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Saito's New Engine: FG-90R3

Old 02-05-2022, 01:44 PM
  #601  
Jesse Open
 
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Originally Posted by BarracudaHockey
Yep, have you been to the grocery store lately or the gas station? Everything is going up
I see some grocery stores are going to use remote control pricing signs, similar to a small version those used in gas stations.
Some prices are going up three times a day.
Seems inflation is becoming a lot like pre-war Germany. History repeats.
Old 02-07-2022, 06:41 PM
  #602  
Edgar Perez
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Anyone know what is the minimum temperatures when a cylinder is running?
Doing my break-in and always getting a cylinder with much cooler than the other two. I rotate the engine, so it not always the same one (not even always the bottom one)

My measured temperature before starting was 82 degrees Fahrenheit. Temperature varied widely when running very rich from 160 degrees to 230 degrees Fahrenheit. However sometimes one cylinder will be say 120 degrees. Thinking it was still running but wondering if it was just the heat transfer from the other cylinders..

Thanks
Old 03-06-2022, 03:04 PM
  #603  
Jaketab
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Getting ready to install the FG90 on a TRC Zero. Question for those who have the Keleo exhaust ring.
What are you using to seal the threads?
Thinking Teflon tape will be OK or is something like Ultra Copper or Ultra Black a better choice???

Thanks - J Tab
Old 03-09-2022, 06:54 PM
  #604  
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Teflon tape is better than the silicone stuff.
I have been using anaerobic teflon paste called SWAK, which can be hard to find and and the miserly type groan over the price

Better yet, Loctite makes a similar anaerobic teflon paste that is easier to find and comes in smaller, cheaper tubes. I much prefer either over the best of teflon tapes.


Prevents loosening, lubricates and protects threads.

Last edited by Jesse Open; 03-09-2022 at 07:07 PM.
Old 03-12-2022, 11:16 AM
  #605  
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what do you guys use for a plug wrench i cant get any sockets or other wrenches to work....help with a link or picture of something i can buy that will fit. it seems its 14mm
Old 03-12-2022, 12:02 PM
  #606  
CK1
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The CM-6 plug is 14mm or 9/16" sae . I use the sparkplug tool that came with the engine .
Old 06-14-2022, 07:13 AM
  #607  
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Iím starting to fly my Boeing F4B with a Saito FG-90 radial. I wanted to fly yesterday but I could only get 4700 rpm with a 24x12 prop. Iím going to check valve lash first. Any other reason for this?
I've also noticed that the ignition is using about 900 mAh per flight from a dedicated ignition battery. Seems like a lot. I didnít even fly yesterday and I put 2000 mAh in the pack when charging this morning. Luckily, my ignition battery is a 6800 mAh LiThium Ion. Anyone else seeing this?
Old 06-14-2022, 07:35 AM
  #608  
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I'm flying 7 minutes and using maybe 350mah total (including the HV flight servos and a tech aero IBEC powering the ignition) on my H9 Corsair.
Old 06-14-2022, 03:22 PM
  #609  
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I've got one on the front of a Gilmore Red Lion. Uses about 300-400 mah per flight. I'm always amazed at how little fuel it burns in an 8 minute flight!
Old 06-14-2022, 11:46 PM
  #610  
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Originally Posted by RCdude13
Iím starting to fly my Boeing F4B with a Saito FG-90 radial. I wanted to fly yesterday but I could only get 4700 rpm with a 24x12 prop. Iím going to check valve lash first. Any other reason for this?
I've also noticed that the ignition is using about 900 mAh per flight from a dedicated ignition battery. Seems like a lot. I didnít even fly yesterday and I put 2000 mAh in the pack when charging this morning. Luckily, my ignition battery is a 6800 mAh LiThium Ion. Anyone else seeing this?
Check the spark plugs and set the gap as per the manual. Next I would lean it out on the the needle to see if its too rich
Old 07-09-2022, 08:40 AM
  #611  
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Just to report what a difference a change in props makes on my 33# TRC Zero. I was using the Biela Corsair style 23 x 10 x 3. Performance was not so good, and the temps climbed above 250F when going to full throttle. Switched to a Xoar 24 x 12 x 2. Temps stay under 235F and the performance difference is remarkable. One other prop I would like to try is a Biela 22 x 12 x 3, but I don't believe any scale 3 blade is going to outperform a 2 blade prop.

