X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-lb0-f182.google.com ([209.85.217.182] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with ESMTPS id 6365309 for flyrotary@lancaironline.net; Mon, 08 Jul 2013 21:39:52 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.217.182; envelope-from=alex.molteno@gmail.com Received: by mail-lb0-f182.google.com with SMTP id r11so4349711lbv.27 for ; Mon, 08 Jul 2013 18:39:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=bMF9HYudpydz5R6rWzuRnw7zxV6E6w0btlJuZuO9QiI=; b=YxIb3Bzf7DAnHOGuYHgsF2dyLldD4bERBNmDYMdQrzIdVbeYrNLeEvE3dRQrF24L84 yPlNTAOtqiyQSziPdXhUhT0nr2w9cwJ/biMQdlrWj+9hu48bruZ8GNFE3nvQ1fcs5MVz Ss7XRooC9xIItEtpN6Rf4kUYtbtr5Qz9nWmZiqmFxy4f9LNTePUEVsQvjywkawcxhXYB pF5WGrSW3iZRD798qeHOWbuvvzByMw7RXcOKUHk0UgxAlZH8jLcA1qBhmJ906z2gfgnF UInHq+hYRTb0WFkcchpty15YFeOOji3eChVLkFP5OW/Wjdl3loYBFVdyytp6zRMFBXYC dg5Q== MIME-Version: 1.0 X-Received: by 10.152.37.69 with SMTP id w5mr11668395laj.56.1373333955878; Mon, 08 Jul 2013 18:39:15 -0700 (PDT) Received: by 10.112.13.195 with HTTP; Mon, 8 Jul 2013 18:39:15 -0700 (PDT) Received: by 10.112.13.195 with HTTP; Mon, 8 Jul 2013 18:39:15 -0700 (PDT) In-Reply-To: References: Date: Tue, 9 Jul 2013 02:39:15 +0100 Message-ID: Subject: Re: [FlyRotary] Re: Ram Air and filters From: alex To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=089e0160ac8899244d04e10a3a26 --089e0160ac8899244d04e10a3a26 Content-Type: text/plain; charset=ISO-8859-1 Thanks Ken, Alex On Jul 8, 2013 11:51 PM, "Kenneth Johnson" wrote: > Alex, > Two years ago I decided on the filter route. I was able to go on line at > www.knfilters.com. I wanted to know what filter was recommended for my > 13B, without turbo. An agent responded with the main question as to what > size flange the filter would be attached. I was creating the flange and so > the size was not an issue. We decided on a 3 inch flange and the agent > responded that the K&N filter for me was RU-5111. The engine you are > using may require a different filter, but K&N can help you with the right > size. > > Because of the space I have under the cowl, I have mounted my filter in > the front opening of my fiberglass cowl. I created a dome shaped > fiberglass fitting to go over the rubber end of the filter, but > repositioned the filter, so I could not use it. > > One automotive adviser suggested that in a closed intake system, the > oxygen sensors and computer will make adjustments for any change in air > pressure. > That might be a point of discussion regarding another flapper door. I > will evaluated the proof of all this work when I first start my engine this > fall. > > Ken Johnson, building a Zenith 801 > > > > > > > ------------------------------ > *From:* alex > *To:* Rotary motors in aircraft > *Sent:* Monday, July 8, 2013 7:51 AM > *Subject:* [FlyRotary] Re: Ram Air and filters > > Thanks, it makes sense. > I think i will go the automatic route and put a flapper door somewhere > after the filter. > > Alex M > > On Sun, Jul 7, 2013 at 4:19 AM, wrote: > > ** > Alex > > Remembering back, It seems as if the manifold pressure, at WOT seemed to > be always less than ambient. Ram would increase that. Of course, a charger > (turbo or super) would increase the "ram" pressure even more. In Normally > aspirated, there are two types of alternate air. Manual controlled-- ie > levers and cables, etc, and automatic, which is exactly as you > described.