If you bring the aircraft back to a hover----and the ASI is still indicating 100kts, one can assume that it is inoperative. ::whistle:: ::whistle::
Me thinks that if you do that with a proper flying machine then the ASI soon won't be the only thing that'll be inop! :D
Gil: Another lady pilot? 8) |:)\
Frank
Title: Re: ASI
Post by: Mike on March 19, 2008, 05:50:17 AM
we should give him a REAL answer at some point I think . . . That was the initial intent of this thread.
Only, I don't have a clue if I could explain that..... any stuck-wing guys left in here??
Title: Re: ASI
Post by: Franz on March 19, 2008, 10:40:17 AM
In gliders you try to avoid using the ASI, because of the lag. What you do is you look at the horizon and try to figure out how fast you're going. If you don't see it at all, you're either pretty fast (houses getting bigger) or way too slow (houses? I can only see sky). And then there's a "normal" position which indicates you're soaring along at a reasonable speed. In planes you'd also have to take engine power into consideration, but if the ASI fails, maybe the engine will, too :o ??? ::sweat::
And just in case all my ability to explain things got lost on my first day of Easter holyday, here's a little drawing to illustrate what I just wrote:
Title: Re: ASI
Post by: G-man on March 19, 2008, 03:51:22 PM
we should give him a REAL answer at some point I think . . . That was the initial intent of this thread.
Boring Boring Boring..However you are right..
There are several ways that it could be determined..
1. As above..bring it to a hover. 2. Maintain a constant power setting and then raise the nose for 5 seconds, and lower the nose for 5 seconds. Observe the ASI, if it is working correctly, it should indicate a decrease followed by an increase in airspeed. 3. Maintain a constant attitude and vary the power..observe the ASI..It should vary with the power. 4. Observe the wind..assuming negligible wind..one could fly low over a freeway and time your self between mileage signs. A simple use of mathematics would determine the accuracy of your ASI. 5. Fly formation with another aircraft and compare ASI readings. 6. Ask your instructor--assuming he/she is sitting next to you. 7. Observe indications on your altimeter and VSI. They all use the same static feed. If they are reading INCORRECTLY, then you can assume that your ASI would also be reading incorrect. 8. Land at an avionics ship and pay copious amounts of hard earned cash to have them run a check. 9. Who needs one anyway..you have a stick shaker warning on the low end and that "wings ripping off" sound on the high end..just fly at a speed between the 2 and you will be fine. ::whistle:: ::whistle::
I rarely use mine so this is about the best I can do.
Title: Re: ASI
Post by: Mike on March 19, 2008, 04:06:21 PM
yeah, Gil ! Why don't you bring her in here? She could ask all kinds of questions (which she may or may not get straight answers for in return ;) ;D ) and I am sure the other girls in here would like to have another girl join.
I sure hope we don't scare off the young aviator people in here..... haven't seen many join lately.... ::thinking::
Title: Re: ASI
Post by: leiafee on March 19, 2008, 06:24:31 PM
Pitch and Power!
I know what airspeed the tommyhawk'll do at various combination of power and nose attitude. If the ASI read significantly different thn I'd wonder about it.
I also have a reasonable "feel" for how the aerplane handles in fast and slow flight -- if it was significantly out, that should be a clue too.
Both of those things came with more practice than I had an a new student pilot though.
Title: Re: ASI
Post by: FlyboyGil on March 19, 2008, 11:07:17 PM
yeah, Gil ! Why don't you bring her in here? She could ask all kinds of questions (which she may or may not get straight answers for in return ;) ;D ) and I am sure the other girls in here would like to have another girl join.
I sure hope we don't scare off the young aviator people in here..... haven't seen many join lately.... ::thinking::
I see she has joined now. She's the newest Member BREISABUTT!!! WELCOME KIMMY!!!!
