Suzuki V6 "Mini Merlin" for RV-9(A)?

Suzuki V6 "Mini Merlin" for an RV?

Listers...

I'm inclined toward an liquid cooled alternative engine for my RV-9A (tailkit arrived in May). I'm looking for 170 - 180 hp. I've watched this conversion engine scene for about 7 years now. To wit...

Subaru:

1. Jan Egg seems to have abandoned the RV-9[A] due to the excessive weight of his E6 installations (he says otherwise, of course, but I am not about to build an RV-9A with a 1250 lb empty weight) and I have mixed feelings about his front-mounted radiator cooling paradigm, among other things. The only flyers who get true RV performance out of Egg installations are Jan himself and his west-coast associate Robert Paisley. The supercharged 2.5L did surprisingly well in the RVator flyoff but is no longer available. Everybody who pays gets an engine...eventually. I will keep watching developments with Egg. I think the ideal Subaru for an RV-9A would be a gently turbo'd EJ2.2 or 2.5. Jan doesn't offer this. 'Nuff said. http://www.eggenfellneraircraft.com/.

2. NSI has died. They had pretty engines. Really. You could just never actually get one, even if you paid for it. A few were actually delivered for RV's. Tom Welch, you still out there flying your NSI RV-9? Rupert Clarke in Australia?

3. Maxwell Propulsion Systems, Inc http://www.maxwellpropulsion.com/ has taken over the carcass of NSI. They seem very quiet two years on. Anything going on?

4. Crossflow seems to have burned their bridges with the RV community. http://www.crossflow.com/.

Mazda/Wankel/Rotary:

5. The rotary installations have yet to mature, although I am watching closely. At this point they remain mechanically "over my head" due to the lack of a proven firewall forward installation. Tracy Crook soldiers on impressively. http://rotaryaviation.com/. Dave Atkins too. http://www.americanrotaryengine.com/id5.html. I'll be watching the Propelled Engineering website http://www.propelledengineering.com/ closely to see what they come up with. Their planned price of $28K seems ridiculous. I'll be watching Mistral too http://www.mistral-engines.com/ but they will likely cost too much. PowerSport seems dead, with no web site updates in over two years. http://www.powersportaviation.com/. For now the rotary installations seem best left to genuine gear heads.

Chevy:

6. The Belted Air Power Chevy Vortec V6 installation intrigues me, although it is too heavy and Jess Meyers resists the use of the lighter aluminum head option (the CG has been engineered for the heavier, cheaper, cast-iron heads). Their web site is almost never updated http://www.beltedair.com/ and I have found zero BAP flyers active on the web. Last summer Jess was active here, but nothing lately. BAP has been around the RV world for well over ten years now. There should be dozens of happy flyers spreading the news but one never hears from them if they exist. I'd love to see/hear more on this package. I'll be watching.

Diesel/JetA/Kerosene:

7. The Deltahawk may come of age by Y3K. http://www.deltahawkengines.com/.

8. The Theilert seems complex/troublesome and is unavailable anyway. http://www.centurion-engines.com/.

9. The WAM-160 is a pipe dream. Mark Wilksch left the company. The WAM-120 will not meet my hp needs. http://www.wilksch.com/.

Miscellaneous:

10. The Jabiru 5100 is apparently dead. Air cooled anyway, but smooooooth. http://www.usjabiru.com/jabiru_5100.htm.

11. ATP/Innodyne is all talk and two prototypes. I doubt this will ever come to fruition. http://www.innodyn.com/aviation/index_aviation.html.

12. Verner Scarlett 190 hp Radials? Too way out there for me. http://www.flydiver.com/HTML/RadialSpecs.htm.

So...I'd like to dredge up some comments on the Suzuki V6 as an option for an RV. Apparently these (2.5L or 2.7L) engines are gaining some traction with the Titan T-51 crowd. This was pioneered by Dan Hawken in Alberta beginning about three years ago. The Titan factory has actually begun to support the installation. A few are now flying. The 2.7L installation is supposed to be derated to about 175 hp in the aircraft installation. Installed weight is in the low 300's. This would be perfect for an RV, it would seem. I have found no clear, single source of technical information on the package. Mr. Hawken himself is not on the web. I snooped around the Yahoo T-51 list and noticed...surprise...Ross is there and knowledgeable.

