Mike S
Senior Curmudgeon
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Read all about it here. http://www.vansairforce.net/articles/ImagesInForums/images.htm
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Subaru diesel EE20 aircraft RV-7
- Thread starter Syncrogreg
- Start date
It is not an attachment, you host the photos on a site devoted to such, then you insert a link to the hosting site.
Read all about it here. http://www.vansairforce.net/articles/ImagesInForums/images.htm
ee20 on LH-10 elipse in france
i've been looking to do the same engine on a velocity SE. contacted the guy in TN that sells the engines, he put me in touch with this guy from france who has already done a conversion.
311 Lbs., flight ready.
150hp stock- he's limited because of the shaft system on his plane.
4.2 gph at full power
2.6 gph at econ. cruise.
would send you photos of the engine install.. but don't see a way to attach them on here???
as for the direct drive system... take a close look at raptor aircraft on facebook. peter mueller & his team have come up with an option that is simply BRILLIANT! simple, light weight, durable. their device is incorporated in with a belt drive, but it's not dependant on their being a belt drive.
their rubber device operates as a torque pulse / vibration 'dampener'. could easily be used in-line, direct drive with no pulley system.
https://www.facebook.com/raptoraircraft/home
i've been looking to do the same engine on a velocity SE. contacted the guy in TN that sells the engines, he put me in touch with this guy from france who has already done a conversion.
311 Lbs., flight ready.
150hp stock- he's limited because of the shaft system on his plane.
4.2 gph at full power
2.6 gph at econ. cruise.
would send you photos of the engine install.. but don't see a way to attach them on here???
as for the direct drive system... take a close look at raptor aircraft on facebook. peter mueller & his team have come up with an option that is simply BRILLIANT! simple, light weight, durable. their device is incorporated in with a belt drive, but it's not dependant on their being a belt drive.
their rubber device operates as a torque pulse / vibration 'dampener'. could easily be used in-line, direct drive with no pulley system.
https://www.facebook.com/raptoraircraft/home
fuel weight.
added bonus? you can run off-road diesel #2. after all, the sky doesn't have road tax. so why pay it if it's not required? $1.60 per gallon. take THAT avgas.
added bonus? you can run off-road diesel #2. after all, the sky doesn't have road tax. so why pay it if it's not required? $1.60 per gallon. take THAT avgas.
Got a better link? Can't find anything on the site other than a conventional belt drive.
BillL
Well Known Member
rv7charlie
Well Known Member
I'm all for alternative engines, & like the idea of diesel power. But the numbers need to be at least somewhat like real.
4.5 gph at full power would be somewhere around 34 lbs per hr. If the engine is really making 150 hp, that would be 34/150= ~0.23 lbs per hp per hr. That's better than the most efficient diesel ever built. By quite a bit.
http://newatlas.com/go/3263/
So, is he using more fuel, or making less power?
(I too would like to see the direct drive system mentioned, hopefully somewhere other than facebook.)
Charlie
4.5 gph at full power would be somewhere around 34 lbs per hr. If the engine is really making 150 hp, that would be 34/150= ~0.23 lbs per hp per hr. That's better than the most efficient diesel ever built. By quite a bit.
http://newatlas.com/go/3263/
So, is he using more fuel, or making less power?
(I too would like to see the direct drive system mentioned, hopefully somewhere other than facebook.)
Charlie
Tomcat RV4
Well Known Member
A big second shoutout for Ross a SDS,on electrics ,BUT ESPECIALLY on help with cooling!
Weights and BSFC
Hi Guys,
If you would like some weights for this engine, here are the numbers I measured for a 2013 model I stripped:
Component Weights as measured from a 2013 EE20 diesel
All weights presented in lbs
Total As Delivered 437.6 Included emission system, accessories, turbo, DMF but no starter or ECU
EGR Cooler 5.64
Turbo outlet to intercooler pipe 1.82
Intake manifold with throttle body and EGR 13.2
Throttle body intake pipe 0.78
Alternator belt 0.45
Alternator 13.44
Alternator /aircon bracket 0.35
Pipe A 0.44
Pipe B 0.5
Aircon pipe 0.43
Alternator cable 0.68
Aircon pump 9.76
Pipe C 0.81
Bracket A 0.4
Turbo oil line A 0.4
Left lower engine mount 2.86
Right lower engine mount 3.18
Exhaust/Turbo/DPF 59.8
ECU plug bracket 0.41
ECU harness female plug 1.06
Clutch pressure plate 11.48
Clutch friction disc 3.86
Lower left coolant pipe 0.14
131.89
DMF (without friction disc or pressure plate) 31.04
Flywheel crank bolts 0.46
VF57 RHV4 turbocharger complete with small shields and actuator 19.94
vacuum pump 1.84
Turbo water inlet line 0.27
Starter motor 10.36
Total Stripped Weight 274.67 Engine and fuel system but without emissions, intake manifold, DMF, turbo, ECU, alternator, electrical etc.
