The No Alternative section

[Canadian_JOY]

Lots of good points here. I own a Lyc and a Continental, and prefer the Continental over the Lycoming, for a number of reasons. There's internecine warfare even in the certified engine world! :-)

With my biases clearly stated above, I believe the builders who choose to install an alternative engine are indeed experimenters; for that, I take my hat off to them.

I truly feel sorry for the numbers of builders who bought an alternative engine package from a vendor who essentially sold the package as though it were a well-engineered, proven design, when in fact it was little more than a lab rat waiting to die a premature death. Some of these vendors have done the alternative engine movement a tremendous disservice, not to mention the reckless and irresponsible imperilment of their paying customers. Many of those vendors have gone the way of the Dodo. Good riddance. Some of them are still around, having shifted to other projects. To their potential customers, caveat emptor would be the understatement of the day.

At our field we have a Mazda rotary-powered aircraft which has experienced its trials and tribulations. The builder is indeed a man of towering patience.

Similarly, our EAA chapter president is very close to first flight in his canard pusher airplane, powered by an alternative engine. When I see the efforts he has gone through to make his core engine and its supporting systems safe and reliable I feel honored to be even loosely associated with the breed of people who work so hard to put the "E" in EAA.

[N427EF]

with virtually zero failures in automotive engines during that time.

Flying exactly on what kind of airplane?

I have stacks of books and loads of information on people trying to make use of alternative engine and there was a time no one could talk me out of trying
one of those.
None of the promoters ever to the best of my knowledge has ever succeeded in the long run without significant risk and cost in achieving "fright" time much beyond a few hundred hours.

The Franklin is probably the best of the "alternative engine" choices but still
needs considerable engineering to make it work in an RV.

I am always interested to hear of success but promoting false hope based on
wishful thinking is not advancing your cause.

[f14av8r]

Personally, and as a new entrant to the EAB world, I find it disheartening that nobody produces a new technology aviation engine that can compete on price / performance with these ancient Lycoming / Continental engines. These basic designs have been around a long time, and given good service but they've been around too long in my opinion. Proven technology is one thing but, in this day and age, I have to think we can design and build a better aviation engine. Yeah, I know, it's all about liability and certification. I wonder though, is this really the BEST engine that we have the technology to build, or simply the engine that we have the will to push through the bureaucratic process?

Hmmm, maybe I need to start a new engine company!

[Jordan1976]

Arguably, Rotax has succeeded at creating a new aircraft engine with price and performance in line with other engines. They just focused on the 100HP range, not the 150-200 HP range we like. They even have full digital FADEC engines.

What they have proven in a sense is that you can't really increase power, decease fuel burn, decrease weight, or decease price a lot.

[N941WR]

Originally Posted by Canadian_JOY

...
I truly feel sorry for the numbers of builders who bought an alternative engine package from a vendor who essentially sold the package as though it were a well-engineered, proven design, when in fact it was little more than a lab rat waiting to die a premature death. Some of these vendors have done the alternative engine movement a tremendous disservice, not to mention the reckless and irresponsible imperilment of their paying customers. Many of those vendors have gone the way of the Dodo. Good riddance. Some of them are still around, having shifted to other projects. To their potential customers, caveat emptor would be the understatement of the day....

That is exactly why I struggle with alternative engines. There have been engine builders out there promising the world and delivering a small rock. Then the builder ends up buying a second engine, for which he probably doesn't have the money, after spending his engine fund on a failed experiment.

What I don't get is why do new engine designers always try to sell their unproven engines at the same price as Lycoming? If I were trying to get a new engine into the market, I would sell them at half the competitor's price until I had a proven product. Once a number of customers are successfully flying, then start jacking the price up. Until you have a proven product, don't bother me with your dreams and unproven designs.

The Franklin engine is a proven design. The four cylinder engines are not well regarded and the only reason I can think someone would put one on an airplane today is to keep an antique as "original" as possible. Their six cylinder engines, for which I have a number of hours behind are good engines but not well regarded because they are no longer in production (in the USofA).

[rv6ejguy]

UL power is coming along with a good recipe I believe but tend to have a similar somewhat arrogant attitude with regards to customer service support that Rotax does in some cases I've heard from some of their customers. That doesn't help either of these companies in my view. The price point though is the trouble with these- around $200/hp.

