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Date: Mon, 29 Aug 2011 14:52:39 -0700
Message-ID: <CAMOiWoPn1zqy+uLOROMrNPG0WDUh4CMLWFw7cT7AZjxH9CkgFA@mail.gmail.com>
Subject: Re: [FlyRotary] Re: Props
From: Pat Panzera <editor.contactmagazine@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Content-Type: multipart/alternative; boundary=20cf3005147aff864904ababe93a

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An article by Paul Lipps:
http://www.eaa.org/experimenter/articles/2009-02_elippse.asp



On Sun, Aug 28, 2011 at 9:12 PM, Scott Emery <shipchief@aol.com> wrote:

> Paul Lipps designs some radical props. He has a convincing argument in
> favor of more blades but less diameter. Less dia. Means less torque arm for
> tip drag / blade. More blades : more thrust.
>
> Sent from my iPhone
>
> On Aug 25, 2011, at 2:45 PM, Dale_R <dale.rog@gmail.com> wrote:
>
> I can't speak from direct experience - yet - but the reason I'm planning on
> a Hertzler Silver Bullet is that several people have found that Gary's two
> blade had outperformed the Catto they had made for the same application.
> For example, Marc Zeitlin found he liked his new Silver Bullet better than
> the three blade that he'd had before.
>
> Problem is, one of those "other factors" is that for any given output, two
> blade usually has to be longer than a three blade.  Too long on a pusher and
> it gets trimmed automatically on your first high-angle-of-attack landing.
>
> Dale_R
> COZY MkIV #0497
>
>
> On 8/25/2011 1:53 PM, Tracy wrote:
>
> Most efficient would be 2 blades.   other factors may favor more blades but
> that's a different question.
>
> Tracy
>
> On Thu, Aug 25, 2011 at 4:25 PM, Samuel Treffinger <<samuel.treffinger@gmail.com>
> samuel.treffinger@gmail.com> wrote:
>
>> Hey, what would you recommend? A three or four blade prop? It will be
>> wood, so weight isnt such an issue, but which is more efficient given the
>> same power?
>>
>> Sam
>>
>
>
>
> --
> Dale_R
> Cozy MKIV #497
>
>

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An article by Paul Lipps:<div><a href=3D"http://www.eaa.org/experimenter/ar=
ticles/2009-02_elippse.asp">http://www.eaa.org/experimenter/articles/2009-0=
2_elippse.asp</a><div><br><br></div><div><br><div class=3D"gmail_quote">On =
Sun, Aug 28, 2011 at 9:12 PM, Scott Emery <span dir=3D"ltr">&lt;<a href=3D"=
mailto:shipchief@aol.com">shipchief@aol.com</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex;"><div bgcolor=3D"#FFFFFF"><div>Paul Lipps de=
signs some radical props. He has a convincing argument in favor of more bla=
des but less diameter. Less dia. Means less torque arm for tip drag / blade=
. More blades : more thrust.</div>
<div><br>Sent from my iPhone</div><div><div></div><div class=3D"h5"><div><b=
r>On Aug 25, 2011, at 2:45 PM, Dale_R &lt;<a href=3D"mailto:dale.rog@gmail.=
com" target=3D"_blank">dale.rog@gmail.com</a>&gt; wrote:<br><br></div><div>=
</div>
<blockquote type=3D"cite"><div>
    I can&#39;t speak from direct experience - yet - but the reason I&#39;m
    planning on a Hertzler Silver Bullet is that several people have
    found that Gary&#39;s two blade had outperformed the Catto they had mad=
e
    for the same application.=A0 For example, Marc Zeitlin found he liked
    his new Silver Bullet better than the three blade that he&#39;d had
    before.<br>
    <br>
    Problem is, one of those &quot;other factors&quot; is that for any give=
n
    output, two blade usually has to be longer than a three blade.=A0 Too
    long on a pusher and it gets trimmed automatically on your first
    high-angle-of-attack landing.<br>
    <br>
    Dale_R<br>
    COZY MkIV #0497<br>
    <br>
    <br>
    On 8/25/2011 1:53 PM, Tracy wrote:
    <blockquote type=3D"cite">Most
      efficient would be 2 blades.=A0=A0 other factors may favor more blade=
s
      but that&#39;s a different question.<br>
      <br>
      Tracy<br>
      <br>
      <div class=3D"gmail_quote">On Thu, Aug 25, 2011 at 4:25 PM, Samuel
        Treffinger <span dir=3D"ltr">&lt;<a href=3D"mailto:samuel.treffinge=
r@gmail.com" target=3D"_blank"></a><a href=3D"mailto:samuel.treffinger@gmai=
l.com" target=3D"_blank">samuel.treffinger@gmail.com</a>&gt;</span>
        wrote:<br>
        <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border=
-left:1px #ccc solid;padding-left:1ex">
          <div>Hey, what would you recommend? A three or four blade
            prop? It will be wood, so weight isnt such an issue, but
            which is more efficient given the same power?</div>
          <div>=A0</div>
          <div>Sam</div>
        </blockquote>
      </div>
      <br>
    </blockquote>
    <br>
    <br>
    <pre cols=3D"72">--=20
Dale_R
Cozy MKIV #497
</pre>
 =20

</div></blockquote></div></div></div></blockquote></div><br></div></div>

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