Quote:
Originally Posted by PilotjohnS
Educate me, why diesel powered?
A Lycoming running lean of peak is really efficient. And relatively cheap compared to turbines and airborne diesels?
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Honestly, I think a good Diesel solution will eventually overtake the avgas powered engines. The complexity of making avgas along with the need to get the lead out eventually will drive the worldwide GA piston fleet toward Diesel.
The energy density of Diesel fuels is better. Lack of lead improves a number of things including greater time between engine oil changes (using synthetic lubricating oils). The cost of Diesel / Jet A is much cheaper (mostly because of the aforementioned complexities of making avgas and the fact that avgas is a relatively low volume product for the refineries that still manufacture it).
What will make a "good" Diesel engine solution? In my opinion:
1. Comparable cost to avgas-burners. While the existing Diesel cycle engines come with a high capital cost, this will be achieved due to economies of scale as the Diesel fleet expands overseas first and then in the US.
2. Manufacturer support. Van's and other kit makers, as certain Diesel solutions emerge, will likely officially support alternate engine packages with firewall forward kits, or perhaps the engine manufacturers will support popular airframes. This will pretty much be a must, as only the most dedicated among experimenters have the guts to try out engines not provided with an easy firewall forward installation, or not proven in aviation.
3. Proven reliability and maintenance costs. This only happens once the Diesel fleet grows and matures.
It's not an overnight change for sure, but I think avgas will be on the way out within 15 years.
The big question in my mind is whether electric batteries/capacitors/flow batteries will ever become competitive in terms of energy density with liquid hydrocarbon fuels. When that happens, for better or worse, IC engines in general will be on their last legs.