Engine Selection

[Quinton Oliviero]

It's a bit premature yet, but I've really been turning over engine selection options in my mind recently. Jon Matcho posted a link to Kitplanes magazine's 2017 Engine Buyer's Guide which really got me going, and right now I'm seriously considering 3 options for my Cozy IV:

 

Option 1: Lycoming IO-360

Pros: It's a proven bulletproof design. The default option.

- Better yet, the guy who sold me his project has got one available

- I already have the appropriate engine mount.

- Decades of unchanged design means that parts and support are ubiquitous

Cons: Included in the (not insubstantial) price is the engine. That's it. No starter, alternator, mags, wiring harnesses, oil cooler, baffling, exhaust. Realistic all-in price is north of 25k USD.

- Because of its nature(direct drive, large torque pulses), inexpensive propellers marketed to the homebuilt market are unsuitable (IVO, warp drive, etc.)

 

Option 2: Jabiru 5100

For those of you who recognize the engine, there's only one guy as far as I can tell who ever flew with it on a Cozy (Larry Hill) and this is his engine.

Pros: Cost. Larry is selling the engine and associated accessories(in his words "starter, generator, mags, carbs, and mufflers") for < 6k USD. The mount would be extra.

- Light. All-in weight < 260 lbs

- Still direct drive, but 8 smaller cylinders makes it "smooth and quiet" relative to the Lycoming. 

- Parts aren't as ubiquitous as the Lycoming, but are available relatively cheaply.

Cons:

- Cooling. Some of the cylinders are hard to keep cool, and Larry eventually gave up on the design after a 45 minute taxi at Oshkosh caused one of the cylinders to overheat, stuck a piston ring, and blew a bunch of oil out the breather tube. (FWIW it will be a cold day in hell before I go to Oshkosh)

- Despite smaller torque pulses the IVO prop still proved itself to be unsuitable for Larry. I wouldn't take my chances on a warp drive either.

- Rarity. Larry had the only Cozy flying a Jabiru and not many mechanics will be familiar with the design.

 

Option 3: Automotive Conversion (Mazda 13B-MSP with Powersport PSRU)

According to Kitplanes' guide, Atkins Rotary will still build a complete kit with Renesis engine, Powersport PSRU, ECU, EFI, EI, alternator, and starter for 16k USD. I'm focusing on this design in particular because the available Subaru and Honda conversions are more expensive than Lycomings and use unproven PSRU designs. There are some proven one-offs (Ross Farnham's Subaru RV-6) but I'm not an engineer and I don't have their expertise.

Pros: Cheaper than the Lycoming. Cheaper even than a brand new Jabiru factory-direct, though not as cheap as the one mentioned above.

- Very smooth engine (though not very quiet, really)

- Engine loves a turbo. Even modest boost pressure results in significant HP gains.

- Engine design simplicity and permissive failure mode. Engine can't be seized, loss of apex seals results in reduced power, but not complete failure.

- Price includes modern features other engines lack (EI, EFI, ECU)

- Use of a PSRU puts many more inexpensive propeller options on the table. (IVO, warp, Meglinsky)

Cons:  System complexity. Need for a PSRU creates additional potential for failure.

- Liquid cooling system issues cause problems for auto conversions.

- All-in weight is actually slightly heavier than a comparable Lycoming installation.

- Rarity. Rotary engines aren't even common among Mazdas. Your local Mazda dealer might know a rotary mechanic, let alone actually have one. If they do he probably has a neck beard, a computer that runs on Linux, and a Laserdisc player (because betamax was too mainstream). Even Mazda doesn't make rotary engines anymore. Aviation related rotary enthusiasts with actual experience seem to have all moved on, or are so rare that they're rumoured to exist somewhere, but nobody seems to know any. Even google searches pretty much only lead to defunct websites and my 5 year old post in the Vans forums.

 

What do you guys think? Am I missing something obvious? What issues did you have with your own engine selection and eventual installation?

[Kent Ashton]

I partial to the Lycoming.  I don’t want to have any doubt about the reliability of my engine and an airplane engine will usually warn you before it lets you down  

As you say, The history of canards is that rotary installations are often removed for a Lycoming after a while and/or they are more difficult to sell.  

