X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.4) with ESMTP id 4173348 for flyrotary@lancaironline.net; Sun, 21 Mar 2010 03:03:34 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id B9318173815 for ; Sun, 21 Mar 2010 15:02:54 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id C97DBBEC04E for ; Sun, 21 Mar 2010 15:02:52 +0800 (WST) Message-ID: <9161AB8595B444D1A6E6450625BD39DA@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" Subject: Fw: [FlyRotary] Date: Sun, 21 Mar 2010 17:03:08 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001D_01CAC918.61784330" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100320-1, 03/20/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_001D_01CAC918.61784330 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al/ Chris, I'm certainly no expert on Turbo, nor are some who purport to be = experts. There are those who are genuinely very knowledgeable in car = turbo, but for aircraft use it's another matter entirely. From discussions on here and other sites, it would appear to me that = Turbos fail because of the high heat at high rpm over extended periods = and the overspinning in thin air at altitudes. All that sounds fair and = reasonable to me. Some builders have overcome these problems by trimming internal blades = and making the waste gate as big as possible - in other words making the = internals so that the exhaust has more room to escape, placing less = stress on the turbo. I notice that some car applications have remote turbo allowing the = exhaust gasses to slow and cool before entering the turbo. For our = application we don't need all the energy from the exhaust, so we don't = need all that heat and exhaust pulses hammering the turbo, as it does = continuously if it's in close proximity to the engine. For my application, if I need turbo, I will place the turbo remotely and = only bypass enough exhaust energy, by way of a 'Y' section in the = exhaust pipe, to the turbo. The bypass should be cockpit adjustable for = different applications requiring different energy requirements - as in = the wategate.. Hope you see some merit in my thinking. George ( down under) =20 I know you're fairly entrenched in the 13B approach, but for the sake of = discussion, I'm not sure that's a valid reason. How high do you want to go? I think Tracy's been over 15k with an NA=20 13B. I'd be willing to bet that a Velocity with an NA 20B could get well = over 18k without a problem. As I recall my analysis those many years ago; the cross over point on = power for a turbo-normalized 13B and a NA 20B is at about 13,500' msl. = Above that altitude the torbo 13B will do better. Of course you can = boost the 13B to more than 30" and get more power. Al ------=_NextPart_000_001D_01CAC918.61784330 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Al/ Chris,

I'm certainly no expert on Turbo, = nor are some=20 who purport to be experts. There are those who are genuinely very=20 knowledgeable in car turbo, but for aircraft use it's another = matter=20 entirely.

From discussions on here and other = sites, it would=20 appear to me that Turbos fail because of the high heat at high = rpm over=20 extended periods and the overspinning in thin air at altitudes. All that = sounds=20 fair and reasonable to me.

Some builders have overcome these = problems by=20 trimming internal blades and making the waste gate as big as = possible=20 - in other words making the internals so that the exhaust has more room = to=20 escape, placing less stress on the turbo.

I notice that some car = applications have=20 remote turbo allowing the exhaust gasses to slow and cool before = entering the=20 turbo. For our application we don't need all the energy from the = exhaust, so we=20 don't need all that heat and exhaust pulses hammering the = turbo, as it does continuously if it's in close = proximity to the=20 engine.

For my application, if I need turbo, I=20 will place the turbo remotely and only bypass enough exhaust = energy, by way=20 of a 'Y' section in the exhaust pipe, to the turbo. The bypass should be = cockpit=20 adjustable for different applications requiring different energy = requirements -=20 as in the wategate..

Hope you see some merit in my=20 thinking.

George ( down under)

I=20 know you're fairly entrenched in the 13B approach, but for the sake of=20

discussion, I'm not sure that's a valid=20 reason.

How=20 high do you want to go? I think Tracy's been over 15k with = an NA=20

13B. I'd be willing to bet that a Velocity = with an NA=20 20B could get well

over 18k without a problem.

As I = recall my=20 analysis those many years ago; the cross over point on power for a=20 turbo-normalized 13B and a NA 20B is at about 13,500=92 msl. Above = that=20 altitude the torbo 13B will do better. Of course you can boost the = 13B to=20 more than 30=94 and get more power.

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