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#21
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Maule Driver wrote:
: As a recreational pilot of a simple IFR aircraft, I've recently : discovered a great role for the T&B; staying on heading. After a few : years of struggling to keep my non-AP equipped flivver on a MH, I've : re-discovered what many must know. The T&B is the best instrument to go : straight with. The AI gives you good info, and the heading gyro does : too, but the best way to keep it all centered in my Maule is definitely : the T&B. Especially in calm conditions. I don't know if I'll agree with that. Once you dial in your wind correction angle, the DG is the primary instrument for bank in straight-level flying. When I was working on the instrument written, I tried to find easy ways to remember primary vs supporting instruments for different stages of flight. One of my conclusions was that for long-term accuracy, the instruments that provide the integral of the chosen parameter are the most accurate, and thus "primary." For instance, the result of a pitch change integrated gives you altitude, so it's primary for straight-level. The result of a bank change integrated yields a heading, so the DG is primary. The trouble with direct-read indications is that they are not accurate enough for long-term useage. The AI is good for radical attitude changes, but you cannot see a 1/10 stdrad turn on either it or the T&B/TC. You *will* see it on the DG as the numbers slows roll by. Of course, to each their own. Just so long as you keep the shiny-side up!... -Cory ************************************************** *********************** * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * ************************************************** *********************** |
#22
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#23
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Mark Hansen wrote:
: I've done what Maule Driver is talking about, and think of it rather : like using the VSI to assist in maintaining altitude. I use the VSI : to give me an indication that an altitude change is coming, and I need : to anticipate it and correct (the VSI doesn't react all that quickly, : but still...) : If I do this right, I never see the altitude change. Of course, : this doesn't change the fact that the altimeter is the primary pitch : instrument - it's just not the only pitch instrument. : So ... I do the same with the T&B giving me an indication that a turn : is coming, and I can anticipate it and react. The DG is still the final : authority as to whether or not you're heading in the right direction, but : I think it's better to keep it on the heading, rather than notice it's : not and having to correct (when the turbulence allows, of course ;-) ) Sure... they're all related of course. I guess the point I was trying to make is that (barring turbulence), I don't *see* a change in VSI/AI/T&B in straight/level cruise. A certain amount of pressure on the controls will fix small errors in DG/ALT. Those are typical in non-turbulent flight, and there will be no perceptible indication from the VSI/AI/T&B. For anything other than a minute change (e.g. turbulence) the other indicators are better and then line up on the "primaries" (DG/ALT). Like I said... to each their own. Probably saying the same thing anyway... -Cory -- ************************************************** *********************** * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * ************************************************** *********************** |
#24
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Its a good idea if you can't afford a standby electric attitude
indicator. I've had more indicators fail then pumps myself. -Robert |
#25
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If your attitude indicator fails and you have a back up, you just look
at the other attitude indicator (this is what the airlines and military teach). If your attitude indicator fails and you have precise flight, you learn to fly with the turn coordinator alone. -Robert |
#26
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Peter R. wrote:
Michael wrote: I think that if you really feel the need for redundancy, the sensible solution is replacing the T&B with an electric AI. I see that Sporty's is encouraging this option, too, with their electric AI. However, doesn't the AI have the potential to tumble in an unusual attitude? During my IFR training I recall learning that the turn coordinator will not tumble in an unusual attitude scenario whereas the AI may. Since recovery from an unusual attitude was taught to me by first going to the TC, I would be hesitant to replace an instrument so reliable during a UA. What say you? Vacuums tumble. Saw it on Dave Letterman, "throwing household appliances off a building". |
#27
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Peter R. wrote:
Michael wrote: I see little chance of that happening with dual AI's, and even less chance that the average pilot will recover from an aerobatic attitude partial panel after screwing up enough to get into that mess. Interesting that you pointed that out. I was thinking the same thing when I posed the question but thought that two tumbling AIs would pretty much guarantee that the pilot would not recover. But hey - if you have the panel room, why not keep the electric TC too? My Bonanza has the original TC along with a backup electric AI located to the left of the TC. However, the electric AI keeps precessing and requires a reset about four times per hour, which concerns me. What brand ? |
#28
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Stubby wrote:
Scott Moore wrote: Mitty wrote: Our club is looking at upgrading a couple of airplanes to Garmin 430s, etc. It seems to me that standby vacuum would be a good thing to add, too. 1) Good idea? Do these systems really work? 2) Recommendations on type/brand/model? TIA Electric attitude. Vacuum pumps are going away. But, can't an electric attitude indicator fail? Bearings wear out. I've suffered that on a hard disk. Are there any MTBF numbers for the two systems? I have heard that EAIs have better fail numbers than vac, but sure, its nonzero. The reason why all electric panels are becoming common is because electrical systems are more reliable than vacuum, and backup is easier to provide for everything, a second battery. It also makes more sense to unify around a single system, instead of having a hodge-podge of two different systems. I would go all electric and remove my vac pump, but I blew it and got an NSD-360. The first repair bill for that utter piece of defective junk easily pushed the total cost above what an all electric solution would have cost (i.e., $5000 for the NSD360, and $4000 to get it to work correctly). |
#29
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#30
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Peter wrote:
: It took me a while to work out what the FAA was looking for in the IR : written, on "primary" and "supporting". It's easy enough in straight : and level flight, but on stuff like a transition from a stabilised : level turn to a climbing constant-speed turn, it's very hard to get : one's head around it. Luckily, I passed, and one has to learn these : word tricks only once : Yeah, me too... that's why I came up with what I did (in my own mind, anyway). Basically, it was something like: attitude = rate = result So, during the phases of flight while you are transitioning, the attitude is generally the most important. Holding rates (CR climb, SR turn, etc) it's rate-based like VSI or TC. Result is the integral thing. Anyway, I agree... I passed and now you just need to know how to do it, not some cryptic wordplay to pass an exam. -Cory ************************************************** *********************** * Cory Papenfuss * * Electrical Engineering candidate Ph.D. graduate student * * Virginia Polytechnic Institute and State University * ************************************************** *********************** |
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