LH707330 wrote:

Another thing to add, diesel engines, partly due to the higher compression ratios, tend to be heavier for their power output due to their beefier structure. While they burn less fuel, their addition to empty weight means that you pay a penalty on short trips and would gain more on longer trips. Most small planes are flown for <2-hour flights, so the empty weight benefit is big.

GalaxyFlyer wrote:

That and in the US, GA is so large and so filled with relatively inexpensive old planes that a couple of diesel models don’t have much impact

math341c wrote:

GalaxyFlyer wrote:

That and in the US, GA is so large and so filled with relatively inexpensive old planes that a couple of diesel models don’t have much impact

What do you mean by "impact". Efficiency, pollution or?

N1120A wrote:

LH707330 wrote:

Another thing to add, diesel engines, partly due to the higher compression ratios, tend to be heavier for their power output due to their beefier structure. While they burn less fuel, their addition to empty weight means that you pay a penalty on short trips and would gain more on longer trips. Most small planes are flown for <2-hour flights, so the empty weight benefit is big.

Nah, weight isn't much of a factor. Diesels are ridiculously efficient. If anything, weight helps the CG. The DA62 is like a modern Twin Comanche, only with much more in reserve and more space.

The real issue is price. A DA50 is $1m. A used Bonanza is $200K. That is a massive difference.

LH707330 wrote:

N1120A wrote:

LH707330 wrote:

Another thing to add, diesel engines, partly due to the higher compression ratios, tend to be heavier for their power output due to their beefier structure. While they burn less fuel, their addition to empty weight means that you pay a penalty on short trips and would gain more on longer trips. Most small planes are flown for <2-hour flights, so the empty weight benefit is big.

Nah, weight isn't much of a factor. Diesels are ridiculously efficient. If anything, weight helps the CG. The DA62 is like a modern Twin Comanche, only with much more in reserve and more space.

The real issue is price. A DA50 is $1m. A used Bonanza is $200K. That is a massive difference.

When they're designed around the diesel it's fine, the issue is when you want to re-engine something. An IO-360 weighs 258 #, while an AE300 weighs 410 #. In something like a 172, those 152 # eat into your useful load if you want to take 2 buddies for a $100 hamburger.

You're right about the price of used planes, there's a bunch of well-maintained ones out there for a price differential that would pay for a lot of fuel. The DA50 looks cool though, I hope they succeed with that design.

N1120A wrote:

LH707330 wrote:

N1120A wrote:

Nah, weight isn't much of a factor. Diesels are ridiculously efficient. If anything, weight helps the CG. The DA62 is like a modern Twin Comanche, only with much more in reserve and more space.

The real issue is price. A DA50 is $1m. A used Bonanza is $200K. That is a massive difference.

When they're designed around the diesel it's fine, the issue is when you want to re-engine something. An IO-360 weighs 258 #, while an AE300 weighs 410 #. In something like a 172, those 152 # eat into your useful load if you want to take 2 buddies for a $100 hamburger.

You're right about the price of used planes, there's a bunch of well-maintained ones out there for a price differential that would pay for a lot of fuel. The DA50 looks cool though, I hope they succeed with that design.

The CD155 used in Cherokees and 172s weighs a comparable amount to the IO360.

Also, useful load isn't necessarily determined by raw weight. CG and aerodynamics play into it. A Bonanza with tip tanks weighs more but has a higher useful load than one without.

math341c wrote:

@N1120A I get it thanks, simply the economics is a problem. But you say JET-A is a new technology for 20 years, for me, it's a lot for still being "New". But is believe Jet-A is successful for SE Piston. For Diamond at least the DA-40 TDI flies like a charm and the cool benefits with diesel engine is also something nice.

GalaxyFlyer wrote:

Saturn 5 F1 engines burned RP-1 which is pretty much kerosene. They used it as it was simple and known fuel.

kalvado wrote:

GalaxyFlyer wrote:

Saturn 5 F1 engines burned RP-1 which is pretty much kerosene. They used it as it was simple and known fuel.

RP-1 compares to Jet-a pretty much same way as distilled apyrogenic water for IV injections compares to rainwater in backyard barrel. Both are water...

Okcflyer wrote:

kalvado wrote:

GalaxyFlyer wrote:

Saturn 5 F1 engines burned RP-1 which is pretty much kerosene. They used it as it was simple and known fuel.

RP-1 compares to Jet-a pretty much same way as distilled apyrogenic water for IV injections compares to rainwater in backyard barrel. Both are water...

