Well said, Bruce.
----- Original Message -----From: b dSent: Tuesday, November 30, 2010 5:09 PMSubject: Re: Light-Sport Aircraft Yahoo group LSA
There are many interesting factors in this. In flying in rough turbulence a person tends to get used to it and take it with a grain of salt. Then on a calm day a person tends to hear things he never heard before simply because he can. A simple solution to that is to breath deeply and relax and feel confident that your engine is running well and that you can handle anything that come up. I often fly over a mountain range out West in CA in my compute. The Sierra Nevada's where Mt. Whitney resides. The pass I fly through is typically calm until I reach the Mojave desert which is another weather system of it's own. At that interface, there is typically a downdraft which always gets me. By the time I get to it, I have been flying for an hour or so and very relaxed, you know blue skies, clear air and so on. However if you see the area when it has clouds, it is like a water falls spilling over the mountains onto the desert. It always seems to sneak up on me and startle the pants off me as if the wings just fell off. If, on the other hand, the weather had been turbulent, it is be no big deal. It's the idea of going from floating on a cloud to falling off the cloud that always gets me and pumps my adrenalin.In a nutshell, we can become to sensitive to our engine noises on nice days. Good luck, it sounds like you did the right thing by getting a second opinion. Now just relax and enjoy, it won't fall out of the sky and if it does . . . what a way to go!BruceOn Tue, Nov 30, 2010 at 12:43 PM, Bill Hobson <wrhobson@aol.com> wrote:
Thanks for all the ideas. I took my A&P up yesterday (he has a 152 with the same engine) and he didn't think the vibration was anything out of the ordinary. Of, course it was a different kind of day with a bumpy ride and it was hard to tell if it was doing it as "hard" as it was the other day. (Your note on adrenalin may be apropos. I was flying over a large area of marsh grass and mud.) I guess all I can do is continue to be alert for any more odd sounds/sensations. I haven't noticed any issues during climb or descent and your thought on leaning might also be involved. (I typically don't lean until I'm at my cruising altitude and have pulled the power back to around 2700 rpm.) It may, in fact, be a bit of pre-ignition on one of the cylinders as when it was doing it the other day it was almost like I could "feel" each power stroke on one of the cylinders.Sent: Monday, November 29, 2010 10:24 PMSubject: Re: Light-Sport Aircraft Yahoo group LSA
Bill,
- Could it be valve springs? - does it happen like the first flight of the day and then not again? In other words after your engine has set overnight kinda like a tire might develop a flat spot over night? Valve springs are weird, they typically only bounce in flight and on the first flight of the day if they are going to harmonize or bounce. I know I had to change all the valve springs on a piper twin Seneca years ago (recommended by the factory). That caused me to build a very slick tool that allowed me to change the springs in about 25% of the normal time.
- Could it be a lifter issue?
- Could it be a lean mixture? causing preignition on some but not all cylinders, especially noticed on climb out. I once got to altitude, leaned my little 150 out . . . to climb over some mountains ahead, I added a little more power to climb. BAM! It scared the bejesus out of me. I thought the engine blew up. It was only a lean mixture but it got my attention.
- Adrenalin can be a real factor too. Especially at night and over water or over forests with no bare spots to land. One can almost hear the parts wearing. :-) Been there and done that too.
- Don't rule out loose baffling or flapping tin somewhere or an embarrassing seat belt hanging out the door. Once I had to chase a friend down the runway in my car to tell him his baggage door was still open. I didn't have a radio and ge would have lost most of his gear he had stowed.
- "sloppiness" in the connecting rod or wrist-pin bearings - These, I think, are not very likely because if they were that bad, you would hear them all the time after the engine has come up to temp.
