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Diesel RV-7 & RV-9

K

kgood

Well Known Member
Many you know that I've been flying my Wilksch-powered Diesel RV9 for almost 6 years. I have 500 hours on it now, with very good results, and no issues. It's no secret that I'm serious about diesel / Jet A piston aviation.

The reason for my post is this: I'd like to do an informal poll. I'd like to know if there would be any takers for a Diesel/JetA FWF package as follows:

- Jet A1 burning engine from a proven producer with good customer service history
- Direct drive, Turbocharged, water cooled, delivering 170-180 hp with a relatively simple installation (no FADEC controller, etc.) that can be successfully achieved by most home builders, fuel burn around 6 gallons per hour, installed weight not including mount or cowls of around 350lb (160kg)
- Firewall forward package including engine mount, cooler mounts, cowls, etc. developed by a team experienced with the engine type and the RV aircraft.
- Constant speed prop, let's say an MT with Jihostroj governor/CSU

If this were available at an all-inclusive cost of $70-80K, with delivery in 2015, how many would be interested?

Just wondering...

Kurt Goodfellow
RV9 / WAM 120 diesel
 
$?

kgood said:
If this were available at an all-inclusive cost of $70-80K, with delivery in 2015, how many would be interested?l
Click to expand...

ummm, so......like.......

no plane included, right?!? :rolleyes:

( I guess that's what the cheap diesel helps pay for.......)
 
I have driven a diesel car for the past 6-years and love it. Going to sell it now that I am not driving a lot.

I would like to see a diesel aircraft engine for our RVs but as long as Lycoming is a LOT cheaper, I will stick with Lycoming.

To get me to PAY for a diesel, it will have to be a lower cost plus weigh no more than the Lycomings that Van recommends. It would actually need to be LESS money, LESS weight, and have a better record than Lycomng for me to actually part with any of my money to put one in an aircraft that I am building.
 
Sounds nice, but not for me. Too pricey. I believe that runaway expense is aviation kryptonite.
 
kgood said:
If this were available at an all-inclusive cost of $70-80K, with delivery in 2015, how many would be interested?

Just wondering...

Kurt Goodfellow
RV9 / WAM 120 diesel
Click to expand...


Definitely interested with delivery in 2018. Already looking for a second job to cover the cost :)
 
You will be hard pressed to find a bigger fan of diesel than me. With that said, double the cost of a lycoming would not attract me. We are hard pressed to get our money back out when we sell these planes with a standard build, bumping the build cost by $30k is certainly not going to help.
 
Nice job on the 500 hrs burning whale oil :D
I was all over the experimental diesel wunderchild of the day ( DeltaHawk ) back when I started my build so yes it is very interesting. Still waiting to see an RV with one of those flying for less than I paid for my whole craft. The Vans craft are designed with plenty of power density so a lower power diesel in an RV9 that is turbo'ed to maintain better power at altitude than normally asperated Lycs would be perfect. Like yours I guess. :rolleyes:

HOWEVER, to respond to your question, in my view the higher capital cost must be blatantly and unarguably more than compensated by operation cost such that total ownership cost is less than a Lycoming.

For example, lets assume in both cases we cruise at 135 hp and assume same TAS. The Wilksch site says .43 lb/hp-hr is the best. That gives 8.65 gal JET-A per hr at national average price of $5.52 for a $47.75/hr fuel cost.

Similar .43 lb/hp- hr for a Lyc gives 9.67 gal/ hr (density dif) of 100LL which is a figure I see on about every flight, agrees with my Lycs charts so I tend to believe it. That equates with Nat'l avg price $6.04 to a $58.40/hr fuel cost.

Difference then is $10.65 per hr. Over an arbitrary 2000 hrs, that is $21,300.

While I have not looked at firewall forward costs since I purchased mine, I think $70 to $80K is still more than $21K higher than a 180 Lycoming install.

In order for that price to sell, there must be an additional carrot over and above the cost of operation. In the US, I'm not sure what that is.
 
yeah...

