X-Virus-Scanned: clean according to Sophos on Logan.com From: "GEORGE PUTNAM" Received: from pv38p43im-ztdg05061201.me.com ([17.133.183.25] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9601351 for flyrotary@lancaironline.net; Thu, 23 Mar 2017 13:34:29 -0400 Received-SPF: pass receiver=logan.com; client-ip=17.133.183.25; envelope-from=georgeputnam@me.com Received: from process-dkim-sign-daemon.pv38p43im-ztdg05061201.me.com by pv38p43im-ztdg05061201.me.com (Oracle Communications Messaging Server 7.0.5.38.0 64bit (built Feb 26 2016)) id <0ONA00F003C0ZQ00@pv38p43im-ztdg05061201.me.com> for flyrotary@lancaironline.net; Thu, 23 Mar 2017 17:34:04 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=me.com; s=4d515a; t=1490290444; bh=SrIN2jEgWURFazsGmOwJ8ZNpuGf+tpLDsj8dBz+6B34=; h=From:Content-type:MIME-version:Subject:Date:To:Message-id; b=pY+DzS5sToF7iv3+neVDNpKcY5xuZ6GNzhweX77ik8LlfcVX48e6YT+Y+RbJNGO5t s2WeR9iKQF1sGKwjAPm/CSROKyh5Mpo735vEzd6pN8JqQp1OApzCa+x7dT9YVKTocF dwewx8A28vgc5IN1P8hSX5fvDiufan1L7WFT6O4YbTKAeHQYnFwPHbDCsl/OZpGhVp +vJ1i4kjRio4/AyBMh6LKXX/9I8eRKPQ0X4xTj33p8hOF6LGKsib65C9bh5KGClsct y1ttmJNzgCvrtngRCu2rmXxQ5WysnmlUTf8WDFhfQucUlpqDjZKO5M6/SyUtTMHZbt lWHRnDwAQ2rcw== Received: from icloud.com ([127.0.0.1]) by pv38p43im-ztdg05061201.me.com (Oracle Communications Messaging Server 7.0.5.38.0 64bit (built Feb 26 2016)) with ESMTPSA id <0ONA006NW3GPYY00@pv38p43im-ztdg05061201.me.com> for flyrotary@lancaironline.net; Thu, 23 Mar 2017 17:34:03 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-03-23_15:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 clxscore=1034 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1701120000 definitions=main-1703230152 Content-type: multipart/alternative; boundary="Apple-Mail=_F4607350-2988-42CC-AF3E-89654E6F0976" MIME-version: 1.0 (Mac OS X Mail 10.2 \(3259\)) Subject: Re: [FlyRotary] Re: redrive options Date: Thu, 23 Mar 2017 09:34:01 -0800 References: To: Rotary motors in aircraft In-reply-to: Message-id: <5730771D-9057-4F45-B37F-CA4CD22F21D2@me.com> X-Mailer: Apple Mail (2.3259) --Apple-Mail=_F4607350-2988-42CC-AF3E-89654E6F0976 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Here=E2=80=99s hoping that you reach that magical point of boredom = someday soon!! George > On Mar 23, 2017, at 2:58 AM, rwstracy = wrote: >=20 > Thanks Lynn, good info as usual > . =20 > Here=E2=80=99s my observations on drive train resonance with street = ported 13B (original or Renesis) configured with RWS drives (B & C) and = wood props. The resonant frequency of the full drive train is around = 800 rpm. This passes so quickly on startup that I don=E2=80=99t notice = it at all. My idle is around 1600 RPM, well above the =E2=80=98rock = crushing=E2=80=99 point. I notice the resonance only when = experimenting with lower idle speeds and on shut down where it rattles = for 1 or two revolutions. Not a problem since there is no more energy = being fed into the system and it is quickly damped by the prop. > =20 > I expected to have different characteristics on the RD-2 drive which = has no damper, just a tight spline coupling to the flywheel. There was = no noticeable change at all. Apparently the resonant point and damping = are mainly controlled by the gear lash and total flywheel and prop = weight. On the RD-2 I used an aluminum racing flywheel with the steel = clutch wear plate removed. The weight turned out to be very close to = the RD-1 with flexplate setup since the damper weight was not there = anymore. The no damper RD-2 is at least if not better in smoothness = compared to the RD-1. Whenever I=E2=80=99ve felt any significant = roughness, it=E2=80=99s always been due to prop balance rather than = engine/flywheel weight & balance. =20 > =20 > I have about 80 hours on the RD-2C now so I=E2=80=99ve come to believe = that the damper is not a critical need on the aircraft configuration = unless using a metal prop. The RD-2 is not rated for use with metal = props because of this. I don=E2=80=99t know of anyone wanting to use a = metal prop in the 20 years since I started making drives anyway. If = anyone wants to experimenting with building drives I=E2=80=99d recommend = a no-damper setup. It greatly simplified the design and looks to have = no down-side other than the prop limitation. I know the no-damper = sounds like blasphemy but If I ever get bored and have to make drives = again that=E2=80=99s the way I=E2=80=99d go. > =20 > Tracy > =20 > Sent from Mail for = Windows 10 > =20 > From: Lehanover > Sent: Wednesday, March 22, 2017 8:33 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: redrive options > =20 > Allow me to describe the racer setup for a Daryl Drummond built = bridge ported 12-A of about 244 HP. =20 > =20 > The builder with the RX-7 gearbox reduction system was Mr. Graham in = a Varyeasy > I believe.=20 > =20 > My racer has a steel button flywheel just enough diameter to mount the = 5 1/4" dual disc clutch pack. This mounts over a stock flex plate with = the ring gear TIG welded to the flex plate. The flex plate is just to = carry the ring gear for starting and sees no other loads except for low = RPM shaking. > =20 > The Rotors are not lightened. The crank is not lightened. The gears in = the trans are straight cut. The engine uses a Weber 48IDF carb and has = the usual Rupp-Rupp-Rupp idle sound. > =20 > I set the idle up to 2,200 RPM because clutch management was not the = drivers strong suit. > =20 > Also this got him to spend less time in the rock crushing RPM/sound = from the transmission > as the car moved away from stopped. > =20 > Like a really big blender full of aircraft bolts. This around 1600 = RPM. Lower with light rotors. > =20 > Best power is at 9,400 RPM. Shifting at 9,600 RPM > =20 > If you have seen the 45 pound stock flywheel you would know that there = is a problem of some sort. I suggest using a steel aftermarket flywheel = to drive Tracy's torque absorber or similar. > =20 > This to further damp the torque pulses and move them up the RPM band = away from idle and ground operation RPM. Start with a steel flywheel or = a new flex plate and check it for cracks > every preflight. The racer still has the original used flex plate, = with no cracks. No driveline damage in 9 years of racing. There are = straight cut gears in the quick change differential as well. > =20 > (Move the throttle off of idle slowly. The amount of power in play = while passing through the problem RPM determines the amount of stress = applied). > =20 > Lynn E. Hanover --Apple-Mail=_F4607350-2988-42CC-AF3E-89654E6F0976 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 Here=E2=80=99s hoping that you reach that magical point of = boredom someday soon!!
George
On = Mar 23, 2017, at 2:58 AM, rwstracy <flyrotary@lancaironline.net> wrote:

