Saito FG-60R3
01-02-2017, 12:20 PM
#1176
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Happy New Year everyone... The question was if I ever had cylinder three let go and the answer is yes... twice...
The first failure for that cylinder happened on the stand during break-in... 15:1 87octane and Amzoil... third or fourth 16oz tank.. it had been running for about 5 minutes at approx. 4,000RPM-full throttle (breakin needles). the second time it failed was at GunSmoke Scale Master qualifier in Mesa, AZ... Normal flight round 3 or 4 maneuvers in... 1/2 throttle, level flight, top cylinder temp approx. 185 degrees... I immediately landed and my caller had a digital infrared pyrometer (my Wulf has awesome ducting in the cowl - over the cylinders and negative-pressure vents below). I've never had this motor (either of the ones I own) at 6600RPM static... I typically have it needled at 6400RPM on a Xoar 22X10 (digital tac on the ignition box).
I've been using the Keleo exhaust for this motor after the motor is broken in... I'm always careful during the install (I even have a jig that the cylinders rest against as I tap the muffler into place. I have two FG60R3's... TF GS FW190 (1/5 scale) and the TF GS Zero (1/5 scale). The most time before failure I've had is about 30 flights - all approx 7 minutes long (I only fly my 10 meneuvers -- take off, fast pass, dirty pass, military roll, loop, Immelmann, split S, figure 8, and landing (10th is flight realism). I'm currently waiting for 1 of my motors to return from HH... One day Saito will announce a fix but that's unlikely... a HH rep told me that they don't sell enough of these motors to pressure Saito. If I get lucky somebody like Moki, Kolm, or Airen will come to market with a sub-100cc radial... those companies build quality engines.
I had an FG84 for a bit and liked it as it had the RE mods... The H9 corsair did not survive due to a bad cross, air leak, and really bad judgement. Incidentally, the motors new owner ran it way too lean and it died in a bad way.
Side note: I asked a machinist in Fountain Valley what it would take to mill new cylinder heads to include beefier walls and possibly a water jacket... The idea was great until we started taking about the water cooling system locking up as I couldn't cool the coolant fast enough, vent it as necessary, the first set of cylinders would cost about $5,000 and the follow up sets would be about $600 (three cylinders), but I do have rough drawings if anyone is interested...
The first failure for that cylinder happened on the stand during break-in... 15:1 87octane and Amzoil... third or fourth 16oz tank.. it had been running for about 5 minutes at approx. 4,000RPM-full throttle (breakin needles). the second time it failed was at GunSmoke Scale Master qualifier in Mesa, AZ... Normal flight round 3 or 4 maneuvers in... 1/2 throttle, level flight, top cylinder temp approx. 185 degrees... I immediately landed and my caller had a digital infrared pyrometer (my Wulf has awesome ducting in the cowl - over the cylinders and negative-pressure vents below). I've never had this motor (either of the ones I own) at 6600RPM static... I typically have it needled at 6400RPM on a Xoar 22X10 (digital tac on the ignition box).
I've been using the Keleo exhaust for this motor after the motor is broken in... I'm always careful during the install (I even have a jig that the cylinders rest against as I tap the muffler into place. I have two FG60R3's... TF GS FW190 (1/5 scale) and the TF GS Zero (1/5 scale). The most time before failure I've had is about 30 flights - all approx 7 minutes long (I only fly my 10 meneuvers -- take off, fast pass, dirty pass, military roll, loop, Immelmann, split S, figure 8, and landing (10th is flight realism). I'm currently waiting for 1 of my motors to return from HH... One day Saito will announce a fix but that's unlikely... a HH rep told me that they don't sell enough of these motors to pressure Saito. If I get lucky somebody like Moki, Kolm, or Airen will come to market with a sub-100cc radial... those companies build quality engines.
I had an FG84 for a bit and liked it as it had the RE mods... The H9 corsair did not survive due to a bad cross, air leak, and really bad judgement. Incidentally, the motors new owner ran it way too lean and it died in a bad way.
Side note: I asked a machinist in Fountain Valley what it would take to mill new cylinder heads to include beefier walls and possibly a water jacket... The idea was great until we started taking about the water cooling system locking up as I couldn't cool the coolant fast enough, vent it as necessary, the first set of cylinders would cost about $5,000 and the follow up sets would be about $600 (three cylinders), but I do have rough drawings if anyone is interested...
