Wind Tunnel Moving Airfoil Test2

[Desmonddd2002]

what is the wind speed in ur tunnel, and what shape would u recommend the wind tunnel to be in? Also what is the dimension of ur wind tunnel. Thanks a lot because i have recently built mine and it didn't work that well :(

[nebg9]

@Desmonddd2002 The wind tunnel in this video had a contraction cone that went from a 25" diam intake to a 14" square test section. The speed in the video is about 5mph. This wind tunnel got up to about 30mph but at the higher speeds, the smoke dispersed too much to see. Good luck!

[phatstakz78]

aim the damn smoke directhly at the leading edge of the airfouil....when doing this you can finally demonstrated the flow of air during bernoullies principle....lol...

[dewaone]

Um, This was awesome, thank you!

[beymastang]

what did you used to make the smoke or fog ?

[tomcarlone]

@beymastang We filled a 2L soda bottle with warm water, dropped in some dry ice, and then screwed the cap back on. We modified the cap so that it fed directly to a narrow hose which was used as the wand to direct the 'smoke'

[beymastang]

what did you used to make the smoke or fog

[zalami12]

did YOU make this windtunnel? if so howd u set it up? how big is it?

[tomcarlone]

I would image you would get the same or similar result with any fluid medium. Our tunnel was made to only work with air so we did not test other fluids

[gernader8]

@tomcarlone

Assuming the wings chord, and and inflow velocity stayed the same, a different fluid would yield different results. This is due to the Reynolds number across the wing being different. However, if you scaled all your dimensions (chord, velocity, viscosity) properly, then you could achieve similar effects.

Great build though, I'd suggest investigating "wall effects" because of the small domain. It can dramatically change the flow across the wing!

[fundipiz]

@tomcarlone

i am doing the same kind of project but i need to know how u got the smoke to go in a straight line

please help!!!!!!!!!!!!!!!!!!!!! and could u tell me how to make the aircraft wing, air foil. also what produce the smoke

[nebg9]

@fundipiz the smoke is just introduced through a small tube right in front of the settling chamber. the smoke is sublimated dry ice.

and the wing is hotwire cut out of foam insulation.

[slayyer2003]

@tomcarlone THIS IS GREAT IT SHOWS WHEN THE WING STALLS

[priya8919]

does this thing show the same result in a fluid medium...such as oil or water?

[mrbeetham]

have you ever tried aiming the smoke at the thing? Duffus.

[LethalHobo]

Can you show different types of aerofoils.. in particular a laminar flow (p51 or A26 or something)? Also, it would be neat to see flaps up/down. Only problem is you cant see the smoke on the leeside of the wing. Maybe attach a piece of string to it?

[nabilhattaz]

hi tomcarlone, we have a 50m/s suction type wind tunnel. we want to do the flow visualization on various models, using a normal studia smoke generator. we tried connect the smoke gen to the smoke probe inside the test section using a high pressure tube. but the smoke condensed right away as soon as we on. can you tell me how can we fix this problem?

[2azool]

Have you tried the same experiment with a vortex traps thx good vedio

[DRaG0NREdZ]

Awesome video (and simulation)! Have you ever tried doing the same experience with a model aircraft?

[tomcarlone]

@DRaG0NREdZ Thanks, the airfoil shown in this video is from a foam model airplane wing. We are in the process of making more videos with some other models. Is there something in particular that you would like to see?

[DRaG0NREdZ]

@tomcarlone would it be possible to do an experiment with helicopters and wake turbulence?

[1aloosh]

i am currently building an airfoil, and the aifoil is made from aluminium. I have some problems with bending the aluminium on the leading edge, what material do you think is appropriate.

[nebg9]

@1aloosh There are many options depending on your particular application. If you want to do something similar to this demonstration, you should hot wire cut an airfoil out of a foam block. Or, you can build a balsa frame and cover it with lightweight covering. Fiberglass or carbon fiber may also be an option. If you are having problems bending the aluminum, you can make a solid aluminum leading edge.

[1aloosh]

@nebg9

thank you for your help :)

[andyskateboarder]

how u created the wing?

[tomcarlone]

I believe it was made of foam by hot-wire cutting it over a pre-made profile

[andyskateboarder]

how did u make the wing and its pulling wire? which materials are they made of?

[wasiur5000]

how did u create the smoke? i need to do the same for a science fair project. Thanks in advance

[mindhaze]

Uh, why don't you "google" that and get an immediate answer?

[tomcarlone]

I'm not exactly sure on your questions about dry ice...By sublimating solid C02 into a gas it is creating a mix of C02 and air cold enough to condense water vapor which results in the cloud you see. This effect goes away when the C02 is no longer cold enough to prevent the water droplets from evaporating back into water vapor, in my case this was about 12in past the object being tested, so it does not fog up the whole place. Also the fan used was a "FlowPro Premium 25in., 8400 CFM, Model# 11409"

[gsxcargi]

@tomcarlone

how did you get the dry ice to flow in such a condensed line? would you mind showing us your whole rig, including the fan and dry ice creater?

Im doing a science fair project and i need some help on creating a wind tunnel with smoke.

[josh2593]

can you make a video to show the set up of your wind tunnel plz????

[Mav1843]

That's not true in all cases. For example, traveling at 120 kts in a C172 and pull up, you can get to 20-22 degrees of pitch. So, It depends. Or, you would never see an aerobatic routine at your common airshow.

[pkt42]

The critical AoA depends on the design of the wing airfoil, but does not depend on airspeed. This is discussed in wikipedia article 'Stall_(flight)' (or check your training manuals on stalling).

Also be careful not to confuse angle of attack (relative to airflow) and pitch angle (relative to horizon) as these are different things.

[TheDasio]

when the aerofoil reaches 15 degrees or more it stalls due to the lack of laminent air over the top. as it is mostly if not all turbulent air

[tomcarlone]

ya, I got dry ice at a local welding shop. And you have the right idea about the angle of attack. When you can see the flow separate that is where the wing would stall. And ya the push rod and linkages are made from paper clips

[wasifyar]

did you make the push rod out of paper clip.lol. nice video btw

[muddwell]

so you have maximum angle of attack right, once above this you get separation which means the wing stops producing lift ?

[maryw10]

where would you get dry ice though?

[Questtechie]

grocery stores, gas supply places.

[maryw10]

HOW DID YOU DO THAT???????

ive been trying to get a decent wind tunnel made but its so hard to get the smoke to work plz help!!!!!!

[tomcarlone]

Ya, the smoke is defintely the hardest part. We used dry ice as smoke. Putting dry ice in warm water creates the most white smoke. We also used a 2L soda bottle with a tube coming from the cap as a way to control and direct the smoke which helped to make a tighter stream. The other trick is to run a very low air speed in the tunnel. In all of these videos the air speed is 1-3 mph, any faster would require significantly more smoke