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Old 30th Dec 2012, 11:40   #221 (permalink)
 
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Its all to do with the output.

I suspect you haven't got the basic concepts abouts whats going on.

All About Circuits : Free Electric Circuits Textbooks

Try reading through that a bit and see if you can work it out yourself.

If you really get stuck just ask.

Power factor is the interesting bit
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Old 3rd Jan 2013, 17:01   #222 (permalink)
 
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Va and Vno-when to use each

Happy New Year to Everyone.

Have been studying the limitations chapter in POF and in particular, the V-n diagram that deals with the load factor limits of the flight envelope, and the various important speeds that you find on that envelope.

Comparing the definitions of both Design maneuvering speed (Va) and Max Structural cruising speed (Vno), I am a bit confused. I would like to know what exactly is Vno useful for? I understand it is the limit above which flight should be attempted in smooth air only (no turbulence?) and then only with caution. Why is it then that everywhere else I read, it says that when encountering turbulence you should slow down below maneuvering speed, in addition to when you are engaging in maneuvers, etc.

I am aware that the definition of Va is often a varied one and commonly misunderstood by many pilots, usually along the lines that you think you are guaranteed in throwing unlimited abuse at an airplane thru abrupt control deflections, etc without having it fail as long as you are below Va, so I am not inviting to dissect this subject unless necessary in answering this post.

So based on the definitions from aviation textbooks of what each speed is, I'd simply like to know which one should be used for what then and why? I too would think Va is the more important one, since it deals with protecting the airframes structural integrity, but then I also been in many an airliner that when it has experienced turbulence, I've never perceived it to slow down a substantial amount as if it was aiming for a speed below Va. So then, in which circumstances does Vno has a practical application?

Thanks

Last edited by Skymaster15L; 3rd Jan 2013 at 17:23.
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Old 13th Jan 2013, 16:32   #223 (permalink)
 
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hi need some help in the following two questions:

Q.1. If you correctly tuned in a VOR situated to your east, your RMI should read ___ and your OBS would read ___

a) 000; 000 with needle central and TO indicated
b) 090; 090 with needle central and FROM indicated
c) 000; 000 with needle central and FROM indicated
d) 090; 090 with needle central and TO indicated

Just cant visualize this one.

Q.2. The accuracy of a DME:

a) is approximately 0.5nm
b) decreases with increase of range
c) increases with increase of altitude
d) is approximately 2 nm

Which accuracy is this? Slant range accuracy increases with increase in range.

Thanks
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Old 13th Jan 2013, 16:46   #224 (permalink)
 
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Quote:
a) 000; 000 with needle central and TO indicated
b) 090; 090 with needle central and FROM indicated
c) 000; 000 with needle central and FROM indicated
d) 090; 090 with needle central and TO indicated

Just cant visualize this one.

Q.2. The accuracy of a DME:

a) is approximately 0.5nm
b) decreases with increase of range
c) increases with increase of altitude
d) is approximately 2 nm
1) you are tracking away from the VOR, therefore have 000 at the top, with the needle centered and the From flag. It would be incorrect if it were tracking 000, with 180 on the VOR and a FROM flag, as you would be going to the VOR and indications would be in reverse sense.

2) the error decreases with range. If you are over the station at 6000' (1nm) the DME will read 1nm, even though you are at the station. At 50 miles, at 6000', the error will be far less.
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Old 13th Jan 2013, 17:00   #225 (permalink)
 
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Quote:
1) you are tracking away from the VOR, therefore have 000 at the top, with the needle centered and the From flag. It would be incorrect if it were tracking 000, with 180 on the VOR and a FROM flag, as you would be going to the VOR and indications would be in reverse sense.
but in this case the VOR will be south of you, whereas the question says its situated to your east.

Quote:
2) the error decreases with range. If you are over the station at 6000' (1nm) the DME will read 1nm, even though you are at the station. At 50 miles, at 6000', the error will be far less.
Yes thats why posted the question. It says accuracy decreases with increase in range.
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Old 13th Jan 2013, 17:06   #226 (permalink)
 
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For Question 1:

Imagine you are VFR for a moment. If you were to see out your window that the VOR is East of your position, then that simply means you are west of it and to (TO) get there you should fly east. Therefore, your RMI will point east as the head of the needle points to the station while the tail gives your position.

A FROM on your OBS, always think of it as your position in relation to the beacon/reference. A TO indication means you should fly East to get to the VOR, FROM means you are LOCATION about of the VOR. If your were to twist the OBS until it shows FROM and then you fly to the VOR your old conventional VOR receiver would be Reverse sensed. HSIs don't sensed revered.

