Viking Aircraft Engines, thoughts? (Honda piston AE?)

asicer said:
Um, disagree. Vehemently.;)
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The "whistle" sound wasn't coming from the engine. (which for the sake of this thread, was a V-12 and water cooled) It came from the inner most and recessed gun ports.
 
Timbeck2 said:
The "whistle" sound wasn't coming from the engine. (which for the sake of this thread, was a V-12 and water cooled) It came from the inner most and recessed gun ports.
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The whistle is frosting on the cake. :)
 
We are seriously considering a Viking 130 for our Zenith CH750 Cruzer. They have been selling it for quite a few years now, so far without any significant problems that I am aware of. The previous 110 had a few, relatively minor, issues like that it did not make as much power as expected, had cold start issues and a single failed rubber torsional dampening element.
All of these problems were addressed.

While it is heavier than a Rotax, it is still quite a bit lighter than any Lycoming. As it is geared, it also allows for the installation of large diameter propellers. Jan Eggenfellner, the owner of the company, won last year the Zenith STOL competition with his Zenith CH750 Cruzer! I believe this says a lot about the power of the engine.
The only other options in this power range are the Jabiru 3300 with 120 hp and the UL350iS with 130 hp. Both are however direct drive and reach max. hp only at 3300 rpm. The upcoming Rotax 915iS might be another option, but it will be around $31,500!

It also appears that whenever Viking comes up in a forum, somebody has to mention that his former Subaru conversion company went belly up and that he left unhappy customers behind. And, of course, there has to be a reference to the Yahoo forum, in which nothing but the "truth" is being discussed: The Yahoo forum is pretty much dead, and the main purpose of the little bit of activity was apparently to badmouth whatever he does. :rolleyes:

I reached out to a few Viking customers and they were all happy with their engines and spoke highly about the factory support. Viking has also grown to a a total of 11 people. IMHO, not bad.

I actually like that it is base on a Honda engine, the amount of R&D and the quality standards required for automotive engines, goes far beyond what even a company like Rotax can do. It is also not continuous operation at 55 - 75% power what kills a car engine, it is granny starting the car to drive the few yard to the mailbox. The gearbox Viking attaches to it also appears rock solid: They disassembled one after around 500 hours of intensive demo and cross country flights, it still looked like new.
 
There's an awful lot of converted VW engines flying around in home builts, including most Sonex designs and Airdrome Aeroplanes WWI replicas. Good for smaller designs around 85 HP. Cheap and pretty reliable.

Cheers
 
coloradobluesky said:
And dont forget, water cooled engines have to have water jackets. So their engine blocks are heavier.
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I'm sure you can find an example showing that, but the firewall forward package for a 100 hp Rotax weighs less than the competitive products from Continental and Lycoming.
 
German guy said:
It also appears that whenever Viking comes up in a forum, somebody has to mention that his former Subaru conversion company went belly up and that he left unhappy customers behind. And, of course, there has to be a reference to the Yahoo forum, in which nothing but the "truth" is being discussed: The Yahoo forum is pretty much dead, and the main purpose of the little bit of activity was apparently to badmouth whatever he does. :rolleyes:
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I suspect he learned a lot during the Subaru years. Also, I suspect he engineered/developed/found/stumbled <pick one> into a good combination with the Honda engine and the PSRU he's using.
 
Ted DuPuis said:
You're severely discounting the importance of the air in the equation here. You can easily see 50-100F differences in CHTs between good baffles and bad baffles on the exact same airframe. BTDT many times.

Mixture setting and oil cooling matter as well, but air is by far the most important factor in the equation.
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Not so much discounting air as a cooling agent, just that oil (and fuel) seem to be as important. But, I'm not an engineer; maybe one could chime in, regarding the cooling factors in GA recips?
 
coloradobluesky said:
And dont forget, water cooled engines have to have water jackets. So their engine blocks are heavier.
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kyleb said:
I'm sure you can find an example showing that, but the firewall forward package for a 100 hp Rotax weighs less than the competitive products from Continental and Lycoming.
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As I recall, Rotax has water cooled heads and air cooled cylinders so the first statement still holds true.
 
asicer said:
As I recall, Rotax has water cooled heads and air cooled cylinders so the first statement still holds true.
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The water cooled version of Rotax engines also don't fly in the flight levels.
 
Sundancer said:
Not so much discounting air as a cooling agent, just that oil (and fuel) seem to be as important. But, I'm not an engineer; maybe one could chime in, regarding the cooling factors in GA recips?
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Well, I'm an engineer who knows a thing or two about these engines.

