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  #11  
Old 06-26-2017, 07:23 AM
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airguy airguy is offline
 
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Location: Garden City, Tx
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Bill's numbers are just a few knots better than mine, he has apparently done some better work than I have on drag reduction. In my case I don't ever cruise low enough to see 75% power in cruise, except during occasional goofing-off sessions, but yes you can approach Vne at low altitude where the engine can make good power.

At higher altitude in the mid-teens, the lower ambient pressure will put you in the 50%-60% power range and take the edge off the top end of the TAS, I typically cruise at 155 KTAS in the 14k-17k range burning 6.0-6.5 gph. Approaching Vne in cruise at those altitudes is not a problem, but on descent you definitely have to pull back the MAP to keep the airspeed in control.
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Greg Niehues - VAF 2017 dues paid
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N16GN flying! http://websites.expercraft.com/airguy/
Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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  #12  
Old 06-26-2017, 07:34 AM
KatanaPilot KatanaPilot is offline
 
Join Date: Feb 2015
Location: Locust Grove, GA
Posts: 230
Default Boat Anchor

The Thielert/Continental diesel design is based on the Mercedes diesel but uses a purpose built aluminum block. The Austro uses the Mercedes cast iron block and is much heavier. Seems to be more durable too, but Diamond had to beef up structure and increase gross weights to get the useful loads on the diesel DA40's and 42's back up to a reasonable level.

The Continental engine has a TBR, the Austro a TBO. Not sure if either applies to Part 91 and/or the experimental world.

The latest iteration of the Austro has higher power output but I think it's basically the same core engine with a bigger turbo and more boost. Not sure if it will have the same durability or longevity.
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Krea Ellis

Locust Grove, GA
DA20-A1 Katana "Princess Amelia"
RV-7A under construction
RV-10 under construction
2016 Donation made
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  #13  
Old 06-26-2017, 01:24 PM
kgood kgood is offline
 
Join Date: Mar 2009
Location: Boulder City, NV
Posts: 148
Default Here we go...

To answer the OP's question:
Yes, the CD155 would make a great engine for an RV9.

ON this forum you'll get all kinds of reasons why a Lycoming is better, but since you asked, I'll share my experience with the CD155. I now have 412 hours on my CD155 - powered Glasair Sportsman.

Dan is right, the numbers Cessna is quoting work because the CD155 makes full power to 9000', and only tapers off very slowly after that. It is a joy to fly behind.

A few facts: It is much more efficient than a Lycoming, FADEC or otherwise, especially when you consider the whole flight profile. If you'll check Kitplanes June 2015 issue, an apples-to-apples comparison was done between to similarly equipped Sportsman aircraft. Both perform similarly, but the diesel uses 1/3 less fuel. Depending on the mission, the CD155 can pay for itself easily even though the initial cost is higher. See Redbird's Redhawk website. In training scenarios, the savings are substantial. I know most of us don't fly like that, but if we use the plane a fair amount, we'll save.

It is much simpler to fly: Start it like your car. One lever controls everything. Set it for the % power you want, or fuel burn, and leave it there. If you haven't flown one before, you'll be amazed. SO simple. No leaning, no carb heat, no worries about shock cooling, no mixture, no prop control.

Compared to a similarly equipped Lycoming-powered plane, the installed weight of the CD155 will heavier, probably as much as 60-70 lb. Mine was about 90 lb heavier, but as Glasair has developed the installation package, they have reduced the weight. BUT - you can fly as far as your Lyc-powered friends with 60-70 lb less fuel on board, so you haven't lost anything. But when you want to go with a lighter payload and full fuel, you can go forever. I've flown 8 hour legs in my Sportsman with plenty of reserve.

Safety: one of the main reasons I fly Jet A. The fuel is much less volatile than 100LL or Mogas. Too many people are burned after surviving a crash. Diesel or Jet A gives a much better chance for reduced injury...

For now, I think this is all a mute point as far as the RV9 goes, because last I heard, Continental is not willing to sell these engines to homebuilders. The only way we were able to do it with the Sportsman was to make it available through the TWTT program, installed with factory supervision. It's not terribly complicated, but it's certainly not a known quantity like the Lyc is. The only way that we can get one is for Van's, or possibly some customer-assist center, to work with CMI and develop a package to be installed with assistance. We all know that Van's has no interest in doing this. I can't say I blame them, but I bet that some of their overseas customers would be interested, since the savings would be much greater for many of them...

Kurt Goodfellow
RV9 flying since 2008, Wilksch diesel, 560 hours.
Sportsman flying since 2014, CD155 diesel, 412 hours.
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  #14  
Old 06-26-2017, 02:05 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by kgood View Post

A few facts: It is much more efficient than a Lycoming, FADEC or otherwise, especially when you consider the whole flight profile.
You may be behind the times and I'd question your "facts". I'm doubtful that it's much more efficient than a Lycoming with FADEC and programmable EI running LOP. Dave's 10 to 1 CR IO-360 RV4 numbers at 17,500 feet:

145 KTAS on 22 pph.
181 KTAS on 33 pph.

We estimate the BSFC is better than .33 lbs./hp/ hr. running LOP at 2200 rpm. As good or better than what the Austro AE300 claims for their cruise BSFC.

