What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Diesel

jssaylor2007

jssaylor2007

Active Member
I know Glasair is running the diesel apparently trouble free, my question is, how many diesel RVs to we have out there?
 
Far as I know, there are (or have been) 6 RV's in Europe with Wilksch diesels, along with my RV9 here in the US. The only other diesel RV I'm aware of is Scott Flandermayer's RV10 with Continental CD230 diesel.

I have 800 hours on my Glasair Sportsman diesel, with excellent service. No issues at all.

Kurt Goodfellow
RV9 / Wilksch diesel 600 hours. Now installing a JP01 diesel.
Glasair Sportsman / Cont CD155 diesel 800 hours.
Cessna 180 / CKT diesel, currently building.
 
Kurt - as a fellow Sportsman owner (O-360-powered) I'm curious to know your performance numbers so I might contrast them with mine. Would you mind sharing, please?
 
Ken Krueger did a test between the O-360 and diesel Sportsman, published in Kitplanes. You can find it here:https://www.kitplanes.com/gas-vs-diesel/

He was pretty thorough; you'll notice that as altitude increases, the 155 hp diesel comes closer to matching the 180 hp Lycoming performance. I've found that at around 5,000'DA, the diesel matches the Lyc, and performs better with altitude above that.

Not readily apparent in the article was that all of our testing was at 75% power for the diesel, and the Lyc Sportsman at WOT, IIRC. To match the Lyc's cruise speed at almost any cruise altitude, all that's needed is a slight push on the power lever, with the fuel burn still significantly less than the Lyc.

I wouldn't mind having one of the new CD170's in my Sportsman. It would definitely take up that lower altitude performance delta.

Kurt
 
Retaining the horsepower in the higher altitudes is very attractive - but not attractive enough to swallow the +110 pound weight and +$20k cost adders.
 
airguy said:
Retaining the horsepower in the higher altitudes is very attractive - but not attractive enough to swallow the +110 pound weight and +$20k cost adders.
Click to expand...

The avgas Sportsman in the test was an exceptionally light one, and my Sportsman, as the first installation, ended up 20-30 lb heavier than the later factory ones. The actual weight penalty is more like 80-90 lb.

You can put 90 lb less fuel in the diesel and still fly further than the avgas plane, all else being equal. So the added weight is not a penalty.

The fuel savings over the life of the engine pays for itself, and then some, even here in the US.

That said, it is generally agreed that here in the US, there's no major draw to buy a diesel. There are diesel fans, like myself, that appreciate the benefits, but most are perfectly content with traditional engines. That's fine. However, there are many countries outside the US where aerodiesels provide huge savings and better access to flying where Avgas is not available or prohibitively expensive.

Kurt
 
Kurt - your comment about the fuel savings paying for the engine is interesting to me. Are you basing these numbers on 'road diesel' or 'farm/commercial diesel' or Jet-A?

I've looked at Glasair's current price list which shows a $50K up-charge to add the diesel in the Two Weeks to Taxi program. It's not available to homebuilders. Continental says the engine has a 2100 hour Time Between Replacement (not overhaul). I don't know what the cost delta is between acquiring a new CD-155 versus overhauling an IO-360. Perhaps you'd share your cost calculations, please?

I would love to have an aero-diesel but have a hard time making the numbers work. What am I missing? I admit my personal numbers are biased as a result of burning mogas in our O-360-powered Sportsman, but even when I run numbers based on 100LL prices I'm still not seeing the payback.. I've got to be missing something in my math...
 
Sportsman

So how is the sportsman vs something like a 172? From my outside perspective it looks like a 172/182 that you can do your own maintenance on.
 
kgood said:
Ken Krueger did a test between the O-360 and diesel Sportsman, published in Kitplanes. You can find it here:https://www.kitplanes.com/gas-vs-diesel/

He was pretty thorough; you'll notice that as altitude increases, the 155 hp diesel comes closer to matching the 180 hp Lycoming performance. I've found that at around 5,000'DA, the diesel matches the Lyc, and performs better with altitude above that.

Not readily apparent in the article was that all of our testing was at 75% power for the diesel, and the Lyc Sportsman at WOT, IIRC. To match the Lyc's cruise speed at almost any cruise altitude, all that's needed is a slight push on the power lever, with the fuel burn still significantly less than the Lyc.

I wouldn't mind having one of the new CD170's in my Sportsman. It would definitely take up that lower altitude performance delta.

Kurt
Click to expand...

Kurt, I am reading the article but the first thing that caught my attention were your plane had smaller wheels and pants. How was this accounted for in the comparison?
 
