Return-Path: Received: from [65.54.169.78] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.2b3) with ESMTP id 84544 for flyrotary@lancaironline.net; Sat, 22 May 2004 14:39:09 -0400 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sat, 22 May 2004 11:27:30 -0700 Received: from 4.174.0.236 by bay3-dav48.bay3.hotmail.com with DAV; Sat, 22 May 2004 18:27:30 +0000 X-Originating-IP: [4.174.0.236] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Shertz Beam Date: Sat, 22 May 2004 14:27:28 -0400 MIME-Version: 1.0 X-Mailer: MSN Explorer 7.02.0011.2700 Content-Type: multipart/alternative; boundary="----=_NextPart_001_0001_01C44008.E92B46A0" Message-ID: X-OriginalArrivalTime: 22 May 2004 18:27:30.0565 (UTC) FILETIME=[713A0B50:01C4402A] ------=_NextPart_001_0001_01C44008.E92B46A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I have examined the "Shertz Beam" Motor mount on "the other" Mail List. Searched and did not find a comment on this list. Other than it is recomended by "The Other" list, is there anything wrong with it? I am looking for solid/semi solid engineering critique. I really dont wa= nt to talk about "feelings" or "preferance". Thans for your time. I prefer the straight stuff too so to get right to the core of it: 1. Shertz Beam - Which incantation do you mean? There is no single def= inition. I have seen at least 6 versions. In it's original incantation,= a SINGLE 6mm bolt in tension absorbed ALL of the torsion forces (prop to= rque and vibration loads). This was unacceptable. I have seen a few att= empts to fix this, some good some not. 2. The beam is NOT at the CG, contrary to claims otherwise. There are s= ignificant loads on the rear mount which is not even a part of the Shertz= beam design. It has been proposed that the rear of the engine be hung f= rom a central point off the engine front housing from an assembly made fr= om 2 rod ends. The other end is supposedly attached to a hard point near= the center of the firewall. On most aircraft, there IS NO HARD POINT at= this location. In addition, on an aerobatic plane where negative loads = can occur, the "hanging rod" in compression is 'less than ideal'. =20 3. This mount more or less assumes that the rad is going to be mounted u= nder the engine. This rad location and the Shertz beam makes more sense = on a composite canard design but on a tractor, the mount ends up taking u= p space in the wrong places. The most popular and successful cooling sch= eme so far use two heat exchangers in a location that interfears with thi= s mount. It would also not work with what I plan to do on my -8 with a = single rad. Tracy Crook ------=_NextPart_001_0001_01C44008.E92B46A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

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I have examined the "Shertz Beam" Motor mount on "t= he other" Mail List.

Searched and did not find a comment on this l= ist.

Other than it is recomended by "The Other" list, is there any= thing wrong
with it?

I am looking for solid/semi solid engineer= ing critique. I really dont want
to talk about "feelings" or "pr= eferance".

Thans for your time.

I prefer the straig= ht stuff too so to get right to the core of it:

1. Shertz Be= am - Which incantation do you mean? There is no single defini= tion. I have seen at least 6 versions. In it's original incan= tation, a SINGLE 6mm bolt in tension absorbed ALL of the torsion forces (= prop torque and vibration loads). This was unacceptable. I ha= ve seen a few attempts to fix this, some good some not.

2. T= he beam is NOT at the CG, contrary to claims otherwise. There are s= ignificant loads on the rear mount which is not even a part of the Shertz= beam design. It has been proposed that the rear of the e= ngine be hung from a central point off the engine front housing from an a= ssembly made from 2 rod ends. The other end is supposedly attached = to a hard point near the center of the firewall. On most aircraft, = there IS NO HARD POINT at this location. In addition, on an aerobat= ic plane where negative loads can occur, the "hanging rod" in compression= is 'less than ideal'.

3. This mount more or= less assumes that the rad is going to be mounted under the engine. = This rad location and the Shertz beam makes more sense on= a composite canard design but on a tractor, the mount ends up taking up = space in the wrong places. The most popular and successful cooling = scheme so far use two heat exchangers in a location that interfears with = this mount. It would also not work with what I plan to do on my -8= with a single rad.

Tracy Crook

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