X-Virus-Scanned: clean according to Sophos on Logan.com From: Received: from mail-qt0-f178.google.com ([209.85.216.178] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9599909 for flyrotary@lancaironline.net; Thu, 23 Mar 2017 06:59:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.216.178; envelope-from=rwstracy@gmail.com Received: by mail-qt0-f178.google.com with SMTP id r45so171603632qte.3 for ; Thu, 23 Mar 2017 03:59:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:mime-version:to:from:subject:date:importance:in-reply-to :references; bh=1DZDWFWSZJrPjYkPBtd+gNcpQ8F5Ml6Ia4RYgI1iZgE=; b=izavqszJmXmU/bNW/qUiK21gexrGVsrrNcLA3dUimcfhSkjpYxezQZPh+YYrE1wJYB SS3iPRWKK5KWZWBezotIntnPHnDwtx6uzlw5d+tBAmQztukzczyzK9eUaMjOgOZEQZxT RHLeuEbu0pzn7OML+uFlYBzLyTkaqs8H0dIVAuQ2V0uYBHhwfvVqddu7LMDN7rkGF3Xr DIHE8f5kFLxiMY0Y+AaeMkyZfBBoODka5BQk7aMf0J5S7tuDkZIG4iiLFRJialvn1B+o d8efcnVAdIQOTlQ9Ow3EWMzV3Gftaodw2Zdgo9ZrbBIpewq55JqJhG6/AJ6MNfBTHGvv lP3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:mime-version:to:from:subject:date :importance:in-reply-to:references; bh=1DZDWFWSZJrPjYkPBtd+gNcpQ8F5Ml6Ia4RYgI1iZgE=; b=bIWnWjwRXFOUxQkCC0uQyK3b0tXC3E02ZnhpfN6goqOrAHqV7Mb44sax0yH2UwZ7YT Giw+iqJbdtInsXBSpLJSYPzNJJq8Wrwz/y30tF9ZDhbX4c19cUEYJrplRnxwWxgJtEiR tM1sI6o3R6WfrQOsRO/xPkKYbCJIGcG7neSKrPKP7HuP7iiW/skBs3+pd8gCrP7Kgei0 YRYAbSeSi8eEmlftL0+AcHF53YocZH5V4PfxZ1EdAcAfHpnjUwQoZwvxau2ktcpquDKW qgc6hbC1+MbT8MPSO5cSZuArqjQY/Klndz74MTm9cexOzOFA2MASbKmInSBfnimwh037 AkFw== X-Gm-Message-State: AFeK/H2gRu65DWKOjkcXftN35vkJpD8+PL/nsCeGrrSBNi/n5DSzpLJdB8NjQtRIxNC1LA== X-Received: by 10.237.50.97 with SMTP id y88mr1731415qtd.104.1490266736532; Thu, 23 Mar 2017 03:58:56 -0700 (PDT) Return-Path: Received: from ?IPv6:::ffff:192.168.254.5? (h224.112.131.174.dynamic.ip.windstream.net. [174.131.112.224]) by smtp.gmail.com with ESMTPSA id f126sm2965237qkc.47.2017.03.23.03.58.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Mar 2017 03:58:55 -0700 (PDT) Message-ID: <58d3aa6f.846a370a.b0f89.0220@mx.google.com> MIME-Version: 1.0 To: Lehanover Subject: RE: [FlyRotary] Re: redrive options Date: Thu, 23 Mar 2017 06:58:53 -0400 Importance: normal X-Priority: 3 In-Reply-To: References: Content-Type: multipart/alternative; boundary="_01F7A85D-31C1-41A4-B938-CFD93BBD746A_" --_01F7A85D-31C1-41A4-B938-CFD93BBD746A_ Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 idl= e 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 an= d on shut down where it rattles for 1 or two revolutions. Not a problem si= nce there is no more energy being fed into the system and it is quickly dam= ped by the prop. I expected to have different characteristics on the RD-2 drive which has n= o damper, just a tight spline coupling to the flywheel. There was no notic= eable 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 remo= ved. The weight turned out to be very close to the RD-1 with flexplate se= tup since the damper weight was not there anymore. The no damper RD-2 is a= t 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 pr= op balance rather than engine/flywheel weight & balance. =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 usi= ng 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 2= 0 years since I started making drives anyway. If anyone wants to experimen= ting with building drives I=E2=80=99d recommend a no-damper setup. It grea= tly simplified the design and looks to have no down-side other than the pro= p 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 =C2=A0Drummond built bridg= e ported 12-A of about 244 HP.=C2=A0=C2=A0 =C2=A0 =C2=A0The builder with the RX-7 gearbox reduction system was Mr. Graham=C2= =A0 in=C2=A0a Varyeasy =C2=A0I believe.=20 =C2=A0 My=C2=A0racer 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.=C2=A0 The flex plate is just to ca= rry the ring gear for starting and sees no other loads except for low RPM s= haking. =C2=A0 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 usua= l Rupp-Rupp-Rupp idle sound. =C2=A0 I set the idle up to 2,200 RPM because clutch management was not the driver= s strong suit. =C2=A0 Also this got him to spend less time in the rock crushing RPM/sound from th= e transmission as the car moved away from stopped. =C2=A0 Like a really big blender full of aircraft bolts. This around 1600 RPM. Low= er with light rotors. =C2=A0 Best power is at 9,400 RPM. Shifting at 9,600 RPM =C2=A0 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 driv= e Tracy's torque absorber or similar. =C2=A0 This to further damp the torque pulses and move them up the RPM band away f= rom idle and ground operation RPM. Start with a steel flywheel or a new fle= x 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.=C2=A0 There are straight = cut gears in the quick change differential as well. =C2=A0 (Move the throttle off of idle slowly. The=C2=A0amount of power in play whi= le passing through the problem RPM determines the amount of stress applied)= . =C2=A0 Lynn E. Hanover =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0 --_01F7A85D-31C1-41A4-B938-CFD93BBD746A_ Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8"