Regards - J Tab
Old 07-09-2022, 12:08 PM
  #612  
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Xoar 23x10x3 WW II prop performs pretty nicely on my H9 Corsair
Old 08-21-2022, 09:48 AM
  #613  
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The Saito FG90R3 ignition appears to have going kaput suddenly. After several hours of excellent fly time, the ignition appears to have gone bad.
Warming up for a flight and the engine quit for no explanation. Voltage good and nothing else on engine out of ordinary.
Questions: Anyone else experience a bad ignition module? Is there any test for the ignition I can perform before contacting Horizon?

Hoping that Horizon will except only the return of the module for warranty without sending in the 6-month-old engine.

Thanks - J Tab

BTW - the FG90R3 is the easiest starting and best running engine in my fleet. No complaints up to now.

Old 08-21-2022, 12:50 PM
  #614  
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Jaketab, at first I thought it was the ignition too but I was getting spark at the plugs. I found that mine was not drawing fuel so the carburetor just gave up pumping fuel. I replaced the carburetor and that solved the problem. The FG 90 is back to running like a well oiled Swiss watch.
Old 08-21-2022, 12:56 PM
  #615  
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First check whether the Hall element is not the issue. Extremely rare but known to happen, or possibly a wire breakage.
Old 08-21-2022, 02:57 PM
  #616  
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Originally Posted by 1967brutus
First check whether the Hall element is not the issue. Extremely rare but known to happen, or possibly a wire breakage.
It could be the hall sensor, but it looks good by visual exam. The carb is pumping and working fine. Very wet.
I removed the plugs from cylinders and inserted the plugs back into the caps. Ignition module connected directly to charged 7.4 v Li Ion. Rotation of prop reveals no spark being sent to or produced by the spark plugs.
Old 08-21-2022, 03:47 PM
  #617  
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Perhaps the passing distance between sensor and magnet has changed? Are the magnets still "magnetic"? If you have had a hot run, and the shaft got over 170F, there is a possibility the magnetism is gone.,
Old 08-30-2022, 12:53 PM
  #618  
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Installed the new warranty replacement ignition today. That confirmed 100% that the ignition was the problem.
The original ignition decided to quit without advance warning symptoms. Back to flying now.
Old 03-08-2023, 04:28 PM
  #619  
RichardGee
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Has anyone measured FG-90 fuel consumption at full throttle?
I would be very interested in your findings. I am assuming close to 2 ounces a minute, but ??

Also, it seems the valve adjustment "feeler gauge" provided with the engine is only used to confirm there is SLIGHTLY LESS gap between rocker foot and valve stem than the thickness of the gauge.
The illustration in the manual seems to suggest the adjustment gap should be very close to zero (cold).
Does this seem correct?

Last edited by RichardGee; 03-09-2023 at 06:31 AM.
Old 03-08-2023, 05:07 PM
  #620  
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I have one in a TRC Zero. Don't fly full throttle, but I can tell you the engine is very fuel efficient.
My tank is a 500 ml Fiji water bottle. I can fly for 12-15 minutes with about 1/3 reserve.
At full throttle I would go with at least 24 oz. for a 10-minute flight.

I gap at .0025" to .003". Yes - gap very close to zero. Just to barely see daylight in the gap.
After a good run-in, the valve gap adjustments seem to hold very well with minimum adjustments.
The FG90 is the easiest starting engine I have owned.
I wish my 2 Moki radials would start that easy.