Whadyathink of this for an RV, Ross? Is the shape too deep and skinny to fit well on a side-by-side RV firewall? What sort of PSRU is being used? Could it be installed without a P-51-style radiator scoop? Any hints as to the durability of the peripherals? Anyone know of a web link with a summary?

I watched/listened to a few "Mini Merlin" videos from the T-51 Yahoo site and the engine sure sounds sweet...

http://f1.grp.yahoofs.com/v1/MN59Rl...VuzsWbSSk/Mini-Merlin V6/T-51_Mini-Merlin.wmv

http://f1.grp.yahoofs.com/v1/MN59Rs...IRGH-GDJANDvmicHqorI/Windsor Flyby/dennis.wmv

Dan
Chicago
RV-9A Tail Kit

You've compiled a good list there Dan!

I like the Suzuki V-6 idea! Cool videos too! Hadn't seen those before.

If you head towards my direction, I'm just down the road from you...stop by sometime!

Insurance?

Dan,

Not trying to flame your ideas, but you might want to call your favorite agent and see if you can insure a plane like you describe. Sadly this is one of the major items to consider these days and the last I heard in order to get insurance with an alternate engine it must be a firewall forward package such as the Eggy. I suggest you call our friendly RV insurance specialist Jim Pappas and pick his brain.

http://www.pappasinsurance.com/

Best,

Brian...

As you know the insurance issue for conversion engines, like primers wars, canopy types, nose wheels, etc has been well hashed out before. The Suzuki V6 installation, properly done, will probably pass that test. Engine lovers have been actively experimenting in the face of this issue for years. I wouldn't let that stop me for a good engine installation.

Dan

Yep, I'm on all the popular engine forums as I like to keep tabs on our ECUs and help anyone out I can.

I know Dan Hawken quite well (just visited him a couple weeks ago) and we supply the ECUs for the Mini Merlin V6. Dan is a very smart fellow with decades of practical mechanical experience. The drive was designed and built by him. It is a belt unit, robust and well flight proven.

Weight wise, the Suzuki will be similar to an EZ30. Power wise, it has less to offer than the EZ30-R now being supplied by Eggenfellner. Probably the 2.7 puts out around 155hp for takeoff at the rpm typically turned. The V6 is very compact and is a really strong and well designed engine- typical modern Japanese engineering.

Dan has offloaded the Mini Merlin design and drawings to Titan last year who I think now has subcontracted machining and assembly to someone else. Last I heard they were tooling up and hope to fill many orders they have for the kit. Dan was selling all the components required except the engine which can be found locally out of the Vitara.

It is a wonderful sounding engine and gives the T51 much better performance than the original 912S albient with about a 150-180 lb. weight penalty. Probably be fine for a -9 but you'd have to design a mount and cooling system. Would fit under the cowling no problem I think. You might have a problem sourcing the engine kit unless Titan has sold you a T51 however!

We're doing some work on a couple of turbo STI engines now. Hope to have a ECU solution to control the variable cams and tumble valves and drive the factory COP ignition. This would be a powerful and lighter weight alternative with more redrive and possibly mount availability. The turbo allows you to make real hp while keeping rpms low for decent fuel flows. I have no plans to offer a FF package as I'm already too deep in projects myself but this is the engine people should be working on for RV7 and RV8s- 300hp and 300 lb./ft. stock. Derate to 200hp and it will last forever.

For the RV9, the latest atmo EJ25 rated at 173hp could do a good job at close to Lycoming weights if the redrive ratio was selected to allow the engine to spin up to 6000 for takeoff (about 2.2 to 1). I'd expect cruise fuel economy with this setup to be at least 10-15% less than an O-320 but auto fuel could offset this in $ perhaps. 4400 would give you about the same cruise power as an O-320 at 75%.


Turn key, Eggenfellner is the only game in town at present.

Your condensed version of "dream" engines is impressive!

STI ECU

rv6ejguy said:

...We're doing some work on a couple of turbo STI engines now. Hope to have a ECU solution to control the variable cams and tumble valves and drive the factory COP ignition. This would be a powerful and lighter weight alternative with more redrive and possibly mount availability. The turbo allows you to make real hp while keeping rpms low for decent fuel flows. I have no plans to offer a FF package as I'm already too deep in projects myself but this is the engine people should be working on for RV7 and RV8s- 300hp and 300 lb./ft. stock. Derate to 200hp and it will last forever...

