Advanced Higher Physics Investigation Help

OP

Electromagnetism is just ********ed up!!! Well, it's not my cup of tea :wink:

I'm in Physics tomorrow so I'll see how my ideas fair against my teacher's "constructive criticism" and should be able to decide how I want to approach my investigation. I've already thought up ingenious ways of measuring lift. :smile:

Reply 3

griffinsnight

HI, I'm doing my investigation at the moment and I am also interested in aerofoil topics as I am considering an aviation based course at University.

I find it very disconserting that you are abandoning you airfoil idea so quickly - I can see no reason why it sholdn't work - that's what I'm doing!

My investigation will use a wind tunnel that the department has (minus a fan which I have to set up) and the use of an airfoil which I have to build (or get the Technical Technicians to make for me!)

Just give it a bit more reasearch on the web - I've found plenty of useful sights - the Physics behind it is easy to find and NASA had a very good site about Wind Tunnels.

I'm doing how angle of Attack of the airfoil affects the whole Airfoil lift - I've found out you get 2 ways of measuring lift - place the airfoil attached to a sting with a weight which you measure the change in weight and then you load it on the wall for the second lift measurement and use a load cell - apparently that's difficult but I'm stubborn!

Email me if you wanna ask anything about what I'm doing - if anyone wants to give me any advice about it - feel free! :smile:

griffinsnight xxx

Reply 4

I think this would be a pretty good topic to explore.

I don't know if you've heard of NACA aerofoils, but NACA was like the predecessor to NASA, and they compiled a large list of aerofoil designs, describing them in only 4 digits.

For example, a NACA 6716 aerofoil. The first digit, 6, represents the maximum camber. The 7 represents that fact that the maximum camber occurs at 70% of the cordline, the 16 represents the fact that the maximum thickness of the aerofoil was 16% of the chord.

From these 3 facts there are a list of formulas which can help you deduce the surface geometry, and hence the performance of the aerofoil - including it's lift co-efficient at varying angles of attack and the pressure distribution across the surface at varying velocities/viscosities/etc etc.

So if you could find a copy of a list of NACA aerofoils then it's pretty safe to say you have a large volume of research material at your disposal.

Of course, as an Engineer, I would probably use MatLab or Maple and write programs to evaluate the properties of an Aerofoil based on it's NACA code, but there will be other ways to go about it if you aren't well rehearsed in MatLab or so(although you will be once you start your degree :wink:

)

Reply 5

Dave13

8

I'm meant to be investigating the 1/r^2 relationship in equations such as the one for the force between two masses and the force between two charges whatever that's supposed to mean. To be honest I chose it because I got told by my teacher that it was supposed to be a good little investigation to do but it immensely boring and the results from the experiments I got were really less than impressive (I was meant to use one of the sets of data to calculate the gravitational constant and I am about 200% out :s-smilie:

).

Anyone care to share their opinions about whether it would be too late to change and still do another one properly at this point?

Reply 6

OP

Dav_13

Anyone care to share their opinions about whether it would be too late to change and still do another one properly at this point?

Well we haven't even started investigating properly yet and, to be honest, I haven't definitively decided on my topic either. :frown:

I'd say find something you're more interested in and start again. It's no use going with something your teacher said would be a good one simply because they said it was a good one. I'd rather be 100% committed to seeing the investigation through because I enjoy the topic rather than because my teacher told me the examiners liked it.

Reply 7

Dave13

8

Cheers, seems like a fair shout. I'll be in for a fun day next time I have physics when I tell my teacher that I plan on starting again :wink:

Reply 8

OP

Thought I'd post this to update this thread in the hope I can get some more assistance :wink:

I'm actually completely stumped on what experiments I can do to investigate my chosen topic (I've not even decided on the title of my investigation yet!! :confused:

) - airflow over certain aerofoils. I've thought of using different aerofoils and somehow investigating the co-efficient of lift for each one. :s-smilie:

Again, any and all help will be much appreciated!! :biggrin:

Reply 9

Stevo the Victorious

Thought I'd post this to update this thread in the hope I can get some more assistance :wink:

I'm actually completely stumped on what experiments I can do to investigate my chosen topic (I've not even decided on the title of my investigation yet!! :confused:

) - airflow over certain aerofoils. I've thought of using different aerofoils and somehow investigating the co-efficient of lift for each one. :s-smilie:

Again, any and all help will be much appreciated!! :biggrin:

L = \frac{1}{2} \rho V^{2}C_{L}c

This the the basic formula for the lifting force of a wing. V is the airflow velocity, L is the lifting force, c is the chord length(distance from leading edge to trailing edge), CL is the lift co-efficient, rho is fluid density. You could investigate the changing of the lifting force created by a wing at varying Lift co-efficients, which you alter by changing the angle of attack of the wing.

