|
|
Here's an even better one. I have a 93/94 engine. I have two counterweights I could use for this engine. They differ by 2 oz. (one has two holes drilled on the counterweight flange, the other 2, so it WAS balanced once for a particular engine assy). Which should I use, or do I need to get a dynamic balance of the assy after I clean up the rotors? Who does that-I saw a write up of balancing the assy.....? Is there an easy way I can determine which is best?
Marc Wiese
From: David Leonard <wdleonard@gmail.com>
Date: 2005/10/04 Tue PM 07:21:08 EDT
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Telling rotors apart - Never trust Atkins!
On 9/28/05, Kelly Troyer <keltro@att.net> wrote:
>
> Ed Anderson has a measurement to check the depth of the combustion
> depression in the
> face of the rotor to determine the compression ratio (the deeper one is
> turbo).......
>
How about it Ed, any info on this? Can it be used to tell the 9.4:1 86-88
rotors from the 9.7:1 rotors?
Bottom line check weight first then check the depth of the combustion
> depression........I have
> another way I use to determine what year my rotors are (all my engines are
> NA 86 to 91).....The
> combustion depression in the 86 to 88 is as cast in the rotor (slight
> grainy surface finish).....The
> 89-91 depression is machined and has straight machine marks.......
>
That is really interesting. My old rotors are supposed to be 1991 T2 rotors
but they have the cast appearance (However since I got them from Atkins I am
not really sure they gave me what they sold me). The rotors that Earnest
sent also have a cast appearance. But as I recall, the rotors in the engine
I rebuilt had the milling marks... hmmm.. if that is true the balance in my
current engine is all SNAFU. Are you sure that system is a valid way to do
the measuring?
So I just got back from weighing my rotors - Sure enough, the ones Atkins
sold me weighted in at 10.20 and 10.19 making them the 86-88 variety despite
the fact that I paid for a '91 engine. Worse, I have no idea what
counter-weights he decided to use. If it matched the rotors he sold me then
I have been running an unbalanced engine for the last 150 hrs. (that
explains part of why the wife won't fly in it)
Does anyone know what the correct weights of the counter weights should be
for a given year group? Or perhaps some other way of telling them apart?
BTW Ernest, the rotors you sent also weigh in at 10.18.
Dave Leonard
Check with Ed for his method to determine compression ratio as I do not
> have it at hand......I
> am attaching the rotor weight chart from "Mazdatrix" which will help (note
> weight does not
> include any seals or springs....just the bearing.........Hope this
> helps........Any more questions
> just ask !!
> --
> Kelly Troyer
> Dyke Delta/13B/RD1C/EC2
> *Engine* *Year* *Compression* *Weight (Grams)* *Weight (Pounds)* *12A *
> *76-82* *9.4* *4603* *10.15* *12A * *83-85* *9.4* *4353* *9.60* *13B* *
> 74-78* *9.2* *5253* *11.58* *13B* *84-85* *9.4* *5253* *11.58* *13B N/T* *
> 86-88* *9.4* *4553* *10.04* *13B Turbo* *86-88* *8.5* *4553* *10.04* *13B
> N/T* *89-92* *9.7* *4328* *9.54* *13B Turbo* *89-92* *9.0* *4328* *9.54* *13B
> T/T* *93-95* *9.0* *4328* *9.54*
>
> *NOTE: Weights are approximate, and include rotor bearing, but do not
> include any seals or springs. *
>
>
>
--
Dave Leonard
Turbo Rotary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html
http://members.aol.com/_ht_a/vp4skydoc/index.html
|
|