You're inserting hard returns, it's best to let the forum handle word wrap. inserting returns makes your writing very, very, hard to read,
ekirkimbo said:Turd, your reply is a perfect example of what this thread was an example of, well meaning persons who turn people away from the automotive engines by spreading misinformation. First, let me clarify the fact that many conversions can prove to be time consuming. They can also be simple and they can also prove to be more efficient, more economical over time, smoother, more powerful, and even more fun. Anyone with a conversion will probably attest to the satisfaction of having done it themselves. One thing you must accept is that only certain homebuilt airplanes have established common solutions to the problems all home builts present. Most certainly, Vans has such a large following that there is virtually no component you can't purchase rather than build, and no problem that a solution hasn't been found. When you step away from Vans though, its pretty much getting back to having problems and finding solutions on most other homebuilts...especially scratch builds.
While that may be oversimplifying, the actual process is still "easier" than installing a converted auto powerplant (and a minor nit, just because one installs a certified [sic] engine into a homebuilt, does not make it 'formerly' certified [sic] engine)Turd Fergusson said:I'm not biased but I am cognizant of reality. It is "easier" to install a certificated engine because the basic process is "purchase a used engine, mount it in an airplane and bolt a prop to it.
First a builder has to be able to find a prospective engine thats the size and type he wants. Often there are not many available in the builders local area...so he is forced to search the internet, tradeaplane,Ebay, Barnstormers, etc.Eki said:Yes, thats a real over simplification, and thats where it becomes misleading. What you left out is that
Then he must either decide on whether the log book is believeable...if there is a logbook. He must either accept on faith that the seller is honest, or travel to where the engine is located. Most often he will not get to hear the engine run.
"IF" an available engine is well documented and reasonably low time, he should expect to pay a premium price to get it.
If the engine is missing documentation he should still expect to pay dearly for it. Once he has that engine in his posession, if it does run properly and have no problems (the exception), he should realize that he should check all the ADs for the engine and insure they were complied with. Often, they haven't been. He may not be legally required to comply with them in an experimental, but since its his butt is on the line it would be wise to do so. ($$$$). He should then hire ($$$$) an AP to physically inspect the engine. Lets say all went perfectly to this point. Now the new builder should expect to have the engine inspected ($$$$) yearly if he wants to maintain its reliability. He should also expect to pay a lot more for aviation oil that has to be added regularly, and aviation fuel. In the likely event that he flies the engine for several years he should also expect to replace at least one cylinder ($$$$) before it reaches TBO. "IF" he does reach TBO he should then expect to lay out somewhere in the neighborhood of the original used engine cost to rebuild it.($$$$$$$$)
The builder is usually not looking at the big picture, because its so easy to just "plug n play"......or is it.
Lets think about that. Any engine you install is going to have to have similar controls and systems to operate properly. Depending on the type of systems you employ, they can often be simple or complex....builders choice.
All engines are going to require an exhaust system. Will it be any more difficult to make an exhaust for an auto engine than an aero engine. Nope. TOSS UP
What about the fuel system ? well if you use a carburetor it should be about the same level of difficulty. If he decides to use fuel injection it will be more complex but will result in greater efficiency and smoothness and no carb icing.
TOSS UP with Carb HARDER With Injection (but better result when finished)
Motormount...here again, the difference in building one or the other is a moot point. The aero engine can actualy be more difficult because of the special mounting. In all but the most popular kits a builder should expect to build his own.
TOSS UP (Maybe a slight edge to auto engine because of no complex dynafocal alignment)
Cooling System Here again, the builder will be faced with cobbling up something and making it work. It is not a given that all aircooled engines will automatically cool well. The inference is that water cooling can be more difficult. Air cooling often does not work and builders spend equal amounts of time trying to cool their engines...sometimes damaging their engines before successful airflow is achieved.
TOSS UP (Maybe an edge to the aero engines because some do cool without problems but you will have to experiment with many air cooled installations to get sufficient cooling. The water cooling will work better if done properly....no shock cooling probs or cht probs to ferret out later)
Weight Generally the auto will weigh more but it depends on the airplane and engine of choice. The alum V8 really starts to shine when compared to the larger and exceedingly expensive aero engines. As you move to smaller airplanes the reduction drives might be eliminated and direct drive used to keep weight down. LS engines are cheap, Rover engines even cheaper and then there are some nice V6s available too.
TOSS UP I say this because the auto engines will always be heavier in smaller airplanes but they are generally capable of more power .....thru increased rpms.... to help offset the weight. I give a slight edge to the aero engine strickly on weight.
Ignition System Both types of engines are going to have to have some type of ignition system. Many/most builders are going to have an electrical system of some kind. Even if you have magnetos on the aero engine the builder wiill also fabricate an electrical system. Is adding a modern multicoil ignition that comes with the auto engine going to be any more difficult than building the rest of the electrical system ? Many builders add electronic ignition to their aero engines anyway. TOSS UP
The Bugaboo This is where the aero engine has the advantage. Adapting a prop to the engine. With the aero engine you certainly can just bolt a prop on to it as long as you have enough money. Just remember that if you install one which is not the one the factory recommended , you have changed the resonanant frequency and no longer know where it exists, or to what magnitude it may be. That affects reliability. Yes you can test other props, but thats the same situation you have with the auto engine. So prop testing and mounting should ensue.
So Turd, this reply is a real world explanation of "just bolt it on and go flying" . There is a big difference between buying a new discounted Lycoming for a Vans kit and buying a questionable used engine to install in a plans only homebuilt.
The statement that its much more difficult to use an auto engine is sometimes true, but since building an airplane requires fabrication of mostly the same components, I think its often overstated. To me the only real difference and difficulty is how to adapt the propellor to the crankshaft. I feel the 5th bearing idea is reasonably easy for someone to do. It would be great if someone made a universal 5th bearing and only an adapter plate was needed to utilize it on various engines.
I still believe that technology is not the biggest impediment to auto conversion success, its the negativity continually espoused by air cooled engine purists and the oft mis-stated "plug n play" scenario.
I would also like to agree with your statement that " many people are not interested in developing a converted powerplant", but I hate to think that reason is because they have been misled about the difficulty of one vs the butter smooth ease of the other.
As for a certified engine maintaining its certification after its installed on an experimental airplane, my understanding is that it loses its certified status. Maybe there is an exception to the rule, but thats how I understand it.