---------------------------------------------------------- Zenith701801-List Digest Archive --- Total Messages Posted Thu 05/07/09: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:28 PM - Prince P-tip propeller (Benjamin Q) ________________________________ Message 1 _____________________________________ Time: 07:28:31 PM PST US Subject: Zenith701801-List: Prince P-tip propeller From: "Benjamin Q" I am going to put a Jabiru 2200 on my 701. I have been looking into using a Prince P-tip propeller. Supposedly the p-tip allows a blade of smaller diameter to be as effective as a larger propeller because the tips "delays the tip vorticies which cause drag and turbulence within the propeller arc." They also claim that "a 72" diameter propeller without a P-TIP will give a volume of air from the propeller of approximately 68" in diameter; a P-TIP propeller will provide 72" of air volume." Additionally the propellers are said to include automatic pitch changing. "The propeller has a fixed pitch that relies on the forward pull of the propeller to automatically provide pitch change proportional to the amount of force being applied to the propeller disk." I have looked for information on some of the forums and the few that have the propeller seem to think that they give modest increases in performance and efficiency. The reason I am so interested in these propellers is because it seems like they might be something of a silver bullet for some of the weaknesses you find in the Jabiru. The Jabiru has to use a smaller prop because they spin up to 3300 rpms. You are limited to a 68" prop instead of the 72" prop you would usually find on a Rotax. Conveniently, 68" to 72" is the difference Prince claims for their props. Additionally the automatic pitch changing could help with the slightly weaker climb and takeoff performance of the Jabiru as compared to the Rotax. It's not that I think that the Jabiru will out perform the Rotax with the P-tip Prop, but I think it will get closer then if I put on the wood or ground adjustable composite sensenich that is packaged with Jabiru's Firewall Forward kit. I called Jabiru USA and talked to someone there and they didn't recommend the Prince P-tip. Their reasons were cost and consistency. They said that they got a few P-tip propellers one time and when they were put on the same engine, there was a slight difference in the max rpms in each propeller. I think they said about a 20 rpm difference, but I might be remembering that wrong. Anyway as far as cost, I'm not sure thats and issue either. The cost of the p-tip is actually less then the composite ground adjustable sensenich. I'm not entirely sure the consistency argument is that strong either. The propellers are individually made in order to be application specific, so you can expect there to be at least a slight difference in each propeller. I also called Prince Aircraft Company and talked to Lonnie Prince, the owner of the company. He told me that if I got the propeller and it wasn't performing like I thought it should, he would take it back and tweak it at the factory for free. The research I have done on the company seems good. They have been around for a while and have a pretty diverse business. Lonnie was a super nice guy, but as an engineer, I really wish that he had some hard core dynamic flow analysis, or experimental data I could take a look at. Realistically, I don't think Zenith has done hardcore dynamic flow analysis either. More of a wish on my part, not a criticism. I have heard that a few 601s have Prince P-tips with good results, but that's a little different in application. Has anyone tried a P-tip on a slower STOL Airplane? Has anyone else looked into this? Even with the non-recommendation from Jabiru, I am still leaning toward the P-tip. Professionally, I appreciate the way the design takes advantage of innovative engineering to turn out a unique solution. If anyone wants to take a look at the website its http://www.princeaircraft.com/TheProp.aspx I would appreciate any comments you guys have. Even though I have only had my kit for a month, I am already done with my rudder, horizontal stabilizer, elevator, slats and flaperons. I have two weeks of leave coming up and I hope to be through the wings and into the fuselage. Its amazing how much you can get done in a 12 hour day. The propellers have a 13 week lead time, so if this is the direction I am going, I need to do it soon, otherwise I'll be have a finished airplane in my garage waiting for a propeller. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=243102#243102 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message zenith701801-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Zenith701801-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/zenith701801-list Browse Digests http://www.matronics.com/digest/zenith701801-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.