Saito's New Engine: FG-90R3
#626
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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?
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?
Walbroes are maybe pretty good at metering fuel, but not all that good at mixing the two properly, period. At least the small ones for weedwhackers and our model engines. Not talking about the Walbroes intended for jetskis, skidoos and bikes, those are quite a bit better at it, because they have features like secondary air circuits and emulsion tubes and such.
Glow carbs also suck at it, but those usually get assistance from a spinning crankshaft (2-strokes) or a hot header tube, and glow fuel is less sensitive to it anyway due to its very wide ignitability range. Gasoline is a bit more finicky in that respect.
Your big walbro equipped gasers also run an entirely different fuel/oil ratio, the amount of oil needed to create that big mess simply is not there... I might have said that 20:1 versus 15:1 does no not make a whole lot of difference, but 50:1 DOES make a difference.
2-stroke oil does not really burn off during combustion. A tiny bit does though. Now when there is 5% oil in the fuel, chances are, most of it leaves the exhaust still in liquid state. Some of it burns, most of it not
When there's only 2 or 2,5% of it, chances are most of it either burns off, or evaporates, leaving zero to none "wet" oil messing up your plane.
Last edited by 1967brutus; 03-09-2023 at 09:57 AM.
#627
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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?![Stick Out Tongue](https://www.rcuniverse.com/forum/images/smilies/tongue.gif)
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?
![Stick Out Tongue](https://www.rcuniverse.com/forum/images/smilies/tongue.gif)
Had I been in their shoes, I would have responded the same. Why take the risk of a dissatisfied customer? It consumes what it consumes, the customer will find out soon enough how much that actually is.
Now would a customer ask me is a given consumption is acceptable/correct, then I could have answered with a comment like "yes that is to be expected" or "no, probably something is wrong". But not before.
But to answer your question: Without owning one, but based on education, theoretical knowledge and experience with various different fourstrokes in different configurations, for that FG90R I would expect a WOT fuelconsumption of around 90 oz/hr, give or take 10-ish In other words, somewhere between 80 and 100 oz/hr. More with smaller/lighter props, less with larger/heavier props
Last edited by 1967brutus; 03-09-2023 at 10:11 AM.
#628
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I fill up my Hangar 9, rip around for 10 minutes which is about as much as I can stand, land and have half a tank left, If you can track down that tank size you might be in the ball park.
The problem with asking Horizon is you might get a guy that knows one thing and get a dissertation back on RC cars or whatever he's into but if you ask a Saito question he looks in the manual. Versus catching the guy that actually flys giant scale and might give you a better answer.
The problem with asking Horizon is you might get a guy that knows one thing and get a dissertation back on RC cars or whatever he's into but if you ask a Saito question he looks in the manual. Versus catching the guy that actually flys giant scale and might give you a better answer.
#631
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interesting discussion on the black goo. My Saito FG-90R3 was spewing copious amounts of black goop but after about 2 - 3 hrs of running has decreased a lot.
The worst engines I have for that is my MVVS 30 (walbro) & DLE-111 (DLE carb), both leave a thick mess after flying all over the model and it is a pain to clean off. I will try what the other chap suggest with WD-40 then some kitchen spray cleaner.
Water Displacement #40 has many good uses!! Not just for Thikol missiles!
Having said that as I have a mix of older well run in engines and new ones I tend to just have one can of fuel I use in all of them and it runs Castrol TT mineral 2 stroke oil, 91 or 95 petrol @ 32:1. Note our octane rating here is different to you guys across the ditch.
95 is hard to find here, my local BP only has 91 or 98 and you have to watch you do not get an ethanol blend with the lower octanes here.
Rough approximation I stole from Dr Google:
USA 91 MON is similar to Australian 95 RON
USA 93 MON is similar to Australian 98 RON
USA 87 MON is similar to Australian 91 RON
cheers
me
The worst engines I have for that is my MVVS 30 (walbro) & DLE-111 (DLE carb), both leave a thick mess after flying all over the model and it is a pain to clean off. I will try what the other chap suggest with WD-40 then some kitchen spray cleaner.
