aug-25 by Showtalk; 10107 views.
Showtalk
Host

From: Showtalk 

Oct-13

Without rereading this whole discussion, did you post this?

WALTER784

From: WALTER784 

Oct-13

I didn't post that story but I did use one of the tables in that story back in my message #101 earlier.

FWIW

Yep. Even when automotive fuel was well under $2 a gallon in March 2020, the price of avgas never fell below about $4 or so.

It was about 60 cents a gallon back when I first learned to fly, and shot up to about 90 cents a gallon when automotive gas hit some 50 cents a gallon circa 1978.

It has a floor these days because it has to be made in a special refining section so some of its grandfathered ingredients (tetraethyl lead) can not cross-contaminate any terrestrial fuel production. Aviation gas is the *only* leaded fuel allowed to be made, because the design of aircraft engines is frozen and can't be altered once the specific engine has been approved without a lot of very expensive paperwork.

Now I know of quite a few aircraft that, over the past 40 years, have been modified during major engine overhauls to be able to handle unleaded gas, although none have been approved to use ethanol blends outside of experimental category aircraft.

So it's a unique little microcosm where two competing bureaucracies have collided in a way that can only be resolved with a very specific exemption carved out.

When you look up aviation fuel prices at airports, you do see more and more that offer "MoGas" for those that have engines for which an approved modification has been made.

The actual modification is really straightforward. If it were an automotive engine, you simply change out the cylinder heads. The new heads have valve seats made of a much harder alloy that can withstand the higher dynamic forces of unleaded gasoline combustion, which also contains a different alloy in the valves themselves, so they don't require the cooling and lubrication properties of tetraethyl lead.

But to change anything in an airplane engine from the original blueprint specifications requires going through as much paperwork as getting a new engine design approved from scratch, and the cost of all the testing and such are well beyond the reach of most individuals and small companies. Unless you have the pockets of Boeing or Airbus Industries or Lockheed, you probably aren't going to have the resources to get a design change and modification approved for an existing airframe and powerplant design.

The exceptions are the airworthiness directive notes, which are generated at the FAA as results of accident investigations. When we had a Beech Bonanza, that involved having to remove various parts from the airplane, ship them off to a laboratory for a specific test, and if it passed, get it put back on, or if it failed, to replace it with a very specific modified part that has a specific approved part number.

That is why that airplane was what we quickly called the "forked tailed money pit". Today I'd call it a white elephant.

Showtalk
Host

From: Showtalk 

Oct-15

There is a home fuel change coming. A dangerous one. I will start a new poll.

In reply toRe: msg 126
Showtalk
Host

From: Showtalk 

Oct-15

WALTER784

From: WALTER784 

Oct-15

Showtalk said...

'Hydrogen in the home would be four times more dangerous than natural gas': government report

We don't need nukes any more... just a spark and kablooeeeeeee... neighborhood/city/state... poof!

FWIW

Showtalk
Host

From: Showtalk 

Oct-15

Yes. Look for my new poll on hydrogen.

TOP