As I said, air is the primary means of cooling. Any engine produces the majority of its heat in the areas surrounding the combustion chambers and thus needs some means of dissipating that heat. You'll see some form of cooling means surrounding it. In a typical liquid cooled setup, you'll have water jackets inside a cylinder head that water runs through, which lets water run through to absorb the heat. You also have a lot of heat going through the exhaust ports, as you'd expect. Less heat is in the cylinder walls, but certainly still enough heat to think about.

In an air cooled engine this cooling is more visible. If you look on the cylinders, you'll see that the cylinder head area (which is where most of the heat is) has lots of fins on it, certainly more than the cylinder barrel area.

The oil exists for lubrication, although it does perform some cooling functions. However its flow rates are not enough to provide all the necessary cooling. Normally oil cooling is for areas where one cannot get enough air/water to cool the area, or just incidental cooling that occurs for lubrication. The oil piston squirters I mentioned are a good example. Those squirt oil on the underside of the pistons, because there's no good way to get cooling airflow to that location. To provide a visual example, if you look at the size of the oil cooler compared to the size of the fins, the oil cooler is much, much smaller. Some of the very small aircraft engines don't even have an oil cooler - the natural convection of the air flowing over the engine/sump is enough to keep oil temps in check. That gives you an idea of the relative importance of oil vs. air.

The "fuel cooling" aspect is important on piston aircraft engines, but really it's most important for the high powers used in takeoff and climb. If you are needing to use significant excess fuel to keep the CHTs cool then you either are running too hard, it's really hot, or your baffles are in bad shape. For some of the higher power turbocharged planes it's a bit different, but even those will usually cool just fine if you have your baffles set up correctly. The 25-75F ROP range is the worst operating point, and where many run. Your CHTs will be the highest there. Peak-LOP or 100+F ROP is better from this perspective.

Ultimately, most A&Ps do a poor job of keeping baffles in good shape. There is a big misconception that old airplanes were "overcooled" (nothing could be further from the truth in most cases, although there are some) and a lot of A&Ps also just don't understand what it takes to optimize baffles, or they know but choose not to because the couple tubes of red RTV gets messy, especially when you take things apart.

You tend to see the fuel cooling the most since the air is effectively fixed (unless you have cowl flaps) and fuel can have a significant impact, but fuel is not the intended primary source of cooling for these engines during flight. Your fuel consumption will skyrocket if you use fuel as a primary source of cooling.
 
Why would Rotax choose the higher RPM/reduction model if the 'best' purpose built design(the classic lycoming/continentals) syncs engine rpm to prop limitations?
 
exncsurfer said:
Why would Rotax choose the higher RPM/reduction model if the 'best' purpose built design(the classic lycoming/continentals) syncs engine rpm to prop limitations?
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There's more than one way to skin a cat. Rotax already knows how to make smaller engines, so that's what they were comfortable with. My recollection is they had their teething pains, although certainly the newer engines seem to do well.
 
exncsurfer said:
Why would Rotax choose the higher RPM/reduction model if the 'best' purpose built design(the classic lycoming/continentals) syncs engine rpm to prop limitations?
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If direct drive is "best" why did Lycoming, Continental and Pratt&Whitney (and others) choose to build engines with gear reductions?

There is no obviously "best" way to do it. Every design has it's advantages and disadvantages, and a lot depends on what the current chief engineer prefers.
 
Rotax was founded in 1920 and managed to survive WWII. In 1970 the company was bought by Canadian Bombardier Inc. where their engines ended in everything from snow mobiles to motorcycles and eventually into small aircraft.
https://en.wikipedia.org/wiki/Bombardier_Inc.
Continental started making aircraft engines in 1929. Lycoming started making engines in 1929.
 
Thanks @citizen5000, so I wasn't the only one who assumed that Rotax was a newcomer
 
Capt. Geoffrey Thorpe said:
If direct drive is "best" why did Lycoming, Continental and Pratt&Whitney (and others) choose to build engines with gear reductions?
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Because every manufacturer makes mistakes?