Mogas is probably the future of recreational aviation.

N1120A wrote:

Okcflyer wrote:

kalvado wrote:

RP-1 compares to Jet-a pretty much same way as distilled apyrogenic water for IV injections compares to rainwater in backyard barrel. Both are water...

Mogas is probably the future of recreational aviation.

Who said anything about recreational aviation? Recreational pilot certificates are rare, with even the vast majority of LSA pilots choosing to fly them on private instead of sport certificates and simply do so without needing a medical.

kalvado wrote:

GalaxyFlyer wrote:

Saturn 5 F1 engines burned RP-1 which is pretty much kerosene. They used it as it was simple and known fuel.

RP-1 compares to Jet-a pretty much same way as distilled apyrogenic water for IV injections compares to rainwater in backyard barrel. Both are water...

GalaxyFlyer wrote:

kalvado wrote:

GalaxyFlyer wrote:

Saturn 5 F1 engines burned RP-1 which is pretty much kerosene. They used it as it was simple and known fuel.

RP-1 compares to Jet-a pretty much same way as distilled apyrogenic water for IV injections compares to rainwater in backyard barrel. Both are water...

Yeah, it more refined, less sulfur and impurities to polymerize during high temperatures; but it’s kerosene just as
they’re both water. RP-1 would burn fine in jet engine and you wouldn’t go to the moon and both waters would sustain life.

The one issue with using JetA in a piston engine is lubricity in the pumps and injectors as some found out using Jet A in their diesel cars.

From the beginning, the services had disliked the fuels that the researchers had offered them, not only because of their inherent disadvantages, but above all because they weren't gasoline. They already had gasoline and used huge quantities of it —and why should they have to bother with something else? But, as we have seen, gasoline is not a good fuel to b u r n with nitric acid, and the services had to accept the fact. Which they did, grudgingly. But all through the late 40's and early 50's the Navy and the Air Force were busily changing over from piston airplane engines to turbojets. And they started buying jet fuel instead of gasoline, and the whole thing started all over again. They d e m a n d e d of the people designing their missiles that said missiles be fueled with jet fuel.
Now, what is jet fuel? T h a t depends. A turbojet has a remarkably undiscriminating appetite, and will run, or can be made to r u n , on just about anything that will b u r n and can be made to flow, from coal dust to hydrogen. But the services decided, in setting u p the specifications for the jet fuel that they were willing to buy, that the most important considerations should be availability and ease of handling.

Mogas is probably the future of recreational aviation.

math341c wrote:

Mogas is probably the future of recreational aviation.

What do you mean by that? Is MOGAS being the future for GA aviation? Just take any "General Aircraft Knowledge" book and read the disadvantages of using MOGAS for piston engines.

Btw, have you seen the websites of Airbus and Diamond? Diamond has presented their electrical aircraft, the future will be electrical aircraft as with electrical cars.

Okcflyer wrote:

math341c wrote:

Mogas is probably the future of recreational aviation.

What do you mean by that? Is MOGAS being the future for GA aviation? Just take any "General Aircraft Knowledge" book and read the disadvantages of using MOGAS for piston engines.

Btw, have you seen the websites of Airbus and Diamond? Diamond has presented their electrical aircraft, the future will be electrical aircraft as with electrical cars.

I should have been more specific .... MOGAS derived fuels (unleaded!) such as UL91 and UL100.

The trade off of using unleaded fuels gets significantly smaller with modern, high speed electronic controls such as Lycomings iE2 package.

For environmental and cost/complexity reasons, low-lead avgas will go away at some point and that will put pressure on the GA industry to adapt. And it's a lot easier and cheaper to move to UL91/100 and electronic controls (which are retrofittable) than to diesel cycle running Jet A / A1. This was the nature of my point.

N1120A wrote:

Okcflyer wrote:

math341c wrote:

What do you mean by that? Is MOGAS being the future for GA aviation? Just take any "General Aircraft Knowledge" book and read the disadvantages of using MOGAS for piston engines.

Btw, have you seen the websites of Airbus and Diamond? Diamond has presented their electrical aircraft, the future will be electrical aircraft as with electrical cars.

I should have been more specific .... MOGAS derived fuels (unleaded!) such as UL91 and UL100.

The trade off of using unleaded fuels gets significantly smaller with modern, high speed electronic controls such as Lycomings iE2 package.