Q2

DME (Distant measuring equipement) not a GPS.... is measured in slant range. The closer you get the larger the error as your aircraft height is more of an issue. So RNT11 dude hit the nail on the head for you answer.

Last edited by BlueSkyLife; 13th Jan 2013 at 17:14.
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Old 13th Jan 2013, 17:51   #227 (permalink)
 
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Quote:
a) 000; 000 with needle central and TO indicated
b) 090; 090 with needle central and FROM indicated
c) 000; 000 with needle central and FROM indicated
d) 090; 090 with needle central and TO indicated

Just cant visualize this one.

Q.2. The accuracy of a DME:

a) is approximately 0.5nm
b) decreases with increase of range
c) increases with increase of altitude
d) is approximately 2 nm
Also interested in these questions.

I'm struggling to understand the first I'm afraid. Surely if the VOR is East of your position you will be on the 270 radial and would need a 090/270 OBS selection to get "to" or "from", respectively. Why would you ever get a reading of 000? Is this talking about a relative bearing?

What does 'correctly tuned' mean. Are you tracking inbound or outbound to the beacon?

Second question, if we know the required accuracy of a DME is 1/4nm + 1.25%, we know A and D are wrong.

C is wrong (accuracy decreases with increase in altitude as the vertical 'slant' component increases), so we are left with B as the least worst option. It's true to say slant accuracy increases with range but then DME is line of sight so eventually accuracy will decrease with an increase in range, as you pass beyond line of sight of the transmitter.

Last edited by taxistaxing; 13th Jan 2013 at 17:51.
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Old 14th Jan 2013, 05:45   #228 (permalink)
 
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Quote:
Surely if the VOR is East of your position you will be on the 270 radial and would need a 090/270 OBS selection to get "to" or "from", respectively. Why would you ever get a reading of 000?
thats precisely why i posted the question

Quote:
It's true to say slant accuracy increases with range but then DME is line of sight so eventually accuracy will decrease with an increase in range, as you pass beyond line of sight of the transmitter.
i was also thinking on these terms but not quite sure if this is really the reason.
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Old 14th Jan 2013, 06:37   #229 (permalink)
 
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Is it possible that the question Q1. is incorrect?
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Old 14th Jan 2013, 06:41   #230 (permalink)
 
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i think it is!

how are your ground classes going
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Old 14th Jan 2013, 09:47   #231 (permalink)
 
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In my opinion the correct answer to the first question would be d). An RMI has no TO/FROM indication, so if the station is to your east, the needle will indicate east. As for the TO/FROM indication, it should indicate TO with 090 selected on the OBS.
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Old 14th Jan 2013, 10:18   #232 (permalink)
 
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thats right, i think the question is wrongly marked

thanks everyone for your feedback

Last edited by Haroon; 14th Jan 2013 at 10:20.
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Old 15th Jan 2013, 04:46   #233 (permalink)
 
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going good by God's grace
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Old 19th Jan 2013, 15:47   #234 (permalink)
 
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Any idea about this one?

What is the PRF given 50 micro second pulse width and a range of 30 nm:

1620 pps
810 pps
3240 pps
3086 pps

What I know is:

Max Theoretical Range = c / 2 x PRF

30 = c/2prf

prf = 2700

Am i missing something, like something to do with 50 micro second pulse width or there is something else to it?

thanks

Last edited by Haroon; 19th Jan 2013 at 15:50.
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Old 19th Jan 2013, 16:21   #235 (permalink)
 
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Long time since I did this but I THINK its 81000/50 = 1620 but can't remember why!
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Old 19th Jan 2013, 16:44   #236 (permalink)
 
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That's a strange one.

Using 162000 nm/sec as SOL I make D the closest. A seems to equal 50 nm not 30.
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Old 19th Jan 2013, 16:46   #237 (permalink)
 
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i think there's a typo in the question. It must be 50 nm
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Old 20th Jan 2013, 04:16   #238 (permalink)
 
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This was great help thanks a lot guys!
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Old 20th Jan 2013, 06:54   #239 (permalink)

 
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There are 96 articles and 18 Annexes, of which only about 6 are questioned on. Facilitation?

You are not expected to know the fine details of contents of the articles, but definitions (sovereignty, etc) would be worth swotting up on.

Also customs requirements and the 5 (out of the 9) freeedoms.

Phil
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Old 20th Jan 2013, 09:35   #240 (permalink)
 
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In real life its Facilitation and Dangerous goods your most likely to come across.
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