Brodhead Pietenpol Association

Original Posted By: dave rowe
Subject: Pietenpol-List: Changing the subjectHey guys!This is sort of changing the subject. Considering the current subject matter I will ask a dumb question. Am I supposed to cover the belly of this beast (underside of the fuse) with fabric or leave it wood? I would assume you are supposed to cover it, but I saw a fly baby the other day, and the fabric stopped at the bottom of the fuselage. I am going to have an aluminum access panel from the pilots seat aftall the way the tail wheel.MaxArlington, TX.________________________________________________________________________________Date: Fri, 06 Feb 2004 18:08:27 -0800

Original Posted By: Andimaxd(at)aol.com
Max,Covering the belly is optional. I've seen it both ways.Dale and I put a fairing strip down the center of the belly then coveredwith fabric. It looks better than an uncovered belly.Greg Cardinal in Minneapolis ----- Original Message -----

Original Posted By: "Shawn Wolk"
Max,Not a dumb question.Agreed, the belly does look better covered.The other side is, it is easier to inspect bolt heads and nuts sticking thoroughthe floor, uncovered.Why are you running the inspection panel all the way back?Skip, in Atlanta----- Original Message ----- Hey guys!This is sort of changing the subject. Considering the current subject matter Iwill ask a dumb question. Am I supposed to cover the belly of this beast (underside of the fuse) with fabricor leave it wood? I would assume you are supposed to cover it, but I sawa fly baby the other day, and the fabric stopped at the bottom of the fuselage.I am going to have an aluminum access panel from the pilots seat aft all theway the tail wheel.MaxArlington, TX.________________________________________________________________________________

Original Posted By: BARNSTMR(at)aol.com
Subject: Re: Pietenpol-List: Changing the subjectMax,I am also planning to have an access panel under the belly for getting into the elev bellcrank turnbuckles etc. Seems to make good sense.Terry Bowdenph (254) 715-4773fax (254) 853-3805________________________________________________________________________________

Original Posted By: "Jack Phillips"
Subject: Re: Pietenpol-List: Changing the subjectAlso, I might add that I plan to use a center fairing strip and cover the belly with fabric from the firewall to the tail, with only a small access panel(maybe one bay) for access to the belcrank area. Fabric on the belly is desireable for cleaning off the oil spatters and fuel drips that are inevitable, no matter which engine you use. I'd prefer to clean off of fabric, rather than allow those intrusive fluids to soak into thebelly plywood. Terry Bowdenph (254) 715-4773fax (254) 853-3805________________________________________________________________________________

Original Posted By: owner-pietenpol-list-server(at)matronics.com
I've also included a belly access panel, as Mike Cuy did on his. There issimply too much important stuff that you need to be able to inspect andadjust in the area behind the rear seat. I don't think I would take it allthe way back to the tail, though - too heavy, and there is nothing backthere that should ever need adjustment. Here is a picture showing my accesspanel area.Having done a few "Owner assisted annual inspections" on my Cessna 140, Iknow how important it is to be able to have ready access to the controlsystem for inspection and lubrication annually.I put mine between two stringers that I added on the belly. I think theyadd slightly to the look of the airplane, rounding it out slightly. Theyalso get the fabric up over the various bolts and nuts in the cockpit area.I added inspection rings in the region of the bolts attaching the controlsystem components, in case I ever need access to those nuts.Jack Phillips-----Original Message-----

Original Posted By: "Cy Galley"
Subject: Re: Pietenpol-List: Changing the subjectIn a message dated 2/6/2004 11:05:11 PM Central Standard Time, csfog(at)earthlink.net writes:> Why are you running the inspection panel all the way back?> Skip, in Atlanta> Skip:I want to be able to have easy access to the bell crank assembly, turn buckles and assorted hardware. I also want to have access to the tail cone forinspection and clean-out of foreign object, nests etc. I am a fairly big personand like the idea of being able to get my little grubbies in every little nookand cranny. I read about this idea a long time ago, and it just made sense. Something about the guy having a fuel leak and being able to take this oversize access panel off from behind the pilot seat all the way aft to facilitatedrying it out. With some dzus fasteners, no one will even know it's there, except me, during inspections.________________________________________________________________________________

Original Posted By: Jack Phillips
You are also working way too late... 11:45PM is what the clock says and it is darkthru the windows! ----- Original Message -----

Original Posted By: dave rowe

Original Posted By: Jack Phillips
----- Original Message -----

Original Posted By: Jeff Cours

Original Posted By:> Jeff Cours
I worked with that sort of ground test vehicle in college. You can getgood data from it, but it is a bit tricky. At Mississippi State we used avery old Buick roadmaster with all of the body panels removed so as toaffect the air as little as possible. You want the test sample to see onlyundisturbed air. This means it has to be quite a ways up there. It alsomeans the vehicles CG will be quite high so we had to throw in some ballastdown low. A DAQ system recorded a couple of load cells installed on amechanism very much like a wind tunnel balance. However the data wasnowhere near as clean as what you get out of a tunnel so we had to do a lotof averageing. Reducing the data was a chore; essentially you look at aquick plot, try to find several steady seconds, and average those numbers. Periods of acceleration, decelearation and bumps in the road (or in ourcase the runway) need to be thrown out. Also, when the model gets largecompared to the vehicle things can get spooky.Good luck with your experiment. You can get good data if you are carefulbut it is not as easy as it sounds like it might be.Kevinwww.airminded.net> [Original Message]

