What do You Want in An Engine

[garnt.piper]

WE all have our opinions, but something I find interesting is that most all the previous entries here were still opting for avgas or unleaded autofuel spark ignited engines. Why? These types of fuel cost more to refine, and are less thermodynamically efficient than a diesel/avtur compression ignition engine. The heavier fuels are also less volatile, thus safer, and denser so you get more calories per volume of tank, meaning less space required for tanks or more energy available in your current tank. Avtur/diesel is available in huge volumes for the industrial and jet aviation markets, so economies of scale are there. The refining of the heavier fuels, as I understand it, is also less energy intensive, so less fuel is burnt to make the product in the first place. The high octane fuels were developed for the demands of the military and huge volumes were made in refineries built to service the military and civil aviation markets (without regard for cost), but they have moved on, we must to, and the sooner the better.

A diesel engine doesn't need spark plugs at $20 each, or magnetos/electronic iginitions to fail. They like to run slow, so no reduction gearbox like most auto conversions need.

I'd like a two stroke ~200hp turbo diesel air cooled direct drive with mechanical fuel injection running at 2500rpm all day. Make it a horizontally opposed 4 or 6 cylinders, using a proprietary supercharger (Whipple?) so it will fit in a similar space to the current engines. Add standard spec accessory drive pads to accept vac pumps/alternators/governors as desired.

I know the diesels have been coming for years without much of an arrival, but I do think they are the future of GA. And so does Lyc and Cont I think, thus the burst of activity in the Lyclone market in the last few years. Why didn't people build Experimental clones before recently? Threat of lawsuits for stolen intellectual property or patent infringements from the monopoly holders. Now the writing is on the wall for avgas and the big manufacturers are happy to cash in whatever they can with the established technology. It is standard marketing in practice - sell the product for a premium on High Street one day, and then sell volume at Walmart the next when the technology or newness has had its day.

Don't get me wrong, I like my Lycoming for its "Elegant Simplicity' (??), but a diesel could be more elegant and simple.

[johngoodman]

Originally Posted by johngoodman

Unless you invent a new technology there's nothing new under the sun in fossil fuel engines.



You are probably right, but this engine by Axial Vector sure looks interesting: http://www.axialvectorengine.com/

I went ahead and contacted the Axial Vector folks and got a quick response. Not what I wanted to hear but honest:

"Dear John:

Our plan calls to license to major companies only

Thank you for your interest in our company"

[hevansrv7a]

This was not even the only time.

http://www.vansairforce.com/communit...t=axial+vector

[John Courte]

Sounds to me like what most people want is a simple, cheap, reliable
~200hp engine. This is clearly possible, because from a complexity standpoint, there isn't anything terribly complex about the O-360.

I think the major hurdle would be design and prototyping costs. 3D CAD design and simulation will take you a long way in this arena, but when it's time to manufacture, you need to go where it's cheapest. This may rub some people the wrong way, but you could do your production in China or India for a lot less than you could here in the USA.

Here's a question, without meaning to hijack the thread: If you could buy a Lyclone made in China/India/Indonesia for $5k that had a 2000hr TBO, would you?

One of the reasons you can't right now is because those countries aren't known for their encouragement of civilian experimental aviation, but if one was available I certainly would, if it met the requirements below:

1. Weight and form-factor similar to the (I)O-360. If liquid-cooled,
less the coolant, rads and plumbing required to ditch the heat of
200hp, and capable of fitting in the same space. Nobody wants
to cut up their cowling or engine mount if they don't have to,
and not everyone can even if they wanted to.

2. 2000hr TBO. As an early adopter, I'd settle for 1200hrs with a
vendor-supported teardown and inspection with discounted
upgrades or repairs.

3. Cheap. There is no reason an engine has to cost 30,000 dollars.
There just isn't that much metal in it and manufacturing capacity
is becoming a global commodity. With all the bells and whistles,
it should cost less than 10k. GM's LS6 can be had for less than 6k,
and it's certainly not their highest volume engine product. Of
course, this is just for the long-block. but you don't need much more
than that in an aircraft application.

4. Uses a Lycoming-style dynafocal mount, for easy installation with
existing kit parts. See #1.

5. Solid-state distributorless electronic ignition. There are enough
aftermarket ECU's on the shelf to choose from without having to expend
a ton of money developing one, and if I don't like the one you bundle
with the engine, I can delete it and buy the one I want.

