X-CGP-ClamAV-Result: CLEAN X-VirusScanner: Niversoft's CGPClamav Helper v1.23.0 (ClamAV engine v0.103.0) X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "Charlie England ceengland7@gmail.com" Received: from mail-io1-f48.google.com ([209.85.166.48] verified) by logan.com (CommuniGate Pro SMTP 6.3.5) with ESMTPS id 363843 for flyrotary@lancaironline.net; Fri, 15 Oct 2021 09:16:19 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.166.48; envelope-from=ceengland7@gmail.com Received: by mail-io1-f48.google.com with SMTP id 188so7625623iou.12 for ; Fri, 15 Oct 2021 06:16:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=2MRQtMZctR5BIANcCMIj/vZq9m6A38FfUqS29+RWpnw=; b=pnGNuNSGpOPfosFJrjSnkfpG6HSN/VsY1OJZVJpjqmtjykaImS6vlm1IzsCK/gMYEb ELo9WbuRT2ThFb46Ge3/xGPWRcZsnAh9ka0O5fFRp0hJPKaUB7LfHiPY1UIoPw7+6yge s2wJIWIqGU1evhEf//7QfWUA/8Xb8QO/yG6gJw7cjpQraoNbNY/8MNkdh+VqdaGevvlp v9G36YKD0UB45sSMwHH7YyO2TqM7lHUBTq7zpKk0Nv5gnjxihK9r+HfEdr9LOwV/3bE/ 2P7LUhYMowWNPjlydhxxxr077x7emcubllZzcjSEeia4F5FKnWW5OZkUgkgEoo2zTOBn akrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=2MRQtMZctR5BIANcCMIj/vZq9m6A38FfUqS29+RWpnw=; b=LxEAB4AlhTQEUxknWqGK3XNtGop4QZlPllayp1WsE81h60izn31Pe9scqM3f71vMWB /IJoXvr8za5f6WQaZ5F/3bo7bZgjLlIlN5okaKTRkATxqP8669iA2kzOdI3RWv9eeKFS BREK6C3XYRCDhcpBnmenGeJ/RWLWS+3JN9q0phGyWDDD59k2dRFxZQWl/c3FbLhukLag mgh8QY7nYw4JkD+Od2Tvu8YnQ/xOQMepP7SPngMomEP4Aj3tgQ+uJl5SXEPwmg3xN7R1 2VIEiS11ERN/Jg/liIwhPaJ8/cuBfcADWVkOSejzOaZxmAz6QHQUJQ+Uakz5Jlfuvy0P aTOA== X-Gm-Message-State: AOAM533x9K/z2MiGgMHnCBBrKy9JSgpLX9Y1w8ywXyksEkOYSPKKP4oT m0N3eUEkOwP6vgkJnDgT8YTqtmnu/Qqri2g0RWttfIYa X-Google-Smtp-Source: ABdhPJx2He83c1H6K0KyU5sTMBdMN2Re+LrSjDs0hlliOoa47MbnmFgUrJLprOZga9gS6gDGZFOdbTf/ZbdDgcOrSd4= X-Received: by 2002:a02:2b08:: with SMTP id h8mr8381534jaa.137.1634303761426; Fri, 15 Oct 2021 06:16:01 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Fri, 15 Oct 2021 08:15:51 -0500 Message-ID: Subject: Re: [FlyRotary] Re: Marcotte 2.4:1 vs RWS RD-1C 2.85:1 To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000027abd905ce63ff6f" --00000000000027abd905ce63ff6f Content-Type: text/plain; charset="UTF-8" I've run an IVO on a Lyc, for a very short time. I won't do it again. The ones I've seen (about 15 years ago) did not have drive lugs for the blades. Early versions had smooth faced hubs; later ones had knurled faces on the hub plates in an attempt to keep the blades from moving in the hub. Nothing was successful, and he finally quit selling them for Lycs. Sad thing is, they'd probably have worked ok if he'd designed them with drive lugs like all the Lyc props use. They seem to work ok on small 2stroke engines in ultralite-like a/c. The picture *might* get better on a rotary with its much higher frequency of impulses and no torque reversals like the Lyc. The other issue is the aero 'wall' at around 150-160 mph because the IVO blades don't have enough twist for high speed efficiency. On the ratio issue, what HP is the airframe designed for, and how much fuel will it carry, and how much can you afford to feed the engine? With a 2.85:1 drive, a 300+ HP 20B is going to go through quite a bit of fuel. Even if you back down to 200 HP at cruise, that will be at least 16-17 gallons per hour of fuel consumption. On the flip side, how big a prop can you swing on your airframe? If you use the 2.85, limit engine rpm to the lower figure, and can swing a large diameter prop (80" range), you'll get a huge boost in takeoff/climb performance with little to no top speed penalty, even with a fixed pitch prop. FWIW, Charlie On Thu, Oct 14, 2021 at 11:19 PM Terry Adams terrywadams@sbcglobal.net < flyrotary@lancaironline.net> wrote: > Les, > The IVO prop may be the weak link. Quite some time ago there was > information posted concerning the prop blades. I am not in a position to > say, but you may want to do some additional research. > > Terry > > On 10/14/2021 6:38 PM, Les C lesphoto@hotmail.com wrote: > > I have the good fortune to have both of these redrives in my garage as I > have gathered parts for my BD-4 project. I took advantage of timely offers > and can only use one of them. My motor is a 20b built by Bob Darrah. I > like the idea of keeping the RPM's down with the Marcotte drive to 6500, > but the RWS drive would allow me to develop additional power at 7500. I > have an IVO prop that I will be using with inflight "controllable" pitch. > > So I throw it out there to you. Which PRSU do I keep? > > Les Criscillo > Nurse, Pilot, Brewmaster, Maker > https://eaabuilderslog.org/?blproject&proj=7XSZ512C2 > > > -- > Communication ink and paper free > > --00000000000027abd905ce63ff6f Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I&#= 39;ve run an IVO on a Lyc, for a very short time. I won't do it again. = The ones I've seen (about 15 years ago) did not have drive lugs for the= blades. Early versions had smooth faced hubs; later ones had knurled faces= on the hub plates in an attempt to keep the blades from moving in the hub.= Nothing was successful, and he finally quit selling them for Lycs. Sad thi= ng is, they'd probably have worked ok if he'd designed them with dr= ive lugs like all the Lyc props use. They seem to work ok on small 2stroke = engines in ultralite-like a/c. The picture *might* get better on a rotary w= ith its much higher frequency of impulses and no torque reversals like the = Lyc. The other issue is the aero 'wall' at around 150-160 mph becau= se the IVO blades don't have enough twist for high speed efficiency.