For environmental and cost/complexity reasons, low-lead avgas will go away at some point and that will put pressure on the GA industry to adapt. And it's a lot easier and cheaper to move to UL91/100 and electronic controls (which are retrofittable) than to diesel cycle running Jet A / A1. This was the nature of my point.

Using the term mogas to describe unleaded aviation fuels is as poorly taken as calling flying light aircraft "recreational." Neither term is accurate or precise. Unleaded aviation fuel, particularly 100UL, is still AvGas. 100UL, which GAMI appears to have finally developed reliably, is gasoline that reliably is the same octane level as 100LL but without lead added to ensure that.

Mogas describes automotive grade gasoline, meaning 87 octane.

Okcflyer wrote:

kalvado wrote:

GalaxyFlyer wrote:

Saturn 5 F1 engines burned RP-1 which is pretty much kerosene. They used it as it was simple and known fuel.

RP-1 compares to Jet-a pretty much same way as distilled apyrogenic water for IV injections compares to rainwater in backyard barrel. Both are water...

You, Sir, win anet for the day. That analogy is hilarious!

To the OP: Diesel engines also haven’t taken over the personal car market either, largely for the same cost reason, although the driver of cost is a bit different between aviation and vehicular use (emission compliance).

Mogas is probably the future of recreational aviation.

Phosphorus wrote:

N1120A wrote:

Okcflyer wrote:

I should have been more specific .... MOGAS derived fuels (unleaded!) such as UL91 and UL100.

The trade off of using unleaded fuels gets significantly smaller with modern, high speed electronic controls such as Lycomings iE2 package.

For environmental and cost/complexity reasons, low-lead avgas will go away at some point and that will put pressure on the GA industry to adapt. And it's a lot easier and cheaper to move to UL91/100 and electronic controls (which are retrofittable) than to diesel cycle running Jet A / A1. This was the nature of my point.

Using the term mogas to describe unleaded aviation fuels is as poorly taken as calling flying light aircraft "recreational." Neither term is accurate or precise. Unleaded aviation fuel, particularly 100UL, is still AvGas. 100UL, which GAMI appears to have finally developed reliably, is gasoline that reliably is the same octane level as 100LL but without lead added to ensure that.

Mogas describes automotive grade gasoline, meaning 87 octane.

Interesting. In Europe, finding car fueling station, with gasoline of less than 92 octane at fueling stations is a challenge, with 95 octane being the mainstay, 98 being premium blends, and plenty of upmarket stations carrying 100 octane.

Okcflyer wrote:

kalvado wrote:

RP-1 compares to Jet-a pretty much same way as distilled apyrogenic water for IV injections compares to rainwater in backyard barrel. Both are water...

You, Sir, win anet for the day. That analogy is hilarious!

To the OP: Diesel engines also haven’t taken over the personal car market either, largely for the same cost reason, although the driver of cost is a bit different between aviation and vehicular use (emission compliance).

Mogas is probably the future of recreational aviation.

Depends on where. If refiners leave 0.5% of sulfur or more in the fuel, diesel personal cars are not a thing.
If regulations are tougher, and diesel fuel is better, personal cars are easily shifting towards diesel. From memory, EU is generally around ~50% of all new car sales diesel, with France as much as 60%?
So yes, in some regions, diesel cars have very much taken over personal car market.
But, these same cars would have a challenge, if constantly run on Jet A, rather than diesel fuel, as lubricity (or rather lack thereof) would prove a problem. These are common rail diesels, often turbocharged.

kalvado wrote:

Phosphorus wrote:

N1120A wrote:

Using the term mogas to describe unleaded aviation fuels is as poorly taken as calling flying light aircraft "recreational." Neither term is accurate or precise. Unleaded aviation fuel, particularly 100UL, is still AvGas. 100UL, which GAMI appears to have finally developed reliably, is gasoline that reliably is the same octane level as 100LL but without lead added to ensure that.

Mogas describes automotive grade gasoline, meaning 87 octane.

Interesting. In Europe, finding car fueling station, with gasoline of less than 92 octane at fueling stations is a challenge, with 95 octane being the mainstay, 98 being premium blends, and plenty of upmarket stations carrying 100 octane.

Okcflyer wrote:

You, Sir, win anet for the day. That analogy is hilarious!

To the OP: Diesel engines also haven’t taken over the personal car market either, largely for the same cost reason, although the driver of cost is a bit different between aviation and vehicular use (emission compliance).

Mogas is probably the future of recreational aviation.

