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 13:59:14 +0800
References: <list-982638@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-982638@logan.com>
Message-Id: <3CD6131C-C7C1-4854-AC0F-C1542034D67B@gmail.com>

Thanks Charlie.
So are there any other ratio=E2=80=99s in the ford sets that can fit our =
reprove housings?

Steve

> On 27 Nov 2020, at 9:08 am, Charlie England ceengland7@gmail.com =
<flyrotary@lancaironline.net> wrote:
>=20
> I'd agree with you; if you limit the rotary to a 'sane' rpm for =
aviation use (say, 7000), and use a prop that's typically used on =
smaller 2 place homebuilts with Lycs (meaning 2700 rpm at the prop for =
75% power at altitude), then somewhere around 2.6-1 makes sense. On the =
RVs, even the 180 & 200 HP Lycs use constant speed props that are 74" =
dia. & turn 2700 rpm.
> =
https://shop.vansaircraft.com/cgi-bin/shop.cgi?ident=3D1606438205-166-687&=
browse=3Dprops&product=3Dcsprop-hartzell
> Only reason to turn under 2700 in cruise is if you're highly motivated =
(self or legislated) to keep noise to a minimum.
>=20
> Another motivator to keep rpms up is that a lot of prop carvers are in =
uncharted territory when you ask for a 2200 rpm prop. (Right, Sam H. ?) =
;-)
>=20
> When I ran numbers treating the Renesis as a 180 HP engine (~6000 rpm, =
supposedly the minimum bearing load rpm) and swinging the big 76" dia =
prop, I was wishing for a 2.4-1 ratio (~2500 prop rpm).
>=20
> Charlie
>=20
> On 11/26/2020 5:09 PM, Stephen Izett stephen.izett@gmail.com wrote:
>> 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.
>>=20
>> What am I missing?
>>=20
>> Steve
>>=20
>>=20
>>> 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/
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http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>>=20
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>>=20
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>=20
>=20
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>=20
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