Yet Another Trivia Quiz

[flightnse]

i would say about 270

[HardCorePawn]

QUOTE (flightnse @ Jun 30 2008, 11:32 AM) <{POST_SNAPBACK}>

i would say about 270

???

Anyway, the theory is this:



The AoA of the airfoil (or wing) needs to change as airspeed changes to maintain level flight... as speed is reduced, we increase the AoA to compensate (airflow over the wing decreasing = decreased lift, increasing AoA = increases lift and vice versa)... now if we expand the diagram to include the entire aircraft:



It stands to reason that if the AoA of the wing is changing, the AoA of the rest of the aircraft (including the prop) must also change... as everything is fixed... so the AoA of the prop must be changing.

I wonder if the same applies to the trike in FSX, as the wing is actually hinged, so you can alter the AoA of the wing independently from the rest of the trike?


Figured I would go with the logic argument, as I cannot be bothered trying to draw vectors

EDIT: Man, went and did some reading on this... and trying to understand the theory is making my head hurt (I got up early to watch the football this morning, so I'm not very with it at the moment!)

But it is all to do with Rotational Velocity and Forward Velocity determining the relative airflow and hence AoA of the prop...

If you change either the Rotational Velocity (increasing or decreasing RPM), or the Forward Velocity (speed brakes? or dropping flaps maybe) the relative airflow (and hence AoA) changes... as the triangle shape is changing...




Thx for forcing me to look this up... CPL Principles of Flight is coming up soon...

[flightnse]

what do you mean ???

[HardCorePawn]

QUOTE (flightnse @ Jun 30 2008, 01:45 PM) <{POST_SNAPBACK}>

what do you mean ???

Mate... probably a bit of overkill quoting my entire post... just to say WTH?

That is a somewhat complicated explanation as to how/why the Angle of Attack (or AoA), of a fixed pitch prop, varies with changes in airspeed and/or rotational velocity of the prop. What happens is that the relative airflow across the blade changes, but the chord line of the prop blade remains constant. As with a wing, the AoA is the angle between the chord line and the relative airflow.

So if the relative airflow is changing, the AoA must change as well.

[Charl]

The way it was explained to me was using the 10-speed bike analogy.
A fixed-pitch prop is stuck in 5th gear.
Variable-pitch allows you 1st (Fine) to 10th (Coarse).
I think the AOA terminolgy is a little misleading, but it refers to how "bluntly" the aerofoil cuts through the air.
A fixed prop is trying to haul too much air at rest, and not enough at speed.
So at rest, high AOA, at max speed, low AOA.
V-P has the same AOA at all speeds, in theory, which is why they take the trouble to make 'em.

Now if you two have finished with the physics lecture, HCP has a turn now.
Minus five marks if you need an aeronautical degree to answer the question...

[HardCorePawn]

I would post something... but stupid internet seems to be limited to NZ at the moment... all international sites are down... so unless you want a nzff.org trivia question, you'll have to wait a little while

or I can dig something out of my Air Law study guide

[Timmo]

Yep your turn HCP- Nice one.

Gold Star for Charl for 'splainin it nicely too.

[HardCorePawn]

I actually just realised that according to the original rules, you're not supposed to participate for 3 goes after you've got one right... so I will ask
my question and then lurk for a while...

Q1: What Transponder code should you use when operating in the area of airspace designated G276 between ECT & MCT?
Q2: What code should you use between MCT & ECT?

[Timmo]

QUOTE (HardCorePawn @ Jul 2 2008, 09:50 AM) <{POST_SNAPBACK}>

I actually just realised that according to the original rules, you're not supposed to participate for 3 goes after you've got one right... so I will ask
my question and then lurk for a while...

Oh yeah.....doh... Guess I'm out for a while too then

[travnz]

HCP IFR or VFR?

[HardCorePawn]

good call... VFR... and bonus points if you give your reasoning!

[travnz]

HCP are you sure you have the Correct GAA number for this question??
Just double check for me.
Anyway Q2 is 1400.

[HardCorePawn]

It really makes no difference... G276, G275... the important fact is that it is GAA...

[travnz]

Well no code is needed.

[HardCorePawn]

It is a bit of a trick question... as the GAA's cease to exist at night ie. after Evening Civil Twilight (ECT) and before Morning Civil Twilight (MCT) and they revert to Class G airspace...

So, you are correct, no code is 'needed'... but you *should* squawk 1200...

1. Because you want to be seen by secondary radar
2. Because you want to be seen by TCAS/ACAS

it is dark after all!

And yes, in a GAA during daylight, you should squawk 1400...

So you get both halves of the choccy fish

[Charl]

QUOTE (HardCorePawn @ Jul 2 2008, 09:50 AM) <{POST_SNAPBACK}>

I actually just realised that according to the original rules, you're not supposed to participate for 3 goes after you've got one right...

Now while Travnz figures out another diabolical question...
how about doing a little penance, and explaining all that jargon?

[Ian Warren]

I was hoping HCP was asking - what wingtip fuel tank did this resemble .. and get the choky fish .. food for thought

[A185F]

I REALLY want that choc fish, it just looks sooo inviting !!!!!!

[HardCorePawn]

What jargon?? (i'm hoping you're not referring to all the physics related stuff... coz i barely understand it myself! )

MCT = Morning Civil Twilight = when the sun comes up and it is officially daytime (specifically it occurs when the centre of the sun's disc is 6 degrees below the horizon)

ECT = Evening Civil Twilight = when the sun goes down and it is officially nighttime (specifically when the centre of the sun's disc is 6 degrees below the horizon

GAA = General Aviation Area = A piece of airspace reserved for VFR training and gliders. Active during daylight hours only, and are released as class G airspace. You are also free of the magnetic/altitude table... ie. VFR cruising levels (north odd + 500, south even + 500) do not apply.

Squawk XXXX = Set your transponder to code XXX and put it in Mode C (ie. ALT mode). Mode C means the transponder will transmit altitude information.

TCAS = Traffic Collision Avoidance System
ACAS = Airbourne Collision Avoidance System

Both of these are systems used to identify nearby air traffic and give you visual and audio alerts for conflicting traffic. They work by using transponder transmissions to identify the location and altitude of nearby aircraft.

Secondary Radar = Radar system that relies on Transponders transmissions to locate and highlight aircraft on the radar display. It does not use reflected microwave signals (like Primary Radar), so if you do not have a transponder, or it is not switched on (either Mode A/ON or Mode C/ALT), you are effectively invisible to secondary radar. Most of NZ is only covered by Secondary Radar, so having your Transponder on = a 'Good Thing'™

Choccy Fish = Chocolate Fish = Delicious confectionery consisting of marshmallow covered in chocolate, in the generic shape of a fish. Commonly awarded as a prize for correct answers in quizzes.

[Charl]

QUOTE (Charl @ Jun 30 2008, 06:52 PM) <{POST_SNAPBACK}>

Now if you two have finished with the physics lecture, HCP has a turn now.
Minus five marks if you need an aeronautical degree to answer the question...

HCP take MINUS FIVE MARKS...
And add 'em back for the last line, for showing you do have a sensayumour.