OS140RX Versus OS140RX-FI
09-24-2004, 11:21 PM
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OS140RX Versus OS140RX-FI
Just a question to help in my, way into the future, planning for a 2m model.
Which of the two above engines would you go for if the obvious price difference were not an issue ?
Which of the two above engines would you go for if the obvious price difference were not an issue ?
09-25-2004, 07:56 AM
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RE: OS140RX Versus OS140RX-FI
I have the OS 140 EFI. This engine has a wonderfull throttle response and is very linear. It is very easy to set up. Just locate your fuel tank over the CG and hook up the electronic module. I have only flow a club member's plane with the OS 140 Rx. Both engines have the same power. If you tend to fly a full throttle, go for the less expensive Rx. For some of the current maneuvers in Masters or FAI, the slightly more linear throttle may be an advantage. The only negative side of the EFI engine is that the fuel injection valve sticks shut if my plane sets up over two weeks. Then I have to turn the plane over and prime the engine with some fuel in the throttle barrel. After it starts, it runs well.
If I had to do it over again, I would save the money and buy the OS 140 Rx. (I fly Masters, but tend to fly at warp speed).
Steve
If I had to do it over again, I would save the money and buy the OS 140 Rx. (I fly Masters, but tend to fly at warp speed).
Steve
09-25-2004, 08:18 AM
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RE: OS140RX Versus OS140RX-FI
I have observed several of BOTH the EFI and RX. Nearly ALL of the EFI owners have said what Ron did - "buy more servos or airplanes, get the RX". ONE injector problem at a contest, and you're DEAD.
Just get an RX, remove the stock bearing - throw it as far as you can into the nearest slime pond - and replace it with the Stainless EFI bearing (same size, etc.) or other providers of these like AFC bearings, Boca Bearings, etc.
The "linearity" issue is a NON issue when tuned to a soft boost pipe, and properly loading the motor torque curve with the prop that works best for your airframe.
Or - save MORE money - and go get an OS 1.60 setup....
... and enjoy even MORE power, and less fuss.
Just get an RX, remove the stock bearing - throw it as far as you can into the nearest slime pond - and replace it with the Stainless EFI bearing (same size, etc.) or other providers of these like AFC bearings, Boca Bearings, etc.
The "linearity" issue is a NON issue when tuned to a soft boost pipe, and properly loading the motor torque curve with the prop that works best for your airframe.
Or - save MORE money - and go get an OS 1.60 setup....
... and enjoy even MORE power, and less fuss.
09-25-2004, 09:28 AM
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RE: OS140RX Versus OS140RX-FI
The 1.40 EFI is by far the easiest to operate. The in-flight tuning capability can be a life saver when the climatic conditions change. I am also a big fan of the 1.40 RX. We go way back to a time when everyone was flying a 4-c. (around 1997 I think). It is great to now see the 2-c's doing so well.
The true weakness of the FI is the injector if you ignore the instructions and use a soft-mount. There are two parts in the injector that get worn, very quickly, when a "soft" mount is used. By "soft" I mean ones like the ARI's etc. If you use an "A" mount the injetor lasts at least 600 flights. I recently tested some soft mounts using the injector and two of them went bad in approx. 30 flights each.
My buddy in SC, Earl Vincent, diagnosed the problem years ago. There is a plunger, much like that in a YS reglator. This brass plunger fits into an aluminum part with a sliicone sealing ring. The hole that the plunger goes into will wear out very quickly if the engine bounces too much. A stiiffer, but still an iso, mount does not have this affect. I machined new parts that were a press fit and the repaired injectors all now run reliably. I have not run them again on the "soft" mounts.
The "sticking" may well be the fuel that is being used. It is a very good idea to flush the injector with alcohol. There is an air (Atmosphere) hole in the square spring adjuster that should be checked for junk. This can be adjusted by screwing it in inwards to let fuel get through easier on first starts etc. (A 1/16 ata time is about right. The module can handle changes in the injector.
The true weakness of the RX is that it will "bog down" , on occasion. Usually on the take off run. Usually at the NAT's :-) It performs best with the OS 1.40 pipe but must be "on-tune" to be 100% all the way through the range. When it gets colder, around 60F, the RX can become baulky in long down -ine transitions etc. The EFI allows you to adjust this in the air or on the ground . The RX rarely quits but it takes a while to clear its throat when cold or rich.
The best combo is the RX with an OS mix carb. These carbs are, unfortubately, very hard to find. OS don't seem to want to make them - propably because it could/would affect the 1.40 EFI sales. Similarly I think that this is why we don't see an oS 1.60 RX.
Regards,
Eric.
The true weakness of the FI is the injector if you ignore the instructions and use a soft-mount. There are two parts in the injector that get worn, very quickly, when a "soft" mount is used. By "soft" I mean ones like the ARI's etc. If you use an "A" mount the injetor lasts at least 600 flights. I recently tested some soft mounts using the injector and two of them went bad in approx. 30 flights each.