Because spinning them faster made more horsepower. The downside for all of them was increased weight and complexity while decreasing reliability. The market chose the simpler, more reliable direct drive as 'best'.
 
azblackbird said:
Tons of V-8 powered aircraft around that make the rounds at the various airshows and fly-ins. Like this one... you have to admit, this sounds almost as good as the real one. ;)

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Tons? Really... :rofl:

Go to EAA Oshkosh this year. Count up the number of V-8 auto engine powered experimental airplanes on the field. Calculate what fraction that represents of the total experimental registrations. Then see if you still think there are "tons".
 
SoonerAviator said:
I'm sure the challenge of cutting weight in a diesel is quite the difficult task. They run at much higher internal pressures, which necessitates stronger (usually heavier) components than the gasser counterparts.

Second, is the fact that there's almost no payback in trying to get a new diesel powerplant certified as a replacement for existing airframes. The demand just isn't there for anyone who has 100LL available.

So, that leaves you with trying to build/design a compression ignition engine for use in an aircraft that hasn't been certified yet. Pretty small market reduced to an even smaller market.

Final answer: despite the obvious challenges in shedding enough weight, the lack of demand for new piston singles pretty much explains why so few are even interested in making an attempt.
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It would seem perhaps a wee bit more involved than that. Maybe the following series of pictures will shed some light on the challenges. This afternoon I took these photos of an Austro AE300 turbodiesel installed on a DA42 NG owned by an aerial surveillance company located in the same complex as my office. This is an excellent platform for what they do. Not all that good for what I do in my twin, however.

The macro conclusion I came to after looking this thing over is that it is, once again, proof positive that every problem can be overcome with enough development funding and engineering. Especially so with Teutonic engineers. But that doesn't necessarily make the overall final overly complex result all that desirable. The engineers among us will know the exactly what I mean. :)

This engine is ~170 hp, roughly equivalent to a Lycoming IO-360, which was (is?) an optional power plant on the DA42 airframe.

Exhibit 1: The exhaust manifold and expander side of the turbocharger housing are cast iron. Lotta heat coming out of those cylinders as evidenced by the discoloration on those components, and the rather substantial looking thermal sensor mounted in the cowl space directly above the center bearing of the turbocharger.
IMG_0262.JPG

The good sized radiator under the engine to help dissipate some of the heat:
IMG_0266.JPG



Exhibit 2: Whole lotta shakin' going on. Note in the first picture above the elaborate anti-vibration device on the exhaust. That assembly is welded stainless with an SS corrugated liner under the SS mesh wrap just ahead of the exit exhaust pipe. The next picture shows one of the steel cable engine tethers. There is one at each of the four engine mounting points. This is not an aerobatic, airshow performer. :)
IMG_0265.JPG

Exhibit 3: The beefy gearbox. To get the required output the engine has to turn at an RPM too high for even a reduced diameter 3-blade prop. The props are composite MT, apparently to try to help offset the extra weight of the engines. The mechanic that maintains this airplane told me the reduction drive has a slip-clutch assembly to buffer the prop from the very strong power pulses the diesel produces. I've heard before this is one of the major issues to overcome with piston diesel aircraft engines.
IMG_0264.JPG

Exhibit 4: I rather like this serpentine belt; seems an elegant, low power loss solution. In addition to the crankshaft drive pulley this assembly has 5 more, 3 idlers (manual tensioner) and two accessory for the coolant pump and the alternator. Looks pretty robust but a belt or idler bearing failure will result in loss of coolant flow and no amount of "richening the mixture" is likely to help the resulting situation.
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GRG55 said:
Exhibit 4: I rather like this serpentine belt; seems an elegant, low power loss solution. In addition to the crankshaft drive pulley this assembly has 5 more, 3 idlers (manual tensioner) and two accessory for the coolant pump and the alternator. Looks pretty robust but a belt or idler bearing failure will result in loss of coolant flow and no amount of "richening the mixture" is likely to help the resulting situation.
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The Austro AE300 is a modified Mercedes-Benz OM640 engine that they use in some of their European market cars (Mercedes USA diesels are V6's).

Here's a better picture of the serpentine belt that you like so much, albeit as used in a Mercedes automobile rather than a Diamond airplane:

45-moteur-om640.jpg
 
The heat that comes out of those auto derivative diesels is no more than the heat you find on a turbo piston aircraft engine. They opted to keep the factory cast iron exhaust manifold (which doubles as a turbo support) rather than fabricate something lighter weight that also changes the configuration. However, you certainly could get weight out of the engine there. Look at the exhaust system on the turbo Twin Cessnas (which has a pretty restrictive AD, mind you). It's very lightweight.