No doubt, the cost is prohibitive, especially compared to the "traditional" engines. The way I see it, there are really only two markets (especially for the EAB crowd) for the diesel at these kinds of prices:

1. The diesel freak. This is me. Someone willing to pay more for the safety, environmental, and day-to-day economy benefits of the diesel. Not to mention the reliability (yet to be proven in many cases). Kind of like the Prius crowd. Someone willing to pay for new technology with a promising future, even if it doesn't "pencil out" right now.

2. The "Outside the US" aviators. There was a similar question posed on another aviation forum, and the response was similar, except for folks posting from outside the USA, mostly Europe, showing some pretty convincing math in favor of diesel. But there, Jet fuel is MUCH cheaper than avgas. And much more available.

My guess is that when 100LL is finally outlawed here, it's replacement will be very expensive. At that point diesel/Jet A will be a more attractive option.

I appreciate everyone chiming in, and look forward to more responses.

Kurt Goodfellow
 
For more simple math:

Let's assume 2,000 hours at 7 gal per hour. That's 14,000 gallons. Diesel will burn about 20% less for a savings of,say 3,000 gallons, so say $15,000 to $20000. I MAY be willing to split that with you because of the risk (not as proven as a Lycoming). So MAX $10,000 premium and that assumes no weight penalty.

HTH

Tim
 
tjo said:
For more simple math:

Let's assume 2,000 hours at 7 gal per hour. That's 14,000 gallons. Diesel will burn about 20% less for a savings of,say 3,000 gallons, so say $15,000 to $20000. I MAY be willing to split that with you because of the risk (not as proven as a Lycoming). So MAX $10,000 premium and that assumes no weight penalty.

HTH

Tim
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Don't forget diesel is a lot cheaper than avgas, as is jet-a. $1-2 difference per gallon is huge over a 2000 hr timeframe. If a mandated replacement for 100ll is more expensive, which it probably will be, the difference will be even greater. I have been eagerly watching av diesels and think there is a potential future, but so far they have all had shortcomings of some sort. Once someone cracks the code and makes a powerful enough and light enough product that is cost effective to buy, I think it will be unbelievably successful in both the ga and UAV markets. Matter of time, I hope....
 
FlyArmy said:
Don't forget diesel is a lot cheaper than avgas, as is jet-a. $1-2 difference per gallon is huge over a 2000 hr timeframe.
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Thats true if you cherry pick the price data. I can do the same and show Jet-A is $5.00 per gallon more expensive.

Airnav national fuel price report

It shows an average price difference of around 50 cents.

As a side note, the fuel pricing alone in the airnav chart would lead to the obvious conclusion that Mogas in a Lyc is the right choice for minimum cost of ownership. (I don't do this.....yet)
 
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As a side note, the fuel pricing alone in the airnav chart would lead to the obvious conclusion that Mogas in a Lyc is the right choice for minimum cost of ownership. (I don't do this.....yet)
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Works for me!

The obvious choice is just too simple.:rolleyes:

Been keeping an eye on diesels for decades, ever since a fellow named Zogg showed up in Oshkosh some twenty years ago.
For me it's price ,weight, reliability and operating cost, not necessarily in that order and compared to a Lycoming of equal horsepower.
 
rzbill said:
...a side note, the fuel pricing alone in the airnav chart would lead to the obvious conclusion that Mogas in a Lyc is the right choice for minimum cost of ownership. (I don't do this.....yet)
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Which is precisely why I bought a low-compression OX-340.

Mogas at $1.80/L vs Avgas at $2.50 vs diesel at $1.65. So what if I need to cart fuel to the airport every now and then?

