Original Posted By: Michael D Cuy
Subject: Pietenpol-List: Direct Drive Subaru>Since it is so quiet on the list, I have to comment on the concept ofdirect>drive and a small engine on a pietenpol.>I ran the numbers on a Model A engine vs. an 1800 cc Subaru and,suprisingly,>they are fairly close.>I used the formula of RPM x torque / 5252 and some assumptions (I know what>assumptions are). I then took the data and applied it to Eric Clutton'sbook>"Propellor Making For the Amateur". He has some nomagraphs in his book that>appear to be fairly accurate. If any of you are thinking of carving yourown>prop, get this book.>>At last count, I have carved 6 different props and found that this book is>really worth its weight in spruce - er uh gold. (I currently have 630 hourson>one I carved for my RV6)>>If one assumes the Subaru will be turning 2700 RPM with a 74 inch prop at80>MPH the setup is 73% efficient (not real great but it works). The setup>delivers 41.2 useable horsepower as thrust.>>If one assumes a Model A is turning 1800 RPM with an 80 inch prop at 80MPH,>the setup is 80% efficient. It is delivering 36.0 useable horsepower asthrust.>>The nomagraphs do not lend themselves to lower speeds encountered in climbon>a Piet. My experience says that the bigger the prop and slower, the betterthe>climb. I suspect it would be a close race between the two setups in climb.I'd>put my money on the A.>>As far as the crankshaft holding up, I am aware of several direct drive>gyrocopters running Subarus successfully. It seems to be a bulletproofengine.>In a Piet, it will have 2 main drawbacks. Thrust at low speed will besuspect>and it will generate a lot more prop noise.>>I really like the idea of being able to use a cheap engine to go flying. Ido>not know what I will use yet, but it will probably be like a Subaru. Just>remember, when the FAA makes you put "EXPERIMENTAL" in these things, itsfor a>reason.>>Bob Seibert>RV6 N691RV>Pietenpol Almost On the Gear>________________________________________________________________________________
Pietenpol-List: Direct Drive Subaru
Pietenpol-List: Direct Drive Subaru
Original Posted By: John Greenlee
Since it is so quiet on the list, I have to comment on the concept of directdrive and a small engine on a pietenpol.I ran the numbers on a Model A engine vs. an 1800 cc Subaru and, suprisingly,they are fairly close.I used the formula of RPM x torque / 5252 and some assumptions (I know whatassumptions are). I then took the data and applied it to Eric Clutton's book"Propellor Making For the Amateur". He has some nomagraphs in his book thatappear to be fairly accurate. If any of you are thinking of carving your ownprop, get this book. At last count, I have carved 6 different props and found that this book isreally worth its weight in spruce - er uh gold. (I currently have 630 hours onone I carved for my RV6)If one assumes the Subaru will be turning 2700 RPM with a 74 inch prop at 80MPH the setup is 73% efficient (not real great but it works). The setupdelivers 41.2 useable horsepower as thrust.If one assumes a Model A is turning 1800 RPM with an 80 inch prop at 80 MPH,the setup is 80% efficient. It is delivering 36.0 useable horsepower as thrust.The nomagraphs do not lend themselves to lower speeds encountered in climb ona Piet. My experience says that the bigger the prop and slower, the better theclimb. I suspect it would be a close race between the two setups in climb. I'dput my money on the A.As far as the crankshaft holding up, I am aware of several direct drivegyrocopters running Subarus successfully. It seems to be a bulletproof engine.In a Piet, it will have 2 main drawbacks. Thrust at low speed will be suspectand it will generate a lot more prop noise. I really like the idea of being able to use a cheap engine to go flying. I donot know what I will use yet, but it will probably be like a Subaru. Justremember, when the FAA makes you put "EXPERIMENTAL" in these things, its for areason. Bob SeibertRV6 N691RVPietenpol Almost On the Gear________________________________________________________________________________
Since it is so quiet on the list, I have to comment on the concept of directdrive and a small engine on a pietenpol.I ran the numbers on a Model A engine vs. an 1800 cc Subaru and, suprisingly,they are fairly close.I used the formula of RPM x torque / 5252 and some assumptions (I know whatassumptions are). I then took the data and applied it to Eric Clutton's book"Propellor Making For the Amateur". He has some nomagraphs in his book thatappear to be fairly accurate. If any of you are thinking of carving your ownprop, get this book. At last count, I have carved 6 different props and found that this book isreally worth its weight in spruce - er uh gold. (I currently have 630 hours onone I carved for my RV6)If one assumes the Subaru will be turning 2700 RPM with a 74 inch prop at 80MPH the setup is 73% efficient (not real great but it works). The setupdelivers 41.2 useable horsepower as thrust.If one assumes a Model A is turning 1800 RPM with an 80 