---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Mon 07/23/18: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:00 AM - Re: Re: Ford Crankshaft Choice (skipgadd@earthlink.net) 2. 07:44 AM - Re: Ford Crankshaft Choice (braywood) 3. 08:14 AM - Re: Ford Crankshaft Choice (taildrags) ________________________________ Message 1 _____________________________________ Time: 05:00:22 AM PST US From: "skipgadd@earthlink.net" Subject: Re: Pietenpol-List: Re: Ford Crankshaft Choice John, Just back from Brodhead, so the late reply. The thing about Piets is they will almost always be tail heavy. My personal building philosophy is not to worry about weight ahead of cg, but I will have an A65 that is lighter than your Ford A. The other thing is your personal weight, the bigger you are the more weight you will need up front. Skip -----Original Message----- >From: John C Black >Sent: Jul 18, 2018 5:42 PM >To: pietenpol-list@matronics.com >Subject: Re: Pietenpol-List: Re: Ford Crankshaft Choice > >I have heard from 2 guys off list. > >I learned that using a 76x44 prop or a 78x42 prop. Model A engine turns 2100 RPM on takeoff, cruises at 1700-1800 RPM, probably never exceeds 2200 RPM. > >I took my model A Ford car (pic Below) out and ran the engine at 1700-2200 RPM and drove at those RPMs. The Model A engine in the car has no counterweights on the crank. The engine has been balanced. I did not experience any harmonic vibration. My rearview mirror amplifies the vibration and serves as a great observable indicator. > >Based on this test, I am leaning toward using the 1932 Model B crank without counterweights. I figure saving 12-14 pounds is a big deal. > >John > > >On Jul 18, 2018, at 1:29 PM, taildrags wrote: > > >John; I'm really surprised that no one has replied to your query about the crank, since there are quite a number of those engines out there and plenty of hands-on engine rebuilders too. I know Ernie Moreno up here in Independence is building up a Ford to put on his Piet to replace the Franklin that he's got on it now. The extra weight up front will help Ernie's airplane with tail-heaviness. > >-------- >Oscar Zuniga >Medford, OR >Air Camper NX41CC "Scout" >A75 power, 72x36 Culver prop > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=481734#481734 > > ________________________________ Message 2 _____________________________________ Time: 07:44:34 AM PST US Subject: Pietenpol-List: Re: Ford Crankshaft Choice From: "braywood" Hello Oscar - I am still struggling with the theoretical weight and balance for my aircraft; so I am not pretending to be an expert or suggest others are incorrect. For me, the issue of CofG is a question of where you locate the wing - if the aircraft is tail heavy (or like me, the pilot is tail heavy....), the wing needs to go back. If you are changing the engine in an aircraft, then does not the W&B needs to be a clean sheet? I would think that every pound or Kg we add, is detrimental to performance. Opting for a heavier solution for a part of the aircraft seems counterproductive. Is it not better to relocate the wing to provide the correct CofG location for the lowest aircraft weight? I can understand wanting to have the cabane struts vertical, but not at the expense of the safety or performance of the aircraft. What am I missing?? Mark Bowler Read this topic online here: http://forums.matronics.com/viewtopic.php?p=481815#481815 ________________________________ Message 3 _____________________________________ Time: 08:14:06 AM PST US Subject: Pietenpol-List: Re: Ford Crankshaft Choice From: "taildrags" Mark; you are not missing anything. Your comments are correct, and the wing can be repositioned to adjust the CG. One negative to shifting the wing aft is that it makes getting into the cockpit just a bit more challenging, but a hinged flop or a cutout takes care of that. It's the builder's choice, like so many things about experimental aviation. "Ya pays yer money, ya takes yer choice". -------- Oscar Zuniga Medford, OR Air Camper NX41CC "Scout" A75 power, 72x36 Culver prop Read this topic online here: http://forums.matronics.com/viewtopic.php?p=481816#481816 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message pietenpol-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Pietenpol-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/pietenpol-list Browse Digests http://www.matronics.com/digest/pietenpol-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.