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Rv10TDI returned to flight

Flandy10

Well Known Member
After a VERY LONG year, the task of changing out the prototype TD300 diesel engine for the type certificated SR305 engine is complete.

The factory sent a representative to inspect the installation on Monday and finally on Tuesday…

It came to life…. https://youtu.be/6iXa01u8nqo

First flight was Wednesday…
https://youtu.be/IUJRRmyfz3w

Short first flight-yes. Several other flights were made after making prop and governor adjustments. An alternative engine mapping was also tested.

More testing to come…
 
Scott, congrats on the flight and your patience! Good to see it’s back flying. I’m excited to hear about more details.
 
Scott----PROUD OF YOU---not only for the work, but the persistence to see this through. WE wer pleased to have been a part of this project!

Tom
 
following!

Can't wait for more updates!

I noted that there are a couple of versions of the SR305; are you using the 230 hp or the 260 hp?
 
wow. a lot of work. it seems it could be worth it for the future, but I guess it depends on how much you fly.
 
Congrats Scott, looking forward to more specs as you fly the new engine.

I'm confused with the nomenclature describing this engine. It's been called so many different things over the years. Have they settled on something finally?

You mention re-mapping. Is this version now FADEC controlled or does it still maintain the mechanical injection it had previously?

Thanks
 
This is the 230HP SMAAE SR305-230E. The TD-300 prototype was returned to CMI.

I am thankful to my friends at CMI for the chance to start this project. Covid/economy/changes to the production engine/etc. were slowing progress toward the completion of our agreement, a type certificated production engine. 2020 saw SAFRAN sell the SMA line of engines to the Roder Group in Germany (SMA Aero Engines)and I saw an opportunity. Like CMI, they see the potential in the airframe/engine combination that I do. So I switched manufacturers and as I promised with the TD-300, I will provide data once I have the installation adjusted- both the good and bad. Which hopefully won’t be too long.

The MAIN difference between the SR305 and the CD-265/TD-300 is the SR305 has a computer that controls the ground and flight idles, along with max power. It is not a FADEC system,like the CD-155 or Austral 300 on the Twinstar, as there is a mechanical back-up mode. SMA licensed/sold the SR305-1 information to CMI to produce their engine as they saw fit, hence the visible similarity between the two.
 
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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.
 
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TDI Update

For those that are interested.....

Here are some initial performance numbers from a flight a few days ago.

They are Max Continuous power (230HP =12.5gph), recommend cruise (185HP=10.0gph) and econ cruise(150HP=8.2gph). FF is (as I said before) difficult to read with a turbine meter system due to the engine lift pump is a mechanical piston pump pulling fuel at 66gph in flight. So these FF numbers were calculated using the factory information. I did develop a system that will read it pretty accurately but the computer that translates Marine language to Garmin has a problem right now. I'm not sure if it is worth the complexity and weight because fuel flow on this type engine is a fixed number related to the high pressure pump rack position.

The following was recorded from the GTN650 while flying on autopilot and letting speed stabilize for several minutes at each altitude/power setting. GW about 2600# on this flight

5000ft. Max 169Ktas Rec 160Ktas Econ 145Ktas
7500ft. Max 176Ktas Rec 162Ktas Econ 147Ktas
10000ft. Max 180Ktas Rec 169Ktas Econ 150Ktas
12500ft. Max 184Ktas Rec 177Ktas Econ 158Ktas

Engine is rated at 230HP to 10000Ft and drops off to about 170HP at 20000Ft (its max certified altitude). I don't have an oxygen system yet, so anything higher will come later.
 
Very interesting to see this! I missed it when you first posted it. Keep the information flowing, please!
 
I'm curious to learn about the "seat of the pants" experience. In the automotive world cars are rated on a scale for NVH - noise, vibration and harshness. How does this powerplant combination "feel" as compared to a typical Lycoming? How does it compare with respect to perceived noise and vibration levels? Are there any parts of the power band which just "feel" better?

When I look at those cruise numbers I'm thinking that's a lot of speed on not a lot of fuel. Yes, the RV10 is slippery to start with, but still, these numbers are compelling.
 
When I look at those cruise numbers I'm thinking that's a lot of speed on not a lot of fuel. Yes, the RV10 is slippery to start with, but still, these numbers are compelling.

Looks like about 1 gph less than a 540 running LOP at similar altitudes/ speeds. The non-turbo 540 can't match the high altitude/ high power setting speeds of course.
 
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.
 
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Looks like about 1 gph less than a 540 running LOP at similar altitudes/ speeds. The non-turbo 540 can't match the high altitude/ high power setting speeds of course.

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.
 
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.
 
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!
 
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/Jet-A For The Rest Of Us.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.

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.)
.
 

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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.
 
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.
 

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Not Easy---

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:eek: 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
 
Goran- no US distribution center, they ship from Europe.

The 260E is essentially the same as the 230E with a few internal differences, but with this engine, more HP brings a few issues. More later after I check my facts.