The marcotte direct drive weighed 30lbs
I see the key to making this a success being the use of much lighter flywheel and ditching the heavy DMF and using a wood core composite prop such as an MT that can handle the impulse loads. This is what is done on the SMA diesel. The Continental 2.0 diesel needs the DMF as it is still running through a gearbox. It would also be beneficial (and in my eyes possible) to trim the weight of the direct drive mount. The marcotte unit is designed for applications of over 800hp, so it's a bit of overkill in this situation. I think there is also room for improvement weight wise by reviewing the way the timing chain cover and accessory belt is set up. The current configuration seems beastly heavy for our application.
As far as BSFC, I used numbers from VW 2.0L diesel, which should be very representative of the Subaru. The BSFC chart may be found below. Regarding power available, you can attain 135hp at a reasonable takeoff RPM (2750) with the stock boost configuration. Cruise at 99hp or 66% power resulted in a calculated 5.68gph consumption and 150kt cruise speed for an RV-7 (assuming cooling drag is the same for an air cooled engine). If I remember correctly (I can't find this in my notes) this 66% power setting was the equivalent of the Outback Diesel car running at 90-100mph.
Further development on this unit at my end is on hold until I have this RV-7 complete (it will have an IO360MIB for now). Tail and wings finished, and about to flip the canoe.
I hope this helps.
Tom.
Hi Guys,
If you would like some weights for this engine, here are the numbers I measured for a 2013 model I stripped:
Component Weights as measured from a 2013 EE20 diesel
All weights presented in lbs
Total As Delivered 437.6 Included emission system, accessories, turbo, DMF but no starter or ECU
EGR Cooler 5.64
Turbo outlet to intercooler pipe 1.82
Intake manifold with throttle body and EGR 13.2
Throttle body intake pipe 0.78
Alternator belt 0.45
Alternator 13.44
Alternator /aircon bracket 0.35
Pipe A 0.44
Pipe B 0.5
Aircon pipe 0.43
Alternator cable 0.68
Aircon pump 9.76
Pipe C 0.81
Bracket A 0.4
Turbo oil line A 0.4
Left lower engine mount 2.86
Right lower engine mount 3.18
Exhaust/Turbo/DPF 59.8
ECU plug bracket 0.41
ECU harness female plug 1.06
Clutch pressure plate 11.48
Clutch friction disc 3.86
Lower left coolant pipe 0.14
131.89
DMF (without friction disc or pressure plate) 31.04
Flywheel crank bolts 0.46
VF57 RHV4 turbocharger complete with small shields and actuator 19.94
vacuum pump 1.84
Turbo water inlet line 0.27
Starter motor 10.36
Total Stripped Weight 274.67 Engine and fuel system but without emissions, intake manifold, DMF, turbo, ECU, alternator, electrical etc.
The marcotte direct drive weighed 30lbs
I see the key to making this a success being the use of much lighter flywheel and ditching the heavy DMF and using a wood core composite prop such as an MT that can handle the impulse loads. This is what is done on the SMA diesel. The Continental 2.0 diesel needs the DMF as it is still running through a gearbox. It would also be beneficial (and in my eyes possible) to trim the weight of the direct drive mount. The marcotte unit is designed for applications of over 800hp, so it's a bit of overkill in this situation. I think there is also room for improvement weight wise by reviewing the way the timing chain cover and accessory belt is set up. The current configuration seems beastly heavy for our application.
As far as BSFC, I used numbers from VW 2.0L diesel, which should be very representative of the Subaru. The BSFC chart may be found below. Regarding power available, you can attain 135hp at a reasonable takeoff RPM (2750) with the stock boost configuration. Cruise at 99hp or 66% power resulted in a calculated 5.68gph consumption and 150kt cruise speed for an RV-7 (assuming cooling drag is the same for an air cooled engine). If I remember correctly (I can't find this in my notes) this 66% power setting was the equivalent of the Outback Diesel car running at 90-100mph.
Further development on this unit at my end is on hold until I have this RV-7 complete (it will have an IO360MIB for now). Tail and wings finished, and about to flip the canoe.
I hope this helps.