Depends on where. If refiners leave 0.5% of sulfur or more in the fuel, diesel personal cars are not a thing.
If regulations are tougher, and diesel fuel is better, personal cars are easily shifting towards diesel. From memory, EU is generally around ~50% of all new car sales diesel, with France as much as 60%?
So yes, in some regions, diesel cars have very much taken over personal car market.
But, these same cars would have a challenge, if constantly run on Jet A, rather than diesel fuel, as lubricity (or rather lack thereof) would prove a problem. These are common rail diesels, often turbocharged.

US and EU octane numbers are not the same. 87 in US is about 92-93 in EU. It is about different methods of measurements.
And sulfur removal is not free. Cost may be offset by taxation and fees, but that is a totally different story. And issues with additives are a total different story. Black magic of oil and fuel formulations is just that, black magic. Base fractions have to be similar

Phosphorus wrote:

kalvado wrote:

Phosphorus wrote:

Interesting. In Europe, finding car fueling station, with gasoline of less than 92 octane at fueling stations is a challenge, with 95 octane being the mainstay, 98 being premium blends, and plenty of upmarket stations carrying 100 octane.



Depends on where. If refiners leave 0.5% of sulfur or more in the fuel, diesel personal cars are not a thing.
If regulations are tougher, and diesel fuel is better, personal cars are easily shifting towards diesel. From memory, EU is generally around ~50% of all new car sales diesel, with France as much as 60%?
So yes, in some regions, diesel cars have very much taken over personal car market.
But, these same cars would have a challenge, if constantly run on Jet A, rather than diesel fuel, as lubricity (or rather lack thereof) would prove a problem. These are common rail diesels, often turbocharged.

US and EU octane numbers are not the same. 87 in US is about 92-93 in EU. It is about different methods of measurements.
And sulfur removal is not free. Cost may be offset by taxation and fees, but that is a totally different story. And issues with additives are a total different story. Black magic of oil and fuel formulations is just that, black magic. Base fractions have to be similar

Of course sulfur removal isn't free. Neither was taking lead out of gasoline. Still, these are the right thing to do.
Heck, even marine fuels now were desulfurized under IMO regulation, despite shipping industry having to be dragged to it, kicking and screaming...

But if public and regulators are fine with truck exhausts basically spewing sulfurous and sulfuric acid, that's it.

On octane -- I'm not sure I get you right. There are two ways to measure octane -- "motor method" and "bench method" (sorry if I'm getting words wrong, English is not my first, nor second, language, and I'm translating from memory on the go). European way is to put label per bench method (slightly higher), but always document motor method level. You mean, in the US, folks ignore bench measurement, and only document "motor method" measurement?

Phosphorus wrote:

kalvado wrote:

Phosphorus wrote:

Interesting. In Europe, finding car fueling station, with gasoline of less than 92 octane at fueling stations is a challenge, with 95 octane being the mainstay, 98 being premium blends, and plenty of upmarket stations carrying 100 octane.



Depends on where. If refiners leave 0.5% of sulfur or more in the fuel, diesel personal cars are not a thing.
If regulations are tougher, and diesel fuel is better, personal cars are easily shifting towards diesel. From memory, EU is generally around ~50% of all new car sales diesel, with France as much as 60%?
So yes, in some regions, diesel cars have very much taken over personal car market.
But, these same cars would have a challenge, if constantly run on Jet A, rather than diesel fuel, as lubricity (or rather lack thereof) would prove a problem. These are common rail diesels, often turbocharged.

US and EU octane numbers are not the same. 87 in US is about 92-93 in EU. It is about different methods of measurements.
And sulfur removal is not free. Cost may be offset by taxation and fees, but that is a totally different story. And issues with additives are a total different story. Black magic of oil and fuel formulations is just that, black magic. Base fractions have to be similar

Of course sulfur removal isn't free. Neither was taking lead out of gasoline. Still, these are the right thing to do.
Heck, even marine fuels now were desulfurized under IMO regulation, despite shipping industry having to be dragged to it, kicking and screaming...

But if public and regulators are fine with truck exhausts basically spewing sulfurous and sulfuric acid, that's it.

On octane -- I'm not sure I get you right. There are two ways to measure octane -- "motor method" and "bench method" (sorry if I'm getting words wrong, English is not my first, nor second, language, and I'm translating from memory on the go). European way is to put label per bench method (slightly higher), but always document motor method level. You mean, in the US, folks ignore bench measurement, and only document "motor method" measurement?