----- Original Message -----

From: George Lendich

To: Rotary motors in aircraft

Sent: Thursday, April 14, 2005 6:27 PM

Subject: [FlyRotary] Re: Fw: Rx-8 Rotors useable in 91 13B?

Ed.

I finally paid $249.06 Aust if you add 23% (approx exchange rate )you get $306 - so the $322 sounds more like it. Aim for 30% off recommended retail on everything!! That will get you close to Trade Price.

 

I checked the height of the Apex seal groove and it is 9.5mm ( .374")

Bill agrees that EDM ( wire cut) would be the better option, so I will go that way, but am yet to confirm prices. You should find wire cutters everywhere - their all over the place around here.

 

I would love to use the ceramics, but I did get some seals from Tracy Crook.

 

be careful with the corner side seals the later model Nitrated housings will stand-up to later model seals and springs, but earlier model flame hardened housings won't. Definitely don't use the RX8 corner seals.

 

Another one is that the RX8 front ( bully) bolt is longer and probably explains why Tracy had a concern fitting the RX8 pulley and timing gear - he was probably using a RX7 bolt. It's longer by 1/2".

George

----- Original Message -----

From: Ed Anderson

To: Rotary motors in aircraft

Sent: Thursday, April 14, 2005 10:29 PM

Subject: [FlyRotary] Re: Fw: Rx-8 Rotors useable in 91 13B?

Thanks for the information, George

 

The prices I am getting on the Rx-8 rotors here have ranged from $322 USD from Mazdatrix to $378.86 from a Mazda discount parts place (they pay the shipping).  MAzdatrix apparently got by running the standard RX-7 ceramic apex seals in the Rx-8 rotors.  I would assume they reduced the height of the seals unless the ceramic seals are narrower than metal seals since they have not indicated finding anyone to mill the slots deeper as yet.

 

Ed A

----- Original Message -----

From: George Lendich

To: Rotary motors in aircraft

Sent: Thursday, April 14, 2005 3:45 AM

Subject: [FlyRotary] Re: Fw: Rx-8 Rotors useable in 91 13B?

Well Richard, Bill and All,

 

I have to bow my head in shame and confess I one again believed what I have been told to be true - when in fact it wasn't.

 

I guess I can say the RX8 rotor IS lighter, but not by much. It weighs in at 4241 Grams or 9.33lbs. A reduction of a bout 2% from the lighter 89/91rotors.

 

Again I made an error, the RX8 rotor appears to be symmetrical in the compression depression. So the chap who runs them backwards may be OK in doing so.

 

My advice ( I think I will use this statement more often) is that the depth of cut for the RX7 is 9.5mm ( appears to be correct) the RX8 appears to be 6.25mm, by my measurements. An additional 3.25 cut in depth is required for the earlier Apex seals..

 

Width of the RX8 Rotor is 79.75mm compared to an old rotor I have here that's 79.65mm The RX rotor is .1mm bigger ( approx) 

 

Anything else you chaps need - I'm depressed as I was looking forward to that Rotor weight savings.

George ( down under)

Kelly,

absolutely!

 

Richard Sohn
N-2071U

 

 

----- Original Message -----

From: Kelly Troyer

To: Rotary motors in aircraft

Sent: Wednesday, April 13, 2005 6:41 PM

Subject: [FlyRotary] Re: Fw: Rx-8 Rotors useable in 91 13B?

Richard,

     But we would include the side seals and springs ,end seals,springs (and plugs ),

and oil seal rings and respective O-rings ? Is that asumption correct ?

--
Kelly Troyer
Dyke Delta/13B/RD1C/EC2

-------------- Original message from "richard sohn" <unicorn@gdsys.net>: --------------

George,

I got the information from my engineering education, and also Leon confirmed it in one of his recent postings on the subject.

One more thing, the difference between the two rotors balancing each other and needing balance weights anyway, is static balancing vs. dynamic balancing.

 

Richard Sohn

N-2071U

----- Original Message -----

From: George Lendich

To: Rotary motors in aircraft

Sent: Wednesday, April 13, 2005 5:02 PM

Subject: [FlyRotary] Re: Fw: Rx-8 Rotors useable in 91 13B?

Richard,

This goes against my advice as all components in movement affect the rotating mass.

It would be like not allowing for rings in a piston in the balance equation.

However I will check on that aspect. Where did you obtain that information

George ( down under)

From: George Lendich

To: Rotary motors in aircraft

Sent: Wednesday, April 13, 2005 12:02 AM

Subject: [FlyRotary] Re: Fw: Rx-8 Rotors useable in 91 13B?

Bill,

If you find out before I do will you let me know about the additional depth to be cut.

On the balancing; I have to cover all that with my one rotor ( no biggie), I can give you all that stuff a little down the track it will only require lightening the counter balance weights a little.

 

The e-shaft is the same, the rotors lighter = lighter balance weights.

There may be some oil volume difference (read weight) , but I should have that soon, as well the rotor weight. BTW Tracy's apex seals are 33 grams ( per rotor) - got them to-day.

 

Has anyone got a set of new Mazda apex seals handy to weigh - I guess there wouldn't be much in it anyway - just curious!

 

George ( down under) 

I am going to look into this a bit more and find out how much to mill a rotor.  A lighter rotor => more rpms without increasing stress?

 

Ed Don't forget lighter rotors would require different balance weights. I have heard from various sources that the Renesis rotor was lighter and then that they weigh the same! Both from usually reliable sources, go figure.

Bill Jepson

 

George,

the apex seals do not go into the balance equation because they are not attached to the rotor.

Just my 2c.

 

Richard Sohn
N-2071U