Original Posted By: "David B. Schober"
ILately I have been looking over the piet web page , and there is a fellow therewho has been getting 67 hp from the ford model B engine, with some 150 ft poundsof torque....(low compression to save rods&bearings, and improved carboratorfor breathing, along with big valves)at an rpm of 2200... A long time ago I read that the new high rev engines were obtaining their powerfrom rpm, when the real measure of an aircraft's power was in torque.Question, does anybody understand torque vs horsepower? I would sure be interested in the simple ford engine, over the modern types, ifI knew that it would provide the necessary output.http://www.mailexcite.com________________________________________________________________________________
Pietenpol-List: torque vs horsepower
Pietenpol-List: Re: torque vs horsepower
Original Posted By: "McNarry, John"
Horse power can be obtained by the equationhp=(torque*RPM)/5252Since horse power is a function of both torque and rpm, if you increase eitherthe hp will increase. You don't get something for nothing however. Prop efficiencydrops off as the rpm increases. The traditional way of thinking is go witha long stroke, low rpm, high torque engine if you want yourairplane to perform. How do you think a Curtiss JN-4 flew on only 90 hp. The otherthing to consider is cubic inches. If you ever compared the performance ofa J3C65, J3L65 and J3F65 you would understand the advantage of cubes. All threeengines have the same 65 horse power rating but usingdifferent combinations of torque and rpm. The Franklin has the smallest displacement,followed by the Lycoming, then the Continental. The Franklin runs the smoothestthen the Lyc then the Cont. but the Continental outperformes the othershands down.I've flown Piets with Fords, Corvairs and Continental A-65s. Of all, the Ford isthe most fun and has performance that is more than adequate for your averageSunday afternoon flying and prices are still reasonable. I didn't care for theCorvair overly but it was OK. The A65 performance was onlyslightly better than the Ford.If you are building a Piet, make your engine choice based on what you have available.The only performance peramiter that changes is takeoff and climb. Cruisewill be about the same no matter what engine you use. The cost to convert modernauto engines far exceedes the cost of the Model A and won'tgive you any better performance with only marginal reliability improvements. Whenyou look at the type of flying that you will do in a Piet, the overhaul intervalis insignificant. If you figure a Ford should be overhauled at 400-500 hours,and you fly 25 -50 hours a year (that's a lot of flyingfor a Piet), you should expect 10 years or more of flying before needing to teardown the engine.oil can wrote:> I>> Lately I have been looking over the piet web page , and there is a fellow therewho has been getting 67 hp from the ford model B engine, with some 150 ft poundsof torque....(low compression to save rods&bearings, and improved carboratorfor breathing, along with big valves)at an rpm of 2200...>> A long time ago I read that the new high rev engines were obtaining their powerfrom rpm, when the real measure of an aircraft's power was in torque.>> Question, does anybody understand torque vs horsepower?>> I would sure be interested in the simple ford engine, over the modern types,if I knew that it would provide the necessary output.>> http://www.mailexcite.com--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education CenterRt. 3 Box 13Bridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________
Horse power can be obtained by the equationhp=(torque*RPM)/5252Since horse power is a function of both torque and rpm, if you increase eitherthe hp will increase. You don't get something for nothing however. Prop efficiencydrops off as the rpm increases. The traditional way of thinking is go witha long stroke, low rpm, high torque engine if you want yourairplane to perform. How do you think a Curtiss JN-4 flew on only 90 hp. The otherthing to consider is cubic inches. If you ever compared the performance ofa J3C65, J3L65 and J3F65 you would understand the advantage of cubes. All threeengines have the same 65 horse power rating but usingdifferent combinations of torque and rpm. The Franklin has the smallest displacement,followed by the Lycoming, then the Continental. The Franklin runs the smoothestthen the Lyc then the Cont. but the Continental outperformes the othershands down.I've flown Piets with Fords, Corvairs and Continental A-65s. Of all, the Ford isthe most fun and has performance that is more than adequate for your averageSunday afternoon flying and prices are still reasonable. I didn't care for theCorvair overly but it was OK. The A65 performance was onlyslightly better than the Ford.If