Wind tunnel

[biziedizie]

Hey guys I've been messing with a scratch and it's a very odd looking design. The cp and cg will be fine but I've been thinking about how this rocket will fly as in will the fins work and things like that.
Anyways here's the question! I'm thinking about building a wind tunnel and I have everything to do this and was wondering what you guys think.
Good idea? Bad idea? Should I stop thinking and get a life? I'm thinking along the lines of being able to watch a rocket fly in a controlled space and being able to make adjustments as needed.


Steve

 

[jflis]

I would have to see your design before I could offer any comment...

 

[biziedizie]

I guess my line of thought is when we see a rocket go up and sometimes wobble a bit I'm thinking that it would it be a great advantage to see it fly before it goes up? If I could see it in flight in a wind tunnel then I could perfect the flight. I could add nose weight or add it to the back or do what ever it takes.
I'm thinking that it would be neat to see the rocket in motion and see how it does under the airfow even though it's not under power.
Just some thoughts........just some thoughts


Steve

 

[Silverleaf]

I'm with Jim, as usual..lol

Such a project would be interesting, if only so you'd have a place on those really hot days to lay and feel like your flying, AND be the envy of everyone else whos roasting..8)

 

[DynaSoar]

Originally posted by biziedizie
Hey guys I've been messing with a scratch and it's a very odd looking design. The cp and cg will be fine but I've been thinking about how this rocket will fly as in will the fins work and things like that.
Anyways here's the question! I'm thinking about building a wind tunnel and I have everything to do this and was wondering what you guys think.
Good idea? Bad idea? Should I stop thinking and get a life? I'm thinking along the lines of being able to watch a rocket fly in a controlled space and being able to make adjustments as needed.


Steve

How could it possibly be a bad idea? Worst case, it won't work, you can figure out why, and either fix it or at least tell the story so someone else can benefit from your experience. Best case, it'll work so well that people will bring their birds to you for testing.

I've been saving paper towel tubes for 6 months for a laminar flow chamber for the one I'm planning. A three stage turbine made from 3 cheap 20" window fans should give it a pretty good blast.

 

[jetra2]

Well...I have one thought before any of us are able to see your design.

I think that, but I'm not sure, that to accurately simulate the flight, you might want to consider making it so the fan can go from no-speed to high-speed then taper down to low-speed. Reason I say this is because the rocket never moves at the same speed during flight for more than maybe a 1/10 of a second...

Jason

 

[Elapid]

if you want to move air...

look at units from elicent or hurricane (i think that's the model, not the manufacturer...)

these inline duct blowers move upward of 150 cfm through a 4" duct, not sure what that works out to in mph or fps offhand...that's what reference manuals are for anyway!

they make them well over 12" in diameter and thousands of cfm.

you'll need smoke to see where your problem areas are. probably the easiest thing is to pick up a used theatrical smoke machine which uses a light oil to create non-toxic smoke. IIRC, they are about 100 bux new, so a used one should be fairly cheaply.

for laminar flow, i'd think that the larger the tube used, the longer it needs to be to work well. i'm leaning toward McDonald's drinking straws due to the large (relatively speaking) diameter and availability.

for the tunnel itself, it needs at least one clear side for observations and photography/video. it also needs an apparatus to securely hold the rocket at the CG while allowing the rocket freedom of movement along at least two axes...


nope...i've never given it much thought!

 

[BobH48]

Estes published an article with plans for building a wind tunnel back in 1961.

look here:

https://www.esteseducator.com/cfusion/publications.cfm

It's included in the PDF titled: Classic Collection

They stated that it produced a velocity of 22 ft / sec. which was sufficient for checking stability but flow-velocity was too low for checking drag.

I'm sure someone on this forum could figure out a way to increase the output.

 

[BobH48]

Estes published an article with plans for building a wind tunnel back in 1961.

look here:

https://www.esteseducator.com/cfusion/publications.cfm

It's included in the PDF titled: Classic Collection

They stated that it produced a velocity of 22 ft / sec. which was sufficient for checking stability but flow-velocity was too low for checking drag.

I'm sure someone on this forum could figure out a way to increase the output.