My buddy in SC, Earl Vincent, diagnosed the problem years ago. There is a plunger, much like that in a YS reglator. This brass plunger fits into an aluminum part with a sliicone sealing ring. The hole that the plunger goes into will wear out very quickly if the engine bounces too much. A stiiffer, but still an iso, mount does not have this affect. I machined new parts that were a press fit and the repaired injectors all now run reliably. I have not run them again on the "soft" mounts.
The "sticking" may well be the fuel that is being used. It is a very good idea to flush the injector with alcohol. There is an air (Atmosphere) hole in the square spring adjuster that should be checked for junk. This can be adjusted by screwing it in inwards to let fuel get through easier on first starts etc. (A 1/16 ata time is about right. The module can handle changes in the injector.
The true weakness of the RX is that it will "bog down" , on occasion. Usually on the take off run. Usually at the NAT's :-) It performs best with the OS 1.40 pipe but must be "on-tune" to be 100% all the way through the range. When it gets colder, around 60F, the RX can become baulky in long down -ine transitions etc. The EFI allows you to adjust this in the air or on the ground . The RX rarely quits but it takes a while to clear its throat when cold or rich.
The best combo is the RX with an OS mix carb. These carbs are, unfortubately, very hard to find. OS don't seem to want to make them - propably because it could/would affect the 1.40 EFI sales. Similarly I think that this is why we don't see an oS 1.60 RX.
Regards,
Eric.
09-25-2004, 10:38 AM
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RE: OS140RX Versus OS140RX-FI
Hello Eric and Bob, I am using the 140 RX with the OS pipe and OS header, turning APC 17 *12 but only get 7200 rpm with 10 % nitro and 16 -18% oil. with a "pastorello" soft mount, 3 inches diameter with two rubber layer (innertube motorcycle) I think the engine bounces too much with this mount but it is quiet.
Do you know any set-up: pipe-header long, Prop, mount and so on in order to get more power for my 10.5 lb Larimar?
I put the pipe 5 mm from the header, like the OS manual said.
Thanks for your help.
Jorge
Do you know any set-up: pipe-header long, Prop, mount and so on in order to get more power for my 10.5 lb Larimar?
I put the pipe 5 mm from the header, like the OS manual said.
Thanks for your help.
Jorge
09-25-2004, 12:35 PM
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RE: OS140RX Versus OS140RX-FI
Others with 1.40's need to respond credibly; it sounds like the setup is a little lower than what I've heard from others. Most folks with the setup you're stating say 8100 or more...a lot of variables go into that, mainly the sharpness of the tuning. You probably should have a tuning length of 23" plus, following the header, measured from the plug straight to the reflecting baffle. Probably more around 23.5" or so should be around 81-8200 rpm. You may also need to go to 15%, although many have said there is little difference on the 1.40.
All of what I wrote is NOT personal experience. I have only run the OS 1.60 FX and Mintor 1.70 (plus the ST 2300)....
All of what I wrote is NOT personal experience. I have only run the OS 1.60 FX and Mintor 1.70 (plus the ST 2300)....
09-27-2004, 02:47 AM
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RE: OS140RX Versus OS140RX-FI
i suggest the 140 RX (no pump) because its already powerful enough to hover a pattern plane( but with high throws) at 3/4 throttle and it consumes less fuel
09-27-2004, 08:04 AM
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RE: OS140RX Versus OS140RX-FI
Eric,
Have you seen the remote needle that OS sells for the 1.40RX with the 70A carb? The link is http://www2.towerhobbies.com/cgi-bin...?&I=LXCN51&P=Z
Would this do the same thing as the mixture control carb? While this would appear to adjust the main needle, not the idle mixture, it would appear that you could set up a mixture curve using it tied into your throttle curve.
Not a 140 owner, but I saw this sometime back and wondered about it.
Jon Lowe
PS, I will be at the Don Lowe Masters (for obvious reasons!), and would like to have the chance to meet and talk with you. I will be around my parents motorhome near the gazebo. Maybe we can link up there.
Have you seen the remote needle that OS sells for the 1.40RX with the 70A carb? The link is http://www2.towerhobbies.com/cgi-bin...?&I=LXCN51&P=Z
Would this do the same thing as the mixture control carb? While this would appear to adjust the main needle, not the idle mixture, it would appear that you could set up a mixture curve using it tied into your throttle curve.
Not a 140 owner, but I saw this sometime back and wondered about it.
Jon Lowe
PS, I will be at the Don Lowe Masters (for obvious reasons!), and would like to have the chance to meet and talk with you. I will be around my parents motorhome near the gazebo. Maybe we can link up there.
ORIGINAL: Eric.Henderson
The 1.40 EFI is by far the easiest to operate. The in-flight tuning capability can be a life saver when the climatic conditions change. I am also a big fan of the 1.40 RX. We go way back to a time when everyone was flying a 4-c. (around 1997 I think). It is great to now see the 2-c's doing so well.