Tom.
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No worries Ross. I just wish I had the time on my hands to finish the EE20 build. You could have warned me that just building this aircraft from the standard kit was going to be such a massive undertaking!!! Then again... I think you may have and my overly ambitious nature may have brushed it aside. It's the over analysing and constant desire for perfection that gets in the way!
T.
T.
The dual mass aspect of a DMF (Dual Mass Flywheel) brings an additional inertia to the system, which has an effect on some natural frequency or another. However, at the fundamental level the DMF is a low stiffness soft element.
It might be a major mistake to assume you can run this diesel with a prop bolted to the end of the crank, and assume there will be no torsional issues. We're talking old knowledge here; it's why pendulum absorbers were added to Lycoming and Continental cranks.
(BTW, I have not seen an SMA crank. Anybody know if it has pendulums?)
Remember, a resonant period runs crank stress way up. My guess is that the Fuji engineers already pared the crank down to what they felt was an absolute minimum strength given the careful torsional tuning possible in the car. Given the broken cranks out there, there certainly isn't any great excess. I doubt it will handle any significant resonant period for long. Only way to know for sure is to do the math, an/or strain gauge the shaft.
As for the Marcotte, the typical "pin and bushing" flywheel-to-drive connection is not nearly soft enough. Ross will tell you his Marcotte/gas Sube resonates quite badly at an RPM in the teens. Given the same coupler, gearbox, and prop, the diesel will hammer even harder.
Either way, up-front attention to torsional issues would make it a lot less like a dice roll. This is 2016. Isn't it time to bring a little engineering to the game?
Sheesh.
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Hi Dan. Ross is correct in that the the unit is direct drive and has no gears at all, just a massive pair of bearings (TRB if I remember correctly). I would not be coupled directly either. The clutch friction disc is currently connected directly to the Marcotte spline, and the friction disc face will be bolted directly to the flywheel through the existing rivet holes in the friction disc and into corresponding holes drilled into the flywheel. The friction disc is like most friction discs in that it has a set of springs anyway. This is used primarily in this application for negating any misalignment issues between the crank and the Marcotte shaft, but will also help to distribute the combustion impulse loads over a longer time period. I fully realize that torsional vibration testing is an absolute must for this setup, given that calculating any TV issues is a highly complex task beyond my modeling capability. I'm also aware of the history of the crankshafts and the multiple iterations to address the prior issue, and from the research I have completed, the latest versions have been without fault. In addition I spoke with the engineer many times at MT who developed the propellers for the other diesel applications, and they are extremely confident of the propeller they have specified for the EE20 on an RV-7. It is essentially the three blade O-320 setup with an 0-360 bolt/flanges for the higher impulse loads. I'll upload a picture of the setup on the Marcotte when I get home.
I just hope someone finishes developing this before me because I've been so slow!
Tom.
I just hope someone finishes developing this before me because I've been so slow!
Tom.
Adapting a clutch center is an approach straight from the bad old days of PSRU development. Run it, break, it, "experiment" with another random selection, run it, break it, repeat. It's like trying to write "War and Peace" by arming a million monkeys with a million typewriters.
Coupling diesel engines to driven systems of all kinds is a mature science with the support of an entire industry. The correct torsional coupler is selected based on required performance. Maybe you don't want to study five volumes of Wilson, but even the catalogs have enough selection information to start your project down a reasonable path. If you later need to make a change, the catalog allows a new selection based on specified torque and stiffness data. You can pick something a little stiffer or softer, and know what you changed.
Take some time and look around.
Centaflex offers excellent catalog and online selection help:
http://www.centa.info/?show=downloads&c=us#
The Lovejoy catalog includes pages with simplified selection calculations:
file:///C:/Users/wks/Downloads/Torsional2010.pdf
Hi Dan,
Below is a picture of the back side of the Marcotte direct drive housing. The friction disc has 16 rivet holes of approximately 5 to 6mm in diameter (hard to measure until I drill them out) which will be bolted to the flywheel face (so that the pressure plate etc. will not be required). I apologize about the quality of the photo, however you can also see the friction disc springs, which have a second black spring internal to the outer blue spring.
Tom.
Below is a picture of the back side of the Marcotte direct drive housing. The friction disc has 16 rivet holes of approximately 5 to 6mm in diameter (hard to measure until I drill them out) which will be bolted to the flywheel face (so that the pressure plate etc. will not be required). I apologize about the quality of the photo, however you can also see the friction disc springs, which have a second black spring internal to the outer blue spring.
Tom.