Edited November 4, 2018 by Kent Ashton

[Voidhawk9]

This is certainly a topic worthy of plenty of time and research. I have been for years, and I'm still years away from installing an engine. But I have a  fair idea of what I'm going to do.

I might argue with the idea that Lycomings are 'bulletproof'. Yeah, they are generally reliable, but they have their flaws and issues (I've been aboard a twin that suffered an unidentified failure). It is just that they are so old that the flaws and fixes are very well known.

For the Jabiru, clearly, you'd need to design a very different cooling setup to make it work. Possible, perhaps with an effective eductor.

I studied and liked the rotary for a long time. I've read and re-read John Slade's site, and the experiences of others. It can be a good engine... but. It appears to be a 'dead-end' design at this point. You would need to design and integrate a turbo setup, adding to the complexity. You'd need a better cooling design. I'm just not convinced the rotary is worth it at this point.

I do like some auto conversions. Looking beyond the canard world, there are a great number of successful implemetations to study. Keeping it simple (so far as possible) and not being tempted to 'make it better' yourself (ie swapping cams, pistons etc), seem to be prime indicators for success. The Alternative Engines volumes are educational reading on the topic.

One engine that could be a great fit for a Cozy (or even maybe a Long) and one I am watching with interest is the Aeromomentum AM20T. 260hp in a lightweight package built new for aircraft use. As yet unproven, but the company and its other engines appear to have a great reputation and expertise in the field so far. The same cannot be said for some other similar engine conversion companies.

Edited November 5, 2018 by Voidhawk9

[Quinton Oliviero]

I gather Aeromomentum uses Suzuki engines? They look pretty good! That being said their unbelievably cheap gearbox gives me pause. A Powersport PSRU is like $9k, which fits pretty well with what guys like Marcotte and Crook were charging back when they still made theirs. I found a company that is making their own gearbox for aviation (specifically to transmit 250HP for Mazda rotaries) that is charging $5500. The fact that the Aeromomentum gearbox is only $1600 is a serious red flag for me. Plus to get the 260HP out of a 2L engine it looks like they needed a turbo and 10.5:1 cylinders. I wonder if a turbo could be put on the AM15 147HP version to get it to ~180? These guys are definitely worth watching. Hopefully not another Viking.

The Lycoming O-320 and O-360 are bulletproof by just about any definition(minus the infamous O-320-H2AD). Flight schools all over Canada and the US have racked up millions of hours on these things over the years, and it's the odd one that doesn't make it to TBO. I've seen some pretty gnarly failures - a friend of mine had to land on Virginia Beach after part of his O-320 decided to depart the aircraft by way of blasting itself right through the crankcase - but those stories are exceptional in part because they are so rare. It's just a shame that being the big name in the market means they still command such high prices for carbureted, magneto driven, early 20th century technology when others are offering FADEC for much less.

I've kept my ear to the ground on the alternatives, I even really considered Diesel for a while there, but the offerings are still too slim and those that are out there are far too expensive. Deltahawk, if they ever become a thing, is apparently asking $65k. Not 100% sure WAM is still producing? And Continental still doesn't seem that friendly to single purchases, more looking to power a new fleet of certified aircraft. I'd considered a Subaru EE20, but they got infamous for crankshaft failures that Subaru disavowed. The availability and relatively low cost of Jet-A keeps the dream alive though. I'd really love to see someone succeed in this area, I just feel like it's going to have to be someone much richer's passion project.

[macleodm3]

I followed the plans and went with the least expensive option.... a flying mid time Lycoming O-360.  I sold some attached components when I bought it (P-Mags, Carb, small oil cooler, automotive alternator, Skytech starter).  I had to buy a few components while installing (B&C starter & alt, FI servo, Cozy exhaust, LSE Ign, bigger oil cooler).  I'm in about $14k now(engine and accessories), with an estimated 1500 hours before recommended overhaul.  Mid-time lycoming is a bolt on solution, and the plans make is SO EZ... having everything fit (cowls, baffles, components).... all that really is a big deal.

