If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
an interesting in flight experiment
On Oct 18, 12:02*pm, Frank Stutzman wrote:
a wrote: In my case the engine ran a bit rougher -- rpms stayed where they were set, of course, because prop pitch changed to accommodate the reduction in power. And if you were flying a 6 cylinder (or larger) engine, you may not have even noticed the roughness. * (I once failed to get the switch back to "both" after a run-up. *Managed to take-off and fly for ~15 minutes before I noticed it. *The roughness became more pronounced when I started leaning it out). -- Frank Stutzman Bonanza N494B * * "Hula Girl" Boise, ID The IO 360 has 4 cylinders -- the roughness was not really bad, and you could be right -- with 6 may not have been noticeable. My hand stays on the mag switch throughout a mag check so I want to believe I won't forget to go back to both -- help us avoid making your mistake: do you remember what distracted you enough to leave it pointing to a single bank of plugs? |
#12
|
|||
|
|||
an interesting in flight experiment
"a" wrote in message ... My hand stays on the mag switch throughout a mag check so I want to believe I won't forget to go back to both -- help us avoid making your mistake: do you remember what distracted you enough to leave it pointing to a single bank of plugs? I agree, no reason to take your hand off the switch, but things can still go wrong! I also took off on one mag once. I don't think I actually forgot to return the switch to "both", but just made a sloppy job of it and somehow ended up with the switch not quite in the detent. I still kick myself for not aborting that takeoff. It turned out to be a butt-puckering trip around the patch. I never did make it alll the way up to pattern height. Now I visually verify the position of the switch before leaving the runup pad. Lesson learned! Vaughn |
#13
|
|||
|
|||
an interesting in flight experiment
On Oct 18, 2:24*pm, "vaughn"
wrote: "a" wrote in message ... My hand stays on the mag switch throughout a mag check so I want to believe I won't forget to go back to both -- help us avoid making your mistake: do you remember what distracted you enough to leave it pointing to a single bank of plugs? I agree, no reason to take your hand off the switch, but things can still go wrong! *I also took off on one mag once. *I don't think I actually forgot to return the switch to "both", but just made a sloppy job of it and somehow ended up with the switch not quite in the detent. *I still kick myself for not aborting that takeoff. *It turned out to be a butt-puckering trip around the patch. *I never did make it alll the way up to pattern height. Now I visually verify the position of the switch before leaving the runup pad. Lesson learned! Vaughn That's interesting. My primary flight instructor must have been burned by something like that, because my training (which did not include getting rapped across the knuckles with a stick -- that was from grade school days) was to focus on the tach, go from both to left, note the drop, back to both, see the tach get back to 1900, go to right, note the drop, go to both, see the tach get back to 1900, and only then let go of the mag switch. He was the same guy who insisted controls like throttle and mixture should be pushed with the palm, pulled with curled fingers, and never grasped-- his point was that if can can only push or pull you are less apt to move something in the wrong direction. Some old habits are worth retaining. If he could have he would have replaced radio tuning knobs with paddles. Would you say he was compulsive? |
#14
|
|||
|
|||
an interesting in flight experiment
On Sun, 18 Oct 2009 12:48:26 -0700 (PDT), a wrote:
On Oct 18, 2:24*pm, "vaughn" wrote: "a" wrote in message ... My hand stays on the mag switch throughout a mag check so I want to believe I won't forget to go back to both -- help us avoid making your mistake: do you remember what distracted you enough to leave it pointing to a single bank of plugs? I agree, no reason to take your hand off the switch, but things can still go wrong! *I also took off on one mag once. *I don't think I actually forgot to return the switch to "both", but just made a sloppy job of it and somehow ended up with the switch not quite in the detent. *I still kick myself for not aborting that takeoff. *It turned out to be a butt-puckering trip around the patch. *I never did make it alll the way up to pattern height. Now I visually verify the position of the switch before leaving the runup pad. Lesson learned! Vaughn That's interesting. My primary flight instructor must have been burned by something like that, because my training (which did not include getting rapped across the knuckles with a stick -- that was from grade school days) was to focus on the tach, go from both to left, note the drop, back to both, see the tach get back to 1900, go to right, note the drop, go to both, see the tach get back to 1900, and only then let go of the mag switch. He was the same guy who insisted controls like throttle and mixture should be pushed with the palm, pulled with curled fingers, and never grasped-- his point was that if can can only push or pull you are less apt to move something in the wrong direction. Some old habits are worth retaining. If he could have he would have replaced radio tuning knobs with paddles. Would you say he was compulsive? No but he had a feckin' moron for a student. |
#15
|
|||
|
|||
an interesting in flight experiment
"a" wrote in message ... Would you say he was compulsive? Perhaps he just had a will to live? Back in my sailplane instructing days, I taught my students to not wrap their fingers around certain controls, particularly on takeoff. Reason? A jolt (we took off on grass) could make you accidently pull a control. That could disconnect you from the towplane if you pulled the release (the same as your engine quitting on takeoff) or...if you accidently pulled the spoilers open, our towplane would no longer be powerful enough to keep us flying. Vaughn |