The savvy fliers are running lean on the ground and even in the climb with the EFI/EI when doing cross country work. Some even report running LOP during formation work. LOP drops the CHTs down while burning less fuel.

Several other RV9 fliers here with less sophisticated fuel and ignition setups have posted sub 5 GPH fuel burns at 135-145 KTAS in the past with 235s and 320s running LOP.

Flying school use where the Lyc is near full rich for most of it's life in the pattern, yup, gonna save a lot with a diesel. In cruise with modern electronic controls running LOP, nope, little or no significant savings there with US gas prices. In Europe, a different story of course.
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Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 414.3 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 06-26-2017 at 03:47 PM.
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  #15  
Old 06-26-2017, 02:46 PM
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DanH DanH is offline
 
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Location: 08A
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Given time, we'll see CD155's in kit aircraft. Continental is just being cautious, as they have cubic dollars tied up in the program, and it's doing well on the certified side. In comparison, EAB is the Wild, Wild West....rugged individualists and all that rot
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  #16  
Old 06-30-2017, 08:46 AM
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Av8torTom Av8torTom is offline
 
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Location: Yardley, PA
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Default Nervous

While it's an interesting idea, liquid cooled engines make me nervous (apologies to all you Rotax drivers out there). I think suitable lead free AV gas replacements are on the horizon.
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  #17  
Old 07-02-2017, 06:41 AM
penguin penguin is offline
 
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Location: England
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Why would you be nervous about a liquid cooled engine? How many aircooled cars are produced today?

Back to the Conteinental/Technify engine, the engine will be significantly heavier than an (I)O-320 or 360, I would guess 50lb, may be more. Now go look at the servicing requirements. Look at the component replacements required every 300 or 600 hours. On new engines the gearboxes are now 1200 hours (used to be 300), but there are other components that need to be changed, alternators, rail pressure control valves, HP and LP fuel pumps, and so on. Sure not required on an experimental, but ... The next question is getting Continental to sell you a motor, replacement motors sell for around Euro 35K, but they are only available from the factory and usually not to individuals. Spares are only available to Technify service centres, as are the service tools - for example to Canbus interface tool to interrogate the FADEC.

The Austro engine is heavier again - as a previous post said it has an iron block - now look at the component replacement schedule, particularly for the 180hp engine. How does a new cylinder head every 300 hours sound? Sounds expensive to me!! That number will increase as the engine accumulates time in service but ...

Right now both these manufacturers are concentrating on certified aircraft and don't seem very interested in selling to the experimental market (except the Glastar program). At first sight may seem like a reasonable option, but I think you will be $10 or 20K out of pocket on the initial install and possibly another $10K out of pocket after 1000 hours thereafter due to component replacements. Reduced fuel burn is not going to make up that difference.

Pete
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  #18  
Old 07-02-2017, 09:21 AM
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rv6ejguy rv6ejguy is offline
 
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Wow, very interesting. Thanks Penguin for bringing those details to light. That information always seems to be hidden away in the servicing manuals of aero diesels. Naturally, these things are rarely mentioned by the diesel advocates.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW- 414.3 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 07-02-2017 at 09:29 AM.
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  #19  
Old 07-02-2017, 10:58 AM
rv7charlie rv7charlie is offline
 
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Quote:
Originally Posted by rv6ejguy View Post
You may be behind the times and I'd question your "facts". I'm doubtful that it's much more efficient than a Lycoming with FADEC and programmable EI running LOP. Dave's 10 to 1 CR IO-360 RV4 numbers at 17,500 feet:

145 KTAS on 22 pph.
181 KTAS on 33 pph.

We estimate the BSFC is better than .33 lbs./hp/ hr. running LOP at 2200 rpm. As good or better than what the Austro AE300 claims for their cruise BSFC.

snip

Flying school use where the Lyc is near full rich for most of it's life in the pattern, yup, gonna save a lot with a diesel. In cruise with modern electronic controls running LOP, nope, little or no significant savings there with US gas prices. In Europe, a different story of course.
How are you estimating the BSFC? Are you accounting for the greatly reduced drag at that altitude?

Numbers quoted at nosebleed altitudes are meaningless to me, and I suspect to 90%+ of other RV drivers. We just don't go there. I know that electronic engine control is more efficient than tractor ignitions and dribble mechanisms, but 10-1 compression is still a lot less than 17-1 (or higher). What would the turbo-diesels being discussed here look like at 17,000 feet?

Charlie
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  #20  
Old 07-02-2017, 01:11 PM
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airguy airguy is offline
 
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Quote:
Originally Posted by rv7charlie View Post
Numbers quoted at nosebleed altitudes are meaningless to me, and I suspect to 90%+ of other RV drivers. We just don't go there.

I think it probably happens quite a bit more than you suspect - speaking for myself I know that about 2/3 of all my flight hours in my 9A are above 15,000'. Granted, I do more lengthy cross-country trips than most, but the airfoil on the 9 just gets so darn happy up there. I flight plan 150 KTAS on 6.0 gph in the upper teens, it's a great place to cruise.
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N16GN flying! http://websites.expercraft.com/airguy/
Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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