Title: Re: ASI
Post by: Rooster Cruiser on March 19, 2008, 11:38:55 PM
ASI failures depend on the type of problem encountered. An ASI in fixed wing aircraft measures the relative pressure difference between the Pitot (Ram Air) and Static source, which is measured from alongside the fuselage. If the Static source becomes blocked, the ASI will act like an altimeter. If the Pitot becomes blocked, the ASI will read zero or may show no change in airspeed with changes in attitude or power.
I actually had several ASI failures in my Platypus when I started working here in the desert. The airplane was parked outside under an awning (still is) but it did not have a Pitot cover. Over the months, a bunch of dust gathered into the Pitot. This did not affect my ASI while in flight unless I flew into a cloud at altitude. The moisture in the air would freeze onto the dust, which was insulating the inside of the Pitot tube, rendering Pitot Heat useless. If I was in cloud for more than a minute, I would watch in horror as BOTH my ASI's would wind down and read zero at FL280! I would then have to fly by attitude and power settings only until it became time to descend. Then as I would descend into warmer air, the frost inside the Pitot would melt and my ASI's would once again function normally. My avionics shop finally figured it out much to my relief, but not after I had replaced the Pitot Head and had it happen AGAIN!
RC
Title: Re: ASI
Post by: Mike on March 20, 2008, 12:37:37 AM
hmmmm.... ::thinking::
seems like there is a valuable lesson hidden inside RC's story.... about pitot tube covers and how and when to use them. . .
Title: Re: ASI
Post by: Rooster Cruiser on March 20, 2008, 03:20:50 AM
No kidding Mike. For want of a $200.00 Pitot cover, I spent about $10,000.00 in repairs! ::eek:: ::unbelieveable:: Not to mention the added "Pucker Factor" that went into flying around with a defective ASI... or two! ::banghead::
Title: Re: ASI
Post by: TheSoccerMom on March 20, 2008, 04:58:31 AM
:)
Our covers are free... a side benefit of having an excellent sewer among the pilots... he made a set of perfectly-sized pitot covers for each airplane out of heavy saddle leather.... they don't get brittle in the cold, or too loose in the heat. And one set will last you for years and years.....
The only bad part is that other people have tried to swipe them!! ::complaining:
Title: Re: ASI
Post by: happylanding on March 20, 2008, 06:41:25 PM
I see she has joined now. She's the newest Member BREISABUTT!!! WELCOME KIMMY!!!!
More chicks in the forum! Yeppeeee!
Title: Re: ASI
Post by: BREISABUTT on March 21, 2008, 03:25:14 AM
Hello......I am Kim......the one with the question, AND there will be more questions to come!!! I am a beginner, been a airport brat for awhile but never had the means until now to learn to fly. I will admit I'm being overwelmed by all that that I have to learn on the ground. Seems like lots of math and I'm a math idiot!! I want to thank everyone who has tried to help me, rc you answered my question.
Title: Re: ASI
Post by: Rooster Cruiser on March 21, 2008, 03:52:46 AM
Quote
rc you answered my question.
More than happy to oblige, Kim! Glad to make your acquaintance. What airport are you learning to fly at? FUL, EMT, or POC? In any event, feel free to fire away with questions. If I can't answer it, somebody else probably will be happy to do so. ;)
Title: Re: ASI
Post by: Oddball on March 21, 2008, 07:52:52 AM
you would think as the trainee mech in here iwould contribute to this question......but i wont got home from work and im shattered so sorry cant help you just now :-\
Title: Re: ASI
Post by: TheSoccerMom on March 21, 2008, 06:25:46 PM
Welcome Kim!! How nice to see you in the Coop!!
That's great about your flying... glad to hear you're finally getting to do what you have wanted! ::bow::
Sure hope you will keep asking things, we all get to learn that way. :D
The last Airspeed failure I had was actually because the mechanic had not hooked up the line at ALL.... I got the airplane out of inspection and was hurrying to head for the hills... and he was glad to see me LEAVE, too, of course... but on the takeoff roll, when I glanced to check if "airspeed was alive", it was sitting happily at zero... the thing was, I was empty and so was already airborne! (An empty airplane sure is a nice thing...)