Avgas might go the way of the dinosaur, but Mogas won't. And most of us can run it now, so any alternative engine needs to be comparable in weight, performance, life-cycle cost and above all, in reliability.
 
rzbill said:
As a side note, the fuel pricing alone in the airnav chart would lead to the obvious conclusion that Mogas in a Lyc is the right choice for minimum cost of ownership. (I don't do this.....yet)
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Mine's not flying yet, but it's getting very close - and that's the route I chose. I'm set up to burn 91-octane premium pump gas WITH ethanol, fuel is plentiful and sells for about $3.80/gal for premium here in west Texas.

I chased the diesel dream for a long time too - but in the end the cost differential is just prohibitive and I can't justify it no matter how hard I try.
 
airguy said:
Mine's not flying yet, but it's getting very close - and that's the route I chose. I'm set up to burn 91-octane premium pump gas WITH ethanol, fuel is plentiful and sells for about $3.80/gal for premium here in west Texas.

I chased the diesel dream for a long time too - but in the end the cost differential is just prohibitive and I can't justify it no matter how hard I try.
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That's my plan and reasoning, too. Lycomings and clones are still absurdly expensive, but that price difference over the diesel will cover my entire panel and a bunch of gas besides...
 
Kurt,

Thanks for your post and sharing your experiences in diesel. I spent decades in diesel design for a major engine manufacturer and have a soft spot for compression ignition power plants.

I think for the CI engine to succeed it must be competitive on it's own. Advantages can be lower fuel weight for mission (7-800 nm) and this requires good SFC. Spark ignited gets pretty good SFC at WOT, so the diesel needs to beat it so the engine weight can be lost in fuel weight. Life: lower temps of diesel allow longer life if operated that way. If the overhaul life was in the 3-4000 hour range, it might not help the typical flyer, but could be traded for higher power.

I think the bottom line is the cost per hour of the for purchase, operation, maintenance, and overhaul.

Keep us up to date on your experiences, these count in gathering confidence in the application. :)
 
Thanks for the comments.

I think when we consider the overall hourly cost to fly diesel vs Avgas, we need to consider the entire flight profile. The Avgas burner uses much more fuel on takeoff and climb. Once at cruise altitude and properly liened (LOP), it can come reasonably close to the diesel, but never match it. The new Wilksch is burning .39lb/hp/hr, which is just about where the Centurion is.

If you follow the progress of the Redhawk trainers (172's repowered with Centurion 2.0 diesel) on FB, you'll see that even with the high cost of the conversion, they are still saving money. With the diesel, they are averaging 5.3 gal/hour in training, opposed to an average of 11 gal/hour with the Lycomings. That's a pretty significant real-world savings, especially when you consider the $1.00/gal avg price difference in the cost of the fuel.

According to Continental, the TBR on their engines should be up to 2000 hours very soon. There are several of their engines still flying with over 3000 hours. With this technology still fairly new, it just takes time to test and prove the engines. As the different engines continue to build time, the TBR/TBO's will continue to go up.

I have just finished and am flying a Glasair Sportsman with the Continental Centurion 2.0S (155 hp). I'm very happy with it. It's really nice just to hop in, turn the key and it starts immediately, the same way, every time. No hot start, cold start, priming, flooding, fowling - nothing. Every start is a normal start. The single power lever is also really cool. Just set it at the desired % of power, and you're done. No mixture, carb heat, prop control; no worrying about shock cooling. Another nice thing is the turbocharger. This engine produces 100% power up to 9300'. The other day I followed an RV8 out of Big Bear, CA (elevation 6752'). It was great to have full power at that altitude. I didn't need near as much runway...

It's nice to see that diesel is gaining traction in the certified world. As the technology matures and the diesel fleet grows, hopefully the prices will come down. The way I see it, if a manufacturer wants to enter the homebuilt market now, they'll need to subsidize pricing in order to make it happen, and I'm just not sure there's much incentive to do that.
Kurt
 
kgood said:
If you follow the progress of the Redhawk trainers (172's repowered with Centurion 2.0 diesel) on FB, you'll see that even with the high cost of the conversion, they are still saving money. With the diesel, they are averaging 5.3 gal/hour in training, opposed to an average of 11 gal/hour with the Lycomings. That's a pretty significant real-world savings, especially when you consider the $1.00/gal avg price difference in the cost of the fuel.
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I'm really sorry because I like (and drive) diesels but this drives me crazy.