Click to expand...

Ross, I know about 25 guys that would be very interested in this. Many have already closed off the oil for the variable cams, so would your solution still work for them? Also, what does the tumble valve do? The turbo sounds very exciting.

Put that in your pipe and smoke it

How about this GM Isuzu V6 installation: http://www.supermarineaircraft.com/Engine.htm

V6 used in 90% replica Mk26 Spitfire. (nice real/fake 6 into 12 tube stacks, must sound nice, can you see your RV with 12 pipes sticking out the cowl! cool )






Large scale pics showing scale
http://www.supermarineaircraft.com/Images/IMG_0178.JPG
http://www.supermarineaircraft.com/Images/P1020266.JPG
http://www.supermarineaircraft.com/Images/P1000071.JPG
http://www.supermarineaircraft.com/Images/Spit-complete03_000.jpg

PS Nice nice right up on the state of alternative engine companies.

rv8ch said:

Ross, I know about 25 guys that would be very interested in this. Many have already closed off the oil for the variable cams, so would your solution still work for them? Also, what does the tumble valve do? The turbo sounds very exciting.

Click to expand...

Hi Ross

I know these guys too, in fact I am one of them. Be very interested to learn more.

And so far my STI is unmodified.

Peter

rv8ch said:

Ross, I know about 25 guys that would be very interested in this.

Click to expand...

26, dont forget me ;-)

The tumble valves on the STI are secondary butterflies in the lower staock intake manifold designed to impart turbulence and higher mixture velocity at low speeds for better fuel economy. The Eggenfellner intake manifold removes this. Not very important for aircraft use where we generally operate over 4000 rpm most of the time.

The variable cam timing has been locked in the high position on the Egg engines as well, again I don't see a detriment to doing this in this application. If your sprockets are locked out or replaced with fixed sprockets, our control would not be applicable.

We are familiar with what turbo is suitable for the STI however fitment details with various RV cowling and differences in engine mounts between tailwheel and A models makes for a lot of design and fabrication work. Additionally the intercooler placement and ducting would have to be revised along with a more efficient rad setup, probably requiring extensive lower cowling mods. I don't have the time to produce components and can only offer advice on some parts and suppliers should anyone care to undertake this.

As far as other V6 engines are concerned, most aluminum V6s today have suitable power outputs and low enough weights to power 6, 7 and 8 models but be aware that all will be heavier than an O-360 installation and unless they are geared for max prop rpm to occur at power peak rpm, they will probably be inferior in performance (unless turboed). Installation of any of these is possible but be prepared for a lot of work making the mount, cooling system and possible cowling mods.

NSI lessons

Hi Dan

I have about 90 hrs on my NSI EJ25 package and seem to have sorted it out OK but the following may be of interest.

The engine dynos 162 hp at the prop flange at 6000 RPM so with maybe 10 or more horsepower being consumed in the gearbox, I am never going to match a Lyc for fuel burn.

The performance is less than an O 320 with a max of 155 KIAS at a DA of 2000' although it will exceed 180 KIAS (more than VNE in the 9A) very easily in a shallow descent such as a high speed demo pass down the runway (it sounds fantastic with its modified cams and tuned internal exhaust) but of course this is not smart.

Cooling has been an issue, especially during downwind taxiing but has been pretty much overcome with the addition of electric radiator fans and header wrap for the muffler and upstream exhaust pipe. In flight cooling is good and there is probably room to reduce cooling drag with further work on the cowl outlet and possibly an adjustable cowl flap. I suspect that turbo installations will require a lot more work to reconcile cooling/cooling drag.

The aircraft is heavy at 1,155 lbs but it has tip tanks, a BMA Efis with 2 axis a/p, redundant engine computers, sensors and coils, a backup battery and an extended storage compartment running about 6' back from the baggage area.

In a funny way I have enjoyed dealing with the problems over the last few years which were probably responsible for NSI's demise but it has been expensive. Short of copying or buying a proven package, prospective auto conversion enthusiasts should probably be aware of the liklihood of design issues leading to substantial delays and expense.

Having said that I really like what I have ended up with, especially the ease of starting, smoothness, virtually no engine management, power, very quiet cruise and the fexibility of being able to use the prop as an air brake if required.

Regards.