Hi Dan. Interesting about the coupling setup. Guy actually steered me away from this path and toward direct bolting of the friction disc to the flywheel, as the springs would take up any potential misalignment. I will take a look further at the links you have provided.
Cheers,
Tom.
Cheers,
Tom.
Bad advice. The ability to accommodate axial, radial, and angular misalignment is a key feature of most engineered couplers. For example, an ordinary Centaflex A will handle 1.5 to 2 mm of radial misalignment. And unlike a clutch center, there is a published spec for it.
If your design requires an input shaft spline, note the availability of clamped spline hubs, designed to eliminate freeplay and fretting.
Model overview, one manufacturer:
http://www.centa.info/data/content/productIntro/280/productindex01-11englisch.pdf
The massive Marcotte bearing support case may be quite a lot heavier than necessary. The thrust and moments are not huge, unless you plan on really, really hard acro. You can easily quantify the prop moment:
M = I x Q x B
where
M = propeller moment in ft-lbs
I = prop mass moment of inertia in slugs ft^2
Q = shaft rotation rate in radians per second
B = pitch or yaw rate in radians per second
Propeller mass moment of inertia is determined with 2 lengths of safety wire and a stopwatch ("bifillar suspension"), easily done in the home shop. To convert RPM to radians per second, multiply by 0.10472. Use 6.28 radians per second for pitch/yaw, a fairly radical assumption. With moment in hand, you can pick bearings, shaft size, and required case strength.
For reference, the magnesium nose case used on the M14 is very light, and handles loads way beyond anything you'll generate with this little diesel.
The nose case bearing support idea for an auto conversion has been around a while. Here is an Arden Hjelle design, the aluminum block Olds as used in Steve Wittman's Tailwind. The open bellhousing proved to be more than strong enough.
An earlier nose case, again Hjelle/Wittman, for the Formula V racer, circa late 60's. It's just a light sheet metal cone welded to end plates.
a good question indeed. I owned a 2Liter peugot diesel (turbo) for 5 years. made reqular trips of 240+ miles with 2 passengers & 200Lbs. of gear running the engine at around 2500 rpm for the ENTiRE trip.
this was HARD driving, interstate driving, so... continuous. steep hills, 4 to 6% grade.
NO break downs.
NO problems- not even MINOR ones.
38 MPG.
but- this has been my experience with EVERY foreign made diesel engine. ESPECIALLY japanese & german made.
so? YES. given subaru's WELL PROVEN history? I'd say he's on the right track.. putting a subie diesel in an aircraft. i look forward to the results
rv7charlie
Well Known Member
The 25% (or 10%, 15%, etc) rumor against auto conversions has attained internet and hangar-flying whackamole status. No matter how many times it's killed (with evidence), it resurfaces somewhere else.
The testing process for auto engines (in the USA, and almost certainly for the rest of the world, too) would make the FAA a/c engine certification requirements look like the old 3rd class medical (if you can fog a mirror & aren't on major drugs, you're good to go).
There was a long article in Contact! mag several years ago, detailing auto engine testing processes. If you read that, you'll realize that problems with auto engines in a/c are almost exclusively due to the systems around the engine, added by the installer or integrator.
Charlie
The testing process for auto engines (in the USA, and almost certainly for the rest of the world, too) would make the FAA a/c engine certification requirements look like the old 3rd class medical (if you can fog a mirror & aren't on major drugs, you're good to go).
There was a long article in Contact! mag several years ago, detailing auto engine testing processes. If you read that, you'll realize that problems with auto engines in a/c are almost exclusively due to the systems around the engine, added by the installer or integrator.
Charlie
This is generally true but some stuff still slips by all this testing and validation- several cases in point: widespread Subaru EE20 crank failures, EJ25 HG failures, EJ25 dropped valve guides, EJ257 improper ECU programming leading to detonation and piston failures, oil pickups falling off EJ engines. Subaru has had more than their share of serious engine, drivetrain, clutch problems than most Japanese OEMs. Their test procedures are not as demanding or robust as Toyota, Honda or GM.
rv7charlie
Well Known Member
Bummer that Subaru has had that many different issues. On the other hand, both Lycoming and Continental (twice) have had crankshaft failure issues in recent years when they tried to 'tweak' already proven designs. Lots of other examples, but "A man hears what he wants to hear, and disregards the rest..."
Unfortunately, that quote applies to both Cert & Uncert devotees, just like it does to the general population.
Charlie
Unfortunately, that quote applies to both Cert & Uncert devotees, just like it does to the general population.
Charlie
