Brodhead Pietenpol Association

Original Posted By: "Dick Navratil"
Pieters,Keeping in mind that the only dumb question is the one that didn't get asked, here's a question for the Continental putt-putt guru's out there I replaced my 72 x 42 Hegy recently on the Continental A-75 with a PerformanceProps 73 x 39, to get the static and climb rpm up into the A-75's rpm range. Thenumbers came out as follows in Florida summer late-in-the-day conditions: Hegy 72 x 42 Perf.PropsStatic 2150 2450climbout @ 50mph 2200 2550WOT level flight 2350 somewherepast redline....I didn't go there......cruise @ 65 mph 2150 2500The original Hegy was a good A-65 prop, but didn't let the A-75 rev up to get it'sextra 10 hp. The Performance Prop seems to be a good A-75 climb prop, whichwas the goal, but...........Continental lists redline at 2300 and cruise at 2150 for the A-65. The Hegy wasan A-65 prop and performed as such.The same manual lists A-75 redline at 2600 and cruise at 2300 (a 300 rpm difference??)With the new prop, 2450-2500 is achieved at about the same throttle setting aswas used previously to get a 2150-2200 rpm cruise with the old prop. Oil pressureand temp are exactly the same as before (35 psi and 145-150F), and it feelshappy & smooth. Now the question:Am I doing any harm to this engine running it this way? I can't understand whyContinental's A-65 redline and cruise rpm are only 150 rpm apart, while theA-75 numbers are 300 rpm apart. If I pull back to 2300 rpm, I'm at what feelslike 50-60% throttle. (hard to say without a manifold pressure guage, but thethrottle is pulled waaaay back).Thanks in advance for any input. My gut tells me this situation is OK, but there'sa lot of tribal knowledge out there & it never hurts to ask....Dave MordecaiPanacea, FLNX520SF ________________________________________________________________________________

Original Posted By: "Phillips, Jack"

Original Posted By: "Skip Gadd"
Ken;I have acquired an A75 that is being gone through right now so I'm learning about them. As I understand it, the main difference between the A65 and the A75 is that the 75 has a hole drilled in the rod big ends to increase the oil flow, allowing the higher RPM needed to get the additional HP.There is some vagueness as to whether the venturi size in the Stromberg carb needs to change as well, because the Continental service letter does not mention it for the A75. They do clearly show the 1-5/16" venturi needed for the C75 but it has increased displacement (larger bore) and develops its rated HP back down in a lower RPM range than the A75. My assumption is that the A75 should use the same 1-1/4" venturi as the A65.I guess what I'm saying is that if you operate your A75 at its rated RPM (full power at 2600 RPM, cruise at 2350), you should be getting rated HP and still be OK on lubrication. I noted from the engine specs that the C75's max and cruise RPM are the same... 2275. There is no substitute for cubic inches ;o)Be sure you check your mechanical tach with an optical one though. I found that the tach on 41CC was reading about 200 RPM high at cruise RPM, meaning that I was leaving power on the table some of the time.Oscar ZunigaSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net_________________________________________________________________Get a FREE small business Web site and more from Microsoft Office Live! ________________________________________________________________________________

Original Posted By: "Brian Kraut"
Gardiner, The ground plane is the three green looking strips in the pictureattached to my original post. They are 1" X 23" 13 thousands aluminum usedin the 'made on site' gutter industry. The ground plane, com antenna andELT antenna are all in the fuse behind the pilot. I don't see why your alumfoil plan should not work, you can use the same ground plane for the ELT.Skip> > skip, can you tell me more about your ground plane and location? I amalmost > ready to start covering.thanks, gardiner mason. ps I plan on putting anant. > on top of of the turtle back headrest for my icom handheld. I was toldthat > I could line the fibreglass headrest with alum foil for the groundplane.>________________________________________________________________________________

Original Posted By: Rcaprd(at)aol.com
Subject: Re: Pietenpol-List: Continental A-75 cruise rpm question There are some other differences in the A65 and A75 engines. I don't understand why, but the piston pins (wrist pins) are a smaller diameter for theA75 than the A65. This spec, as well as ALL the specs for these two engines are called out in the Continental Motors 'Overhaul Manual and Parts Catalog'. If you have one of these engines, this is a MUST HAVE catalog.Chuck G.NX770CG________________________________________________________________________________

Original Posted By: "Dale Johnson"
Subject: Re: Pietenpol-List: tail fittingsBrian,There is No need to add blocks to stiffen up the ribs in the tail.I put the fittings for the cables Under the Fabric. _http://nx770cg.com/Unique.html_ (http://nx770cg.com/Unique.html) Chuck G.NX770CG________________________________________________________________________________

Original Posted By:> Steve Ruse
SteveAll radio work better with a ground plane in the air or on the ground.My car radio has a ground plane because it has a plastic body.With a ground plane you double the range of your ELT.Dale > [Original Message]

Original Posted By: "Gene & Tammy"
Subject: Re: Pietenpol-List: Continental A-75 cruise rpm question I have a 75 cont and a beech roby variable pitch prop and could not get it to turn up to static rpms until I drill the main jet out two numbers higher. I think .057 on a marvel schebler carb. Just a thought. Ken in Iowa waitingfor the corn to dry down.________________________________________________________________________________

Original Posted By: Rcaprd(at)aol.com
> Subject: Re: Pietenpol-List: ELT Location>>> I'm a little confused here.>> My understanding is that a ground plane was only needed in the air, > and that on the ground, the earth functions as a ground plane. When > flying, the ground plane is a "substitute" for earth.>> That is why you can use a handheld radio on the ground without > attaching a 24" diameter sheet of aluminum to the bottom of the > radio...that would tend to get in the way.>> I don't plan on using my ELT in the air. Does it really need a groundplane?>> Thoughts?>> Steve Ruse> Norman, OK>> Quoting Skip Gadd :>> >> > Gardiner, The ground plane is the three green looking strips in thepicture> > attached to my original post. They are 1" X 23" 13 thousands aluminumused> > in the 'made on site' gutter industry. The ground plane, com antenna and> > ELT antenna are all in the fuse behind the pilot. I don't see why youralum> > foil plan should not work, you can use the same ground plane for theELT.> > Skip> >> >> >>> >> skip, can you tell me more about your ground plane and location? I am> > almost> >> ready to start covering.thanks, gardiner mason. ps I plan on putting an> > ant.> >> on top of of the turtle back headrest for my icom handheld. I was told> > that> >> I could line the fibreglass headrest with alum foil for thegroundplane.> >>> >> >> >> >> >> >> >> >>>________________________________________________________________________________