inch prop at 80 MPH,the setup is 80% efficient. It is delivering 36.0 useable horsepower as thrust.The nomagraphs do not lend themselves to lower speeds encountered in climb ona Piet. My experience says that the bigger the prop and slower, the better theclimb. I suspect it would be a close race between the two setups in climb. I'dput my money on the A.As far as the crankshaft holding up, I am aware of several direct drivegyrocopters running Subarus successfully. It seems to be a bulletproof engine.In a Piet, it will have 2 main drawbacks. Thrust at low speed will be suspectand it will generate a lot more prop noise. I really like the idea of being able to use a cheap engine to go flying. I donot know what I will use yet, but it will probably be like a Subaru. Justremember, when the FAA makes you put "EXPERIMENTAL" in these things, its for areason. Bob SeibertRV6 N691RVPietenpol Almost On the Gear________________________________________________________________________________
Pietenpol-List: Re: Direct Drive Subaru
Original Posted By: Seibert
How does the weight of the direct drive Subaru compare to the heavy A?It might work out o.k. ( I'd be interested in knowing how you come out.) Iwonder if you would run into problems getting the ship up to flying speed.The Corvair has a similar difficulty i.e. high RPM on the draggy slow oldairframe, but overcomes simply because it has a lot of power to spare. Myunderstanding is the A works because the power it does make is all in theslower RPM ranges, in other words more usable on a draggy airframe. I thinkthe 80mph assumption is a little optimistic. How do the numbers work at65mph?I've read that the WWI fighters (draggier even than a Piet) had engines thatmade their power at 1500rpm or maybe even less.Interested in your project.John-----Original Message-----
How does the weight of the direct drive Subaru compare to the heavy A?It might work out o.k. ( I'd be interested in knowing how you come out.) Iwonder if you would run into problems getting the ship up to flying speed.The Corvair has a similar difficulty i.e. high RPM on the draggy slow oldairframe, but overcomes simply because it has a lot of power to spare. Myunderstanding is the A works because the power it does make is all in theslower RPM ranges, in other words more usable on a draggy airframe. I thinkthe 80mph assumption is a little optimistic. How do the numbers work at65mph?I've read that the WWI fighters (draggier even than a Piet) had engines thatmade their power at 1500rpm or maybe even less.Interested in your project.John-----Original Message-----
Pietenpol-List: Re: Direct Drive Subaru
Original Posted By: Phil Peck
Hello to the group, In my travels today I happened by the auto dealership anddiscovered the hood open for display of the recent Subaru Legacy models..Of course the salesman did not have explicit technical information, but Igleaned a little from the short visit.. The newest model Subarus use an EJ22 which is SOHC 2.2 liter 130hpand the EJ25 DOHC 2.5 liter which is 160hp. I didn't bother to ask about turbos and neat stuff like that. Base price model with smaller of the two engines was 20k and"Outback" models with the larger 2500cc DOHC engine started at about 2kmore.. Low mileage units are most likely already available in the salvageyards, but I haven't checked on an engine price yet.RichOn Sun, 21 Jun 1998, Seibert wrote:> Since it is so quiet on the list, I have to comment on the concept of direct> drive and a small engine on a pietenpol.> I ran the numbers on a Model A engine vs. an 1800 cc Subaru and, suprisingly,> they are fairly close.> I used the formula of RPM x torque / 5252 and some assumptions (I know what> assumptions are). I then took the data and applied it to Eric Clutton's book> "Propellor Making For the Amateur". He has some nomagraphs in his book that> appear to be fairly accurate. If any of you are thinking of carving your own> prop, get this book. > > At last count, I have carved 6 different props and found that this book is> really worth its weight in spruce - er uh gold. (I currently have 630 hours on> one I carved for my RV6)> > If one assumes the Subaru will be turning 2700 RPM with a 74 inch prop at 80> MPH the setup is 73% efficient (not real great but it works). The setup> delivers 41.2 useable horsepower as thrust.> > If one assumes a Model A is turning 1800 RPM with an 80 inch prop at 80 MPH,> the setup is 80% efficient. It is delivering 36.0 useable horsepower as thrust.> > The nomagraphs do not lend themselves to lower speeds encountered in climb on> a Piet. My experience says that the bigger the prop and slower, the better the> climb. I suspect it would be a close race between the two setups in climb. I'd> put my money on the A.> > As far as the crankshaft holding up, I am aware of several direct drive> gyrocopters running Subarus successfully. It seems to be a bulletproof engine.> In a Piet, it will have 2 main drawbacks. Thrust at low speed will be suspect> and it will generate a lot more prop noise. > > I really like the idea of being able to use a cheap engine to go flying. I do> not know what I will use yet, but it will probably be like a Subaru. Just> remember, when the FAA makes you put "EXPERIMENTAL" in these things, its fora> reason. > > Bob Seibert> RV6 N691RV> Pietenpol Almost On the Gear> > ________________________________________________________________________________
