X-Virus-Scanned: clean according to Sophos on Logan.com From: "William Jepson" Received: from mail-vk0-f51.google.com ([209.85.213.51] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9594132 for flyrotary@lancaironline.net; Tue, 21 Mar 2017 16:52:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.213.51; envelope-from=wrjjrs@gmail.com Received: by mail-vk0-f51.google.com with SMTP id j64so92901875vkg.3 for ; Tue, 21 Mar 2017 13:52:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=eJkJ+K9c3II2gREde/WJ/ciXfePMHrPuOmp2lJglo+c=; b=cuhtBSRmt3/OfvMxEYfgEiXRI91JoPQqQBjN1iALvLDVAZvb3f3o4r9eo9+zpft8Ex 6zs+2vUIuZthJfHj7y/vlibRFXjkHWK4S50JosJ0hu4dI2k3cMmW5fXKTWIu0lLCQH90 25z4MtuExKl+VNqiMN+D8YHMX16AXzE4aGrFX7Bk/H0PqAXFW5TfCtnhguhI3N0OD/gD LjQs/ygYwwmZ0hKsQR7EoedfLpOs5vlKfbDuhg4WyftdHhg6hrGe15PlkSchciZtesuf EPfSXhCNA7NYhl95nully5RfYyfskJTdoOgfjCD8ueO6znWEx62JjfLhBqwcDU7RxPMh 1BvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=eJkJ+K9c3II2gREde/WJ/ciXfePMHrPuOmp2lJglo+c=; b=eaN+883/Jr6KyfRSkgKxMsLsSqU9JIxyu1s8rPjpLwbCkwUFYA7H2Zl5FxsyZaw9gN P+rVnc0nH+v6wDMFp122qRzcPyjyY5Ox44Z7g2kMwFMgd0chKx9ZHn6J5bxb6h3dC6jW OP5Sgg0ceSoa6l+QmpETN/HXcVVio5S4ZrMzby47WkZpnV5aJqZh7FYDkkRKq6yDIfx7 KYYcdluqV3JN22IQ6OToW6OcADLMxtUZDICahxNMmtv0ZH3uc4qhHPVijtE+d2CGmoCJ 4opA1YPOUyAjAJEvC1+yzq+rKpuJNEp5P3eSlZoZXpWehDEPKOOWDMdfFj54Gx8Tkh0V DXwA== X-Gm-Message-State: AFeK/H25ioZ8gnAFNUKYYfpoXaRfN+3+epuWAT2R/p+UgJGmpjBwSEJ0JVeRiYO/TyeYmtwb8prc0ZvMeYXx/Q== X-Received: by 10.31.10.133 with SMTP id 127mr6962463vkk.5.1490129506517; Tue, 21 Mar 2017 13:51:46 -0700 (PDT) MIME-Version: 1.0 Received: by 10.31.44.23 with HTTP; Tue, 21 Mar 2017 13:51:46 -0700 (PDT) In-Reply-To: References: Date: Tue, 21 Mar 2017 13:51:46 -0700 Message-ID: Subject: Re: [FlyRotary] Re: redrive options To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=001a1144142ce7db91054b43cf14 --001a1144142ce7db91054b43cf14 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Charlie, In terms of simple vibration caused by out of balance you are correct. It terms of torsional vibration though the rotary is a tough customer. Part of the problem is that the e-shaft on the rotary is so stiff. I have been working with Steve Beckham from the original PowerSport. Steve told me about how a 200 HP rotary just blew up the input shaft on a dyno that was regularly used to test 600+ HP V8 piston engines. This is the torque pulses of the engine, not out-of-balance. It is likely that in that case the rotary hit a amplifying couple or harmonic frequency with the dyno causing the failure. That said Steve and Everett Hatch did a LOT of work to be sure their "stiff" model reduction drive placed all the frequencies above the normal operating range. If you hit one of those frequencies with one of the rubber couplings or the bushing-around-bolt dampers it will fail period. Most of those systems try to push the first order frequency below the operating range. That is why you will often hear the engine shut down rattle with a planetary. Typically the energy in the system is low enough to pass through that RPM without damage. Usually. But if not planned for those pulses can be a disaster. Bill Jepson On Tue, Mar 21, 2017 at 10:40 AM, cozygirrrl wrote: > > Rotary torque pulses can be very destructive before buying anything > specifically=E2=80=8B mention the rotary. If they know anything they will= be > worried. > > Bill Jepson > > > Somebody please correct me if I am wrong but I have understood the > opposite, the rotary engine does not have the 4 bangs per prop revolution > of a traditional 4 cylinder aircraft engine which shows as a spiky positi= ve > and negative graph when plotted. > The output of the rotary is always positive torque in nature and > overlapping sinusoidal due to the two rotors when the output wave forms a= re > plotted, hence the smoothness of the rotary. When peak output is plotted = it > shows an always positive gentle wave. > > Chrissi > CG Products > www.CozyGirrrl.com > > > > -----Original Message----- > From: William Jepson > To: Rotary motors in aircraft > Sent: Mon, Mar 20, 2017 7:02 pm > Subject: [FlyRotary] Re: redrive options > > Rotary torque pulses can be very destructive before buying anything > specifically=E2=80=8B mention the rotary. If they know anything they will= be > worried. > > Bill Jepson > > On Mar 20, 2017 3:48 PM, "drhyed" wrote: > > I had brief conversation with them last fall and they designed the gearbo= x > with the intention of offering higher horsepower options: > > "We do have plans for a higher horsepower engine. When we designed our > gearbox we intended to do engines to about 225 hp from the start. > > Our intent is to do a 155 hp normally aspirated 2 liter and a 200 hp turb= o > version" > > I did not mention a rotary engine specifically though. > > > Jay > > On Mar 20, 2017, at 5:31 PM, Charlie England > wrote: > > These guys have been advertising on ebay for a while. I have no idea abou= t > whether they are legit, or whether the drive is suitable for a rotary. Th= e > web page claims 'good up to 225HP', but their target installations are > closer to half that, so.... > > http://www.aeromomentum.com/partslist.html > > Charlie > > --001a1144142ce7db91054b43cf14 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Charlie,
In terms of simple vibration caused by out of= balance you are correct. It terms of torsional vibration though the rotary= is a tough customer. Part of the problem is that the e-shaft on the rotary= is so stiff. I have been working with Steve Beckham from the original Powe= rSport. Steve told me about how a 200 HP rotary just blew up the input shaf= t on a dyno that was regularly used to test 600+ HP V8 piston engines. This= is the torque pulses of the engine, not out-of-balance. It is likely that = in that case the rotary hit a amplifying couple or harmonic frequency with = the dyno causing the failure. That said Steve and Everett Hatch did a LOT o= f work to be sure their "stiff" model reduction drive placed all = the frequencies above the normal operating range. If you hit one of those f= requencies with one of the rubber couplings or the bushing-around-bolt damp= ers it will fail period. Most of those systems try to push the first order = frequency below the operating range. That is why you will often hear the en= gine shut down rattle with a planetary. Typically the energy in the system = is low enough to pass through that RPM without damage. Usually. But if not = planned for those pulses can be a disaster.
Bill Jepson