From a horsepower standpoint we are comparing apples and oranges. Centurion is 135hp MAX vs a 180 Lyc. Certainly they are going to drink different amounts of fuel since the power levels will have been set different.

Lets compare Granny Smiths and Red Delicious apples to apples.

Assuming the .39 lb/hp-hr figure you stated, plus the fuel consumption of 5.3 gal/hr, the Centurion 172 is cruising at 91HP or equivalent to 50% of the 180Lyc. Assuming for sake of argument that a Lyc would have a bad specific consumption of about 0.5 lb/hp-hr at that throttle setting, then the consumption would be around 7.5 gal per hr. Yes it is more, but not 11 gallons. 11 gallons equates to 75% slopily set ROP on a 180 and the gain of 15% more cruise speed over the Centurion.

The diesel would be a plane that you could get max range on, since you can't cruise much faster than best range speed.

From a practical standpoint I believe the school probably is saving bundles of fuel (yes down from 11 gal/hr) since the flight profile of a trainer rarely includes tuning a Lycoming to best performance. But that is not the same profile that an owner like us would use. Heck, I'm almost to the point of doing the BMP on climb. :eek: Need a little more 'nad fertilizer yet tho'.

Please understand I am not a crazed "Lycoming or nothing" supporter. I think the development of diesels is great. (I want the Sube flat 4 diesel in the US as soon as possible) ;) And I am envious of your turbo. :cool:
 
Bill, I think you misunderstood the intent of my post.

I was trying to point out that that in "real world" scenarios, (the whole flight profile, not just the cruise), the diesel has advantages. I used the Redhawk as an example because it is a documented "real world" scenario. I know that these planes are used for training, not what us RVr's do. But even using your logic, with all being equal, 5.3 gph is still 40% better than 7.5 gph.

The point is that the diesel used less than 1/2 the fuel doing the same mission. I also pointed out that the Lycoming uses substantially more fuel on climb, which would help to explain the difference in fuel consumption - since training involves a lot of take-offs and climbs.

When I tested my Wilksch diesel in a "RVr's real world scenario" against Van's own RV9A, we did a "same day, same way" flight, which included climb and cruise. We flew side by side, exact same flight profile, only we (Marc Cook and I) were 70lb heavier. Ken Krueger from Vans set the rules: "Use every trick you know to cut the fuel burn, and I'll do the same". For me, it was simply full power climb, then set the cruise power at 75% and fly. At the end of the flight, we topped off and we had burned 5 gal, while the factory plane had burned 7.2. We also did a cost comparison for the flight, and, since Jet A was much cheaper, that widened the cost gap even further.

Believe me, I'm not beating up on Lycomings - they are well proven, reliable, reasonably priced powerplants. In LOP cruise, they're pretty darned efficient. I'm only trying to demonstrate that in some applications - even with the higher purchase price - diesels can save money.

Kurt
 
Now that last example is great. Planes flying side by side which means same (or darned close to it) power expenditures. Fuel usage right where the thermodynamics says it ought to be for both craft. Unarguable comparison. That's what I was driving to.

I do get the other example as how a company could save money but the saving was half efficiency (diesel over gas) and half in reduction of craft performance and operation style which muddies the water.
 
deltahawk

Deltahawk was supposed to be the next big thing. Hope you're still not holding your breath.
 
I don't think we're going to see a diesel "aircraft" engine in the same price range as we currently typically see for a new Lycoming (say $20-30G) unless is it a modification of another common engine made for automotive, marine, or ground power units etc. This is mostly due to economies of scale.

Is anyone working to convert the Subaru boxer diesel for aircraft use?

