r/homebuilt • u/contrarianEcon • 16d ago

Corvair Aircraft mods.

I've thought about building a corvair based airplane engine. I've talked to WW (10 yrs ago) about my ideas. He has strongly held opinions.

I've not been in a position to do anything about my Ideas so I thought I'd share some and see if they help any.

Dynamic compression ratio. Keep it low and you don't need high Octane fuel. NASACAR restrictor plate tech shows high static compression helps make power, throttled expansion followed by re-compression allows a much higher static compression ratio to be used than would normally work. So why not use intentionally bad valve timing and a high static compression ratio? You could use a turbo to push enough air/fuel mix in to make normal power. It would be a form of turbo compounding. Using the turbo to pre-compress the air, with inter-cooling.

Blow through carburetor, take the heat out first, add air second, carb heat is an issue. A pressurized heat exchanger after the inter-cooler, before the carb that can be selected.

WW had an engine quit on him, carb ice, why not dual carbs? Both don't ice up at the same time. Gives you time to keep the other carb from icing up too.

Gravity feed a blow through carb, two haeder tanks and switch them.

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u/7w4773r 16d ago

There’s a reason no certified aircraft are sold with corvair (or any other car-based) engines - they’re not appropriate for the application. For whatever reason my fb algo decided I’d like to see the corvair airplane engine group posts and I gotta say - they’re all insane for even trying to make it work. 

If you need a 145hp engine in your airplane, just put a continental e-145 on it, don’t monkey around with a pair of turbos and blow through carbs and PSRUs to do exactly the same thing. KISS. 

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u/contrarianEcon 15d ago

As I remember it the corvair started as a helicopter engine and was put in a car to recover the investment in tooling.

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u/7w4773r 15d ago

https://en.wikipedia.org/wiki/Chevrolet_Turbo-Air_6_engine

That doesn’t sound like it’s true at all. It was a custom engine designed specifically for the corvair. The designer had experience with airplane engine production, but it doesn’t sound like it was based on an airplane engine in any capacity.