Learning about lift generation - a waste of time.

[spacesailor]

I'm with OME !.

I have been having a go at the " online tutorial test "

   

some of the Maths  ( diagrams of angles ), I have NO idea what OR how to answer that question, AND I cannot find Keys on this desktop PC to type some of those  Hieroglyphics.

angles vector  cosine  AND Blooodi french are All foreign to me.

spacesailor

 

[spacesailor]

IS " centripetal force, similar OR the same as Centrifugal force. ?.

In the above diagram.

Just one of hundreds I have to close my eyes to. 

OR go crazy.

LongVerticalChuck

LongHungChuck

Long=Wide/Costume

spacesailor 

Edited January 5, 2021 by spacesailor
added more

[Garfly]

Why are you putting yourself through all that stuff, Spacey?

I think most of us are 'with OME' on this point.

I reckon you're better off trying to contact our magnificent ancestors.

They still have a message for us (till drone-tech makes wing-flying passé) :

 

 

 

Or (if you're not into spirits) taking a another look at this old favourite (very practical):

 

 

Edited January 5, 2021 by Garfly

[aro]

1 hour ago, old man emu said:

Why is it critical to the practical application of piloting skills that the pilot knows that 

 

 

 

It is important to understand the effect of air density on lift. It is a critical part of performance calculations.

 

It is also important to understand the effect of velocity - that lift available is proportional to the square of the velocity.

 

Other than that you have wing area (a bigger wing can lift more - not complicated) and the coefficient of lift. The coefficient of lift is just a constant that allows you to tie all the other numbers together allowing for different characteristics of different wings.

 

As for the spirit level:

 

Imagine you are in an aircraft climbing at a 5 degree angle at 60 knots. Now you close the throttle and glide, and the aircraft descends at a 5 degree angle at 60 knots.

 

The angle of attack remains the same if the airspeed and weight are the same. There is virtually no change in the angle of attack from the climb to the descent, but the angle of the fuselage has changed by 10 degrees. The reading on the spirit level will change by 10 degrees - more than half the typical stall AOA - but the real angle of attack has not changed.

 

If it was possible to read angle of attack with a spirit level you can be sure it would have been done long ago - but it is not.

[old man emu]

42 minutes ago, spacesailor said:

IS " centripetal force, similar OR the same as Centrifugal force.

Spacey, the answer is NO, not because they are different forces, but because Centrifugal Force is what is called a "fictitious force" - any force invoked by an observer to maintain the validity of Isaac Newton’s second law of motion in a reference frame that is rotating or otherwise accelerating at a constant rate.

 

Take the situation where you have a weight on a string and you start whirling it around over your head. You feel a force in your hand. That's your feeling of the force you are exerting on the weight to keep it moving in a circular path. You are pulling the weight towards you. That force is called CENTRIPETAL FORCE,  which means "center seeking" force.

 

This quick video explains what is going on 

 

 

 

[Garfly]

 

Am I missing something here? Spacey and OME seem to be complaining loudly about there being too much 'scientism' in pilot education and yet they seem to be the ones that just can't get enough of it?  Go figure!  Human factors! LOL

[old man emu]

There's a time and a place for everything. Sitting in the left hand seat commiting aviation is not the time to be doing calculations involving multiple variables. However, logged into a forum, with access to reference material and calculators is the time to ponder the intricacies of the physics.

[aro]

7 minutes ago, old man emu said:

Sitting in the left hand seat commiting aviation is not the time to be doing calculations involving multiple variables.

Performance calculations are often done before takeoff, but it may also be necessary to do them in flight.

 

You don't use the lift equation in the air, but you learn it on the ground so that hopefully in the air you understand the effect of air density, the limitations when you are doing 120 knots in an aircraft with 50 kt stall speed etc.