Thanks Lynn, good info as usual

<= p class=3DMsoNormal>.=C2=A0

Here=E2=80=99s my obse= rvations on drive train resonance with street ported 13B (original or Renes= is) configured with RWS drives (B & C) and wood props.=C2=A0 The resona= nt frequency of the full drive train is around 800 rpm.=C2=A0 This passes s= o quickly on startup that I don=E2=80=99t notice it at all.=C2=A0 My idle i= s around 1600 RPM, well above the =E2=80=98rock crushing=E2=80=99 point.=C2= =A0=C2=A0 I notice the resonance only when experimenting with lower idle sp= eeds and on shut down where it rattles for 1 or two revolutions.=C2=A0 Not = a problem since there is no more energy being fed into the system and it is= quickly damped by the prop.

 

<= p class=3DMsoNormal>I expected to have =C2=A0different characteristics on t= he RD-2 drive which has no damper, just a tight spline coupling to the flyw= heel.=C2=A0 There was no noticeable change at all.=C2=A0 Apparently the res= onant point and damping are mainly controlled by the gear lash and total fl= ywheel and prop weight. =C2=A0On the RD-2 =C2=A0I used an aluminum racing f= lywheel with the steel clutch wear plate removed.=C2=A0 The weight turned o= ut to be very close to the RD-1 with =C2=A0flexplate setup since the damper= weight was not there anymore.=C2=A0 The no damper RD-2 is at least if not = better in smoothness compared to the RD-1.=C2=A0=C2=A0 Whenever I=E2=80=99v= e felt any significant roughness, it=E2=80=99s always been due to prop bala= nce rather than engine/flywheel weight & balance.=C2=A0 =C2=A0=C2=A0

 

I have abou= t 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.=C2=A0 The RD-2 is not rated for use with metal props because of this.= =C2=A0 I don=E2=80=99t know of anyone wanting to use a metal prop in the 20= years since I started making drives anyway.=C2=A0 If anyone wants to exper= imenting with building drives I=E2=80=99d recommend a no-damper setup.=C2= =A0 It greatly simplified the design and looks to have no down-side other t= han the prop limitation.=C2=A0 I know the no-damper sounds like blasphemy b= ut 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: Leh= anover
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 2= 44 HP.  

 

    

 

= --_01F7A85D-31C1-41A4-B938-CFD93BBD746A_--