Most Cozy's never get finished (flying), and many that do get finished don't often accumulate many hours.  If I ever get up to 1500 hours, I'll be in a VERY small minority so I truly believe a mid-time 360 is a good choice.  Yeah, I know its boring... but its in a Cozy MKIV (NOT Boring).  (but ya gotta pay attention to cam rust and exhaust valves)

IF I had to have an alternative engine.... I would consider the UL520.  Its a modern airplane engine, and several in our community are flying or installing them.

 

[CBarber]

I flew my Velocity for about 15 hours with the Mazda.  It was smooth and fast.  I used the inflight adjustable IVO prop.  I even had cooling licked.  However, I was having to tinker a lot.  The first time I took it out of the pattern to a nearby airport, I lost the engine when about to enter the pattern....came down fast, with the wind, threw down the speed brake and even remembered to use the rudders as "brakes".  No injury and no damage....even started back up and taxied to the tie down.  While that turned out to be a clogged fuel line and not specifically rotary related, it did give me pause.  So, at around that time I had some money fall out of the sky, so before I did something stupid with it like invest or pay off bills, I bought an aircraft engine (that's another story where since I mentioned I had turboed the rotary, the guy convinced me to go with the Continental TSIO-360..... then the cost increased by about $10K...to almost the point of a new Superior .... or flavor of the day....took over a year for delivery and THEN the A&P went to federal prison for selling an unairworthy prop as airworthy......but that's another story)

 

I still like the rotary, a lot.  However, I put a LOT of time in figuring things out.  With my knowledge today, I think I could get it to work as a good alternative engine.  But, that's after years and years of trial and error.  One of my key factors in finally abandoning the rotary, other than realizing my original goal was to have what I hope to be a safe and reliable airplane and not just prove the rotary as a viable option, was the retirement of Tracy Crook, the maker of the PSRU and electronics.  Tracy was the first to tell you his stuff was not plug and play...and boy, did that turn out to be true.  My ignorance combined with that created a large learning curve.  Dont get me wrong, even with some serious frustration, I really enjoyed the process.  Still do.  I crave going out and working at the hangar. 

It would have been easier, and I would have likely been flying the last several years if I had not convinced myself that spending a bit over a period of time on the rotary made sense.  I should have likely just saved during that same period of time and bought a Lyc instead.  Hopefully soon, I will fire up the Conti for the first time and hopefully, and with solid learning and experience, I will have that fast, cool, safe and reliable Velocity I crave.

All the best,

 

Chris Barber

Houston

Edited November 10, 2018 by CBarber

[Jon Matcho]

On 11/10/2018 at 8:30 AM, CBarber said:

So, at around that time I had some money fall out of the sky, so before I did something stupid with it like invest or pay off bills, I bought an aircraft engine...

Ha -- that was good for a morning laugh!  Thanks for sharing Chris!

[Quinton Oliviero]

In consideration of the wise words of people like Chris (and a few others) I've decided to limit my search for powerplants to complete FWF (or in our case FWR?) kits. I like tinkering, but I like flying more. Having a unique engine setup means having unique problems. Much as the price of a roll-your-own automotive conversion is attractive I just don't have the mechanical knowhow at this point to treat that as a realistic option. That and there's no way my wife will get in if I do!

A few more engines on my watchlist:

Aeromomentum has added a couple of engines to their selection. A naturally aspirated version of the AM20T which at 170HP might be right for a Cozy. There's also an AM24 now, which depending on weight could be very nice as well. No details on these new models as of yet, but the AM20T is advertised as 260HP for 285 lbs with a price tag of 19k, so that should give some indication. Any fears I had about the engineering of these machines have been put to bed after digging through forum posts and youtube videos of Mark Kettering. He's done his homework, and he doesn't seem the type to overpromise and underdeliver. Tons of testing, and seemingly nothing but happy customers.

The balkanization of experimental aviation never ceases to astound me, as I just discovered that the gyroplane guys have been flying Yamaha snowmobile engines since about 2013 and fixed wing guys are just getting in on the action! Mohawk Aero Craft has made a kit from the 998cc Genesis Turbo engine from the Yamaha Sidewinder snowmobile. I gather the power clocked in at over 200HP sub-200lb weight (I remember reading 204HP and 170 lbs, but I can't find the source now). Only one flying right now, though about 20 more with other Yamaha engines. Greg Taylor Mills seems very knowledgeable and enthusiastic, and I think has a genuine desire to advance the state of experimental aviation. My concern with this one is that there hasn't been a lot of testing, and none of the guys flying these things seem to have more than a couple hundred hours. Ten years ago the auto conversion True Believers like all the Subie guys (and I'm not talking about the Egg ones here, that's another story) thought they were launching a revolution until a few hundred hours later crankshafts started to fail... Scared a lot of people off. No failures on this one as of yet, and it is definitely one to keep an eye on. A > 1.0 P/W ratio is a big deal!

