Saito's New Engine: FG-90R3
03-02-2021, 05:58 PM
#476
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Having run two tanks (~64 oz) of fuel through the engine, would anyone recommend going to a 20:1 mix yet? I have cleaned the plugs and want to run the engine once more before shipping it back to Horizon and am wondering if going to the standard 20:1 mix would be appropriate. If the rich mix is contributing to plug fouling, then so too is the 15:1 mix. Then again, I don't see anyone else with these issues. For what it is worth, I am using Klotz Synthetic Techniplate as my oil with 89 Octane (Ethanol Free).
07-05-2021, 12:34 PM
#477
First run today at the mountain (keeps the neighbours happy). Was able to hand start it (!).
Went through 1.5lt of 1:15 fuel. RPM was kept below 4k. Music (ring muffler) by Meier.
Instrumentation worked flawlessly and allowed me to control the heat balance/cycle of all cylinders by setting the Low needle leaner (but still rich) than the High and then making throttle adjustments*.
https://www.youtube.com/watch?v=SV9GzB-GATs
*There is a some theory behind this, but the logic loop goes like:
A. Rich carb settings = floods cold inlet chamber = "top" cylinder is usually leaner. In this video, Cylinder #1 is lower than #2 and #3 due to the stand inclination, so ehxibits the lower temps (basically, cold). Go to B.
B. One/two cylinder(s) firing = high gas pressure = increases burnt gasses blow-by = extinguishes opposite (2nd/3rd) rich cylinder (due to reverse blow-by, as piston rings are not yet seated). Go to C.
C. Reduce throttle a little = lower rpm = less frequent blow-by of firing cylinder = higher chance for opposite cylinder(s) to relight (Low needle is leaner than High). Wait until D.
D. Cold cylinder(s) relight = allow reaching of operating temp. Go to E.
E. Increase throttle a little to increase all firing temps (more frequent explosions) = high gas pressures = increases burnt gasses blow-by = extinguishes opposite cylinders or the temp of the firing cylinder(s) climb above 165C. Go to C.
Due to the volume of the inlet chamber and the hysterisis of the temp recordings, this feedback cycle takes more than 2-3 mins.
During that time, one can see the cylinders dropping and popping back up at random.
Break in is complete when:
(i) Between 1/3 and 2/3rds throttle no cylinder drops (i.e. B does not happen = all piston rings are seated properly, no reverse blow by).
(ii) Cylinder temps are within 5C of each other and less than 165C max (following the leaner carb setting possible to achieve this result).
Went through 1.5lt of 1:15 fuel. RPM was kept below 4k. Music (ring muffler) by Meier.
Instrumentation worked flawlessly and allowed me to control the heat balance/cycle of all cylinders by setting the Low needle leaner (but still rich) than the High and then making throttle adjustments*.
https://www.youtube.com/watch?v=SV9GzB-GATs
*There is a some theory behind this, but the logic loop goes like:
A. Rich carb settings = floods cold inlet chamber = "top" cylinder is usually leaner. In this video, Cylinder #1 is lower than #2 and #3 due to the stand inclination, so ehxibits the lower temps (basically, cold). Go to B.
B. One/two cylinder(s) firing = high gas pressure = increases burnt gasses blow-by = extinguishes opposite (2nd/3rd) rich cylinder (due to reverse blow-by, as piston rings are not yet seated). Go to C.
C. Reduce throttle a little = lower rpm = less frequent blow-by of firing cylinder = higher chance for opposite cylinder(s) to relight (Low needle is leaner than High). Wait until D.
D. Cold cylinder(s) relight = allow reaching of operating temp. Go to E.
E. Increase throttle a little to increase all firing temps (more frequent explosions) = high gas pressures = increases burnt gasses blow-by = extinguishes opposite cylinders or the temp of the firing cylinder(s) climb above 165C. Go to C.
Due to the volume of the inlet chamber and the hysterisis of the temp recordings, this feedback cycle takes more than 2-3 mins.
During that time, one can see the cylinders dropping and popping back up at random.
