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Author Topic: Is the bernoulli concept...  (Read 5255 times)

Offline Naufal the B. S.

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Is the bernoulli concept...
« on: 25/07/2009 02:20:28 »
I think, it's influencing a little bit of a very very big and heavy airplane lift.
I think, the lift of the airplane influenced by sloping aileron.


 

lyner

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Is the bernoulli concept...
« Reply #1 on: 25/07/2009 09:37:02 »
The aerofoil shape can't be the only way to obtain lift or no planes could fly upside down. It's just a good way to obtain lift with low drag.
 

Offline LeeE

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Is the bernoulli concept...
« Reply #2 on: 25/07/2009 15:39:42 »
Aerofoils are not necessary to get lift - a flat surface with sufficient Angle of Attack (AoA) will work...



Aerofoils are much more efficient but most aircraft that are expected to perform aerobatics will have a symmetrical aerofoil i.e. the curvature will be the same above and below the aerofoil centerline and lift is then produced by having a positive AoA, which can be achieved regardless of whether or not the aircraft is upside down by simply pointing the nose up (absolute up, that is, not relative to the aircraft).



With typical light aircraft, airliners or cargo planes, which are not expected to perform aerobatics, you can use an asymmetric aerofoil, which is more efficient.  Even with an asymmetric aerofoil though, it's still possible to fly upside down, although in practice the elevator may not have enough authority to maintain the required AoA while inverted.
 

Offline Naufal the B. S.

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« Reply #3 on: 26/07/2009 00:40:32 »
But, i think, a very very very little ammount power to lift the airplane. And the conclusion, without aerofoil, the plane will fly.
 

lyner

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Is the bernoulli concept...
« Reply #4 on: 26/07/2009 11:49:46 »
But, i think, a very very very little ammount power to lift the airplane. And the conclusion, without aerofoil, the plane will fly.
Of course it will fly - but less efficiently. The "very little power" still counts when you're flying a long way and on expensive fuel.
 

Offline Naufal the B. S.

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Are you a scientist?
« Reply #5 on: 27/07/2009 07:36:34 »
I have a book, it has chapter that tell about uncorrectly aerofoil. The writer (physician) told to aeronautics expert that aerofoil just give little ammount of lift. And the ae answered with confusing answers!
What's your opinion?
If so... Must i give aerofoil shape to my glider?
 

Offline Naufal the B. S.

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Are you a scientist?
« Reply #6 on: 27/07/2009 07:42:45 »
Why it gets a big five invention theory?
Whereas, it isn't important. Example, the kitty plane can flies without aerofoil.
 

lyner

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Is the bernoulli concept...
« Reply #7 on: 27/07/2009 11:40:29 »
1. The aerofoil produces lift with low drag. That is worth a lot of money.
2. It is not essential for an aircraft to obtain lift.
3. Economics are very important so, where they can, they use aerofoils.

IS there any more to be said without going into the details?
 

Offline Madidus_Scientia

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Is the bernoulli concept...
« Reply #8 on: 27/07/2009 14:26:32 »
2. It is not essential for an aircraft to obtain lift.

Did you mean it is essential?
 

Offline LeeE

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Is the bernoulli concept...
« Reply #9 on: 27/07/2009 14:54:10 »
When you say 'kitty plane' do you mean the Wright Brothers' aircraft?  This aircraft did have aerofoil wings.

Have a read of:

http://en.wikipedia.org/wiki/Aerofoil

(Actually, that article states that lift is generated perpendicular to the direction of movement but one of the things the Wright Brothers discovered in their tests with gliders was that with an aerofoil the lift is actually angled slightly forward, towards the direction of flight, and not just directly upwards.  It was this factor that actually made the Wright Flyer 1 feasible because they would have otherwise needed more power than they could have produced within their weight limits using the engine technology of the time.  Even then though, they had to design and make their own engine to ensure it was light enough)
 

Offline Naufal the B. S.

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« Reply #10 on: 28/07/2009 07:37:07 »
So... Still i must install aerofoil fins to my glider?
I installed aerofoil fins to my glider. And the results, my glider success, spinning spinning spinning... upward 360o!
 

Offline Naufal the B. S.

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Teleportation and Time machine
« Reply #11 on: 28/07/2009 07:41:18 »
But, i think, aerofoil still help the aircraft to ease lifting.
I've just found the function of aerofoil. Sorry for our debate.
 

lyner

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Is the bernoulli concept...
« Reply #12 on: 30/07/2009 00:22:41 »
2. It is not essential for an aircraft to obtain lift.

Did you mean it is essential?
Bad structure: I meant an aerofoil is not essential for lift.
 

Offline Naufal the B. S.

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« Reply #13 on: 30/07/2009 06:11:23 »
Still i must install aerofoil fins to my glider?
 

Offline Madidus_Scientia

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Is the bernoulli concept...
« Reply #14 on: 30/07/2009 10:43:22 »
Oh I get ya now
 

lyner

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Is the bernoulli concept...
« Reply #15 on: 30/07/2009 12:29:12 »
Still i must install aerofoil fins to my glider?
The wings should be aerofoil - particularly for a glider, I think. You should use an established design if you want it to perform well. Aerodynamics is not easy to predict by the 'look of things'. (Quote from Colin Chapman - sports car designer)
 

Offline Naufal the B. S.

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Is the bernoulli concept...
« Reply #16 on: 30/07/2009 12:50:36 »
once again about bernoulli...

bernoulli tolds, if the nozzle of pipe more tight, tthe pressure will less. How about the rocket nozzle? Why it should have tight nozzle?

Sorry for my bad english.
 

lyner

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Is the bernoulli concept...
« Reply #17 on: 30/07/2009 15:13:38 »
Bernoilli says:
Narrow nozzle = high velocity (also low pressure but that's the pressure IN the nozzle, not when it comes out)
That's what you want, isn't it. for a rocket? i.e. high velocity of propellant ejected.
 

Offline Naufal the B. S.

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Still i must install oxidizer to my aerosol rocket?
« Reply #18 on: 31/07/2009 00:13:19 »
Ah yes...
So... Which is the biggest pressure that can make? The narrow nozzle? Or big nozzle?
 

lyner

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Is the bernoulli concept...
« Reply #19 on: 31/07/2009 12:04:40 »
It all depends upon the supply resistance and original pressure. If there is a long thin hose, the pressure will drop a long way if you open the end right up. If you have a very low resistance supply (large bore tube), the pressure is not affected as much by the width of the nozzel.
You either do the sums or do the experiment.
The biggest pressure is when there is no flow - but that's no use to anyone.
 

Offline Naufal the B. S.

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Still i must install oxidizer to my aerosol rocket?t
« Reply #20 on: 01/08/2009 02:05:51 »
Ouw, ya!
Thank you, sophiecentaur sensei!
I'll close this thread
 

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Still i must install oxidizer to my aerosol rocket?t
« Reply #20 on: 01/08/2009 02:05:51 »

 

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