REFLECTOR: Induction scoop

[Jon Bachman]

I'm interested in the spreadsheet too.

Jon Bachman
N956DR

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of W J Wilbeck
Sent: Tuesday, July 07, 2009 1:43 PM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Induction scoop

John

I would like to see your spreadsheet.

Engine Induction & Scoop of great importance to me with a Franklin Engine.

wj
N173WJ

W J Wilbeck

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of John Tvedte
Sent: Tuesday, July 07, 2009 1:47 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Induction scoop

Scott,

I have an IO-540K  - so approx. 422 CFM.  K&N filter media flows at 6 CFM/Sq
in of 2 dimensional surface area - so one would calc. approx. 70 Sq In of
filter required.  Don @ Airflow suggested 100-130 SqIn - to keep pressure
drop to a minimum at altitude (assuming we would use K&N filter media).

Rene uses a RB-0910 round filter - @ 70.65 Sq In (260 HP IO540)
Pat Shea uses a E-2940 Oval Filter @ 88 Sq In (300 HP+ IO540K)

Ken Parser - Author "Speed with Economy" - suggests using an inlet size 10%
greater than the throat of the servo.

You should expand at 7deg (max 15 deg) included angle to at least twice the
area of the inlet prior to hitting the filter.

I'm going to use an RF-1046 Conical filter - @ approx. 125 Sq In.

If you're interested I have a spreadsheet with calcs, filters etc.


John

________________________________________
From: reflector-bounces at tvbf.org [reflector-bounces at tvbf.org] On Behalf Of
Scott Derrick [scott at tnstaafl.net]
Sent: Tuesday, July 07, 2009 1:26 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Induction scoop

The scoop size vs the filter size seem at odds with each other.

Per this engine air/flow site my io520 at 2700 RPM, assuming volumetric
efficiency is 100%(yeah right!) is 406 CFM(not 460)

http://www.stealth316.com/2-air-fuel-flow.htm

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Per this air flow calculator site for 406 CFM at 130 mph, would require
a scoop opening of a tad smaller than 1x6 inches or 6 sq inches.  With
that size opening, I'm dumping 350 CFM at 200 MPH which basically
translates to a flat plate resistance of 6 sq inches or the size of the
opening..

http://www.comairrotron.com/airflow_calc.shtml

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Per K&N's filter size equation  Area = (CID X RPM)/20,839  says I will
need 65 sq inches of filter!

http://www.knfilters.com/filter_facts.htm#SELECT

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