Bevan
 
Bevan said:
I don't think we're going to see a diesel "aircraft" engine in the same price range as we currently typically see for a new Lycoming (say $20-30G) unless is it a modification of another common engine made for automotive, marine, or ground power units etc. This is mostly due to economies of scale.

Is anyone working to convert the Subaru boxer diesel for aircraft use?

Bevan
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The EE20 Subaru has not worked out too well. Broken crankshafts, bearing problems and cracked blocks in 2007 to 2009 models at least. Maybe the problems are solved now. The crank design looks pretty scary for a diesel.
 
rv6ejguy said:
The EE20 Subaru has not worked out too well. Broken crankshafts, bearing problems and cracked blocks in 2007 to 2009 models at least. Maybe the problems are solved now. The crank design looks pretty scary for a diesel.
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Hi Ross,

Are you saying they didn't work out too well in aircraft, or in the vehicle?

Bevan
 
Wow, those pictures of broken cranks are disturbing especially in an automotive environment. I wonder if it's a manufacturing defect that takes x number of cycles to failure, or just a design flaw. Shouldn't be too difficult to redesign for lengevity. I've always thought of subaru as master engineers, but still human evidently.

Bevan
 
Bevan said:
Wow, those pictures of broken cranks are disturbing especially in an automotive environment. I wonder if it's a manufacturing defect that takes x number of cycles to failure, or just a design flaw. Shouldn't be too difficult to redesign for lengevity. I've always thought of subaru as master engineers, but still human evidently.

Bevan
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The crank looks pretty wimpy for a diesel IMO, not what you'd see on a Landcruiser diesel crank. I guess they may have gone a bit too light. Usually the process control is exceptionally good in the automotive world. The goal is 1 defect per million typically.

Subaru has got things wrong before- problems with EJ25 head gaskets, oil pickup tubes falling off, improper mapping leading to piston failures on STis, shortened skirts on EJs leading to cold piston slap etc. Certainly not infallible. The bad thing is they rarely admit to anything so they often lose new buyer loyalty if that buyer encounters issues like this. Might as well 'fess up and do the right thing. They need to do some better QC and validation perhaps.
 
rv6ejguy said:
The EE20 Subaru has not worked out too well. Broken crankshafts, bearing problems and cracked blocks in 2007 to 2009 models at least. Maybe the problems are solved now. The crank design looks pretty scary for a diesel.
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Well, that's disappointing to hear. I've been really hopeful that it would be a good candidate for a/c use. Of course, any new design is likely to go through teething problems, like the very early Mazda rotaries. The only real issue with them over the last 20+ years is Mazda's insistence on using crankcase oil for 'top lube' of the apex seals, and that's an understandable choice since most drivers these days don't know how to open the hood.

If the EE20 has been in production for 7 years, you'd expect a company like Subaru to get it rock solid reliable by now. Please post any updates you may find. If it has evolved into a reliable engine, it should be a pretty good (and affordable) fit for 2 seat rv's.

As to the original question: I think a $30K+ price tag (more than the cost of an entire airframe) for an overgrown VW engine that's been around for half a century is insanity from square one. It's really difficult to justify over twice that for a replacement engine design, even if the replacement is a somewhat better engine.

Charlie
 
rv7charlie said:
Well, that's disappointing to hear. I've been really hopeful that it would be a good candidate for a/c use. Of course, any new design is likely to go through teething problems, like the very early Mazda rotaries. The only real issue with them over the last 20+ years is Mazda's insistence on using crankcase oil for 'top lube' of the apex seals, and that's an understandable choice since most drivers these days don't know how to open the hood.

If the EE20 has been in production for 7 years, you'd expect a company like Subaru to get it rock solid reliable by now. Please post any updates you may find. If it has evolved into a reliable engine, it should be a pretty good (and affordable) fit for 2 seat rv's.

As to the original question: I think a $30K+ price tag (more than the cost of an entire airframe) for an overgrown VW engine that's been around for half a century is insanity from square one. It's really difficult to justify over twice that for a replacement engine design, even if the replacement is a somewhat better engine.

