Hi All

I need some help with some question i know i got wrong in my Aerody exam!!
Im really struggling with this one and i dont no why. I really thought i had it last time but i guess not missing out by 4 marks scoring a 60% at least im getting better. And this is my last exam and then i can do my flight test.. no pressure and all
But any help will be gr8!! thanks all

1. Reverse Command- what happens to the IAS, ROD when you raise the nose?
2. At Stalling angle(speed) in a climbing turn, an increase in power will? Rate, Radius?
3. A decrease in......, will increase Stalling speed?
4. Forces in a Descent?
5. and can someone help explain the different balance tabs

I can probably help with a couple of those considering it's 4am

2. An increase in power (thus IAS) will decrease rate and increase radius. Rate is highest when speed is lowest. When you add speed, you're covering more ground over the same time so the rate is less. Increasing power will increase radius pretty much because of the same reason, you're covering more ground. I always remembered it like this - slow aircraft = high rate, small radius fast aircraft = low rate, large radius. Remembering this is for the same angle of bank. Have a think about a C152 and a B747 turning at 15 deg AoB, in terms off small/large, what would the rate and radius be?

3. Power?

4. (Glide descent) Lift is less than weight, FcW (Forward component of weight) = drag. What did you specifically want to know?

Hope that helps a little bit,

Cheers

Hi Megzy,

Sorry to hear about your exam. Bummer!

Let's take a look at your questions:

1) Reverse Command: in the area of reverse command, when you raise the nose you need to apply power to stop the airspeed from continually decreasing. In other words, power is not used to increase airspeed at a certain angle of attack but rather to stop the airspeed from continually falling away at a given angle of attack. So, if you raise the nose in the area or reverse command you'll get decreasing airspeed and if you were in a descent, you would get an increase in your rate of descent.

2) We are assuming the angle of bank is unchanged in this question. Ellzy covered this one but make sure you realise the rate Ellzy mentions is the rate of turn not the rate of climb. Obviously if you add power in a climb (or climbing turn) you are going to have an increased rate of climb because of the increased amount of excess power available. You are at the critical angle of attack (as specified in the question) so adding power will give more thrust and you can't increase the angle of attack any further without stalling. The extra thrust translates to extra speed. Increased speed in the turn means a lower rate of turn and a larger radius.

So, the answer would be: increased rate of climb, decreased rate of turn, increased radius of turn.

3) A decrease in power and a decrease in flaps will increase the stall speed. A good tactic is to look at the factors affecting the stalling speed and include or eliminate them one by one when answering these types of increasing/decreasing questions. The stalling speed and factors affecting it are described on page 10.3 of the textbook. These factors are weight, load factor, power, flaps, ice/damage and C of G position.

4) Forces in a descent are described on page 8.5 but basically, as Ellzy said, in an aircraft in a steady descent, lift is less than weight (since the drag is actually helping to support some of the weight) and thrust is less than drag (since the weight vector has a forward component which acts in the same direction as thrust). That last one can be tricky to visualise so take a look at the diagram on 8.5 to get a clearer idea.

5) Balance tabs are described in section 12.1 in the textbok. If you have any specific questions relating to control, post them and we'll attack 'em for you.

Cheers,

Rich

P.S. thanks for helping out, Ellzy

No worries, thank YOU for answering and expanding.

I didn't think of flap for #3, but it makes sense.

OMG you guys are LEGENDS...

Thanks so much for those and information that makes sense

There will be many more..

With the balance tabs...

I got a question about what type of tab reduces Induced Drag??
I was totally unsure about this

HI All,

Si im back to square one with Aerody!! I cant get it and frustrating me like all crazy.

I have to wait ill January due to being full booked out and my instructor rekons i should stretch the study out a lil more with this one and go from the beginning.

I need some serious help with the design features, my last exam it was the dominant thing and well didnt end well...
i cant find any bob tait questions on it so i think practice questions on them would help.

Can anyone think of some?? or found them somewhere

THanks a million

Gidday Megzy.

Can you let me know what design features had you stumped?

In the Aerodynamics book you will find some discussed under wing plan form and washout on Page 5.4 lift augmentation devices - Page 7.7. Some pictures on Page 7.13. Also in stability as longitudinal and lateral dihedral. The various types of trim tabs, ailerons and spoilers on Page 12.1 to Page 12.6.

Any feedback you can give me would be greatly appreciated.

Bob

Well all of it really....

I had questions talking about servo tabs, spring tabs, balance tabs(which i know)
but i cant remember exactly the questions.

But alot of the phrasing in the book is different to the ones i get in the exam.
Aerodynamic balance tabs...

So i have my Aerody again tomorrow...
really hoping to make it my last.

Any last words from the experts?!

Feeling confident, study full on and from a different book this time which has helped my understanding a little better too.