Viking

[dlomheim]

Originally Posted by GhostRider32

... Would I buy a old Subaru conversion from Jan? Absolutely not as there are too many complaints about them. Will I buy a Viking from Jan when I am ready? Quite possibly...

I think the majority of the folks on the "Alternative Engine" list are all for more alt. engines getting into RVs, and being successful! I think we also want perspective buyers to be aware of past issues with products, materials, techniques, etc.; so they can go into any deals or installs with their "eyes wide open". A buddy of mine is still owed $10K+ for parts never provided from 5+ yrs ago, and in spite of numerous requests for a refund, he has only received hollow promises of payment.

Hoping it all works our for you!

Doug Lomheim
RV-3A sold
RV-9A / Mazda 13B (FWF)

[DanH]

Originally Posted by dlomheim

I think the majority of the folks on the "Alternative Engine" list are all for more alt. engines getting into RVs, and being successful! I think we also want perspective buyers to be aware of past issues with products, materials, techniques, etc.; so they can go into any deals or installs with their "eyes wide open".

Exactly right.

A lot more than just the folks on the alternative engines lists too. The world is changing. Lines between "traditional" and "alternative" are blurring, and vendors are learning.

What do you call a kerosene fueled compression motor with roots at Mercedes-Benz, converted by Continental Motors?

http://continentaldiesel.com/typo3/index.php?id=2&L=1

Closer to this thread, consider the Raven and AeroMomentum examples.

At one time, the alt-engine world was truly dumb as dirt about torsional issues. Yet 20 years ago, smack in the middle of the swamp, Raven's Jeron Smith developed a frictional true damper in parallel with a soft element, all packaged in the upper sprocket of a belt drive. The system is light, and simple, and has been sold on various Suzukis for going on two decades. It works, and it's now offered on the Fit motor.

AM's Mark Kettering is an engineer, did a traditional math analysis of the torsional issues, and elected to go with a rubber ring soft element. A rubber ring coupler has no significant true damping, but is for sure a standard approach to powertrain frequency tuning, the real issue with a PSRU. Mark reportedly then ran his beta models on airboats for a few years, a very good way of conducting "real world testing" transferable to aircraft. And AM builds its Suzuki-based engines from new parts.

Even Jan is learning; the Fit layout incorporated a rubber ring coupler right from the start. The last iteration of the Subaru incorporating the springs and one half flywheel from the stock Subie dual mass system was clever, but an engineered rubber coupler is hard to beat from a design standpoint. The designer can pick from a long list of offerings in the exact torsional stiffness needed for the application, and have the ability to swap if the first torsional estimates were wrong. Don't laugh; it happened to Rotax with the early 582 C-box.

Torsional issues are only one aspect of developing a successful bolt-on powerplant. Nobody is perfect, and nobody gets it perfectly right the first time. Any of the above could have a software glitch, for example, or decide to make an improved component available for retrofit. When that happens, it really does come down to how it gets handled, a matter of business practice. There are very good engineers who are terrible at customer satisfaction issues, CSI experts with zero engineering skills, and great imagineers who make terrible business decisions.

Here's the thing; blanket arguments of superiority (or lack thereof) are just wrong. Too often the strongly held opinions are based on little more than a belief system. It works both ways. A lot of long-term players will never trust Jan. The water is muddy enough that they may never trust any alternative vendor. At the same time, right here we're reading strongly worded statements from supporters with no actual flight time beyond an up-and-down demo ride. I wouldn't go so far as to say they are "passed off as fools or stupid" as written by one poster, but for some there may be an element of "don't yet know what they don't know".

Nobody is done learning until we die. Let's stick closely to hardware and technical discussion. Debating belief without seriously addressing technical is just a pointless flog.

[deene]

Amen, Dan...well said.

[Reese]

Originally Posted by DanH

Raven's Jeron Smith developed a frictional true damper in parallel with a soft element, all packaged in the upper sprocket of a belt drive. The system is light, and simple, and has been sold on various Suzukis for going on two decades. It works, and it's now offered on the Fit motor.

Kinda ....... Jerod has a few prototypes flying, but has said recently the project is delayed to focus on family

[rv6ejguy]

Very well said Dan.

[BillL]

Way to go Dan. Hit the nail on the head, as usual.

We get life's reminders from many experiences. It was a pleasant Alabama afternoon and I went to a picnic in college with a bunch of friends and their dogs. A couple, (canines) were particularly at one another, but not drawing blood, but persistently running through the ranks and became annoying. Before any owners quelled the 30 min ordeal, suddenly one dog who had been quietly laying and watching jumped up as the two ran by, aggressively and very quickly separated the two, and in literally two seconds, all was calm for the remainder of the day.

[WingsOnWheels]

A little off topic, but all this talk has me thinking about another Honda engine that seems like a good fit for aircraft conversion. I own a 2006 Honda Aquatrax PWC. The engine is a 1235cc I4 with fuel injection and electronic ignition. Being a PWC engine, the controls are quite simple and it is designed to be a drop-in unit with few external connections. The version I have is turbocharged and rated at 165hp (not sure of the RPM for that rating). The normally aspirated version is rated at 125hp. The engine is very compact and connects to the jet drive via a damping coupler. According to the Honda site, this was a purpose built marine engine. The displacement is similar to the Fit, but bore and stroke are quite different. Probably based off one of their motorcycle engines.

The engine has been very reliable in a very harsh environment, but that doesn't mean it would be good in an aircraft application. I have no idea how much it weighs, and cooling would be interesting to figure out. Just thinking out loud really, but makes sense to me.

[Reese]

Originally Posted by WingsOnWheels

A little off topic, but all this talk has me thinking about another Honda engine that seems like a good fit for aircraft conversion. I own a 2006 Honda Aquatrax PWC. The engine is a 1235cc I4 with fuel injection and electronic ignition. Being a PWC engine, the controls are quite simple and it is designed to be a drop-in unit with few external connections. The version I have is turbocharged and rated at 165hp (not sure of the RPM for that rating). The normally aspirated version is rated at 125hp. The engine is very compact and connects to the jet drive via a damping coupler. According to the Honda site, this was a purpose built marine engine. The displacement is similar to the Fit, but bore and stroke are quite different. Probably based off one of their motorcycle engines.

The engine has been very reliable in a very harsh environment, but that doesn't mean it would be good in an aircraft application. I have no idea how much it weighs, and cooling would be interesting to figure out. Just thinking out loud really, but makes sense to me.

Some people have used motorcycle/snow mobile style engines.

Usually you have to run those engines up to 8,000 rpm to get the power out of them though.

More common to see engines like that used by ultralights.

[WingsOnWheels]

Originally Posted by Reese

Some people have used motorcycle/snow mobile style engines.

Usually you have to run those engines up to 8,000 rpm to get the power out of them though.

More common to see engines like that used by ultralights.

Would defiantly need to see the torque curve to make any real assessment. Max RPM for that motor is 7000rpm according to a website I found). Since it is a shorter stoke than the Fit engine, peak torque is probably at a higher RPM. However, it is the same size motor as the Viking/fit engine so the applications should be similar. The packaging of a marine engine seems more appropriate for aircraft conversion than an auto engine, so the conversion may be easier.