Rupert Clarke
RV-9A Melbourne Australia

Thanks for checking in here Mr. Clarke. That's some of the first solid feedback on NSI that I've encountered in years of watching this area of alternative engines. I've always thought the NSI setups appeared to be rather elegantly designed. They were doomed, as I understand it, mostly by questionable business dealings, combined with the reality that even an elegantly designed package like this probably needed years of testing and tuning before it could be honestly promoted as a reliable package.

Could I ask a few follow up questions based on your post?

As I understand it your first NSI engine needed to be replaced, correct? Was it overheating that doomed the first one?

Might you briefly summarize for us the "bugs" (besides cooling issues) you've solved on the installation?

At what RPM's is the engine turning at 155 KIAS? Am I correct that the true airspeed would be somewhat higher? Are you comfortable cruising at this speed...or do you basically feel like you are beating the snot out of the engine to get 155 KIAS?

What is the redrive (PSRU) ratio on your package?

Do you have the NSI CAP propeller? Do you like it? Do you trust it?

Where is the radiator located on your installation...horizontally behind the engine?

Finally...off topic here...are you satisfied with the BMA EFIS? Did you have alot of trouble before getting it right?

Thanks

Dan
Chicago
RV-9A Tail kit

NSI Experience

Hi Dan

Please call me Rupert.

The first engine failed with two seized big end bearings being the piston rod/crankshaft bearings for cylinders 1 and 3 (luckily on short final) after about 5 hours of flight time but substantially more engine time.

The reason for the failure was probably due to overheating while ground running, although dirt contamination during assembly or the consequences of the severe backfires experienced while trying to start the engine with the supplied engine computers (which would not handle the variable frequency ignition trigger signal coming from the 58 tooth sender during cranking with a light flywheel) could have been factors. The extensive ground running, mostly without cowls fitted and therefor radiator effectiveness was due to efforts to identify and remedy the starting problem.

The second rebuild (NSI replaced the first engine) was precautionary because of concerns that in the dying days of the company assembly may have been compromised by use of substandard parts or poor workmanship. It was also an opportunity which became available when I decided to dyno tune the engine to properly fuel map the Motec M4 ECUs which replaced the original units.

By far and away the biggest "bug" was the innapropriate ECUs. I never adopted the NSI wiring setup so complications which arose with that were avoided. Other items which needed attention were the used valve springs which failed to meet Subaru specifications and were certainly too weak for an engine expected to run at 6,000+ RPM on takeoff. I also had a problem with frayed wires in one fuel injector connector. Normally the loss of one cylinder on an EJ25 would be hardly noticeable but my system is now running a closed loop O2 sensor so the remaining 3 cylinders were over-enriched by the 8% maximum trim when the sensor recorded the unburnt oxygen from the failed cylinder. It definitely caught my attention on climb out.

NSI used a lot of second-hand parts to instal its SOHC 2.2 heads on new 2.5 blocks. The fuel injector connectors including terminals and a short length of wiring were spliced onto the new loom. The engine/prop packages offered by NSI's successors Maxwell Propulsion Systems (complete unit should be on display at NW EAA Arlington next month ?) use a new unmodified SOHC 2.5 engine so this stuff is really ancient history.

Another problem with my NSI package was the prop pitch gauge or lack of it and to a lesser extent the safety pins within the prop hub which were intended to prevent a runaway prop (someone leaving their finger on the pitch switch on the stick grip) taking you into negative pitch while in flight. The pitch gauge is really important to set the takeoff/go around pitch although in flight the tacho is the indicator of choice.

I never received a gauge but many who did experienced failures. I have been running with a small laser bouncing a beam off a mirror on a blade collar with the reflected signal being collected by a row of optical fibres and displayed in the cockpit.

The safety pin within the prop hub can be sheared off by the much stonger motor which was supplied with later packages and will then cause binding within the hub. I have not yet really addressed this problem but will probably remove the pin and rely on a much more "in your face" pitch indicator.

I mentioned the remedial heating mods in my last post but omitted a change which I made to reduce the "free" airflow over the engine. As you are aware the NSI installation has a large and deep horizontal radiator behind the engine which is fed by ducts on the inside of the cowl carrying air to a plenum chamber above the radiator. Negative pressure from the cowl outlet would normally assist with airflow over the radiator but this was (in my opinion) being lost to the excessive amount of air flowing straight through the balance of the cowl inlets, over the engine and out through the same outlet as the radiator air. I have reduced and diffused this free air with ss mesh screens but probably have a long way to go to obtain optimum cooling and minimum drag.

