A big part of this reliability is due to the fact that engine manufacturers have set standards for the parts used in the engines, the acceptable condition of those parts and the method used to assemble those parts into a complete engine. We will be the first to tell you there are specialty shops that can extract considerably more horsepower than is offered in a stock aircraft engine. High compression pistons, special profile camshafts and custom machine work in the combustion chamber and valve areas can produce significant horsepower gains.
Some of the hottest experimental aircraft flying today make use of these modified engines to achieve their incredible performance. First versions may be simple auditory alerts in your headset. This is where the family feud analogy comes full circle in my mind. In the roughly 25 years that the GA community has been trying to find an unleaded alternative to LL avgas, GAMI's new unleaded fuel is the first promising step in the right direction.
Is it OK to use 1 diesel in your engine if Jet A is not available? Technically yes, but there are some gremlins you need to be aware of. This is one of those questions that doesn't have a perfect answer, but don't make the mistake of thinking your aircraft engine is like your car's engine.
Q: I am purchasing a Piper PA that has 1, hours. Should one always rebuild at 2, hours? Any benefit of following with oil samples at changes to get more life from the engine? With your experience I would like your thoughts. If I did my math correctly, this engine has been operated approximately 38 hours, on average per year, during the 47 calendar years of its life. That leads me to believe this engine has suffered several periods of extended inactivity, which is detrimental to the engine from the standpoint of internal corrosion taking place.
Conducting a thorough borescope inspection of all cylinders would be highly recommended to look for signs of corrosion. I would also recommend you do a very close review of the engine logbooks, paying particular attention to the oil and filter change frequency compared to the actual flying and calendar time.
Also do a close review of the logbooks for general maintenance that has been performed over the life of the engine, such as hot differential compression checks, etc. What is and has been the typical oil consumption between oil changes? My biggest concern regarding this aircraft, as I mentioned earlier, is its age. I would take into consideration when making an offer on this aircraft that you will soon be required to take some type of action regarding the engine.
You have several choices, of course, including a field overhaul where the cylinders could possibly be reworked depending on their condition. If oil analysis has been a routine at every oil change on this engine, then it can be a powerful tool when it comes to assessing the health of the engine.
If the aircraft is put into service and oil analysis is going to be considered, it should be done over a period of several oil and filter changes. This should give us a pretty good baseline to make our comparisons. It could also be an indication of camshaft and tappet wear caused by corrosion. Honestly speaking, you should be prepared to spend some money on the engine in the very near future. Paul McBride , an expert on engines, retired after almost 40 years with Lycoming. Send your questions to askpaul generalaviationnews.
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Helicopter rotor blades also have life limits, and there is a reason. Much as we would like, our engines will not last forever as long as we keep changing the oil.
Personally, I have no problem at all spending some thousands of dollars on preventive maintenance. It is worth it to me simply in peace of mind. It is also worth it to my family, because they have NO idea what makes an airplane fly money , and they have to trust me and trust the equipment literally with their lives. One should collect operational data, then inspect and repair as necessary based on science and data, not superstition.
There are a few things that are life-threatening that are hard to inspect without disassembly, , like magnetos and some Lycoming fuel systems: You need convincing evidence that they have been rebuilt by a reputable agency within a reasonable time frame or hours, especially the two-in-one Bendix -D mag. Too often, maintenance leads to maintenance induced failures -MIFs. Vacuum pumps are an odd case where infant mortality often exceeds old age failures. If you fly IFR than redundancy is the only logical option, but that isn'[t what the writer asked.
The article implies that the engine is a virgin, never touched since it left the factory since , or has it had repairs, inspections and appliance replacements? Is it carbed or FI? Why the concern about honing the cylinders, is it burning or blowing oil? Too many questions, not enough info. The prop as well. Corrosion: Does it live in Seattle or Tucson?