Hello to the group, In my travels today I happened by the auto dealership anddiscovered the hood open for display of the recent Subaru Legacy models..Of course the salesman did not have explicit technical information, but Igleaned a little from the short visit.. The newest model Subarus use an EJ22 which is SOHC 2.2 liter 130hpand the EJ25 DOHC 2.5 liter which is 160hp. I didn't bother to ask about turbos and neat stuff like that. Base price model with smaller of the two engines was 20k and"Outback" models with the larger 2500cc DOHC engine started at about 2kmore.. Low mileage units are most likely already available in the salvageyards, but I haven't checked on an engine price yet.RichOn Sun, 21 Jun 1998, Seibert wrote:> Since it is so quiet on the list, I have to comment on the concept of direct> drive and a small engine on a pietenpol.> I ran the numbers on a Model A engine vs. an 1800 cc Subaru and, suprisingly,> they are fairly close.> I used the formula of RPM x torque / 5252 and some assumptions (I know what> assumptions are). I then took the data and applied it to Eric Clutton's book> "Propellor Making For the Amateur". He has some nomagraphs in his book that> appear to be fairly accurate. If any of you are thinking of carving your own> prop, get this book. > > At last count, I have carved 6 different props and found that this book is> really worth its weight in spruce - er uh gold. (I currently have 630 hours on> one I carved for my RV6)> > If one assumes the Subaru will be turning 2700 RPM with a 74 inch prop at 80> MPH the setup is 73% efficient (not real great but it works). The setup> delivers 41.2 useable horsepower as thrust.> > If one assumes a Model A is turning 1800 RPM with an 80 inch prop at 80 MPH,> the setup is 80% efficient. It is delivering 36.0 useable horsepower as thrust.> > The nomagraphs do not lend themselves to lower speeds encountered in climb on> a Piet. My experience says that the bigger the prop and slower, the better the> climb. I suspect it would be a close race between the two setups in climb. I'd> put my money on the A.> > As far as the crankshaft holding up, I am aware of several direct drive> gyrocopters running Subarus successfully. It seems to be a bulletproof engine.> In a Piet, it will have 2 main drawbacks. Thrust at low speed will be suspect> and it will generate a lot more prop noise. > > I really like the idea of being able to use a cheap engine to go flying. I do> not know what I will use yet, but it will probably be like a Subaru. Just> remember, when the FAA makes you put "EXPERIMENTAL" in these things, its fora> reason. > > Bob Seibert> RV6 N691RV> Pietenpol Almost On the Gear> > ________________________________________________________________________________
Pietenpol-List: Re: Direct Drive Subaru
Original Posted By: PTNPOL(at)aol.com
>Hello to the group,>> In my travels today I happened by the auto dealership and>discovered the hood open for display of the recent Subaru Legacymodels..>Of course the salesman did not have explicit technical information, butI>gleaned a little from the short visit..> The newest model Subarus use an EJ22 which is SOHC 2.2 liter 130hp>and the EJ25 DOHC 2.5 liter which is 160hp.> I didn't bother to ask about turbos and neat stuff like that.> Base price model with smaller of the two engines was 20k and>"Outback" models with the larger 2500cc DOHC engine started at about 2k>more.. > Low mileage units are most likely already available in the salvage>yards, but I haven't checked on an engine price yet.>Rich>Reiner Hoffman recommends against running the EJ series direct drive.According to him, the crank is not as robust as the EA series crank.Glenn________________________________________________________________________________
>Hello to the group,>> In my travels today I happened by the auto dealership and>discovered the hood open for display of the recent Subaru Legacymodels..>Of course the salesman did not have explicit technical information, butI>gleaned a little from the short visit..> The newest model Subarus use an EJ22 which is SOHC 2.2 liter 130hp>and the EJ25 DOHC 2.5 liter which is 160hp.> I didn't bother to ask about turbos and neat stuff like that.> Base price model with smaller of the two engines was 20k and>"Outback" models with the larger 2500cc DOHC engine started at about 2k>more.. > Low mileage units are most likely already available in the salvage>yards, but I haven't checked on an engine price yet.>Rich>Reiner Hoffman recommends against running the EJ series direct drive.According to him, the crank is not as robust as the EA series crank.Glenn________________________________________________________________________________