Break in is complete when:
(i) Between 1/3 and 2/3rds throttle no cylinder drops (i.e. B does not happen = all piston rings are seated properly, no reverse blow by).
(ii) Cylinder temps are within 5C of each other and less than 165C max (following the leaner carb setting possible to achieve this result).
Mate I'd be very interested in learning more about the instrumentation you are using. Assume the larger box is recording temps? The other one?
thanks in advance
cheers
P
07-06-2021, 06:19 PM
#478
Gents,
realize this is now an old thread and most will have moved on to the next shiny thing but have a few questions if I may.
I have only just purchased one of these FG-90R3 and rather apprehensive give the hit and miss experiences to date with it.
Engine is due to arrive this Friday. Yes I have read the plethora of comments regarding the break in procedure, cylinder temps, fuel ratio, types of oils etc, etc.
Is it correct that Saito made modifications to the intake design with the later FG90?
Re-reading the specs it says "updated intake design" I wonder? Updated since the first release of these engines??
Appears there are modifications available to address both in the intake fuel distribution issue & timing issue, both Ray English (RE) and Morris Mini Motors. (MMM).
I have been in touch with MMM and he did advise to get both modifications.
Is the intake modification necessary on the newer FG90?
It would be good to know if there is indeed a difference between an early FG90 & later version with the intake and with the timing.
I have read timing was 45 instead of 30 degrees BTDC.
Lastly I am looking at exhaust collector rings, understand that Keleo do one and so does MMM. Ignoring prices are there any advantages to either?
The MMM would appear to have a larger exit area and potentially a throater note.
thanks
cheers
P
realize this is now an old thread and most will have moved on to the next shiny thing but have a few questions if I may.
I have only just purchased one of these FG-90R3 and rather apprehensive give the hit and miss experiences to date with it.
Engine is due to arrive this Friday. Yes I have read the plethora of comments regarding the break in procedure, cylinder temps, fuel ratio, types of oils etc, etc.
Is it correct that Saito made modifications to the intake design with the later FG90?
Re-reading the specs it says "updated intake design" I wonder? Updated since the first release of these engines??
Appears there are modifications available to address both in the intake fuel distribution issue & timing issue, both Ray English (RE) and Morris Mini Motors. (MMM).
I have been in touch with MMM and he did advise to get both modifications.
Is the intake modification necessary on the newer FG90?
It would be good to know if there is indeed a difference between an early FG90 & later version with the intake and with the timing.
I have read timing was 45 instead of 30 degrees BTDC.
Lastly I am looking at exhaust collector rings, understand that Keleo do one and so does MMM. Ignoring prices are there any advantages to either?
The MMM would appear to have a larger exit area and potentially a throater note.
thanks
cheers
P
07-06-2021, 06:21 PM
#479
Having run two tanks (~64 oz) of fuel through the engine, would anyone recommend going to a 20:1 mix yet? I have cleaned the plugs and want to run the engine once more before shipping it back to Horizon and am wondering if going to the standard 20:1 mix would be appropriate. If the rich mix is contributing to plug fouling, then so too is the 15:1 mix. Then again, I don't see anyone else with these issues. For what it is worth, I am using Klotz Synthetic Techniplate as my oil with 89 Octane (Ethanol Free).
did anybody get back to you and have you resolved your issue? I'm not an expert by any means but the general consensus is that the fuel / oil ratio should be kept at no less than 15:1.
Remember the oil does two things, it lubricates and it removes excess heat.
07-07-2021, 06:59 AM
#480
An earlier post suggested temps should be less than 165c (329f) and cylinders within 5c (41f) of each other. This can be a bit misleading. This engine should be no where near 165c or 329f...even during break-in. I prefer high temps around 250f at full throttle. As you come off throttle while flying, temps should slowly reduce from their highs. Also, I would like to see engine temps within 15f+- of each other on the ground.
Hope this helps,
jim
07-07-2021, 02:37 PM
#481
I'm talking about the FG90 only. From what I have read and I could have it wrong thee were issues with the early release of the FG90 and it has been updated. I could be wrong as it was what I read on another post so don't quote me.