To be perfectly honest, I think a $50K premium for the diesel is too much to make it pencil in the US right now. I have no idea why Glasair would charge that much. IMO the difference should be no more than $20-25K.

In the article, Ken's math is about as good as anyone else's. He shows $22.95/hr fuel savings over the O-360, which would amount to $48,195 over 2100 hours, based on Jet-A vs Avgas pricing. I don't know how much Mogas is, but off-road bulk diesel is around $1.80/gal right now. That might pencil out...

I'm not sure what an O-360 overhaul costs, with new accessories, but I'm sure you do. I'm sure there's some value in having a NEW engine vs a rebuilt one. I have never done it yet, but I'm told the cost for a replacement CD155 is around $40K, with all new accessories included. There's lots of ways to do the math, but the diesel price premium needs come down in order for the the diesel to pencil against the gas. The only way for that to happen is sell more engines. A vicious circle...

Kurt
 
BillL said:
Kurt, I am reading the article but the first thing that caught my attention were your plane had smaller wheels and pants. How was this accounted for in the comparison?
Click to expand...

You'll need to ask Ken that. I now have 8:50x6 mains, no pants; It cost me 4kts in cruise. Note also that the gas plane had wing strut fairings top and bottom; mine did not; still doesn't. I'm not sure how much speed those fairings add...

My plane was 110 lb heavier as well. As I mentioned in my earlier post, to be a fair comparison, I should have left 110 lb out, which still would have given me greater range. Am I thinking wrong here?
 
jssaylor2007 said:
So how is the sportsman vs something like a 172? From my outside perspective it looks like a 172/182 that you can do your own maintenance on.
Click to expand...

It's smaller inside than a 172/182. But it has a higher useful load than a 172 and some 182's. It's a good two-place with loads of luggage space and capacity. And a huge baggage door. OR it's a comfortable four place for shorter hauls, since with 4 on board, luggage space is pretty limited. Rear passengers are comfortable, with plenty of leg room, but facing rearward... That large baggage door makes for easy entry and exit for the pax.

It's much faster than a 172 and as fast as 182's generally speaking.

For example, I flew the diesel Sportsman side by side cross country with a 180 hp 172. I had to bring my power setting back to 60-63% burning 4.8 gph to stay at his speed. At my cruise speed, 75%, I pulled away quickly.

Another example: we departed Smiley Creek, ID, loaded with two men, mains full, and all our camping gear, shortly after the departure of a Cessna 182 with 3 on board. We passed him in the climb before reaching pattern altitude. At lower altitudes, I think the 182 would be faster...
 
for all the benefits diesel fuel provides... having seen one of the EU Wilksch powered RV in the UK, it was the ugliest RV seen to date. Yes, the beauty in the eyes of the beholder thing ;)
And watching the take-off, well, didn't make it look more of an RV either...

The savings by the hour of diesel vs Avgas are huge alright. Thing is, most owners only fly their RV a few hours a year, say typically 50-100h. At this rate it takes dozen of years until the benefit really takes grip, at the moment that is.

The real actual benefit of a diesel powered ship is the availability of jet fuel almost everyplace. Example, the Greek islands have been on my radar for many years... almost all of them having Jet-A1 but nil Avgas. Same for northern Canada, Africa, SA, etc...
 
Thanks for sharing your realistic comparisons on overall costs. I agree - the $50K up-charge by Glasair just doesn't work out on my calculator. Gasoline is going to be my flying friend for a while yet, unless I can get a good diesel at a more realistic installed price. Patience, patience...
 
Has anyone put a CD-265 on a RV-10? it runs Jet-A which is what I would love considering how high 100LL can be
 
Last edited:
Scott Flandermeyer has had one in his -10 for some time and posts regularly here. There are several threads if you search: https://vansairforce.com/community/showthread.php?t=158832&highlight=diesel

This is being done with Continental which is very encouraging for those who will follow.

Continental has made many improvements and changes to the engine from its original SMA roots where it had serious case fretting issues and low altitude and temperature restrictions.
 
Last edited:
rv6ejguy said:
Scott Flandermeyer has had one in his -10 for some time and posts regularly here. There are several threads if you search: https://vansairforce.com/community/showthread.php?t=158832&highlight=diesel

This is being done with Continental which is very encouraging for those who will follow.

Continental has made many improvements and changes to the engine from its original SMA roots where it had serious case fretting issues and low altitude and temperature restrictions.
Click to expand...
Seems like a really good option for me, i just cant make my self do this kit if I have to put fly 100LL
 
You must log in or register to reply here.
Back
Top