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  #41  
Old 10-01-2018, 05:46 AM
rocketman1988 rocketman1988 is offline
 
Join Date: Jun 2010
Location: Sunman, IN
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Default Well said.

Very well said.

It is the experimenters that lead the way and make strides in progress possible, not the followers...
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  #42  
Old 10-01-2018, 10:39 AM
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rmartingt rmartingt is offline
 
Join Date: Nov 2006
Location: Savannah, GA
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Default

Quote:
Originally Posted by rongawer View Post
Quote:
Originally Posted by N941WR View Post
Remember, auto engines are not designed to run at 75 or even 55 percent power all the time. The normal duty cycle for an auto engine is up and down, never continuous at one power setting. Even on the highway, with the cruise set, an engine is very lightly loaded.

Aircraft engines, on the other hand, are designed to make TBO while spinning on the redline at 75% power. That is a HUGE difference in duty cycles.
This statement is not true.
...
Even more so, what wears an engine out is not the continuous at-power operation, but the duty cycles themselves. If operated at a continuous rpm and load, just about any engine will last longer due to the stabilized oil film and temperatures of components.
That is exactly my point. I may be being pedantic, but the idea that "airplane engines can maintain 75% power for long periods but car engines can't" is a load of manure, and it's that part specifically that I'm objecting to. Pretty much any piston engine in normal use will sustain rated power for ridiculous periods of time, so long as fuel and ignition are properly set, and you maintain sufficient lubrication and cooling. Go look at the testing done on mass-production car engines and you'll see them running wide-*** open for hundreds of hours.

You may be interested to know that Part 33 requirements for piston engines, and specifically 33.49, only specify a 250 hour endurance test--a series of cycles between full power and various cruise settings.

The rest of my statement is not intended to encourage or discourage anyone. I'm merely trying to show that there's a lot of work that goes into designing and building a proper firewall-forward installation. Using a traditional engine, and especially the engine supported by the kit manufacturer, means that builders can leverage all of the work done previously by others throughout the industry, over many decades.

What I'm trying to get at, is if you're going to try and encourage someone to go the traditional engine route, then cite the right reasons instead of repeating old wives' tales.


For full disclosure, I will be using an O-360 with an electronic fuel injection package. As interesting and professionally challenging as I would find it to work on an engine conversion, I've chosen to use a traditional engine as the "base" plus a popular alternative fuel/spark system, because I can leverage others' past experience with both and get many of the benefits I want without having to go whole hog on a conversion.



On the topic of the engine that never went into production: something a lot of people don't realize is that you don't just have to get the design itself certified. You also have to get the production line certified*, to include maintaining incredible volumes of records and paperwork, and setting up entire portions of your production and quality-control groups the way the FAA wants you do do them. Liability concerns may have played a part, but I suspect a large portion of the decision probably hinged on the FAA not allowing this company to just divert engines off their normal production line for aircraft use. The FAA would probably want an entirely separate and isolated line, with completely different QC and recordkeeping procedures than the rest of the company used. And I suspect all of the supplier components and subcomponents would be subject to similar restrictions, or at least face more severe ones relative to auto-industry norms.


*okay, well, technically you don't have to get a production certificate, but not doing so likely becomes more expensive once you get out of single-digit production numbers...
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  #43  
Old 10-01-2018, 08:36 PM
bayoubengal bayoubengal is offline
 
Join Date: Feb 2018
Location: Perry GA
Posts: 23
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As a lifelong motorcycle rider I have seen the Chinese reverse engineer half of Honda Motor Company’s engines. They sell for dimes on the dollar. Im surprised we have not seen this with Lycoming engines. Im not promoting this, just surprised. Yes they can build poor quality but they can also build excellent quality. They build engines for several BMW motorcycles at the Loncin plant.