#16
|
|||
|
|||
an interesting in flight experiment
On Oct 18, 5:18*pm, Franklin "Franklin
wrote: On Sun, 18 Oct 2009 12:48:26 -0700 (PDT), a wrote: On Oct 18, 2:24*pm, "vaughn" wrote: "a" wrote in message .... My hand stays on the mag switch throughout a mag check so I want to believe I won't forget to go back to both -- help us avoid making your mistake: do you remember what distracted you enough to leave it pointing to a single bank of plugs? I agree, no reason to take your hand off the switch, but things can still go wrong! *I also took off on one mag once. *I don't think I actually forgot to return the switch to "both", but just made a sloppy job of it and somehow ended up with the switch not quite in the detent. *I still kick myself for not aborting that takeoff. *It turned out to be a butt-puckering trip around the patch. *I never did make it alll the way up to pattern height. Now I visually verify the position of the switch before leaving the runup pad. Lesson learned! Vaughn That's interesting. My primary flight instructor must have been burned by something like that, because my training (which did not include getting rapped across the knuckles with a stick -- that was from grade school days) was to focus on the tach, go from both to left, note the drop, back to both, see the tach get back to 1900, go to right, note the drop, go to both, see the tach get back to 1900, and only then let go of the mag switch. He was the same guy who insisted controls like throttle and mixture should be pushed with the palm, pulled with curled fingers, and never grasped-- his point was that if can can only push or pull you are less apt to move something in the wrong direction. Some old habits are worth retaining. If he could have he would have replaced radio tuning knobs with paddles. Would you say he was compulsive? No but he had a feckin' moron for a student. Thanks so much for your insight. So far his moronic student had 3000 safe odd hours in a complex single, so his instruction worked. You, on the other hand -- your remark is the QED of that -- clearly failed in social skills.. |
#17
|
|||
|
|||
an interesting in flight experiment
On Oct 18, 5:22*pm, "vaughn"
wrote: "a" wrote in message ... Would you say he was compulsive? Perhaps he just had a will to live? *Back in my sailplane instructing days, I taught my students to not wrap their fingers around certain controls, particularly on takeoff. *Reason? *A jolt (we took off on grass) could make you accidently pull a control. *That could disconnect you from the towplane if you pulled the release (the same as your engine quitting on takeoff) or...if you accidently pulled the spoilers open, our towplane would no longer be powerful enough to keep us flying. Vaughn Good habits are often validated in the real world. I doubt that things like pushing with palm, pulling with fingertips, have saved lives, but the ingraining of bits and pieces like those in total probably do. That old saw -- a superior pilot uses superior judgement to avoid circumstances where he (or she) has to use his (or her) superior skills really is true. |
#18
|
|||
|
|||
an interesting in flight experiment
"a" wrote in message
... On Oct 18, 10:40 am, "Peter Dohm" wrote: "Morgans" wrote in message ... "twdeckard" wrote I am sure you know all of this (grin), I just chimed in becuase its a check best done on the run-up pad. He did not say you shouldn't do it at run-up. He was just pointing out that your engine could run very rough if you lose one side while cruising. -- Jim in NC I am really not sure exactly what he tried to say; but, in his initial post, it was clear that he had lost the use of all of one mag and a part of the other--or the plugs or wires attached to it. The problem with that is that mags have a couple of failure modes that are common to all breaker point ignition systems in addition to the failure modes that are peculiar to magnetos. As far as I know, it is still a common practice to simply set the timing and perform a runup type mag check as part of an annual and not open the mags to gap and visually check the points. That leaves the door a lot farther open for the failure modes involving erosion of the points--which is related to one of the two failure modes of the capacitor a/k/a condenser--and also to wear of the cam follower. Both of those failure modes usually make the engine harder to start long before they will fail in flight, or at runup test; but are masked sufficiently by electric starters that they can go virtually unnoticed--unless the pilot is so dilligent as to carefully prime and set the throttle and then count the blades on nearly every start. Peter To put several of your minds at ease, of course I did the conventional both-right-both-left mag check at runup, but at 1900 RPM. I had not had one bank of spark plugs go in/op ever until the in flight failure a little while ago, and my post was simply to suggest pilots go to one mag while at cruise rpm and engine loading to see what happens. In my case the engine ran a bit rougher -- rpms stayed where they were set, of course, because prop pitch changed to accommodate the reduction in power. I am sure I make lots of inadvertent errors when flying: missing a mag check is not one of them. I was not trying to suggest that you failed to check the mags prior to takeoff, and I do not have an opinion as to whether an in-flight check would necessarily tell anything of value. The problem that I have personally observed was a case of points which had gradually "closed up" on a 65 horsepower Piper Cub until the engine could not be manually started--and then was started on the first "lave" pull after the points had been dressed and gapped. A second case, that was only confirmed much later, involved a Cessna 172 which occasionally required manual starting for an assortment of stupid reasons; but started very reluctantly in those instances... The salient point is that both aircraft passed all tests normally available to a pilot; but, based upon the number of hours that each was operated, probably had one or both mags out internal tolerances for multiple years. So there are failure modes that the pilot can not necessarily overcome--including damaged insulation on a p-lead, or a shorted mag switch, amoung others. By the way, what were the problems later identified on your aircraft? Peter |
