---------------------------------------------------------- KIS-List Digest Archive --- Total Messages Posted Sat 02/19/11: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:12 AM - Re: Re: CATTO 3 bladed prop (Bill Schertz) 2. 06:01 AM - Sun-N-Fun?? (Galin Hernandez) 3. 07:51 AM - Re: Sun-N-Fun?? (ALFRED ROSA) 4. 09:54 AM - Re: Re: CATTO 3 bladed prop (Scott Stearns) ________________________________ Message 1 _____________________________________ Time: 04:12:14 AM PST US From: "Bill Schertz" Subject: Re: KIS-List: Re: CATTO 3 bladed prop Galen, I have no experience on a KIS with a 3 blade prop, but a friend of mine has an E-racer that he used a Catto 3 blade prop on, and he was very pleased with the performance. Bill Schertz KIS Cruiser #4045 N343BS Phase I testing From: Galin Hernandez Sent: Friday, February 18, 2011 6:39 PM Subject: Re: KIS-List: Re: CATTO 3 bladed prop Yes, I am aware of what you pointed out about the different props. But, I want to use a smaller diameter prop since I fly in and out of runways that are not very well kept. I have a constant struggle with nicks on my 76" prop. I installed prop guard on the leading edge. It lessened the problem, but it still exists more than I like. That is why I wanted a PIREP if anybody had a CATTO prop and how it performed. Galin On Fri, Feb 18, 2011 at 2:21 PM, BlueSkyFlier wrote: Hi Galin, As part of making a decision about my new propeller (and also because I wanted to do it) I created an performance model for the KIS which integrates propleller and airframe models. To my surprise and contrary to popular wisdom the results showed that (a) larger diameter is not necessarily always better and (b) 3 bladed props are rarely (if ever) better than 2 bladed props At normal operating RPMs the parasitic drag of the third blade easily negates the reduction in induced drag due to lower power loading per blade. So I would suggest staying with a two blade prop unless ground clearance issues makes 3 blades an unavoidable necessity. For any particular density altitude and RPM, there is an optimum prop diameter which maximises residual engine power across the speed range. The diameter determines the prop blade power loading which in turn determines the prop drag losses. Therefore, optimising diameter is equivalent to optimising prop drag losses across the speed range for chosen RPM and altitude. These non-linear characteristics of the propulsion system only become apparent when the airframe and propeller are integrated together. Regards, Alfred -------- _________________________________________ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=331443#331443 ========== rget="_blank">http://www.matronics.com/Navigator?KIS-List ========== http://forums.matronics.com ========== le, List Admin. ="_blank">http://www.matronics.com/contribution ========== ________________________________ Message 2 _____________________________________ Time: 06:01:00 AM PST US From: Galin Hernandez Subject: KIS-List: Sun-N-Fun?? Anyone going to Sun-N-Fun this year? I hope to be there Thu - Fri - Sat. Galin ________________________________ Message 3 _____________________________________ Time: 07:51:25 AM PST US Subject: Re: KIS-List: Sun-N-Fun?? From: ALFRED ROSA Since I now live 2 hours drive from Lakeville, I will definitely be there one of those days. If you give me your cell #, I'll get in touch when I'm there. Al Rosa On Sat, Feb 19, 2011 at 8:56 AM, Galin Hernandez wrote: > Anyone going to Sun-N-Fun this year? I hope to be there Thu - Fri - Sat. > > Galin > > * > > * > > ________________________________ Message 4 _____________________________________ Time: 09:54:32 AM PST US From: Scott Stearns Subject: Re: KIS-List: Re: CATTO 3 bladed prop 3 bladed props look cool, no doubt about that.- I think that's basically why they are used on most piston airplanes. - - I think it really helps with the pushers to reduce noise and vibration -since you don't have both blades hitting the wake of the wing at the sam e time.- Anyhow, just trivia.. - Scott --- On Fri, 2/18/11, Robert Reed wrote: From: Robert Reed Subject: Re: KIS-List: Re: CATTO 3 bladed prop Well, there is one thing you won't have to worry about with the Catto 3 bla ded is any significant weight increase. -It is a very light prop. -I kn ow all the issues of 2 vs. 3 but my main reason for the Catto 3 blade was t he quiet operation of the 3 bladed prop. -My wife has migranes and I have made several changes to reduce cabin noise. -Besides, it's one of the se xiest looking props around. Bob Sent from my iPhone On Feb 18, 2011, at 5:25 PM, Scott Stearns wrote: I remember when the 'new' cessna 182 came out.- The 3 bladed propeller wa s an option.- The POH showed no difference in performance between the two and three bladed propellers, except the 3 bladed propeller was 40 pounds h eavier and a $10,000+ option.- I've never seen a new 182 with a two blade d propeller and a lot of older 182 have converted to three bladed props.- It does look cool.... - Scott --- On Fri, 2/18/11, BlueSkyFlier wrote: From: BlueSkyFlier Subject: KIS-List: Re: CATTO 3 bladed prop Hi Galin, As part of making a decision about my new propeller (and also because I wan ted to do it) I created an performance model for the KIS which integrates p ropleller and airframe models. To my surprise and contrary to popular wisdom the results showed that (a) larger diameter is not necessarily always better and (b) 3 bladed props are rarely (if ever) better than 2 bladed props At normal operating RPMs the parasitic drag of the third blade easily negat es the reduction in induced drag due to lower power loading per blade. So I would suggest staying with a two blade prop unless ground clearance issues makes 3 blades an unavoidable necessity. For any particular density altitude and RPM, there is an optimum prop diame ter which maximises residual engine power across the speed range. The diameter determines the prop blade power loading which in turn determin es the prop drag losses. Therefore, optimising diameter is equivalent to op timising prop drag losses across the speed range for chosen RPM and altitud e. These non-linear characteristics of the propulsion system only become appar ent when the airframe and propeller are integrated together. Regards, - - - - - - Alfred -------- _________________________________________ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=331443#331443 http://www.matronics.com/Nav- - - - - - ---- MATRONICS WE B - - - - - - - - - - &nbsf="http://www.matronics.com /contribution" target=_blank>http://www.matr========= =========== ========= ef="http://www.matronics.com/Navigator?KIS-List">http://www.matronics.com /Navigator?KIS-List ========= ums.matronics.com">http://forums.matronics.com ========= http://www.matronics.com/contribution">http://www.matronics.com/contributio n ========= =0A=0A=0A ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message kis-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/KIS-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/kis-list Browse Digests http://www.matronics.com/digest/kis-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.