Charlie
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It just appears like this was "drawn" and not "designed". GM's guys learned this multiple times trying to add an injection pump to a gasoline engine. THAT is the design failure here. Diesel engine design is pretty straight forward, but what one can fluff by on in an SI (spark ignited) engine will not fly on a diesel. Each compression stroke is full compression force on the components. Torsionals and fatigue take their toll. On a gasoline engine, at idle, the compression pressure is only about 30 psi due to low manifold pressure. That will be 10x higher on a diesel. Just basics, but if their engineers don't know and don't think, the "design" fails. Sad, but a fact of life that gets repeated. 1/4" crank webs were doomed from the start. It is hard, even for a big company, to justify $4-500 million for design, development, and tooling for a new diesel design.

The WAM was designed from the beginning as a diesel and a big question is how it is meeting the durability expectations in use. Kurt is our guy for that!
 
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What for....

.....except for some exotic dream to do something different, the proposal makes no sense.

I've been down that road and even when it starts out economically sound, the effort is fraught with challenges, inevitable failures and significant cost over runs. If there were no good aircraft engine available it would make sense, but to reinvent a wheel just for the heck of it makes no sense whatever, at least not to me.

I'd rather go flying.
 
BillL said:
It just appears like this was "drawn" and not "designed". GM's guys learned this multiple times trying to add an injection pump to a gasoline engine. THAT is the design failure here. Diesel engine design is pretty straight forward, but what one can fluff by on in an SI (spark ignited) engine will not fly on a diesel. Each compression stroke is full compression force on the components. Torsionals and fatigue take their toll. On a gasoline engine, at idle, the compression pressure is only about 30 psi due to low manifold pressure. That will be 10x higher on a diesel. Just basics, but if their engineers don't know and don't think, the "design" fails. Sad, but a fact of life that gets repeated. 1/4" crank webs were doomed from the start. It is hard, even for a big company, to justify $4-500 million for design, development, and tooling for a new diesel design.

The WAM was designed from the beginning as a diesel and a big question is how it is meeting the durability expectations in use. Kurt is our guy for that!
Click to expand...

The typical auto engine validation tests that all OEMs do involve a minimum of 200 hours (and usually a lot more) WOT running on dozens of examples to prove the design so I could only surmise that the crank failures are due to metallurgical defects or heat treating problems but like I said before, the process control in the modern automotive world is exceptionally good. If the basic design was not sound, all the cranks would be breaking at about the same time and you'd have to redesign the whole engine to use wider webs. So this is a bit of a strange one and Subaru is not likely to say anything much. Generally speaking, automotive cranks never break these days even at triple the stock hp outputs but that is the SI world, diesels are different.

The WAM is looking good for Kurt and the original price was good too. I guess prices have really crept up.
 
I hate to hear that the Sube diesel's having problems. I came so close to buying one and doing the development myself. It seemed like it would make such a fine airplane engine. To me, the biggest drawback was the weight. It's a bit too heavy, with gearbox and cooling system added. I'm sure weight could be shaved off, but it would still be heavy.

I'm glad I didn't try it. After spending a week a the Technify / Centurion factory in Germany, my eyes were opened to the insane amount of research, development, testing, re-testing that goes into making their engines reliable. It was unbelievable.

Why do it, when the current engines do such a great job? This is not some exotic dream just to create something different. This is reality. Whether we like it or not, Avgas is super expensive in other countries, and it will be here in the US as soon as 100LL is phased out. Plus, there are environmental concerns. Eventually something's going to have to be done to make GA more efficient and environmentally friendly. As almost every airframe manufacture knows, along with several engine manufacturers, the best bet is diesel, and they're investing in it. The writing is on the wall, and they know that in order for their businesses to survive long term, they're going to need to have the diesel option available. It'll be interesting to see how it plays out...

