FWIW, I was using a Prince 62"D x 66"P prop on the O-200 on my KR. IMHO, I thought it was about as perfect of a match as one could make. Easy cruise at 2550 rpm, but would turn up to 2750 if I wanted to run WOT. The down side to the Prince Props at the time was the lack of leading edge protection, so it tended to pick up rock chips and was easily damaged if you flew in heavy rain. On the other hand, I also found it quite easy to fill and repair.
It's difficult to compare one prop to the next, especially on a KR. Every prop manufacturer seems to caclulate their pitch differently, and every KR has a different drag component. I worked very hard at drag reduction on mine over the years with some very good performance results that just weren't there when I first started flying it. Less drag = more speed and higher rpms.
YMMV,
-Jeff Scott
Arkansas Ozarks
Sent: Wednesday, March 27, 2024 at 2:25 PM
From: "Phillip Matheson via KRnet" <krnet@list.krnet.org>
To: "KRnet" <krnet@list.krnet.org>
Cc: "Phillip Matheson" <phillipmathe...@bigpond.com>
Subject: Re: KRnet> prop size
From: "Phillip Matheson via KRnet" <krnet@list.krnet.org>
To: "KRnet" <krnet@list.krnet.org>
Cc: "Phillip Matheson" <phillipmathe...@bigpond.com>
Subject: Re: KRnet> prop size
Thanks Larry
The reason I asked, I have had all sorts of low RPM issues. I used
Thompson 60 x 70 = static 2100 wot 2400
Catto 60x 70 = 2300 and 2500 ( still the best prop)
APP 69x 68 using now 2300 and 2500 if I drop the nose
Any one have any better choices I would love to hear. But of course I can’t keep buying props.
So now just putting time on the engine and finishing phase one testing time
Phil
-- KRnet mailing list KRnet@list.krnet.org https://list.krnet.org/mailman/listinfo/krnetSent from my iPhone
On 28 Mar 2024, at 00:12, Larry Flesner via KRnet <krnet@list.krnet.org> wrote:
On 3/27/2024 12:03 AM, phillipmatheson--- via KRnet wrote:Hi Larry old friend, hope you are well. Good to hear your ex bird is going well
Do you remember her prop size, and static RPM and also MAX RPM straight and level please
Phil
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
211LF carries a Sterba prop, 60X68. I returned it early on to be re-pitched as it seemed rpm was a bit low. I couldn't tell any difference on return. It's been a while but I recall wide open level flight gave 2800 rpm, static around 2400. Zach has made a few changes as well as engine work so he could give more current info.
Larry Flesner
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