At 155 KIAS the engine is running at max continuous power, WOT and 5,800 RPM. The gearbox ratio is 2.12:1 so the prop is spinning at 2,736 RPM. At this power setting the engine feels busy and a bit coarse (it is much smoother at WOT and 6,000+ RPM which is what I use for takeoff) but the airframe is also beyond its sweet spot and starting to experience a fair bit of buffet. TAS was a bit higher but less than 160. Of course there is no guarantee that my plane is perfectly rigged or that I was flying dead level so these numbers should be taken with a grain of salt.

I do have the NSI CAP propellor which is a 72" two bladed (Whirlwind manufactured composite blades) +32? to -22? electrically adjustable unit. Apart from the comments above I am really happy with mine and would not swap it for anything.

My BMA G3 Efis One has been a bit of a learning curve and although I think that I will soon receive a terrain database for Australia which will enable a VFR map display I am probably not the person to give you a balanced opinion of its functionality. Hopefully when I become more familiar with it and perhaps also some software/database tweaks it will become the feature that I was looking forward to.

Sorry about the long reply - maybe a single picture would have been better.

Rupert

Fascinating. Thank you very much for posting this information! Best real info I have ever read on on a flying NSI package.

clarkefarm said:

Hi Dan

Please call me Rupert.

Sorry about the long reply...

Rupert

Click to expand...

Rupert...

Thanks for this excellent information. Nothing "too long" about it. This is rare and solid information. Thanks.

The second rebuild (NSI replaced the first engine) was precautionary because of concerns that in the dying days of the company assembly may have been compromised by use of substandard parts or poor workmanship.

Other items which needed attention were the used valve springs which failed to meet Subaru specifications and were certainly too weak for an engine expected to run at 6,000+ RPM on takeoff.

NSI used a lot of second-hand parts to instal its SOHC 2.2 heads on new 2.5 blocks. The engine/prop packages offered by NSI's successors Maxwell Propulsion Systems (complete unit should be on display at NW EAA Arlington next month ?) use a new unmodified SOHC 2.5 engine so this stuff is really ancient history.

Click to expand...

I've always felt that Eggenfellner's philosophy of not opening the engines is a really good one. Obviously there are compromises involved, but leaving the basic engine unopened/unmodified instills a certain level of confidence. Your experience bears out the reality that opening the engine in order to optimize cams or valve springs or whatever comes with a certain level of risk.

It occurs to me that if the successor company...MPS...is well funded, honest, and meticulous in preserving the best NSI features in a new package...that something pretty good could come out of the whole mess. Right now there is very little substance on their website other than a promise not to take customer's money until they can deliver engines. They'll have a big reputation deficit to climb out of, however.

Dan
Chicago
RV-9A Tail kit

My view on hot cams in aircraft conversions has always been- don't- unless the mods are really well researched by someone who really knows what they are doing. The high lift, high duration cams I see advertised by many just plain scare me with stock rockers and unknown valve springs. I seriously doubt most claims of increased power at the same or lower revs than stock. Never saw much of that on my dyno.

I've seen so many cases of coil bind, retainer to guide interference, valve to piston clearance problems, improper surface treatment of reground cams, base circle reductions and resulting improper rocker arm geometry that reliability is a real question.

When I see the profiles selected by some with high ramp rates and crazy overlap. I shake my head. This stuff has bitten many. Taking engines apart is fine if you know what you are doing, a disaster if you don't. The more OE parts in an engine, usually the more reliable it is.

rv6ejguy said:

I know Dan Hawken quite well (just visited him a couple weeks ago) and we supply the ECUs for the Mini Merlin V6. Dan is a very smart fellow with decades of practical mechanical experience. The drive was designed and built by him. It is a belt unit, robust and well flight proven.

Dan has offloaded the Mini Merlin design and drawings to Titan last year who I think now has subcontracted machining and assembly to someone else.

For the RV9, the latest atmo EJ25 rated at 173hp could do a good job at close to Lycoming weights if the redrive ratio was selected to allow the engine to spin up to 6000 for takeoff (about 2.2 to 1). I'd expect cruise fuel economy with this setup to be at least 10-15% less than an O-320 but auto fuel could offset this in $ perhaps. 4400 would give you about the same cruise power as an O-320 at 75%.

