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Date: Tue, 12 Apr 2005 21:02:05 -0500
Subject: Re: [FlyRotary] Re: Ram and Alt air
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From: Jerry Hey <jerryhey@earthlink.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
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All the better.  I believe that someone who is NEVER WRONG on some=20
other list, told me it was 3 inches.   Thanks Tracy.    Jerry


On Wednesday, April 13, 2005, at 07:50 PM, Tracy Crook wrote:

> FWIW, my current scoop is 2.125" in diameter.
> =A0
> Tracy
>
>
> I have not actually studied the ideal ram scoop opening. I know that
> Tracy is using a 3inch dia round=A0 scoop that would have about 7 =
inches
> of area, just a little smaller than the scoop I proposed.=A0 I want to
> keep the scoop as low as possible while retaining the performance.=A0 =
The
> snouts that stick up into the air are not the look I want.=A0 Does the
> scoop get smaller with a higher top end?=A0 What would it be for 240 =
mph?
> =A0=A0=A0 Jerry
>
>
> On Tuesday, April 12, 2005, at 06:19 PM, Al Gietzen wrote:
>
> >
> > Here is pic of the plenum (at this point a piece of 1/4 inch ply.=A0=20=

> The
> > ram air scoop will be 4 inches wide and=A0 two inches high.
> >
> > Jerry:
> >
> > Is the 2" x 4" the opening size?=A0 I think that is more than double=20=

> the
> > area
> > that would give the amount of ram air needed for a 2-rotor at, say,
> > 120 kts.
> > So it will be spilling air and likely cause some amount of unwanted
> > drag.
> > Ideally, a ram induction scoop is close to the area needed for near=20=

> top
> > speed; and have radius on the entrance lip (about that of your index
> > finger)
> > to minimize entrance loss when you are at low speed.
> >
> > FWIW, I have no idea it any of this matters for what you're doing.
> >
> > Al
> >
> >
> >>>=A0 Homepage:=A0 http://www.flyrotary.com/
> >>>=A0 Archive:=A0=A0 =
http://lancaironline.net/lists/flyrotary/List.html
> >
>
>
> >>=A0 Homepage:=A0 http://www.flyrotary.com/
> >>=A0 Archive:=A0=A0 =
http://lancaironline.net/lists/flyrotary/List.html
>

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All the better.  I believe that someone who is NEVER WRONG on some
other list, told me it was 3 inches.   Thanks Tracy.    Jerry


On Wednesday, April 13, 2005, at 07:50 PM, Tracy Crook wrote:


<excerpt>FWIW, my current scoop is 2.125" in diameter.

=A0

Tracy


I have not actually studied the ideal ram scoop opening. I know that

Tracy is using a 3inch dia round=A0 scoop that would have about 7 inches

of area, just a little smaller than the scoop I proposed.=A0 I want to

keep the scoop as low as possible while retaining the performance.=A0 =
The

snouts that stick up into the air are not the look I want.=A0 Does the

scoop get smaller with a higher top end?=A0 What would it be for 240 =
mph?

=A0=A0=A0 Jerry


On Tuesday, April 12, 2005, at 06:19 PM, Al Gietzen wrote:


>

> Here is pic of the plenum (at this point a piece of 1/4 inch ply.=A0
The

> ram air scoop will be 4 inches wide and=A0 two inches high.

>

> Jerry:

>

> Is the 2" x 4" the opening size?=A0 I think that is more than double
the

> area

> that would give the amount of ram air needed for a 2-rotor at, say,

> 120 kts.

> So it will be spilling air and likely cause some amount of unwanted

> drag.

> Ideally, a ram induction scoop is close to the area needed for near
top

> speed; and have radius on the entrance lip (about that of your index

> finger)

> to minimize entrance loss when you are at low speed.

>

> FWIW, I have no idea it any of this matters for what you're doing.

>

> Al

>

>

>>>=A0 Homepage:=A0
<underline><color><param>1999,1999,FFFF</param>http://www.flyrotary.com/

</color></underline>>>>=A0 Archive:=A0=A0
=
<underline><color><param>1999,1999,FFFF</param>http://lancaironline.net/li=
sts/flyrotary/List.html

</color></underline>>


>>=A0 Homepage:=A0
<underline><color><param>1999,1999,FFFF</param>http://www.flyrotary.com/

</color></underline>>>=A0 Archive:=A0=A0
=
<underline><color><param>1999,1999,FFFF</param>http://lancaironline.net/li=
sts/flyrotary/List.html

</color></underline>

</excerpt>=

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