With regard to the Wilksch's reliability, so far it's been great. I know of a couple of prop strikes, one pretty severe, with NO damage to the crank. There have been a few factory Service Bulletins, easily complied with, but overall, they've been very reliable. That said, there are only 20+ of them out there running. As far as I know, there's only one out there with more time then mine, an RV9A in the UK with over 750 hours.

Really, by far the biggest success out there is the Centurion, with over 4 million flight hours. Yes, they've had their problems, especially with the receivership, etc, but they have stayed the course. From their website:

"The Centurion-series engines stand out thanks to their unique level of fuel efficiency and their above-average reliability.According to the FAA, engines used in general aviation experience an average of ten engine failures or ?in-flight shutdowns? (IFSDs) every 100,000 flight hours.The shutdown rate of Centurion engines is around 50 percent lower and has been reduced even further since model change from Centurion 1.7 to Centurion 2.0.Taking the period since its introduction onto the market in 2003 into consideration, the shutdown rate for all Centurion engine models is 4.83 every 100,000 flight hours.In fact, measured over the last 52 weeks, the shutdown rate of the most recent engine model, the Centurion 2.0, has been just 0.61 IFSDs per 100,000 flight hours, thus being the most reliable piston engine for use in general aviation.Naturally, the Centurion 2.0 possesses various advantages over the 1.7 thanks to all of the experience gained from the field with its predecessor which was integrated in the development of the 2.0."

Guys (and gals), GA is dying. Something has to be done to make flying more affordable, safer, and environmentally friendly if it is to thrive again. Yes, it is very costly to bring new technology to market, but IMO someone's gotta do it, and eventually it'll bring costs down, efficiency up, and pollution down. I think that's a good thing.
Kurt
 
Just for fun, what would have to be done to convert on IO-320/360 to run on diesel? Would the crank and case possibly work as is? If so, all other components could be built/modified to suit.

Would it have to be turbo'd?

I assume it would have to have EFI?

Is the traditional aircraft cooling system sufficient?

Would the prop would have to be composite?

Oh my! The proverbial can o worms has been opened. :eek:


Bevan
 
Having read all of this thread (thus far) and run both simple and detailed number crunching for a typical Eastern USA 1hr flight with a climb from SL to 7500ft, the diesel comes out at 5.3 gallons vs 7.3 gallons for AvGas.

That surprised me and was not far off from the side-by-side test.

When the cost of fuel is the primary factor, the diesel wins @ $31.25 vs $46.50

... but not by very much when we include zero-ethanol @ $34.35

FYI: The fuel cost + engine cost still favors all of the *gas solutions.

Long term, assuming the elimination of 100LL and little advancement in engines, mitigating with zero-ethanol is a strong contender.
 
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humptybump said:
mitigating with zero-ethanol is a strong contender.
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Why zero-ethanol?

This is something that has bugged me since I started building, when I hear people say it. Granted, for those folks that are buying a built plane (EAB or certificated) you take what you can get - but the EAB buyers still have the option of modifying their bird, and the builders have the option of doing it from the start - we can easily set our planes up for E10 use and burn premium pump gas with ethanol safely.

Maybe I'm just a little farther off in the experimental corner than most, maybe I have a lot more understanding of the chemistry of the fuel and the physics of the engine, I dunno. But it just ain't that difficult guys....

8.7:1 compression, fuel injected, get rid of all the natural rubber components, electronic ignition, your done. Life is good.
 
I agree with Greg; egas can work. However, so can off-road diesel, if you have a way to store/transport it.

What do the numbers look like comparing farm diesel prices to any gasoline?

Charlie
 
Hi Greg - when talking about mitigating "the death of 100LL" I was taking into consideration all of the flying aircraft, not just the experimental category. Plus, as you noted, it's more work and cost to enable "after the fact".
 
rv7charlie said:
I agree with Greg; egas can work. However, so can off-road diesel, if you have a way to store/transport it.

What do the numbers look like comparing farm diesel prices to any gasoline?