Thanks Lynn, good info as = usual
.  
Here=E2=80=99s my observations on drive train resonance with = street ported 13B (original or Renesis) configured with RWS drives (B = & C) and wood props.  The resonant frequency of the full drive = train is around 800 rpm.  This passes so quickly on startup that I = don=E2=80=99t notice it at all.  My idle is around 1600 RPM, well = above the =E2=80=98rock crushing=E2=80=99 point.   I notice = the resonance only when experimenting with lower idle speeds and on shut = down where it rattles for 1 or two revolutions.  Not a problem = since there is no more energy being fed into the system and it is = quickly damped by the prop.
 
I = expected to have  different characteristics on the RD-2 drive which = has no damper, just a tight spline coupling to the flywheel.  There = was no noticeable change at all.  Apparently the resonant point and = damping are mainly controlled by the gear lash and total flywheel and = prop weight.  On the RD-2  I used an aluminum racing flywheel = with the steel clutch wear plate removed.  The weight turned out to = be very close to the RD-1 with  flexplate setup since the damper = weight was not there anymore.  The no damper RD-2 is at least if = not better in smoothness compared to the RD-1.   Whenever = I=E2=80=99ve felt any significant roughness, it=E2=80=99s always been = due to prop balance rather than engine/flywheel weight & = balance.    
 
I have = about 80 hours on the RD-2C now so I=E2=80=99ve come to believe that the = damper is not a critical need on the aircraft configuration unless using = a metal prop.  The RD-2 is not rated for use with metal props = because of this.  I don=E2=80=99t know of anyone wanting to use a = metal prop in the 20 years since I started making drives anyway.  = If anyone wants to experimenting with building drives I=E2=80=99d = recommend a no-damper setup.  It greatly simplified the design and = looks to have no down-side other than the prop limitation.  I know = the no-damper sounds like blasphemy but If I ever get bored and have to = make drives again that=E2=80=99s the way I=E2=80=99d go.
 
Tracy
 
Sent from Mail for Windows 10
 
From: Lehanover
Sent: Wednesday, March 22, = 2017 8:33 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: redrive = options
 
Allow me to describe the racer setup for a Daryl =  Drummond built bridge ported 12-A of about 244 HP.  
 
 The builder with the RX-7 gearbox = reduction system was Mr. Graham  in a Varyeasy
 I believe. 
 
My racer has a steel button flywheel just = enough diameter to mount the 5 1/4" dual disc clutch pack. This mounts = over a stock flex plate with the ring gear TIG welded to the flex = plate.  The flex plate is just to carry the ring gear for starting = and sees no other loads except for low RPM shaking.
 
The Rotors are not lightened. The crank is not = lightened. The gears in the trans are straight cut. The engine uses a = Weber 48IDF carb and has the usual Rupp-Rupp-Rupp idle sound.
 
I set the idle up to 2,200 RPM because clutch = management was not the drivers strong suit.
 
Also this got him to spend less time in the rock = crushing RPM/sound from the transmission
as the car moved away from stopped.
 
Like a really big blender full of aircraft = bolts. This around 1600 RPM. Lower with light rotors.
 
Best power is at 9,400 RPM. Shifting at 9,600 = RPM
 
If you have seen the 45 pound stock flywheel you = would know that there is a problem of some sort. I suggest using a steel = aftermarket flywheel to drive Tracy's torque absorber or similar.
 
This to further damp the torque pulses and move = them up the RPM band away from idle and ground operation RPM. Start with = a steel flywheel or a new flex plate and check it for cracks
every preflight. The racer still has the = original used flex plate, with no cracks. No driveline damage in 9 years = of racing.  There are straight cut gears in the quick change = differential as well.
 
(Move the throttle off of = idle slowly. The amount of power in play while passing through the = problem RPM determines the amount of stress applied).
 
Lynn E. = Hanover

= --Apple-Mail=_F4607350-2988-42CC-AF3E-89654E6F0976--