The official aviation quiz topic!

Avro · Post by **Avro** » 17 Sep 2005, 14:30

Since nobody found the answer yet, let me show you another picture where you can clearly see the difference in angle of both rails.

http://www.airliners.net/open.file/921551/L/

Why are both rails not inclined with the same angle is my question?

Have fun finding the answer

But it shouldn't be that difficult.

Chris

Avro · Post by **Avro** » 19 Sep 2005, 20:33

Nobody ?

Post by **luchtzak** » 19 Sep 2005, 20:40

The rails are placed so it doesn't create noise when flying high speed?

Avro · Post by **Avro** » 19 Sep 2005, 21:06

It's not about the noise but you are getting close.

keep trying

HorsePower · Post by **HorsePower** » 19 Sep 2005, 22:11

I learnt it long time ago but I forgot it

. Could it be linked with the wing?

Seb.

Avro · Post by **Avro** » 19 Sep 2005, 22:20

nope.

One more hint. The inclination has to do with aerodynamics

If there is no answer tomorrow, I'll give the correct answer myself and ask another question.

Chris

HorsePower · Post by **HorsePower** » 19 Sep 2005, 22:49

The inclination has to do with aerodynamics

Yep, that's why I said it was linked with the wing:

It's like this / before the wing, and like that \ after it. I think the room wich takes the wing is linked with the guter position (in the same direction as the wind).

Sorry for my bad explaination.

Regards

Seb.

Avro · Post by **Avro** » 19 Sep 2005, 23:07

It's not linked with the wing but with the flow over the fuselage. Well ok some part of the flow is linked with the wing but that's not what I want to hear. even if there was no wing the inclination would have been the same.

Think about the air flowing around the fuselage and what people need to optimize when they design non lift generating parts of airplanes !!!

I've helped you a lot now. It should be very easy

Avro · Post by **Avro** » 19 Sep 2005, 23:08

Nonetheless you are getting close as well :p

MD-11 · Post by **MD-11** » 20 Sep 2005, 08:32

To reduce drag and give better aerodynamics.

Avro · Post by **Avro** » 20 Sep 2005, 09:33

Your turn Bart.

The rails are indeed inclined in a way to decrease drag. To be exact they are aligned with the local flow lines along the fuselage. This will enable to have minimum drag. Since the fuselage is a non lift device the optimisation is to reduce drag the most and not to create lift. This is also obtained by avoiding regions with supervelocities. Supersonic speed namely creates a shokwave and therefore a lot of drag.

Chris

MD-11 · Post by **MD-11** » 21 Sep 2005, 11:44

Between which two frequencies are we talking about VHF ( Very High Frequency )?

Avro · Post by **Avro** » 21 Sep 2005, 11:58

VHF is using freq of 30 - 300 MHz which corresponds to wavelengths of 10 - 1 cm

Chris

MD-11 · Post by **MD-11** » 21 Sep 2005, 17:23

Correct

Avro · Post by **Avro** » 22 Sep 2005, 10:38

OK tell me the name of flight instruments which together are called the "basic six". And tell me which of those are working with gyroscopes ?

Chris

Avro · Post by **Avro** » 23 Sep 2005, 22:49

Nobody ?

Avro · Post by **Avro** » 29 Sep 2005, 13:04

Ok since nobody came up with the right answer I'll ask an easier question.

First of all the answer to my previous question:

In the "basic six" we have: Airspeed Indicator; Gyro Horizon; Vertical speed indicator; Altimeter; Direction Indicator and the Turn and Bank Indicator.

The ones working with a Gyro are: Gyro Horizon; Direction indicator (can also work with a magnetic compass); Turn and Bank Indicator. Those three instruments provide the information of the aircraft's attitude.

Now my next question: What does GDOP mean ? and briefly explain the what it is

Chris

Andries · Post by **Andries** » 29 Sep 2005, 13:49

GDOP : Geometric Dilution of Precision

It's a system that determines which is the best sattelite to use from your current possition and what would be a bad selected sattelite to contact.
Is used in GPS.

Greetz,

Andries

Avro · Post by **Avro** » 29 Sep 2005, 18:13

GDOP is correct Andries BUT the definition is not really that ... .

Navigation systems have a certain accuracy which of course isn't 100%. So in fact you don't know the exact location of your plane. You are given a small area and within that area you are situated with your plane. Now when you move (flying) your relative position will change with respect to the beacons on the ground (VOR, DME etc.. or in the space GPS). By changing the "geometry" of the problem the area where you are located varies. Which means that the precision changes as well.

To make a long story short, GDOP tells us that the precision of your navigation device you are using is also dependend on your relative position to the beacons. Whether those are GPS or VOR, DME etc...

Anyway, your turn to ask a question

Chris

Andries · Post by **Andries** » 30 Sep 2005, 19:50

What does the COANDA effect do ?
Also give me the type of Antonov aircraft that uses this effect.

Greetz,

Andries