Charlie
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Excellent point. Off road diesel works great. In my area, it's comes from the exact same source as on-road diesel, except red dye is added. I'm paying $3.11/gal for it in bulk. I've heard that in some places farm fuel is not as clean as on-road fuel, so it would need to be carefully filtered to run in a plane.

Still, even running on-road (taxed) diesel still saves a lot of money. It's $1.00-1.50/gal cheaper than JET A.

I've run off-road diesel for years in my RV9. It's a bit heavier and packs more BTU's (makes more power, so you need less!) than Jet A, but the engines love it.

When it's really cold, I switch to Jet fuel because diesel will gel long before Jet A will.

I'm not that familiar with Mogas / Egas, but would you have to have a way to store and transport it as well? Or is it available at airports? I know they don't have it at any airports I've flown to around the West. I just have a 155 gal aluminum tank mounted on a small trailer. It has a 12V pump and a filter. Works great. Every few months, I just bring it to work and fill it up. At 5 gal/hour average fuel burn and 100 hrs/year average flight time, a tank of fuel lasts quite awhile!

So, I suppose that when folks are doing the math comparing the cost of flying a diesel to flying a traditional engine on Mogas, it would be best to use the price of red diesel fuel rather than JET A.

Kurt
 
kgood said:
I'm not that familiar with Mogas / Egas, but would you have to have a way to store and transport it as well? Or is it available at airports? I know they don't have it at any airports I've flown to around the West. I just have a 155 gal aluminum tank mounted on a small trailer. It has a 12V pump and a filter. Works great. Every few months, I just bring it to work and fill it up. At 5 gal/hour average fuel burn and 100 hrs/year average flight time, a tank of fuel lasts quite awhile!

So, I suppose that when folks are doing the math comparing the cost of flying a diesel to flying a traditional engine on Mogas, it would be best to use the price of red diesel fuel rather than JET A.

Kurt
Click to expand...

Mogas (non-ethanol) is available at some airports, but certainly not all. You won't find e-gas at any airport, if you've got access to mogas that's the way to go. In my case I fly off a private strip without fuel, so I put a 50 gallon fuel tank in the bed of my pickup (very common out here in west Texas) with an electric pump, and that becomes my mobile fuel station. I can keep it topped off in town on the way to/from work with good premium fuel and use that to fuel my plane.
 
Where has this gone?

I've read about many alternatives, but bang for buck still points to using a rebuildable, first runout, Lycoming for most RVs. I applaud the spirit of inovation and pushing the envelope. With the advances by EFII toward FADEC type operation, the current prices of non ethanol MOGAS and the availability of 2nd/3rd owner kits for sale, the price of this diesel package is more than that of a flying VFR RV with a complete EFII system.

Hope this package becomes more affordable and a competitive alternative.
 
N62XS said:
I've read about many alternatives, but bang for buck still points to using a rebuildable, first runout, Lycoming for most RVs. I applaud the spirit of inovation and pushing the envelope. With the advances by EFII toward FADEC type operation, the current prices of non ethanol MOGAS and the availability of 2nd/3rd owner kits for sale, the price of this diesel package is more than that of a flying VFR RV with a complete EFII system.

Hope this package becomes more affordable and a competitive alternative.
Click to expand...

That's still a mostly accurate assessment, unfortunately.
 
N62XS said:
I've read about many alternatives, but bang for buck still points to using a rebuildable, first runout, Lycoming for most RVs. I applaud the spirit of inovation and pushing the envelope. With the advances by EFII toward FADEC type operation, the current prices of non ethanol MOGAS and the availability of 2nd/3rd owner kits for sale, the price of this diesel package is more than that of a flying VFR RV with a complete EFII system.

Hope this package becomes more affordable and a competitive alternative.
Click to expand...
And bang for buck still points to buying a used, instead of building a new a/c. Yet we still build.

And bang for buck still points to buying used, instead of buying a new engine, Yet Van's still sells new engines at a very good clip.

Got any new info for us?

;-)
 
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