I can’t say THANK YOU enough to Tom for his help on this project. Having top quality hoses made-to-order quickly, was invaluable.

The aircraft was AOG in May waiting on some replacement hoses for the fuel system while someone;) was in the hospital. Now that that situation is successfully resolved:D I can return to flight testing some cooling adjustments. I’ll post an update later in June and will include the install weights.
 
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Weight & Balance

Ok, time to answer the question of weight.

During the research phase of this project, I placed a call to Tule River Aerospace, who was doing the SMA C182 conversions. The before and after weight of the STC was +125lbs and ¾” C.G. change on one particular plane. Not the lightest conversion, but it’s a diesel, so I knew what I was in for. Since mine was never a flying IO540 powered plane, I didn’t have an accurate “before” weight. I figured that, based on other flying Rv-10s, I should have been in the 1700lbs+ EW, which, should have brought the conversion in at about 1850lbs EW.

Well, to my disappointment, it wasn’t. It was closer to 1915lbs. Why so much heavier? Well, I didn’t weigh everything as it went into the airframe and the FWF but I’ve had time to think about it and believe the following is correct: It is a “well primed” structure (don’t start a Primer War with me here), local grounds were not used, sound insulation (some of which has since been removed) in the “tub”, and I made my own cowling out of the original Van’s cowl (some would call it overbuilt and resin rich). Over the four years I had the TD300, mods were made to the cowling, fuel metering system, oil cooler, and the brakes were upgraded (heavier duty) due to the higher residual thrust. So, no it didn’t really get lighter during that time, but it hauled everything I needed and it was a work in progress.

Due to Covid, some engine development issues, and management changes, the CD-265 production was put on hold in 2020 and I returned the prototype to CMI (status is unknown as I haven't talked with them since then). At the same time, Safran sold the SMA engine line to the Roder Group in Germany, so I was able to finally get my “certified” engine. I spent 2021 dealing with Covid supply chain issues while converting to the SMA SR305-230E. I kept better weight records of the parts I used and also tried to find lighter ones along the way but could only do so much. The SR305-230-1 was published at 430lbs dry weight and the -230E is listed at 456lbs dry weight. The TD-300C+ (my prototype engine) was around 441lbs dry weight according to CMI. So, when I weighed the plane again, I wasn’t surprised that it gained weight- over 1950lbs EW. The FWF spreadsheet I created comparing the IO540 to the SR305 put the conversion at 140lbs different. Yes, it is heavy.

So, I have started a weight reduction program:
1- Remove 8.6lbs FF measurement system- Engine computer tells Garmin the FF.
2- Remove 15lbs SafeAir One aux tanks.
3- Remake cowing and ducts to be lighter by 15-20lbs.
4- Lighter weight brakes 5lbs.
5- Remove Concorde Main battery and backup battery system and replace
with EarthX -25lbs.
Total weight savings- 68 lbs. when it’s all done.

Currently flying at 1940lbs EW and 107.87 CG. Aiming for 1895Lbs EW and 107.54 CG.

For an additional data point, I am working with a company in Brazil to install this engine in the Rv-10 for their market. They did get an early CD-265 flying for a short time before 2020 issues stopped it. Their plane weighed in at 1898lbs EW painted with an A/C system and an identically equipped IO540 plane weighed 1778lbs. Converting to the SR305-230E will change the numbers but time will tell.
 
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Really appreciate you publishing all this info. Prototypes and test airframes usually accumulate some "extras" along the way. I did a similar weight reduction program some years after the build taking out development bits and Pb batteries for a loss of 23 pounds.
 
Latest

Thank you to Doug and others for the OSH 22 updates.

Really wanted to have the plane there this year but….

While prepping the plane for the trip up, I found this…:eek:
i-sJ7v99r-L.jpg


There is no MEL relief for this problem... Immediate grounding! Fortunately, I found it at home.

So, its crated for transport to Deland for Overhaul and it leaves on Friday. 5 1/2 week minimum turnaround right now.:(
i-G5f8Tp4-L.jpg



I can see the photos in my posting using MS Edge but not on an iOS device :confused:, so here they are as attachments too.
 

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Scott, as much as I was disappointed when you called about this, I'm REALLY glad that you caught it. I certainly didnt want to read about a good friend of mine that landed in a field without a prop in the middle of America, while on his way to Oshkosh.
Regroup, my friend, it will be ok.
Tom
 
Thank you to Doug and others for the OSH 22 updates.

Really wanted to have the plane there this year but….

While prepping the plane for the trip up, I found this…:eek:
i-sJ7v99r-L.jpg


There is no MEL relief for this problem... Immediate grounding! Fortunately, I found it at home.

So, its crated for transport to Deland for Overhaul and it leaves on Friday. 5 1/2 week minimum turnaround right now.:(
i-G5f8Tp4-L.jpg

Can't see the image - can you upload it with the paper clip?

( https://photos.smugmug.com/photos/i-G5f8Tp4/3/L/i-G5f8Tp4-L.jpg)
 
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