After much reading of all the input, one thing hasn't been recognized. I think the cylinder walls are too thin. When the no.2 cylinder broke I test fit an old cylinder from a FG-20 and it wouldn't fit. The part of the cylinder that slides down into the block was a lot longer on the FG-20 than the FG-60 head. What happens is the counter weight hits the bottom of the cylinder. I wonder if Saito screwed up the head design. Punching it out and then shaving off a little on the bottom was just enough to weaken it to the breaking point. This could also make it more susceptible to the side forces from the exhaust ring. One thing I have noticed is, at least on my engine, the back off the cylinders were broke side to side. And the front of the cylinders remaind intact. I'm guessing that excessive heat and stress on a thin wall cylinder head is not good for longevity. So I plan on re working my baffle to wrap around the side of the heads so that air moves across the back of the cylinders. Honestly I think the heads need to be re-designed with larger fins , increased wall thickness, and beefier mounting tabs.
I believe the reason the Glow version of this engine doesn't have similar issues is that it is a cooler running engine simply because of the fuel that it runs on and it has glow ignition.
Another theory i have is that the prop hub isn't done right either. What I mean is that the magnets are not timed right. I believe no.1 is correct but no.2 is firing too early and acts like detonation and no.3 is firing late. Mix this condition with a bad plenum design that makes no.1 run lean and you end up with no.1 and 2 running the hottest and no.3 the coolest. ( I don't think the no.3 cylinder is at any risk of breaking. Lawndart, did you ever have a no.3 cylinder failure?) The magnets are timed 120* apart, but the geometry of the master rod and sister rods throws this timing set up out the window. I will try to post a video of what I mean once I get my engine back from horizon.
I'll be honest here, it was easy to be lazy and think this engine doesn't need a baffle simply because I didn't want to spend the time to do it. Mainly I didn't have a plan in mind of how to make it. So don't be like me, take the time, make an effort and baffle it. I don't see a down side to making an effective baffle.
MD
I believe the reason the Glow version of this engine doesn't have similar issues is that it is a cooler running engine simply because of the fuel that it runs on and it has glow ignition.
Another theory i have is that the prop hub isn't done right either. What I mean is that the magnets are not timed right. I believe no.1 is correct but no.2 is firing too early and acts like detonation and no.3 is firing late. Mix this condition with a bad plenum design that makes no.1 run lean and you end up with no.1 and 2 running the hottest and no.3 the coolest. ( I don't think the no.3 cylinder is at any risk of breaking. Lawndart, did you ever have a no.3 cylinder failure?) The magnets are timed 120* apart, but the geometry of the master rod and sister rods throws this timing set up out the window. I will try to post a video of what I mean once I get my engine back from horizon.
I'll be honest here, it was easy to be lazy and think this engine doesn't need a baffle simply because I didn't want to spend the time to do it. Mainly I didn't have a plan in mind of how to make it. So don't be like me, take the time, make an effort and baffle it. I don't see a down side to making an effective baffle.
MD
01-03-2017, 08:08 AM
#1178
My Feedback: (2)
Thinking about Heat being the issue there would be other tale tell signs in addition to the cylinder breaking. That much heat should leave evidence around the bearings, wear points and cylinder walls.
I haven't seen any pictures posted that demonstrate that kind of heat.
My guess is the castings are flawed. A situation that's not easy to see right off.
I don't expect Saito to ever acknowledge a problem. That's not the Japanese way..
I haven't seen any pictures posted that demonstrate that kind of heat.
My guess is the castings are flawed. A situation that's not easy to see right off.
I don't expect Saito to ever acknowledge a problem. That's not the Japanese way..
01-05-2017, 02:41 AM
#1179
My Feedback: (4)
Join Date: Apr 2003
Location: Richmond,
VA
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I would like some advice/opinions, I going to install a temp probe on my 60r so I can check the temps via telemetry. would like to know which cylinder should I install it on. I'm thinking #1 cyl. since it might run the leanest.
T
T
01-05-2017, 10:19 AM
#1182
Saito used to make a 5 cylinder 60cc glow engine: http://www.horizonhobby.com/product/...:-y-saie325r5d
Not sure if it's still available or not.
I think you could convert the FG-60 to use glow fuel.
Not sure if it's still available or not.
I think you could convert the FG-60 to use glow fuel.
01-09-2017, 02:06 PM
#1187
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After much reading of all the input, one thing hasn't been recognized. I think the cylinder walls are too thin. When the no.2 cylinder broke I test fit an old cylinder from a FG-20 and it wouldn't fit. The part of the cylinder that slides down into the block was a lot longer on the FG-20 than the FG-60 head. What happens is the counter weight hits the bottom of the cylinder. I wonder if Saito screwed up the head design. Punching it out and then shaving off a little on the bottom was just enough to weaken it to the breaking point. This could also make it more susceptible to the side forces from the exhaust ring. One thing I have noticed is, at least on my engine, the back off the cylinders were broke side to side. And the front of the cylinders remaind intact. I'm guessing that excessive heat and stress on a thin wall cylinder head is not good for longevity. So I plan on re working my baffle to wrap around the side of the heads so that air moves across the back of the cylinders. Honestly I think the heads need to be re-designed with larger fins , increased wall thickness, and beefier mounting tabs.
