Received-SPF: none
 receiver=logan.com; client-ip=65.166.240.5; envelope-from=jackoford@theofficenet.com
Message-ID: <00c701c57479$7cfd3140$6a01a8c0@jack>
From: "Jack Ford" <jackoford@theofficenet.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1002462@logan.com>
Subject: Re: [FlyRotary] planetary gear ratios
Date: Sat, 18 Jun 2005 19:49:13 -0700
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Ernest,

Seems to me that one tooth on the ring gear will be displaced by one tooth
on the sun gear, without regard to intermediate idlers: 74/34 = 2.1765. I
think you have a 2.17 planetary set.

I don't understand the addition of unity.

Jack Ford


----- Original Message ----- 
From: "Ernest Christley" <echristley@nc.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, June 14, 2005 8:24 PM
Subject: [FlyRotary] planetary gear ratios


> I ran across some information in one of the scientific newsgroups on how
> to calculate the gear ratio of a planetary gear set.
>
> ratio = 1 + r / s
>
> where: r = number of ring gear teeth
>            s = number of sun gear teeth.
>
> I haven't replace my 3-pinion gear set with a 6-pinion set, because I've
> not been able to positively identify it to where I could call out a part
> number.  Order strange gearset from the internet is not what I consider
> an efficient way to spend money.  So I went out and counted.  74 teeth
> on the ring and 34 on the sun.
>
> 1+74/34 = 3.176
>
> That is not the 2.17 OR the 2.85 from the Ford gear sets.  Is it
> possible that the one isn't added in standard practice, so that what I
> actually have is the 2.17 gear set?
>
> -- 
> This is by far the hardest lesson about freedom. It goes against
> instinct, and morality, to just sit back and watch people make
> mistakes. We want to help them, which means control them and their
> decisions, but in doing so we actually hurt them (and ourselves)."
>
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>
>