Click to expand...

Ross...

Just half joking here, but what is Dan Hawken doing now that he's offloaded the Mini Merlin project? Is there any way you could talk him into developing a FWF engine package for RV's? If not Dan...someone else?

I think it would be a labor of love, but the potential is there for a good package to sell in the hundreds. Taking nothing away from Jan (who has survived and even prospered in a historically brutal marketplace)...but I think Egg has cornered the market at this point more by achieving basic competency and by default than by the overwhelming excellence of the package. It would be clearly a tough, tough endeavor, but...basics of a new package might be...

1. Goal of net performance equivalent to a 180 Lyc. Notice I used "net performance" and not "horsepower" equivalency. I suppose a new 180 hp package would need to generate 190 hp at the prop flange (maybe 200 hp from the engine) to overcome the inherent cooling drag issues with a liquid cooling engine and the power cost of a redrive.

2. Goal of a "bolt on" package for RV's that requires no airframe mod's for installation.

3. Choose one of Subaru's latest 4cyl 2.5L engines....with no internal mod's...unopened.

4. Mildly turbocharged...to allow for more power at lower rpms and decent performance at altitude. But turbo'd gently enough to avoid the need for an intercooler. Maybe this is impossible?

5. The turbo could alleviate the need for a muffler, correct?

6. Design an engine mount in a style more like NSI's than Egg's.

7. Careful cooling design. Incorporate massive cooling capacity. Carefully consider how air flows through the engine compartment. This is the hardest and most important part, I think. Perhaps use a rear mounted radiator something like Belted Air Power's. As I have surveyed this (and having no personal experience, of course) it appears theirs is the best designed liquid cooling system out there. They have a large single radiator for simplicity. According to their website, as well as the various magazine articles on BAP that I have encountered, they have had zero engine cooling issues (some oil cooling issues, however) while producing 180 to 200 genuine hp. I have no way of confirming the claims here, of course.

8. Figure out some way to get prop blast air to flow through the radiator while operating on the ground. Avoid the complexity/weight of cooling fans.

9. SDS/Racetech EFI & ECU's...fully redundant, etc., etc.

10. Maybe design a header tank to alleviate the need for dual high flow fuel lines in and around the cockpit and back and forth to/from the wing tanks? Maybe a flush NACA scoop to cool the header tank and diffuse the vapor lock issue inherent with having a fuel tank in a hot cowling.

11. New Hawken-designed single belt redrive. 2.2:1. Or get Belted Air to develop one with this kind of ratio. From what I gather recently, the cooling issues of Egg's geared redrives are significant and annoying...and and have been possibly under-appreciated in the past. I'm guessing that a single-belt redrive could save weight too.

12. Create a distinctive but tidy cowling to enclose all of this.

13. Fly it around & tweak it for a hundred hours before actively promoting it.

Of course...there is always the good old American liability problem to contend with.

Well...I'm daydreaming too much. I'm going out for a run along Lake Mich before dark...

Dan
Chicago
RV-9A Tail kit

djvdb63 said:

Listers...


4. Crossflow seems to have burned their bridges with the RV community. http://www.crossflow.com/.

Click to expand...

Boy, you got that right. I gave up ever getting support from Crossflow. Since I was not the original purchaser of the package, they did not even want to give me the time of day.

Too bad, because the Subaru boxer engine is just about one of the strongest and most reliable designs there is. You have to really, really work to break one.

I have friends who race the EJ20 (2.0 liter) in sand cars, running 30+ lbs of boost and putting out 450+ horsepower, and they run the same engine for a whole season.

Just about the only thing keeping me from using one on an RV is the lack of a good, reliable, reasonable cost, redrive.

The other thing I like is the cheap availability of the engines. Low mileage used ones can be had for as little as $400 plus shipping.

djvdb63 said:

Ross...

Just half joking here, but what is Dan Hawken doing now that he's offloaded the Mini Merlin project? Is there any way you could talk him into developing a FWF engine package for RV's? If not Dan...someone else?

I think it would be a labor of love, but the potential is there for a good package to sell in the hundreds. Taking nothing away from Jan (who has survived and even prospered in a historically brutal marketplace)...but I think Egg has cornered the market at this point more by achieving basic competency and by default than by the overwhelming excellence of the package. It would be clearly a tough, tough endeavor, but...basics of a new package might be...

