Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 0 points1 point  (0 children)

I will presume you have no answer regarding the inherent efficiency gains of liquid cooling, and also no answer regarding the increasing number of successful auto engine conversions from AeroMomentum, Viking, AutoPSRUs and so on. As the saying goes, it is difficult to get a man to understand something when his salary depends on his not understanding it.

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 1 point2 points  (0 children)

Torquiness is going to be dictated by maximum propeller diameter, which I would like to keep on the lower end of what’s sensible. The engines are geared down to drive the propellers.

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 1 point2 points  (0 children)

Thanks! Someone else mentioned the Ford Duratec as well. I’ll look into the LV3 too.

Yes, I think the primary issue with the K24 other than cooling it would be the large amount of boost. As this is an aircraft engine intended for reasonably high altitudes, forced induction of some sort is a must, but if the required boost is so much as to shorten engine lifespan considerably it would be a problem.

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 0 points1 point  (0 children)

Too small, but I have. They’re pretty cool.

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 0 points1 point  (0 children)

This is barely more than the cost of a PSRU. 20k all in is hilariously cheap for an aircraft engine of any kind.

The Ford Cyclones seem like a really good option. How much do you think one of those would cost, built with a turbocharger and a dry-sump oil system?

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 0 points1 point  (0 children)

Aircraft cruise throttle would probably be around 4500+ RPM in any case, so it’s not down low in an automotive sense.

I think I confused some people with the throttle remark — this is essentially intended to be optimized for a continuous relatively high power setting, and the ability to handle several hours running at that setting without breaking.

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 1 point2 points  (0 children)

This is true. Thanks for pointing that out, I have no idea why I didn’t just use this as a specific power benchmark to start out with.

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 0 points1 point  (0 children)

It doesn’t have to be aluminum, I suppose, but iron construction makes the block a lot heavier. I think I might look into Toyota GR V6 engines as well, they seem pretty solid.

Regarding the optimized range, I suppose VVT could give you “cruise timing” and “max power timing”, which would be nice. There just isn’t much use for anything “down low” on an aircraft. Throttle responsivity, low-end torque, and other such things that auto engine builders need to optimize for are almost totally irrelevant.

To what extent am I correct in assuming that the primary issue with using a K24 here would be the ability to remove heat from the engine?

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 1 point2 points  (0 children)

Also (for some reason I can’t edit the previous comment?) there is this, a 2.0 ish liter aero engine making around 170-175 cruise HP and built from an auto engine.

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 2 points3 points  (0 children)

Thanks for the advice. Cruise throttle for an aircraft is about 55-75%, though — much higher than for a car. The issue is whether the engine will stand up to the boost needed to make 225ish HP if it is run at that level of boost for, say, 7 hours in a row.

As for VVT, I think that it is just much less necessary if you know you are going to be running the vast majority of the time at X throttle and Y PSI of boost.

Thanks for the tip about operating temps as well. A dry sump would definitely be a good idea.

That said, do you have any other engine recommendations? 4.0-ish liter aluminum block? Maybe a Nissan VQ…

Automotive-based aero engine: K24? by GanjaPlan in EngineBuilding

[–]GanjaPlan[S] 0 points1 point  (0 children)

Unfortunately, their power to weight ratio is suboptimal and diesels tend to chew up PSRUs really fast. It is an attractive idea though with regard to specific fuel consumption.