Regards - J Tab

Last edited by Jaketab; 03-08-2023 at 05:09 PM.
Old 03-08-2023, 05:41 PM
  #621  
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Originally Posted by Jaketab
I have one in a TRC Zero. Don't fly full throttle, but I can tell you the engine is very fuel efficient.
My tank is a 500 ml Fiji water bottle. I can fly for 12-15 minutes with about 1/3 reserve.
At full throttle I would go with at least 24 oz. for a 10-minute flight.

I gap at .0025" to .003". Yes - gap very close to zero. Just to barely see daylight in the gap.
After a good run-in, the valve gap adjustments seem to hold very well with minimum adjustments.
The FG90 is the easiest starting engine I have owned.
I wish my 2 Moki radials would start that easy.

Regards - J Tab
THANKS for that.
I am trying to determine just how much 'cushion' I have on flight time... and like you, I would not be flying the entire time at full throttle.
Based on your flying style, your FG-90 is consuming, at most, 1.2 oz /. minute avg.
IF I have 20 ounces of available fuel, and fly my warbird in the same manner, that puts me on empty after just over 16.5 minutes.
I RARELY fly any aircraft more than 10 minutes, so I would think 20 ounces would be plenty of fuel, even if I were doing lots of full throttle maneuvers

I just checked all my valve adjustments, but used the supplied gauge as THE required gap, so no doubt all of them are TOO LARGE/loose. I will go back around and re-check.

FYI - I broke in my FG-90 exactly as described by Saito and am running it on Amsoil Dominator @ 20:1.
I just recently replaced the stock prop/TIMING hub with the CH... as per the others who have struggled with this, I TOO tried to use a cheap two jaw puller and only managed to GOUGE the CRAP out of my stock hub!
After acquiring a better 3-jaw puller, I was successful. I did NOT apply heat and it did seem like the amount of pressure required to pull the hub was EXCESSIVE, but it finally popped off and the CH installed with no issues.

The CH hub did not make a HUGE difference, but I can definitely see the engine has a smoother idle and transition. I lost about 200 rpm at full throttle, but this is to be expected since the timing advance is less with the CH... I now see about a 20 degree difference in temperature between the cylinders and at full throttle none are exceeding 200 degrees.

My FG-90 runs SO SWEET, it should be ILLEGAL It will idle down to under 1000 rpm for prolonged periods and recover INSTANTLY to full throttle.
I am spinning a Biela 22x12 Corsair style 3-blade prop and top rpm on the bench is just over 6100.

I have a custom-made KELEO exhaust ring with two stacks and to be perfectly honest, the IDLE sounded better with the stock timing hub since the overly advance timing made the idle incredibly "lopey"
However, I will settle for smooth and cool over lopey...

My ONLY complaint about this engine is the amount of BLACK GOO it vomits forth from the exhaust! I have a Saito FG-14C and it too spews out TONS of black GOO!!
IS IT the AMSOIL DOMINATOR I AM USING??

I got out of glow to eliminate the mess, but these gassers that require minimum 5% oil are nearly as messy!

I have owned and flown two Mokis: 250 and 180. BOTH started EASILY as long as I did NOT use an auxiliary fuel pump!
The pump FLOODED the engines.
Eliminating the pump made them start, by hand, just like any other good gas engine, and I never had any fuel starvation problems using the stock air pump as long as the feed line was kept clean.
Old 03-09-2023, 01:48 AM
  #622  
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Originally Posted by RichardGee
My ONLY complaint about this engine is the amount of BLACK GOO it vomits forth from the exhaust! I have a Saito FG-14C and it too spews out TONS of black GOO!!
IS IT the AMSOIL DOMINATOR I AM USING??
The black goo is not caused by your oil, but by the fact that a carburettor never produces a "perfect mixture", and that effect is amplified by unequal fuel distribution over the cylinders.
ANY decent 2-stroke oil will leave the exhaust in at worst a slightly darkened condition if the mixture is 100% correct, but that is near impossible to achieve using a carburettor, because the fuel does not have time to FULLY evaporate before reaching the combustion chamber. The presence of fuel in liquid state in the combustion chamber, at commencement of compression is what is causing the blackness. It is extremely hard to achieve 100% evaporation in the intake tract in these tiny engines. It is possible, but that is subject of a different section of this forum.