(and what I will be using) > > The usual and critical part of the induction system for blockage seems to > be between the air inlet and the filter. The "flapper: door generally has a > light spring holding it closed. Remember that the throttle plate is > downstream of the filter. When the throttle plate is open, the flowing > air between the plate and the trochoids (of course that part of the > induction system downstream of the plate) has the least resistance and > thus the MP is the highest-- going near but not to ambient. As the plate is > closed, the little trochoids are sucking against a partially closed orifice > and the MP goes down. (of course, the MP is measured between the plate and > the trochoid intake port. > > The intake manifold pressure upstream of the throttle plate does not > suffer the same fate, as a matter of fact, logic (who says that is right) > says that the pressure in that part of the manifold might even be inversely > affected. > > Now if you have a blockage before the alternate air flapper (assuming > automatic, the trochoids are sucking against that blockage making the > pressure in the plenum between the blockage and the throttle plate decrease > below ambient, the door swings inward (high ambient vs low internal) and > the engine can still breathe. > > In the planes that I have had with the automatic alternate air, if memory > serves me correctly(no guarantees) the flapper plate was part of the air > cleaner assembly. > > Rich > > > In a message dated 7/6/2013 8:41:40 P.M. Central Daylight Time, > alex.molteno@gmail.com writes: > > Ya don't want to pay the fuel or maintenance on anything burning > kerosene..I take your point on less airflow. Can you tell me which pressure > is greater in the intake manifold, the influence of ram air pressure or > intake vacuum pressure. Or does it vary from one to the other according to > the cycle. > > For an "automatic" homegrown system on a 2 rotor would it work to have a > spring loaded door opening inward into the intake manifold, fed by interior > cowling air when the main system is blocked. It makes sense to me to have a > door open for a negative pressure in the intake manifold which i imagine > would be the case of a blocked regular air intake and ongoing intake vacuum > pressure. Would a door like this be kept shut under normal conditions of > positive ram air, to preserve ram air which is what we want? > > Alex M > > On Sun, Jul 7, 2013 at 12:08 AM, wrote: > > ** > Interesting concept, I can see how that would eliminate a lot of FOD, > however that is not how alternate air systems work for piston/rotor type > engines. > > That is almost the reverse. My guess is that the airflow in the PT6 is > hughly greater than in a 2 or 3 rotor engine and the kinetic energy of the > FOD is significantly less. Additionally, the alternate air is to allow air > to flow if the induction system gets blocked. this valve works in the > reverse. The greater the pressure upstream the more it will open and in > fact will vent the presure (FOD/rain etc) overboard > > If the intake becomes blocked as in a filter or induction icing, the > pressure is reduced tending to seal the manifold.at this valve. > > Would that we could all fly Turboprops > > Rich > > In a message dated 7/6/2013 1:12:11 P.M. Central Daylight Time, > alex.molteno@gmail.com writes: > > Hello Lynn > > Are you referring to a similar system you see on the Pratt and Whitney PT6 > series engine, basically reversing the flow of air 180 degrees before > entering the compressor (throttle body for us i guess). The inertia of the > FOD or ice particles doesn't let them "make the turn" into the throttle > body and they exit the duct via a bypass flap. In this case the opening of > the flap creates the 180 degree turn and spillover air exit? > > Alex M > > > > > > --089e0160ac8899244d04e10a3a26 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

