[n86121]

All combustion engines suck in fuel and air, misting the fuel to get the right ratio, light it off with a spark then blow the expanded hot gasses out the exhaust.

Everything else is merely a refinement of that formula.

My son has a highly modified race car. Oversize the turbo. Put a fat 3 in exhaust so it can breathe easier. Some larger injectors, and fuel pump. Reprogram the ECU on a dyno, and all is well. 350 HP out of basically a 120 hp engine.

So it would seem to avoid detonation, one could change the timing on our farm-tractor aircraft engines to accommodate lower octane fuel. While they may not put out exactly the same HP as before, no detonation issues.

Maybe you only get 180HP out of a 210 hp engine?
Maybe you can't go to 30k anymore.

So you de-rate the whole aircraft performance to what the engines CAN put out.
Better than writing off the whole asset.

The experimental guys basically have to do it.
While their engine performance is known,
the capabilities of the aircraft have to be found out empirically
given whatever engine is on it.

So like that, just go the other way.

Yeah, yeah, I know, FAA would never allow that. Blah blah blah..

BUT, subtract the bureaucratic impediments, and the physics seem undeniable.

An aircraft declared experimental is not bound.

What am I missing?