On the ratio issue, what HP= is the airframe designed for, and how much fuel will it carry, and how muc= h can you afford to feed the engine? With a 2.85:1 drive, a 300+ HP 20B is = going to go through quite a bit of fuel. Even if you back down to 200 HP at= cruise, that will be at least 16-17 gallons per hour of fuel consumption.<= /div>

On the flip side, how big= a prop can you swing on your airframe? If you use the 2.85, limit engine r= pm to the lower figure, and can swing a=C2=A0 large=C2=A0diameter prop (80&= quot; range), you'll get a huge boost in takeoff/climb performance with= little to no top speed penalty, even with a fixed pitch prop.

FWIW,

Charlie

On Thu, Oct 14, 2021 at 11:19 PM Terry Ad= ams terrywadams@sbcglobal.net<= /a> <flyrotary@lancaironl= ine.net> wrote:
=20 =20 =20
Les,
The IVO prop may be the weak link.=C2=A0 Quite some time ago there wa= s information posted concerning the prop blades.=C2=A0 I am not in a position to say, but you may want to do some additional research.

Terry

On 10/14/2021 6:38 PM, Les C lesphoto@ho= tmail.com wrote:
=20 =20
I have the good fortune to have both of these redrives in my garage as I have gathered parts for my BD-4 project.=C2=A0 I took advantage of timely offers and can only use one of them.=C2=A0 My motor is a 20b built by Bob Darrah.=C2=A0 I like the idea of keepin= g the RPM's down with the Marcotte drive to 6500, but the RWS drive would allow me to develop additional power at 7500.=C2=A0 I have an IVO prop that I will be using with inflight "controllable" pitch.=C2=A0

So I throw it out there to you.=C2=A0 Which PRSU do I keep?

Les Criscillo
Nurse, Pilot, Brewmaster, Maker
https://eaabuilderslog.org/?blproject&proj= =3D7XSZ512C2

--=20
Communication ink and paper free
--00000000000027abd905ce63ff6f--