Original Posted By: "Kevin Holcomb"
Atta way Kev.... The real world is sometimes quite different than thehypothetical stuff. I liked your description of the test vehicle and whatyou had to do with CG to test sections. Good stuff,Weav----- Original Message -----

Original Posted By: Rcaprd(at)aol.com
Subject: Re: Pietenpol-List: Changing the subjectIn a message dated 2/6/04 7:46:30 PM Central Standard Time, Andimaxd(at)aol.com writes:>I covered my belly (on the airplane ) with fabric, to protect the plywood from all the fluids and exhaust the engine barfs out. I installed two standard access covers under the bellcrank, and made some adjustments to the turnbuckles going up to the control stick, in there last spring. I don't likethe thought of a huge access panel all the way back...what if it blew off ?? Chuck G.________________________________________________________________________________

Original Posted By: Clif Dawson
Subject: Re: Pietenpol-List: Front & CenterIn a message dated 2/6/04 6:51:03 AM Central Standard Time, Michael.D.Cuy(at)grc.nasa.gov writes:>Mike,Very good points !! I'm afraid I would have to personally escort someone like that, out of the area !! I'll vote for a spot over by Theater in the Woods!!Chuck GantzerNX770CG________________________________________________________________________________Date: Sun, 08 Feb 2004 01:17:17 -0800

Original Posted By: "Fred Weaver"
> Subject: Pietenpol-List: thinking about airfoils>>> Hi, everyone ->> I was thinking about airfoils last night, and it occurred to me that not > having access to a wind tunnel isn't really a limitation if someone > wants to test the FC-10, since automobile highway speeds are a pretty > good match for Pietenpol airspeeds. If you had the proper test rig, you > could mount an airfoil section in, say, the bed of a pickup truck, > poking up well above the cab to get it into clean air, and collect data > at night on a smooth section of rural highway.>> Then I started thinking that the test rig might not be that much of a > problem, either. For a simple thought experiment, I went through how you > might measure lift at different airspeeds and angles of attack. Since a > 29 foot wing can lift a 1,000lb Piet, if we ignore edge effects (mostly > 'cause I don't know enough to know how to figure them out), that says > that a 2 foot wing section ought to be able to lift somewhere in the > neighborhood of 70lb. So, let's say you put a bathroom scale in the > truck bed. On that scale, you put a 200lb block of concrete, just to > keep the weights in the region where bathroom scales are mostly linear. > Poking out of the concrete is a pole that's high enough to get the wing > section into clear air. On top of the pole is a 2' wide section of full > cord FC-10, pivoted to let you adjust the angle of attack, maybe with a > threaded rod to hold it at the desired angle. Also, imagine some > bracing, with a ring around the pole to let the pole slide up and down, > just to keep the rig from falling over. Your test run would be to set > the AOA and note the scale reading at speed 0. Then drive a set of test > point speeds, say every 5 MPH, and have someone else read the scale. At > the end of the run, stop, readjust AOA, and repeat for the next series. > I could also imagine variations on the test rig that'd let you measure > pitching moment.>> It sounds like the things this project would really need are someone who > knows enough about the practical end of aero engineering to know exactly > what to measure and how to do it, and someone who's willing to devote > the time to building the test rig and collecting the numbers. (Neither > of whom are me, unfortunately.)>> - Jeff>> > > > > > >________________________________________________________________________________

Original Posted By: Rcaprd(at)aol.com
> > Subject: Pietenpol-List: thinking about airfoils> >> >> > Hi, everyone -> >> > I was thinking about airfoils last night, and it occurred to me that not> > having access to a wind tunnel isn't really a limitation if someone> > wants to test the FC-10, since automobile highway speeds are a pretty> > good match for Pietenpol airspeeds. If you had the proper test rig, you> > could mount an airfoil section in, say, the bed of a pickup truck,> > poking up well above the cab to get it into clean air, and collect data> > at night on a smooth section of rural highway.> >> > Then I started thinking that the test rig might not be that much of a> > problem, either. For a simple thought experiment, I went through how you> > might measure lift at different airspeeds and angles of attack. Since a> > 29 foot wing can lift a 1,000lb Piet, if we ignore edge effects (mostly> > 'cause I don't know enough to know how to figure them out), that says> > that a 2 foot wing section ought to be able to lift somewhere in the> > neighborhood of 70lb. So, let's say you put a bathroom scale in the> > truck bed. On that scale, you put a 200lb block of concrete, just to> > keep the weights in the region where bathroom scales are mostly linear.> > Poking out of the concrete is a pole that's high enough to get the wing> > section into clear air. On top of the pole is a 2' wide section of full> > cord FC-10, pivoted to let you adjust the angle of attack, maybe with a> > threaded rod to hold it at the desired angle. Also, imagine some> > bracing, with a ring around the pole to let the pole slide up and down,> > just to keep the rig from falling over. Your test run would be to set> > the AOA and note the scale reading at speed 0. Then drive a set of test> > point speeds, say every 5 MPH, and have someone else read the scale. At> > the end of the run, stop, readjust AOA, and repeat for the next series.> > I could also imagine variations on the test rig that'd let you measure> > pitching moment.> >> > It sounds like the things this project would really need are someone who> > knows enough about the practical end of aero engineering to know exactly> > what to measure and how to do it, and someone who's willing to devote> > the time to building the test rig and collecting the numbers. (Neither> > of whom are me, unfortunately.)> >> > - Jeff> >> >> >> >> >> >> >> >>>________________________________________________________________________________