1. Goal of net performance equivalent to a 180 Lyc. Notice I used "net performance" and not "horsepower" equivalency. I suppose a new 180 hp package would need to generate 190 hp at the prop flange (maybe 200 hp from the engine) to overcome the inherent cooling drag issues with a liquid cooling engine and the power cost of a redrive.

2. Goal of a "bolt on" package for RV's that requires no airframe mod's for installation.

3. Choose one of Subaru's latest 4cyl 2.5L engines....with no internal mod's...unopened.

4. Mildly turbocharged...to allow for more power at lower rpms and decent performance at altitude. But turbo'd gently enough to avoid the need for an intercooler. Maybe this is impossible?

5. The turbo could alleviate the need for a muffler, correct?

6. Design an engine mount in a style more like NSI's than Egg's.

7. Careful cooling design. Incorporate massive cooling capacity. Carefully consider how air flows through the engine compartment. This is the hardest and most important part, I think. Perhaps use a rear mounted radiator something like Belted Air Power's. As I have surveyed this (and having no personal experience, of course) it appears theirs is the best designed liquid cooling system out there. They have a large single radiator for simplicity. According to their website, as well as the various magazine articles on BAP that I have encountered, they have had zero engine cooling issues (some oil cooling issues, however) while producing 180 to 200 genuine hp. I have no way of confirming the claims here, of course.

8. Figure out some way to get prop blast air to flow through the radiator while operating on the ground. Avoid the complexity/weight of cooling fans.

9. SDS/Racetech EFI & ECU's...fully redundant, etc., etc.

10. Maybe design a header tank to alleviate the need for dual high flow fuel lines in and around the cockpit and back and forth to/from the wing tanks? Maybe a flush NACA scoop to cool the header tank and diffuse the vapor lock issue inherent with having a fuel tank in a hot cowling.

11. New Hawken-designed single belt redrive. 2.2:1. Or get Belted Air to develop one with this kind of ratio. From what I gather recently, the cooling issues of Egg's geared redrives are significant and annoying...and and have been possibly under-appreciated in the past. I'm guessing that a single-belt redrive could save weight too.

12. Create a distinctive but tidy cowling to enclose all of this.

13. Fly it around & tweak it for a hundred hours before actively promoting it.

Of course...there is always the good old American liability problem to contend with.

Well...I'm daydreaming too much. I'm going out for a run along Lake Mich before dark...

Dan
Chicago
RV-9A Tail kit

Click to expand...

Dan got out of it to pursue other activities. He was tired of customers wanting to change all sorts of things, then calling him up and telling him stuff didn't fit/ work etc. I couldn't believe the dumb things people we doing. No chance he'd be going back to it.

To get O-320 performance, the new 173hp EJ25 would work naturally aspirated. To have O-360 performance, a low boost EJ25 would do it at 35-38 inches and somewhat lower rpm. Leave the engines alone for sure. Lower profile intake manifolds would have to be used in most cases to use the factory cowling.

Intercooler is a must unfortunately. Muffler is not required with the turbo.

NSI's mount was pretty busy. With some good thought, a lighter and simpler mount could probably be made. The SOHC EJs have less suitable pickup points than some others.

A Cheyenne type inlet below the spinner could feed a single low mounted rad under the sump with cowl flap. A sealed duct with proper shape is a must. The Belted Air rad setup works but is high drag in my opinion and the plenum setup makes it hard to seal with the flat four shape. Low drag means no turns in the cooling airstream according to my tests and historical study. Use a Visteon type custom rad core with oval tubes. The inlet placed in this part of the prop arc should provide decent ground cooling. The aim would be to keep coolant temps under 110C at 90 knots and full power at ambient temps around 35C.

EFI is not a problem but we shun the redundant ECU idea. More failure modes actually due to isolation relays and extra wiring.

Unfortunately to avoid the possibility of vapor lock, the complicated full return fuel system is required IMO.

There are already several good drives on the market. A couple form NZ and I do like the Marcotte as well. Not a real fan of belt drives but if designed correctly, there are some really good ones out there too.

The Egg drives do seem to need a lot of cooling which may be due to the gearset layout. My Marcotte runs cool with no additional airflow ducted to it.

You've hit the nail on the head about what is out there and why so far.

Ok, get started...