Also as a side note to the current discussion, Lycoming considers its engines at TBO at the earliest of the published TBO hours or 12 years, whichever comes first...
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Last edited by bayoubengal : 10-01-2018 at 08:51 PM.
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  #44  
Old 10-18-2018, 03:13 PM
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rongawer rongawer is offline
 
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Location: Brentwood, CA
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Default

Quote:
Originally Posted by bayoubengal View Post
As a lifelong motorcycle rider I have seen the Chinese reverse engineer half of Honda Motor Company’s engines. They sell for dimes on the dollar. Im surprised we have not seen this with Lycoming engines. Im not promoting this, just surprised. Yes they can build poor quality but they can also build excellent quality. They build engines for several BMW motorcycles at the Loncin plant.
The reason there hasn't been a largely competitive engine to the Lycoming IO-540 in its purpose is not reliability or capability - it's simply economics. The economics of liability, research, development and marketing. Consider how many Lycoming engines are produced in a year, and then know that is about one day's production for even the lowest volume car manufacturer. Rotax recently posted a news item that they achieved their 15,000th 912 engine production and over 30,000 of the 582's over 40 years. Toyota makes about 14,000 every work day.

It's all about the numbers...mostly financial numbers - not aviation vs automotive purpose.
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  #45  
Old Yesterday, 05:43 AM
Nukeflyboy Nukeflyboy is offline
 
Join Date: Aug 2007
Location: Granbury, TX
Posts: 93
Default Quick Build or Legacy for RV10

You can see that auto engine conversions create quite a discussion thread.

Here are a couple other thoughts not mentioned so far.

You should see if any company will insure a 10 with an automotive engine and if so, what is the cost. If I ran the compnay, I would not.

If have been to a thousand airports across the US, Canada, Bahamas, Alaska, and I recall only a handfull that had mogas. The ones that did were no big savings.

You should consider resale value. I personally know 3 builders just in my town that installed auto conversion engines only to abandom them after a couple years of frustration. They then installed Lycs. I would tell anyone asking my advice (built two) to never buy an auto conversion.
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  #46  
Old Yesterday, 11:19 PM
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rongawer rongawer is offline
 
Join Date: Dec 2007
Location: Brentwood, CA
Posts: 338
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Quote:
Originally Posted by Nukeflyboy View Post
You can see that auto engine conversions create quite a discussion thread.

Here are a couple other thoughts not mentioned so far.

You should see if any company will insure a 10 with an automotive engine and if so, what is the cost. If I ran the compnay, I would not.

If have been to a thousand airports across the US, Canada, Bahamas, Alaska, and I recall only a handfull that had mogas. The ones that did were no big savings.

You should consider resale value. I personally know 3 builders just in my town that installed auto conversion engines only to abandom them after a couple years of frustration. They then installed Lycs. I would tell anyone asking my advice (built two) to never buy an auto conversion.
What an interesting perspective. I personally know one builder (me) who used a corvair engine in their airplane. It was a fun build and the airplane flew well. I then sold it for a fair price to another who continues to enjoy it many years later! Crazy.

Insurance: I’ve built a few experimental airplanes - I’ve not yet been asked by the insurer which engine my airplane has. I put this myth in the same box with the one about insurers denying claims because the engine was over TBO (certified aircraft).

Gas: I fly my airplane almost daily and buy fuel at the local station and then just fuel my airplane from my truck. I’m not sure why fuel type is that relavent to lycoming versus automotive based engines considering you can run mogas in many Lycs, but being able to burn mogas as well as avgas adds options, and it certainly saves me money (as in more than $1 per gallon compared to the 100LL at the airport) in addition to not having to deal with leaded fuel.

Resale: I don’t really care. I built (and am building again) for myself. If my airplane is worth 20% less than a comparable one built exactly to Van’s plans, so be it. I will likely have spent even less building it and enjoyed it either way.

There are always naysayers, but fortunately we still have a little freedom left to choose how we want build our own airplanes.

My advice is to build it the way you want and enjoy it.
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- RV10, N1530G (reserved). Empennage in progress.
- RV12, N975G, Flying

Last edited by rongawer : Yesterday at 11:22 PM.
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