The advice I got from Morris of MMM is that the 90 does need both the back plate and timing mods done. Considering the already significant invest I have in this engine I will get the parts and do it, only money right.
I'm aware of the break in and temps, my radio does not have telemetry but I am getting the Cockpit V2 system which will give me telemetry on each cylinder, RPM, speed, height and Rx batt voltages.
Wonder if I can program it with a "*****in betty" voice, "pullup, pullup, low terrain"
cheers
P
The advice I got from Morris of MMM is that the 90 does need both the back plate and timing mods done. Considering the already significant invest I have in this engine I will get the parts and do it, only money right.
I'm aware of the break in and temps, my radio does not have telemetry but I am getting the Cockpit V2 system which will give me telemetry on each cylinder, RPM, speed, height and Rx batt voltages.
Wonder if I can program it with a "*****in betty" voice, "pullup, pullup, low terrain"
cheers
P
07-07-2021, 04:50 PM
#482
I'm talking about the FG90 only. From what I have read and I could have it wrong thee were issues with the early release of the FG90 and it has been updated. I could be wrong as it was what I read on another post so don't quote me.
The advice I got from Morris of MMM is that the 90 does need both the back plate and timing mods done. Considering the already significant invest I have in this engine I will get the parts and do it, only money right.
I'm aware of the break in and temps, my radio does not have telemetry but I am getting the Cockpit V2 system which will give me telemetry on each cylinder, RPM, speed, height and Rx batt voltages.
Wonder if I can program it with a "*****in betty" voice, "pullup, pullup, low terrain"
cheers
P
The advice I got from Morris of MMM is that the 90 does need both the back plate and timing mods done. Considering the already significant invest I have in this engine I will get the parts and do it, only money right.
I'm aware of the break in and temps, my radio does not have telemetry but I am getting the Cockpit V2 system which will give me telemetry on each cylinder, RPM, speed, height and Rx batt voltages.
Wonder if I can program it with a "*****in betty" voice, "pullup, pullup, low terrain"
cheers
P
If you have the time, money, skills, and a hub puller, then give it a go. Just saying, the engine will run fine with or without them. I've seen the FG 90 both ways.
07-11-2021, 06:02 AM
#483
It is very important to use contact thermometers instead of the IR junk (measurements are relative with IR, not absolute like contact). I have since replaced it with my trusty Jeti telemetry.
The other box is just an RCExl RPM readout feeding off the ignition output.
Head temps and RPM is all you need..
BR,
Hector.
07-11-2021, 06:22 PM
#485
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I have a stock FG-90 and a FG-60 with keleo rings, I’ve built up a huge amount of hours on them now without issue.
I can assure you the FG-90 is absolutely faultless, however baffling is an absolute must. More so on the FG-90 than the FG-60, if you baffle these motors they will last forever.
I completed the run in via, 1ltr on the bench and than 2 litres of the rich mix in the air (avoiding full throttle for long periods of time). Then I went straight to the default mix and optimum RPM, I fly my 90 hard i monitor temps with Jeti RPM and Temp sensors however the baffling keeps the motors at a constant safe temp.
I can assure you the FG-90 is absolutely faultless, however baffling is an absolute must. More so on the FG-90 than the FG-60, if you baffle these motors they will last forever.
I completed the run in via, 1ltr on the bench and than 2 litres of the rich mix in the air (avoiding full throttle for long periods of time). Then I went straight to the default mix and optimum RPM, I fly my 90 hard i monitor temps with Jeti RPM and Temp sensors however the baffling keeps the motors at a constant safe temp.
Gents,
realize this is now an old thread and most will have moved on to the next shiny thing but have a few questions if I may.
I have only just purchased one of these FG-90R3 and rather apprehensive give the hit and miss experiences to date with it.
Engine is due to arrive this Friday. Yes I have read the plethora of comments regarding the break in procedure, cylinder temps, fuel ratio, types of oils etc, etc.