A bit deeper into it: an engine running lean or rich as we perceive it (judging by throttle response, peak power and sound) is mainly depending on the ratio between air and evaporated fuel, because that ratio determines the ignitability of the mixture. The part of the fuel that is still liquid when the spark comes, does not take part in that ignitability.
So let's assume, the fuel/vapour ratio is "perfect", just as a starting point. That fuel/vapour mix would on its own burn clean, smokeless and without soot formation.
But once the charge is ignited, the fuel present in liquid state, will also take part in the combustion, and immediately the burn turns rich and starts producing smoke and soot.
You won't notice this as "rich" because this part happens AFTER the combustion has started, and how you perceive the engine to run by ear (rich or lean) depends on the ignitability of the fuel/vapour part of the fresh charge.

Now this fuel that is still liquid, ALSO is still in solution with the oil in the fuel. That means that the tiny droplets are a pretty thick fuel/oil mix (maybe 1:1 or worse) and now you have tiny globules of mix, of which the fuel burns off in an increasingly oxygen-deficient environment ("producing soot") and oil which barely takes part in the combustion, BUT this oil due to its cleaning and detergent action, absorbs the soot. Result is blue smoke and black crud.

There is very little you can do about it, it is not in the specific oil you use, it also is not in the fuel/oil ratio: If you would, for example, start using 15:1 instead of 20:1, you would not see a really significant change in the gooeyness, nor the amount. A little bit, but not as much as expected. If you would use 25:1 (mind you, I am NOT advising this) you would see no significant reduction of goo. But you would most defintiely see increased wear and reduced engine life. Meaning, the gooeyness is NOT about "too much oil".

The only thing that would help, is provisions to promote fuel evaporation during transfer from carb to intake valve.
For example a very fine metal screen downstream of the carb. For experimenting and gain of understanding an interesting thing to do, but for practical use probably not very advisable, because fine-mesh screens clog over time, leading to issues that would really ruin your flying day.
Another method would be fuel injection instead of conventional carburation, but while absolutely possible (people have done it), it is not an off the shelf solution and involves a lot of tinkering.

Best is to just accept it. The black goo is nasty but still WAY easier to clean than Castor-goo.

Last edited by 1967brutus; 03-09-2023 at 02:00 AM.
Old 03-09-2023, 07:22 AM
  #623  
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That goo is very bad on my engine's catalytic converters. 
Speaking of the nasty black goo, WD-40 works for me to clean it off, then followed by your favorite detergent mix.
I don't worry so much about it on my Zero. The black residue on the front of the lower fuel tank looks cool and scale like.
I get very little exhaust residue with my Moki's or Valach running at 50/1 or 30/1.
Amsoil Dominator in all my engines.

J Tab
Old 03-09-2023, 08:43 AM
  #624  
RichardGee
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What is interesting about the Saito exhaust residue, is, it is my understanding a Walbro carburetor is NOT an ideal fuel distribution device for a radial or any multi-cylinder engine.
That said, NONE of my Walbro equipped gas four strokes spew the goo like my Saitos.
I have many flights on a RotoMotors 85 inline twin, running 30 to 40:1 Amsoil, and the engine exhaust is dark, but dry... VERY clean when compared to a Saito.
Dittos my Moki radials.
Goetz Vogelsang has said the Saito carburetor is superior to the Walbro for a radial... WHY does it not provide a mixture that burns more efficiently?
Old 03-09-2023, 08:48 AM
  #625  
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In regards to the FG-90's fuel consumption... I sent that question to Horizon's "tech support," letting them know I had purchased the engine new from Horizon (also two FG-60s - which I also asked about fuel consumption)

Their answer? "Saito does not list fuel consumption on its motor specifications."

My mental response? DUH!!!!!!!!!!!! I can read the Owners manual and product specs. WHY do you think I am asking you guys?

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