I had a lot of runway ahead and could have landed then, but there was an airliner sitting behind me waiting to get out, so I just came around in the pattern and landed. The mechanic had pretty big eyes when I taxied back in.. "NOW what?!!" was written all over his face......
Like I think Leia mentioned, you get so used to what power setting and which attitude give you what performance, that you will fly the plane at the desired airspeed without having to look at the gauge.... as you go further in your flying, it's good practice to have a CFI cover up the whole panel with a bath towel so you can see this for yourself..... fly where you think you should be, then uncover the airspeed, and Voila... you're right on the speed!
I used to do that with nervous students, or pilots who weren't quite convinced about power + pitch = performance. It gives you a lot of confidence in your airplane, and in yourself, too.
Welcome to the Coop!! ::bow::
Title: Re: ASI
Post by: BREISABUTT on March 24, 2008, 04:47:49 PM
Hi everyone,
I'm back with another question. Spent the whole weekend trying to finishing my homework project, and I was able to anwser all but one question. What are the common potential errors of the turn indicator? I can find anything online or in the books I have................HELP!
Kim
Title: Re: ASI
Post by: TheSoccerMom on March 24, 2008, 04:57:05 PM
Hey there! :)
Do you mean turn indicator? Or turn coordinator?
Do you have a copy of the long-standing FAA Flight Training Handbook? If not I'll send you what it says....
8)
Title: Re: ASI
Post by: Oddball on March 24, 2008, 07:54:57 PM
i suppose if you skid in a turn the indicator will give a wrong reading...dont hold me to that will have to read up on my instruments again
Title: Re: ASI
Post by: airtac on March 24, 2008, 08:50:15 PM
Kim, I'm not sure I understand exactly what you're asking but I'll give it a shot with some generalized information.
First, there's 2 kinds of turn indicators, one is a turn and slip indicator (needle and ball in window) which, because the gyro is mounted horizontally, only senses rotation about the aircrafts vertical axis. When you roll into a turn with this instrument it won't indicate anything until the airplane actually begins turning.
The second type is a turn coordinator (little airplane and ball in window) which has the gyro mounted at about a 30 degree angle from horizontal and thereby indicates BOTH roll and yaw. With this instrument, the little airplane in the window shows the roll into the turn even before the airplane itself begins to turn.
I'm guessing that if the question was asking about error, they might have had that difference in mind. If that's not what you had in mind please feel free to clarify the question.
And don't feel put off if some of our answers seem frivolous----this is a sho-nuff funny bunch of folks here ::loony::
Title: Re: ASI
Post by: FlyboyGil on March 24, 2008, 10:24:15 PM
----this is a sho-nuff funny bunch of folks here ::loony::
That's not true! We're all normal down to earth...........BWA HA HA HA!!!!!!!!! I knew I wouldn't be able to type that!! Yeah we're all nuts ::loony::, but have fun being that way!! ;D ;D ;D ;D
Title: Re: ASI
Post by: Oddball on March 24, 2008, 10:38:59 PM
you have to be slightly nuts to do some thing that is unnatural to us squirels ::loony:: ;)
Title: Re: ASI
Post by: Rooster Cruiser on March 24, 2008, 10:41:23 PM
Kim, turn indicators and turn coordinators do not normally have any problems unless they have no power applied to them. Pehaps you are referring to the gyroscopic precession errors that an Artificial Horizon is subject to? If a pilot in a standard cockpit (Read: NOT Glass Cockpit. I am referring to mechanical gyros in this case) rolls out of a 180 degree turn to wings level based only on the Artificial Horizon, the airplane will actually be banked about 5 degrees or so in the OPPOSITE direction that the turn was done in. This is the point at which the precession error is most pronounced. On a 360 degree turn, the precession error will cancel out during the second half of the turn and the airplane will be wings level if the pilot uses only the artificial horizon to roll out to wings level.
Glass cockpits use laser gyros for their displays which are not subject to precession error.