Is it correct that Saito made modifications to the intake design with the later FG90?
Re-reading the specs it says "updated intake design" I wonder? Updated since the first release of these engines??
Appears there are modifications available to address both in the intake fuel distribution issue & timing issue, both Ray English (RE) and Morris Mini Motors. (MMM).
I have been in touch with MMM and he did advise to get both modifications.
Is the intake modification necessary on the newer FG90?
It would be good to know if there is indeed a difference between an early FG90 & later version with the intake and with the timing.
I have read timing was 45 instead of 30 degrees BTDC.
Lastly I am looking at exhaust collector rings, understand that Keleo do one and so does MMM. Ignoring prices are there any advantages to either?
The MMM would appear to have a larger exit area and potentially a throater note.
thanks
cheers
P
realize this is now an old thread and most will have moved on to the next shiny thing but have a few questions if I may.
I have only just purchased one of these FG-90R3 and rather apprehensive give the hit and miss experiences to date with it.
Engine is due to arrive this Friday. Yes I have read the plethora of comments regarding the break in procedure, cylinder temps, fuel ratio, types of oils etc, etc.
Is it correct that Saito made modifications to the intake design with the later FG90?
Re-reading the specs it says "updated intake design" I wonder? Updated since the first release of these engines??
Appears there are modifications available to address both in the intake fuel distribution issue & timing issue, both Ray English (RE) and Morris Mini Motors. (MMM).
I have been in touch with MMM and he did advise to get both modifications.
Is the intake modification necessary on the newer FG90?
It would be good to know if there is indeed a difference between an early FG90 & later version with the intake and with the timing.
I have read timing was 45 instead of 30 degrees BTDC.
Lastly I am looking at exhaust collector rings, understand that Keleo do one and so does MMM. Ignoring prices are there any advantages to either?
The MMM would appear to have a larger exit area and potentially a throater note.
thanks
cheers
P
Last edited by su27flanker; 07-11-2021 at 10:16 PM.
07-11-2021, 10:05 PM
#486
I've obtained the baffle .DXF files for the baffles to suit the TopRC FW-190 and a friend will cut it on his laser cutter. Agree about the baffles.
I've invested in the MMM rear induction plate and their timing ring as well as the exhaust collector ring.
I've invested in the MMM rear induction plate and their timing ring as well as the exhaust collector ring.
07-12-2021, 11:47 AM
#487
100% on the baffling. And another 2 points from my experience. Make sure the fuselage interior is well ventilated; both the -90 and -60 carb trumpets protrude behind the firewall and feed off the air plenum of the fuselage interior. The speed variance of the plane can create varying pressure differences inside the fuselage. Furthermore, higher "ambient" temperatures can bleed in from the hot cowl compartment, also affecting the breathing of the engine. Both of those may start spoiling the tune of the engine halfway through the flight, resulting in gradual power loss and "laboring" operation. A small inlet on one side and some venting holes in the back neutralise both dynamic effects. Just my 0.02.
08-05-2021, 02:17 PM
#489
Join Date: Apr 2007
Location: Clarksville, TN HI
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Looking for some assistance... I've got a FG90R3 in a EF Yak 54 with a CH Ignition prop hub and a Keleo exhaust running 20:1 Klotz. This engine ran well in a Corsair before this aircraft if not a little hot, 250-265F full out a couple times. The issue I'm having with his bird is that I'm trying to tune the motor with a new prop, Bolly 24x12 and it runs pretty well for the first cold run. I'm getting 6200rpm on the ground. After shutting down to refuel, it just doesn't want to restart. If I can get it running, the motor will idle fine but I cannot advance the throttle more than 1/4-3/8 before it starts to run really rough and I'll have to return to idle before it dies. The plugs are new, tappets were adjusted at that time. The engine is fully baffled in the cowl. Turns are 5 main needle and 3-3.5 slow needle. Any ideas?
08-05-2021, 02:27 PM
#490
Sounds like it is getting very hot and you are getting vapor lock.
Is it baffled? I'd also suggest that is too much prop for the engine and you are overloading it.