The true weakness of the FI is the injector if you ignore the instructions and use a soft-mount. There are two parts in the injector that get worn, very quickly, when a "soft" mount is used. By "soft" I mean ones like the ARI's etc. If you use an "A" mount the injetor lasts at least 600 flights. I recently tested some soft mounts using the injector and two of them went bad in approx. 30 flights each.
My buddy in SC, Earl Vincent, diagnosed the problem years ago. There is a plunger, much like that in a YS reglator. This brass plunger fits into an aluminum part with a sliicone sealing ring. The hole that the plunger goes into will wear out very quickly if the engine bounces too much. A stiiffer, but still an iso, mount does not have this affect. I machined new parts that were a press fit and the repaired injectors all now run reliably. I have not run them again on the "soft" mounts.
The "sticking" may well be the fuel that is being used. It is a very good idea to flush the injector with alcohol. There is an air (Atmosphere) hole in the square spring adjuster that should be checked for junk. This can be adjusted by screwing it in inwards to let fuel get through easier on first starts etc. (A 1/16 ata time is about right. The module can handle changes in the injector.
The true weakness of the RX is that it will "bog down" , on occasion. Usually on the take off run. Usually at the NAT's :-) It performs best with the OS 1.40 pipe but must be "on-tune" to be 100% all the way through the range. When it gets colder, around 60F, the RX can become baulky in long down -ine transitions etc. The EFI allows you to adjust this in the air or on the ground . The RX rarely quits but it takes a while to clear its throat when cold or rich.
The best combo is the RX with an OS mix carb. These carbs are, unfortubately, very hard to find. OS don't seem to want to make them - propably because it could/would affect the 1.40 EFI sales. Similarly I think that this is why we don't see an oS 1.60 RX.
Regards,
Eric.
The 1.40 EFI is by far the easiest to operate. The in-flight tuning capability can be a life saver when the climatic conditions change. I am also a big fan of the 1.40 RX. We go way back to a time when everyone was flying a 4-c. (around 1997 I think). It is great to now see the 2-c's doing so well.
The true weakness of the FI is the injector if you ignore the instructions and use a soft-mount. There are two parts in the injector that get worn, very quickly, when a "soft" mount is used. By "soft" I mean ones like the ARI's etc. If you use an "A" mount the injetor lasts at least 600 flights. I recently tested some soft mounts using the injector and two of them went bad in approx. 30 flights each.
My buddy in SC, Earl Vincent, diagnosed the problem years ago. There is a plunger, much like that in a YS reglator. This brass plunger fits into an aluminum part with a sliicone sealing ring. The hole that the plunger goes into will wear out very quickly if the engine bounces too much. A stiiffer, but still an iso, mount does not have this affect. I machined new parts that were a press fit and the repaired injectors all now run reliably. I have not run them again on the "soft" mounts.
The "sticking" may well be the fuel that is being used. It is a very good idea to flush the injector with alcohol. There is an air (Atmosphere) hole in the square spring adjuster that should be checked for junk. This can be adjusted by screwing it in inwards to let fuel get through easier on first starts etc. (A 1/16 ata time is about right. The module can handle changes in the injector.
The true weakness of the RX is that it will "bog down" , on occasion. Usually on the take off run. Usually at the NAT's :-) It performs best with the OS 1.40 pipe but must be "on-tune" to be 100% all the way through the range. When it gets colder, around 60F, the RX can become baulky in long down -ine transitions etc. The EFI allows you to adjust this in the air or on the ground . The RX rarely quits but it takes a while to clear its throat when cold or rich.
The best combo is the RX with an OS mix carb. These carbs are, unfortubately, very hard to find. OS don't seem to want to make them - propably because it could/would affect the 1.40 EFI sales. Similarly I think that this is why we don't see an oS 1.60 RX.
Regards,
Eric.
09-27-2004, 08:18 AM
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RE: OS140RX Versus OS140RX-FI
Jon,
I have thought about the sewrvo driven remote needle concept a lot. I used to use them when breaking in the more fickle .61's. Then remov the servo once the engine was reliable.
First of all, the arm of the mixture conrol moves ALL of the time. It does this in concert with the air-valve arm.
There is no delay in the mixture setting. A needle may of may not do the job as quickly. I did notice some latency in the older systems (above). I also worry that the threads will wear or it will become too stiff.
This is, of course, is only theory. So the only way to know is to try it! :-)
Would love to hook up. I hope to have some "wander around" time because there will be two separate judges panels.
Regards,
Eric.
I have thought about the sewrvo driven remote needle concept a lot. I used to use them when breaking in the more fickle .61's. Then remov the servo once the engine was reliable.
First of all, the arm of the mixture conrol moves ALL of the time. It does this in concert with the air-valve arm.
There is no delay in the mixture setting. A needle may of may not do the job as quickly. I did notice some latency in the older systems (above). I also worry that the threads will wear or it will become too stiff.
This is, of course, is only theory. So the only way to know is to try it! :-)
Would love to hook up. I hope to have some "wander around" time because there will be two separate judges panels.
Regards,
Eric.