On Tue, Mar 21,= 2017 at 10:40 AM, cozygirrrl <flyrotary@lancaironline.net&g= t; wrote:

Rotary torque = pulses can be very destructive before buying anything specifically=E2=80=8B= mention the rotary. If they know anything they will be worried.

Bill Jepson

Somebody please correct me if I am wrong but = I have understood the opposite, the rotary engine does not have the 4 bangs= per prop revolution of a traditional 4 cylinder aircraft engine which show= s as a spiky positive and negative graph when plotted.
The output of the rotary is always positive torque in nature and overlappin= g sinusoidal due to the two rotors when the output wave forms are plotted, = hence the smoothness of the rotary. When peak output is plotted it shows an= always positive gentle wave.

Chrissi =20
CG Products=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0
=C2=A0


-----= Original Message-----
From: William Jepson <flyrotary@lancaironline.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, Mar 20, 2017 7:02 pm
Subject: [FlyRotary] Re: redrive options

Rotary torque pulses can be very destructive before buyin= g anything specifically=E2=80=8B mention the rotary. If they know anything = they will be worried.

Bill Jepson

On Mar 20, 2017 3:4= 8 PM, "drhyed" <flyrotary@lancaironline.net<= /a>> wrote:
I had brief conversation with them last fall and they designed the gea= rbox with the intention of offering higher horsepower options:

"We do have = plans for a higher horsepower engine.=C2=A0 When we designed our gearbox we= intended to do engines to about 225 hp from the start.

Our intent is to do a 155 hp normally aspirated 2 liter and a 200 hp turbo = version"

I did not mention a rotary engine specifically though.


Jay
These guys have been advertising on ebay for a while. I ha= ve no idea about whether they are legit, or whether the drive is suitable f= or a rotary. The web page claims 'good up to 225HP', but their targ= et installations are closer to half that, so....


Charlie


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