Corrosion for the whole aerospace vehicle is a concern here, not just the noisy end. Negotiate accordingly with an overhaul priced into the purchase. If you get more you win. Fly it like you stole it. You did. ADs against the airframe are equally onerous. Your real concern should be the magnetos, vacuum and fuel system. They can ruin your day. She put a lot of cross-country hours on the plane, both before and after we met, and because of the higher-time engine a first-run factory-new Lycoming , she started regular oil analysis with each oil change.
But with hours, it was only a matter of time before we started seeing signs that it might be getting tired. The fuel pump was telling us something—it was a sign that we might be getting to the end of a great run. With the airplane grounded until I replaced the pump, I ran it up and did the compression checks. Still, it was another sign. I ordered a new fuel pump and steeled myself for the swap. The back of the Lycoming is pretty close to the firewall on the RV-6—not as bad as on our RV-3, but bad enough.
And that, of course, was when we found the cracks in the engine mount. The RV-6 especially early versions is known for experiencing cracks at the lower corners of the engine mounts, right where the gear legs meet the mount and the mount meets the firewall.
Gussets were added to later versions—as they were to the mounts for the RV-7—but this one had never been modified. We check it every year, of course, and had never seen any problems. This year, though, the crack on one side was painfully obvious, and the other showed suspicious bubbling of the paint.
That, of course, meant that the engine needed to come off. I was a bit annoyed that the fuel pump change would have only taken about 10 minutes with the engine hanging from a hook—so there were four hours of pain and scratched hands down the drain.
But that was a much less significant issue to the obvious question—if the engine had to come off anyway, was it time that we go ahead and do the overhaul? The decision to do a major overhaul is a tough one. The most likely cause for a builder to do an overhaul was as a result of buying a used engine that they needed to go through before installing it on their new airframe.
But rare was the case where someone hung a new engine on a homebuilt and flew it for enough hours to reach TBO. The demographics of our sport are such that the average builder aged out before their engine did.
In the case of our RV-6, the airframe has approximately hours total time. The builder put about hours on it, then replaced the engine with a new factory Lycoming as an upgrade that has soldiered on for the last 28 years or so. There have been some interruptions when previous owners let the plane sit for a year or more before selling on to the next owner. But the machine just kept on running happily. We did cover our bases.
After having to reface an exhaust valve on one cylinder, we purchased four new stud assemblies cylinder, piston, rings and valves at a great price and put them on the shelf.
As part of my work in evaluating new avionics , we upgraded the panel to a complete multi-screen EFIS with IFR navigator about six years ago, ending up with the proverbial airplane where the panel was worth more than the airframe.
With too many airplanes—I know that sounds silly, but until you have more than a couple, it is hard to understand—we occasionally talked about selling something.
But each serves a particular purpose, and sentimentality cannot be avoided. I like having another set of eyes look at my work and another brain to bounce ideas off of and solicit advice from. They teach me stuff and I teach them stuff.
Its good to have friends. Wes, I would love for you to buy me a beer some time. I would enjoy the conversation. The issue comes up most often at TBO's versus "as needed. I have no qualms about rebuilding a carburetor, though, since I'm putting a VW engine on my plane!
Used to be a AP could not split the case only an AI, that no longer true? Never was true. I think you are mistaken but it's no matter.
Never is a long time, how far back you going? I rebuilt a VOA1B in , did all the work under his supervision and he signed it off, at that time I am all most certain I was told by the AI that a AP cannot split the case, but again, no matter at this point.
The above excerpt of Part 43, Appendix D was first published in and was in effect in , as it is today. Well maybe.. A certificated mechanic may not exercise the privileges of his certificate and rating unless, within the preceding 24 months— a The Administrator has found that he is able to do that work; or b He has, for at least 6 months— 1 Served as a mechanic under his certificate and rating; 2 Technically supervised other mechanics; 3 Supervised, in an executive capacity, the maintenance or alteration of aircraft; or 4 Been engaged in any combination of paragraph b 1 , 2 , or 3 of this section.
All modifications must be properly documented on a STC or field approval.
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