Really, they decided that they didn't want to change those Mercedes-used components and instead focused on the PSRU instead. The MT props do help to offset some of the weight gain, but the other thing they do is absorb the vibration pulses better than typical metal props. Note these are torsional vibrations rather than visible vibrations. The slip clutch does help in the PSRU, although there are other ways around that issue.

Vibrations, yeah, worse on a diesel, but standard aircraft engines can shake a bunch, too. Back when Lycoming had the service center at the hangar, there was a policy to never let a customer see their 4-cylinder plane run with the cowling removed. The 4-cylinder engines have a 1-3-2-4 firing order, meaning that both cylinders on the one side fire, followed by both cylinders on the other side. This makes for some interesting visible jumping around with the cowl off. In the end, the OEMs put in appropriate dampers to make sure that the vibrations are isolated from the cabin, regardless of engine.
 
GRG55 said:
azblackbird said:
Tons of V-8 powered aircraft around that make the rounds at the various airshows and fly-ins...
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Tons? Really... :rofl:

Go to EAA Oshkosh this year. Count up the number of V-8 auto engine powered experimental airplanes on the field. Calculate what fraction that represents of the total experimental registrations. Then see if you still think there are "tons".
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There were roughly 28,000 homebuilt aircraft on 1 Jan 2016. About 1600 of them (~5.7%) were registered as having auto engines.

In addition, there are almost 4,000 aircraft which are listed as having an "AMAT/EXP" engines. I've used NTSB accident records to attempt to extract the percentages of given engine types, and estimate about a quarter of them are auto derivatives. Hence, I estimate about 2800 (about 10% of the fleet) homebuilts are powered by auto engines.

Now...how many V-8s? Of those 2800 engines, more than eighty percent are Volkswagens, Subarus, Hondas, or Corvairs.

350 aircraft have GM (non-Corvair) or Ford engines. Some percentage of them are V-8s, but similarly, some are V-6s or even straight 4s (Model A engines in Pietenpols, for example).

My WAG (based on scanning engine types in accident records) is that, probably, around half of those 350 aircraft may have V-8 engines. How many are actually flying? Don't really know. The FAA estimates that 40% of registered homebuilts are inactive.

Whether this represents a "Ton" (in other than the avoirdupois sense) is left as an exercise for the reader.

Ron Wanttaja
 
The question is not how many built using a car engine but how many are flying regulary with one. Likely none to few.
 
Vance Breese said:
Why?
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Well, because its air cooled for starters (depending on the Harely). I always thought bike engines would be better than car engines because a lot of bike engines are indeed air-cooled (no radiator). Moreover, they tend to be lighter since bikes tend to be lighter. The most widely used car engines, VW's and Corvairs, are also air-cooled. Gets rid of one heavy system to break.

Were I to try such a thing I might look to the parallel fours that powered the Honda CB750's, but I suspect their power output to be on the anemic side.
 
I'd love someone examine the installation of the RED V-12 diesel on Yak-152 in a similar vein to the one Mr. GRG55 posted for DA-42. So far pictures are rather incidental, like the one attached.

14141487_1141699165896480_5601066472201615666_n1.jpg
 
steingar said:
Well, because its air cooled for starters (depending on the Harely). I always thought bike engines would be better than car engines because a lot of bike engines are indeed air-cooled (no radiator). Moreover, they tend to be lighter since bikes tend to be lighter. The most widely used car engines, VW's and Corvairs, are also air-cooled. Gets rid of one heavy system to break.

Were I to try such a thing I might look to the parallel fours that powered the Honda CB750's, but I suspect their power output to be on the anemic side.
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How about the horizontally opposed (boxer) BMW bike engines I remember from the 1960s & 1970s? I don't recall ever seeing anyone try to use one of those in an experimental, even though the form factor is similar to conventional certified aircraft piston engines.

That would be interesting, especially given BMW's origins as an aircraft engine maker.
 
X3 Skier said:
So you think the 2800 aircraft mentioned earlier are all grounded?

Cheers
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They aren't a Cirrus. Why would anyone wish to leave the ground in anything else? :rolleyes:
 
wanttaja said:
There were roughly 28,000 homebuilt aircraft on 1 Jan 2016. About 1600 of them (~5.7%) were registered as having auto engines.

In addition, there are almost 4,000 aircraft which are listed as having an "AMAT/EXP" engines. I've used NTSB accident records to attempt to extract the percentages of given engine types, and estimate about a quarter of them are auto derivatives. Hence, I estimate about 2800 (about 10% of the fleet) homebuilts are powered by auto engines.