Each thing should be ruled out, easiest ones first. Try to force the event to happen, don't shy away from it. The pattern is a good place to have a failure if you are going to have one. The worst type of problem is an intermittent problem where one cannot predict it and isolate it. If you can make the event happen predictably, then you can run tests to see what amplifies it and what attenuates it. In the old TTL or transistor transistor logic, you could feel components with your finger to feel for excessive heat and then you could force them to breakdown by adding so external heat from a soldering iron. Other parts you could cool with a hairdryer without heat and this may resurrect. Do you have temp monitor on all four cylinders? That could tell you something.Remember, doing and overhaul is one thing. Doing an overhaul with a know issue and then finding out you didn't cure the issue is "maddening". Try to identify, isolate and eliminate the issue before you ever tear it down. Don't just "hope" the overhaul catches it.BruceOn Sun, Nov 28, 2010 at 7:01 AM, Bill Hobson <wrhobson@aol.com> wrote:
Roger: I noticed you mentioned that you are an A&P. It seems to me that my engine (a Lycoming O235-N2C) sometimes exhibits a rapid "hammering" sound in the 2600-2700 rpm range. (Or, it may just be the "biting" of the prop in the oncoming air stream.) This usually happens when it is severe clear, no traffic in the area, living-room chair smooth and little radio activity so maybe its just the result of an overactive imagination. (We need SOMETHING to worry about at all times, don't we?) I'm approaching annual time and wondered if there was any kind of test (short of a tear-down) that can evaluate any developing "sloppiness" in the connecting rod or wrist-pin bearings. (If these automotive terms have a corresponding airplane engine application.) Do you know of any such test or equipment that can do that?Sent: Sunday, November 28, 2010 2:54 AMSubject: Re: Light-Sport Aircraft Yahoo group LSA
I should learn to proof read before hitting send. What should have been said is that we are not all UL pilots transitioning to Sport. I have 1,000 in GA planes as well as an A&P license. Right now I work and fly on light sport planes. They fill the need to fly and not spend a bunch of money. Checking in on type specific sites is the best way to go if you are interested in a particular type. Take care. Roger P
From: Roger Poyner <rogpoyn@yahoo.com>Sent: Sat, November 27, 2010 11:25:16 PMSubject: Re: Light-Sport Aircraft Yahoo group LSA
All of us in the group are transitioning UL pilots. I started with ULs but have a bit of GA background. The sport side fits most of my flying desires and is a bit simpler. Roger P
From: "peppypilot@gmail.com" <peppypilot@gmail.com>Sent: Sat, November 27, 2010 10:37:28 PMSubject: Re: Light-Sport Aircraft Yahoo group LSA
Thanks. That's where I am cruising now.Lots to learn. Glad I am starting early.Sent with Thanksgiving greetingsfrom my iPhone
Hello if you want information on specific complying standard category aircraft ask on the relevant forums There will be lots more information available.PeterSubject: Light-Sport Aircraft Yahoo group LSADate: Sunday, November 28, 2010, 2:25 PMThanks for the reply. I have a current medical and have never been denied. If I purchase a LSA, I may keep my medical current. All of this is just part of a prospective pre-buy thought process. I might go back to a standard certicated aircraft. Maybe experimental. At my age, 63, I've started to collect friends embroiled in expensive and time-consuming medical paper-shuffles. Most of my flying is by myself or with my wife, day vfr, so I am thinking about getting ahead of that curve.Sent with Thanksgiving greetingsfrom my iPhone.Be careful about the medical. If ever denied a medical, it exempts you from the LSP program.
On Sat, Nov 27, 2010 at 5:16 PM, Cathy and Joe <peppypilot@gmail.com> wrote:Geetings all!I am a brand new member and hope I am in the right place.I have been an intrument rated private pilot SEL for 28 years and former owner of a Cherokee 140. I am thinking of jumping back into ownership, but at my age, would prefer a LSA to avoid the medical bureaucray of the FAA should a medical condition develop. Most of my flying nowadays is day vfr with my wife or a buddy anyway, so not much to be lost.Legacy aircraft seem to include Luscomb, Ercoupe, Aeronca, Taylorcraft and Piper Cubs.I am hoping this group has some experience with these aircraft and/or can point me in the right direction.Thanks,Joe------------------------------------Yahoo! Groups Links<*> To visit your group on the web, go to:<*> Your email settings:Individual Email | Traditional<*> To change settings online go to:(Yahoo! ID required)<*> To change settings via email:<*> To unsubscribe from this group, send an email to:<*> Your use of Yahoo! Groups is subject to:--*No trees were killed in the sending of this message, but a large number ofelectrons were terribly inconvenienced*
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