Pietenpol-List: Updated Email List Photo Share Available!
Posted: Sun Dec 02, 2001 12:18 pm
Original Posted By: Email List Photo Shares
Dear Oscar,Thanks for your comments to my remarks about the weights of Pietenpols.When I started my Piet, (about 6 years ago), I too had the vision of makingthe lightest possible airframe, strictly according to the original plans.But of course my situation was a little different than Bernie's Pietenpol.First, I live at over 7,000' in a valley surrounded by mountains on the westof over 14,000' (the continental divide) and on the north and east of over11,000'. The only way down is to go down the Arkansas Valley south and thensoutheast. So of course, I needed more power than a Model A engine wouldput out at this altitude;Second, contemporary airports that I fly into have a lot of concrete so Ineed brakes, to keep from running into that Gulfstream on the ramp. Mayberun under it? And of course a steerable tailwheel to try and remainstraight during rollout on landing.Third, the FAA requires a ELT and this requires the unit, batteries, wiring,mounting bracket etc.Fourth, due to building space and transportation limitations, gotta go withthe three piece wing.And it goes on and on, get the picture?So I decided to use an EA82 turbocharged and fuel injected engine to get offthe ground here and over the 14,000' mountains in case I decide to go toUtah. But this requires a prop reduction unit, however no one has made onefor this particular version of a Subaru engine. Now I got to design andmake one. Opps -- I can't afford to have the sprockets made out ofaluminum, better go with the stock steel one. Ouch! 70 pounds added to theengine. Oh well, the Piet is known as a tail heavy design anyway, it willnot be a problem. Now everyone knows that it is dangerous to hand start ageared engine, need a starter now, better also get the alternator to keepthe battery charged. Holy Moses, I forgot that the fuel burn will be higherand range reduced, better plan on another fuel tank too!So you see, Oscar, that it is a little like eating peanuts, you just can'tstop at one.Realizing that things were getting out of hand, I made up a simplespreadsheet program to keep track of weights and weight and balancethroughout the construction, and carefully weighed each component before andduring installation. Those that I didn't have on hand were estimated--howmany square feet of aluminum will I use for the cowl, etc.In spite of my best efforts, my empty weight has come out at 790 pounds.The saving grace is that the plane will have about the same performance as asuper cub. I calculated the rate of climb at 9,000' to be better than 1200ft/min. at gross and the center of gravity is at within limits.Now the point that I'm making is that in spite of our best efforts, we willend up building the Pietenpol to fit our own needs and the contemporaryflight environment with which we have to live. If weight is added to meetthese conditions, then we must look at the strength of the entire machineto be safe. Not only struts, and wing fittings, but landing gear, seats,tailwheel assembly and so on. I don't think that it is possible to count onwhat has been done in the past as a reliable indicator of the future.Cordially,John Dilatush, NX114D, only have the prop to go, now making a duplicator touse a great pattern I got from Duane Woolsey.I am in Salida Colorado (look it up on the map and you will see what I mean)stop in if you are in the neighborhood!dilatush(at)amigo.net>>________________________________________________________________________________Date: Sun, 2 Dec 2001 11:17:41 -0800Subject: Pietenpol-List: Updated Email List Photo Share Available!
Dear Oscar,Thanks for your comments to my remarks about the weights of Pietenpols.When I started my Piet, (about 6 years ago), I too had the vision of makingthe lightest possible airframe, strictly according to the original plans.But of course my situation was a little different than Bernie's Pietenpol.First, I live at over 7,000' in a valley surrounded by mountains on the westof over 14,000' (the continental divide) and on the north and east of over11,000'. The only way down is to go down the Arkansas Valley south and thensoutheast. So of course, I needed more power than a Model A engine wouldput out at this altitude;Second, contemporary airports that I fly into have a lot of concrete so Ineed brakes, to keep from running into that Gulfstream on the ramp. Mayberun under it? And of course a steerable tailwheel to try and remainstraight during rollout on landing.Third, the FAA requires a ELT and this requires the unit, batteries, wiring,mounting bracket etc.Fourth, due to building space and transportation limitations, gotta go withthe three piece wing.And it goes on and on, get the picture?So I decided to use an EA82 turbocharged and fuel injected engine to get offthe ground here and over the 14,000' mountains in case I decide to go toUtah. But this requires a prop reduction unit, however no one has made onefor this particular version of a Subaru engine. Now I got to design andmake one. Opps -- I can't afford to have the sprockets made out ofaluminum, better go with the stock steel one. Ouch! 70 pounds added to theengine. Oh well, the Piet is known as a tail heavy design anyway, it willnot be a problem. Now everyone knows that it is dangerous to hand start ageared engine, need a starter now, better also get the alternator to keepthe battery charged. Holy Moses, I forgot that the fuel burn will be higherand range reduced, better plan on another fuel tank too!So you see, Oscar, that it is a little like eating peanuts, you just can'tstop at one.Realizing that things were getting out of hand, I made up a simplespreadsheet program to keep track of weights and weight and balancethroughout the construction, and carefully weighed each component before andduring installation. Those that I didn't have on hand were estimated--howmany square feet of aluminum will I use for the cowl, etc.In spite of my best efforts, my empty weight has come out at 790 pounds.The saving grace is that the plane will have about the same performance as asuper cub. I calculated the rate of climb at 9,000' to be better than 1200ft/min. at gross and the center of gravity is at within limits.Now the point that I'm making is that in spite of our best efforts, we willend up building the Pietenpol to fit our own needs and the contemporaryflight environment with which we have to live. If weight is added to meetthese conditions, then we must look at the strength of the entire machineto be safe. Not only struts, and wing fittings, but landing gear, seats,tailwheel assembly and so on. I don't think that it is possible to count onwhat has been done in the past as a reliable indicator of the future.Cordially,John Dilatush, NX114D, only have the prop to go, now making a duplicator touse a great pattern I got from Duane Woolsey.I am in Salida Colorado (look it up on the map and you will see what I mean)stop in if you are in the neighborhood!dilatush(at)amigo.net>>________________________________________________________________________________Date: Sun, 2 Dec 2001 11:17:41 -0800Subject: Pietenpol-List: Updated Email List Photo Share Available!