Now...how many V-8s? Of those 2800 engines, more than eighty percent are Volkswagens, Subarus, Hondas, or Corvairs.

350 aircraft have GM (non-Corvair) or Ford engines. Some percentage of them are V-8s, but similarly, some are V-6s or even straight 4s (Model A engines in Pietenpols, for example).

My WAG (based on scanning engine types in accident records) is that, probably, around half of those 350 aircraft may have V-8 engines. How many are actually flying? Don't really know. The FAA estimates that 40% of registered homebuilts are inactive.

Whether this represents a "Ton" (in other than the avoirdupois sense) is left as an exercise for the reader.

Ron Wanttaja
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Takes a large experimental airframe to accommodate a V-8 derivative. Few of those available, and of those that are they are built in comparatively small numbers - generally daunting, expensive, complex projects to assemble. I have an acquaintance who lives nearby who owns an experimental bush plane with an Orenda V-8. That thing is massive, about the size of a Beaver. It's a one-off with that engine.
 
GRG55 said:
Takes a large experimental airframe to accommodate a V-8 derivative. Few of those available, and of those that are they are built in comparatively small numbers - generally daunting, expensive, complex projects to assemble. I have an acquaintance who lives nearby who owns an experimental bush plane with an Orenda V-8. That thing is massive, about the size of a Beaver. It's a one-off with that engine.
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Ben Haas (R.I.P.) put a "840 HP NASCAR grade V8 Ford 347 detuned to approx 400 HP" in a CH-801:

https://backcountrypilot.org/features/category/featured-bush-planes/the-beast-zenith-ch801

As to the OP's question, I have no knowledge.
 
GRG55 said:
How about the horizontally opposed (boxer) BMW bike engines I remember from the 1960s & 1970s? I don't recall ever seeing anyone try to use one of those in an experimental, even though the form factor is similar to conventional certified aircraft piston engines.

That would be interesting, especially given BMW's origins as an aircraft engine maker.
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There was an ultralight manufacturer in germany in the 80s that used the BMW boxer engines.

640px-WD-Sunrise_II.jpg

(this picture shows an earlier version with a Citroen KKHD engine, later he used an R1000 engine conversion)

The manufacturer didn't last, but that wasn't related to the engines.
 
GRG55 said:
The next picture shows one of the steel cable engine tethers.
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Cool write up and great pictures. I'm afraid to ask though why it needs tethers...

P.S. - why the 1,3,2,4 firing order?
 
Tantalum said:
Cool write up and great pictures. I'm afraid to ask though why it needs tethers...
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Presumably there is some concern about engine mount failure from the stresses or vibration being imposed by the Diesel engine.

The only prior times I have seen such tethers were on aerobatic aircraft and race planes where the engines are highly stressed and subject to potentially catastrophic failure.
 
Tantalum said:
P.S. - why the 1,3,2,4 firing order?
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It takes a little while of looking at the possible combinations of crankshaft and pistons for this to fully make sense, but basically for a flat 4 you have to either:

1) Have two cylinders on one side fire followed by two cylinders on the other side
2) Have all pistons move in the same direction at the same time

Option 2 would be far worse on vibrations and forces. Option 1 means that you have pistons going opposite directions to balance out forces. So, it's the lesser of the two evils.

This is also why I like 6 cylinders aircraft engines a lot better, but they undoubtedly come with extra complexity. The service history of the 4-cylinder aircraft engines shows that they are extremely durable engines, and generally far outlive their 6-cylinder counterparts.
 
GRG55 said:
Presumably there is some concern about engine mount failure from the stresses or vibration being imposed by the Diesel engine.
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That is somewhat disconcerting... I guess we'll see how the fleet ages and if engine departure ever actually does occur. I would think having a dangling engine there (possibly still running) would be worse than just losing the whole thing, but then of course your weight and balance is severely upset so lesser of two evils I suppose

Ted DuPuis said:
basically for a flat 4 you have to either:

1) Have two cylinders on one side fire followed by two cylinders on the other side
2) Have all pistons move in the same direction at the same time
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Thanks, between those two options number 2 does sound worse, but I'll have to do some more research about why you couldn't (or wouldn't want to) have say 1,4,2,3 order so I can better understand. I remember reading a while ago that firing order was also the reason that 6 cylinder engines were more "smooth" than 8 cylinder engines, despite there being less cylinders
 
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