#19
|
|||
|
|||
an interesting in flight experiment
a wrote:
.... Even on run up you lose some RPMs when on a single bank of spark plugs. Usually. At a 1700 rpm run up this morning, - I couldn't find a drop either side. So I did a dead cut (at 1200rpm) with the usual effect. Brian W |
#20
|
|||
|
|||
an interesting in flight experiment
On Oct 18, 6:39*pm, "Peter Dohm" wrote:
"a" wrote in message ... On Oct 18, 10:40 am, "Peter Dohm" wrote: "Morgans" wrote in message ... "twdeckard" wrote I am sure you know all of this (grin), I just chimed in becuase its a check best done on the run-up pad. He did not say you shouldn't do it at run-up. He was just pointing out that your engine could run very rough if you lose one side while cruising. -- Jim in NC I am really not sure exactly what he tried to say; but, in his initial post, it was clear that he had lost the use of all of one mag and a part of the other--or the plugs or wires attached to it. The problem with that is that mags have a couple of failure modes that are common to all breaker point ignition systems in addition to the failure modes that are peculiar to magnetos. As far as I know, it is still a common practice to simply set the timing and perform a runup type mag check as part of an annual and not open the mags to gap and visually check the points. That leaves the door a lot farther open for the failure modes involving erosion of the points--which is related to one of the two failure modes of the capacitor a/k/a condenser--and also to wear of the cam follower. Both of those failure modes usually make the engine harder to start long before they will fail in flight, or at runup test; but are masked sufficiently by electric starters that they can go virtually unnoticed--unless the pilot is so dilligent as to carefully prime and set the throttle and then count the blades on nearly every start. Peter To put several of your minds at ease, of course I did the conventional both-right-both-left mag check at runup, but at 1900 RPM. I had not had one bank of spark plugs go in/op ever until the in flight failure a little while ago, and my post was simply to suggest pilots go to one mag while at cruise rpm and engine loading to see what happens. In my case the engine ran a bit rougher -- rpms stayed where they were set, of course, because prop pitch changed to accommodate the reduction in power. I am sure I make lots of inadvertent errors when flying: missing a mag check is not one of them. I was not trying to suggest that you failed to check the mags prior to takeoff, and I do not have an opinion as to whether an in-flight check would necessarily tell anything of value. The problem that I have personally observed was a case of points which had gradually "closed up" on a 65 horsepower Piper Cub until the engine could not be manually started--and then was started on the first "lave" pull after the points had been dressed and gapped. *A second case, that was only confirmed much later, involved a Cessna 172 which occasionally required manual starting for an assortment of stupid reasons; but started very reluctantly in those instances... The salient point is that both aircraft passed all tests normally available to a pilot; but, based upon the number of hours that each was operated, probably had one or both mags out internal tolerances for multiple years. So there are failure modes that the pilot can not necessarily overcome--including damaged insulation on a p-lead, or a shorted mag switch, amoung others. By the way, what were the problems later identified on your aircraft? Peter My in-flight check in fact produced something of value, Peter. The engine in cruise went a little rough and stayed that way with mixture adjustments. When I went to a single bank of spark plugs the engine noise went from rough to none: I was flying on half the spark plugs. That told me two things -- to land for a repair, and what to tell the A&E. My suggestion in the OP was that pilots learn what their engine does when on a single bank of plugs when at cruise. It might be instructive, it might not be. The failure mode I experienced was in the high voltage lead between the magneto and the distributer. The voltage impulse found a gap more convenient than the one at the spark plugs, this on an engine that was only about 1100 hours (on a 2000 hour engine) since last major overhaul. I continued on my trip in less than 2 hours. Clearly the aviation gods smiled on me. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Interesting and different flight on OLC | Dave Nadler | Soaring | 2 | August 4th 09 01:06 PM |
Solar Flight Much more interesting than Hilarious Video | Richard[_1_] | Soaring | 0 | December 5th 08 04:07 PM |
Interesting 2-plane takeoff at BWI 4-28-06 (formation flight) | Gary G | General Aviation | 2 | May 1st 06 08:42 PM |
An interesting trial flight attempt... | [email protected] | Soaring | 35 | February 12th 06 07:31 PM |
A small experiment | Mike Borgelt | Soaring | 16 | May 6th 05 06:41 AM |