-------------- Original message from "Ed Anderson" <eanderson@carolina.rr.com>: --------------


> Bob, the compression for the turbo rotors on some models of the 13B were as
> low as around 8.4:1. If that is also true of the 13B, then my opinion is
> you will see a considerable improvement in power over the low compression
> rotors. I went from the 9.4 to the 9.7:1 rotor on my two rotor and liked
> the results. I know that small a difference in compression should not
> translate into a terrific power increase, but it seemed make a noticeable
> difference. Now the challenge is getting the 9:7:1 - there are not many
> used ones out there and those that are can be very worn. Make certain you
> check the apex seal slot wear measurements before you stick any in your
> engine (actually all of its seal slots should be ch ecked) if using used
> ones. If apex seal slot wears past the limit and if you are using the
> somewhat brittle stock apex seals, they will break - don't ask me how I
> know.
>
>
> One thing make certain you are getting 9:7:1 rotors. If you place a
> straight edge across the compression dish and then measure vertically down
> until you hit the top of the rotor it should be around 3.8-4 mm. If it
> measure more than that it may be the lower compression 9.4:1. But, even the
> 9.4:1 should make a noticeable difference IF the stock turbo 20B is using
> the 8.4:1
>
> Ed
> ----- Original Message -----
> From: "bob.kaufmann"
> To: "Rotary motors in aircraft"
> Sent: Sunday, February 03, 2008 4:44 PM
> Subject: [FlyRotary] Low compression rotors
>
>
> > Gang
> >
> > I have a 20B that I have taken the turbos off and will be using it in an
> > aircraft, a RV-10. A friend of mine said that I should use the 9.7
> > compression rotors instead of the turbo rotors. What say you all?
> >
> > I have pulled the engine off to powder coat the engine mount and if I'm
> > going to switch rotors, now is the time before I hang the engine again. I
> > have the flat plate on milling machine so I could make plates for the 20B
> > if
> > people wanted. I think I would be competitive. I would like to do them
> > in
> > groups of ten if people are interested.
> >
> > Bob K
> > Finished except all the parts aren't together yet.
> >
> >
> > --
> > Homepage: http://www.flyrotary.com/
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>
> < BR>> --
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