Thanks Ken,

Alex

On Jul 8, 2013 11:51 PM, "Kenneth Johnson&q= uot; <kjohnsondds@yahoo.com= > wrote:
Alex,
Two years ago I decided on the filter route.=A0 I was abl= e to go on line at w= ww.knfilters.com.=A0 I wanted to know what filter was recommended for m= y 13B, without turbo.=A0 An agent responded with the main question as to wh= at size flange the filter would be attached.=A0 I was creating the flange a= nd so the size was not an issue.=A0 We decided on a 3 inch flange and the a= gent responded that the K&N filter for me was RU-5111.=A0=A0 The engine= you are using may require a different filter, but K&N can help you wit= h the right size.

Because of the space I have under the cowl, I have mounted my filter in= the front opening of my fiberglass cowl.=A0 I created a dome shaped fiberg= lass fitting to go over the rubber end of the filter, but repositioned the = filter, so I could not use it.=A0

One automotive adviser suggested that in a closed intake system, t= he oxygen sensors and computer will make adjustments for any change in air = pressure.
That might be a point of discussion regarding another flapper = door.=A0 I will evaluated the proof of all this work when I first start my = engine this fall.

Ken Johnson, building a Zenith 801






From: alex <alex.molteno@gmail.com>
To: Rotary motors in aircraft <flyrotary@lanc= aironline.net>
Sent: Monday, July 8, 2013 = 7:51 AM
Subject: [FlyRot= ary] Re: Ram Air and filters

Thanks, it ma= kes sense.=A0
I think i will go the automatic route and put a flapper door somewhere afte= r the filter.=A0

Alex M

<= div>On Sun, Jul 7, 2013 at 4:19 AM, <ARGOLDMAN@aol.com> wrote:
Alex
=A0
Remembering back, It seems as if the manifold pressure, at WOT seemed = to be=20 always less than ambient. Ram would increase that. Of course, a charger (tu= rbo=20 or super) would increase the "ram" pressure even more. In Normall= y aspirated,=20 there are two types of alternate air. Manual controlled-- ie levers and cab= les,=20 etc, and automatic, which is exactly as you described.(and what I will be= =20 using)
=A0
The usual and critical part of the induction system for blockage seems= to=20 be between the air inlet and the filter. The "flapper: door generally = has a=20 light spring holding it closed. Remember that the throttle plate is downstr= eam=20 of=A0 the filter. When the throttle plate is open, the=A0flowing=20 air=A0between the plate and the trochoids (of course that part of the=20 induction system downstream of the plate) has the least resistance=A0 and= =20 thus the MP is the highest-- going near but not to ambient. As the plate is= =20 closed, the little trochoids are sucking against a partially closed orifice= and=20 the MP goes down. (of course, the MP is measured between the plate and the= =20 trochoid intake port.
=A0
The intake manifold pressure upstream of the throttle plate does not s= uffer=20 the same fate, as a matter of fact, logic (who says that is right) says tha= t the=20 pressure in that part of the manifold might even be inversely affected.
=A0
Now if you have a=A0blockage before the alternate air flapper (assumin= g=20 automatic, the trochoids are sucking against that blockage making the press= ure=20 in the plenum between the blockage and the throttle plate decrease below=20 ambient, the door swings inward (high ambient vs low internal) and the engi= ne=20 can still breathe.
=A0
In the planes that I have had with the automatic alternate air, if mem= ory=20 serves me correctly(no guarantees) the flapper plate was part of the air cl= eaner=20 assembly.
=A0
Rich
=A0
=A0
Ya don't=20 want to pay the fuel or maintenance on anything burning kerosene..I take = your=20 point on less airflow. Can you tell me which pressure is greater in the i= ntake=20 manifold, the influence of ram air pressure or intake vacuum pressure. Or= does=20 it vary from one to the other according to the cycle.=A0=20

For an "automatic" homegrown system on a 2 rotor would it = work to have a=20 spring loaded door opening inward into the intake manifold, fed by interi= or=20 cowling air when the main system is blocked. It makes sense to me to have= a=20 door open for a negative pressure in the intake manifold which i imagine = would=20 be the case of a blocked regular air intake and ongoing intake vacuum=20 pressure. Would a door like this be kept shut under normal conditions of= =20 positive ram air, to preserve ram air which is what we want?=20

Alex M

On Sun, Jul 7, 2013 at 12:08 AM, <ARGOLDMAN@aol.com> wrote:
Interesting concept, I can see how that would eliminate a lot of F= OD,=20 however that is not how alternate air systems work for piston/rotor typ= e=20 engines.
=A0
That is almost the reverse. My guess is that the airflow in the PT= 6 is=20 hughly greater than in a 2 or 3 rotor engine and the kinetic energy of = the=20 FOD is significantly less. Additionally, the alternate air is to allow = air=20 to flow if the induction system gets blocked. this valve works in the= =20 reverse. The greater the pressure upstream the more it will open and in= fact=20 will vent the presure (FOD/rain etc) overboard
=A0
If the intake becomes blocked as in a filter or induction icing, t= he=20 pressure is reduced tending to seal the manifold.= at this valve.
=A0
Would that we could all fly Turboprops
=A0
Rich
=A0
In a message dated 7/6/2013 1:12:11 P.M. Central Daylight Time, alex.molteno@gmail.com writes:<= /div>
Hello Lynn=20

Are you referring to a similar system you see on the Pratt and= =20 Whitney PT6 series engine, basically reversing the flow of air 180 de= grees=20 before entering the compressor (throttle body for us i guess). The in= ertia=20 of the FOD or ice particles doesn't let them "make the turn&= quot; into the=20 throttle body and they exit the duct via a bypass flap. In this case = the=20 opening of the flap creates the 180 degree turn and spillover air=20 exit?

Alex=20 M

=




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