Jeppesen Chapter 3
 

I am currently in the third chapter of the Jeppesen private pilot maual and was wondering how in depth you have to really know Section B Stability?

I got the three basic airplane axis of an aircraft but how through does one need to know power effects, keel effect, and directional stability? This stuff is boring me to death.:mad:

Need to move on to the important topic, stalls.

Yes, I know exactly what you mean. It sounds kind of boring but it is aerodynamics and is too important to skip over. Read about keel effect, stability, and how aircraft are designed to be more stable in one area at the sacrifice of another. Yes, it is very general info and you might forget all about it when you get to chapter 9. What I do is I google these and find out how keel effect relate to ships. When boring google it and you might be surprised of how interesting it may seem. The Jepp is a great book BTW, I absolutely loved it.

Alright, lets talk about stalls.

How about an elevator trim stall. Airplane pitches up until the critical AOA is reached and stalls. When it stalls, the nose drops, AOA is reduced, airspeed is gained. But, if the trim is left where it is, it will eventually pitch up to the critical AOA again, stall, gain airspeed and go on continuously like this.

So what kind of static and dynamic stability would this be an example of?
Also, are we talking lateral, longitudinal, or vertical stability?

How about a cross controlled stall. How would we define the stability in the yaw axis after the stall occurs?

What theories of aircraft design promote stability so that we can perform stalls safely? Wing dihedral, ventral strakes, etc?

Everything in aviation is related.

OK thanks guys. Do you want to hear what confused me for a bit?


We have the three axis: Longitudinal, Lateral, and Vertical. Right? Yet the longitudinal stability of aircraft relates to it's lateral axis.:confused:

long... stability is stability OF the longitudinal axis, or stability about the lateral axis and vice versa

so, if you were imagining lateral stability, imagine the lateral axis. Then imagine that axis moving. If you then throw in the longitudinal axis into your imagination, the lateral axis will be moving about the longitudinal.

Hows that??

We have the three axis: Longitudinal, Lateral, and Vertical. Right? Yet the longitudinal stability of aircraft relates to it's lateral axis.:confused:[/QUOTE]

I burst out laughing because that's exactly how I was after reading that sentence!! But yes 250 made it clear as mud. It also helps to read more than 1 text. I read Machado because he uses a lot of humor while the Jepp is very thorough and to the point. Both has its advantages...

I would think that any pilot or pilot in training, would want to know the practical application of any element of flight physics as it directly pertains to aircraft handling and/or performance. Just like when you were first introduced to algebra in Jr. High, you most likely saw little to know practical application to anything else. However, you later found out that there was no way on earth you would ever understand three dimensional mathematics (calculus) without understanding the practical tool like nature of fundamental algebra. Thus, the two were connected.

Want to get on with stalls? Well, which of the three primary axes is initially involved in the stall? Need to recover from a stall before it develops into a full blown spin? Well, which of the three primary axes will you pivot the nose and tail around in order to decrease the AoA and increase airspeed necessary to reverse the stall and prevent a possible spin? Did you fail to prevent the stall that lead to the spin? Then which of the three primary axes will you need to halt the rotation on the most before recovery from the spin is possible? Ooops - did you accidentally load the aircraft and pushed the CG too far forward or too far aft? Then which of the three primary axes will be affected and "why" could that be important to you during the take-off roll, for example? And on, and on, and on....

Have fun with the fundamentals! They are the building blocks of skill. Train to be more than just a pilot - train to be a real Aviator. That's what I plan to do, anyway. :)

Agreed, 1,000%

I suggest reading the book: "The Complete Guide to Flight Instruction" - Gregory M. Penglis, 1994. I also strongly suggest: "The Proficient Pilot Volume I" - Barry Schiff. Of course, the book: "Stick and Rudder" simply cannot be overlooked by any pilot in training.

Every student pilot should have at the very least, these three books in their aviation library.

You do have an aviation library, don't you! ;)

[if not, start building one!]