Rv10TDI returned to flight

[rv6ejguy]

Originally Posted by BobTurner

Remember that diesel fuel is about 10% heavier per gal, and has about 10% more energy per gal, than Avgas. Honestly, I thought it should do a little better than that.

Yup and on a pph basis, pretty much a wash in cruise. The climb segment would see the biggest delta in fuel flows as the Lyc is pretty thirsty ROP here. RVs climb pretty fast though so you're not there too long unless you're climbing really high.

[KiloWhiskey1]

10gal/hr at 177kts sounds good to me. Interested to see speeds up higher.

[Canadian_JOY]

Originally Posted by Flandy10

First—-I haven’t spent any recent time in a four cylinder Lycoming or a six cylinder for that matter so…..

Initial idle can feel a little rough when the engine is cold at 800rpm (not terrible) and there is a band between 900 and 1000 that I avoid (only have 11 hrs on this one, but the TD 300 was similar), above that it seems pretty smooth to me. It runs at a constant 2200 rpm from takeoff till landing power reduction.

As for performance, the cowling I have is just what I was using with the TD300 and it was more oil temperature sensitive 235F in climb and around 205F in cruise. Both were with cowl flaps open year round. Initially, this one cools much better. Climb and cruise with cowl flaps closed is 195F and 185F. CHTs are not above 335F climb and 300F cruise with a 392F red line. So some aerodynamic improvements are in the works.

Thanks for this feedback. I don't think many of us feel comfortable in a Lycoming idling at 800 RPM as many of them are pretty "chunky" in idle at that low speed. By the same token, a 2200RPM cruise has to feel pretty laid back compared to 2400+ RPM for the Lycoming.

I wanted our aircraft to be a diesel but just couldn't swallow the $80K price differential over a Lycoming. Needless to say, I'm living vicariously through you now!

[rv6ejguy]

Originally Posted by KiloWhiskey1

10gal/hr at 177kts sounds good to me. Interested to see speeds up higher.

Any turbocharged aircraft will true faster the higher you go until reaching critical altitude with fuel flows remaining essentially unchanged. Turbos= awesome.

[DanH]

Originally Posted by Auburntsts

Very interesting for sure. Can't wait to read more about it. Besides the specs and performance numbers that everyone wants to know, I'd especially be interested in what's all involved in converting a flying RV-10 with a 540 to this diesel.

It is indeed interesting.

I suspect most builders don't grasp the full extent of this conversion. The link below will take you to a Kitplanes story about the prior installation, the Continental version of the engine.

https://www.danhorton.net/Articles/J...20Of%20Us.docx

BTW, the Continental and SMA versions share a layout, but they are not twins, and they are nothing like a similar avgas 4-cyl.

Originally Posted by Flandy10

As for performance, the cowling I have is just what I was using with the TD300 and it was more oil temperature sensitive 235F in climb and around 205F in cruise. Both were with cowl flaps open year round. Initially, this one cools much better. Climb and cruise with cowl flaps closed is 195F and 185F.

Scott, does this version incorporate the oil-cooled valve seats of the cut-from-billet Continental heads? If not, it may account for the lower oil temperature.

(Photo below, annular grooves for oil circulation. They form a passage when the valve seat, not shown, is shrunk into the head.)
.

[onebounce]

Thanks for the link Dan, fascinating article, hopefully this will lead to an available diesel option, especially for us here in Europe where Avgas is $6 to $7 a gallon and Jet A about $2 to $3 a gallon (although the tax man has an interest in Jet A sales for GA).

Incredible to think of the perseverance and determination that Scott has shown to get this far.

[Flandy10]

Dan,

The CD230 I flew did not have the billet cut heads.

I do not know about the internals of this engine but I believe the head is oil cooled. You can see the oil lines to the heads in the attached photo.

[gregfuess]

Originally Posted by DanH

It is indeed interesting.

I suspect most builders don't grasp the full extent of this conversion. The link below will take you to a Kitplanes story about the prior installation, the Continental version of the engine.

https://www.danhorton.net/Articles/J...20Of%20Us.docx

.

Thanks for this article, a fascinating and inspiring read.

[Goran]

I've just checked the SMA Aero Engines web site. Now they have two engines available, SR305-230E (230hp) & SR305-260E (260hp).

https://www.sma-engines.aero/the-pro...0e-sr305-260e/

Do they have a distributor in USA?

[TS Flightlines]

Having been involved with this project, and both versions of engines, I can say here that this its definitely NOT an easy conversion. We've plumbed both engines and the cabin, and there have been MANY hoses that were built, modified, trashed and started over. HUGE differences from the Continential version to the SMA version. And thats just the plumbing side.

I know that Scott has labored, fought, cussed and maybe had an adult beverage or many with this project. BUT he had the fortitude to see it through. YES its different than most conversions you might see, but he was convinced he was on the right track. Yep, it flys, apparently reliably enough to have a flight to 3J1 to see me--and I suspect many more in the future.

Little things took alot of thought on this project. Engine mount conversion. Exhaust. Oil cooler. Cowling and ducts. Just to name a few that took quite a while to engineer. Then little things that seemingly held up progress.

But, Scott has the plane he wanted, to fullfill the mission he had, and he did it his way.

Proud of you my friend.
Tom