Water Displacement #40 has many good uses!! Not just for Thikol missiles!
Having said that as I have a mix of older well run in engines and new ones I tend to just have one can of fuel I use in all of them and it runs Castrol TT mineral 2 stroke oil, 91 or 95 petrol @ 32:1. Note our octane rating here is different to you guys across the ditch.
95 is hard to find here, my local BP only has 91 or 98 and you have to watch you do not get an ethanol blend with the lower octanes here.
Rough approximation I stole from Dr Google:
USA 91 MON is similar to Australian 95 RON
USA 93 MON is similar to Australian 98 RON
USA 87 MON is similar to Australian 91 RON
cheers
me
Last edited by planenutzz; 03-09-2023 at 02:10 PM.
#632
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Judging by the size of the plane, the engine size it was designed for and experience with other planes of similar size, I't say it came with a 1 litre-ish (32 oz-ish) tank. At least, my Seagull FW190A came with that size. If true, that indeed would suggest a fuel consumption of approx 90 oz/hr
Last edited by 1967brutus; 03-10-2023 at 04:00 AM.
#633
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Try Castrol PowerRS 2-stroke (might be called Castrol TTS in some places). Your engines will like it.
Last edited by 1967brutus; 03-09-2023 at 02:18 PM.
#634
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Look at it from their side: If Saito provides that info, for them it is safe to convey it to you. If Saito does not, it would require them to do measurements. Measurements take time and cost money, that they won't earn back by selling more engines, but which can lead to dissatisfied customers if a customers experience for whatever reason would not match their numbers. And since practical fuel consumption is depending on a LOT of variables, no way of telling if that will be the case.
Had I been in their shoes, I would have responded the same. Why take the risk of a dissatisfied customer? It consumes what it consumes, the customer will find out soon enough how much that actually is.
Now would a customer ask me is a given consumption is acceptable/correct, then I could have answered with a comment like "yes that is to be expected" or "no, probably something is wrong". But not before.
But to answer your question: Without owning one, but based on education, theoretical knowledge and experience with various different fourstrokes in different configurations, for that FG90R I would expect a WOT fuelconsumption of around 90 oz/hr, give or take 10-ish In other words, somewhere between 80 and 100 oz/hr. More with smaller/lighter props, less with larger/heavier props
Had I been in their shoes, I would have responded the same. Why take the risk of a dissatisfied customer? It consumes what it consumes, the customer will find out soon enough how much that actually is.
Now would a customer ask me is a given consumption is acceptable/correct, then I could have answered with a comment like "yes that is to be expected" or "no, probably something is wrong". But not before.
But to answer your question: Without owning one, but based on education, theoretical knowledge and experience with various different fourstrokes in different configurations, for that FG90R I would expect a WOT fuelconsumption of around 90 oz/hr, give or take 10-ish In other words, somewhere between 80 and 100 oz/hr. More with smaller/lighter props, less with larger/heavier props
Well, your calculation is about what I assumed from Jaketab's post and the 'mileage' he was getting from the tank in his Zero.
I do find 1.5 ounces a minute at WOT to probably be about right.
I am not a big fan of running radials WOT for any length of time on the test bench, which is why I didn't (or haven't) measured consumption myself.
The issue of fuel consumption is important based on a number of limiting factors with my current tank install.
#635
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My Zenoahs, DA, DLE etc are happy to run on the racing motor bike oils. Though I have a mate who is talking me into running on redline so I bought some, not tried it yet.
Will probably need to have about 4 cans with various oils and mixes!!
Run in standard engines 40:1 redline
New engines 32:1 castrol mineral TT
Saito FG90 Klotz KL200 @ 15:1, interestingly my little FG-21 is 20:1 - maybe once the 90 is full run in I can just stick to the 20:1 ??
Supertigre ST2500 converted to petrol will be klotz KL200 @ 12% or approx 8:1, remember this had been a glow engine and does not have bearing races.