Advice I got for mine from the guru Ray English was to use a 20x12. That is in a 3 blade prop.
2 blade possibly 22x12.
Consider going to 15:1 klotz as the additional oil will aid with cooling.
Is it baffled? I'd also suggest that is too much prop for the engine and you are overloading it.
Advice I got for mine from the guru Ray English was to use a 20x12. That is in a 3 blade prop.
2 blade possibly 22x12.
Consider going to 15:1 klotz as the additional oil will aid with cooling.
08-05-2021, 10:34 PM
#491
Hello Jesse,
Yes it seems running too hot, 24x12 is the right propeller for the R90, 22x12 is for the FG84.
20:1 is not enough use 15:1 and try to baffle it.
Also try to stay around 5900/ 6000 RPM max on ground, it will take close to 7000RPM in dive.
Fly safe,
Alain
Yes it seems running too hot, 24x12 is the right propeller for the R90, 22x12 is for the FG84.
20:1 is not enough use 15:1 and try to baffle it.
Also try to stay around 5900/ 6000 RPM max on ground, it will take close to 7000RPM in dive.
Fly safe,
Alain
Last edited by raptormasque; 08-05-2021 at 10:37 PM.
08-06-2021, 02:48 AM
#492
Hello Jesse,
Yes it seems running too hot, 24x12 is the right propeller for the R90, 22x12 is for the FG84.
20:1 is not enough use 15:1 and try to baffle it.
Also try to stay around 5900/ 6000 RPM max on ground, it will take close to 7000RPM in dive.
Fly safe,
Alain
Yes it seems running too hot, 24x12 is the right propeller for the R90, 22x12 is for the FG84.
20:1 is not enough use 15:1 and try to baffle it.
Also try to stay around 5900/ 6000 RPM max on ground, it will take close to 7000RPM in dive.
Fly safe,
Alain
08-06-2021, 03:32 AM
#494
I can see the needs for the modifications to the 84 , but they're not necessary on the 90 . Saito incorporated the majority of the Ray English mods in the 90 at the factory . The 84 has been run successfully without the mods but it runs much better with the updated intake plenum for better fuel/air distribution . The key to a long life of both the 84 and 90 is to run 15:1 mix and keep the static rpms at or below 6000 rpm and unloaded rpms below 7200 rpm. Baffling is a must for proper cooling in a cowled engine to keep the cylinder temps below 250f max temp
08-06-2021, 05:37 AM
#496
SJN , I'm sure yours does run great . Many of the 84's are out there running great with no mods made to them. Don't overload them , don't overheat them and don't over rev them and they will be fine . The biggest issue I have seen with the 84 and why I say the plenum mod makes them run better is tuning . If you're good at tuning you can tune around most of the 84's running issues. Most are are not patient enough or adept enough at the Saito FG's particular tuning needs , and the Ray English plenum makes that seemingly difficult tuning much easier . But of course there are always exceptions to the rule , there will always be engines that grenade themselves purely because they can , any engine can at any time . And yes , High quality oil does improve the life of the engine by better lube to crucial areas ( crank pin especially) , and better heat dissipation.
08-08-2021, 04:28 PM
#497
I'm installing a 90FG on the Black Horse Gilmore Red Lion. I have the Keleo ring. In order to fit over the motor box, I need to use the longer stand-off's. The problem is getting the longer bolts into the hole. The fins between the cylinders are over the bolt hole. Is there some trick to getting the longer bolts to fit?
08-08-2021, 04:47 PM
#498
I used 10-32 studs into the firewall on my Zero and Corsair . Install the studs , get the length you need , remove ,cut off the extra then permanently Install them . Use lock nuts at the engine
08-09-2021, 01:41 AM
#500
So what did you do on the inside of the firewall? Still use a blind nut? Using your suggestion, I'm thinking just use a 10-32 bolt with the head inside the firewall, maybe a washer between the head and the firewall, run it through the firewall, then through the standoffs, then through the hole in the engine, then the lock nut. Tighten with a ball driver. Is that the idea?