Not sure if it has been mentioned in some other thread, but EPS Graflight V8 has started certification testing with the FAA in 2019.
A very good source in Germany told me that EPS still owes Bosch $3 million of the $15 million cost to develop the fuel injection system. Bosch has suspended delivering to EPS until they are paid. EPS doesn’t have the funds and has suspended development and certification.
The main market for aviation diesel engines is in developing countries (Africa, China, Indonesia, Papua New Guniea) where avgas averages about $15.00 a gallon, and Jet A runs from $2.00 – $4.00 a gallon. A diesel only uses about 70% as many gallons per hour to get the same power output. So and air taxi operator, safari transportation user, etc, flying a Cessna 206 for 500 hours a year that was burning 14 gallons per hour ($210 per hour fuel cost) who can switch to 11 gallons an hour at $4.00 or less ($44.00 or less fuel cost per hour), can save $83,000 per year on fuel by switching to diesel. That can pay for a lot of new engine installation costs.
But the EPS engine is too heavy for a Cessna 206.
By the way, the scuttlebutt on the street from a very knowledgeable source is that EPS has run out of money, still owes Bosch $3 million of their $15 million charge to develop the fuel injection system and software, and has suspended operations. Bosch won’t ship them any parts until EPS pays up. Who would invest new dollars in that engine? It will only be suitable for heavier airplanes, of which there aren’t any begging for diesel.
Agreed; it doesn’t add up.
The retrofit market for diesels doesn’t seem to have gone anywhere and the vendors just don’t seem to get the reason why: only very high hour operators will have any chance of recovering the higher installation cost, via the lower fuel cost. I say “higher” because this has to be seen against the overhaul or replacement cost of the existing engine.
And every retrofit diesel option is priced well above the existing engine option. Why? Well, they want to make money, but they also box themselves in because their only customers will be high hour operators.
And guess what the high hour operators (mostly ATPL schools) do?
They buy one of these, which already comes with a diesel engine, and is a proven package
Let’s talk about the weight first. Wikipedia says "The 4.3-liter, 350-horsepower engine will weigh 30 to 50 lb (14 to 23 kg) more than comparable Lycoming TIO-540-AE2A (595 lb (270 kg) dry, from $94,300) or Continental TSIO-550-E (498.4 lb (226.1 kg) dry, from $72,400) and it will cost 30 percent more.
Note that the dry weight is 30-50 pounds more than the engines it may replace, meaning about 640 pounds. Now add in the liquid coolant, radiator and pump for the liquid coolant, and you are at around 670 pounds. What Cessna 206 owner will replace a 500 pound engine with 670 pounds hanging on the nose.
Note also the very loose description of the cost, implying it may cost around $125,000. However, at this year’s Oshkosh meeting, the rep from EPS was bragging that EPS has spent $60,000,000 on development so far, and the engine is far from certification. $15 million of that cost went just to Bosch to develop the fuel injection. Figure the investors are looking for at least 8% a year return on this risky investment. That’s almost $5,000,000 a year profit they will seek. Divide that number by 100 engines per year, and you get $50,000 per engine just to pay the investors, without any actual return of capital.
They also talk about 3,000 hours TBO. But they don’t want to mention that the engine has gear reduction. Such gears usually need to be replaced between 300 and 500 hours. What does it cost to remove the propellor and gear housing, purchase new gears and pay for the labor?
They also will only talk about propeller RPM, and never mention engine RPM. To get 300 hp out of that tiny displacement (182.5 cubic inches), the engine will have to be run at racing speeds. Will it really last 3,000 hours TBO?
Interesting about the Yak-152. The same plane can be purchased (if it ever enters production) with a 9 cylinder radial or a V-12 
Who wouldn’t want one – or two In the west, where the V-12 diesel is envisioned, it has to compete with the similar category aircraft Grob 120 TP with a 450 HP turbine, and this doesn’t leave the V12 much of a chance IMO considering the Russians want the radial engine.
It’s a little heavy, but would probably be a nice fit for some of the old fire breathing twins out there, like 421’s, Commander 680FP, 685’s, Queen Air’s. Even the Aerostar or the 414’s etc could probably benefit from it, but might be just too heavy.
Silvaire wrote:
A 500 HP heavy fuel engine seems to me better suited to low level fixed wing utility aircraft.
Yes. That’s why I mentioned Ag aircraft / drones in an earlier post. I could see this thing being perfect for a crop-spraying drone.
Peter wrote:
My guess is that customers are cautious. Certification does not verify long term reliability. For example FAA certification involves something like 150hrs on a dyno (I have the details somewhere).
I am not sure how long it takes for a completely new engine, but for a design change under STC it is 150 hours indeed, we at LKBU have just completed such a test for a Walter 6-cylinder engine. The test itself was unremarkable (except that it took a bowserful of fuel to conduct), it was the subsequent engine disassembly, inspection and measurement that our CAA took very seriously and sent representatives to witness it.
