REFLECTOR: Nose Cooler Pressure Study

[Brent Bourgeois]

Jon,
I have the arm pit scoops.  Probably slightly smaller than the plans call for. Built them big before understanding what I was doing.  Lots of testing and I have CHT probes under the cylinder and under the top plugs for measurment. IO 360-A1A

Brent 

N61VB

Std RG

--- On Sat, 10/10/09, Bachman, Jonathan <Jonathan.Bachman at mtsi-va.com> wrote:


From: Bachman, Jonathan <Jonathan.Bachman at mtsi-va.com>
Subject: Re: REFLECTOR: Nose Cooler Pressure Study
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Date: Saturday, October 10, 2009, 9:15 PM








Brent,
 
What kind of engine cooling inlets do you have?  I have under wing (not arm pit type) and think they are not very efficient.
 
Jon
N956DR
1992 Std RG
 




From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Brent Bourgeois
Sent: Saturday, October 10, 2009 6:59 PM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Nose Cooler Pressure Study
 







Scott,

I have spent a lot of time getting my oil cooler working properly. Before cutting anything, please do a basic pressure study to understand what is going on. All you need is a plastic tube about 1 inch in front of the cooler and one in the exit duct. Route them inside and use a airspeed indicator to get an inlet press and an outlet press. The key is to maximize the differential.  

I have pages of data that prove (at least on my plane ) that the problem is positively not getting the air in, but getting it out. 

One example is : 155mph on the pitot, 88mph on the cooler face and 10 mph in the exit duct. I was eventually able to get the exit duct to 0. This 88mph proved to be the max oil cooler inlet speed all the way past 220 pitot speed. 

I think that once the inlet pressures up, the air stops entering and flows on by. Once I got max vacuum possible behind the cooler I was able to block off some of the (weird NACA type)  inlet and not raise the oil temp.

I believe the trick is to find a reverse scoop or lip arrangement that maximizes the air extraction

I had thermocouples on the cooler inlet and outlet lines. The front cooler is worth 15 to 20 degrees in oil temp.

I also found this method very useful at maximizing engine cooling while making the air inlets smaller. 

Let me know if I can help.

 

Brent 

N61VB

Std RG

 

 

 

 

 
 
-----Inline Attachment Follows-----


_______________________________________________
To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html


      
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20091010/01d671b1/attachment.htm>