[dzeanah]

> Has the engine in the 172 been improved in that time period? The article says it has not, but I can't imagine using 60 year old tech like that.

It's not the exact same engine, but it's the same technology - an air cooled 360 cubic inch horizontally opposed 4 cylinder engine. Magnetos provide spark, and as far as I'm aware the fuel injection is mechanical.

"Modern" piston engines used in aviation are essentially 1950's technology. They're surprisingly reliable for what they are, but innovation isn't really happening in the piston world.

There was an interesting upgrade being worked on by a couple of guys in Florida. It turns out that the engines in these planes have an expected lifespan of 2,000 hours or so, and can't use gas with ethanol in it, and replacement engines can cost in excess of $20,000; these guys worked on a way to drop in a $5,000 Chevy Corvette engine and greatly increase fuel economy, reduce noise, reduce vibration, and supposedly increase reliability. When they asked the FAA to sign off on it as a replacement they were told that without redundant spark plugs/spark sources it wouldn't be approved. This makes sense when magnetos are expected to be rebuilt every 500 hours, but it killed the Corvette engine replacement idea.

Regulation slows innovation. General Aviation proves it IMO.

[Neliquat]

Dual plug heads, and dual distributor setups are available off the shelf for LSx engines in drag race applications. One wonders why they didn't do the conversion. Although new heads and twin dizzys would easily double the cost, that much reliable power in the aero world would still be a good deal for many.

[FabHK]

FWIW, I once had a faulty spark plug in one cylinder in a Cessna 172 in Ondangwa, Namibia (and no, "burning it off" by running the engine lean on full throttle didn't fix it). So, I flew back to maintenance in Windhoek on the other spark plug, using IFR ("I follow roads") in case the other gave up (which it didn't).

[refurb]

This comment reads like an intro for a very interesting book.

[burger_moon]

So are you allowed to this to your own personal plane (engine swap with non standard engine)? Or do you still have to get FAA approval even for private use?

I guess I'm wondering if there's a grassroots community of people doing engine swaps on their planes?

[sokoloff]

For a type-certified airplane (roughly "one built in a factory"), such an engine swap would require a Supplemental Type Certificate (STC). The process of creating such an STC would require a fairly extensive engineering study as well as flight-testing to prove the new engine was suitable in all regards. During that time period of developing the STC, you would place the aircraft into "Experimental" category to do the testing.

While possible, economically "it's not going to happen".

For non-type-certificated airplanes, there is a large grassroots community around "Experimental-Amateur Built" (E-AB) aircraft. EAA (www.eaa.org) is the largest owner club; they put on "Oshkosh" every year, which is the world's largest fly-in (of E-AB and factory aircraft). In E-AB, the constructor of the airplane has nearly full latitude to choose their engine setup (and to change it later). My limited experience suggests that those who start with tried-and-true aviation-origin engines have a higher success rate with their projects.

[burger_moon]

Thanks for the info!

The Oshkosh eaa meet was always a lot of fun to go watch when I used to live in WI.