REFLECTOR: RAM air and a "cold box" intake

Sat Jul 8 18:29:32 CDT 2006

Have any of you ever heard of, or tried this?
http://musclebiplane.org/htmlfile/motor.htm
It re-routes the intake runners/plenum out of the oil sump to keep the
intake air cooler, according the the article.
Matt

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Message: 1
Date: Sat, 08 Jul 2006 18:15:31 +0000
From: "steve korney" <s_korney at hotmail.com>
Subject: Re: REFLECTOR: ram air
To: reflector at tvbf.org
Message-ID: <BAY101-F23D27DEABF457FC75134B1E7750 at phx.gbl>
Content-Type: text/plain; format=flowed

Hi Pat...

    I won't run my engine at full throttle on the ground, not even on
take-off until I get moving about 20 mph...
So, I use my ambient MP gauge reading with engine off, against my dynamic MP
gauge reading at 220 kts. ias WOT... If I were to add in the loss of any
restrictions in my induction system, then I would be getting more then 2
inches of Ram Air MP increase.  This way I eliminate any error in the gauge
and any losses through the system and only show net gain...I have a forward
facing intake system on my Glasair... Straight through the Airflow
Performance FM-200 into the intake manifold... No Filter on Ram Air...The
difference between filtered air and ram air is about 2.5 inches of MP at any
speed... That shows how bad my filtered air is working as far as performance
goes, but does a good job of keeping junk out of my engine.   I can live
with 28 MP inches of filtered air for take-off most places...  If I'm at Big
Bear on a hot day, I just open the ram air butterfly and I have an extra 2.5
inches for take-off..

Best... Steve

----Original Message Follows----
From: Pat Shea <xl340hp at yahoo.com>
Reply-To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Subject: Re: REFLECTOR: ram air
Date: Sat, 8 Jul 2006 01:18:26 -0700 (PDT)

Okay Steve,

So assuming you didn't go out on a standard day, what
reference did you use to determine your 2" of ram?

The local barometer reading?

Your ambient MP gauge reading?

I'm running a filtered induction. Here's a realistic
scenario: The local baro setting is 30.0". With my
engine off the MP on my Vision Microsystems gauge
reads 29.0". In the run-up area at WOT the gauge reads
28.0". I think that means I have a pressure loss of 1"
across my plumbing/filter. Now, during a high speed
pass down that runway at WOT my MP gauge reads 29.0".
That means I'm getting 1" of ram pressure right - just
enough to offset my plumbing/filter losses?

It seems to me that comparing your static WOT MP
reading to your MP reading during a high speed low
pass at WOT down that runway would be the most
accurate way to determine your true ram. This way you
eliminate any errors in you MP gauge calibration and
account for any restrictions in your induction system.

What's funny is that I hear a lot of people talk about
ram but not how they derive it. I suspect that it's
being derived lots of different ways and therefore not
easy to compare and contrast.

Pat

--- steve korney <s_korney at hotmail.com> wrote:

 > This little chart assumes std. day  :   sea level,
 > 29.92, and 59 f.
 > It's what the front of the airplane is up against at
 > different speeds...
 >
 > In my Glasair, I see up to 2 inches of ram pressure
 > on the manifold pressure
 > gauge at sea level @ 220 kts. ias....  ie. 32 inches
 > of manifold pressure on
 > a std. day...
 >
 > Best... Steve
 >
 >

_____
Message: 2
Date: Sat, 08 Jul 2006 18:24:50 +0000
From: "steve korney" <s_korney at hotmail.com>
Subject: Re: REFLECTOR: ram air
To: reflector at tvbf.org
Message-ID: <BAY101-F254BCC4DA8E63DA5866FA3E7750 at phx.gbl>
Content-Type: text/plain; format=flowed

By the way Pat...

That chart only shows Ram Pressure at a given speed....  It's not intended
to account for any losses in our systems... So, we can use it to determine
just how good our systems work compared to other systems out there, and all
we need is a MP gauge and airspeed indicator that's close to accurate and
has good resolution...