6. Aerobatic capability as part of the standard design. Don't split your
design/prototyping efforts for two different markets. Make it up in
volume.

7. Vendor support. Hopefully you never need it, but there needs to be
someone around to pick up the phone when you have technical questions
or you need to send something back.

8. User-servicable, Soviet style. You want people to be able to tear this
engine down and put it back together with Wal Mart and Pep-Boys tools
without fear of upsetting some finicky nano-tolerance, and you want
the service manual to be concise, accurate, complete, and very well-
illustrated.

9. No PSRU. This engine should be able to employ a fixed-pitch wood
prop just as easily and safely as a typical certificated constant-speed
prop.

10. Option for Constant-speed prop. By option, I mean It's ready for it,
but you don't have to use it. Add it later without needing a new
crankshaft and case. Use off-the-shelf C/S governors and other
hardware.

Maybe this is a bit much to ask, but if I could carve this from a solid block of unobtanium, I would.

[rv8ch]

Originally Posted by John Courte

... This may rub some people the wrong way, but you could do your production in China or India for a lot less than you could here in the USA.

Here's a question, without meaning to hijack the thread: If you could buy a Lyclone made in China/India/Indonesia for $5k that had a 2000hr TBO, would you?

I guess if you have to ask this question, you have not been looking at the "made in china" tags on all the other things you have bought lately!

People will buy the cheapest thing that they perceive will do the job for them, no matter who makes it, or where it is made.

[John Courte]

you're right, Mickey. I guess what I was feeling out was whether or not the experimental community has any qualms about flying behind developing-world-manufactured equipment, which is often regarded as cheap and poorly made. Tools, of course.. Everything in my shop was manufactured in the US 30 years ago or China 2 years ago.

If there's some quantifiable way to measure manufacturing and materials quality before it gets released into the wild, I'd have no problem with it. But multiple thousands of hours of documented run-time are the only thing that matter to some folks, and that's fine.. It helps us all get taken a little more seriously when we say we're building airplanes in our garages.

With auto conversions, especially the Subarus, the manufacturing process is stable and a lot of the R&D is already done, it's just not purpose-built for our app, like the Lycs, so we work around that. Until something better AND cheaper comes along, I'll be flying behind the H6.

Seriously, though, what would be a ballpark figure for prototyping a 4- or 6- cylinder engine of any stripe, not just aircraft?

[kevinh]

Originally Posted by John Courte

Seriously, though, what would be a ballpark figure for prototyping a 4- or 6- cylinder engine of any stripe, not just aircraft?

Actually, if someone was going to be doing the 'China engine thing.' I think the best way to go would be to clone a Lycoming. A good idea - I just don't know how the volumes work out.

[jcoloccia]

Originally Posted by John Courte

Here's a question, without meaning to hijack the thread: If you could buy a Lyclone made in China/India/Indonesia for $5k that had a 2000hr TBO, would you?

Yes, absolutely. If there are two more or less equal products, and the USA made product is competetively priced (it's allowed to be more...just not orders of magnitude more) I'll buy American.

In general, though, if some other country had a blow out product that had the same performance and was significantly less expensive, I'd certainly buy that product instead. It's capitalism at work. Eventually, our own industry would play catchup and resolve the imbalance, just like our auto industry did. I'm a "Buy American" man through and through, but I'm not into coporate welfare. If it was China specifically, I'd have to think about it for reasons which I won't get into here.

I fear it won't ever happen with GA, though. There's just such a ridiculously low volume that it's just not worth it. Also, aircraft engines are one trick ponies. They're totally unusable in anything else unless you happen to have a 100+ MPH breeze handy. This is sorta' the alternative engine problem in reverse (trying to use auto conversions in aircraft....possible, but the environment is completely different than anything these engines were ever designed to see).

Maybe someone will come up with a modular engine that can do things like swap back and forth between air cooled/liquid cooled, etc, but the components themselves are designed to mount interchangebly. I don't even know how that could be made to work and it's probably a ridiculous concept anyhow. Point is, there might be some hope of being able to design one engine that could be used in aircraft and boats, for example. That would be significantly more volume and may make it worth it for someone to pursue.

[xl1200r]

What if you built a new case and just used pistons, cylinders and heads from an existing, high-volume engine like many of the air-cooled motorcycle engine still out there? You'd only really to develop the stuff between the cylinders then, and you'd still have the simplicity of an air-cooled engine.