I believe the reason the Glow version of this engine doesn't have similar issues is that it is a cooler running engine simply because of the fuel that it runs on and it has glow ignition.
Another theory i have is that the prop hub isn't done right either. What I mean is that the magnets are not timed right. I believe no.1 is correct but no.2 is firing too early and acts like detonation and no.3 is firing late. Mix this condition with a bad plenum design that makes no.1 run lean and you end up with no.1 and 2 running the hottest and no.3 the coolest. ( I don't think the no.3 cylinder is at any risk of breaking. Lawndart, did you ever have a no.3 cylinder failure?) The magnets are timed 120* apart, but the geometry of the master rod and sister rods throws this timing set up out the window. I will try to post a video of what I mean once I get my engine back from horizon.
I'll be honest here, it was easy to be lazy and think this engine doesn't need a baffle simply because I didn't want to spend the time to do it. Mainly I didn't have a plan in mind of how to make it. So don't be like me, take the time, make an effort and baffle it. I don't see a down side to making an effective baffle.
MD
I believe the reason the Glow version of this engine doesn't have similar issues is that it is a cooler running engine simply because of the fuel that it runs on and it has glow ignition.
Another theory i have is that the prop hub isn't done right either. What I mean is that the magnets are not timed right. I believe no.1 is correct but no.2 is firing too early and acts like detonation and no.3 is firing late. Mix this condition with a bad plenum design that makes no.1 run lean and you end up with no.1 and 2 running the hottest and no.3 the coolest. ( I don't think the no.3 cylinder is at any risk of breaking. Lawndart, did you ever have a no.3 cylinder failure?) The magnets are timed 120* apart, but the geometry of the master rod and sister rods throws this timing set up out the window. I will try to post a video of what I mean once I get my engine back from horizon.
I'll be honest here, it was easy to be lazy and think this engine doesn't need a baffle simply because I didn't want to spend the time to do it. Mainly I didn't have a plan in mind of how to make it. So don't be like me, take the time, make an effort and baffle it. I don't see a down side to making an effective baffle.
MD
sorry for the bad English .... it is from google translator
I am in Italy
01-10-2017, 03:32 AM
#1189
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for a gas engine will not be very high, but on a cylinder designed to glow necessary to lower the temperature, decreasing the compression ratio, it should decrease the temperatures.
my idea do not know if right .... everything to prove
01-10-2017, 03:34 AM
#1190
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01-12-2017, 10:54 AM
#1194
Shouldn't we measure exhaust temp? Just bought an Eagle Tree logger and temp sensors. I plan to somehow mount the sensors in the exhaust stream.
01-12-2017, 12:12 PM
#1195
EGT temps are in the 800-1100F range normally. Eagle Tree sensors only measure up to about 420F.
01-12-2017, 12:30 PM
#1196
Yes indeed i also believe that 12:1 is too high.... If you want to put more gaskets try to make from metal and don't put paper, they will make your engine case flex, and that will bring more problems.
That's why i use only very good quality high octane gasoline..... to avoid knocking and i made my exhaust ring with big tube diameter to let the engine run without overstressed from back pressure. Knocking and back pressure are two major things that make engine overheat.....
That's why i use only very good quality high octane gasoline..... to avoid knocking and i made my exhaust ring with big tube diameter to let the engine run without overstressed from back pressure. Knocking and back pressure are two major things that make engine overheat.....
01-12-2017, 06:38 PM
#1197
There isn't any benefit to measuring exhaust gas temperature on this engine. EGT is used to monitor the mixture setting in full size engines...for a small engine like this you set the mixture by rpm. The reason to measure CHT instead of EGT is that CHT tells you when the engine is overheating and about to self destruct. EGT won't do that.
EGT temps are in the 800-1100F range normally. Eagle Tree sensors only measure up to about 420F.
EGT temps are in the 800-1100F range normally. Eagle Tree sensors only measure up to about 420F.
01-13-2017, 03:27 AM
#1198
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Yes indeed i also believe that 12:1 is too high.... If you want to put more gaskets try to make from metal and don't put paper, they will make your engine case flex, and that will bring more problems.
That's why i use only very good quality high octane gasoline..... to avoid knocking and i made my exhaust ring with big tube diameter to let the engine run without overstressed from back pressure. Knocking and back pressure are two major things that make engine overheat.....
That's why i use only very good quality high octane gasoline..... to avoid knocking and i made my exhaust ring with big tube diameter to let the engine run without overstressed from back pressure. Knocking and back pressure are two major things that make engine overheat.....
2) build drag propeller exact timing, I have professional CNC machines for mold construction, no problem