I'm still keeping the Diesel dream alive. P2M, an italian company, is advertising a line of diesel engines and is trying to get certified. Actually saw one bolted to a LongEZ on another forum (there's that balkanization again). All of their specs on their website are in metric, but the translation is this: The JPE01 engine is 150HP and weighs 220 lb, burns about 3.7 GPH at full power, and closer to 2 in cruise. The JPE03 is 220HP and weighs 345 lbs, burns 5 GPH at full power and 3.7 in cruise. I would avoid the 02 and 04 models as they are Hybrids. They bolt on 88 lbs of electric motor and battery to give ~30 minutes of 80 extra HP. Juice that in my opinion is not worth the squeeze. That's a lot of added weight and complexity for extra power at takeoff. Anyway, these seem like "glossy brochure" numbers and I'm sure the price tag will be astronomical, but they're supposed to be at Oshkosh this year, so we'll know more in July. They have a distributor in western Canada but it sounds like they'll have an American one this year.

[Voidhawk9]

That diesel is a 'dream' for sure. If I'm doing my numbers right, those sfc numbers are twice as good as the best high-efficiency diesels in use today - and I'm talking power generators and huge ship engines, which are much better again than their smaller counterparts!

[Quinton Oliviero]

Yeah, the numbers I'm getting are between 72 and 77 g/hp/h or about 0.16 lb/hp/h Way too low. I expect real world consumption should be like triple that!

[Voidhawk9]

Another case of 'if it sounds too good to be true, then it probably is'.

Anything more than a modest improvement over existing engines is probably marketing in an attempt to attract investors, nothing more. Still waiting on the Deltahawks to arrive as well! 🙄

In contrast, Aeromomentum is actually building and selling engines and gaining a very good reputation, I will continue watching their new engine developments with interest.

Edited March 25, 2019 by Voidhawk9

[Thompsolonian]

Aside from my PPL knowledge of the lycoming engine for my plane (for the check ride) I don't have direct experience with working on aviation engines other than the Allison t-56-A-15 (wouldn't THAT be a fun engine on a Cozy), but I can say a bit about the 13-b or similar designed rotary engines.

They have a much higer RPM, but lower torque, you most certainly would want to go with a RGB in order to bring those rip-ems down and increase your torque. Keep in mind that the fuel cosumption would be a bit higer as well, because all three faces of the rotor are working at once. I own an RX-8 and it's crazy the power I have, but with an average of around 18-20 MPG I'd be better off with a Corvette as far as effeciency goes, even my avalanche is more fuel effecient than that.

As far as maintenance, CHECK THE OIL! Much like a preflight on any plane, check it, and if it is remotely low, add oil. A rule in the RX world is if that oil light comes on once, your'e in for an engine change.

The rotary engine itself likes turbochargers, which could provide an effeciency and performance boost on your aircraft, and it would indeed run very smoothly. If you ever wanted to do your own rebuild, you can practically take the engine out and re-rig it with a modified 5 gallon bucket to hold everythign together, the engine itself is only 3 moving parts, but there are easily twice as many seals as both the sides of the rotors and the apex seals do need addressing every once in a while.

If you are looking into one taht has been turbo charged, I can ask my friend in Wisconsin who operates a shop that ONLY deals with rotary engines if he'd be comfortable providing guidance, or building up one of his spare 13-b's for you.

Edited March 25, 2019 by Thompsolonian

[Quinton Oliviero]

I appreciate the offer, but after consulting quite a few other people's experiences I have to pass on an auto conversion that's not already a FWF kit. Even experienced guys are saying it's taken them 400 hours to get things right, and given my schedule that's 2 years of work. 