#636
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Engines do that. In general the residue decreases after a few hours of runtime. Fairly common phenomenon. They also generally accept leaner mixture and make more power.
Try Castrol PowerRS 2-stroke (might be called Castrol TTS in some places). Your engines will like it.
Try Castrol PowerRS 2-stroke (might be called Castrol TTS in some places). Your engines will like it.
#637
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Saito does provide fuel consumption for some of their gas four stroke singles, just not their multi-cylinder engines. Example: The FG-40 consumes 30cc/minute @ 7500 rpm
Well, your calculation is about what I assumed from Jaketab's post and the 'mileage' he was getting from the tank in his Zero.
I do find 1.5 ounces a minute at WOT to probably be about right.
I am not a big fan of running radials WOT for any length of time on the test bench, which is why I didn't (or haven't) measured consumption myself.
The issue of fuel consumption is important based on a number of limiting factors with my current tank install.
Well, your calculation is about what I assumed from Jaketab's post and the 'mileage' he was getting from the tank in his Zero.
I do find 1.5 ounces a minute at WOT to probably be about right.
I am not a big fan of running radials WOT for any length of time on the test bench, which is why I didn't (or haven't) measured consumption myself.
The issue of fuel consumption is important based on a number of limiting factors with my current tank install.
No fan of running radials at WOT on the ground either, but if this helps:
If you can do a decent peak RPM measurement, take a good propcalculator and check what output that translates to. Use output in kW (HP x 0,735)
Your engine will by and large (generally accepted rule of thumb for a naturally aspirated gasoline engine) consume 300 grammes of fuel (not counting the oil) per kW per hour.
That converts to 14,1 oz per hp per hour.
I just checked Saito's specs on that engine and Saito claims the engine can produce 6 hp, so that would suggest it is capable of consuming about 84~85 oz of gas per hour, excluding the oil. At 20:1 that would mean we need to add some 4,25 oz to that, and then we are pretty close to the 90 oz I estimated earlier. I only have to retract the "give or take"... Consumption could be less (depending on propsize and throttle regime), but most likely not more than 90 oz per hour.
Last edited by 1967brutus; 03-10-2023 at 03:59 AM.
#638
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The warranty condition (Use Klotz or else...) is a dealbreaker of course, but if it is of any help, I know for a fact that a Saito WILL survive on TTS just as well, I have run enough of them even ones that did not leave the factory as a gasser originally to know for sure. I would, in ANY case, not use mineral oil in a Saito single cylinder FG though, on account of the unbushed conrod.
Castrol TTS (later renamed to PowerRS-2stroke) was recommended to me by my local motorcycle workshop owner, who is an avid off-roader. He sells oil and has a shelf full of different brands, all reputable. He was very specific on the TTS' ability to cope with lack of cooling due to mud-caked cooling fins and that was what I was looking for, because I convert glow engines to gasoline, and that means "limited cooling" for me is a given. I need an oil that can handle that. The Castrol proved to do as advertised, I have seen a few engines survive several minutes close to 200 deg CHT (Celsius, not Fahrenheit) without damage.
But it also helps that I can get it for less than €7/litre including free delivery (retail over here is €16~20).
Last edited by 1967brutus; 03-10-2023 at 06:57 AM.
#640
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Hello Frank, here is the link to where to purchase the baffles. https://ch-ignitions.com/product-cat...saito-baffles/
Roger
Roger
#642
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Hello guys.
Does anybody know the part number of a membrane kit for carburetor FG90R3?
My engine seems not to get enough fuel anymore. Does not want to go to full power.
What is the best gap for new CM6 plugs? I found a lot different opinions
Thanks
Does anybody know the part number of a membrane kit for carburetor FG90R3?
My engine seems not to get enough fuel anymore. Does not want to go to full power.
What is the best gap for new CM6 plugs? I found a lot different opinions
Thanks
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Didier (07-04-2024)
#644
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Carburetor gasket kit is K10-WYD for the FG90R3.