EDIT: I suppose you could then go on to discuss the various concepts associated with your results. The stalling angle, the stalling velocity, the zero-lift angle. And you can also compare your results with the various postulations that great men made in their attempt to explain lift. For example, Lanchester, Newton, Rayleigh, Kutta & Joukowski, etc.

Incidentally, Kutta & Joukowsi's mathematical model was the most accurate, the other theorists were extremely off...

Reply 10

OP

Mush

This the the basic formula for the lifting force of a wing. V is the airflow velocity, L is the lifting force, c is the chord length(distance from leading edge to trailing edge), CL is the lift co-efficient, rho is fluid density. You could investigate the changing of the lifting force created by a wing at varying Lift co-efficients, which you alter by changing the angle of attack of the wing.

I think you are over-estimating the scope of an Advanced Higher Physics Investigation. I'm not certain I would have access to a device capable of measuring the density of the air in a way that is understandable by myself and I doubt I could rely on Met Office air densities for my area in my investigation. :confused:

I'll see what my Physics teacher says on Fri but I'm not sure!! :p:

Reply 11

Stevo the Victorious

I think you are over-estimating the scope of an Advanced Higher Physics Investigation. I'm not certain I would have access to a device capable of measuring the density of the air in a way that is understandable by myself and I doubt I could rely on Met Office air densities for my area in my investigation. :confused:

I'll see what my Physics teacher says on Fri but I'm not sure!! :p:

Indeed. Any investigation with aerofoils is quite ambitious for AH Physics.

What other aspect of 'airflow over aerofoils' were you hoping to investigate that wouldn't be too far fetched?

There aren't, I imagine, many practical experiments you could do in this area, or related areas, that don't rely on wind tunnel facilities.

Reply 12

OP

Mush

What other aspect of 'airflow over aerofoils' were you hoping to investigate that wouldn't be too far fetched?

Now there's the $1million dollar question!! :p:

I'm thinking possibly investigating how lift varies with angle of attack/properties of a specific aerofoil. :s-smilie:

I'd probably use three aerofoils of different geometric properties and investigate how they perform in terms of lift at different angles of attack. There should be a good deal of physics in that, I'd just need a surefire way of measuring lift so I can work out the co-efficient of lift for each of my aerofoils and then work out a relationship linking lift and angle of attack. That should be sufficient, I hope. :redface:

Reply 13

Stevo the Victorious

Now there's the $1million dollar question!! :p:

I'm thinking possibly investigating how lift varies with angle of attack/properties of a specific aerofoil. :s-smilie:

I'd probably use three aerofoils of different geometric properties and investigate how they perform in terms of lift at different angles of attack. There should be a good deal of physics in that, I'd just need a surefire way of measuring lift so I can work out the co-efficient of lift for each of my aerofoils and then work out a relationship linking lift and angle of attack. That should be sufficient, I hope. :redface:

And how are you going to manage such experiments without a wind tunnel?

Reply 14

OP

Mush

And how are you going to manage such experiments without a wind tunnel?

Who said I don't have a wind tunnel?? I can create scale replicas of aerofoils and use a garden blower with some grills to stabilize the airflow. That's what my Physics teacher told me I can do and I don't see anything catastrophically wrong with it. Possibly there will be more errors to deal with than I would wish but these things happen in any investigation. I don't believe they got wind tunnels perfected the first time they tried it.

Reply 15

Stevo the Victorious

Who said I don't have a wind tunnel?? I can create scale replicas of aerofoils and use a garden blower with some grills to stabilize the airflow. That's what my Physics teacher told me I can do and I don't see anything catastrophically wrong with it. Possibly there will be more errors to deal with than I would wish but these things happen in any investigation. I don't believe they got wind tunnels perfected the first time they tried it.

Large large large large large largeeee innaccuracies lol. But I suppose they don't care in AH physics, just as long as you put it at the end of your investigation *warning, may contain large errors*

Reply 16

OP