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Arrangment of forces
04-14-2010, 12:33 PM
Post: #1
hye. i'm still new in aviation industry.i mean i want to know more about aviation,

can tell me more about arrangement of four force while level flight,climbing, and descending?i would appreciate it..:]..what is equal,what is less than bla,bla....
04-14-2010, 12:51 PM
Post: #2
Straight and level - Lift equal to weight and thrust equal to drag.
Climbing-Lift is greater than weight,drag greater than thrust.
Descending-Lift is lower than weight,thrust greater than drag.

Correct me if im wrong.


VH-CZW is ready runway 29,for upwind departure received Alpha!
04-14-2010, 01:24 PM
Post: #3
Thank you zeff for your information..:]..<br /><br />-- Wed Apr 14, 2010 1:25 pm --<br /><br />one more,,can explain to me what is wash in and wash out? if nice,,put some diagram?
04-14-2010, 08:13 PM
Post: #4
Dear e747...
first you need to understand what is an angle of incidence..
see here:
(please see the explanation with the aircraft diagram)

Wash out: A decrease in angle of incidence from root to tip of the wing

Wash in: An increase in angle of incidence from root to tip of the wing

I hope now you have clearer view or at least you can imagine...what exactly this wash2 thingy... Smile
04-17-2010, 03:12 PM
Post: #5
What is dynamic stability?What i understand about it is the aircraft will roll back to its original position if the aircraft rolling it?and if the aircraft try to yawing from its original position either left or right,it will try to push back the aircraft to its original position.

one more thing, what is the function of trim tab ground at the empennage section and function of horn balance..
04-17-2010, 05:42 PM
Post: #6
Dynamic Stability...
see here: <!-- m --><a class="postlink" href=""> ... ontrol.pdf</a><!-- m -->

About the horn balance
its function is to reduce the control loads /stick force produced by the hinge moment...How? by reducing the hinge moment
sorry no diagram...

As for trim tab ground...
Sorry..I have no idea...can you show us the photo/diagram/sketch ?

Correct me If Im wrong... Cool
04-17-2010, 10:46 PM
Post: #7
i mean this,

<!-- m --><a class="postlink" href=""> ... img_35.jpg</a><!-- m -->
04-19-2010, 09:11 PM
Post: #8
this is my explanation:

the basic four forces are: lift and weight, thrust and drag.

During acceleration, thrust is greater than drag. it means that we feel the inertia - our body try to remain at rest but somehow it is pressed back to the seat that we seat in. (consider the passenger seat that installed facing forward.)

During deceleration: reverse the above condition.

Constant Speed, Level flight: The lift and weight is equal. Same with thrust and drag. so we feel no force acting on our body.

During climbing or descent: if it is done in constant speed, you will also feel no force acting on you. Be careful, the lift and weight are equal during climbing. the lift exceeds the weight during the moment of a/c rotation, either nose up or down. after that everything is equal provided there are no turbulence etc.

usually when travelling in a n airliner, in a fair weather condition- usually you would feel the acceleration during take off roll and a moment when the pilot is doing rotation (to bring the tail down so that wing will increase it's angle of accident). you'll feel the 'floating' moment just about few second where the lift is so great. after the lift and weight, drag and thrust have settled down, you feel no more force pushing your body. the only thing you will notice is the a/c is climbing - due to the tilted horizon.

The other event is during descent and approaching runway. you might come across where the pilot extend spoilers to reduce lift and speed and you can feel the deceleration . during approaching, landing gears are down, flaps are down - the drag is greater where the a/c is decelerate much more that you can feel the inertia.

e747, the image you got is a fixed trim tab. it means that pilot cannot adjust it during flight. the only way to adjust it is during a/c is at ground. the pilot will tell maintenance personnel how much the drift during flying and the engineer will bend the fixed trim tab either side enough according to his experience and knowledge - this is much more to trial and error method.

“A friend cannot be considered a friend until he is tested in three occasions: in time of need, behind your back, and after your death.”
04-20-2010, 12:29 AM
Post: #9
thanks for very quite detail explanation masomo and also about the fixed trim tab...
I had no idea what exactly that thing in that photo...until you explained everything...huhu
and yes I agree with you it can only be adjusted on the ground...the engineer told me about this...
04-21-2010, 09:39 PM
Post: #10
thank for the information..its look complicated to me..btw,mr.aviator and mosomo,thanx for the information.. btw, my lecturer told me about trim tab ground, it only have in small aircraft like a cessna. it never have on commercial it? my lecturer from INDIA,, ex INDIA Engineer..

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