[facthunter]

  Most of the formulea are used at the preliminary design stage. At the stall point the lift/drag ratio has gone to a bad place. Your wing has become very inefficient at providing lift. and you have more drag than a short time before. If the plane is not flying with the rudder keeping it in balance onw wing will drop before the other, When that happens the upper wing becomes unloaded and the falling one becomes more deeply stalled. IF you try to pick it up with aileron it gets worse and if you try to keep the nose up  by more back stick, you are set up to spin . Nev

[Kyle Communications]

This is easily answered...for god sake someone take a spirit level with then when they fly next and orientate it down the centreline of the aircraft and tell us what you see

 

[spacesailor]

AND I had thought, that the designer has done all those density and all the rest of the other sciance maths during the design stage !, and I only have to say "it,s a nice day to fly " not to cold ( icing   ) not to hot  (themals ),  plus engine seizure / fuel evaporation.

So

Designed for My day

spacesailor

[old man emu]

2 hours ago, Kyle Communications said:

This is easily answered...for god sake someone take a spirit level with then when they fly next and orientate it down the centreline of the aircraft and tell us what you see

Took the letters right off my keyboard.

[spacesailor]

CAN I GET PERMISSION TO USE MY PLANE ?.

And I shouted it out loud !.

spacesailor

[old man emu]

2 minutes ago, spacesailor said:

CAN I GET PERMISSION TO USE MY PLANE ?.

And I shouted it out loud !.

spacesailor

No! It hasn't got one of them bubble things.

[spacesailor]

IT WILL HAVE.

A spirit level,  And a Bubble, that fell off a survayers theodalite. 

Anything else needed? .

spacesailor

[jackc]

Who cares!  Just go fly the plane and enjoy it......the Wright Bro’s did 🙂

[old man emu]

The Wright Bros were probably the most experimental aerodynamicists of the few years both sides of 1903. 

[spacesailor]

BUT

That But is always lurking !.

Untried aircraft with low, LOWER, hour pilot.

Any problems will I get it right immediately , or do the wrong manoeuvre with dire consequences.

it happens when lease expected !.

spacesailor

[F10]

No way....all these scientists lied to us...I have found the mother load....the real reason for lift beneath your wings!!

[spacesailor]

Thats dead on the nail !?

SO TRUE

spacesailor

[facthunter]

You don't need to know what's causing lift to fly properly. Know what affects it (Density altitude, airspeed and angle of attack. YOU control the angle of attack with the elevators and it relates to the RELATIVE airflow. Not the horizon.. Tilt the nose down at the right rate and you will reach a point of no lift from the wing and you will float on the seat and be "weightless" At the other end of the scale put the wing at an AoA above about 14 degrees to the relative airflow and the separation of flow will cause a large loss of lift and big increase in drag. Those are the 2 limits of the wing  to support you in flight and in the normal sense. (Aircraft right side up not climbing or descending vertically etc).  Not so difficult to understand.  YOU control the AoA with the elevators.  IF it stalls it will be because of  "something" you did...Nev

[Yenn]

Spacet mentioned not too cold, iceing, not too hot, thermals.

I have never experienced carbie iceing on a cold day up here in Qld. I did once have an aborted takeoff due to it in Victoria.

Those hot humid days of summer are the worst time for carbie ice.

Even airframe ice is not a problem at really cold temps.

[facthunter]

Every now and again there's a carb icing event that gets reported and there must be many  where it happened with no trace of a fault when the engine was examined. Some engines are far more prone to it, like when the inlet manifold is very long.( VW and Chev Corvair)  The Lycoming  inlet tract goes through the bottom of the sump and is always heated by the engine oil, cooling the oil and heating the inlet air. Nev

[spacesailor]

The half VW, use an oil line wrapped around the inlet pipe & it seems to work.

BUT

I haven,t flown my Hummel yet, without that oil wrap around, so no worries over my plane ,s icing. LoL

spacesailor

[Yenn]

Does a heated inlet tract stop carbie iceing?

My experience tells me that the iceing occurs at the venturi which is upstream of the inlet tract and that heating the tract would have very little affect on the temperature and humidity at the venturi.