REFLECTOR: Oil cooler VG photo

[Dave Nelson]

I do have logs of outside air temp vs. oil temp over various configurations 
& with a "standard" flight profile.  I've also logged things like cooler 
outside temp (measured with an IR temperature probe).  Oil inlet and outlet 
temp I don't have - more difficult to get.  The most valuable thing would 
actually be inlet and exit oil pressure to the cooling loop (at least that's 
why my Lycoming contact would like to see most).  I agree that pursuing this 
kind of issue requires collecting good, repeatable data.

I've also done oil flow studies, which are the equivalent of tufting. 
Basically, you smear dirty oil over your pretty airplane and go flying. 
When you land, you can see where the air is attached, etc.  What that shows 
is good attachment in the area of the oil cooler NACA scoop, and pretty good 
attachment leading to the armpit scoops.  Interestingly enough, there is 
evidence of air backing up in the armpit scoops, meaning that they could be 
reduced further.  I haven't pursued that since CHTs are running fine.

Dave
----- Original Message ----- 
From: "Brian Michalk" <michalk at awpi.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Sunday, July 16, 2006 1:07 PM
Subject: Re: REFLECTOR: Oil cooler VG photo


>I always wonder, when I hear of the problems people have had.  I've
> never seen the data that's conclusive.
>
> Most times the data is conflicting.  Two seemingly identical
> installations; one no problem, the other big problems.
>
> It sounds like you've done a lot of work here.
> I would like to see the temperatures and flows associated with the oil
> cooler.  Should be simple.  I'm only asking for four parameters:
> 1) Outside Air temp
> 2) Cooler exhaust air temp
> 3) Oil inlet temp
> 4) Oil outlet temp
>
> nice to have:
> 5) Oil flow
> 6) Air flow
>
> In everything I've seen on the reflector, I have never come across
> anyone that has information on all these parameters.  I've seen lots of
> modifications that have claimed benefits, but then there's no data that
> we can look at to tell which parameter change provided the benefit.
>
> It's frustrating.  I'm still building, and have no right to tell others
> they are doing us builders a disservice.  There's just a dearth of good
> information.  Heck, even just basic tuft testing.  I'm only aware of (I
> think) Sid Knox that did tufting on his V.  That's the kind of stuff I'm
> looking for.  It's cheap, yet very few people seem willing to put in the
> effort to gather good data.
>
> When I think "experimental aircraft", this is the image that comes to
> mind.  Yeah, you can go places too for those $140 (inflation) hamburgers.
>
> I hope when I'm flying I still have the inclination to collect this data
> and share it with the rest so they can make better airplanes.
>
> Dave Nelson wrote:
>> Thanks much for the tips, Scott - and for the speedy response.  Here's 
>> more
>> background...
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