I love the rotary engine, as I myself used to have an RX-8 and it was a great car, but there just aren't enough rotaries flying anymore for me to be able to get the help I would certainly need. 

Man, the idea of that power to weight ratio though... From what I gather nobody was ever really able to keep their 13B builds much below 280 lbs, but putting a turbo on it could be an easy 350HP+! And the 20B? I've seen street cars that were able to make it over 900! Obviously I don't think you'd want to run those kind of boost pressures to have any kind of life on that engine, but it's still really impressive. 

[Voidhawk9]

Maybe Titan or Supermarine would sell you one of their LS V8 FWF setups. Heavier than the other options, but similar to a -540, which has been done several times. And WAAAAY better fuel economy than a rotary. Plus, they are common, still in production, reliable, multiple PSRU options, and relatively affordable. They appear to be in use on various types with great success, with little or no modification to the engine. 350-450hp at conservative RPMs.

Edited March 26, 2019 by Voidhawk9

[Quinton Oliviero]

The Supermarine V8 LS2 looks beautiful, but at 48k AUD it's a little out of my price range. (http://www.campbellaeroclassics.com/sitebuildercontent/sitebuilderfiles/spittybrochure.pdf)

The Titan LS3 kit though, wow. 300 HP and it's only $6250 USD? They say their gearbox and conversion kit aren't included, so conservatively add another $10k for that? They've also got suzuki engine kits to directly rival Aeromomentum. Assuming my $10k estimate is right they slightly undermatch price, horsepower, and weight but their gearbox ratio is far more attractive than AM's 2.588:1 (who wants peak horsepower at 2240 prop RPM?). I also really like the look of that Honda. (http://www.titanaircraft.com/engines.php)

[Voidhawk9]

I get the impression from the Titan guys (I hang around the Titan Air Corps forum to feed on engine discussion) that few are installing Suzukis anymore. Ditto on the Hondas - I looked into that one a bit myself. The LS3 is not much heavier, and puts out way more power at more conservative RPMs, whereas the Honda is working really hard to hit its numbers.

You might enjoy this video:

 

[Quinton Oliviero]

I do! Though that looks like a homegrown solution. Looks like a tight fit in there, and is that a Ballistic gearbox? That thing looks and sounds like a monster, and he claims 495 HP! Electric Supercharger do you think?

Oh I'm with you on the LS3. Cheaper, and better P/W. Definitely would have to put in a little more nose ballast though, eh?

The titan guys are just up the road from where my project is right now in Ohio. Might be worth going to have a look!

[Voidhawk9]

Plenty of room to the sides, but vertically a bit tight, yes. Custom cowl will be required - but if you are installing something other than an O-360 already, that should not be a big problem for you! It does appear to be a Ballistics redrive, which I like, well proven and numerous, but quite a low offset from the crank, so the engine has to be up fairly high.

You are right about ballast. Putting batteries in the nose will help. I'm going to install hydraulic retracts, so the hydraulic pump can go up front, that should do the trick nicely.

[Anthony P]

Who is installing or interested in the D-Motor offerings?

[jackalak]

What do you guys think about putting an AM15T in a cozy classic/cozy III?  

https://aeromomentum.com/am15t-160hp/

I'm looking at buying a used cozy, right now it has an O-320-ED2 in it but it's been hangered for 15 years.  I'm figuring I could buy that plane, take off the engine and sell it as is for 10k for someone to overhaul, and then buy the AM15T for 18k.

That 150hp O-320 supposedly weighs 268 lbs.  The AM15T supposedly only weighs 215lbs, has 10hp more, horsepower, and turbo.  I'm only 165 lbs, so the aircraft balance would be better for me with a lighter engine for solo flying. Also, I live in the Denver area and want to routinely fly over the rocky mountains, so a turbo would be handy. 

[zolotiyeruki]

I'm not a builder nor a pilot (yet!), so I can only echo advice I've heard from others:  if you want to just fly, get a Lycoming.  If you like to tinker, and are ok with the build taking considerably longer, and if you can engineer the installation well, then an auto conversion might be ok.

I've spoken to Mark Kettering (owner of Aeromomentum), and I've been pretty impressed with his approach and engineering chops.  His is a much more rigorous approach to engine and PSRU design than what I've seen from Viking.