[NSRCA-discussion] Wind tunnel

[Jay Marshall]

I don't know about smoke generators but I do know that the air is "pulled"
over the surface. Wouldn't you need a clear cowl to se how it flows around
the engine? Or perhaps some miniature pressure sensors?
 
-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Earl Haury
Sent: Tuesday, January 23, 2007 2:53 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Wind tunnel
 
I experimented with looking at cooling air flow using smoke with limited
success. Airflow can be simulated with fans & cardboard flow straighteners /
aircraft prop - motor (be careful) - and even leaf blowers / shop vac exits
with varying degrees of success. A mini - webcam mounted in a fuselage (with
lighting) provides some view of smoke flow inside a closed fuse.
 
However - making enough non - corrosive or non - oily smoke (at a reasonable
price)  is an issue. Most of the smoke "wands" produce a corrosive element
in the smoke.  Most of the smoke generators produce an oily smoke that
leaves an oily residue. I don't want either in my airplane / equipment. 
 
The best I found are smoke "pens" used in the HVAC service industry - they
consist of a wax impregnated wick that smokes similar to an extinguished
birthday candle. Unfortunately, the amount of smoke is limited and becomes
diluted (invisible) at the airflows we'd like to investigate. These were
useful in determining the shape / edge of air inlets so that minimum air was
diverted around the inlets.
 
Earl
----- Original Message ----- 
From: Mark <mailto:atwoodm at paragon-inc.com>  Atwood 
To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>  
Sent: Tuesday, January 23, 2007 1:26 PM
Subject: Re: [NSRCA-discussion] Wind tunnel
 
I speak from VERY limited experience, however the simple version appears to
be to "pull" the air over the surface rather than push it.  They used a
large fan to evacuate the room and provided small controlled inlets for air
to enter and flow over the surface.  The smoke is simply from colored smoke
sticks, though I'm not sure of the source of those.  

I'm curious though how representative that is of the actual "Flow" over the
object.  


On 1/23/07 2:17 PM, "J.Oddino" <joddino at socal.rr.com> wrote:
Anyone know what they use in those automobile ads that shows how the air
flows over their slick streamlined cars?
I was thinking one might determine what the cooling airflow looked like
around and through our electric motors.

Jim O

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