There is a new line of 2, 4 and 6 cylinder, opposed, air cooled, DD aero engines under development in the US at the moment designed to compete with the likes of Rotax, UL and Jabiru at a reduced price point. These will be non-certified to keep development costs down. The experimental world needs a US produced alternative to the imports I believe.That's about all I can say at this point and wish them luck.

As far as the auto conversions go, the most successful to date was the RAF 2000 Gyros powered by Subaru EJ engines. A group survey back in 2006 found about 125,000 flight hours collectively on the 600+ airframe fleet with few problems. The key was a good PSRU design, turning the same lightweight prop and reliable, cooling, fuel and electrical systems- duplicated over and over -the key to repeatable success IMO.

We have a fair number of one offs over 750 flight hours now, a few over 1000 and a few more over 1500 showing it can be done with proper design but no other large fleet of vendor engines has shown tens of thousands of successful flight hours to date that I'm aware of if that's what it takes to demonstrate reliability to the masses.

Talk's cheap, if you want to show the world, you actually have to show the world with several flying examples with many hundreds of trouble free hours each as a minimum. That won't come cheap or fast.

[g zero]

Value vs price . Let's assume a Lycoming cost $30,000 new ,after 2400 hrs (TBO ) it's still worth at least $8500 , that comes to about $9 per hour of use .
Say you can get a Franklin for $20,000, after the 1500 hrs (TBO ) what's it worth ? It's like the 2 stroke ultralight engines , not cheap per hour of use .

[Toobuilder]

I find it funny that a Franklin (or PZL), a real aircraft engine line with millions of flight hours, is considered an "alternative" on this forum.

[rv7charlie]

Originally Posted by Jordan1976

I don't think you are doing your point any favors by trying to disparage the traditional engines as poorly designed. The idea that a naturally aspirated 360 cubic inch engine (5.8L) could produce 600 HP at 2,700 RPM reliably and afford-ably is pretty aggressive. That's just over 100 HP per liter, something naturally aspirated street cars only achieved first in about the year 2000 (and at 8,000+ RPM).

At 2,700 RPM, that would be a BMEP of 490 PSI, well over 2X the BMEP that a Nascar or F1 engine runs at, and deep into the territory of never been done.

The goal of an aircraft engine is not HP per liter. It's a combination of size, weight, fuel efficiency, reliability, and of course the ability to turn a propeller at subsonic speeds.

You'll do better advancing the "alternative" engine world by finding a proving a design that can actually put out the power and reliability you state a Lyc engine doesn't have rather than just stating it doesn't.

I never said any of that stuff (except the 1/3 part :-) ).

For the record, I do believe that Lycs are very good a/c engines. I'm just willing to look for something 'better'. Rutan (and others) did that, and we got the 1st privately funded trip to space.

You're setting limits that I'm not setting. Reno F1 regularly runs at far north of 4000 rpm and close to double the real world HP of a stock O-200. There's a former Reno biplane racer with an O-320 that operates north of 3600 rpm at airshows.

Point is, the core engine will produce *far* more power than Lyc rates it for. Their 'rated power' number is massively derated for precisely the reasons you specify.

Modern 6 liter automotive engines easily produce far north of 400 HP *continuously*, and in proving it, they do it with multiple engines, each in 500 hour continuous test sessions cycling between max torque and max HP, with repeated cycling of operating temperature coolant with near-freezing coolant pumped through the engine. (IIRC, the FAA mandate for a/c engine certification is less than 1/2 that time on a test stand, in far more benign conditions.) How long would one of those engines last, and how reliable would it be, if operated at roughly 1/2 it's rated HP for takeoff and 35-40% continuous (assuming proper execution of cooling, drive issues, etc)? Weight on the current crop (with redrive and cooling system) is very close to comparable HP a/c engines.

But the point of this thread remains: why can't the Lyc guys either be constructive or at least show us the same courtesy we show them? We know all their arguments, and most of us, at least, know which are valid and which are basically religion. The 1st guy to criticize in this thread has a sig line that says he's flying a 250 HP RV-8. Do any of the Lyc guys see the inconsistency(-ies) in his position? I certainly do.

Charlie

[rvbuilder2002]

Originally Posted by rv7charlie

Rutan (and others) did that, and we got the 1st privately funded trip to space.

Very true!
He also spent decades before that thinking outside of the box with new aircraft designs that he built and flew, but with only a couple of exceptions, each one had a traditional aircraft engine (or engines) powering it.