From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Ross Redrive se ex se
Date: Fri, 27 Nov 2020 07:09:15 +0800
References: <list-982349@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Message-Id: <CFE6AC86-CA9C-47CF-AD3A-112F886D7B60@gmail.com>

Why is that?
Tracy made the comment that even the 2.85 which I have is only really =
useful for props >than 74=E2=80=9D
Which I understood to be about the tip speed being to low and =
inefficient with  smaller diameter.
I dont want to spin my engine more than 7500 rpm.

What am I missing?

Steve


> On 27 Nov 2020, at 7:03 am, Ernest Christley echristley@att.net =
<flyrotary@lancaironline.net> wrote:
>=20
> At 70 inches, you would want to go the other way.  The C4 gearset was =
3.17, but the problem was the weak planetary gear carrier.  But, I just =
posted a link with a 6 planet carrier.
>=20
> On Thursday, November 26, 2020, 5:56:14 PM EST, Stephen Izett =
stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>=20
>=20
> On that note can I ask a gearbox question.
> I=E2=80=99ve always understood we only really had the choice of 2.17 =
and 2.85 :1 gear ratio options if using the Ford planetary gears.
>=20
> Looking at our Glasair and I imagine some other aircraft with prop =
diameters of around 70 inches we would prefer a ration around 2.6:1
> giving us I think a better prop rpm and tip speed.
>=20
> Are there other options?
>=20
> Steve Izett
>=20
>=20
>=20
> > On 27 Nov 2020, at 6:32 am, Ernest Christley echristley@att.net =
<flyrotary@lancaironline.net> wrote:
> >=20
> > Is that the 4 planet, C4 gear set?  If so, I've been made to =
understand that there aluminum body gets wallowed out by the planet =
gear's shaft.  I recently found that there is a performance shop selling =
a replacement unit with six planets.  I know nothing about them other =
than that.
> >=20
> > =
https://speedmaster79.com/Ford-C4-Transmission-Performance-6-Pinion-Planet=
ary-Gear-Set
> >=20
> > On Thursday, November 26, 2020, 3:16:01 PM EST, Le Roux Breytenbach =
breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:
> >=20
> >=20
> > Terry : Thanks Terry for the Ross Redrive the parcel arrived on =
Monday 23 Nov .
> > Neil if you want some dimensions on the hollow propellor shaft your =
welcome.
> > Regards
> >=20
> >=20
> > Sent from my iPhone
> > Le Roux Breytenbach--
> > Homepage:  http://www.flyrotary.com/
> > Archive and UnSub:  =
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>=20
>=20
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:  =
http://mail.lancaironline.net:81/lists/flyrotary/List.html