Upgrading DA42 with CD-155 engines

[Colin]

Has Mr. Crosby any interest in shops in the United States using his STC to do the same upgrade? I am a few hundred hours from needing to do it, but I am already trying to figure out what to do. Right now, for the sort of flying I do, a straight replacement makes the most sense, but I do like the idea of adding horsepower for not a lot more money. Hard to know what I would do with it, since I think I am happy enough at the speeds I get (153kts 75% at 9.5k burning 5.4gph), but it would be nice to drop that to 65% and burn even less fuel at the same speed. And running the engines at a lower load seems like it might be good for extending their lives.

[ememic99]

Has Mr. Crosby any interest in shops in the United States using his STC to do the same upgrade? I am a few hundred hours from needing to do it, but I am already trying to figure out what to do. Right now, for the sort of flying I do, a straight replacement makes the most sense, but I do like the idea of adding horsepower for not a lot more money. Hard to know what I would do with it, since I think I am happy enough at the speeds I get (153kts 75% at 9.5k burning 5.4gph), but it would be nice to drop that to 65% and burn even less fuel at the same speed. And running the engines at a lower load seems like it might be good for extending their lives.

I don't know current status of FAA STC but I remember it was announced it would follow (it was 3 years ago) so I guess it has been issued since. If that's the case then he certainly has the interest on getting US shops on board.

For CD-135 getting 153 KTAS at 75% at 9500 ft shows 5.4 GPH but actually it's a bit more - it's more like 5.7 GPH, exactly like stated in POH - I confirmed it accross 500 flight hours and many refuelings.

[Colin]

Your data is higher resolution than mine. I never fly more than five hours and the difference would be 1.5 gallons at the end of the flight. I seems to have ramp personnel that overfill by that much and it is leaking onto the ramp.

How might one reach Mr. Crosby online, do you know?

[ememic99]

How might one reach Mr. Crosby online, do you know?

He shared once his contact here on forum so I don't think it's a problem if I do it again crosbyjohnr@gmail.com

[farleymike]

Hi Colin,

Premier Aircraft Service at KFXE has authorization to do the CD-155 conversion with the scimitar props.

mike

[Colin]

Mike,

Thanks for the info. That's great. I haven't landed yet in Florida, either.

[CFIDave]

Now somebody needs to create a CD-170 conversion for the DA42 TDI, with 170 rather than 155 hp per engine. I'm guessing that Continental turned up the turbo boost further via a software change, much like Austro Engine did with the AE300 to create the AE330. It would be interesting to see how a CD-170 DA42 would perform compared to to a heavier but more aerodynamic DA42-VI with similar horsepower Austros.

Piper recently announced the CD-170 engine for its Seminole trainer:
https://www.aopa.org/news-and-media/all ... d-seminole

[ememic99]

I don’t think it would be good setup - DA42’s fuel tanks are too small and drag would start to overtake benefits of excessive power.

[CFIDave]

I don’t think it would be good setup - DA42’s fuel tanks are too small and drag would start to overtake benefits of excessive power.

Almost all DA42s (TDI/NG/-VI) have aux fuel tanks installed for a total of 76 gallons, and a CD-170 would have about the same fuel burn as the AE300 of the DA42 NG/-VI. (I flew my -VI across the north Atlantic without any ferry tanks needed).

The "excessive power" of CD-170s would likely provide an improved climb rate at lower altitudes (I'm guessing CD-170s would have a lower turbo critical altitude than a CD-135 or CD-155 with the same turbo), and the CD-170 would provide an additional safety margin for climbing with engine loss/OEI. I agree that a CD-170 DA42 might not be much faster than a CD-155 DA42 without "dash six"-like aerodynamic improvements to reduce drag.

BTW, I went back and found where Diamond claimed the new "scimitar" blade propeller of the DA42-VI contributed 3 knots speed increase over the NG, so I imagine it has the same effect on the CD-155 upgrade with similar props.

DA42-VI Improvements.pdf

(519.2 KiB) Downloaded 153 times

[TimS]

I would like to see a -VI with aluminum engines.
Either have AE300 change to the new Benz aluminum block or the CD-170.
That would be a fast and light plane.

Tim