RC
Title: Re: ASI
Post by: TheSoccerMom on March 24, 2008, 11:47:08 PM
I was waiting to see if Kim had a copy of the Flight Training Handbook, because I am a lazy no-gooder and it takes me forever to type things. But while I'm waiting for the therapist to call, I'll start on what the old book says, for her reference. It's an old book but hey, the air hasn't changed, either.
The turn and slip indicator shows the direction and rate at which the airplane is turning and at the same time whether the airplane is slipping sideward. It is actually a combination of two instruments, a broad needle and a ball. The turn needle depends on gyroscopic properties of precession for its indications and the ball is affected by gravity and centirfugal force.
The turn indicator, being a gyroscopic instrument, indicates the direction and rate at which the airplane is turning about its vertical axis. It responds only to the rate of yaw. (The more modern "turn coordinator" also indicates the rate of roll about the airplane's longitudinal axis since it responds to both roll and yaw.) Unlike the attitude indicator, neither of these instruments gives a direct indication of the degree of bank of the airplane. However, for any given airspeed, there is a definite angle of bank necessary to maintain a coordinated turn at a given rate. The faster the airspeed, the greater the angle of bank required to obtain a given rate of turn. Thus, the turn indicator and the turn coordinator give only an indirect indication of the airplane's banking attitude or angle of bank during a coordinated turn.
That's a LOT of information, in just two paragraphs. The turn indicator is the little stubby needle; the turn coordinator is the little horizontal airplane figure. The turn indicator responds to ONLY the rate of yaw (motion about the vertical axis). The turn coordinator (little plane) responds to rate of YAW, AND rate of ROLL, both (vertical AND longitudinal axes).
And, the little ball sitting in the tiny tube at the bottom of each instrument is the omen, depending on how much you swing it from side to side, on how quickly your passengers will get sick. Ha! ::sick::
Good question, by the way..... ::wave::
8)
Title: Re: ASI
Post by: BREISABUTT on March 25, 2008, 04:56:14 AM
Hi, thanks again for all the help!!!!! Soccormom, no I do not have the FAA handbook, the books I've been using are Gleim's Instrument Pilot, Gleim's Private Pilot, and ASA From the Ground Up. Anything else would be another big help. The home work question were for the six pack instruments, Airspeed Indicator, Attitude Indicator, Altimeter, Vertical Speed Indicator, Directional Gyro,Turn Coordinator. I have to answer the same 6 questions for each one of those instruments.
Here are the question: 1- Generally, How does the insrument work and what is it's power source? 2- What are the main markings on the instruments and significance of the markings? 3- What do the different colors represent, if applicable? 4- How can you identify if the instrument becomes inoperative? 5- Can you make adjustments on the instruments, How? 6- What are the common potential errors of the instrument?
I have been able to answer all but the last one on the turn coordinato (little airplane and the ball in the glass tube), but pression sounds like it might be what I'm looking for. I have to turn this in tomorrow. My next challege is figuring out the density altitude, crosswind performance, takeoff/landing charts. lots of numbers for this here math idiot!!!!
Title: Re: ASI
Post by: Fabo on March 25, 2008, 10:03:28 AM
Never quite got density altitude myself... I just play with secondary altimeter normally ::)
Title: Re: ASI
Post by: Rooster Cruiser on March 25, 2008, 11:59:17 AM
Kim, the turn coordinator is electrically driven. There is a little red flag that will pop up in a window when there is no power to the instrument. You can also check for proper operation by turning on the master switch and listen for the sound of the gyro spooling up. No sound indicates the gyro is not turning and the turn coordinator is inoperative.
That should suffice for your ground school.
RC
Title: Re: ASI
Post by: Aviator_14 on June 14, 2008, 11:54:26 PM
You can tell if the ASI isnt working if you climb or descend and the ASI still shows the same speed. When you maintain a constant throttle setting and you climb the plane will slow down. If you descend the plane will speed up. An ASI will usually become inoperative due to a blocked pitot tube or static port.