you are building a Piet, make your engine choice based on what you have available.The only performance peramiter that changes is takeoff and climb. Cruisewill be about the same no matter what engine you use. The cost to convert modernauto engines far exceedes the cost of the Model A and won'tgive you any better performance with only marginal reliability improvements. Whenyou look at the type of flying that you will do in a Piet, the overhaul intervalis insignificant. If you figure a Ford should be overhauled at 400-500 hours,and you fly 25 -50 hours a year (that's a lot of flyingfor a Piet), you should expect 10 years or more of flying before needing to teardown the engine.oil can wrote:> I>> Lately I have been looking over the piet web page , and there is a fellow therewho has been getting 67 hp from the ford model B engine, with some 150 ft poundsof torque....(low compression to save rods&bearings, and improved carboratorfor breathing, along with big valves)at an rpm of 2200...>> A long time ago I read that the new high rev engines were obtaining their powerfrom rpm, when the real measure of an aircraft's power was in torque.>> Question, does anybody understand torque vs horsepower?>> I would sure be interested in the simple ford engine, over the modern types,if I knew that it would provide the necessary output.>> http://www.mailexcite.com--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education CenterRt. 3 Box 13Bridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________
Pietenpol-List: RE: torque vs horsepower
Original Posted By: Alan Swanson
John,Quit you braggin. I want a ride. :)Steve E.--Hi David I agree whole heartedly with your statements. I like the quietness of thelargeprops at a relatively slow speed. I really enjoyed the ride I had in a Fordpowered piet. It seemed to fly every bit as well as the Continental powerhowever I think the take off run was longer.I started building a B for my aircraft untill I lucked into a 1927 deHavillandCirrus engine. The Ford sort of lost its charm and I think I fell in lovewith theCirrus! |:-)John Mc________________________________________________________________________________
John,Quit you braggin. I want a ride. :)Steve E.--Hi David I agree whole heartedly with your statements. I like the quietness of thelargeprops at a relatively slow speed. I really enjoyed the ride I had in a Fordpowered piet. It seemed to fly every bit as well as the Continental powerhowever I think the take off run was longer.I started building a B for my aircraft untill I lucked into a 1927 deHavillandCirrus engine. The Ford sort of lost its charm and I think I fell in lovewith theCirrus! |:-)John Mc________________________________________________________________________________
Pietenpol-List: Re: torque vs horsepower
Original Posted By: steve(at)byu.edu
Hi David I agree whole heartedly with your statements. I like the quietness of the largeprops at a relatively slow speed. I really enjoyed the ride I had in a Ford powered piet. It seemed to fly every bit as well as the Continental power however I think the take off run was longer.I started building a B for my aircraft untill I lucked into a 1927 de HavillandCirrus engine. The Ford sort of lost its charm and I think I fell in love withthe Cirrus! |:-)John Mc________________________________________________________________________________
Hi David I agree whole heartedly with your statements. I like the quietness of the largeprops at a relatively slow speed. I really enjoyed the ride I had in a Ford powered piet. It seemed to fly every bit as well as the Continental power however I think the take off run was longer.I started building a B for my aircraft untill I lucked into a 1927 de HavillandCirrus engine. The Ford sort of lost its charm and I think I fell in love withthe Cirrus! |:-)John Mc________________________________________________________________________________
Pietenpol-List: RE: torque vs horsepower
Original Posted By: oil can
________________________________________________________________________________Send reply to: Pietenpol Discussion John,Quit you braggin. I want a ride. :)Steve E.If I ever get this thing done! You Bet! I dream of flying it to Brodhead..... Letssee now, if I quit work today and work 12 hour days could I get there next summer?John Mc________________________________________________________________________________
________________________________________________________________________________Send reply to: Pietenpol Discussion John,Quit you braggin. I want a ride. :)Steve E.If I ever get this thing done! You Bet! I dream of flying it to Brodhead..... Letssee now, if I quit work today and work 12 hour days could I get there next summer?John Mc________________________________________________________________________________